JP3490738B2 - Image signal processing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal processing device provided in a still video device, and more particularly for recording an image signal of a high definition television (HDTV) system or the like on a recording medium such as a magnetic disk. The present invention relates to an image signal processing device for converting an image signal according to a standard television system or the like.

[0002]

2. Description of the Related Art Conventionally, a still video device is usually configured to record an image signal of a standard television (for example, NTSC system) on a track of a magnetic disk according to a still video format, and the band width of this signal is wide. However, the size cannot be increased without limit due to the structure of the disk device. Therefore, even if a high-quality or wide-band image signal is input to the still video device, the resolution of the image is limited and the image quality is deteriorated. Therefore, in the Japanese Patent Application No. 3-268104, the applicant divides an image signal corresponding to one screen into a plurality of pixel signals as a still video device for recording a high-definition image according to the HDTV system on a magnetic disk. In addition to thinning out, we proposed to extend the time axis and record on the track. That is, in this still video device, when the image signal corresponding to one screen is divided into two, for example, in the frame recording mode, the image signal of one screen is recorded on four tracks.

[0003]

The number of effective scanning lines of an image signal according to the high-definition system which is one of the HDTV systems is 1035 lines, and when this is divided into four tracks and recorded, it is recorded on one track. The number of scanning lines to be made is about 259. But with still video devices,
In the case of the NTSC system, the number of effective scanning lines per track of the magnetic disk is 241.5, and therefore the HDT
It is not possible to record all V-system image signals on a magnetic disk. The difference in the number of effective scanning lines based on the difference in this method will be described below with reference to FIGS. It should be noted that these figures show an example in which one screen recorded by the high-definition system is vertically divided into two and recorded on the magnetic disk by the NTSC system.

As shown in FIGS. 10 and 12, with respect to the upper half of one screen, the image of the first field of the high-definition system is 2 by the NTSC system on the magnetic disk.
The image is recorded from 2H (H is a horizontal scanning period) to 263H, and the image of the second field of the high-definition system is recorded from 284H to 525H on the magnetic disk by the NTSC system. The image of the first field of the high-definition system is recorded on the first track, and the image of the second field is recorded on the second track. In the lower half of the screen, the HDTV first field image is recorded from 284H to 525H on the magnetic disk, and the HDTV second field image is recorded from 22H to 263H. The image of the first field of the high-definition system is recorded on the third track, and the image of the second field is recorded on the fourth track.

The horizontal scanning line of the high-definition system is NT
When it corresponds to the horizontal scanning line of the SC system, as can be understood from FIGS. 11 and 12, the image of the first field by the HDTV system is recorded only from 41H to 523H, and the images of 524H to 557H are recorded on the magnetic disk. Is not recorded. 603H for the second field
From 1087H to 1 is recorded.
The 120H image is not recorded on the magnetic disk.

In view of the above problems, the present invention provides H
An image signal according to an image signal processing method, such as a DTV method, in which the number of horizontal scanning lines per field is relatively large,
The object of the present invention is to provide an image signal processing device capable of recording on a recording medium such as a magnetic disk as much as possible.

[0007]

An image signal processing apparatus according to the present invention processes an image signal generated by a first image signal processing method in which the number of horizontal scanning lines per field is relatively large. An image signal processing apparatus for generating an image signal according to a second image signal processing method, wherein the number of horizontal scanning lines per field is relatively small, and the image signal according to the first image signal processing method. a memory for Case <br/> pay a relatively high frequency, from the memory, the second image signal processing
Read out image signal at relatively low frequency according to the method
And the read operation is during the vertical blanking period of the image signal.
Recording the image signal on the recording medium
A recording means is provided.

[0008]

[0009]

The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a block diagram of a recording system of a still video device to which an embodiment of the present invention is applied.

The system control circuit 10 is a microcomputer and controls the entire still video apparatus. The disk device has a magnetic head 11 and a spindle motor 12 for rotationally driving the magnetic disk D. The magnetic head 11 is tracking-controlled by the system control circuit 10 and is displaced along the radial direction of the magnetic disk D. The spindle motor 12 is drive-controlled by the system control circuit 10 and rotates the magnetic disk D at a rotation speed of 3600 rpm, for example. While the magnetic disk D is rotating, the magnetic head 1
1 is located on a predetermined track of the magnetic disk D, and an image signal and an ID code are recorded on this track. The recording amplifier 13 is controlled by the system control circuit 10 and outputs an image signal and the like to the magnetic head 11. In addition,
The magnetic disk D has 52 tracks, and signals such as image signals are recorded on 50 tracks counting from the outermost track to the inner track.

An operation unit 14 connected to the system control circuit 10 is provided for operating the present still video device. The ID code relating to the image recorded on the magnetic disk D, that is, the data such as the recording mode and the shooting date is also input through the operation unit 14. When a recording mode for converting an HDTV system image signal into a standard television system image signal is selected by the operation of the operation unit 14, information indicating that the recording track is recorded in such a recording mode is ID. The code is added to the user's area and recorded on the magnetic disk.

A high-quality image signal obtained by a still video camera (not shown) or an external input terminal (not shown) includes two color difference signals (RY, BY) and a sync signal. A still luminance signal (Y + S) is input to the still video device. The sync signal (S) is a composite sync signal including a horizontal sync signal, a vertical sync signal, and an equivalent pulse. In the figure, the symbol (H) attached to the luminance signal and the color difference signal means a wide band, that is, high image quality. The sync signal S included in the brightness signal (Y + S) is separated from the brightness signal (Y + S) by the sync signal separation circuit 21 and sent to the memory control circuit 22 and the system control circuit 10. The memory control circuit 22 is
Based on the synchronization signal S, the AD converters 23, 24, 25,
Y memory 26, RY memory 27 and BY memory 2
Control eight. Further, the memory control circuit 22 is based on a synchronizing signal from a synchronizing signal generating circuit 34 described later, and DA converters 31, 32, 33, Y memories 26, R-.
It controls the Y memory 27 and the BY memory 28.

The luminance signal (Y + S) including the synchronization signal is A
The luminance signal Y, which is AD-converted by the D converter 23 and is recorded between the two horizontal synchronizing signals, is stored in the Y memory 26 under the control of the memory control circuit 22. Similarly, the color difference signal (RY) is AD-converted by the AD converter 24.
It is converted and stored in the RY memory 27. The color difference signal (BY) is AD-converted by the AD converter 25,
It is stored in the BY memory 28.

Y memory 26, RY memory 27 and B
-Y luminance signal Y and color difference signal (R
-Y, BY) are DA-converted by DA converters 31, 32, and 33, respectively, based on the synchronization signal (reference clock signal) output from the synchronization signal generation circuit 34.
At this time, the reference clock signal is the memory 26, 27, 28.
It has, for example, half the frequency of the reference clock signal used to record the image signal. Therefore, the image signal is read out from each of the memories 26, 27 and 28 at a relatively slow speed, and the time axis is expanded thereby. Now, the DA converted luminance signal Y is Y
It is input to the recording processing circuit 35 and subjected to processing such as FM modulation. Two DA-converted color difference signals (RY, B-
Similarly, Y) is also input to the C recording processing circuit 36 and subjected to processing such as FM modulation.

The ID code input via the operation unit 14 and the system control circuit 10 is subjected to processing such as DPSK modulation in the ID recording processing circuit 37.

The DPSK-modulated ID code, the FM-modulated luminance signal, and the color-difference signal are superimposed by the adder 38, amplified by the recording amplifier 13, and sent to the magnetic head 11. Then, the ID code, the luminance signal and the color difference signal are recorded on a predetermined track of the magnetic disk D by the magnetic head 11. As described above, the signal recorded on the magnetic disk D is expanded in the time axis as compared with the signal input to the still video device.

In the present embodiment, the image signal input to the still video device is sub-sampled (thinned) and stored in the memories 26, 27 and 28, and time-axis expanded and read from the memories 26, 27 and 28. And recorded on the magnetic disk D. This will be described with reference to FIGS. In this example, the input image signal is recorded in the frame recording mode, and the number of scanning lines and the line frequency of the input image are determined according to the HDTV system (high definition system).

FIG. 2 is a diagram showing the relationship between subsampling and interpolation. In this figure, the band of the input image signal is f _H
This image signal is stored in the memories 26, 27 and 28 by thinning out half the pixels by subsampling. When reproducing this image signal, the image signal is interpolated by a known method, whereby the decimated image signal is substantially reproduced, and an image having the same image quality as the input image is obtained.

In FIG. 2, for the pixel in the first field, the pixel at the leftmost end of the screen is sampled, the next pixel is decimated, and so on, every other pixel is sampled. . On the other hand, with respect to the pixels in the second field, the pixels at the leftmost end of the screen are thinned out, the next pixel is sampled, and so on, every other pixel is sampled. In this way, the pixels of the input image signal are thinned out evenly on the screen.

FIG. 3 shows the relationship among the input image signal, the image signal recorded on the memory, and the image signal recorded on the magnetic disk D. In this figure, the band of the input image signal K is f _H , but the image signal stored in the memory is sub-sampled, so that the band of the image signal becomes f _H / 2. The image signals of the first field and the second field are stored in the memories 26, 27, 28 in the first to the first fields.
It is divided and stored in the fourth area. That is, the image signal corresponding to the upper screen of the first field is the first signal of the memory.
The image signal stored in the area and corresponding to the lower screen of the first field is stored in the third area of the memory. The image signal corresponding to the upper screen of the second field is stored in the second area of the memory, and the image signal corresponding to the lower screen of the second field is stored in the fourth area of the memory. The image signals stored in the first to fourth areas are the magnetic disk D.
Is recorded on each of the first to fourth tracks.

The image signal stored in the memory is doubled on the time axis when recorded on the magnetic disk D, whereby the band of the image signal becomes f _H / 4. Therefore HD
Even the input image signal according to the TV system is written on the magnetic disk D by the still video device while maintaining high image quality.

FIG. 4 shows a flowchart of the operation of the memory control circuit 22, that is, a program for dividing the input image signal into two and storing it in the memory as shown in FIG. ing.

[0023] At step 101, the memory clock is set at approximately the same frequency f _'SH and band f _H of the input image signal. This memory clock is equal to an integral multiple of the horizontal line frequency of the input image, and is generated based on the reference clock signal output from the synchronization signal generation circuit 34. The reason why the frequency of the memory clock is set to be an integral multiple of the horizontal line frequency of the input image is to allow the clock signal to rise at the left end of the screen, and as a result, as will be described later, regarding the first field. , Odd-numbered pixels counted from the left end of the screen are sampled.

In step 102, the first field of the input image is AD-converted based on this memory clock, and all the image signals of the first field are stored in the memories 26 and 2.
7 and 28 are written. This write operation will be described with reference to FIG. In FIG. 11, the vertical synchronizing signal corresponds to the pulse signal indicated by the symbol VS, and the signal MS corresponding to the 41st horizontal scanning period counted from the first pulse signal F1 is the first horizontal scanning line of the first field. (Image signal). In step 102, the 41st signal MS to the 557th signal ML are stored in the memory as image signals. Memory control circuit 2
2 recognizes the timings of the signals F1, MS and ML shown in FIG. 11 according to the sync signal output from the sync signal separation circuit 21. According to this timing, the image signal is AD converted, and 517 horizontal scanning lines are stored in the memory 2
6, 27, and 28.

At step 103, the memory clock is inverted. The rising time and the falling time of the memory clock are equal to each other. Therefore, in step 103, a clock signal which is shifted by a half cycle from the memory clock set in step 101 is generated. In step 104, the second field of the input image is AD converted based on the memory clock set in step 103 and written in the memories 26, 27 and 28.

The operation of writing the image signal to the memory in steps 102 and 104 will be described with reference to FIG. Sampling of pixels of the image signal is performed at the rising edge of the clock signal. Therefore, as indicated by the symbol L, in the first field, the odd-numbered pixels counted from the left end of the figure are sampled, and the second pixel is sampled.
In the field, even-numbered pixels counting from the left end of the figure are sampled. The pixels of the first field sampled in this way are stored in the first and third areas of the memory, and the pixels of the second field are stored in the second and fourth areas of the memory.

[0027] In step 105, the memory clock is set to a frequency f _'SL. The frequency f _'SL is the clock signal for writing the input image signal in the memory the frequency f' _SH
Is a half of the line frequency of the still video and is an integral multiple of the line frequency of the still video. The reason why the frequency of the memory clock is set to an integral multiple of the line frequency of the still video is to accurately determine the relative position of the sync signal and the image signal on the magnetic disk.

At step 106, the counter N is "1".
Is set to. In step 107, the magnetic head 11
Is tracked to the Nth track. Then, in step 108, the image signals of the Nth area of the memories 26, 27 and 28 are read at the timing of the frequency f ′ _SL and recorded on the magnetic disk D. In this operation, the synchronization signal generation circuit 34 outputs the vertical synchronization signal, and at the timing of the 10th horizontal scanning period counted from the start of the vertical blanking period (see FIG. 6), the 41st signal MS (see FIG. 6). 11
Is recorded on the magnetic disk D. Then, the 42nd signal to the 294th signal are recorded on the magnetic disk D. That is, 254 horizontal scanning lines are recorded on the magnetic disk D.

In this way, the memory control circuit 2
2 starts reading the image signals from the memories 26, 27, and 28 at the timing when the image signal is not read from the memory in the conventional apparatus, whereby more image signals than those recorded by the conventional apparatus are recorded on the magnetic disk D. Recorded in. That is, the memory control circuit 22
10th or 2 from the beginning of the vertical blanking period
At the timing of the 72nd horizontal scanning period, the reading of the image signal from the memory and the DA conversion are started.

At step 109, the counter N is incremented by 1, and at step 110, it is judged if the counter N is "4" or less. If the counter N is "4" or less, the reading of the image signals of all the areas on the memory has not been completed, and therefore steps 107 and subsequent steps are executed again. On the other hand, when the counter N exceeds "4", the reading of the image signals of all the areas on the memory is completed, and this program is completed.

As described above, in the loop of steps 107 to 110, when the counter N is "2", the image corresponding to the 603rd to 856th horizontal scanning lines in the upper half of the second field of the HDTV system. The signal is recorded on the second track of the magnetic disk. When the counter N is “3”, the lower half of the first field is 29
Image signals corresponding to the fifth to 547th horizontal scanning lines are recorded on the third track of the magnetic disk. When the counter N is "4", the image signals corresponding to the 857th to 1110th horizontal scanning lines in the lower half of the second field are recorded on the fourth track of the magnetic disk.

Now, in writing the image signals in the memories 26, 27 and 28 in steps 102 and 104 and recording the image signals in the magnetic disk D in step 108, the number of horizontal scanning lines per field is 50.
The number is 7, which is 24 more than the conventional device. This increase in horizontal scanning lines will be described below with reference to FIGS. 6 and 7.

As described with reference to FIG. 3, these figures show an example in which one screen recorded by the high-definition system is vertically divided into two and recorded on the magnetic disk according to the NTSC system.

As shown in FIG. 6, for one half of one screen,
The image of the first field is recorded from 10H to 263H, and the image of the second field is recorded from 272H to 525H. 1H to 21H and 263H to 28
4H is the vertical blanking period, and among them, 1
0H to 21H and 272H to 284H are horizontal scanning periods which are conventionally used for transmitting data in teletext. In this embodiment, 10H to 21H and 272H to 284H in the NTSC system are
Used for recording image signals.

The relationship between each horizontal scanning line and the screen will be described with reference to FIG. 7. Regarding the upper half of one screen, the image of the first field of the high-definition system is N on the magnetic disk.
It is recorded from 10H to 263H by the TSC system, and the image of the second field of the high-definition system is recorded from 272H to 525H on the magnetic disk by the NTSC system. The image of the first field of the high-definition system is recorded on the first track, and the image of the second field is recorded on the second track. In the lower half of the screen, the HDTV first field image is recorded on the magnetic disk from 272H to 525H by the NTSC system, and the HDTV second field image is
On the magnetic disk, from 10H to 26 by NTSC method
It is recorded by 3H. The image of the first field of the high-definition system is recorded on the third track, and the image of the second field is recorded on the fourth track.

The high-definition horizontal scanning line is set to NTSC.
As can be seen from FIG. 7, when corresponding to the horizontal scanning line of the H.S.A. system, 41H to 547H are recorded in the image of the first field according to the HDTV system, and the H.S. It has increased by 24. Similarly for the second field, 603
H to 1110H are recorded, and the number of horizontal scanning lines recorded on the magnetic disk is increased by 24 lines as compared with the conventional device.

The image signal by the high-definition system is NTS
When recording on a magnetic disk by the C method, 35 horizontal scanning lines per field were not recorded by the conventional apparatus. However, according to the present embodiment, as described above, 24 horizontal scanning lines can be further recorded per field, and therefore, when a high definition image signal is reproduced by the still video device, a missing portion of the screen is generated. It can be reduced significantly compared with the conventional device.

FIG. 8 is a block diagram of a reproduction system of the still video device. The system control circuit 10, the magnetic head 11, the spindle motor 12, and the operation unit 14 are shown in FIG.
Is also included in the recording system shown in (1), that is, they both serve as a recording system and a reproducing system.

The magnetic head 11 is located on a predetermined track of the magnetic disk D and reproduces the ID code and the image signal recorded on this track. The reproduction amplifier 41 reads the image signal and the ID code recorded on the magnetic disk D, and outputs the Y reproduction processing circuit 42, the C reproduction processing circuit 43, and the I reproduction processing circuit 43.
It is output to the D reproduction processing circuit 44. The Y reproduction processing circuit 42 FM demodulates and outputs the luminance signal (Y + S) including the synchronization signal. The C reproduction processing circuit 43 controls the color difference signals (R-Y, B).
-Y) is FM demodulated and output. ID reproduction processing circuit 44
Outputs the ID code after DPSK demodulation.

Sync signal S included in the luminance signal (Y + S)
Is a luminance signal (Y + S) by the synchronization signal separation circuit 45.
And is sent to the memory control circuit 46 and the system control circuit 10. Based on the synchronization signal S, the memory control circuit 46 uses the AD converter 4
7, 48, Y memory 51 and C memory 52 are controlled. Further, the memory control circuit 46, based on a synchronizing signal from a synchronizing signal generating circuit 53 described later, DA converters 54, 55, 56, a Y memory 51 and a C memory 52.
To control.

The luminance signal (Y + S) including the synchronization signal is A
The luminance signal Y which is AD-converted by the D converter 47 and recorded between the two horizontal synchronizing signals is stored in the Y memory 51 under the control of the memory control circuit 46. The brightness signal Y stored in the Y memory 51 is DA-converted by the DA converter 54 based on the synchronization signal (high-speed reference clock signal according to the HDTV system) output from the synchronization signal generation circuit 53. Similarly, color difference signals (RY, B-
Y) is AD-converted by the AD converter 48 and the C memory 5
Stored in 2. The color difference signals (RY, BY) are alternately output from the C memory 52 based on the high-speed reference clock signal, but the color difference signals (RY, BY) of the same horizontal scanning line.
Y) is simultaneously output from the synchronization circuit 57 by the action of the memory control circuit 46 and is input to the DA converters 55 and 56, respectively, and DA converted.

The high speed reference clock signal is stored in the memories 51, 5
2 has twice the frequency of the reference clock signal used for recording the image signal. Therefore, the image signal is read out from each of the memories 51 and 52 at a relatively high speed, whereby the time axis compression is performed.

Blanking sync mix circuits 61 and 6
Reference numerals 2 and 63 are provided to set a predetermined portion in front of each luminance signal (Y + S) and two color difference signals (RY, BY) to a signal of 0 level and to superimpose a synchronization signal. This blanking sync mix circuit 61, 6
2, 63, a clean sync signal conforming to the HDTV system is added in front of these signals. The signals (Y + S), (RY), and (BY) from the blanking sync mix circuits 61, 62, and 63 are output to a display device (not shown).

The interpolation processing circuit 64 calculates the luminance and color difference of the reproduced pixel by interpolation from the luminance and color difference of pixels located around the pixel to be reproduced. This interpolation processing will be described with reference to FIG. Pixels obtained by this interpolation are pixels thinned out at the time of sampling (pixels of code A surrounded by broken lines in the image signal shown by code L).
Corresponding to. Therefore, by averaging the values of the pixels (pixels denoted by reference numerals 33, 35, 24, and 44) located around this pixel (A), this pixel (A)
Gives the value of. Now, the pixels (33, 35) located on the left and right of the pixel (A) are pixels on the same horizontal scanning line,
Pixels (24, 44) located above and below the pixel (A) are pixels located above and below the horizontal scanning line. That is, the pixel (24, 44) is included in a field different from that of the pixel (33, 35). In this way, the thinned pixels are restored by interpolation, and therefore, when the image signal recorded on the magnetic disk is reproduced, an image can be obtained with substantially the same resolution as the input image signal.

The ID code stored in the magnetic disk D is subjected to processing such as DPSK demodulation in the ID reproduction processing circuit 44 and decoded by the system control circuit 10.

FIG. 9 shows a flow chart of a program for reproducing the magnetic disk D recorded by dividing the image signal with respect to the screen and expanding the time axis.

In step 201, the reproduction screen number, that is, the number of the screen to be reproduced is input from the operation unit 14. In step 202, the magnetic head 11 is positioned on the first track, that is, the outermost track of the magnetic disk D, and in step 203, the counter N is "1".
Is set to.

In step 204, the ID of the first track
The code is deciphered. In step 205, this track is set in step 201 based on the content of this ID code.
It is determined whether or not it corresponds to the desired image selected in. If this track does not correspond to the desired image, in step 206 the magnetic head 11
Is moved to the inner side by one track. Then, until the track of the desired image is found, step 204,
205 is repeatedly executed.

[0049] finds a track that contains the desired image, moves from step 205 to step 211, the memory clock is set to a frequency f _'SL. This frequency f ′ _SL is approximately one half of the band f _H of the input image signal (see FIG. 4). Next, at step 212, based on the memory clock of the frequency f _'SL, image signals are AD converted, Y
It is written in a predetermined area of the memory 51 and the C memory 52.

At the time of decoding the ID code, the system control circuit 10 recognizes that the image signal is recorded in the portion corresponding to the vertical blanking period of the normal recording system, and the memory control circuit indicates to that effect. Command. Based on this command, the memory control circuit
AD conversion by AD converters 47 and 48, and memory 5
The write operation to 1, 52 is started earlier than the normal track reproduction, and the image signal recorded within the vertical blanking period is surely stored in the memory.

The image signals of the first and third areas are stored in the memory 5
The image signals of the first and the second regions are written in the odd columns of 1, 52, and the image signals of the second and fourth regions are written in the even columns of the memories 51, 52.
As a result, the arrangement of the image signals on the memories 51 and 52 is shown in FIG.
As shown below, the pixels in the first and third areas are stored in the odd-numbered columns from the left, and the pixels in the second and fourth areas are stored in the even-numbered columns from the left.

In step 213, the difference between the number of memory areas (4 in this embodiment, see FIG. 3) and the counter N is "0".
Is larger than the counter N, and when the number of areas is larger than the counter N, all the image signals are still stored in the memory 51,
Since it is not written in 52, processing for reading the next image signal from the magnetic disk is performed. That is,
At step 214, the counter N is incremented by 1, and at the same time as steps 206, 204, 205,
211 and 212 are executed again, and as described above,
The next image signal is written in the memories 51 and 52.

If it is determined in step 213 that the number of areas is less than or equal to the counter N, the writing of the image signal of one screen into the memories 51 and 52 has been completed.
Steps 221 and below are executed and the image is displayed on the display device. First, in step 221, empty pixels on the memory, that is, thinned pixels,
It is interpolated by the pixels located around it (see FIG. 5). In step 222, the memory clock has frequency f
Set to _SH . This frequency f _SH is twice as high as the frequency f ′ _SH obtained by sub-sampling the input image signal, that is, f
_SH = 2f ' _SH . Next, in step 223, the image signals stored in the memories 51 and 52 are sequentially read and output to the display device or the like.

As described above, in the above embodiment, the still video device can record and reproduce an image of higher quality than the conventional one. Further, when the image signal recorded on the magnetic disk by the conventional still video device is reproduced by the still video device of the above-described embodiment, a plurality of images on one screen are output, and so-called multi-image display is obtained.

Although the image signal is in the frame recording mode in the above embodiment, it goes without saying that the present invention can be applied to the field recording mode.

The present invention can also be applied to the case where an image recorded by the PAL system is recorded on the magnetic disk by the NTSC system. In this case, it is not necessary to divide one screen and record on two tracks, that is, 1
The image signal of the field is recorded on one track. Further, the present invention is capable of converting an image recorded by the HDTV system into a PA.
It is also applicable when recording on a magnetic disk by the L method.

[0057]

As described above, according to the present invention, the HDTV
The image signal recorded by the image signal processing method in which the number of horizontal scanning lines per field is relatively large like the method can be recorded on the recording medium such as the magnetic disk as much as possible. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a recording system of a still video device to which an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a relationship between subsampling of image signals and interpolation.

FIG. 3 is a diagram showing a relationship among an input image signal, an image signal recorded on a memory, and an image signal recorded on a magnetic disk.

FIG. 4 is a flowchart of a program for dividing an input image signal into two, storing them in a memory, subsampling them, and recording them on a magnetic disk.

FIG. 5 is a diagram showing an operation of subsampling an input image signal to record it on a magnetic disk and generating thinned pixels by interpolation.

FIG. 6 is a diagram showing an image signal recorded on a magnetic disk in one embodiment of the present invention.

FIG. 7 is a diagram showing a correspondence relationship between horizontal scanning lines recorded on a magnetic disk and a high-definition horizontal scanning line according to an embodiment of the present invention.

FIG. 8 is a block diagram of a reproduction system of a still video device to which an embodiment of the present invention is applied.

FIG. 9 is a flowchart of a program for reproducing an image signal recorded on a magnetic disk.

FIG. 10 is a diagram showing an image signal recorded on a magnetic disk in a conventional apparatus.

FIG. 11 is a diagram showing a signal waveform of a high-definition system.

FIG. 12 is a diagram showing a correspondence relationship between horizontal scanning lines recorded on a magnetic disk by a conventional device and high-definition horizontal scanning lines.

[Explanation of symbols]

26, 27, 28 memory D magnetic disk (recording medium)

Claims (3)

(57) [Claims] 1. The number of horizontal scanning lines per field is relatively increased by processing an image signal generated by the first image signal processing method in which the number of horizontal scanning lines per field is relatively large. An image signal processing device for generating an image signal according to a small number of second image signal processing methods, wherein the image signal according to the first image signal processing method has a relatively high frequency.
And the second image signal from this memory
Read the image signal at a relatively low frequency according to the processing method
Output and read operation is vertical blanking period of image signal
Start recording during recording the image signal on the recording medium.
Image signal processing apparatus characterized by comprising a that recording means. 2. An image signal according to the first image signal processing method.
Signal is subsampled and stored in memory
The image signal processing apparatus according to claim 1, characterized in. 3. The recording means extends the image signal on a time axis.
2. The information is recorded on the recording medium by means of a recording medium.
Image signal processing device.