JP3500147B2 - Electronic still camera system, image data processing method, and image data recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an electronic still camera system, an image data processing method, and an image data recording device, which include an image pickup device, AD conversion means, frame memory, data compression means, and the like.

[0002]

[Prior art]

As a conventional electronic still camera, there is one that can record a frame image of about 20 frames on a 2-inch magnetic disk. When recording 20 or more images with this camera, replace the new magnetic disk and record. That is, the magnetic recording format is a floppy disk format, and the disks can be exchanged.

[0003]

[Problems to be Solved by the Invention]

Although the electronic still camera is inferior to the silver salt camera in terms of resolution, it is excellent in immediate effect of reproduction, transferability, editability, searchability and the like.

It is said that high-speed continuous shooting is also one of the excellent points of the electronic still camera, and the user's needs for this are high. However, at present, the recording speed of this magnetic disk is limited to 15 frames / sec. Moreover, since the recording capacity (number of sheets) is about 20, continuous shooting ends in about 1 second. As described above, in terms of recording speed and recording time, it is difficult to take a single golf swing in continuous shooting with the current electronic still camera. There is no doubt that the number of pixels will increase in the future in order to increase the resolution, but when the number of pixels for the HDTV system is reached, for example, the number of recorded images for continuous shooting and the recording speed will drop further considering the amount of data. It will be reduced to about / 5.

Therefore, an object of the present invention is to significantly increase the recordable number of continuous shots and the recording / reproducing speed of continuous shots in an electronic still camera system capable of single-frame shooting and continuous shooting. Provided are an electronic still camera system, an image data processing method, and an image data recording device capable of coping with a reproduction function such as reverse reproduction of each image and search reproduction for each frame, editability, and searchability. To do.

[0006]

[Means for Solving the Problems]

In order to solve the above problems and achieve the object, an electronic still camera system, an image data processing method, and an image data recording apparatus of the present invention are configured as follows.

(1) The electronic still camera system of the present invention is a DCT conversion and Huffman corresponding to intra-frame compression or continuous recording including DCT conversion and Huffman coding processing corresponding to one frame recording of a supplied image signal. Image data compression means for performing inter-frame compression including encoding processing, and recording means capable of image recording on an applied recording medium and capable of image recording by single-frame recording or continuous recording And reproducing from the recording medium to generate compressed image data which has been subjected to DCT conversion and Huffman coding processing corresponding to one frame recording from image data compressed corresponding to the continuous recording in the image data compression means. An electronic still camera including an output unit that outputs the restored predetermined image data, and is added to the electronic still camera. Is, the image data output by said output means, and characterized in that it comprises again, and an image data recording device adapted to record on the storage subjected to compression corresponding to the one frame recording.

(2) An image data processing method for an electronic still camera system according to the present invention is an electronic still camera system, wherein interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording is performed on a supplied image signal. Compressed image data is generated by performing the decoding, and the compressed image data is decoded, and the decoded image data is used to generate the intra-frame compressed image data that has been subjected to DCT conversion and Huffman coding processing corresponding to one frame recording. It is characterized by having done.

(3) The electronic still camera system of the present invention is a digital still camera system, wherein in the electronic still camera system, compression means for performing interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording of the supplied image signal,
Outputting means for outputting the compressed image data compressed by the compressing means, and generating in-frame compressed image data which has been subjected to DCT conversion and Huffman coding processing corresponding to one frame recording from the image data output by the outputting means. And a means for doing so.

(4) In the image data recording apparatus of the present invention, in the recording apparatus of the electronic still camera system, compressed image data subjected to interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording is input. When this is done, the DCT corresponding to single frame recording from this compressed image data
It is characterized by comprising means for generating and recording the intra-frame compressed image data which has been subjected to the conversion and Huffman coding processing.

[0011]

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram showing a part of the configuration of an electronic still camera system according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the remaining part of the configuration of the camera system.
The configuration of this embodiment will be described below with reference to FIGS. 1 and 2. A subject image incident on the photographing element 1 through the lens 50 is converted into a video signal by the photographing element 1. This video signal is amplified by the preamplifier 2 and then the A / D converter 3
Is converted into a digital signal and is temporarily stored in the frame memory 4. The frame memory 4 is for performing time conversion and data string conversion for various signal processing thereafter. The video signal is converted by the frame memory 4 and the video process circuit 5 into a sequential signal of Y, RY, BY. Further, in the data compression block 6 in the subsequent stage, in order to perform data compression described later, each of the sequential signals (Y, RY, BY) is output as image data for each block of 8 × 8 pixels. The image data compressed by the data compression unit 6 is recorded on the recording medium 8 via the recording unit 7. When the recording medium 8 is a magnetic disk, a magnetic tape or the like, the recording unit 7 is composed of an error correction coding circuit and a recording modulation circuit. When the recording medium 8 is a semiconductor memory such as a memory card, it is not necessary.

Next, the data compression circuit 6 will be described. The data compression circuit 6 is configured so that compression within a frame and compression between frames can be performed simultaneously. It is also possible to set only compression within a frame by switching. Data compression in the frame is high quality and high compression rate.
It is performed by the ADCT (Adaptive Discrete Cosine Transformer) method as shown in -283761. For inter-frame data compression, motion compensation inter-frame prediction is performed for each block using the previous frame, the prediction error is obtained by taking the difference from the current frame, and the prediction error signal is quantized. It is carried out by the method.

First, the operation of the data compression circuit 6 when shooting one frame will be described. The camera 24 has a changeover switch 36 for selecting one frame shooting or continuous shooting. When this is set to one frame shooting, the changeover switch 10 is switched to the terminal 11 side through the control unit 9, and the subtraction circuit 12 only allows the video signal to pass. At this time, the inverse quantization circuit (representative value setting circuit) 13, the inverse DCT circuit 14, the addition circuit 15, the frame memory 16, the frame memory control unit 17, and the motion vector detection unit 18 are not used. Therefore, the power supply is set to the OFF state through the power supply control unit 19.
8 by the frame memory 4 and the video process circuit 5
Sequential signals of Y, RY, and BY converted in block units of × 8 pixels are two-dimensional D by the DCT circuit 20 for each block.
Converted to CT coefficient (8 × 8 coefficient). Next, the quantization circuit 21
Thus, the two-dimensional DCT coefficient is divided by a quantization width (quantization matrix) previously assigned to each frequency component to perform linear quantization according to each frequency component. This quantization width usually increases as it approaches the high frequency component. This is because the high-frequency component has a low frequency of occurrence and a small amplitude, and therefore a slight drop in the visual characteristics does not significantly affect the image quality. By utilizing this, and performing the above quantization, the compression effect in the encoding circuit 22 in the subsequent stage can be significantly increased.
That is, in the encoding circuit 22, the quantized 8 × 8 system matrix is operated in a zigzag manner from the low frequency component in the upper left to the high frequency component in the lower right to increase the frequency of continuation of zero value components to 2 Performs dimensional Huffman coding. Therefore, by performing the above-described quantization, the high frequency component continues to have almost zero value, and the compression effect by the two-dimensional Huffman coding can be significantly improved. A detailed description of the ADCT method is given in Japanese Patent Application No. 01-283761.
Further, the two-dimensional Huffman coding is a variable length code, but it is desirable that the code amount of one screen is constant in consideration of retrieval, editing and the like. Using the two-dimensional Huffman code,
Further, the above application also describes a method of keeping the code amount per screen constant.

Next, the operation of the data compression circuit 6 when performing continuous shooting, that is, continuous shooting will be described. First, when the changeover switch 36 is set to continuous shooting and the shutter 26 is pressed, the power supply of each required circuit is activated through the power supply control unit 19. In particular, the subtraction circuit 12, the inverse quantization circuit 13, the inverse DCT circuit 14, the addition circuit 15, the frame memory 16, the frame memory control unit 17, and the motion vector detection unit 18 are Differently set to operating state. Then, after the autofocus operation, photometry, and the like are performed, continuous shooting is started. For the first image frame after continuous shooting is started, the changeover switch 10 is switched to the terminal 11 side, and the same compression (intra-frame compression by ADCT) as in the one frame shooting described above is performed and recorded. It is recorded on the medium 8. At the same time, the output of the quantization circuit 21 is the inverse quantization circuit 13 and the inverse DCT circuit 1
4, the original image is decoded and stored in the frame memory 16 as the first frame data. However, the frame data at this time is stored as a form including a quantization error by the quantization circuit 21. At the same time, this frame data is subjected to correlation calculation with the second frame signal (current frame signal 25) output from the video process circuit 5 in the motion vector detecting section 18, and each block of the second frame (current frame) is calculated. The reference motion vector is detected. Then, the data of 8 × 8 pixels of the first frame (previous frame) at the position corresponding to this motion vector is read from the frame memory 16 through the memory control unit 17. Then, the subtraction circuit 12 subtracts the difference from the image data 25 of the second frame (current frame). Then, this difference is compressed by the ADCT method described above. That is, the DCT circuit 20 allows the DCT in the frame
After the conversion is performed and a predetermined quantization is performed by the quantization circuit 21, the Huffman coding is performed by the coding circuit 22, and the Huffman coding is stored in the recording medium 8. At this time, the motion vector signal 28 is also coded by the coding circuit 22 and recorded together with the block data. Since the data amount of this difference has a high correlation between frames, when the motion-compensated inter-frame prediction is performed, the data amount becomes extremely small, and after the encoding circuit 22, compression of about 1/100 is possible. Now on the recording medium 2
When using an M BYTE memory card, the continuous shooting duration can be about 16 to 20 seconds. When the subtraction circuit 12 takes the difference between the image data of the first frame and the image data of the second frame, the changeover switch 10 is naturally changed over to the terminal 23 side. And the difference of this data is immediately calculated by the circuit 20,2.
It is decoded through 1, 13 and 14 and the adder circuit 15, and is stored in the frame memory 16 and the buffer memory in the motion vector detecting unit 18. Writing to and reading from frame memory 16 is 2
Since there is a time delay due to the processing of the circuits of 0, 21, 13, and 14, data at the same address will not be shared, and simultaneous access is possible if writing and reading are performed on a clock-by-clock basis. When the data are shared, a delay circuit having a delay amount corresponding to the data may be inserted after the adder circuit 15. The delay amount of the delay circuit is detected by detecting the motion vector from the time when the current frame signal 25 is input to the motion vector detecting unit 18, and correspondingly reading the data of the previous frame from the frame memory 16 through the memory control unit 17. Is set to the time until, and the processing of the subtraction circuit 12 can be performed in real time. For the compression of the third frame and thereafter, the above-described operation is repeated to perform the compression. Then, in the image data, address information (for searching and editing), ID information (date, etc.), and a continuous shooting identification signal 29 for identifying one frame shooting and continuous shooting are respectively coded with the control circuit 9. It is added through the conversion circuit 22. By the way, as shown in the figure, in the data compression circuit 6, a local decoder 27 is purposely provided in order to detect a prediction error from the previous frame to form a feedback configuration, and the DCT circuit 20 and the quantum are included in this feedback loop. The conversion circuit 21 is inserted. The reason is that the prediction error is quantized while considering the integral value of the quantization noise caused by the quantization, so that noise is prevented from being accumulated at the time of decoding.

Next, the operation of reproducing an image will be briefly described. First, when playing back one frame, the selector switch 10
Set on the 11 side. Then, the compressed image data is read from the recording medium 8 according to the set address. When the recording medium 8 is a magnetic disk or a magnetic tape, the recording unit 7 demodulates the recording code and corrects the error. Then, it is input to the encoding circuit 22 and the two-dimensional Huffman is decoded. Then, the inverse quantization circuit 13 and the inverse DCT
The image data is restored through the circuit 14. The restored image data is converted by the serial-parallel converter 30 into Y, RY, BY parallel signals, and converted by the NTSC circuit 31 into NTSC signals. Then, it is converted into an analog signal by the D / A converter 32 and displayed on the TV monitor 33.

Next, reproduction of continuous shooting will be described. In this case, the change-over switch 10 is set to the terminal 23 side after the first image is restored by the same process as one frame reproduction and stored in the frame memory 16. This is because the encoding circuit 22 determines the continuous shooting identification signal 29 added to the beginning of the compressed data, and the control unit 9
Controlled through. And after that, the local decoder for continuous shooting
Exactly the same operation as 27, the continuous shot image is reproduced. By the way, in the continuous shooting method of the present invention, in addition to intra-frame compression (ADCT), inter-frame compression is performed by the prior value prediction method. For this reason, even if normal reproduction is possible, it becomes difficult to perform trick reproduction such as reverse reproduction and search and reproduction for each frame. Therefore, when the data is transferred to an electronic album device 60 such as a magnetic disk, an optical disk, or a digital VTR, intra-frame compression (ADCT) is performed again in the circuit 34 and then recorded in the mass storage 35. This allows trick play, search, and edit.

[0017]

【The invention's effect】

According to the present invention, in an electronic still camera system capable of single-frame shooting and continuous shooting, a large amount of data compression is possible, so that the recordable number of continuous shots and the recording / playback speed of continuous shots are greatly increased. Means and method for generating image data compressed by the intra-frame compression method corresponding to one frame recording from image data compressed by the inter-frame compression method corresponding to continuous recording in the image data compression means, and apparatus for recording the same Therefore, for example, an electronic still camera system and image data that can be used so as not to impair reproduction functions such as reverse reproduction and search reproduction for each frame of continuously recorded images, editability, and searchability. A processing method and an image data recording device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a partial configuration of an electronic still camera system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of another part of the electronic still camera system according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Shooting terminal, 3 ... A / D converter, 4 ... Frame memory, 6 ... Data compression section, 9 ... Control section, 36
...... One frame / continuous shooting switch.

Continuation of the front page (56) References JP-A-3-250987 (JP, A) JP-A-1-177281 (JP, A) JP-A-62-82886 (JP, A) JP-A-64-81583 (JP , A) JP-A-63-122392 (JP, A) JP-A-62-269581 (JP, A) JP-A-1-274588 (JP, A) JP-A-3-254579 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1 / 41,5 / 76-5 / 956,7 / 24

Claims (4)

(57) [Claims] 1. A supplied image signal is subjected to intraframe compression including DCT conversion and Huffman coding processing corresponding to one frame recording, or interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording. Image data compression means, recording means capable of recording images on an applied recording medium, and image recording by single-frame recording or continuous recording; and the continuous recording means in the image data compression means. DC for single frame recording from compressed image data for recording
An electronic still camera including an output unit that outputs predetermined image data reproduced and restored from the recording medium to generate compressed image data that has been subjected to T conversion and Huffman coding processing, and is added to the electronic still camera. And an image data recording device configured to record the image data output by the output means into a storage by performing compression corresponding to the one-frame recording again, and an electronic still device. Camera system. 2. An electronic still camera system, wherein compressed image data is generated by performing interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording on a supplied image signal, and the compressed image data is converted into the compressed image data. An image data processing method for an electronic still camera system, which is characterized in that the decoded image data is subjected to DCT conversion corresponding to one frame recording and Huffman-encoded in-frame compressed image data is generated from the decoded image data. . 3. In an electronic still camera system, compression means for performing interframe compression including DCT conversion and Huffman coding processing corresponding to continuous recording of a supplied image signal, and compressed image data compressed by the compression means. And output means for outputting the image data output by the output means, and means for generating intra-frame compressed image data that has been subjected to DCT conversion and Huffman coding processing corresponding to one frame recording from the image data output by the output means. Electronic still camera system. 4. A recording device of an electronic still camera system, wherein when compressed image data subjected to inter-frame compression including DCT conversion and Huffman coding processing corresponding to continuous recording is input, one frame from this compressed image data is input. Corresponding to the record
An image data recording apparatus comprising means for generating and recording intra-frame compressed image data that has been subjected to DCT conversion and Huffman encoding processing.