Imaging device

The present invention relates to a high-speed imaging device capable of slow motion reproduction.

In recent years, the performance of video cameras has improved, and in particular, with the progress of digital technology, slow motion shooting that shoots at a higher speed than usual has become possible. Especially in sports broadcasting, beautiful slow motion playback is a major feature in program production.

When performing high-speed photography, it is necessary to obtain a signal having a frequency band equal to that of a conventional standard video signal. That is, in order to obtain 1/3 slow playback, when shooting at 3x speed, a data rate 3 times the normal data rate is required as the output of the camera. Data output from the camera at 3x speed, which is different from the normal video signal format, is required, and a transmission device dedicated to high-speed shooting is also required for the signal transmission.

As one method for solving the problem, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 2000-188703, and the configuration thereof is shown in FIG. In FIG. 5, 101 is a video camera, 102 is a CCU (camera control unit), 110 is an imaging device, 111 is an A / D conversion circuit, 112 is a memory, 113 is a process LSI, 120 is a process LSI, 121 is a memory, 122. Is a switching circuit and 123 is a transmission line.

The operation of the conventional imaging device configured as described above will be described below by taking 3x speed imaging as an example.

First, in the video camera 101, the video signal SO taken at a high speed three times the standard by the imaging device 110 is converted into a digital video signal by the A / D conversion circuit 111, and the standard speed is converted by the memory 112. The three video signals SO1 to SO3 are separated, and these three standard video signals SO1 to SO3 are converted into standard video signals S1 to S3 of a predetermined transmission format by the process LSI 113 and used by the camera via the wideband transmission line 123. It is transmitted to the control unit 102.

Here, a blank field is included when the high-speed shot video SO having a speed of 3 times or less is separated into a plurality of standard video signals SO1 to SO3. The blank field signal Sbf indicates which field of the plurality of standard video signals SO1 to SO3 contains the blank field. The blank field signal Sbf is also transmitted to the camera control unit 102 via the transmission line 123.

In the camera control unit 102, the three standard video signals SO1 to SO3 transmitted via the transmission line 123 are converted into three standard video signals SU1 to SU3 that can be internally processed by the process LSI 120, and 3 by the switching circuit 122. The standard speed video signals of books are arranged for each unit period and output to various video devices as multiple SDI outputs SI1 to SI3.

Here, the memory 121 discriminates the blank field from the blank field signal Sbf, accumulates only valid images from the three standard video signals SU1 to SU3, and outputs the slow reproduction signal SL from the memory 121.

In the video camera 101, after converting the 3x high-speed video SO into three standard video signals SO1 to SO3 using the memory 121, the three standard video signals SO1 to SO3 are input to the process LSI 113. There is. Here, the process LSI 113 has a function of processing a video signal peculiar to a camera and a transmission process function of converting the video signal into a transmission format. Although the process LSI 113 is shown as a single process in FIG. 5, the video signal processing and the transmission processing may be configured by separate ICs, and the three standard video signals SO1 to SO3 may be used. On the other hand, it may be composed of three ICs for video signal processing, and in this case, the IC for the process of the conventional standard camera can be used as it is to configure the circuit.

The transmission format conversion process IC uses three standard digital video signals for internal processing of the camera as standard 4: 2: 2 luminance signals and color difference signals Y, CB, CR, transmission frequency 27 MHz, and 10 bits. Converts to a format equivalent to the D1 format signal composed of parallel signals. Then, in order to transmit the signal line, the power supply line, and the control line via the transmission line 123 such as an optical fiber or TRIAX, time division multiplexing processing of three video signals is performed. Alternatively, not limited to this, it is also possible to transmit using three BNC cables as equivalent to three 270 MHz serial SDI signals.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2000-188703 (pages 3-5)</text></patcit>

<p> However, in the above technology, in order to transmit triple signal data corresponding to triple speed from the camera head in high-speed shooting, time division multiplexing of three video signals is performed in transmission with the camera control unit. It is necessary to process or prepare three BNC cables. Further, in order to perform slow playback, there is a problem that it is necessary to connect, for example, three VTRs to the camera control unit and perform synchronous operation.</p><p> The present invention solves the above-mentioned conventional problems, and an object of the present invention is to obtain a slow-motion reproduced image without requiring a special transmission device or a special external recording device in a high-speed imaging device.</p>

<p> The invention according to claim 1 of the present invention includes an imaging means for photographing a subject in a first cycle, a compression means for compressing a video signal captured by the imaging means, and a video signal compressed by the compression means. A storage means for storing the data and a decompression means for reading, decompressing, and outputting the video signal data stored in the storage means in the second cycle, and the second cycle is longer than the first cycle. It has the function of obtaining a slow reproduction signal from an image pickup device without the need for a special external recording device.</p><p> The invention according to claim 2 of the present invention includes a conversion means for converting a video signal of the first cycle captured by the imaging means into a video signal of the second cycle, and signals of the stretching means and the conversion means. It is characterized by being provided with a selection means for switching between, and has an effect of being able to record a high-speed imaging signal for slow reproduction in a memory and at the same time output a normal-speed video signal.</p><p> The invention according to claim 3 of the present invention includes a conversion means for converting a video signal of the first cycle imaged by the imaging means into a video signal of the second cycle, and the output signal of the stretching means and the said. It is characterized by outputting the output signal of the conversion means together, and has the function of being able to always output a normal speed video signal while having the feature of being capable of slow reproduction.</p><p> The invention according to claim 4 of the present invention is characterized in that the conversion means outputs a part of the video signal as the second cycle from the video signal of the first cycle imaged by the imaging means. It has an effect that a normal speed video signal can be obtained by a simple method of field thinning.</p><p> In the invention according to claim 5 of the present invention, the conversion means performs an addition operation on a plurality of video signals of the first cycle imaged by the imaging means and outputs them as video signals of the second cycle. This is a feature of the above, and has the effect of being able to obtain a signal with less noise as a normal-speed video signal during high-speed shooting.</p><p> The invention according to claim 6 of the present invention is characterized in that the storage means is a semiconductor memory, and has an effect of facilitating variable speed data recording such as high-speed imaging.</p><p> The invention according to claim 7 of the present invention is characterized in that the storage means is a removable non-volatile memory, and by connecting a memory storing a high-speed imaging signal to another playback device. It has the effect of being able to easily perform slow playback without the need for signal transmission.</p><p> The invention according to claim 8 of the present invention is characterized in that the first cycle and the second cycle have an integer ratio, and has an effect of simplifying memory control.</p>

<p> As described above, according to the present invention, it is possible to obtain an excellent effect that a slow motion reproduced image can be obtained without requiring a special transmission device or a special external recording device in the high-speed imaging device.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of an image pickup apparatus according to the first embodiment of the present invention.

In FIG. 1, 1 is an imaging unit, 2 is an A / D converter, 3 is a camera signal processing circuit, 4 is a speed conversion circuit, 5 is a compression circuit, 6 is a memory, 7 is an expansion circuit, 8 is a control circuit, and 9 Is the selector and 10 is the output terminal.

Regarding the operation of the imaging device according to the first embodiment configured as described above, for example, when high-speed imaging with a slow motion image speed ratio of 1/3, that is, 3x speed is performed, FIGS. 1 and 2 are shown below as appropriate. Refer to and explain.

In FIG. 1, the image pickup unit 1, the A / D converter 2, and the camera signal processing circuit 3 are components of a normal camera, and their operations are basically the same. That is, the image pickup unit 1 converts an optical image signal into an electric signal and outputs the signal, and includes, for example, a CCD (Charge Coupled Device) type image pickup device, a drive circuit thereof, and an analog signal processing circuit. The A / D converter 2 converts the analog video signal output from the imaging unit 1 into a digital video signal and inputs it to the camera signal processing circuit 3. In the camera signal processing circuit 3, signal processing necessary for a normal camera such as offset adjustment, gain adjustment, gamma correction, and contour correction is performed, and the output signal becomes a standard form video signal that can be recorded and displayed.

Here, since high-speed imaging at 3x speed is performed, it is necessary to generate a video signal of 180 fields in contrast to a normal video signal of 60 fields per second. Therefore, the image pickup unit 1 extracts the signal charge from the image sensor at three times the normal speed, and as shown in FIG. 2, 1A, 1B, 1C, every 1/180 second, which is 1/3 of the normal time. Video signals are output in the order of 2A, 2B, and so on. For this image pickup signal, the A / D converter 2 and the camera signal processing circuit 3 also operate at three times the normal speed.

The 3x speed video signal, which is the output of the camera signal processing circuit 3, is data-compressed in the compression circuit 5. This reduces the amount of data by processing such as blocking, DCT (discrete cosine transform), and quantization. This compressed video data is recorded in the memory 6, and the recording operation is controlled by the control circuit 8 and recorded at 3 times the normal speed. That is, as shown in FIG. 2, video data for one field is recorded every 1/180 second. The memory 6 may be a non-volatile memory such as a flash memory or a volatile memory such as SDRAM.

Next, the operation during slow playback will be described below. During playback, the control circuit 8 reads and controls the memory 6 and outputs data at a rate of 60 fields per second, which is the same as a normal video signal. The output data is subjected to the reverse processing of data compression such as IDCT (inverse discrete cosine transform) in the decompression circuit 7, and is returned to the form of a video signal. That is, as shown in Fig. 2, the video signal is output in the same 1/60 second interval as usual, such as 1A, 1B, 1C, 2A, 2B, so the time axis is set to 3 compared to the time of shooting. A double-magnified video signal can be obtained.

At the time of high-speed imaging at 3x speed, the 3x speed video signal output from the camera signal processing circuit 3 is input to the speed conversion circuit 4 at the same time as recording in the memory 6 as described above, and is a normal speed video signal. Is converted to. As a simple method for the conversion, as shown in FIG. 3, a video signal of 60 fields is generated by extracting the video signal from the video signal of 180 fields at a ratio of 1 field from 3 fields.

Then, the selector 9 selects the video signal to be output to the output terminal 10, and selects the signal on the a side at the time of high-speed imaging and the signal on the b side at the time of slow reproduction. That is, at the time of high-speed imaging, the video signal at 3x speed is recorded in the memory 6, and at the same time, the video signal converted to normal speed can be output and used in the same way as a normal camera. Further, at the time of reproduction, a slow reproduction signal can be obtained by reproducing the video signal recorded in the memory 6 at a speed of 1/3 as compared with that at the time of recording.

Further, FIG. 4 shows a block diagram showing another configuration. The configuration of the image pickup apparatus shown in FIG. 4 is almost the same as the configuration shown in FIG. 1, except that the selector 9 is omitted and the output terminal 11 is added. Other components and their operation are the same as in Fig. 1.

The imaging device having the configuration shown in FIG. 4 is characterized in that a normal speed video signal is always output from the output terminal 10 and a slow playback video signal is output from the output terminal 11. Therefore, by using the video signal of the output terminal 10, it is possible to always use it as a normal imaging device. When a slow reproduction signal is required, the signal of the output terminal 11 may be used. That is, by using the configuration shown in FIG. 4, it is possible to cope with a case where both a normal speed video signal and a slow playback signal are required.

As the speed conversion circuit 4, a simple method of thinning out fields has been described, but since the accumulation time in the image sensor is shorter than that of a normal video signal, the S / N becomes worse. Therefore, as the speed conversion circuit 4, for example, a video signal having a good S / N can be obtained by configuring the addition calculation from a plurality of fields.

Further, by using a semiconductor memory as the memory 6, it is possible to facilitate data recording at a signal data rate different from that in a normal time such as during high-speed imaging.

As in the present embodiment, control is easy when the field rate is an integral multiple of the normal imaging during high-speed imaging, but the field rate is not limited to an integral multiple.

Further, the image pickup device of the image pickup unit is not limited to the CCD, and the same effect can be realized by, for example, a CMOS type image pickup device that outputs a digital signal.

The image pickup apparatus according to the present invention is useful as a high-speed image pickup apparatus capable of realizing beautiful slow motion reproduction.

<figref num="1">Block diagram showing the configuration of the image pickup apparatus according to the first embodiment of the present invention.</figref><figref num="2">The figure which provides the description of the image pickup apparatus in Embodiment 1 of this invention.</figref><figref num="3">The figure which provides the description of the image pickup apparatus in Embodiment 1 of this invention.</figref><figref num="4">A block diagram showing a configuration of an image pickup apparatus according to another embodiment of the present invention.</figref><figref num="5">Block diagram showing the configuration of a conventional imaging device</figref>

Code description

1 Imaging unit 2 A / D converter 3 Camera signal processing circuit 4 Speed conversion circuit 5 Compression circuit 5 Memory 7 Decompression circuit 8 Control circuit 9 Selector 10 Output terminal 11 Output terminal