JPH03280679A - Recorder - Google Patents

Abstract

PURPOSE:To improve the consecutive shot function (consecutive shot speed) by setting the compressibility of compression processing applied to a picture data variably in response to a supply timing of a unit block corresponding to the consecutive shot mode and setting variably how to add an error correction code in response to the set compression rate. CONSTITUTION:A video signal or the like is given to a data compression and expansion circuit 12 via a digital signal processing circuit 10 to select the compressibility of data compression applied to a picture data in response to the consecutive shot mode and selects how to add an error correction code in response to the compressibility of data compression. Thus, in the case of consecutive shot, the data compression in response to the supply timing for each consecutive shot, that is, a picture data by one pattern (unit block) is applied and the redundancy of data is reduced in response to the data compressibility, then an error correction code is added accordingly to minimize the deterioration in the picture quality. Thus, the consecutive shot speed is improved while keeping a slow transmission speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a recording device for recording video signals and the like on a recording medium such as a magnetic tape.

[Prior Art] It has been generally known that various digital signals such as video signals and audio signals are recorded on a magnetic tape housed in a small cassette. The information signal is transmitted to a transmission system within the device at a predetermined transmission rate to perform processing such as signal processing and recording/reproduction.

[Problems to be Solved by the Invention] Incidentally, it is desirable that the signal transmission speed in the magnetic recording/reproducing device as described above be low in relation to various signal processing speeds.

However, if the transmission speed is made slower, the time required for recording becomes longer when recording a video signal with a large amount of information.

In other words, the transmission speed is 76, which is sufficient for transmitting audio signals.
8K bit/sec (2(ch) x 32(kH)
If you set about z)
It takes about 4.8 seconds to record a video signal of (640 (pixels) x 480 (pixels) x 1.5 (Y1C))]
It takes a lot of time.

For this reason, for example, when using a magnetic recording/reproducing device as described above as an electronic still camera, the shutter timing is restricted by the time required for recording, and video signals for multiple images must be recorded in a short period of time. The drawback is that the photo function (snapshot speed) is also limited.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned actual circumstances, and it is possible to solve the above-mentioned problems necessary to record relatively large amounts of data such as video signals while keeping the transmission speed suppressed. The purpose is to solve various inconveniences.

In order to achieve this object, the present invention provides a recording device that stores one screen worth of image data as a unit block and records each unit block on a recording medium, the unit block being compatible with continuous shooting mode. The compression rate of the compression process applied to the image data is variably set in accordance with the supply timing, and the manner in which an error correction code is added to the data is variably set in accordance with the set compression rate. Provide a recording device.

[Operation] According to the present invention configured as described above, it is possible to solve the inconvenience when handling data such as a large amount of video information at a slow transmission speed.

In other words, by switching the compression rate of data compression applied to image data according to the continuous shooting mode and switching the way of attaching error correction codes according to the compression rate of data compression, when performing quick shooting, the speed of quick shooting, that is, one screen Data compression is performed according to the supply timing of each image data (unit block), and data redundancy decreases according to the data compression rate, so image quality deterioration is prevented by adding an error correction code accordingly. It is possible to keep it to a minimum. Therefore, it is possible to improve the continuous shooting speed while keeping the transmission speed low.

[Examples] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of one embodiment of a magnetic recording device such as an electronic still camera to which the present invention is applied, and this embodiment is housed in a small cassette as shown in FIG. This is a device for magnetically recording digitized relatively large-capacity video signals or relatively small-capacity audio signals on magnetic tape.

The cassette C stores a magnetic tape Tp wound between a pair of tape reels disposed inside the cassette body as shown in FIG. It is designed to be visible to the outside world through. Further, a magnetic recording section 2 is formed on the side surface of this cassette C, and as described later, index information regarding the amount of recording recorded on the magnetic tape, etc. is recorded in this recording section 2. .

On the other hand, in this embodiment in which the magnetic tape in the cassette C as described above is used as the recording medium, the imaging light from the subject is passed through the optical system 3 having an aperture mechanism, an autofocus mechanism, etc. to a CCD (charge coupled device), etc. The resulting video signal is amplified by a predetermined amount in a preamplifier 5, and then sent to a switch circuit 6.
The signal is then converted into a digital signal with a predetermined number of bits by an A/D (analog/digital) converter 7. In addition,
The sampling frequency of this A/D converter 7 in this embodiment is the same as the driving frequency of the sensor 4, and the quantization hit is 8 bits. Further, in this embodiment, the audio input from the audio input device 6 such as a microphone is amplified by a predetermined amount in the preamplifier 9 and then passed through the switch circuit 6 to the A.
/D converter 7.

The digitized video signal or audio signal is subjected to predetermined signal processing in a digital signal processing device t (PSP) 10, and then temporarily stored in a memory circuit 11 having a storage capacity for at least one frame. The video signals etc. are sequentially read out and sent to the digital signal processing circuit l.
The data is supplied to the data compression/decompression circuit 12 via O, and after being subjected to data compression processing corresponding to continuous shooting mode or single shooting mode in which multiple images are taken continuously within a unit time, the data is supplied to the recording/reproducing section 13. The data is then recorded on the magnetic tape Tp inside the cassette mounted in the cassette mounting section.

Further, the recording/reproducing section 13 is supplied with data regarding the compression ratio from the compression ratio data generation/separation circuit 19, and this compression ratio data is recorded together with the image data at a predetermined position on the magnetic tape TP, for example, in the Saracoat area.

During reproduction, this compression rate data is separated from the reproduced image data by the compression rate data generation/separation circuit 19 and supplied to the system controller 20, which will be described later.

Here, the recording and reproducing section 13 includes a rotating tram 14 having two rotating heads He1 and He2 for recording and reproducing video signals and the like on the tape Tp,
When the cassette is installed in the cassette installation section of the recording/reproducing section 13, this rotating tram 14 moves inside the cassette C as shown in FIG. It is pressed against the tape.

As a result, in this embodiment, the magnetic tape is not coated with rope ink, and the outer periphery of the rotary drum 14 is approximately
It is possible to wrap it over an angular range of 00'.

The rotating tram 14 is inclined at a predetermined angle with respect to the longitudinal direction of the magnetic tape, and by rotating the rotating drum 14 and running the magnetic tape by a reel driving means (not shown), an image is recorded on the magnetic tape. Signals, audio signals, photographic information (index signals) to be described later, and the like are recorded diagonally. Note that a predetermined load is applied to the reel driving means 9, so that a predetermined contact pressure between the magnetic tape and the rotary head can be obtained.

On the other hand, during reproduction, the magnetic heads 11el, H
The playback output from e2 is supplied to the data compression/expansion circuit 12 via the recording/playback section 13, where it is subjected to predetermined error correction and data expansion processing as will be described later, and then sent to the DSP.
-l is stored in the memory circuit II via 10.

-t, the reproduced image data read out from the memory circuit 11 is supplied to the digital-to-analog (D/A) converter 17 via the DSP 10, where it is converted into an analog signal and then output to the output terminal. 18.

In addition, each of the above-mentioned parts in this embodiment includes a system controller (hereinafter referred to as "system controller") 2 using a microcomputer, etc.
The operation is controlled by 0.

This system controller 20 has a release switch SW connected to it.
In response to commands from various operation switches such as I, continuous shooting/single shooting changeover switch SW2, quick shooting mode setting switch SW3, playback switch SW4, and power switch SW5, the mote setting and operation control of each of the above-mentioned parts is performed.

That is, this system controller 20 controls each of the focus operation and iris operation in the optical system 3, and
It controls the conversion operations of the A/D converter 7 and the D/A converter 17, and also controls the switching in the switch circuit 6 and the writing and reading of the memory circuit 11, respectively.

The system controller 20 also outputs a continuous shooting/single shooting switching signal C/S and a continuous shooting speed switching signal H/L in response to the operation of the continuous shooting/single shooting changeover switch SW2 and the continuous shooting mode setting switch SW3. These switching signals C/S, H
/L controls the imaging operation (N light timing, etc.) of the sensor 4, the variable setting of the compression rate in the data compression circuit 12, and the setting control of the load amount of the correction code corresponding to the variable setting of the compression rate. The compression rate data generation/separation circuit 19 generates compression rate data regarding the data compression rate and the load amount of the error correction code based on these switching signals C/S and H/L, and supplies the data to the recording/reproducing section 13 .

Note that during reproduction, this compression rate data is separated and extracted from the reproduced image data and supplied to the system controller 20, and the system controller 20 controls the data compression/expansion circuit 12 and the like based on this compression rate data.

Further, the system controller 20 operates the power switch SW5.
The entire apparatus is set to the recording mode by the operation of the playback switch SW4, and the data compression/expansion circuit 12 and the compression ratio data generation/separation circuit 19 are set to the playback mode by the recording/playback switching signal R/P output in response to the operation of the playback switch SW4. Set.

Next, the operation of the data compression/expansion circuit 12 controlled by the above-mentioned switching signals C/S, l(/L, R/P) will be explained in detail with reference to its configuration and FIGS. 4 and 5.

FIG. 4 is a block diagram showing the configuration of the data compression/expansion circuit 12, and FIG. 5 is a diagram schematically showing the relationship between exposure timing and processing time in single shooting mode and continuous shooting mode in recording mode. be.

First, when recording an image in the single-shot mode, as shown in FIG. The signal is input to the switch SW6 which is switched by the continuous shooting/single shooting switching signal C/S, and is input to the first error correction circuit 21 via SW7. The first error correction circuit 21 is in a recording mode, and performs recording and reproduction by loading the same error correction code ECCl as when recording a normal audio signal to the uncompressed image data inputted from the switch SW6. Output to circuit 13.

On the other hand, during quick shooting, the image data input to the switch SW6 is input to the switch SW8, which is switched by the quick shooting speed switching signal H/L supplied from the system controller 20. The image data input to the switch SW8 is input to the first data compression/expansion circuit 22 during low-speed photography. At this time, the first data compression/expansion circuit 22 is in the recording mode, and as shown in FIG. 5(B), performs data compression using image redundancy on the image data input from the switch SW8. . Here, the first data compression/expansion circuit 22 compresses the data at a relatively low compression ratio, for example, about 1/4, and then passes through the switch SW9 switched by the switching signal H/L to the second error correction circuit 23. supply to. The second error correction circuit 23 is also in recording mode, and the first
By data compression by the data compression/expansion circuit 22,
Since the redundancy of the image data has decreased, in order to compensate for this, the second error correction circuit 23 applies a second error correction code ECC2 to the compressed image data supplied from the switch SW9.
is added and supplied to the switch SW.

During high-speed snapshotting, the image data input to the switch SW8 is supplied to the second data compression/expansion circuit 24. The second data compression/expansion circuit 24 is also in the recording mode, and as shown in FIG. 5(C), it also applies data compression using image redundancy to the image data input from the switch SW8. , the second data compression/decompression circuit 24 and the first
A compression rate higher than that of the data compression/decompression circuit 22 of
After the data is compressed to about /16, it is supplied to the third error correction circuit 25. The third error correction circuit 25 is also in recording mode, and the redundancy of the image data is further reduced due to data compression by the second data compression/expansion circuit 24. The error correction circuit 25 adds a third error correction code ECC5 to the highly efficient compressed image data inputted from the second data compression/expansion circuit 24 and supplies the data to the switch SW9.

As a result, during single shooting, data is not compressed, and data with the first error correction code ECC added is recorded; during low-speed continuous shooting, data is compressed with a low compression ratio, and the first and second error correction codes are The data added with the second error correction codes ECC1 and ECC2 are recorded, and data is compressed with a high compression rate during high-speed snapshot, and the data added with the second error correction codes ECC1 and ECC2 are recorded. The second and third error correction codes ECC1, 2, and 3 and the added data are recorded. Since the data compression rate differs depending on the continuous shooting mode while maintaining a slow transmission speed, the time required to record all image data also differs, and it is possible to correspond to the continuous shooting speed of each continuous shooting mode.

The first and second compression/expansion circuits 22 and 24 in this embodiment each include a data compressor and a data decompressor arranged in parallel with each other. Connections between the input and output terminals of the expansion circuits 22 and 24 are controlled by switching by the recording/reproduction switching signal R/P. Therefore, each compression/expansion circuit 22, 24 functions as a compressor in the recording mode, and functions as an expander in the reproduction mode.

Similarly, the first to third error correction circuits 21.23
．． 25 is also equipped with an error correction code adder (encoder) and a correction circuit (decoder), and these are also switching-controlled by the recording/reproduction switching signal R/P, and function as an encoder in the recording mode, and function as an encoder in the reproduction mode. Sometimes it functions as a decoder.

In addition, in this embodiment, the first and second compression/expansion circuits 22 and 24 and the first to third error correction circuits 21
, 23.25 are driven at the same transmission speed.

Next, when playing back, the first, second, and third error correction circuits and the first and second data compression/expansion circuits are set to playback mode by the switching signal R/P supplied from the system controller 20. There is. The reproduced image data reproduced from the magnetic tape Tp and output from the recording/reproducing circuit 13 is input to the first error correction circuit 21, where data errors caused by the magnetic recording/reproducing are corrected based on the correlation between the correction code and the data. It is supplied to SW7. The image data input to the switch SW7 is switched by a switching signal C/S supplied from the system controller 20 based on the compressed data extracted from the reproduced image data when a single-shot image is reproduced, and is converted into digital data through the switch SW6. Signal processing circuit lO
is supplied to

On the other hand, when reproducing a snapshot image, the image data input to the switch SW7 is supplied to the second error correction circuit 23. After the second error correction circuit 23 corrects data errors that could not be corrected by the first error correction circuit 21 due to reduction in redundancy of image data due to data compression, the switch SW9
supply to. The image data input to the switch SW9 is sent to the first data compression/expansion circuit 2 when a low-speed photographed image is reproduced.
2 is input. The first data compression/decompression circuit 22 performs data decompression using image redundancy on the image data inputted from the switch SW7, and then decompresses the image data inputted from the switch SW7.
．． The signal is supplied to the digital signal processing circuit IO via SW6.

When reproducing a high-speed snapshot image, the image data input to the switch SW9 is supplied to the third error correction circuit 25. The third error correction circuit 25 processes data that could not be completely corrected by the second error correction circuit 23 in order to further reduce the redundancy of the image data due to data compression by the second data compression/decompression circuit 24. The error is corrected and the data is supplied to the second data compression/expansion circuit 24. The second data compression/expansion circuit 24 also performs data expansion using image redundancy on the image data supplied from the third error correction circuit 25, and switches SW8. The signal is supplied to the digital signal processing circuit IO via SW6.

As is clear from the above description, according to this embodiment, it is possible to solve the inconvenience when handling a large amount of video information at a slow transmission speed.

In other words, by switching the compression rate of data compression applied to image data according to the continuous shooting mode, and changing the method of attaching error correction codes according to the compression rate of data compression, when performing quick shooting, the data is processed according to the speed of quick shooting. By performing compression and adding an error correction code according to the data compression rate, it is possible to suppress the image deterioration that accompanies the high efficiency of the compression process to a small degree. Therefore, according to this embodiment, it is possible to improve the continuous shooting speed in situations where image deterioration is suppressed while maintaining a slow transmission speed.

Incidentally, in the above embodiment, the error correction circuit in the data compression/expansion circuit 10 was provided on the 38th floor, and the error correction code was applied in a different manner by cumulatively using these error correction circuits depending on the operation mode. However, the present invention is not limited to such a configuration, and may be configured to selectively use a plurality of error correction circuits with different error correction powers and operation modes, for example.

In addition, in this embodiment, the image data is not compressed when recording in single-shot mode, and it is natural that compression may be used in this case as well, and in that case, it is possible to save on recording media such as magnetic tape It is possible to aim for

[Effects of the Invention] As is clear from the above description, according to the present invention, unit blocks of a predetermined amount of data are recorded as blocks, and the supply timing of each block is different depending on the mode. By recording the data while varying the compression rate, it is possible to record each block of data within the interval of the supply timing.

Further, according to the present invention, by changing the method of adding error correction according to the compression rate that is variably set as described above, it is possible to prevent deterioration of image quality depending on the compression rate.

Furthermore, when such an invention is applied to a recording device having a rapid shooting function and a single shooting function, the continuous shooting function is not degraded, and image deterioration can be minimized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a recording device according to the present invention, FIG. 2 is a perspective view showing a cassette according to the present invention, FIG. 3 is a schematic plan view showing main parts of a cassette mounting section, and FIG. The figure shows the configuration of the data compression/expansion block of the recording device according to the present invention, and FIGS. 5(A), 5(B), and 5(C) are time charts schematically showing the relationship between exposure timing and processing time during recording. It is. 3 is an optical system, 4 is a sensor, 7 is an A/D converter, 8 is an audio input means, 10 is a digital signal processing circuit, 11 is a memory circuit, 13 is a recording/reproducing unit, 20 is a system controller, and 12 is data compression Extension block, 21, 23.2
5 is an error correction circuit, and 22.24 is a data compression/expansion circuit. 1st @ chapter / E Shu 51 drawing f job cf-7

Claims (1)

[Scope of Claim] A recording device that records image data for one screen as a unit block on a recording medium in units of unit blocks, wherein the above-mentioned image data is recorded on a recording medium in accordance with the supply timing of the unit blocks corresponding to a continuous shooting mode. A recording device characterized in that a compression rate of compression processing applied to image data is variably set, and a method of attaching an error correction code to the data is variably set according to the set compression rate.