Information transmission method, information transmission system, imaging apparatus and information transmission method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention provides information transmission that can be used for various purposes such as product description in stores, exhibit description in museums and exhibitions, landmark display of buildings, advertisement display, congestion state display of amusement facilities such as amusement parks, and the like. The present invention relates to a method, an information transmission system, an imaging device, and an information transmission method.

【0002】

[Conventional technology]

Conventionally, the presentation of information on products and exhibits, the display of landmarks such as buildings, the display of advertisements, the display of congestion of amusement facilities such as amusement parks, etc. have been exclusively made of paper, banners, signboards, plates, etc. (hereinafter referred to as , For the sake of convenience, it was done in the form of textual information written on the "information presentation").

【0003】

However, such character-based information presentation is as follows: (1) When the number of information presentation objects is large, the number of information presentation objects such as signboards also increases, the important objects become inconspicuous, and the information presentation objects and information presentation objects It is difficult to grasp the correspondence with the information, and it may be misunderstood that the information of the product A is misunderstood as the information of the product B, for example. (2) In addition, since the textual information written on the information presentation can be read by anyone with normal eyesight, limited information intended only for a specific person (for example, a product). When presenting the purchase price, maximum discount rate, etc.), take conservation measures such as writing in a code, but if the code is too complicated, it is not easy to use, so it has to be simple and information. There is a risk that the maintenance effect of the product will be reduced and it will be easily read.

【0004】

Therefore, the inventors of the present invention can clarify the correspondence between the information presentation target product and the presentation information and eliminate the misunderstanding of information grasp by first using the information transmission by the optical space transmission. (Japanese Patent Application No. 2000-056260).

【0005】

In this proposal, the imaging means, the storage means for storing the images captured by the imaging means in time series, the cutting means for cutting out a specific image area from the image stored in the storage means, and the cutting means. It is characterized by including an extraction means for extracting information from a time-series brightness change of a cut-out image region and a display means for superimposing and displaying the information extracted by the extraction means on the captured image. Since it is possible to visually confirm the correspondence between information presentations (products, etc.) such as paper, banners, signs or plates, and the information on the information presentation device, incorrect information understanding, for example, information on product A can be obtained on product B. It is not misunderstood as the information of.

【0006】

[Problems to be Solved by the Invention]

By the way, in the above proposal, the captured image is stored in time series, a specific image area is cut out from the stored image, information is extracted from the time-series brightness change of the cut out image area, and the information is extracted. The extracted information is superimposed and displayed on the captured image, but there is a problem that the information is not extracted correctly when, for example, ambient light having a similar brightness change pattern is nearby. There was room for improvement in this regard.

【0007】

Therefore, the problem to be solved by the present invention is to provide an information transmission method, an information transmission system, an imaging device, and an information transmission method capable of avoiding adverse effects due to ambient light and always correctly extracting information. It is in.

【0008】

[Means for solving problems]

In order to solve the above problems, the present invention is in an information transmission method in which information to be transmitted is converted into an optical signal by a light emitting unit and output, and the optical signal is received by a light receiving unit to reproduce the information. , The light emitting unit logically determines a bit string constituting information to be transmitted, and selectively selects a bit pattern sequence from two bit pattern sequences having a low degree of correlation with each other prepared in advance according to the determination result. , The light receiving unit outputs the optical signal with the intensity modulated according to the selection result, the received optical signal is binarized according to the intensity, and the bit pattern sequence included in the binarized result is the said. When corresponding to any one of two bit pattern sequences having low correlation with each other prepared in advance, the corresponding logic signal is generated to reproduce the information. In the present invention, light modulated by two bit pattern sequences is emitted from the light emitting unit, and the information contained in the light is decoded by the light receiving unit.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the optical communication method and the optical communication device in the present embodiment have a basic configuration of a combination of a light emitting unit and a light receiving unit. The light emitting unit is attached to information presentation objects such as landmarks such as products, exhibits, and buildings, advertising signs, and amusement facility mixture, and the light receiving unit is a person who visually observes the information presentation objects (hereinafter referred to as). Carried by "user"). The number of light emitting units corresponds to the number of information presentation objects, and the number of light receiving units corresponds to the number of users.

【0010】

(Conceptual explanation) FIG. 1 is a conceptual configuration diagram of the light emitting unit 1. The light emitting unit 1 is an electronic circuit unit 6 including a logic determination unit 2, a first pattern series generator 3, a second pattern series generator 4, and a drive unit 5, and a battery that supplies a DC power supply EV to the electronic circuit unit 6. It consists of 7 and a light emitting unit 8.

【0011】

The logic determination unit 2 takes in any digitized and binarized transmission information TX consisting of the logic signal 0 and the logic signal 1 bit by bit, determines the bits, and if it is the logic signal 1, the first The pattern generation command C1 is output to the pattern series generation unit 3, and if the logic signal is 0, the pattern generation command C0 is output to the second pattern series generation unit 4.

【0012】

The first pattern sequence generator 3 and the second pattern sequence generator 4 each have a specific bit pattern sequence (first pattern sequence) having a low correlation with each other when the pattern generation command C0 / C1 is output from the logic determination unit 2. Pattern sequence SA, second pattern sequence SB) is generated.

【0013】

The drive unit 5 modulates the DC voltage EV using the first and second pattern sequence (SA / SB) generated by the first pattern sequence generator 3 and the second pattern sequence generator 4, and the modulated voltage thereof. The light emitting unit 8 is driven by mEV. The light emitting unit 8 emits light P having a time-series brightness change pattern of emitting light at a modulation voltage of mEV (ON section) and turning off at 0V (OFF section).

【0014】

FIG. 2A is a diagram showing an example of the first and second pattern series (SA / SB). In this figure, for example, when an arbitrary transmission information TX is a bit string of "01011000 ...", the TX i bit = 0 i + 1 bit = 1 i + 2 bits = 0 i + 3 bits = 1 i + 4 bits = 1 i + 5 bits = 0 i + 6 bits = 0 i + 7 bits = 0 Therefore, the logic judgment unit 2 i bit = C0 i + 1 bit = C1 i + 2 bits = C0 i + 3 bits = C1 i + 4 bits = C1 i + 5 bits = C0 i + 6 bits = C0 i + 7 bits = C0 C0 and C1 are output in sequence.

【0015】

Therefore, the first pattern sequence generator 3 and the second pattern sequence generator 4 to which these C1 and C0 are input generate and output the corresponding first pattern sequence SA and second pattern sequence. Then, the drive unit 5 outputs the mEV corresponding to the sequentially input SA and SB, and as a result, the transmission information TX is SB, SA, SB, SA, SA, SB, SB, SB ... It will be output from the light emitting unit 8 as light P having the time-series brightness change pattern of.

【0016】

In the present embodiment, the first pattern series SA and the second pattern series SB are different from the luminance change pattern of the ambient light that causes noise on the light receiving unit 20 (see FIG. 3) side, which will be described later. Must be set. Moreover, it is important that there is no big difference in the number of "1" (lights) and "0" (lights) in these pattern series, and that there is no regularity like an asynchronous pseudo-random number pattern. ..

【0017】

Further, in the present embodiment, the number of bits of the first pattern series SA and the second pattern series SB is set to "5", but the number of bits is not limited to this. For example, if the number of bits is increased, it becomes easier to distinguish the change in the brightness of the ambient light, but on the other hand, the transmission efficiency is impaired. Therefore, the number of bits may be flexibly set depending on whether the elimination of ambient light is emphasized or the transmission efficiency of the transmission information TX is emphasized.

【0018】

Further, in the present embodiment, in the first pattern sequence SA and the second pattern sequence, it may be possible to generate the other pattern sequence from one pattern sequence. In this case, for example, as shown in FIG. 2B, the first pattern sequence SA and the second pattern sequence are generated by passing the second pattern sequence SB through the non-inverting buffer 9 and the inverting buffer 10. Can be done. That is, in FIG. 1, the first pattern series generation unit 3 and the second pattern series generation unit 4 can be configured as one.

【0019】

FIG. 3 is a conceptual configuration diagram of the light receiving unit 20. The light receiving unit 20 includes a light receiving unit 21, a pattern sequence determination unit 22, a logic signal 1 generating unit 23, and a logic signal 0 generating unit 24. The light receiving unit 21 converts external light into an electric signal. In particular, the light receiving unit 21 receives the light P output from the light emitting unit 1 (see FIG. 1), and the ON (lighting) section and OFF (off) of the light P are received. A logical judgment is made by discriminating from the section, and a digital signal PD based on this is generated.

【0020】

The pattern sequence determination unit 22 stores two reference pattern sequences (SAr / SBr), and stores the two pattern sequences (SA / SB) and the reference pattern sequence (SAr / SBr) included in the bit array of the digital signal PD. In comparison, if the bit array of the digital signal PD contains the SAr pattern, the first pattern sequence determination signal Ca is output during that section, while the SBr pattern is included in the bit array of the digital signal PD. If so, the second pattern sequence determination signal Cb is output during that section.

【0021】

The logic signal 1 generation unit 23 and the logic signal 0 generation unit 24 generate the logic signal 1 while the first pattern sequence determination signal Ca is output from the pattern sequence determination unit 22, and the pattern sequence determination unit 22 generates the logic signal 1. While the second pattern sequence determination signal Cb is being output, logic signal 0 is generated and those logic signals are output in chronological order to obtain the received information RX based on the light P received in chronological order. Reproduce.

【0022】

That is, according to such a configuration, when the transmission information TX having the bit string of "01011000" is given to the light emitting unit 1, the logic determination unit 2 reads each bit of the transmission information TX one by one and reads the logic. Judgment is made, and if the logic signal is 1, the pattern generation command C1 is output to the first pattern sequence generator 3, while if the logic signal is 0, the pattern generation command C0 is issued to the second pattern sequence generator 4. Output.

【0023】

Next, the first pattern series generation unit 3 and the second pattern series generation unit 4 correspond to the pattern generation command C1 / C0 when the logic determination unit 2 issues the pattern generation command C1 / C0, respectively. Series SB is sequentially generated and output.

【0024】

Then, according to the first pattern series SA and the second pattern series SB output in this way, the drive unit 5 outputs a drive signal mEV, and the light emitting unit 8 emits light P having a time-series brightness change. It is output.

【0025】

On the other hand, when the light receiving unit 21 of the light receiving unit 20 receives the light P from the light emitting unit 1 in time series, the light receiving unit 21 outputs a digital signal PD based on the above-mentioned time series brightness change, and the pattern The sequence determination unit 22 sequentially compares this PD with the reference pattern sequence (SAr / SBr).

【0026】

Then, the pattern sequence determination unit 22 compares and determines the match / mismatch of SAr and SBr, and outputs the first pattern sequence determination signal Ca and the second pattern sequence determination signal Cb for each determination result.

【0027】

The logic signal 1 generation unit 23 and the logic signal 2 generation unit 24 generate the logic signal 1 and the logic signal 0 based on the determination result by the pattern sequence determination unit 22, and finally the same as the transmission information TX. Reproduce the received information RX having a bit string (01011000).

【0028】

(First Embodiment) Next, the first embodiment to which the present invention is applied will be specifically described. 4A and 4B are views showing a light emitting unit and a light receiving unit according to the first embodiment. FIG. 4A is a front perspective view of the light emitting unit 30, FIG. 4B is a front perspective view of the light receiving unit 40, and FIG. 4C is a light receiving unit. It is a rear perspective view of the unit 40. The light emitting unit 30 is configured by attaching a light emitting window 32 to an outer box (preferably an outer box having a drip-proof structure suitable for outdoor installation) 31 having an appropriate shape. The light receiving unit 40 is an imaging device such as a digital camera, which is configured by attaching an optical lens unit 42, a shutter key 43, a liquid crystal display 44, and the like to a body 41 having a shape suitable for handheld use.

【0029】

FIG. 5 is an electrical internal configuration diagram of the light emitting unit 30 and the light receiving unit 40. In this figure, the light emitting unit 30 includes a transmission data memory 33, a pattern data memory 34, a timing generator 35, a CPU 36, a light emitting unit 37, and a light emitting window 32. The light receiving unit 40 includes an optical lens unit 42, a shutter key 43, an imaging unit 45, a captured image buffer 46, a display buffer 47, a liquid crystal display 44, a timing generator 48, a CPU 49, a pattern data memory 50, a reference image buffer 51, and a frame. It includes a series buffer 52, a correlation evaluation image buffer 53, a buffer for work such as binarization 54, and a data list memory 55. The power supply units (batteries, etc.) of the light emitting unit 30 and the light receiving unit 40 are not shown.

【0030】

Explaining the functions of each part, first, the timing generator 35 of the light emitting unit 30 generates a stable clock signal CK having a predetermined cycle synchronized with the image capture clock signal PCK of the timing generator in the light receiving unit 40 described later.

【0031】

The CPU 36 of the light emitting unit 30 synchronizes with the clock signal CK from the timing generator 35, first extracts the i-th bit of the transmission information TX stored in the transmission data memory 33, determines the bit value, and determines the logic signal. If it is 1, the first pattern series SA is taken out from the pattern data memory 34, if the logic signal is 0, the second pattern series SB is taken out from the pattern data memory 34, and the first pattern series SA and the second pattern series SB are emitted from the light emitting unit. Output to 37. The light emitting unit 37 emits light in the section of the logic signal 1 and turns off in the section of the logic signal 0, and outputs light P having a time-series luminance change pattern through the light emitting window 32.

【0032】

On the other hand, the image pickup unit 45 of the light receiving unit 40 is composed of an image sensor such as a CCD (Charge-Coupled Devices) or a CMOS (Complementary Metal-Oxide Semiconductor), and the subject captured via the optical lens unit 42. The image is converted into an electrical frame image signal and output to the captured image buffer 46 at a cycle synchronized with the captured image clock signal CCD. The CPU 49 of the light receiving unit 40 controls the overall operation of the light receiving unit 40, and sends the frame image captured in the captured image buffer 46 to the display buffer 47 as it is and displays it on the liquid crystal display 44, and the shutter key 43. At the time of the operation of, the image captured in the display buffer 47 is captured in an image memory (not shown), and the light receiving unit 40 (shown) is particularly characterized in that the following processing is performed.

【0033】

That is, the CPU 49 of the light receiving unit 40 sequentially stores the frame images captured in the capture image buffer 46 in synchronization with the capture clock signal PCK in each plane of the frame time series buffer 52 for each frame image. Here, the frame time series buffer 52 includes first plane to nth plane having a storage capacity corresponding to the size of one frame image, and the number of planes n is at least the pattern series in the light emitting unit 30. Corresponds to the number of bits N of (SA / SB). For example, in the example of the above embodiment, since the number of bits of SA and SB is 5 bits (N = 5), the number of planes n of the frame time series buffer 52 is at least 5 planes from the 1st plane to the 5th plane. Become. Hereinafter, for convenience of explanation, the number of bits N of the pattern series (SA / SB) is set to 5 bits, and the number of planes n is also set to 5.

【0034】

The writing order of the frame images from the first plane to the fifth plane is as follows. 1st frame image = 1st plane 2nd frame image = 2nd plane 3rd frame image = 3rd plane 4th frame image = 4th plane 5th frame image = 5th plane 6th frame image = 1st plane 7th frame image = 2nd plane 8th frame image = 3rd plane 9th frame image = 4th plane 10th frame image = 5th plane In this way, the writing operations from the first plane to the fifth plane are sequentially performed cyclically.

【0035】

The CPU 49 of the light receiving unit 40 controls the writing order to each plane (actually, controls the value of the buffer pointer n), and in parallel, a time-series brightness change pattern from the frame images written to each plane. The process of extracting the pixel area with and binarizing the brightness change pattern with the work buffer 54 such as binarization, the binarized data (corresponding to the above digital signal PD), and the pattern data memory. Compared with the reference pattern sequence (SAr / SBr) held at 50, if it matches SAr, logic signal 1 is generated, while if it matches SBr, logic signal 0 is generated. The process of storing those logical signals in the data list memory 55 is executed. Further, the liquid crystal display 44 of the light receiving unit 40 displays a subject image including the light emitting area by the light emitting unit 30, and further, information on the light emitting area is blown out to a specific part (for example, the center part of the screen) of the display area. It imitates the figure of and displays it in an overlapping manner. The reference image buffer 51 is for image stabilization, and how to use it will be described later.

【0036】

FIG. 6 is a diagram showing a specific usage pattern of the light emitting unit 30 and the light receiving unit 40. In the figure, the light receiving unit 40 is directed to the landscape of the city center at an angle of view α. Buildings 59, 60, 61, TV tower 62, automobiles 63, 64, etc. are included in the angle of view α, and the light emitting unit 30 is attached to buildings 59, 61, TV tower 62 (bright spots 65 to 67). position). Although the light emitting unit 30 itself cannot be visually recognized by the user of the light receiving unit, each light emitting unit 30 emits light P having a time-series brightness change pattern, and the bright spots 65 to 67 are , Corresponds to that light P. In addition to the bright spots 65 to 67 due to the light P, the headlight light 68 of the automobile 63 exists in each α as ambient light.

【0037】

By the way, on the liquid crystal display 44 of the light receiving unit 40, images of buildings 59, 60, 61, TV tower 62 and automobiles 63, 64 existing in the angle of view α (building image 59A, 60A, 61A, TV tower image 62A, automobile image) 63A, 64A), each bright spot image 65A to 67A, and headlight light 68 are projected.

【0038】

The light receiving unit 40 extracts each bright spot image 65A to 67A, compares the luminance change pattern with the reference pattern (SAr / SBr), and generates a logic signal 1 if it matches the SAr, and also in SBr. If they match, the logic signal 0 is generated. Then, the bit string composed of the logic signal 1 and the logic signal 0 is converted into a character string, and the conversion result is displayed on the liquid crystal display 44, for example, by overlapping the figure 69 such as a balloon.

【0039】

According to an information transmission system having such an effect, a light emitting unit 30 attached to various landmarks in an urban area allows a user of the light receiving unit 40 to obtain information such as a building name and a tenant from a remote location. be able to. In addition, even if it is not a large-scale object such as a building, if the light emitting unit 30 is attached to the product displayed in the store or the object displayed in the museum or exhibition, the product name and the explanation of the exhibit will be explained. Information can be obtained from remote locations. In the present embodiment, the headlight light 68 is illustrated as the ambient light, but the present invention is not limited to this, and it is possible to distinguish each bright spot even if it is a fluorescent lamp. .. This is because in the case of flashing light with periodicity such as a fluorescent lamp, the flashing cycle is only synchronized with the frequency of the power supply, which is clearly different from the brightness change pattern of the light P at each bright spot. Is.

【0040】

FIG. 7 is a flowchart of a light emitting processing program executed by the CPU 36 of the light emitting unit 30. In this flowchart, the CPU 36 first extracts 1 byte (8 bits) of information from the transmission information TX stored in the transmission data memory 33 (step S10). Next, the first bit of the information is taken out (step S11), a determination is made (step S12), and if the logic signal is 1, the light emitting unit 37 is blinked in the first pattern sequence (SA) (step S13), and the logic is set. If the signal is 0, the light emitting unit 37 is blinked in the second pattern series (SB). Then, after repeating the above process for one byte (step S15), the process returns to step S10 and is executed, and the process ends when the end of the information is reached.

【0041】

FIG. 8 is a timing chart of the light emitting operation of the light emitting unit 30. In this example, the transmission information TX is assumed to be a character string "X", "T", "o", "w", "e" ..., And the bit string corresponding to that character string ("X" in the figure). An example of converting each bit of " 01011000) into the first pattern sequence (SA: 11010) or the second pattern sequence (SB: 00101) is shown. The light emitting unit 37 of the light emitting unit 30 blinks in the first pattern series (SA: 11010) or the second pattern series (SB: 00101), and outputs the above transmission information TX according to the blinking pattern.

【0042】

FIG. 9 is a timing chart of the light emitting side (light emitting unit 30 side) and the light receiving side (light receiving unit 40 side). On the light emitting side, the pattern switching clock CP is generated once every five times in the clock signal. The bit output clock CB is created by the timing generator 35 shown in Fig. 5 (a).

【0043】

On the other hand, on the light receiving side, the pattern switching clock CP resets the write plane designation pointer of the frame time series buffer 52 in FIG. 5 (b). The byte data extraction (step S16) in FIG. 7 is performed in synchronization with this CP. Further, 1-bit extraction (step S11), determination (step S12), and pattern sequence selection (steps S13, S14) are performed in synchronization with the clock signal CK output from the timing generator 35.

【0044】

One blinking cycle (tSlot) of the light P on the light emitting side is set in consideration of the imaging shutter time (ts) on the light receiving side. In addition, the light receiving side is out of phase with the transmitting side so that imaging (switching detection of light P ON (lighting) / OFF (lighting off)) can be performed in a timely manner with one blinking cycle (tSlot) set on the transmitting side. Set td) so that it falls within the following range.

【0045】

That is, when the phase on the light receiving side is slightly delayed, on the transmitting side, one blinking cycle (tSlot) is set to a time longer than the sum of the imaging shutter time (ts) and the phase shift (td), and conversely, If the phase on the light receiving side advances slightly, set one blinking cycle (tSlot) so that the degree of advance is negligibly small with respect to the imaging shutter time (ts).

【0046】

FIG. 10 is a flowchart of a light receiving processing program executed by CPU 49 of the light receiving unit 40. When this flowchart is started, first, the timing generator 48 is initialized (step S20), and then the following processes are repeatedly executed.

【0047】

<Frame buffer registration process>: Step S21 FIG. 11 is a flowchart of the frame buffer registration processing subroutine program. In this flowchart, first, the frame image from the imaging unit 45 is taken into the captured image frame buffer 46 (step S21a), and then the frame image is subjected to filtering processing such as smoothing (step S21b). Next, frame correlation processing is performed between the frame image subjected to this filtering process and the reference frame image in the reference image buffer 51, and as a result, a motion vector is detected (step S21c), and the motion amount of this motion vector is corrected. Determine if it is within the threshold (step S21d).

【0048】

If the amount of motion of the motion vector is not within the correction threshold, it is determined that the frame image has no motion or the amount of motion is small, and the frame image is set to the plane specified by the buffer pointer n of the frame time series buffer 52. Store (step S21e) and replace the reference frame image in the reference image buffer 51 with this frame image (step S21f). On the other hand, when the motion amount of the motion vector is within the correction threshold value, it is determined that this frame image has a large motion amount, motion correction is performed on this frame image, and the corrected frame image is displayed. Store in the plane specified by the buffer pointer n of the frame time series buffer 52 (step S21g).

【0049】

Next, the buffer pointer n is updated, the captured image is stored in the display buffer 47, and then the process returns to FIG. When the buffer pointer n = the maximum value N, the process proceeds to the signal detection & bit extraction process in step S23.

【0050】

<Signal detection & bit retrieval processing>: Step S23 FIG. 12 is a flowchart of the signal detection & bit extraction processing subroutine program. In this flowchart, first, the update request list 551 in the data list memory 55 is initialized (step S23a). Next, the frame image group corresponding to the ON (lighting) timing of the optical P in the frame time series buffer 52 is read, the average image obtained by averaging each dot value is obtained (step S23b), and then the optical P is turned off (turned off). ) Read the frame image group corresponding to the timing, and similarly obtain the average image obtained by averaging the values of each dot (step S23c). Then, a fluctuation width image consisting of the maximum value of the brightness at each dot position of the entire frame image group is obtained (step S23d). Next, an absolute correlation evaluation image represented by an absolute value obtained by subtracting the average value image obtained in the above step S23c from the average value image obtained in the above step S23b is obtained (step S23e). Next, the (normalized) correlation degree evaluation image defined by this absolute correlation degree evaluation image / fluctuation width image × 255 is obtained (step S23f).

【0051】

That is, by referring to the correlation degree evaluation image obtained in this way, the image region fluctuating as the first pattern series has a high correlation value in the positive direction, and the image region fluctuating as the second pattern series has a negative direction. It can be seen that a high correlation value is obtained with.

【0052】

Next, a binarized image is generated from the correlation evaluation image obtained in step S23f (step S23g), and each region in this binarized image is labeled for the same continuous region, and each region is labeled. The center coordinates of the region are additionally set in the update request list 551 as the first pattern series (step S23h). Next, the threshold value of the correlation degree evaluation image is sign-inverted to generate a binarized image (step S23i), and similarly, each region is additionally set in the update request list 551 as a second pattern series (step S23i). Step S23j). After that, it is determined whether or not the update request list 551 is empty, and if it is not empty, the process proceeds to the list update process in step S25.

【0053】

FIG. 13 is a flowchart of the list update processing subroutine program. First, one pattern (hereinafter referred to as "request pattern") is extracted from the update request list 551 set in step S23 above (step S25a), and a pattern that matches the coordinates registered in advance exists in this request pattern. It is determined whether or not to do so (step S25b). Then, if there is a match, it is determined whether this request pattern is the first pattern sequence or the second pattern sequence (step S25d). If the request pattern does not match both the first pattern sequence and the second pattern sequence, create a new list entry 552, perform coordinate registration processing, and initialize the bit buffer 553 (step S25c). ), Determine the request pattern (step S25d).

【0054】

Then, if the request pattern is the first pattern series, "1" is added to the corresponding entry of the bit buffer 553 (step S25e), and if it is the second pattern, "0" is added to the corresponding entry of the bit buffer 553. Is added (step S25f), and in each case, the above processing is repeatedly executed until it is completed (step S25g), and the process proceeds to the processing of step S24 in FIG.

【0055】

<Display processing>: Step S24 FIG. 14 is a flowchart of the display processing subroutine program in step S24. In this flowchart, first, it is determined whether or not there is any bit data that has not been updated in this update process (step S24a). Then, if the bit data is not updated, it is deleted from the data list memory 55 (step S24b), and if there is an update, whether or not one byte of bit data is buffered in the bit buffer 553 is checked. Determine (step S24c).

【0056】

If the bit buffer 553 is not buffered by 1 byte (8 bits), the image of the display buffer 47 is sent to the liquid crystal display 44 for display (step S24e), and the bit buffer is buffered by 1 byte (8 bits). In this case, it is added to the byte data FIFO (not shown) of the data list memory 55, the bit buffer 553 is cleared (step S24d), and then the image of the display buffer 47 is transferred to the liquid crystal display 44 for display (step S24e). .. Next, the bright spot corresponding to the light P in the center is selected, and the information character string transmitted by the arrow and the light P is displayed so as to overlap the display image (step S24f). On the other hand, for the other bright spots, only the arrows are overlapped (step S24g), and the loop returns to the loop shown in FIG.

【0057】

In the frame buffer registration process of FIG. 11, the correction by the user's camera shake shooting was not considered, but in such a case, when the signal detection & bit extraction process is executed, the correlation degree calculation (step S23e, There is a problem that it causes a problem in S23f). FIG. 15 illustrates each frame image when camera shake shooting by the user occurs in consideration of the above problems. In the figure, the five images 70 to 74 are the frame images stored in each plane of the frame time series buffer 52, the value of n is the pointer in the frame time series buffer 52, and each frame image 70 to 74 is the user. (The hatched areas 70a to 74a in each of the frame images 70 to 74 shown in the figure represent the missing pixel area due to the motion correction). In this state, the amount of movement between each frame image and the reference frame image stored in the reference image buffer 51 is detected, and each frame image 70 to 74 is horizontally moved in the direction of eliminating the amount of movement. We are trying to solve the problems that occur when calculating the degree of correlation.

【0058】

FIG. 16 is a conceptual diagram of the correlation degree calculation (steps S23e and S23f) in the signal detection & bit extraction processing program of FIG. 12, and the two correlation degree evaluation target images 75 and 76 have bright spots 75a, 75b and 76a, respectively. Is included. Here, one image 75 is an image binarized after the correlation degree evaluation for the first pattern series SA, and the other image 76 is an image binarized after the correlation degree evaluation for the second pattern series SB. .. Assuming that the coordinate positions in the image of the bright spots 75a, 75b, and 76a are (300,98), (159,121), and (20,24) for convenience, the update request list 551 shows the coordinates as the information of the bright spot 75b. (300,98) and the pattern series "SA (first pattern series)" are the coordinates (159,121) and the pattern series "SA (first pattern series)" as the information of the bright spot 75a, and the information of the bright spot 76a. The coordinates (20,24) and the pattern series "SB (second pattern series)" are stored as.

【0059】

FIG. 17 is an example of the storage state of the data list memory 55 after executing the list update processing program of FIG.

【0060】

After executing the list update processing program, the logic signal 0 and the logic signal 1 are accumulated in the bit buffer 553, and are cleared when 8 bits are accumulated. For example, (a) (b) illustrates until the entry of the coordinates (20,24) corresponding to the bright spot 76a in FIG. 16 is completed. That is, in FIG. 17 (b), the bit buffer on the right is buffered as 01000001 = 41H = information character string'A', and then the entry of the coordinates (300,98) corresponding to the bright spot 75b starts.

【0061】

As described above, according to the first embodiment, the light receiving unit 40 receives and detects the bright spot due to the light P of the light emitting unit 30 existing in the angle of view by taking a picture, and the bright spot The pattern based on the emission intensity is binarized, and it is determined whether or not the binarized pattern matches any of the prepared pattern series that do not correlate with each other. Then, based on the determination result, it is converted into a logic signal 1 or 0 and the transmission information TX is reproduced. Therefore, the influence of ambient light that does not include such a pattern sequence can be reliably eliminated. Further, according to FIG. 15, since the motion of the captured image can be corrected due to the user's camera shake, the transmission information TX can be reliably reproduced even when the user holds the light receiving unit 40 in his / her hand for shooting. It is possible to improve usability.

【0062】

In the above description, the light receiving unit 40 is provided with a liquid crystal finder (liquid crystal display 44) such as an electronic still camera, but the present invention is not limited to this, and is not limited to this, for example, as shown in FIG. 18 (a). The body 53 may be a light receiving unit provided with an optical lens 50 and an operation button 51, a display unit 54 for displaying character information, and a direct-view finder 55 for adjusting the shooting direction.

【0063】

According to this, as shown in FIG. 6B, by looking into the direct-view finder 55, pointing the shooting direction at the target object, and pressing the operation button 51, information from the target object is received and displayed on the display unit 54. It can be displayed. In this way, it is not necessary to use a relatively expensive liquid crystal finder (liquid crystal display 44 in FIG. 5), and the cost of the light receiving unit 50 can be reduced. Since the user cannot confirm the display of the display unit 54 while looking into the direct-view finder 55, the user may issue an alarm or a synthetic voice for notifying the acquisition of information from the target object. (Second Embodiment) In the first embodiment described above, at least 40 frames (8 × 5 = 40 frames) are required to transfer one character (uncompressed 8-bit code text data). I need an image. Therefore, it takes 1.33 [seconds] to transfer one character, and if the number of characters in the transmitted information increases, it takes a corresponding amount of time, which is a disadvantage.

【0064】

To avoid this inconvenience, it is most desirable to simply increase the frame rate, but if the frame rate is set to 30 fps (frame / second) and the transfer speed is increased 10 times, 30 x 10 = 300 fps. It requires a frame rate.

【0065】

In addition, in order to reduce the amount of data processing while increasing the frame rate, it is conceivable to reduce the number of dots in the frame image (for example, if the amount of data is 1/10 in the above 300 fps state, it will be detected. The area may be reduced to less than the number of pixels of the original image (for example, 640 × 480 dots), for example, about 228 × 152 dots). However, in this case, the area of the 1-dot pixel in the image angle is also reduced to 1/10, so even in the case of information transmission by the 1-dot bright spot in 640 x 480, the detection area is 10 times larger. The change in the brightness of a part of the area is reduced to 1/10, and the change width of the change in the brightness of the pixel is reduced to 1/10. This causes the inconvenience that the area in charge of one dot of the light source is further expanded.

【0066】

For example, instead of a light source that is as inconspicuous as a miniature bulb, a light source with 10 times the area (for example, a globe-shaped light source) must be used, or the area becomes smaller in one dot. In order to increase the amplitude of the brightness change by a minute, it is necessary to set the brightness at the time of lighting several times.

【0067】

That is, in the first embodiment described above, it is possible to simultaneously satisfy the requirement of increasing the amount of data transfer and reducing the amount of data to be handled while capturing the change in brightness of a small area (decreasing the number of pixels). There was a drawback that it could not be done.

【0068】

Therefore, in the second embodiment, in order to improve the above-mentioned drawbacks, (1) By performing "partial readout" from the detection area of the imaging means and shifting the readout area every cycle, the target modulation signal is detected in high definition from the angle of view and decoded. .. (2) Utilize the sub-sampling (skipping) function of the imaging means to detect signals at all angles of view in images with a high frame rate. (3) Also, combine the above two (1) and (2). That is the point.

【0069】

Hereinafter, the second embodiment will be described in detail. For the components common to the first embodiment described above, the first embodiment and the corresponding drawings shall be referred to, and only different components (or newly added components) shall be referred to. It will be shown in the figure.

【0070】

FIG. 19 is an electrical internal configuration diagram of the light receiving unit 40 according to the second embodiment, and is a drawing corresponding to FIG. 5 (b) of the first embodiment. The differences from Fig. 5 (b) are as follows.

【0071】

The image pickup unit 45 is an imaging device (CMOS sensor, etc.) capable of partial readout by setting a high frame rate, and has a definition of the entire angle of view of 1280 x 960 dots and a partial readout area of 320 x 240 dots. And. In addition, the imaging unit 45 can capture an image of full dots 1280 x 960 dots at a frame rate of 15 fps, and the partial readout of 320 x 240 dots is 1/16 of the area of the above full dots. .. Therefore, when partial reading of 320 × 240 dots is performed, it is possible to capture a frame rate (about 240 fps) about 16 times.

【0072】

The captured image buffer 46 has a capacity of 320 × 240 dots for storing partial read data. The display buffer 47 has a capacity of 1280 x 960 dots for displaying the entire angle of view of the imaging unit 45 on a monitor. Further, since the frame time series buffer 52 stores partial read data in time series, each has a capacity of 320 × 240 dots. The reference image buffer 51, the correlation evaluation image buffer 53, and the work buffer 54 for binarization and the like have a capacity of 320 × 240 dots corresponding to the partial read data.

【0073】

The read position control memory 100 holds information on a partial read area of 320 × 240 dots (hereinafter referred to as read area range) in an image of full dots 1280 × 960 dots.

【0074】

FIG. 20 is a conceptual diagram of the read area range. In this figure, X₁~ X₅Is the horizontal size of the read area range (320 dots), Y₁~ Y₅Is the vertical size of the read area range (240 dots). The numbers in parentheses from (1) to (25) are the numbers in the read area range, and the search is performed in the order of the thick arrows. That is, the search is performed in the order of (1) (2) (3) (4) (5) (6) ... (25), and the final read area range (25) is reached. Then, it returns to (1) again and repeats the search. The right-pointing arrow line and the wavy arrow line indicate the search direction.

【0075】

In the illustrated example, each read area overlaps with the adjacent read area. That is, when a full-dot (1280 x 960) image is divided vertically and horizontally (for example, divided into 5 equal parts as shown in the figure), the size of each read area range is 256 × 192 dots of the area range A. The read area range (1) is 320 × 240 dots. That is, by providing an overlap (overlapping region) of 64 × 48 dots, even if a bright spot exists on the boundary line of the region range, the brightness change of the bright spot can be detected correctly.

【0076】

Next, the operation in the second embodiment will be described. FIG. 21 is a diagram showing an overall operation flowchart of the light receiving unit according to the second embodiment. In this flowchart, the total angle of view of the image sensor, 1280 × 960 dots, is divided into several read area ranges, and the process of FIG. 10 according to the first embodiment described above (steps S20 to step) for each read area. Repeat S24). That is, the read area range is initialized (step S30), and the first read area range (read area range (1) in FIG. 20) is first processed in FIG. 10 in the first embodiment (step S20). ~ Perform step S24).

【0077】

If signal detection is not performed in step S23, the determination result in step S31 becomes "NO", the process is switched to the next read area range processing (step S32), and the processing after step S20 is repeated for the read area range. .. On the other hand, when signal detection such as 5-bit code detection is performed in step S23, partial read processing is performed five times for the read area range.

【0078】

FIG. 22 is a conceptual diagram showing the correspondence between the full-dot image (1280 × 960 dots) and the read area range (320 × 240 dots). In this figure, 101 is the region obtained by the image sensor of 1280 × 960 dots, and 102 is the first readout region range. In this figure, for example, when a 5-bit code is detected, partial reading is performed 5 times per area, so that the reading area range 102 is the time t.₀~ t₄It is read a total of 5 times. The code 103 is the time t₁Read area range in, code 104 is time t₂Read area range in, reference numeral 105 is time t₃Read area range in, reference numeral 106 is time t₄Indicates the read area range in.

【0079】

As described above, in the second embodiment, the image obtained at 1280 × 960 dots is divided into a read area range of 320 × 240 dots, and each area is scanned while the first embodiment is performed. When the process of FIG. 10 (steps S20 to S24) is repeatedly executed and a bright spot with a change in brightness, that is, an n-bit code is detected in the divided area, n times for the read area range. Since partial reading is performed, it is possible to reliably capture a change in brightness in a small area, and it is possible to increase the amount of data transfer of character information. Moreover, the demand for reducing the amount of data processed can be satisfied at the same time.

【0080】

In the second embodiment, the read area range is 320 × 240 dots, but the present invention is not limited to this. In other words, if the area is divided more finely, even a higher frame rate of several thousand fps can be realized. It is also possible to make the size of the read area range variable so that one device can handle a wide range of code modulation conditions.

【0081】

(Third Embodiment) In the third embodiment, "an image pickup device using a CMOS sensor or the like as an image pickup device has a" subsampling mode "function. ] Focusing on the point, the frame rate is increased by sampling every other dot in the vertical and horizontal directions within the same angle of view. "Subsampling (or subsampling compression method)" in the above "subsampling mode" function is a kind of lossy image compression algorithm, and the point is that it does not process all the pixels in the angle of view. It is a method of thinning out dots in a checkered pattern.

【0082】

FIG. 23 is an electrical internal configuration diagram of the light receiving unit 40 according to the third embodiment. In the third embodiment, in order to utilize the above-mentioned "sub-sampling mode" function, a sub-sampling control memory 111 that holds control information about the "sub-sampling mode" function and a read condition list memory 112 are used as new components. To be equipped. The CPU 49 controls the subsampling control memory 111 while referring to the read condition list memory 112.

【0083】

FIG. 24 is a conceptual diagram showing the stored data of the read condition list memory 112. "No." is a condition number, and for each No., the vertical (vertical) and horizontal (horizontal) pixel thinning conditions, the image size obtained by the thinning conditions, and the number of divisions (number of areas) of the original image. Is specified in advance. For example, in No. 1, "4" (vertical / horizontal: meaning every 4 dots) is specified as the vertical and horizontal pixel thinning number. For example, when condition number No. 1 is applied to the original full-dot image (1280 x 960 dots), subsampling processing is performed with the thinning number "4", and 320 x 240 dots are read out as a result of the processing. Cut out the area range in sequence. When condition number No. 2 is applied, the full-dot image is subsampled with thinning numbers of "4" (every 4 dots in the vertical direction) and "2" (every 2 dots in the horizontal direction) to achieve the total angle of view size. As 640 x 240 dots, the read area range of 320 x 240 dots is sequentially cut out with. Furthermore, when condition number No. 3 is applied, subsampling processing is performed with the thinning number 2, and the read area range of 320 × 240 dots is sequentially cut out with the total angle of view image size being 640 × 480 dots. Furthermore, when condition number No. 4 is applied, sub-sampling processing is performed with "2" (every 2 dots vertically) and "1" (every 1 dot horizontally) as the thinning number, and the total angle of view image size is 1280 x. As 480 dots, the read area range of 320x240 dots is sequentially cut out. When condition number No. 5 is applied, subsampling processing is performed with the thinning number 1, and the read area range of 320 × 240 dots is sequentially cut out with the total angle of view image size being 1280 × 960 dots.

【0084】

FIG. 25 is a diagram showing an image of the full angle of view image size corresponding to the condition numbers No. 1 to No. 5 of the read condition list memory 112, and a scanned image sequentially cut out at 320 x 240 dots in the image. (a) corresponds to the condition number No. 1, and the scan target image 201 is the original full-dot image (1280 × 960 dots) thinned out every 4 vertical dots × 4 horizontal dots. It is the coarsest image, but the amount of data processed is the lightest. Further, the number of the reading area range is one of 1 in the vertical direction and 1 in the horizontal direction, and the entire angle of view can be captured at one time. Therefore, for example, when the process of FIG. 21 of the second embodiment is performed, from step S32. In the processing loop of step S20, the same read area range is always used. (b) corresponds to the condition number No. 2, and the scan target image 202 is the original full-dot image thinned out every 4 dots in the vertical direction and every 2 dots in the horizontal direction. Under this condition, the roughness of the image in the vertical direction is the same as that in (a) above, but is finer in the horizontal direction than in (a) above. Further, since the number of the reading area ranges is three, that is, 3 in the vertical direction and 1 in the horizontal direction, for example, when the process of FIG. 21 of the second embodiment is performed, in step S32, the reading position (x, y) is horizontally formed. ) Is looped with (0,0), (320,0), (640,0). (c) corresponds to the condition number No. 3, and the scan target image 203 is the original full-dot image thinned out every 2 dots vertically × 2 dots horizontally. (d) corresponds to the condition number No. 4, and the scan target image 204 is the original full-dot image thinned out every 2 dots in the vertical direction and every 1 dot in the horizontal direction. (e) is the condition number No. Corresponding to 5, the scan target image 205 is the original full-dot image thinned out every 1 vertical dot x 1 horizontal dot. It is the most precise, but the amount of data processing is the heaviest. Further, in these (c), (d), and (e), a plurality of read area ranges are set vertically and horizontally. Therefore, when the loop is set, for example, the second read area range (x, y) is (320). , 0) (959,959) becomes 640 x 960 dots. However, since the thinning condition of the read condition list memory 112 is set according to each condition number, a read area range of 320 × 240 dots is always obtained, and as described in the second embodiment above. Process while overlapping the read areas.

【0085】

FIG. 26 is a diagram showing an overall operation flowchart of the light receiving unit 40 according to the third embodiment. In this flowchart, the scan control method of the partial area (read area range) in the full screen, which is performed in the second embodiment, is changed according to each subsampling mode. When there is signal detection (luminance fluctuation pattern detection of bright spot), the processing in step S42 is fixed and looped.

【0086】

First, the condition number No. 1 stored in the read condition list memory 112 is referred to (step S41), and a very rough search is performed on the entire screen at the same rate (step S42; same as the process in FIG. 21). In this case, under condition number No. 1, for example, in the case of a 5-bit pattern, signal detection processing is performed every time 5 images are acquired (in the case of a relatively wide range of activation fluctuations, 1 / The signal can be detected even if it is acquired with 16 accuracy.) The display process in step S42 (display process in step S24 in FIG. 21) is controlled according to the sampling mode.

【0087】

If no signal is detected in the rough search state (scanned image 201 in FIG. 25), the condition number is updated and the same process is performed (step S43). For example, when the condition number is updated from No. 1 to No. 2, it is refined in the horizontal direction, so that the scanning process for each area size of the entire image is performed in step S42. When a signal is detected at this stage, the search ends in the read area range, and the signal binarization process is started.

【0088】

In this way, the condition number is updated to gradually increase the definition, and the scan amount for the entire pixel area is increased while searching for smaller signal detection. Then, when the condition number No. 5 is reached, the condition number No. 1 is restored. That is, the setting of this read condition list is repeated until the change in brightness is detected.

【0089】

By doing so, in the image including the bright spot to be detected, the signal can be detected quickly even when the angle of view size is wide. In other words, the initial capture was performed using a coarse sample (scanned image 201 in FIG. 25) at first, and the fineness of the sample was gradually increased only when it was not captured. Can be shortened.

【0090】

(Fourth Embodiment) The fourth embodiment is extremely resistant to the influence of adjacent light rays (noise corresponding to fading such as radio waves, multipath, interference, etc.), and reduces the transmission speed. For the purpose of prevention, when detecting a signal in a captured image, a detection / capture mode that emphasizes noise resistance and environmental resistance, and a decoding that decodes after the area / target dot is determined by the detection by the mode. It is characterized by being divided into modes to enable reliable signal detection and high-speed decoding after signal detection. As a method of realizing this, the detection / capture mode is performed by low-speed frame rate processing (detection processing that makes use of the correlation of time-series patterns), and signal modulation (light emitting unit 301 side) and signal detection (light receiving unit 40 side) are performed. Do. On the other hand, the decoding mode is performed by high-speed frame rate processing, and the process of determining the threshold value for signal determination and the process of binarizing will be described in detail.

【0091】

In the fourth embodiment, the newly added components are illustrated by appropriately referring to the drawings of the first embodiment for the components common to the first embodiment. ..

【0092】

The difference between the fourth embodiment and the first embodiment is that the data (information character string) transmitted in the fourth embodiment is very high speed, and the entire screen is displayed. The point is that there is no monitor update.

【0093】

FIG. 27 is an electrical internal configuration diagram of the light emitting unit 301 of the fourth embodiment, and the description of the configuration overlapping with the first embodiment will be omitted. The newly added configuration is the part surrounded by the broken line in the figure, and corresponds to the pattern bit counter 38 and the byte counter 39. These operations will be described in detail in the flowchart of FIG. 28. The light emitting unit 301 can switch the intensity of the light P in the ON state between high brightness H (hereinafter "ON (H) state") and low brightness L (hereinafter "ON (L) state"). it can. This has a relationship of "OFF state" <"ON (L) state" <"ON (H) state" when viewed in terms of brightness.

【0094】

FIG. 28 is a diagram showing an operation flowchart of the light emitting unit 301. First, the source data consisting of the information character strings to be output is converted into bit data, the DC component is removed, and then stored in the transmission data memory 33 (step S51). Next, after initializing the pattern bit counter 38 and the byte counter 39 (step S52), one bit is taken out from the pattern data memory 34 (step S53), and one byte of bit data is taken out from the transmission data memory 33 (step S52). S54). It is determined whether or not the pattern bit is 0 (logical signal 0) (step S55).

【0095】

Then, if the logic signal is 0, the modulation condition of "" 0 = OFF state, 1 = ON (L) state is applied to the 1 byte (step S56), while the pattern bit is the logic signal 0. If not, the modulation condition of "" 0 = OFF state, 1 = ON (H) state is applied to the 1 byte (step S57).

【0096】

Next, the byte counter 39 is incremented (however, if the data ends, the byte counter returns to the first byte) (step S58), and the above steps S53 and subsequent steps are repeated until the completion of 64 bytes is determined (step S59). On the other hand, when it is determined that the completion of 64 bytes is determined, the pattern bit counter 38 is incremented (however, if it is the end of data, it returns to the first byte) (step S60), and the above steps S53 and subsequent steps are repeated. Note that steps S58 to S60 are cyclically controlled, and the output signal is 64 bits (8 bytes) of transmission data and fluctuates according to one upper pattern bit.

【0097】

FIG. 29 is an explanatory diagram of removing the DC component which is a bias of the 1 and 0 bits in the bit string of the source data composed of the output information character string. DC component removal is also called "equalization of 0/1 dispersion", and when imaging at a low frame rate with the light receiving unit 40 described later, the integration level within a predetermined time is kept as constant as possible regardless of the nature of the source data. Made to keep.

【0098】

First, if the information character string (a) to be sent is "XTower ...", the first character "X" is ASCII code "58H", so the binary string (b) "01011000" as shown in the figure. ". Next, the bit string (c) "10100111" which is the negation of the binary string (c) "01011000" is generated, and both are mixed in the order of the bit of the binary string (b) and the bit string (c). Hereinafter, other characters are processed in the same manner to generate transmission data with 0/1 dispersion equalization. In FIG. 29, the DC component is removed by mixing with a simple negative bit string, but various bit string conversions that suppress the continuity of 0 or 1 can be considered, for example, CD. Other methods, such as EFM modulation used for recording sequences called pits on (compact discs), may be used.

【0099】

FIG. 30 is a diagram showing a luminance fluctuation pattern in the light emitting unit 301. In this figure, the diffusion code pattern is "00101", and each bit of the diffusion code pattern is a pattern bit.

【0100】

In the figure, (A) shows the luminance fluctuation pattern when viewed in a long cycle, and as a whole (as the envelope of the luminance fluctuation signal), the luminance changes according to the diffusion code pattern, and the time is very short. It fluctuates ON (H) and ON (L). The middle row (B) shows one pattern bit period when the transmission data bit is 64 bits, and the lower row (C) shows the luminance fluctuation pattern when viewed in a short cycle. According to this figure, when (A) is observed with a long imaging period and shutter time on the light receiving unit 40 side, it is possible to capture the luminance fluctuation due to the diffusion code pattern that becomes the envelope of (A) with the low-pass filter applied. (Hereinafter, such a signal detection method is referred to as "detection / capture mode"). On the contrary, when (A) is observed on the light receiving unit 40 side with a short imaging cycle and shutter time, it is possible to capture the brightness fluctuation of the original signal level as represented by (C). (Hereinafter, such a signal detection method is referred to as "decoding mode"). [0101]

FIG. 31 is a diagram showing an operation flowchart of the light receiving unit 40 according to the fourth embodiment. This flowchart is divided into a "detection / capture mode" (step S72 to step S78) and a "decoding mode" (step S79 to step S84).

【0102】

The "detection / capture mode" performs robust signal detection that is not affected by various ambient lights even if the brightness fluctuates even slightly, and if a signal is detected, baseband decoding processing for the specified area is performed. It is something to do. On the other hand, the "decoding mode" performs high-speed data decoding after the target area is determined.

【0103】

In this flowchart, first, various settings for signal detection are made (step S71). In the fourth embodiment, it is assumed that the frame rate for capturing the entire screen is 10 fps.

【0104】

FIG. 32 is a timing diagram in the detection / capture mode. (A) shows the brightness fluctuation of the light P output from the light emitting unit 301, (B) shows the sampling level received (imaged) by the light receiving unit 40, and in the figure, ts is the shutter time in the signal acquisition mode. .. In synchronization with the brightness fluctuation in (A), the light receiving unit 40 side receives light at the timing and shutter time indicated by the horizontal arrow. The shutter time in the light receiving unit 40 is set so that the shutter time is lengthened and the aperture and gain in imaging are set so that an integral effect is obtained with respect to the fluctuation of the transmission bit of the light emitting unit 301. When ts is set to 50 (ms), for example, 32 bits of OFF-ON (L) are observed on the light receiving unit 40 side and integrated to calculate the average luminance value of the signal fluctuation. In this way, in the detection / supplement mode, the fluctuation of the coordinates in which the corresponding signal exists in the angle of view is observed as the fluctuation as shown by the dotted line in (B) as a result.

【0105】

FIG. 33 is a timing diagram in the decoding mode. (A) shows the brightness fluctuation of the light P output from the light emitting unit 301, (B) shows the sampling level received (imaged) by the light receiving unit 40, and in the figure, ts is the shutter time in the signal acquisition mode. .. In the figure, the light receiving unit 40 receives light in synchronization with the brightness fluctuation of the transmission data bit waveform on the light emitting unit 301 side.

【0106】

In FIG. 31, when the read clock setting for the detection / capture mode and the read area range setting are completed as the initial settings (step S71), then the same frame buffer registration process as in step S21 is performed (step S72), and step S24. Performs the same display processing as in (step S73). Next, it is determined whether or not the time-series image for one pattern cycle is stored in the frame time-series buffer 52 (whether or not the buffer pointer = N) (step S74), and the determination result is NO. For example, while returning to step S72, if the determination result is YES, the signal detection process, that is, the luminance fluctuation detection process by the light P is executed (step S75). Then, the presence / absence of signal detection is determined (step S76), if there is no signal detection, the process returns to step S72, and if there is, the detection mark frames are overlapped (step S77) and then tapped on the detection mark frame area. When an operation or the like is detected (step S78), the process proceeds to the decoding mode process (step S79 to step S84).

【0107】

In the decoding mode processing, first, the brightness fluctuation detection area is set and the frame rate is set (step S79). The frame rate in the fourth embodiment is set to 64 times the rate at which the entire angle of view is imaged.

【0108】

Step S80 is a loop process in which motion correction is performed for an area of 16 transmission bits and the level of the center dot is observed. Next, the threshold level is determined in order to move to the subsequent steps S81 to S84.

【0109】

FIG. 34 is a conceptual diagram for determining the threshold level. The figure shows the temporal luminance fluctuation in the decoding mode, the level on the vertical axis is represented by the dynamic range of 256 steps in the 8-bit quantization model, and the waveform D is the baseband in the intermediate region between levels 80 and 105. If detected as a waveform, the threshold level is set to 130 (maximum) -80 (minimum) / 4 + 80 (minimum level) = 92.5.

【0110】

Based on the threshold level determined in this way, the data in the read area range is taken out, motion correction processing is performed by comparison processing with the previous time, and the sample dot coordinates to be detected are determined (step S81). Then, the data is logically determined at the threshold level determined in step S80, the source data bit string is extracted for each bit, and the decoding process is performed (step S82).

【0111】

FIG. 35 shows a conceptual diagram of the logic judgment, and a case where the transmission data level is judged based on the determination of the threshold level in FIG. 34, where the logic signal 0 is below the threshold level and the logic signal 1 is above the threshold level. Shown.

【0112】

Finally, in response to the user's operation (specific key operation, etc.), it is determined whether or not to exit the decoded data display mode and shift to the signal detection / acquisition mode for the entire angle of view (step S84). ), Ends a series of processes.

【0113】

As described above, in the fourth embodiment, the modulation for detection and the modulation for information transmission (baseband modulation) are superimposed, and the brightness fluctuation is set to "OFF", "ON (L)", and "". Since it is set to "ON (H)", it is a simple and high-speed signal detection method that is resistant to disturbance, and it is possible to transmit and reproduce a good information character string even if the brightness fluctuation is detected in a small area.

【0114】

Further, in the detection / capture mode, by acquiring the area image data in advance and performing motion correction by the correlation between the frames, good detection performance can be ensured even if there is a fluctuation such as camera shake.

【0115】

In the detection / capture mode, the decoding mode is entered for each area specified by the user, but if the configuration allows reading by specifying multiple areas, one frame rate period. Data can be transferred for multiple areas within the same time. Therefore, it is also possible to configure an apparatus that simultaneously performs decoding processing for a plurality of regions at the same time by reading a plurality of partial data of each region at a frame rate and shifting to the decoding mode.

【0116】

Further, in the fourth embodiment, baseband modulation is adopted in the decoding mode, but code diffusion modulation can also be used. In this case, it is possible to make it extremely resistant to sensor detection noise and fluctuations in imaging conditions.

【0117】

[Effect of the invention]

According to the present invention, light modulated by two bit pattern sequences is emitted from the light emitting unit, and the information contained in the light is decoded by the light receiving unit. Specifically, the light emitting unit logically determines a bit string constituting information to be transmitted, and selectively determines a bit pattern sequence from two bit pattern sequences having a low degree of correlation with each other prepared in advance according to the determination result. A selection is made, and an optical signal is output with an intensity modulated according to the selection result. The light receiving unit binarizes the received optical signal according to the intensity, and the bit pattern sequence included in the binarization result is When corresponding to any one of the two bit pattern sequences having a low degree of correlation with each other prepared in advance, the corresponding logic signal is generated to reproduce the information. As a matter of course, even if there is a change in brightness, it is possible to always correctly extract information by avoiding the adverse effect of ambient light that does not have regularity as in the two bit pattern sequences. Further, since one bit is made into a pattern of several time series and detected by paying attention to the correlation, high noise resistance can be obtained even if the fluctuation range on the light emitting side is small. Further, when the bright spot image and its information are displayed on the liquid crystal display together with the subject image, the visibility of the information is impaired as the number of bright spot images increases. To avoid this, on the display screen. Information may be displayed only for the bright spot image located in a specific part (for example, the central part of the screen). Further, if one logic of the two bit pattern sequences is inverted to form the other bit pattern sequence, the generation circuit of the bit pattern sequence can be made into a single configuration, and the circuit configuration can be simplified. be able to. In addition, the original image is divided into several areas (read area range), each area is scanned, and if an n-bit code is detected in a specific area, n times for the read area range. By performing partial readout, it is necessary to increase the amount of data transfer and reduce the amount of data to be handled while capturing changes in brightness in a small area (decreasing the number of pixels). The demands can be satisfied at the same time. Further, by using a low resolution area at the beginning of scanning, the time for initial acquisition can be shortened. In addition, by setting the light source fluctuation to "OFF", "ON (L)", and "ON (H)", detection with strong environmental resistance, simple and high-speed signal detection, and high-definition detection (imaging) (Detection of a light source, which is a small area area on the data) can be satisfied at the same time.

[Simple explanation of drawings]

[Figure 1]

It is a conceptual block diagram of a light emitting unit 1.

[Figure 2]

It is a figure which shows an example of a pattern series (SA / SB), and is a block diagram when two pattern series (SA / SB) are made at the same time.

[Fig. 3]

It is a conceptual block diagram of a light receiving unit 20.

[Fig. 4]

It is a front perspective view of a light emitting unit 30, a front perspective view of a light receiving unit 40, and a rear perspective view of a light receiving unit 40.

[Fig. 5]

It is an electric internal block diagram of a light emitting unit 30 and a light receiving unit 40.

[Fig. 6]

It is a figure which shows the use example of a light emitting unit 30 and a light receiving unit 40.

[Fig. 7]

It is a figure which shows the flowchart of the light emission processing program executed by the CPU 36 of a light emitting unit 30.

[Fig. 8]

It is a figure which shows the timing chart of the light emitting operation of a light emitting unit 30.

[Fig. 9]

It is a figure which shows the timing chart of the light emitting side (light emitting unit 30 side) and the light receiving side (light receiving unit 40 side).

[Fig. 10]

It is a figure which shows the flowchart of the light receiving processing program executed by the CPU 49 of the light receiving unit 40.

[Fig. 11]

It is a figure which shows the flowchart of the frame buffer registration processing subroutine program.

[Fig. 12]

It is a figure which shows the flowchart of the signal detection & bit extraction processing subroutine program.

[Fig. 13]

It is a figure which shows the flowchart of the list update processing subroutine program.

[Fig. 14]

It is a figure which shows the flowchart of the display processing subroutine program.

[Fig. 15]

It is a conceptual diagram of camera shake correction in a frame buffer registration processing program.

[Fig. 16]

It is a conceptual diagram of the correlation degree calculation in a signal detection & bit extraction processing program.

[Fig. 17]

It is an example figure of the state of the data list memory 55 after executing the list update processing program.

[Fig. 18]

It is a figure which shows another example of a light receiving unit 40.

[Fig. 19]

It is an electric internal block diagram of the light receiving unit 40 in 2nd Embodiment.

[Fig. 20]

It is a conceptual diagram of the read area range and the figure which shows the boundary line of the read area range when it does not overlap.

[Fig. 21]

It is a figure which shows the overall operation flowchart of the light receiving unit 40 in 2nd Embodiment.

[Fig. 22]

It is a conceptual diagram which shows the correspondence relationship between the original image (image of 1280 × 960 dots) and the read area range (320 × 240 dots).

[Fig. 23]

It is an electric internal block diagram of the light receiving unit 40 in 3rd Embodiment.

[Fig. 24]

It is a conceptual diagram which shows the storage data of a read condition list memory 112.

[Fig. 25]

It is a figure which shows the scan image corresponding to the condition number (No. 1 to No. 5) of the read condition list memory 112.

[Fig. 26]

It is a figure which shows the overall operation flowchart of the light receiving unit 40 in 3rd Embodiment.

[Fig. 27]

It is an electric internal block diagram of the light emitting unit 301 in 4th Embodiment.

[Fig. 28]

It is a figure which shows the operation flowchart of the light emitting unit 30 of 4th Embodiment.

[Fig. 29]

It is explanatory drawing of DC component removal which removes the bias (DC component) of a bit of "1" and "0" from a bit string of arbitrary data.

[Fig. 30]

It is a figure which shows the luminance fluctuation pattern.

[Fig. 31]

It is a figure which shows the overall operation flowchart of the light receiving unit 40 of 4th Embodiment.

[Fig. 32]

It is a timing diagram at the time of a low frame rate.

[Fig. 33]

It is a timing diagram at the time of a high frame rate.

[Fig. 34]

It is a conceptual diagram for determining the threshold level.

[Fig. 35]

It is a conceptual diagram of a logical judgment.

[Explanation of symbols]

P light 1 Luminous unit 2 Logical judgment unit (judgment means, selection means) 5 Drive unit (modulation means, output control means) 20 Light receiving unit 21 Light receiving part (binarization means) 22 Pattern sequence determination unit (bit pattern determination means) 23 Logic signal 1 generator (signal output means, reproduction means) 24 Logic signal 0 generator (signal output means, reproduction means) 30 Luminous unit 40 Light receiving unit (imaging device) 43 Shutter key (instruction means) 44 Liquid crystal display (display means) 45 Imaging unit (imaging means) 49 CPU (binarization means, bit pattern determination means, signal output means, reproduction means, scanning means, division means, changing means, subsampling means, area selection means, display control means) 301 Luminous unit