JP3645254B2 - Image data recording system and image data recording method - Google Patents

Description

  The present invention relates to an image data recording system and an image data recording method suitable for image data subjected to intra-frame compression or inter-frame compression.

Some conventional electronic still cameras can record about 20 frame images on a 2-inch magnetic disk. When recording 20 or more images with this camera, the new magnetic disk is replaced and recorded. That is, the magnetic recording format is a floppy disk format, and the disk can be exchanged (see Patent Document 1).
JP 63-122392 A

  Although an electronic still camera is inferior to a silver salt camera in terms of resolution, it is superior in terms of immediacy playback, electrical transmission, editing, searchability, and the like. The fact that high-speed continuous shooting is possible is said to be one of the excellent points of an electronic still camera, and the user needs for this are high. However, at present, the recording speed of this magnetic disk is limited to 15 frames / second. Moreover, since the recording capacity (number of sheets) is about 20, continuous shooting is completed in about 1 second. Thus, from the viewpoint of recording speed and recording time, it is difficult to take a single golf swing for continuous shooting with the current electronic still camera. In addition, it seems that the number of pixels will increase in the future in order to increase the resolution. For example, when the number of pixels of the HDTV system is reached, considering the amount of data, the number of continuous shots and the recording speed are further increased. It decreases and decreases to about 1/5.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image data recording system and an image data recording method which can cope with a continuously recorded image so as not to impair a reproduction function such as reproduction for each frame.

  In order to achieve the above object, the image data recording system and the image data recording method of the present invention have the following characteristic structures. In addition, about the characteristic structure of this invention other than the following, it clarifies in embodiment.

The image data recording system of the present invention includes one frame recording for generating image data subjected to intra-frame compression, continuous recording for generating image data subjected to inter-frame compression and image data subjected to intra-frame compression for at least one frame. A first image data compression means for performing intra-frame compression or inter-frame compression on the supplied image signal, and image data compressed by the first image data compression means Is recorded on a first recording medium in a state where it can be discriminated whether the image data is generated by the one-frame recording or the image data generated by the continuous recording, and the first recording means upon decoding the image data recorded on a recording medium, when the image data to be decoded is image data generated by the one frame recorded Performs frame in decoding, a decoding means for the decoding and inter-frame decoded frame when the image data of the decoding target is image data generated by the continuous recording, the intraframe decoder and the frame by the decoding means A second image data compression unit that performs intra-frame compression again on the inter-decoded image data, and a second image data that is compressed by the second image data compression unit and that is recorded on a second recording medium. And a recording means.

The image data recording system of the present invention generates one frame recording for generating image data subjected to intra-frame compression, image data subjected to inter-frame compression, and image data subjected to intra-frame compression for at least one frame. Image data compression means capable of performing continuous recording and performing intra-frame compression or inter-frame compression on the supplied image signal, and image data compressed by the image data compression means First recording means for recording on the first recording medium in a state where it can be identified whether the image data is generated by recording or the image data generated by continuous recording; and frame if upon decoding the recorded image data, image data to be decoded is image data generated by the one frame recorded Performs inner decoding, a decoding means for the decoding and inter-frame decoded frame when the image data of the decoding target is image data generated by the continuous recording, between the intraframe decoder and the frame by the decoding means A second recording unit for recording the image data generated by performing the intra-frame compression again on the decoded image data on a second recording medium.

The image data recording system of the present invention, there can correspond to a continuous recording of generating image data of at least one frame of intra-frame compression is been made with the image data is between frame over beam compression is performed, the supplied image signals The image data compression means adapted to perform intra-frame compression or inter-frame compression, and the image data compressed by the image data compression means can be identified as image data generated by the continuous recording When decoding the first recording means for recording on the first recording medium and the image data recorded on the first recording medium, the image data to be decoded is the image data generated by the continuous recording. In this case, decoding means for performing intra-frame decoding and inter-frame decoding, and the intra-frame decoding and inter-frame decoding by the decoding means. For image data, again, characterized by comprising a second recording means for recording the image data generated by performing intra-frame compression to the second recording medium.
The image data recording system of the present invention is compatible with continuous recording for generating image data subjected to inter-frame compression and image data subjected to at least one frame compression within a frame. Image data compression means adapted to perform internal compression or inter-frame compression, and image data compressed by the image data compression means in a state where the image data can be identified as image data generated by the continuous recording. A first recording means for recording on one recording medium, an output means for outputting image data recorded on the first recording medium, and an intra-frame compression for the image data outputted from the output means again. And a second recording unit for recording the image data generated by the recording on a second recording medium.

The image data recording method of the present invention generates compressed image data by performing inter-frame compression corresponding to continuous recording for a supplied image signal, and determines whether the compressed image data is continuous recording. Compressed image in which identifiable information is added and the compressed image data is subjected to inter-frame compression corresponding to continuous recording based on information that can be identified as to whether or not the continuous recording is added to the compressed image data When the data is data, the compressed image data is decoded, intra-frame compression processing is performed on the decoded compressed image data to generate intra-frame compressed image data, and the intra-frame compressed image data is recorded. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the image data recording system and the image data recording method which can respond | correspond so that reproduction | regeneration functions, such as reproduction | regeneration for every flame | frame, may not be impaired about the continuously recorded image can be provided.

(One embodiment)
FIG. 1 is a block diagram showing a part of the configuration of an electronic still camera using an image data recording 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 electronic still camera. . The configuration of this embodiment will be described below with reference to FIGS. A subject image incident on the image sensor 1 through the lens 50 is converted into a video signal by the image sensor 1. The video signal is amplified by the preamplifier 2, converted to a digital signal by the A / D converter 3, and temporarily stored in the frame memory 4. The frame memory 4 is for performing time conversion, data string conversion, and the like for subsequent various signal processing. The video signal is converted into sequential signals of Y, RY, and BY by the frame memory 4 and the video process circuit 5. Further, in order to perform data compression, which will be described later, in the subsequent data compression section 6, the sequential signals (Y, RY, BY) are 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 through the recording unit 7. When the recording medium 8 is a magnetic disk, a magnetic tape, or the like, the recording unit 7 includes an error correction encoding circuit and a recording modulation circuit. This is not particularly necessary when the recording medium 8 is a semiconductor memory such as a memory card.

  Next, the data compression circuit 6 will be described. This 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 within a frame is performed by an ADCT (Adaptive Discrete Cosine Transformer) system as shown in Japanese Patent Application No. 01-283761, which has high image quality and a high compression rate. For inter-frame data compression, motion compensation inter-frame prediction is performed for each block using the previous frame, and a prediction error is obtained by taking the difference from the current frame, and this value prediction is performed by quantizing the prediction error signal. Done in a manner.

  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 single frame shooting, the changeover switch 10 is switched to the terminal 11 side through the control unit 9, and the subtraction circuit 12 only passes the video signal. At this time, the inverse quantization circuit (representative value setting circuit) 13, the inverse DCT circuit 14, the adder circuit 15, the frame memory 16, the frame memory control unit 17, and the motion vector detection unit 18 are not used. For this reason, the power supply is set to the OFF state through the power supply control unit 19. The Y, RY, BY sequential signals converted into 8 × 8 pixel blocks by the frame memory 4 and the video process circuit 5 are converted into two-dimensional DCT coefficients (8 by the DCT circuit 20 for each block. X8 coefficient). Next, the quantization circuit 21 divides this two-dimensional DCT coefficient by a quantization width (quantization matrix) assigned in advance for each frequency component, thereby performing linear quantization corresponding to each frequency component. This quantization width is usually increased as it approaches the high frequency component. This is because high frequency components have a low frequency of occurrence and a small amplitude, so that even if some omissions occur due to visual characteristics, the image quality is hardly affected. By using this and performing the above quantization, the compression effect in the subsequent encoding circuit 22 can be significantly increased. In other words, the encoding circuit 22 zigzags the quantized 8 × 8 system matrix from the upper left low frequency component to the lower right high frequency component to increase the frequency of the zero value component to increase 2 Perform dimensional Huffman coding. For this reason, by performing the quantization as described above, the high-frequency component is almost zero, and the compression effect by the two-dimensional Huffman coding can be greatly increased. The above detailed description of the ADCT system is described in Japanese Patent Application No. 01-283761. 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 search, editing and the like. A method of using a two-dimensional Huffman code and making the code amount per screen constant is also described in the above application.

  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 of each necessary circuit enters an operating state through the power 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 different from each other when shooting one frame. It is set to the operating state differently. Then, after autofocus operation, photometry, etc. are performed, continuous shooting is started. For the first image frame after the 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 that for the one-frame shooting described above is performed, and recording is performed. Recorded on the medium 8. At the same time, the output of the quantization circuit 21 is decoded into the original image by the inverse quantization circuit 13 and the inverse DCT circuit 14 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 a correlation operation with the second frame signal (current frame signal 25) output from the video process circuit 5 in the motion vector detection unit 18, and each block of the second frame (current frame) is calculated. A reference motion vector is detected. Then, data for 8 × 8 pixels of the first frame (previous frame) at the position corresponding to the motion vector is read from the frame memory 16 through the memory control unit 17. Then, the difference from the image data 25 of the second frame (current frame) is obtained by the subtraction circuit 12. The difference is compressed by the above-described ADCT method. That is, the DCT circuit 20 performs DCT conversion within the frame, the quantization circuit 21 performs predetermined quantization, the encoding circuit 22 performs Huffman encoding, and the recording medium 8 stores the result. . At this time, the motion vector signal 28 is also encoded by the encoding circuit 22 and recorded together with the block data. Since the difference data amount has a high correlation between frames, if the motion compensation inter-frame prediction is performed, the amount of data becomes very small, and after the encoding circuit 22, compression of about 1/100 is possible. Now, when a 2M BYTE memory card is used as a recording medium, the continuous shooting duration can be about 16 to 20 seconds. When the difference between the image data of the first frame and the second frame is taken by the subtraction circuit 12, the changeover switch 10 is naturally switched to the terminal 23 side. This data difference is immediately decoded through the circuits 20, 21, 13, 14 and the adder circuit 15 and stored in the frame memory 16 and the buffer memory in the motion vector detection unit 18. Since writing to and reading from the frame memory 16 has a time delay due to the processing of the circuits 20, 21, 13, and 14, data at the same address will not be shared, and writing and reading can be performed in a time-sharing manner for each clock. Can be accessed simultaneously. When data is shared, a delay circuit having an appropriate delay amount may be inserted after the adder circuit 15. The delay amount of the delay circuit is such that the motion vector is detected from the time when the current frame signal 25 is input to the motion vector detecting unit 18 and the data of the previous frame is read from the frame memory 16 through the memory control unit 17 correspondingly. The subtraction circuit 12 can be processed in real time. The compression after the third frame is also performed by repeating the above-described operation. The image data includes address information (for searching and editing), ID information (date, etc.), a continuous shooting identification signal 29 for identifying single frame shooting and continuous shooting, and a control circuit 9. Added through the circuit 22. Incidentally, as shown in the figure, in the data compression circuit 6, a local decoder 27 is purposely provided 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. A circuit 21 is inserted. The reason is that the prediction error is quantized while taking into account the integrated value of the quantization noise caused by the quantization, so that the accumulation of noise during decoding is avoided.

  Next, an operation for reproducing an image will be briefly described. First, when performing one-frame playback, the changeover switch 10 is set to the terminal 11 side. Then, the compressed image data is read from the recording medium 8 in accordance with 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 two-dimensional Huffman is decoded. Then, the image data is restored through the inverse quantization circuit 13 and the inverse DCT circuit 14. The restored image data is converted into a parallel signal of Y, RY, BY by the serial / parallel converter 30 and converted into an NTSC signal by the NTSC circuit 31. Then, it is converted into an analog signal by the D / A converter 32 and displayed on the TV monitor 33.

  Next, continuous shooting reproduction will be described. In this case, the changeover switch 10 is set to the terminal 23 side after the first image is restored by the same process as the one-frame reproduction and stored in the frame memory 16. This is controlled by the control section 9 after the continuous shooting identification signal 29 added to the head of the compressed data is determined by the encoding circuit 22. After that, the continuous shot image is reproduced by the same operation as that of the continuous decoding local decoder 27. By the way, in the continuous shooting system of the present invention, in addition to intra-frame compression (ADCT), inter-frame compression is performed by a previous value prediction system. For this reason, even if normal playback is possible, trick playback such as reverse playback and search playback for each frame become difficult. Therefore, when changing to an electronic album device 60 such as a magnetic disk, an optical disk, or a digital VTR, the compression (ADCT) in the frame is performed again by the circuit 34 and then recorded in the mass storage 35. In this way, trick playback, searching and editing are possible.

  According to this image data recording system and image data recording method, since it is suitable for the reproduction processing of image data subjected to inter-frame compression, for example, recording of inter-frame compressed image data continuously recorded by an electronic still camera It is very suitable for.

1 is a block diagram showing a part of a configuration of an electronic still camera using an image data recording system according to an embodiment of the present invention. The block diagram which shows the remaining part of the structure of the electronic still camera using the image data recording system which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Imaging device, 3 ... A / D converter, 4 ... Frame memory, 6 ... Data compression part, 9 ... Control part, 36 ... Single frame / continuous shooting changeover switch .

Claims (5)

One frame recording for generating image data subjected to intra-frame compression, and continuous recording for generating image data subjected to inter-frame compression and image data subjected to intra-frame compression for at least one frame can be supplied. First image data compression means adapted to perform intra-frame compression or inter-frame compression on the image signal obtained,
The first recording in a state where it is possible to identify whether the image data compressed by the first image data compression means is the image data generated by the single frame recording or the image data generated by the continuous recording. First recording means for recording on a medium;
When decoding the image data recorded on the first recording medium, if the image data to be decoded is image data generated by the one-frame recording, intra-frame decoding is performed, and the image data to be decoded Decoding means for performing intra-frame decoding and inter-frame decoding when the image data is generated by the continuous recording ,
Second image data compression means for performing intra-frame compression again on the image data decoded by the decoding means within the frame and between frames;
Second recording means for recording the image data compressed by the second image data compression means on a second recording medium;
An image data recording system comprising: One frame recording for generating image data subjected to intra-frame compression, and continuous recording for generating image data subjected to inter-frame compression and image data subjected to intra-frame compression for at least one frame can be supplied. Image data compression means adapted to perform intra-frame compression or inter-frame compression on the image signal obtained,
The image data compressed by the image data compression means is recorded on the first recording medium in a state where it can be identified whether the image data is generated by the single frame recording or the image data generated by the continuous recording. First recording means for
When decoding the image data recorded on the first recording medium, if the image data to be decoded is image data generated by the one-frame recording, intra-frame decoding is performed, and the image data to be decoded Decoding means for performing intra-frame decoding and inter-frame decoding when the image data is generated by the continuous recording ,
Second recording means for recording the image data generated by performing intra-frame compression again on the second recording medium with respect to the image data decoded by the decoding means and the inter-frame decoding; and
An image data recording system comprising: A possible corresponding to the continuous recording of the inter frame over uncompressed generates image data by the image data with at least intra-frame compression of one frame is made has been made, so that intra-frame compression or inter-frame compression for the supplied image signal Image data compression means made to
First recording means for recording the image data compressed by the image data compression means on a first recording medium in a state where the image data can be identified as image data generated by the continuous recording ;
Decoding means for performing intra-frame decoding and inter-frame decoding when the image data to be decoded is image data generated by the continuous recording when decoding the image data recorded on the first recording medium ;
Second recording means for recording the image data generated by performing intra-frame compression again on the second recording medium with respect to the image data decoded by the decoding means and the inter-frame decoding; and
An image data recording system comprising: It is compatible with continuous recording for generating image data subjected to inter-frame compression and image data subjected to at least one frame of intra-frame compression, and is adapted to perform intra-frame compression or inter-frame compression on the supplied image signal. Image data compression means,
First recording means for recording the image data compressed by the image data compression means on a first recording medium in a state where the image data can be identified as image data generated by the continuous recording;
Output means for outputting image data recorded on the first recording medium;
A second recording unit that records the image data generated by performing intra-frame compression again on the second recording medium for the image data output from the output unit;
An image data recording system comprising: For the supplied image signal, compressed image data is generated by performing inter-frame compression corresponding to continuous recording,
Adds information that can be identified whether or not continuous recording to the compressed image data,
When the compressed image data is compressed image data that has been subjected to inter-frame compression corresponding to continuous recording, based on information that can be identified whether the continuous recording is added to the compressed image data. Decrypt the data,
Intra-frame compression processing is performed on the decoded compressed image data to generate intra-frame compressed image data,
An image data recording method for recording the in-frame compressed image data.

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