Extended working range dataform reader including fuzzy logic image control circuitry

Cross-reference to related applications This application is filed on July 25, 1995 with concurrent application Nos. 08 / 507,607 and June 26, 1995 with concurrent application Nos. 08 / 494,435. It is a partial continuation application of the simultaneous application No. 08 / 332,592 filed on October 31, 1994 and the simultaneous application No. 08 / 280,489 filed on July 16, 1994. Each application is cited in its entirety in this document. Technical Field The present invention relates to a data form reading device and a method for reading a data form composed of 1D and 2D barcodes and a matrix code. More specifically, the fuzzy logic image control circuit is used to reduce the time required to adjust the exposure control parameters and signal processing parameters, and the gain is appropriately adjusted, which is optimal for correctly exposed decoding. It relates to a data form reading device and a method for reading a data form including a data form reading module constituting a composite video image. Background of the invention A. The applications and uses of data-type background barcodes and matrix codes are well known and are steadily increasing. A barcode and a matrix code are one form of a "data form" and are defined here to include all configurations. This locks the data in some form of machine-readable copy. Thus, the data forms include one-dimensional (1D) barcodes, two-dimensional (2D) barcodes (eg UPC, C128, PDF417, etc.) and matrix codes (eg MaxiCode, data matrix, code). One (Code 1) etc.) and graphic codes are included, and like words, numbers and other symbols, they are printed or etched on paper, plastic cards, metal parts, etc. Data forms can be printed with invisible ink, magnetically recorded via magnetic pieces or magnetic ink fonts, electromagnetically recorded via RF tags, engraved, stamped, etc. (on silk). Inked, formed by ion doping (for semiconductor wafers), or formed by biochemical bonds. When utilizing the data form, the initially encoded data is restored in various ways for the next use. For example, the printed barcode is optically scanned, digitized and stored in buffer memory, and the decoded reflectance value is extracted to restore the barcoded data. Regardless of the particular type of data form, the image is generally stored as a pixel value for post-acquisition processing. An image in barcode or matrix code format that exists as a graphic image has a charge coupling element (CCD) that can identify different reflection values of the light-reflected data cell and synchronize the data cell format with a specific data form. Obtained using a reading device or an appropriate device such as a laser scanner. For example, a barcode generally consists of black or dark bar-shaped elements printed on a white or light background area with white or light color spacing between the elements of the barcode. .. The spacing is generally the same color as the background area, but may be a different light color in this example. In another example, barcode or matrix code elements are white or light in color and are defined by black or dark color spacing and background areas. Further, in an application example such as laser engraving on a silicon wafer, illumination establishes a dark color relationship on a bright color in one direction and a bright color relationship on a dark color in another direction. .. In addition to pixel values representing the reflection value of light (light is defined here to include the entire electromagnetic spectrum), as in another configuration, a data form of the appropriate configuration of a medium such as a sound wave. There is also a pixel value that represents the reflection value based on the reflection from. In the case where the data form is configured and read based on the reflection value, the reflection value is generally stored as a pixel value in a storage medium such as an image buffer memory in the form of a bitmap or the like. Bitmaps and other forms represent images in pixel values, but may also use an appropriate data storage format. B. Background of data type readers Conventional technology portable terminals equipped with an integrated laser barcode scanner module or a 1D CCD barcode reader module are not very suitable for reading 2D barcode data types. Laser barcode scanners project a narrow laser beam that forms an intensely illuminated spot on the barcode. By vibrating the mirror continuously, the direction of the laser beam is changed so that the spot moves in a sweep pattern or a raster pattern. In general, the sweep pattern is associated with the vibration of the beam in the horizontal axis direction without vertical vibration. The raster pattern is associated with high-speed vibration in the horizontal axis and low-speed vibration in the vertical axis, and looks like a sweep pattern that moves up and down. The photodetector collects illumination from the entire target area. When a moving or flying (flying) spot is incident on a large part of the barcode reflection such as a white background, the light reflected from the spot is incident on the optical sensor. When the flying spot is incident on a less reflective part of the barcode, such as a black bar, the light is less reflected towards the photodetector. The laser scanner does not have an internal synchronization mechanism. The laser scanner calculates the relative horizontal position of the laser spot based on a well-known self-synchronizing pattern in 1D barcode format. This is called the code self-synchronization method. The raster pattern laser scanner can read 2D storage barcodes such as PDF-417. This is because PDF-417 consists of specific column indication patterns that are recognized and used by scanners for vertical synchronization. With this method, the tolerance of rotation angle is very small. This means that the scanner will row if the spot does not sweep the entire pattern. This is because the code work pattern such as the indicator) pattern cannot be recognized. Laser scanners cannot read 2D matrix codes such as maxi codes and data matrix code formats. This is because these codes do not include column indication patterns for vertical synchronization. The 1D CCD reader captures a long, thin target area on a 1D photodetector array rather than scanning the illumination spot across the bar code symbol. If the reader is positioned relative to the 1D barcode so that the captured target area fits over a relatively large area of the barcode, the barcode will be from the pixels where each bar and spacing of the code is imaged. It is decoded based on the run-length sequence of the extracted gradation value. Like the laser scanner, the 1D CCD does not perform vertical synchronization, so it has to rely on the column indication pattern for vertical synchronization. More recently, the concept of CCD readers has been expanded to 2D CCD readers such as the TEC contact reader manufactured by Tokyo Electric Power Company. The 2D CCD reader images the target area on a 2D array of photodetectors and optical sensors. Such devices can also read matrix codes because the 2D pixel array allows both horizontal and vertical synchronization. This reader is too large and bulky for practical use in portable terminals. Moreover, it consumes too much power for battery-powered portable devices. The conventional 2D CCD reader is an image capture system (image capture). system) is provided. The image capture system consists of a doard camera that continuously generates a composite video signal that represents the target area. When the read period begins, a portion of the signal is selected and decoded. Since the plate camera continuously generates a video signal, it consumes about 1 to 2 watts of power. This consumption consumes a typical battery in less than an hour of operation. Currently, state-of-the-art image capture configurations do not address plate cameras that are suspended until the next reading period. Currently available plate cameras have a wait time of 600 milliseconds (ms) to generate a properly exposed composite video signal with gain correction after power-on, i.e., to reach equilibrium. Needs. The latency consists of the time required to synchronize the readings of the optical sensor and the time required to adjust the gain control / exposure period via the closed-loop analog feedback circuit. Therefore, if each reading period requires the plate camera to be turned on, the reading period will inevitably be longer than 600 ms. Consumers expect short response times, so it is highly desirable that the total read period be less than 300ms. Therefore, with current equipment, the plate camera cannot be stopped until the next data shape reading period. Conventional exposure control systems use separate analog integrated circuits that receive analog video signals from an optical sensor array, generate individual voltage signals, and control gain, exposure period, and reference voltage. The closed-loop analog system provides linear adjustment to the exposure parameters (gain, exposure period, and reference voltage). This is highly desirable for eliminating steep fluctuations in the composite video signal. However, such a closed-loop analog system is not desirable in a data type reading device in which a steep fluctuation of a video signal is desired in order to construct an image that can be decoded as fast as possible. Therefore, there is a need for a 2D imaging type data type reader module that can be turned off until the next data type reading period. Inevitably, the reader module has a response time Is short. That is, there is a short latency between powering on and generating an exposed composite video image with gain adjusted to suit decoding. In addition, a reader module that keeps power consumption low during power-on is required. Further, there is a demand for a data type reader module that is provided with an image control circuit that adjusts the exposure period setting and the gain setting of a plate-shaped camera at high speed to form a composite video image capable of decoding. Further, an image control circuit that generates a high reference voltage value and a low reference voltage value used when adjusting the gain setting and the exposure period setting is required. Further, in order to avoid undesired steep fluctuations in the composite video signal, an image control circuit that gives linear adjustment to the gain setting and the exposure period setting is required. In addition, a portable data collection system composed of such a data type reader module is also required. It is desired that this system is small and lightweight, has low power consumption, and overcomes the drawbacks of conventional devices. Description of the Invention According to the present invention, a portable CCD data reader module having a size and shape comparable to that of a conventional laser scan module is provided. The reader module of the present invention comprises a control / decoding substrate electrically connected to a camera assembly including a plate camera. The control / decoding board is provided with a fuzzy logic image control circuit connected to the plate-shaped camera in a closed-loop feedback configuration. The plate-shaped camera produces a video image of a target area having a data shape. A video image is composed of a series of image frames. One frame consists of two interlaced fields. One field is created by reading the charge stored on the two-dimensional array of optical sensors. The exposure period of the plate camera is shorter than the time required to read the charge on the optical sensor array. The plate camera produces a "raw" analog voltage signal that corresponds to the video image. The "raw" analog signal is amplified by the plate camera gain circuit. The gain-adjusted analog video signal is sent to the fuzzy logic image control circuit. The image control circuit is The in-tuned video signal is analyzed to generate a control signal to be sent to the plate camera. Then, the gain setting and the exposure period setting of the plate-shaped camera are controlled so that the camera can generate the optimum video image for decoding. Depending on the speed at which the fuzzy logic image control circuit analyzes the captured frame of the video image and, if necessary, adjusts the gain and / or exposure time of the plate camera, the reader module of the present invention has a changing lighting environment. Can be adapted immediately. Moreover, the reader module of the present invention can be immediately adapted to the new lighting environment as soon as the module is powered on. This feature allows the exposure parameters to be instantly adjusted to the lighting conditions, allowing the reader module to remain off until the next data form reading period. By turning off the reader module until the next reading period, the power consumption of the module can be kept considerably lower than that of the conventional CCD reader module. As mentioned above, the conventional CCD reader module has a feature that the response time from the time when the power is turned on to the time when the optimum video image for decoding is obtained is an unacceptable length (600 ms). , In general, the power cannot be turned off until the next read period. The reader module of the present invention thus increases the effective operating time until the next battery replacement and / or the effective operating time until the next recharge of the conventional CCD reader module in the power-on state. increase. The fuzzy logic image control circuit of the present invention is composed of a fuzzy logic control unit, a signal processing circuit, a D / A converter, and an A / D converter. The image control circuit receives the gain-adjusted video signal output by the plate camera and captures the signal portion for a period of time corresponding to one video image frame. This signal is input to the A / D converter together with the high voltage reference value and the low voltage reference value. The A / D converter digitizes the gain-adjusted video signal and converts the obtained digital voltage signal into a series of gradation values. Fuzzy logic image control of the present invention The range of gradations used by the circuit is from 0 (black) to 255 (white). The plate camera comprises a 752 x 582 optical sensor array consisting of 437,664 optical sensors. The optical sensor produces a video image consisting of 437,664 pixels. The captured video image frame is therefore composed of approximately 437,664 pixels that vary in intensity or brightness according to the captured video image. The portion of the gain-adjusted video signal that corresponds to the captured frame represents the pixel intensity associated with that frame. The signal is a series of 437, Converted to 664 corresponding gradation values. The gradation value is input to a signal processing circuit that obtains three values based on the gradation value. The three values are the intensity value (I), the maximum dynamic range (DRMAX), and the minimum dynamic range (DRMIN). The I, DRMAX and DRMIN values are input to the fuzzy logic control unit. The fuzzy logic control unit has three empirically derived attribution function charts (membership functions) stored in memory. Calculate the index change value using charts), I, DRMAX, and DRMIN values. The fuzzy logic control unit calculates the corrected index value by adding the calculated index change value to the current index value. The fuzzy logic controller then accesses the empirically derived reference table stored in the memory to a) set the gain of the plate camera and b) of the plate camera based on the correction index values. Make sure that the exposure period and c) the high reference voltage value and d) the low reference voltage value are "correct" values. The "accurate" setting for the gain setting and the exposure period is a value empirically determined to realize a plate camera that produces a video image suitable for decoding the data form. The fuzzy logic control unit compares the current index value with the modified index value. If the two index values are "approximate", that is, if the difference between the values is within a predetermined range, the captured video image is suitable for decoding and then decoded by the decoding circuit. To. If the two index values are not "approximate", the fuzzy logic control system generates a digital control signal corresponding to the "accurate" setting of gain and exposure period. The digital control signal is converted into an analog signal by the D / A converter and sent to the gain circuit and exposure period circuit of the plate-shaped camera, and the plate is matched with the confirmed "accurate" gain setting and exposure period setting. The gain and exposure period of the analog camera are adjusted. The predetermined "approximate" range depends on the index value and is empirically determined. Conceptually, if the difference between the current metric and the modified metric deviates from the predetermined range associated with the current metric, then the captured video image frame is not suitable for decoding. , Another frame is captured and analyzed to determine if the newly captured frame is suitable for decoding. Before capturing a new frame, the fuzzy logic control system generates a control signal sent to the plate camera to adjust the gain setting and the exposure period setting according to the previously determined "accurate" value. The analysis process is repeated each time a new video image frame is captured. Newly captured video image frame An "accurate" high reference voltage value and a low reference voltage value are used for the analysis of the system. Further, according to the present invention, the reader module includes an optical assembly having a large F number. This optical assembly provides an operating range of approximately 2.5 inches to at least 8.5 inches in front of the reader while maintaining a wide field of view. The reader module can capture high signal-to-noise ratio images every less than 0.01 seconds. For this reason, the reading device can tolerate the user's camera shake considerably. The reader module is provided with an efficient, high-intensity uniform illumination module to accommodate high F-number optics and short exposure periods. The high-intensity lighting module is fixed to the front surface of the exterior of the reader module, avoiding the lighting loss problem and internal reflected lighting noise problem associated with arranging the lighting source behind the window inside the exterior of the reader module. ing. The lighting module comprises a printed circuit board assembly consisting of a plurality of surface mount LEDs secured to the front side of the printed circuit board. The substrate is adhered to a recess provided on the back side of the resistant acrylic lens array. The lens array directs uniform and intense illumination towards the target area in front of the reader module. In a preferred embodiment, the illumination module has a central opening and the reader module is arranged to collect the light reflected from the target area through the opening. This configuration ensures that the illumination from the lens array of the reader module matches the field of view of the reader module. According to one aspect of the present invention, the reader module includes a circuit that emulates the output of the laser scan module, and a data type reader including a laser scanner is realized. According to another aspect of the invention, a data acquisition system comprising the reader module of the invention is provided. The data type reading system is intended for portable use and is intended for use in IEEE 802. 11 Equipped with a spread spectrum radio for connecting the reader to the computer via a compatible network. Spectral diffusion radios are used to transmit decoded data form data, compressed captured image data, and compressed data files representing voice messages. Further, according to the present invention, the portable data acquisition system including the data type reader module of the present invention further operates with various circuits to enhance the functionality of the reader module, such as a keyboard and a display. It is equipped with a user interface device such as a touch panel, a microphone, and a speaker. In order to better understand the present invention and another further object, the present invention will be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present invention will be described with reference to the accompanying drawings. The attached drawings are as follows. FIG. 1 is a perspective view of a data reader module of the present invention including a control / decoding board and a cut-out view of the outer skin of a camera assembly. FIG. 2 is a block diagram of selected electronic components of the data reader module of FIG. FIG. 3A is a graph of the attribution function chart of the gradation histogram value. FIG. 3B is a graph of the attribution function chart of the maximum dynamic range. FIG. 3C is a graph of the attribution function chart of the minimum dynamic range value. FIG. 4 is an empirical reference table used to determine the exposure period, gain, high reference voltage value, and low reference voltage value based on the calculated index values. FIG. 5 is a flow chart showing the operation of the fuzzy logic exposure control system of the data type reader module of FIG. FIG. 6 is a top view schematically showing the data type reader module of FIG. FIG. 7 is an exploded perspective view showing the lighting module of the data type reader module of FIG. FIG. 8 is a side sectional view showing a part of the lighting module of FIG. 7. FIG. 9 is a state diagram showing the operation of the power supply control circuit of the data type reader module of FIG. FIG. 10 is a perspective view of a portable data acquisition system including the data type reader module of FIG. FIG. 11 is a side view showing a partial cross section and a partial elevation of the portable data acquisition system of FIG. FIG. 12 is a perspective view showing another embodiment of a portable data acquisition system including the data type reader module of FIG. FIG. 13 is a side view showing a partial cross section and a partial elevation of the portable data acquisition system of FIG. FIG. 14 is a block diagram of the voice mail system of the present invention. FIG. 15 is a front elevation view of the wireless headset system of the present invention. Looking at the detailed explanatory drawings, the data type reader module of the present invention is shown in FIG. 1 with reference number 10. The data reader module 10 consists of a camera assembly 12 and a control / decoding board 14. The control / decoding board 14 includes a microprocessor 16 and a fuzzy logic image control circuit 18. The fuzzy logic image control circuit 18 is realized by software resident in a memory chip 19 of one or more RAMs or ROMs mounted on a board 14, and is operated by a microprocessor 16. Alternatively, the image control circuit 18 comprises a separate application specific integrated circuit (ASIC) mounted on the substrate. As shown graphically in FIG. 2, the image control circuit 18 mounted on the control / decoding board 14 includes a fuzzy logic control unit 20 and a digital-to-analog conversion circuit (D / A converter) 22. It consists of an analog-to-digital conversion circuit (A / D converter) 24 and a signal processing circuit 26. A power supply circuit 28 is also provided on the board 14. The power supply 30 supplies power to the circuits on the board 14. The power supply circuit 28 includes a lead wire 29 connected to the input port 32 of the camera assembly 12 to supply power to the camera assembly. As can be seen from FIGS. 1 and 6, the camera assembly 12 includes a plate-shaped camera 40 in which three printed circuit boards 41a, 41b, and 41c are arranged at intervals. On the upper plate 41a of the plate-shaped camera 40, in order to converge the image light of the object having the 2D optical sensor array 42 and the barcode data shape (not shown), that is, the target field of view 166 (FIG. 6) on the sensor array. Optical assembly 44 and is mounted. The optical sensor array 42 comprises a 752 × 582 optical sensor array. When the reader module 10 is powered on, the optical sensor array 42 becomes 437, Generates a video image consisting of 664 pixels. The optical assembly 44 is supported within an annular camera exterior 46 that covers the optical sensor array 42 to prevent ambient light from reaching the optical sensor. The optical assembly 44 is separated from the optical sensor array 42 by a distance corresponding to the image plane of the optical assembly. Each photosensor in the photosensor array 42 stores the charge generated by photons colliding with the photosensor during the exposure period. The exposure period is shorter than the time required to read out one field of the video image. By reading out the charges stored in each of the 437,664 optical sensors in the optical sensor array 42, one field of video image is constructed. The two interlaced fields make up one frame of the video image. The amount of charge on the photosensor at the end of the exposure period is proportional to the number of photons colliding with the photosensor. The photons that collide with the photosensor are associated with the light reflected from the target area, the image area. The incident light that collides with the target field of view, or target area 166, is generated by the illumination module 47 (not shown in FIG. 1, but shown in FIGS. 7 and 8). The intensity or brightness of each pixel corresponds to the charge of the associated optical sensor. When reading the optical sensor, the charge on each optical sensor is transferred to the storage register. The length of the exposure period is controlled by the exposure control circuit 48 (outlined in FIG. 2) of the plate camera 40. The transferred charge is read from the storage register and an analog voltage signal 50 representing a video image is generated. This "raw" video signal 50 is amplified by the output gain circuit 52 (schematically shown in FIG. 2) of the plate camera 40 to generate a gain-adjusted composite video signal 54 suitable for decoding. The gain-adjusted video signal 54 is an analog signal. The part of the signal 54 that corresponds to one exposure period constitutes a field of video image and during the exposure period 437, Represents a series of charges associated with each of the 664 photosensors. As mentioned above, a frame of a video image consists of two interlaced fields. If the exposure period of the plate camera 40 is too short, most of the charge of the optical sensor of the optical sensor array 42 is insufficient, and the generated data form video image is too dark. Therefore, the gain-adjusted video signal 54 is not suitable for decoding. On the other hand, if the exposure period of the plate camera 40 is too long, the optical sensor of the optical sensor array 42 is overcharged and the generated video image is too bright. Again, the gain-adjusted video signal 54 is not suitable for decoding. If the gain applied to the "raw" video image voltage signal 50 is too much or too little, the gain-adjusted composite video signal 54 is not suitable for decoding. As soon as the reader module 10 is powered on, the plate camera produces a video image of the target field of view. The fuzzy logic image control circuit 18 captures the portion corresponding to the frame of the gain-adjusted video signal 54 and determines whether the captured frame is suitable for decoding the image in the frame. When the fuzzy logic image control circuit 18 determines that the captured frame is suitable for decoding, the frame contents are stored in the memory 19 and then decoded by the decoding circuit 92 (FIG. 2). When the fuzzy logic image control circuit 18 determines that the captured frame is not suitable for decoding, one or more plate camera operation parameters are adjusted by the control signal generated by the image control circuit 18. Another image frame is captured by the image control circuit 18, analyzed, and appropriately decoded. Therefore, the configuration of the reader module 10 provides open loop feedback between the fuzzy logic image control circuit 18 and the plate camera 40. The fuzzy logic image control circuit 18 obtains a video image frame suitable for decoding by iterative processing. The iterative process consists of a capture stage, an analysis stage, and an adjustment stage. That is, the stage of capturing the video image frame and the stage of analyzing the frame and decoding it appropriately. It consists of a step of adjusting one or more plate-shaped camera operation parameters when it is not suitable. The flow chart of FIG. 5 shows this iterative process. For most data-type images, no more than three iterations are required to obtain an image suitable for decoding. That is, you must capture no more than three frames. The high-speed execution of the iterative processing by the fuzzy logic image control circuit 18 makes the waiting time very short. The latency is defined as the elapsed time between turning on the reader module 10 and obtaining a video image suitable for decoding. The waiting time is the time required to synchronize the readings of the optical sensor plus the time required to adjust the gain and exposure period parameters of the plate camera 40. In the reader module 10 of the present invention, a waiting time of 50 ms or less is achieved. Returning to FIG. 2, the gain-adjusted video signal 54 generated by the plate-shaped camera 40 is sent to the input port 56 of the control / decoding board 14. The video signal 54 is decoded by the fuzzy logic image control circuit 18 and subjected to fuzzy logic analysis. Based on fuzzy logic analysis, the control circuit 18 generates analog control signals 58 and 60 to be sent to the input ports 62 and 64 of the control / decoding board 14. The control signal 58 is input to the exposure period circuit 48 to control the exposure period of the plate-shaped camera 40. On the other hand, the control signal 60 is input to the gain circuit 52 to control the gain setting of the plate-shaped camera. The gain-adjusted composite video signal 54 is sent to the A / D converter 24. Two analog reference voltage signals 66 and 68 are also input to the A / D converter 24. The voltage signal 66 is a high reference voltage signal, and the voltage signal 68 is a low reference voltage signal. The fuzzy logic circuit unit 20 generates index values 70 and 72 corresponding to the high reference voltage signal 66 and the low reference voltage signal 68. The index values 70 and 72 are converted into separate analog reference signals 66 and 68 by the D / A converter 22. The A / D converter 24 uses the high reference voltage signal 66 and the low reference voltage signal 68 to adjust the gain of the composite video signal 54 as a series of gradations. Convert to a value. The gradation is a series of achromatic colors with white and black endpoints. The gradation range used by the image control circuit of the present invention is 0 (black) to 255 (white). For a given captured video image frame, one gradation value is assigned to each of the 437,664 pixels. The gradation value corresponding to a pixel is also a relative measurement value of the intensity, that is, the brightness of the pixel. The signal 74 representing the gradation value corresponding to the captured frame is sent to the signal processing circuit 26. The gradation value signal 74 for the captured frame of the video image is composed of a series of 437,664 gradation values. The signal processing circuit 26 extracts the intensity histogram value (I) 76, the dynamic range maximum value (DRMAX) 78, and the dynamic range minimum value (DRMIN) 80 from the gradation signal 74. The I value, DRMAX value, DRMIN value 76, 78, and 80 are input to the fuzzy logic control unit 20. The fuzzy logic control unit 20 uses these values to generate digital control signals 82 and 84 to be input to the D / A converter 22. The D / A converter 22 converts the digital gain control signal 82 and the digital exposure period control signal 84 into an analog gain control signal 58 and an analog exposure period control signal 60. The control signals 58 and 60 are input to the ports 62 and 64, and the gain circuit 52 and the exposure period circuit 48 of the plate-shaped camera 40 are appropriately adjusted. The signal processing circuit 26 determines I (intensity histogram value) for the captured frame. I has a size of 128 or more 437, Represents the number of gradation values in a set of 664 gradation values. The gradation value 128 is just above the midpoint of the gradation range in which 128 is 0 to 255, and is selected as a dividing point. The DRMAX and DRMIN values of the captured frame are also determined by the signal processing circuit 26. When the magnitude of the gradation value is linearly graphed on the XY coordinate system, the magnitude draws an irregular wavy pattern in which "peaks" and "valleys" appear alternately. The DRMAX value is the average value (excluding outliers) of the "peaks" of the wavy pattern at the magnitude of the gradation for the captured video image frame. The DRMIN value is the average value (excluding outliers) of the "valleys" of the wavy pattern at the magnitude of the gradation for the captured video image frame. The I value, DRMAX value, and DRMIN value are input to the fuzzy logic control unit 20. The fuzzy logic control unit 20 calculates the index change value using the I value, the DRMAX value, and the DRMIN value. The fuzzy logic control unit 20 accesses the three empirically derived attribution function charts 110 (Fig. 3A), 112 (Fig. 3B), and 114 (Fig. 3C), and uses the index conversion value formula to index. Derivation of the weighting factor used when calculating the conversion value. Each attribution function Charts 110, 112 and 114 are composed of three partially overlapping Ramp functions. Attribution function Chart 110 is the function h₁(I) and h₂(I) and h₃It consists of (I). Function h₁(I) corresponds to an image frame that is too dark, h₂(I) corresponds to a good image frame, that is, a normal image frame, h₃(I) corresponds to an image frame that is too bright. Attribution function Chart 112 shows the function ma₁(DRMAX) and ma₂(DRMAN) and ma₃It consists of (DRMAX). The maximum dynamic range of a properly exposed image has a gradation value in the range of 150 to 230. ma₁The (DRMAX) function represents an image frame that represents 150 with a maximum dynamic range that is too low, ma₃The (DRMAX) function represents an image frame that indicates 230, where the maximum dynamic range is too high. Attribution function Chart 114 is the function mn₁(DRMIN) and mn₂(DRMIX) and mn₃Consists of (DRMIN). The minimum dynamic range of a properly exposed image is in the range of 20 to 100 gradation values. mn₁The (DRMIN) value represents an image frame indicating 20 where the minimum dynamic range is too low, mn.₃The (DRMIN) function represents an image frame that indicates 100, where the minimum dynamic range is too high. The determined I value is used by the fuzzy logic control unit 20, and the function h that constitutes the attribution function chart 110.₁(I) and h₂(I) and h₃(I) One weighting factor is determined for each. The determined DRMAX value is used by the fuzzy logic control unit 20, and the function ma that constitutes the attribution function chart 112.₁(DRMAX) and ma₂(DRMAX) and ma₃(DRMAX) One weighting factor is determined for each. Finally, the determined DRMIN value is used by the fuzzy logic control unit 20, and the function mn that constitutes the attribution function chart 114.₁(DRMIN) and mn₂(DRMIN) and mn₃(DRMIN) One weighting factor is determined for each. Function h according to the index change value formula₁(I) and h₂(I) and h₃(I),ma₁(DRMAX) and ma₂(DRMAX) and ma₃(DRMAX) and mn₁(DRMIN) and mn₂(DRMIN) and mn₃(DRMIN) Calculate the attribution value using each. Weights are assigned to each function as shown in the following table.<img file="JP3672930B2_D0001.tif" />The empirically derived index change value formula is as follows. Δ index = [7 × Σh₁(I) W _1i] + [1 × Σma₁(DRMAX) W _2i] + [1 × Σmn₁(DRMIN) W _3i] Here, Δ index = chart change value h₁ = H above₁(I) and h₂(I) and h₃Attribution relationship value W for (I)_1i = h₁(I) and h₂(I) and h₃Weighting factor W related to (I)₁₁And W₁₂And W₁₃ma₁ = Ma above₁(DRMAX) and ma₂(DRMAX) and ma₃Attribution value W for (DRMAX)_2i = ma₁(DRMAX) and ma₂(DRMAX) and ma₃Weight factor w related to (DRMAX)₂₁And W₂₂And W₂₃mn₁ = Mn above₁(DRMIN) and mn₂(DRMIN) and mn₃Attribution value W for (DRMIN)_3i = mn₁(DRMIN) and mn₂(DRMIN) and mn₃Weight factor W related to (DRMIN)₃₁And W₃₂And W₃₃After determining the index change value (Δ index), the fuzzy logic control unit 20 calculates the correction index value based on the Δ index value and the current index value according to the following formula. Corrected index value = Current index value + Δ When the power is turned on to the index reader module 10, the corrected index value stored in the memory 19 at the end of the previous read period is the current value for the current read period. It becomes an index value. If no value is stored in memory, the default value, such as 9, is used as the current index value. Based on the correction index values, the appropriate gain setting, exposure period, high reference voltage value, and low reference voltage value are determined using the reference table 100 in the memory 19. Figure 4 shows the reference table 100 derived from empirical data. The first column 102 of the reference table 100 lists the correction index values. As a function of the correction index value, the index value 70 (fourth column) and volt corresponding to the exposure period 104 (second column) in milliseconds, the gain setting 106 (third column), and the reference high voltage value 108 in volt units. The index value 72 (fifth column) corresponding to the reference low voltage value 109 of the unit is listed. As an example of the illustration, as soon as the module 10 is powered on, the first captured frame is analyzed by the signal processing circuit 26 to obtain the following values: I 135,000DRMAX 125DRMIN 10 The above values are X in Attribution Charts 110, 112 and 114₁And X₂And X₃It is shown as. Further, it is assumed that the correction index value at the end of the last read period is 20, and that value is stored in the memory 19. As can be seen from the reference table in Fig. 4, the exposure period of the plate-shaped camera 40 is set to 4 milliseconds and the gain is set to the maximum value when associated with the correction index value 20 at the end of the previous reading period. The high reference voltage is set to a value that matches the index value 70, and the low reference voltage is set to a value that matches the value 10. Attribution relationship With reference to Chart 110 (Fig. 3A), X₁= From the I value of 135,000 (135k), the function h shown below₁(I) and h₂(I) and h₃The attribution value for (I) is obtained. That is, H₁ = 0.7H₂ = 0.3H₃ = 0.0 Attribution relationship For Chart 112 (Figure 3B), X₂From the DRMAX value of = 125, the function ma shown below₁(DRMAX) and ma₂(DRMAX) and ma₃The attribution value for (DRMAX) is obtained. That is, MA₁ = 1MA₂ = 0MA₃ = 0 Attribution relationship For Chart 114 (Figure 3C), X₃From the DRMIN value of = 20, the function mn shown below₁(DRMIN) and mn₂(DRMIN) and mn₃The attribution value for (DRMIN) is obtained. That is, MN₁ = .5MN₂ = .5MN₃ = = 0 The fuzzy logic control unit 20 calculates the index change value as follows by substituting the attribution value and the weighting coefficient derived from the above table. Δ index = 7 × [(-1) (.7) + (0) (.3) + (+1) (0)] +1 × [(-1) (1) + (0) (0) + (+1) (0)] +1 × [(-1) (.5) + (0) (.5) + (+1) (0)] = 7 [-0.7] +1 [-1.0] + 1 [-0.5] = 4.9 + -1.0 + -0.5 = -6.4 Next, the fuzzy logic control unit 20 searches the memory 19 for the correction index value (that is, the index value 22) of the previous read period. The modified index value is calculated by using the index value as the current index value. Then, the fuzzy logic control unit 20 calculates the correction index value according to the following mathematical formula. Corrected index value = current index value + Δ index = 20 + -6.4 = 13. 6 = 14 (rounded to the closest integer) As can be seen from the reference table in Figure 4, given the correction index value 14, the exposure period of the plate camera 40 is diffused from 4 ms to 10 ms. , The gain setting remains at the maximum value, the reference high voltage is raised to a high reference voltage that matches the index value 70 and the current value matches the index value 75 volts, and the reference low voltage matches the index value 10. The current value is maintained. The actual reference voltage value that matches the index value is empirically determined. The fuzzy logic control unit 20 generates digital control signals 82 and 84 (converted to analog control signals 60 and 58 by the D / A converter) and causes the exposure period circuit 48 to change the exposure period to 10 milliseconds. The gain circuit 52 is made to maintain the maximum gain. The fuzzy logic control unit 20 also generates index reference voltage signals 70 and 72 to be sent to the D / A converter. The index reference voltage signals 70 and 72 are converted into a high reference voltage signal and a low reference voltage signal 66 and 68 by the D / A converter 22. The modified index value 14 is overwritten by the previous index value 20 and stored in the memory 19 by the fuzzy logic unit 20. The correction value of the exposure period (10 ms) and the high reference voltage (voltage index value 75) is overwritten by the previous value of 4 ms and the index value 70 and stored in the memory 19. According to another aspect of the present invention, the fuzzy logic image control circuit 18 generates a signal 90 sent to the illumination module 47, and when the correction index value corresponds to an exposure period of 4 ms or less, a set of modules. Disable lighting LDE346. That is, the illumination LED 346 is disabled if the correction index value is greater than or equal to 16 (Fig. 4). An iterative process consisting of capture, analysis and adjustment used by the reader module 10 to construct a video image of the target field of view 166 suitable for decoding, which is shown in FIG. 5, will be described. Step 200 is the first step of powering on the data reader module 10. As soon as the power is turned on, the image control circuit 18 sets the gain, the exposure period, and the high base in step 202. The values of the quasi-voltage and the low reference voltage and the current index value are detected from the memory 19. These parameter values match the last parameter value set used in the previous read period. The retrieved value becomes the initial parameter value used by the reader module 10. The image control circuit 18 generates control signals 58 and 60 sent to the input ports 62 and 64 of the plate camera. The control signal 58 is sent to the plate-shaped camera exposure control circuit 48 to set the exposure period of the plate-shaped camera 40 to the value searched for as the exposure period. Similarly, the control signal 60 is sent to the plate-shaped camera gain circuit 52 to set the gain of the plate-shaped camera 40 to the gain search value. The plate camera 40 uses the searched gain setting and the searched exposure period to generate a gain-adjusted voltage signal 54 that represents a video image of the target data form (step 204). As shown in step 206, the fuzzy logic image control circuit 18 captures the portion corresponding to one frame in the data form image of the gain-adjusted video signal 54. Alternatively, the field may be captured and used for analysis by the image control circuit 18. As described above, the captured frame is divided into two reference voltage value correction parameter value sets and index change values based on the gain setting and exposure period of the plate camera and the corresponding voltage index values by the image control circuit 18. It is used to determine the correction index value (step 208). In step 216, the image control circuit 18 determines whether the difference between the modified index value and the current index value is within a predetermined range. If the difference is within a predetermined range, the captured image is suitable for decoding. If the difference is outside a predetermined range, the image control circuit 18 generates signals 58 and 60 to adjust the gain setting and exposure period to the correction parameter values (step 218). In step 220, the correction index value and the correction parameter value are overwritten by the current index and parameter value existing in the memory and stored in the memory 19. As a result, the modified index value becomes the current index value. Another video picture The image frame is captured (step 206) and the analysis process is repeated (steps 208 and 216). If the difference between the modified index value and the current index value is within a predetermined range, the modified index value and the modified parameter value are overwritten with the current value and stored in the memory 19 (step 222). At step 224, the reader module 10 utilizes a decoding circuit to decode the data form within the captured frame. Finally, the reader module 10 is powered down, saving power until the next read period, as shown in step 226. The reader module 10 of the present invention generally captures one to three image fields before proper exposure is achieved. However, the capture / comparison phase of the circuit is rapid, and the wait time to equilibrium is usually less than 50 ms, even if three image fields are required to be captured. With reference to FIG. 2 again, the control / decoding substrate 14 further comprises a decoding system realized by a code capable of calculation by the microprocessor 16 to decode the data form in the target field of view, that is, the image field of view 166. A data type decoding circuit 92 is provided. For suitable decoding systems, U.S. Patent Application No. 08 / 443,909 and U.S. Patent Application No. 08/456, filed May 17, 1995, It is described as No. 113. The contents of both applications are cited herein for reference. Other well-known decoding systems are also considered by the present invention. The result of the decoding is supplied to other processing circuits (discussed later) via the data transfer links 300 (FIGS. 1, 2 and 6). The control / decoding board 14 further comprises a laser module emulation circuit 94 implemented in code that can be executed by the microprocessor 16. The emulation circuit 94 encodes the decoding result in a standard 1D barcode format such as "Code 39" and outputs a square wave signal that emulates the square wave signal of the laser scanner module that scans the 1D code. .. It should be noted that this feature provides the ability to read a set of data forms consisting of 2D barcodes and matrix codes, yet is electrically compatible with the laser scanner module. When operating in laser emulation mode, a square wave signal is obtained and processed via the data transfer link 300. In yet another embodiment of the reader module 10, the module captures an image of the target field of view, or target area 166, so that the module captures an object in the target area as well as to capture an image of the data form. It is also used for shooting. For example, the operator uses the reader module 10 to take a picture of the damaged product and capture an image of the data form associated with the damaged product. When the captured image is captured, the decoder substrate transfers a digital image such as a bitmap of the image via the data transfer link 300. Figure 6 shows the camera assembly 12 with microprocessor 351 and a data transfer link 300 and ancillary circuitry to perform functions integrated into the above camera assembly such as open loop gain control, open loop exposure control, and decoding. It is a top view of the outer skin cut. The performance of the data reader module 10 is enhanced by providing an optical system 302 with an optical assembly 44 with an extended operating range. Optical assembly 44 and optical sensor Based on the position between the subassembly 42 and the target field of view, that is, the best focal position S2, which is the position where the image of the target in the target field of view 166 is most sharply visualized on the optical sensor array 42, is in front of the optical assembly 44. Exists. The quality of the image gradually deteriorates as the subject moves to the near cutoff distance S1 and the far cutoff distance S3. The optical assembly 44 provides each field of view 168 large enough to image a large data form in the far field S3 and generate a large image of the small data form in the near field S2. In a preferred embodiment, the optical assembly 44 has a best focal length of 5.5 inches and an operating range of approximately 2.5 inches to at least 8.5 inches from the anterior surface of the optical assembly. Preferably, the field of view is 8.5 inches away from the anterior surface 186 of the outermost lens 182 and coincides with a target area 5 inches long and 3.75 inches wide, ie target surface 5. The optical system 302 that satisfies these requirements has a left-right symmetrical lens structure. Two nearly identical lenses 182 and 184 are mirrored around the aperture 190. The surface 186 of the lens 182 is large enough to be defined as a flat aspherical surface with a radius of curvature of 1.5298 mm, a conic section constant of -0.019890, a 6th aspherical deformation coefficient of 0.0096, an 8th order coefficient of 0.0057, and a 10th order coefficient of 0.0023. It is an aspherical surface with a coefficient and shape. The rear surface 188 of the lens 182 is a spherical surface with a radius of curvature of 1.6004 mm. Aperture 190 is 0.3606 mm wide between lenses 182 and 184 that make up the optical assembly 44 with an F-number of 13. The diameters of lenses 182 and 184 are not important in the present invention. Details of the optical system 302 of the present invention are described in US Patent Application No. 08 / 494,435 approved by the same designated agent as the present invention. U.S. Patent Application No. 08/494, The content of issue 435 is quoted in its entirety for reference. The optical system 302 is a portable data collection system 400 (examples of the portable data collection system of the present invention are shown in FIGS. 10 and 11. Further, a second embodiment of the portable data collection system of the present invention is shown in FIG. The reader module 10 should be lightweight and impact resistant, as it is used in (shown in 12 and 13). In a preferred embodiment, the optical material used in the manufacture of lenses 182 and 184 is a synthetic of plastic. The use of plastic optical components reduces the weight of the optical system 302 by approximately 60% compared to comparable glass assemblies, yet provides a more impact resistant system. Another advantage of using plastic optics is that the cost of sharpening the aspheric surface of the glass lens can be avoided. The aspherical surface can be easily formed by molding a plastic lens. Although the above-mentioned optical system 302 provides desired attributes, other optical components having similar performance characteristics are known to those skilled in the art. Since the F number of the optical system 302 increases (5.6 or more) depending on the desired operating range and field of view of the reader module 10, the illumination module 47 receives a sufficient amount of reflected light by the optical sensor array 42 and is appropriately used. The target field of view 166 must be properly illuminated during the exposure period to produce a bright video image. However, the exposure period is necessarily limited to .01 seconds or less (see Figure 4) to reduce the effects of operator camera shake during the reading period. The exposure period of .01 seconds or less is shorter than that of a conventional CCD reader. Therefore, the illumination module 47 of the reader module 10 must be properly illuminated to accept large F-numbers and short exposure times. Correct exposure of the sensor array 42 requires a target field of view illuminance of 0.3 lux if the exposure period is .03 seconds and the F number is 1.2. Exposure period 0. The following equation is used to determine the appropriate target field illuminance for 01 seconds and F-number 13. (Illuminance) (Exposure period) / (F number)²= Constant Therefore, the minimum required target field illuminance of the reader module 10 of the present invention is 106 lux at the far field cutoff distance S3. With reference to FIG. 7, which is a perspective exploded view of the illumination module 47, it can be seen that the module consists of a lens array 324 and a printed circuit board assembly 340. The printed circuit board assembly 340 consists of a plurality of surface mount illumination LEDs 346 secured to the printed circuit board 354. The printed circuit board 354 is composed of a printed conductor and a power lead wire 372 for supplying power to the illumination LED 346. The best surface mount lighting LEDs are MarkTech from Latham, NY as part number MTSM735K-UR or MTSM745KA-UR LEDs. Manufactured by Corp.). Each illuminated LED 346 provides 285 mini candela (mcd) illuminance over an approximately 68 ° angular illumination field. Twelve small pedestals for the lighting LED 346 are arranged in a horizontal row with a length of 1.5 inches or less. The printed circuit board assembly 354 consists of a total of 24 double-row illuminated LEDs 346 that are uniformly illuminated at 6840 mcd over a 68 ° field of view. The lens array 324 is composed of a plurality of illumination lens cells 330 aligned in correspondence with the illumination LED 346. The exposure illumination lens cell 330 directs a 68 ° illumination field from each illumination LED 346 to a smaller uniform illumination field that matches the field of view 168 (approximately 50 °) of the optical assembly 44. With reference to FIG. 8, which shows a cross section of the assembled illumination module 47, it can be seen that each illumination lens cell 330 has an internal lens surface 342 and a focal point 380. By installing the illumination LED 346 between the focal point 380 and the internal surface 342, the lens cell 330 acts as a light directing element rather than an image sensor. This avoids the formation of hot spots in the target field of view 166 and provides a very uniform illuminance. The 68 ° illumination field from each illumination LED 346 is collected by each illumination lens cell 330 and directed to a field of view that matches the optical system field of view 168 smaller than 68 °. Further, since the fields of view of the exposed illumination lens cell 330 partially overlap, "crosstalk" occurs between the illumination LEDs 346, and illumination from two or more proof LEDs is directed to the same part of the target field of view 166. Over the field of view 168 of the optical assembly, with illumination of 6840 mcd supplied by the illumination LED 346, far-field cutoff distance 8. At 5 inches (S3 in Figure 6), a lighting intensity of over 106 lux can be obtained. Returning to FIG. 7, the two target setting lens elements 334 positioned on the two target setting LEDs 347 project two pencil-shaped target setting illuminations 307, and the target area at an angle corresponding to the optical system field of view 168. A hot spot is formed in (Fig. 6). Since the hotspot is visible to the operator, it is easy to position the portable data acquisition system 400 (FIGS. 10-13) so that the target data form (not shown) is within the field of view 168 of the optical system 302. The lens array 324 forms the front surface of the lighting module 47 that protects the printed circuit board assembly 340 from physical shock and environmentally harmful elements such as dust and moisture. Therefore, the lens array 324 is preferably molded from an optimal material such as impact resistant acrylic which has the high illumination transmittance and resistance required in the environment for operating the portable data acquisition system of the present invention. Adapted to further protect the printed circuit board assembly 340 from environmentally harmful elementsA coat may be applied to the substrate assembly 340 and the assembly may be glued with a cynoacrolate UV curable adhesive or chemical structural adhesive to the indentation formed on the back surface of the lens array 324. Referring to FIGS. 1 and 7, the lighting module 47 is the front surface of the camera exterior 46 by inserting four screws into the four holes 357 of the lighting module and screwing them into the coaxially aligned holes 359 of the camera exterior 46. Is stuck to. Since the reader module 10 is configured for use in the portable data collection system 400, the module is equipped with a power saving circuit operated by a manually activated two-position trigger 416 (FIGS. 10-13). There is. The trigger may be a two-position trigger (release position and pull-in position) or a three-position trigger (release position, first position and second position). The circuit controls the operation of the plate camera 40 and the lighting module 47 during the reading period. FIG. 9 is a state diagram showing a power supply control circuit. In the off state 228, no power is supplied to the lighting module 47 or the plate camera 40. When the three-position trigger is pulled into the first position, the reader module 10 moves to the target setting state 230. In the target setting state, the microprocessor 16 activates the target setting LED 347, and the plate camera 40 and the illumination LED 346 are off. When the three-position trigger is pulled into the second position, module 10 is in the data form read state 232. The data form reading state is composed of two quasi-states, that is, an exposed state 234 and a decoding state 236. In the exposed state 234, the target setting LED 347 is turned off and the illumination LED 347 and the plate camera 40 are started. After capturing the image, module 10 is in decoding quasi-state 236. In this state, the illumination LED 346 and the plate camera 40 are off. On the other hand, the target setting LED 347 is on, which makes it easier for the operator to hold the reading system 400 in the correct position if image capture and decoding are unsuccessful. If the decryption is successful, the reader module 10 returns to the off state 228. When the trigger is released, the reader Module 10 returns to the target setting state 230 and the off state 228. The timeout causes module 10 to return to the off state without a successful decryption. If the data acquisition system 400 has a two-position trigger, module 10 can operate according to two embodiments. In the case of the first embodiment, the trigger pulls the module 10 into the target setting state 230. When the trigger is released, the system will be in the data form read state 234. In the exposure quasi-state 234 and the decoding quasi-state 236, the operation is the same as in the case of the three-position trigger embodiment. When a timeout occurs, module 10 returns to the off state. Alternatively, the trigger pulls module 10 into a fully automated read state 238. Module 10 automatically stays in the target setting quasi-state 230 for a while and then goes into the data form reading state 232. The operation in the data form reading state is the same as in the above embodiment. Upon release of the trigger, module 10 returns to the off state 228. 10 and 11 and 12 and 13 show two examples of the portable data collection system 400 according to the present invention. The same reference number indicates the same part in the two embodiments. In the case of the portable data collection system 400 shown in FIGS. 10 and 11, the system consists of a pistol-shaped exterior 410. The exterior 410 comprises an upper portion 412 forming the upper container and a handle portion 414 extending below the upper portion 412. Exterior 410 is constructed of optimal impact resistant plastic that provides both resistance and light weight. The two-position trigger switch 416 is appropriately mounted and is used to output a signal to initiate a data read period. The display screen 432 covered with the plurality of key switches 422 and the touch panel 444 can be seen from the opening of the upper portion 412 on the operator side. The portable data collection system 400 shown in FIGS. 12 and 13 is composed of a substantially rectangular exterior 410 configured to be held in the palm of the operator. Multiple key switches 422 on the upper 412 of exterior 410 to be operated by hand holding the data acquisition system 400 It is positioned in. What can be seen from the opening of the upper portion 412 is the display screen 432 covered with the touch panel 444. The exterior 410 is constructed of optimal impact resistant plastic that is both resistant and lightweight. The multi-position trigger switch 416 for initiating the data form read period is centrally located on the upper 412 and allows the operator's thumb to start the read period. With reference to FIGS. 11 and 13, which are cross-sectional views of the portable data acquisition system 400 of FIGS. 10 and 12, each system consists of a camera assembly 426 and a control / decoding board 456 electrically connected to it. It can be seen that the reader module is provided. The camera assembly 426 is located inside the exterior 410, just behind the front side 418 of the exterior. The lighting module 428 is mounted on the front side 418, and the camera assembly exterior 464 projects from the opening 417 of the front side 418 and the opening of the lighting module 428. A seal (not shown) is attached around the nose of the camera assembly exterior 464 to provide an airtight seal between the exterior and the system exterior 410 to prevent dust and moisture from entering the system exterior through the opening 417. Form between. In a preferred embodiment, the control / decoding board 456 is provided with a microprocessor 413 for further processing data transferred from the control / decoding board 456 to the main control board 431 via a data transfer link. It is connected to the control board 431. The main control board 431 is connected to a connector on the exterior in order for the series output port to transfer decoded data, i.e. image data, to a remote terminal via a cable connection (not shown). The connector may be a conventional pin connector to which the connector of the other party is fixed. Alternatively, as shown in FIGS. 10 and 11, the connector is a conductive contact surface 460 (FIGS. 10 and 11) outside the exterior 410 and is the counterpart when the device is installed at the inspection base (not shown). It may be a conductive contact surface that is consistent with the contact surface of. Since the data collection system 400 is intended for mobile use, the host computer Wired connections with computers are not feasible in many situations. Therefore, the portable data acquisition system 400 is a spread spectrum microradio mounted on board 433 (FIGS. 11 and 13) that establishes a wireless link between the mainframe 431 and the remote host computer (not shown). It has. The external antenna 446 as shown in FIG. 10 or the internal antenna 447 as shown in FIG. 13 promotes wireless communication reception. The spread spectrum radio board 433 is composed of digital / analog circuits for transmitting and receiving data in a wireless network such as an IEEE 802.11-compliant direct spread spectrum network or a frequency hopping spread spectrum network. Power is supplied to the circuit of system 400 by power cell 448. Both the spectral diffusion radio and the data reader module draw significant current from the power cell 448. Therefore, the radio should not operate during the data form reading period. Further, the data type reading period should not be started during communication in order to limit the extraction of the peak current. Therefore, the radio circuit and the reader module output blocking signals to each other so that they do not draw power at the same time. A blocking signal from the radio to the reader module blocks the start of the reading period. The period is postponed until the signal stops. The blocking signal from the reader module to the radio blocks the radio from sending and receiving data packets. Therefore, the network transmission convention must provide complete control over when the radio in the portable data reader can send packets and receive data packets. One such network communication convention is the reverse polling convention described in US Pat. No. 3,276,680, which has been approved by Telesystems S / W Inc. The third,276, No. 680 is quoted in its entirety for reference in this book. Inversion polling convention In the case of a network, the radio of the portable device sends a data packet to the access point of the network at an arbitrary time point without fixing the carrier frequency. However, the access point can send the packet to the portable device only within the time window after receiving the packet from the portable device. The portable device sends packets on a regular basis so that the access point can frequently find opportunities to send data to the portable device. However, the packet does not contain important data. Spectral diffusion radios are effective in transmitting the decoded content of the data form, but due to the limited frequency bandwidth of the radio, it is not possible to transmit the entire uncompressed image. An image compression algorithm useful for reducing the size of digital image files is described in "64kps Video Code with 2D Wavelet Transformation" by AS Lewis and G. Knowles (IEEE Computer Society Publishing, order number 2202). It is a two-dimensional wavelet transformation of. For example, with the HARC Wavelet Conversion System released by the Houston Advance Research Center in Houston, Texas, up to 400: The captured image can be compressed before transmission with an image compression rate of 1. Since the portable data collection system 400 of the present invention is intended for use in a remote location, an operator working in a remote location of a facility issues a monitoring command while capturing and decrypting a data form. It may be necessary to request. Therefore, the data collection system 400 of the present invention is predominantly provided with a voice mail circuit 438 (FIG. 14) so that the operator can communicate in a language via a spread spectrum network. With reference to FIG. 14, a block diagram of the voice mail circuit 438 is presented. This circuit is realized in a microprocessor system (not shown), a voice mail processing board 437, or a main control board 431 (FIGS. 11 and 13). Returning to FIG. 14, the voice message is input via the voice input circuit 492, which will be discussed in detail after having a port for connecting to an internal microphone or an external microphone. The digitizer / compression module 494 creates a digital data file that represents the audio input. Before sending the message, the message control unit 498 prompts the operator to recognize the address. The prompt may be in the form of an audible signal sent to the operator via the voice output circuit 500 (discussed later) or in the form of a message on the display screen. The operator must recognize the address within the time window following the prompt. This is done via keyboard 422 or touch panel 444 (shown in FIGS. 10-13). Alternatively, the address is recognized by voice input. In this embodiment, the voice recognition circuit 502 converts the voice signal into a digital address. The message control unit 498 adds an address to the message, relays the message to the spread spectrum transmitter / receiver, and broadcasts the message to the receiver. Note that the voice mail system can require the operator to recognize the recipient before or after entering the message. The message control unit 498 receives a data file representing an incoming voice mail message and stores the message in the memory 496. Receive an incoming message and next First, the control unit 498 notifies the operator of the reception via the voice output circuit 500, the display screen, or the dedicated illuminator. At the operator's prompt to output a voice mail message, Control Unit 498 receives the data file from memory. The decompression module converts the data file into an analog signal. A voice output circuit with a speaker, a remote speaker, or a port for a headset outputs a message. The operator's prompt to output a message is output via the keyboard 422, the touch panel 444, or the voice input circuit 492. After outputting the message, the voice mail circuit 438 selectively stores the message or deletes the message for later playback. The message is forwarded or replied to as it is stored or erased. The voicemail circuit 438 prompts the operator to enter various permutations of these options. When the message is stored, the digital data file remains in memory 496. When transferred, the data file or copy is properly addressed and transmitted to the spread spectrum radio board 433. If the response option is selected, you will be notified of an address match in the response message. Then, the message control unit 498 causes the operator to input a response message at the prompt. The digital data file representing it is transmitted by the spectral diffusion radio board 433. Referring to FIG. 12, the speaker 450 and the microphone 452 are preferably positioned so that the portable data communication system 400 is held on the side surface of the operator's face like a telephone and can communicate with each other. In another embodiment of the portable data acquisition system 400 shown in FIGS. 12 and 13, a wireless headset 550 is used in place of the speaker 450 and microphone 452 mounted on the exterior 410. In the embodiment shown in FIG. 15, the speaker 517 and the microphone 519 are realized in the wireless headset 550. The headset is a headband 515 for holding the device on the operator's head. To be equipped. The speaker 517 is positioned near the operator's ear, and the microphone 519 is positioned near the operator's mouth. The micro radio module and power supply are installed in a storage box 521 attached to the headset 500. Similarly, the system exterior 410 houses a matched microradio module (not shown) that sends and receives audio signals to and from the headset. The micro radio module operates in a narrowband modulation scheme. In the narrowband modulation scheme, the frequency band is aligned with the zeros of the frequency spectrum of the spread spectrum radio. In addition to working with a wireless headset, the microradio can also act as a wireless peripheral port so that the operator can print data labels without having to physically connect the data acquisition system to the printer. it can. A printer or another peripheral with a similar micro wireless board is installed during the installation period when the data acquisition system is in operation. When the operator approaches the peripheral in the system, the handshake procedure is initiated and the wireless link is set. Then, the data is printed by the peripheral device. Since the data collection system 400 of the present invention is intended for portable use, it is desirable that the power supply 30 (FIGS. 11 and 13) be operated for a long period of time without requiring recharging. The power source 30 may be any rechargeable cell, but preferably the power source is composed of a plurality of flexible battery cells made of polymerized lithium. Each flexible sheet is approximately thick. It's 002 inches (2mils) and looks like a plastic sheet. To construct such a cell, LiMn20 4 is used as the cathode and carbon dioxide is used as the anode. This type of cell is available from Bellcore, Red Bank, NJ. The advantage of polymerized lithium cells is that the flexible sheet forming factor is that the cells are folded and placed in areas within the exterior that are unsuitable for conventional cylindrical cells. In FIG. 13, the polymerized sheet-like cell of the power source 30 is predominantly installed along the inner surface of the exterior. In this case, the polymerized cell also exerts a function of reducing unnecessary EMS. In addition to the advantages of forming factors and EMS, polymerized lithium cells are rechargeable and achieve approximately three times the energy concentration of nickel-cadmium cells. Moreover, it does not suffer from the crystallization of nickel-cadmium, which causes a degenerative memory effect. Although the present preferred embodiments of the present invention have been described, those skilled in the art can realize other modifications without departing from the present invention, and all modifications and modifications fall within the scope of the present invention. Will be recognized. According to legislation, the present invention has been described using a language that is somewhat specific to structural and methodological features. However, it is understood that the invention is configured in a suitable manner for carrying out the invention by the means disclosed herein and is not limited to the particular features illustrated and described. There will be. The present invention is therefore claimed in any form or modification within the appended claims that are appropriately construed on the basis of the doctrine of the equivalent. 4 is used as the cathode and carbon dioxide is used as the anode. This type of cell is available from Bellcore, Red Bank, NJ. The advantage of polymerized lithium cells is that the flexible sheet forming factor is that the cells are folded and placed in areas within the exterior that are unsuitable for conventional cylindrical cells. In FIG. 13, the polymerized sheet-like cell of the power source 30 is predominantly installed along the inner surface of the exterior. In this case, the polymerized cell also exerts a function of reducing unnecessary EMS. In addition to the advantages of forming factors and EMS, polymerized lithium cells are rechargeable and achieve approximately three times the energy concentration of nickel-cadmium cells. Moreover, it does not suffer from the crystallization of nickel-cadmium, which causes a degenerative memory effect. Although the present preferred embodiments of the present invention have been described, those skilled in the art can realize other modifications without departing from the present invention, and all modifications and modifications fall within the scope of the present invention. Will be recognized. According to legislation, the present invention has been described using a language that is somewhat specific to structural and methodological features. However, it is understood that the invention is configured in a suitable manner for carrying out the invention by the means disclosed herein and is not limited to the particular features illustrated and described. There will be. The present invention is therefore claimed in any form or modification within the appended claims that are appropriately construed on the basis of the doctrine of the equivalent. 4 is used as the cathode and carbon dioxide is used as the anode. This type of cell is available from Bellcore, Red Bank, NJ. The advantage of polymerized lithium cells is that the flexible sheet forming factor is that the cells are folded and placed in areas within the exterior that are unsuitable for conventional cylindrical cells. In FIG. 13, the polymerized sheet-like cell of the power source 30 is predominantly installed along the inner surface of the exterior. In this case, the polymerized cell also exerts a function of reducing unnecessary EMS. In addition to the advantages of forming factors and EMS, polymerized lithium cells are rechargeable and achieve approximately three times the energy concentration of nickel-cadmium cells. Moreover, it does not suffer from the crystallization of nickel-cadmium, which causes a degenerative memory effect. Although the present preferred embodiments of the present invention have been described, those skilled in the art can realize other modifications without departing from the present invention, and all modifications and modifications fall within the scope of the present invention. Will be recognized. According to legislation, the present invention has been described using a language that is somewhat specific to structural and methodological features. However, in the present invention, the means disclosed in this document is the present. It will be appreciated that it is configured in a suitable manner for carrying out the invention and is not limited to the particular features illustrated and described. The present invention is therefore claimed in any form or modification within the appended claims that are appropriately construed on the basis of the doctrine of the equivalent.