JPH03201886A - Electronic camera - Google Patents

Abstract

PURPOSE:To record a still picture signal and an audio signal simultaneously by applying data compression to a picture signal with discrete cosine (DCT) transformation, applying partial response processing to the picture signal subject to data compression and recording the signal onto a magnetic tape together with the audio signal. CONSTITUTION:An audio stereo signal is recorded on recording tracks T1, T2 of a magnetic tape MT, a still picture signal is recorded on remaining recording tracks T3, T4, and the still picture signal and the audio signal are recorded and reproduced only when all the tracks T1-T4 are driven in one direction of the arrow. Then the still picture signal is compressed by the DCT transformation and recorded with high density on two tracks of the magnetic tape MT with the partial response processing and an analog stereo audio signal is recorded on the remaining two tracks. Thus, the high density recording is attained and the picture signal and the audio signal are recorded simultaneously on the magnetic tape MT.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic camera capable of recording and reproducing digital image signals such as still images and analog audio signals on a magnetic tape such as an audio cassette tape.

[Prior Art] Conventionally, most photographs have been silver halide photographs in which image information is printed onto photographic paper, but recently electronic cameras that store image information electronically are being put into practical use.

Until now, electronic cameras were designed to record only image information, but recently it has become possible to record image information and audio signals at the same time, for example, while recording the content of a meeting. There are also plans to take photos of attendees.

[Problem to be solved by the invention In] However, recording image information and audio signals at the same time requires recording a large amount of data, which leads to an increase in the size of the camera itself and increases the cost. It also had the disadvantage of being expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic camera that can simultaneously record still image signals and audio signals using a magnetic tape such as an audio cassette tape.

[Means for Solving the Problems] The present invention compresses an image signal input from an image signal input means by discrete cosine transformation, performs partial response processing on the compressed image signal, and converts the image signal into an audio signal. It is also recorded on magnetic tape.

In addition, partial response demodulation processing is performed on the partial response processed image signal played back from the magnetic tape, and further, inverse discrete cosine transformation is performed on the demodulated image signal, and the resulting image signal is played back from the magnetic tape. It is designed to be output together with the recorded audio signal.

[Function] According to the present invention, high-density recording is possible by compressing image signals by discrete cosine transformation and further performing partial response processing, and recording image signals and audio signals simultaneously on a magnetic tape. be able to.

Further, by performing partial response demodulation processing on the image signal reproduced from the magnetic tape and further performing inverse discrete cosine transformation, it is also possible to reproduce an image faithful to the original image.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the same embodiment. In the figure, reference numeral 1 denotes an optical lens, and an image input through the optical lens 1 is input to an imager 2. The imager 2 is made of a charge-coupled device (COD) and is driven by a dedicated driver (not shown) to output an image signal.

The image signal from the imager 2 is amplified by a preamplifier 3 and provided to an A/D converter 4. This A/D converter 4
converts the image signal output from the preamplifier 3 into digital image data and outputs the digital image data.

Digital image data from the A/D converter 4 is sent to a signal processing section 5. This signal processing section 5 performs processing to separate the R and GSB signals into Y, RY, and BY signals. Then, Y, R processed by this signal processing section 5
The -YSB-Y signal is written into the field memory 6.

Here, YlR-YS written in the field memory 6
The BY signal is converted into an analog signal through a D/A converter 7 and encoded by an encoder 8 so that it can be reproduced on a television screen as a video output.

The field memory 6 inputs the YSR-YSB-Y signal to D.
CT/D CT-' Provided to the converter 9 to perform DCT (discrete cosine) conversion;
The CT~1 conversion unit is provided with an output that has been inversely transformed by DCT.

Here, the DCT/DCT-' conversion unit 9 divides one screen into blocks of 8x8 pixels, for example, as shown in FIG. 2(a), and performs DCT transformation on these 8x8 pixel blocks. Do it like this. Here, DCT transformation is one of the orthogonal transformations, and it divides a certain waveform into frequency components and expresses them as cosine waves with the same number of input samples.
For a block of ×8 pixels, energy is concentrated by performing DCT transformation processing on each row and column, and compression of image data is made possible by encoding only the components with a large amount of energy. As a result, when a block of 8×8 pixels is subjected to DCT transformation,
Energy concentration is obtained around the DC component portion shown in a of FIG. 2(b), and data compression of the image signal can be realized by encoding only this high-energy component.

The DCT-transformed output by the DCT/DCT-1 converter 9 is sent to the quantization block 10. The quantization block 10 deletes harmonic component data of the DCT transform output. The output of the quantization block 10 is then sent to the encoding/decoding block 11, where it is outputted as image data with little redundancy mainly consisting of DC components through encoding processing such as run length. Here, the output encoded by the encoding/decoding block 11 may be given to an error correction block (not shown), and after adding parity or the like, it may be output to the next stage.

The output encoded by the encoder/demodulator block 11 is
It is supplied to the PR (partial response) side. first,
The output of the encoding/decoding block 11 is sent to the bricoding section 12. Here, if an error occurs during decoding, the error propagates to subsequent data detection, so the precoding unit 12 performs data conversion to prevent this error propagation only to that data.

The data precoded by the precoding section 12 is given to the PR modulation section 13.

The PR modulator 13 has the functions of waveform convolution and pilot signal superimposition, and as shown in FIG. It consists of 137 adders. Here, as shown in FIG. 4(a), the waveform ROM 131 stores in advance three waveforms a, which have different peak values corresponding to the input data.
b.

A data string corresponding to C is stored. And the waveform R
Based on the output of OMI 31, calculation results consisting of di ω0, d1ω1, ... dl 0M-1 are obtained for input data di, and these M calculation results are added in the manner shown in Fig. 5. , Xl-Σdl-jωj. Here, ω
0, ω11, . . . are waveform elements of the waveform ROM 131. That is, the output of the waveform ROMI 31 is given to the adder 134. The adder 134 connects the output of the waveform ROM 131 to
The contents of the addition memory 133 in which the previous addition results are stored are added, and the result ADj (where j−〇,
1,...) is output. Then, ADO of the output of the adder 134 is given to the latch 135, and this latch 135
The pilot signal shown in FIG. 4(b) outputted from the pilot ROM 136 is superimposed on the output of the pilot ROM 136 by an adder 137, and outputted as a PR signal. In addition, the outputs ADL, AD2, . . . of the adder 134 other than the output ADO are as follows.
The data is written into the addition memory 133, and the above-described operations are repeated in order to output the PR signal.

The PR signal of the PR modulation section 13 is given to the D/A converter 14, where it is converted into an analog signal, and the PR signal is sent to the analog circuit 1.
The data is recorded on the magnetic tape by the recording head 16 via the magnetic tape 5.

On the other hand, the PR signal recorded on the magnetic tape is taken out from the reproducing head 17 and sent to the A/D via an analog circuit 18.
It is converted into a digital signal by one converter. and,
The PR signal digitized by the A/D converter 19 is PR
The signal is sent to the demodulator 20.

The PR demodulation section 20 includes a digital filter 201, a delay memory 202, and a data detection section 203, as shown in FIG. Here, the digital filter 201 extracts a pilot signal from the digitized PR signal. The delay memory 202 delays the PR signal applied via the digital filter 201 by a predetermined period of time and provides the delayed PR signal to the data detection section 203 together with the pilot signal.

The data detection section 203 performs PR based on the pilot signal.
The original encoded signal is detected from the signal.

The encoded signal demodulated by the PR demodulator 20 is coded/
The data is sent to the decoding block 11 and decoded, and then the data is decompressed in the quantization block 10.
It is sent to the CT-' converter 9. And DCT/DCT
-' The conversion unit 9 performs inverse DCT transformation, restores approximate data of the original image according to the quantization level, and writes it into the field memory 6.

Note that 21 is a key input unit, and 22 is a CPU.

Here, the CPU 22 outputs commands to control each circuit.

Next, FIG. 7 shows an audio recording circuit, in which an audio signal is applied from an input terminal 30 to a recording level adjustment circuit 31, and sent to a recording controller 34 through amplifiers 32 and 33. A noise reduction circuit 35 and a recording equalizer circuit 36 are connected to the amplifier 33, a bias oscillator 38 is connected to the recording head 34 via a bias adjustment circuit 37, and an erase head 39 are connected.

Next, FIG. 8 shows a reproducing circuit, in which the reproducing head 4
The output from 1 is output to output terminal 45 through amplifiers 42, 43, and 44. A reproduction equalizer circuit 46 is connected to the amplifier 42, and a noise reduction circuit 47 is connected to the amplifier 44.

Next, the operation of the embodiment configured as described above will be explained.

Now, when an image is input through the optical lens 1,
The signal is input to the imager 2 and output as an image signal.

The image signal from the imager 2 is amplified by a preamplifier 3, fed to an A/D converter 4, converted into digital image data, and output.

This digital image data is then sent to the signal processing section 5, where processing is performed to separate the R and GSB signals into Y and R-YSB-Y signals.

The Y, RY, and BY signals processed by the signal processing section 5 are
The data is written to the field memory 6. In this case, the Y, R-YSB-Y signals written in the field memory 6 are
The signal is supplied to the A converter 7, where it is converted into an analog signal, and then encoded by the encoder 8, such as superimposing a synchronization signal, so that it can be reproduced on a television screen.

On the other hand, YlR-Y written in the field memory 6,
The B-Y signal is given to the DCT/DCT-' converter 8. The DCT/DCT-' conversion unit 8 divides the image into subblocks of 8×8 pixels as described above, and performs DCT transformation on the rows and columns of these subblocks. The DCT-transformed output is then sent to a quantization block 10, where harmonic component data of the DCT-transformed output is deleted, and further, an encoding/decoding block 11
The image data is sent to the computer, and is output as image data with less redundancy, mainly consisting of DC components, through encoding processing such as run length.

The output encoded by the encoder/demodulator block 11 is
It is sent to the bricoding section 12. Then, after being subjected to bricoding processing, the signal is provided to the PR modulation section 13. In the PR modulation section 13, the waveform ROM 131 outputs waveform data corresponding to input data. Waveform ROM
The output of I 31 is provided to adder 134. The adder 134 adds the contents of the addition memory 133 in which the previous addition results are stored to the output of the waveform ROMI 31, and as a result ADj (however, j-0, 1, . . . )
is output.

Of the outputs of the adder 134, ADO is the latch 13
5 to the adder 137 through the pilot ROM
136 pilot signals are superimposed. Also, adder 1
34 outputs ADI other than ADO AD2,...
. is written in the addition memory 133, and the above-described operation is repeated and output as a PR signal.

The PR signal output from the PR modulation section 13 is given to a D/A converter 14, where it is converted into an analog signal, and recorded on a magnetic tape by a recording head 16 via an analog circuit 15. In this case, the image data is recorded on recording tracks T3 and T4 of the magnetic tape MT shown in FIG.

Next, reproduction of the image data is a reverse operation to that described above, and the PR signal recorded on the magnetic tape is transferred to the reproduction head 17.
The analog circuit 18 and the A/D converter 19
is converted into a digital signal and sent to the PR demodulation section 20.

In the PR demodulation section 20, a pilot signal is extracted from the PR signal via a digital filter 201. On the other hand, PR
The signal is delayed by a delay memory 202 for a predetermined time,
The PR signal is given to data detection section 202 together with the pilot signal, and the original encoded signal is detected from the PR signal based on the pilot signal.

The encoded signal demodulated by the PR demodulator 20 is coded/
The data is sent to the decoding block 11 and decoded, and then the data is decompressed in the quantization block 10 and subjected to DCT/DCT.
-1 is sent to the converter 9. And DCT/DCT-1
The conversion unit 9 performs inverse DCT transformation to restore approximate data of the original image according to the quantization level, and stores it in the field memory 6.
written to. In this state, the approximation data of the original picture written in the field memory 6 is given to the D/A converter 7, converted into an analog signal, and then encoded by the encoder 8 to reproduce a still TV screen. can.

On the other hand, for audio related to still images, the audio recording circuit shown in FIG. 7 and the playback circuit shown in FIG.
Recording and reproduction in stereo is carried out using analog signals on the recording tracks Tl and T2 of the magnetic tape MT shown in the figure. In this case, these audio recording circuits and playback circuits are
Since this is well known, the explanation of its operation will be omitted here.

As a result, the magnetic tape MT has recording tracks Tl,
Audio signals are recorded in stereo on T2, and still image signals are recorded on the remaining recording tracks T3 and T4, and still images and Audio will now be recorded and played back.

Therefore, in this way, data can be compressed from a still image signal by DCT conversion, high-density recording can be performed on two tracks of the magnetic tape MT by partial response processing, and analog stereo audio signals can be recorded on the remaining two tracks. As a result, it is possible to realize a small and inexpensive electronic camera. In addition, in this case, the recording track TI of the magnetic tape MT,
By extracting only the audio signal recorded on T2, it is possible to reproduce stereo audio in the same way as a conventional stereo audio cassette, and it is also possible to use the media effectively.

[Effects of the Invention] The present invention compresses the image signal input from the image signal input means by discrete cosine transformation, performs partial response processing on the compressed image signal, and records the data on the magnetic tape along with the audio signal. This makes it possible to perform high-density recording, and it is possible to simultaneously record image signals and audio signals on a magnetic tape such as a general audio cassette tape.

In addition, partial response demodulation processing is performed on the partial response processed image signal played back from the magnetic tape, and further, inverse discrete cosine transformation is performed on the demodulated image signal, and the resulting image signal is played back from the magnetic tape. Since the image is output together with the audio signal, it is possible to reproduce an image that is faithful to the original at the same time as the audio signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention, FIG. 2 is a diagram for explaining discrete cosine transform used in the embodiment, and FIG. 3 is a block diagram showing the circuit configuration of an embodiment of the present invention. 4 is a diagram showing a waveform data string and a pilot signal used in the PR modulation section; FIG. 5 is a diagram for explaining convolution of the PR modulation section; FIG. 6 is a block diagram showing a PR demodulation section used in the same embodiment, FIG. 7 is a circuit diagram showing an audio recording circuit used in the same embodiment, and FIG. 8 is an audio reproduction circuit used in the same embodiment. FIG. 9, a circuit diagram showing the circuit, is a diagram for explaining the recording state on the magnetic tape. 1... Optical lens, 2... Imager, 5... Signal processing section, 6... Field memory, 9... DCT
/D CT-1 converter, 10...quantization block, 1
DESCRIPTION OF SYMBOLS 1... Encoding/decoding block, 13... PR modulation part, 16... Recording head, 17... Reproducing head,
20...PR demodulator. Figure 2 PR4 No. 3 Figure 6

Claims (2)

[Claims] (1) an image signal input means; a discrete cosine transform means for data-compressing the image signal input from the image signal input means by discrete cosine transform;
It is equipped with a partial response processing means that performs partial response processing on the image signal data compressed by the discrete cosine conversion means, and a recording means that records the image signal subjected to the partial response processing on a magnetic tape together with the audio signal. An electronic camera characterized by: (2) reproducing means for reproducing an image signal that has been subjected to partial response processing recorded on a magnetic tape; demodulating means for performing partial response demodulation processing on the image signal reproduced by the reproducing means; The present invention includes an inverse discrete cosine transform means for inverse discrete cosine transform of a demodulated image signal, and an image/audio output means for outputting the image signal output from the inverse discrete cosine transform means together with the audio signal reproduced from the magnetic tape. An electronic camera featuring