JPH06197376A - Video signal recording device - Google Patents

Abstract

PURPOSE:To obtain a maximum band improvement effect in the still picture recording mode and to reduce the cost without need of addition of a memory for still picture storage. CONSTITUTION:In the video signal recorder using a subsample circuit 27 so as to apply offset subsampling to a chroma signal thereby expanding a frequency band, a changeover switch 25 is thrown to the position of a terminal (b) to be selected in the still picture recording mode and a field memory 24 used for pre-filtering processing is used for a still picture memory and offset subsampling processing is applied to all picture elements of the video signal read from the field memory 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal recording apparatus used for recording a video signal on a recording medium such as a tape or a disk, and more particularly to a color signal (chroma signal) of a color video signal in a low range. The present invention relates to a video signal recording apparatus preferably applied to a VTR (video tape recorder) for converting and recording.

[0002]

2. Description of the Related Art In a general household 8 mm VTR (video tape recorder), 1/2 inch VTR, etc., a chroma signal (color signal) component of a color video signal is converted into a low frequency band, and an FM modulated luminance signal component. It is recorded on the magnetic tape together with. The center frequency of the low-frequency conversion chroma signal at this time is set to about 600 to 750 kHz, and the bandwidth is a relatively narrow band of about ± several hundred kHz.

In a video signal recording apparatus for converting a chroma signal into a low frequency band for recording in this way, the chroma signal component of the reproduced signal is a luminance signal component because the bandwidth of the low frequency conversion chroma signal is relatively narrow. Will be inferior to.
In particular, when revising the standard for improving the picture quality of actual home-use VTRs, emphasis has been placed on expanding the frequency band of the luminance signal. In particular, it is necessary to improve the characteristics such as expanding the frequency band.

By the way, it is considered that the chroma signal is sub-sampled or sub-Nyquist sampled in order to substantially expand the frequency band of the chroma signal without changing the recording band on the recording medium such as a tape. There is. This sub-sampling is performed by adding an offset in the time axis direction such as a field offset or a frame offset, or a line offset or the like.
Sampling is performed by adding an offset on the dimensional plane.

Here, when subsampling with an offset in the time axis direction such as the field offset and the frame offset is performed, the characteristics of a so-called moving image in which a screen image moves are deteriorated. It is necessary to perform motion detection and adaptively control the processing amount of subsampling with the offset in the time axis direction according to the detected motion amount.

[0006]

By the way, in the case of adaptively performing sub-sampling having an offset in the time axis direction in accordance with such a motion detection result, a so-called snapshot recording mode or the like is used. In the continuous image recording mode, the processing amount of the sub-sampling may not always be the maximum, and the band expansion effect may not be maximized.

Further, although a field memory is required for moving image processing for performing moving image processing such that sub-sample transmission approaches normal transmission according to the detected motion amount,
Another field memory is required for still image continuous recording. Further, a delay element and a memory are required for continuous recording of field still images and continuous recording of frame still images.

The present invention has been made in view of the above situation, and can maximize the band expansion effect by subsampling in the still image recording mode.
An object of the present invention is to provide a video signal recording device that requires a small number of memories and delay elements and a small capacity.

[0009]

In order to solve the above-mentioned problems, a video signal recording apparatus according to the present invention is a video signal recording apparatus for performing offset subsampling on a video signal to expand the band. In the image recording mode, one screen of the input video signal is stored in the image memory as still image information, and offset subsampling in the time axis direction is performed on all the pixels of the still image video signal read from the image memory. It is characterized by that. In particular, it is preferable that the chroma signal of the color video signal is subjected to offset subsampling in the time axis direction such as between fields and frames to expand the frequency band of the chroma signal.

Here, it is preferable that the movement of the image of the input video signal is detected and the amount of offset subsampling is adaptively controlled according to the detected movement amount. A memory for pre-filtering prior to the offset subsampling may be used as the image memory in the still image recording mode.

Further, when the still picture is recorded as a field still picture, the field memory for pre-filtering is used and an even field video signal and an odd field video signal are interpolated by interpolation processing using data of adjacent lines. When the offset subsampling is performed or the still image is recorded as a frame still image, two field memories for the pre-filtering are used to obtain the frame still image in which the motion between fields is interpolated. Offset subsampling may be performed.

[0012]

In the still image recording mode, the offset subsampling is performed on all pixels to maximize the processing amount of the offset subsampling, so that the maximum band expansion effect can be obtained. Also, using the memory for pre-filtering, which is unnecessary in the still image recording mode,
Since the still image information is stored and the interpolation processing is performed to create the even / odd field information, it is possible to prevent an increase in the memory capacity and the number of delay elements.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a video signal recording apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of a VTR (video tape recorder) which is an embodiment of a video signal recording apparatus according to the present invention. In FIG. 1, the composite color video signal supplied to the input terminal 11 is sent to a Y / C (luminance / chroma signal) separation circuit 12 and separated into a luminance (Y) signal and a chroma (C) signal. It The luminance (Y) signal separated by the Y / C separation circuit 12 is sent to a luminance recording processing (luminance signal recording processing) circuit 13 to be subjected to various signal processing for recording, and is passed through a delay circuit 14. The timing is adjusted with the chroma signal side and is sent to the adder 15.

The chroma signal separated by the Y / C separation circuit 12 is sent to the color difference decoder 21 and the color difference signals R-Y, B.
After being converted into −Y and sent to the chroma recording processing circuit 22 and subjected to required signal processing, the pre-filter circuit 23 performs filter processing prior to the offset sub-sampling. For the filtering process by the pre-filter circuit 23, a field memory 24 for two fields is used, for example, vertical and temporal filtering is applied. The filtered signal is sent to the selected terminal a of the changeover switch 25, and the signal read from the field memory 24 is sent to the selected terminal b of the changeover switch 25. The changeover switch 25 is switch-controlled according to a still image recording command signal from the terminal 26, for example, a so-called snapshot signal, and is set to the selected terminal a side during normal recording and to the selected terminal b side during still image recording, respectively. Switched and connected.

The output signal from the change-over switch 25 is sent to the sub-sampling circuit 27 and subjected to, for example, field offset sub-sampling. Sub sample circuit 2
The signal from the signal No. 7 is sent to the low frequency conversion circuit 28 to be encoded into the carrier color signal from the color difference signals RY and BY, and the signal having the center frequency of 743 kHz in the case of 8 mm VTR, for example. Is converted to low frequency. The low-pass converted chroma signal is filtered by a filter circuit 29 such as a low-pass filter and sent to the adder 15.

The adder 15 is supplied with an AFM signal (audio FM signal), an ATF signal (pilot signal for tracking control), etc. in addition to the luminance (Y) signal and chroma (C) signal. These signals are added and mixed, amplified by an amplifier 16, sent to a recording head 17 of a rotary head device, and recorded on a video tape 18 in a predetermined format.

In the above construction, in the so-called snapshot recording mode, which is the continuous recording mode of the field still image, the changeover switch 25 is connected to the selected terminal b side for changeover, and for example one field stored in the field memory 24. Image signals of are continuously read and sent to the sub-sampling circuit 27. This allows the field memory 24 already provided for the prefilter.
Since it can also be used for storing the field still image, it is not necessary to separately provide a memory dedicated to storing the field still image, and the configuration can be simplified and the cost can be reduced. In addition,
Of course, it is also possible to store the frame still image using all two fields of the field memory 24.

Here, a more concrete configuration example of a part of the chroma signal system pre-filter 23, the field memory 24, the pre- and post-circuits of the sub-sampling circuit 25, and a part of the luminance signal system, which are essential parts of the present invention, This will be described with reference to 2.

A color difference signal obtained from the color difference decoder 21 via the chroma recording processing circuit 22 is supplied to the input terminal 31 of FIG. This input signal is sent to the series connection circuit of 1 field delay circuits 32 and 33 corresponding to the field memory 24 for the above 2 fields, and the delayed output signal from the 1 field delay circuit 32 is a 1H (horizontal period) delay circuit. 34, 1: 3 interpolation circuit 35, and adder 36. The output signal from the 1H delay circuit 34 is sent to the adder 36, and the output signal from the adder 36 is sent to the selected terminal a of the changeover switch 37. The output signal from the 1: 3 interpolation circuit 35 is sent to the selected terminal b of the changeover switch 37. The output signal from the changeover switch 37 is a prefilter 38 corresponding to the prefilter 23 in FIG.
Have been sent to.

In a normal recording mode other than the still image recording mode such as the so-called snapshot recording described above, the changeover switch 37 is connected to the selected terminal a by changeover, and at this time, the prefilter 38 is Adder 3
An output signal from 6 and an input signal from the input terminal 31,
This input signal has two 1-field delay circuits 32 and 33.
By using the information of 3 fields of the output signal delayed by 2 fields (1 frame) at 1, the spatial filtering process as shown in FIG. 3 for band limitation prior to sub-sampling is performed.

A specific example of this pre-filtering process will be described with reference to FIGS. 3 and 4. In FIG. 3, the horizontal axis represents time t and the vertical axis represents the vertical position v of the field screen, showing pixels used for the pre-filtering. In FIG. 3, a field (previous field) Fb that is one field before on the past side of the time axis with respect to the current time field (current field) Fa.
Is arranged, and the next field Fc is arranged on the future side.
The filtering process for an arbitrary pixel x on the current field Fa is performed by the pixels e and f on the lines above and below the pixel x on the same current field Fa and 1/2 on the previous field Fb.
Pixels a and b above and below the line and 1 / on the next field Fc
This is performed using the pixels c and d above and below two lines. FIG. 4 shows only the portion related to this pre-filter processing, and the comb filter 40 provided on the upstream side of the circuit portion of FIG. 2 is also used. The comb filter 40 does not need to be separately provided, for example, by diverting a filter used for Y / C separation or by using a filter used for chroma crosstalk removal during reproduction also during recording. .

In FIG. 4, the comb filter 40 provided on the upstream side of the circuit section shown in FIG. 2 includes a 1H delay circuit 40a, coefficient multipliers 40b and 40c, and an adder 4.
It consists of 0d. The comb filter 40 averages the pixels above and below the line. Now, assuming that the output from the 1-field delay circuit 32 is the current field, the data of (c + d) / 2 corresponding to the average value of the pixels of c and d in FIG. 262H) It is sent to the delay circuit 32 and the pre-filter 38. This input data is delayed by one field in the one-field delay circuit 32, so that (x + f) / 2, which is the average of the pixels x and f in FIG. 3, is 1H delay circuit 34.
And an adder 36, and from the 1H delay circuit 34, as shown in FIG.
(E + x) / 2 of the average of the pixels e and x of the pixel is sent to the adder 36, and the output from the adder 36 is (e + 2x + f)
It becomes / 2 and is sent to the pre-filter 38. Further, the 1-field (263H) delay circuit 33 outputs a 2-field (1-frame) delayed output of the input data shown in FIG.
The average (a + b) / 2 of the pixels a and b of is extracted and sent to the pre-filter 38. In the pre-filter 38, these three inputs are multiplied by 1 in each of the coefficient multipliers 38a, 38b, and 38c, and added by the adder 38d to obtain (a + b) / 8 + (e + 2x + f) / 8 + (c + d). The calculation of / 8 = a / 8 + b / 8 + e / 8 + x / 4 + f / 8 + c / 8 + d / 8 is performed.

This pre-filtering process uses a low-pass filter in the time axis direction in order to prevent an error that occurs when sub-sampling having an offset in the time axis direction (for example, field offset) is performed on a moving image. It is a process that is applied. This pre-filtering process is not necessary when, for example, field offset sub-sampling is performed on a still image having no motion.

Returning to FIG. 2 again, the output signal subjected to the pre-filtering processing as described above is sent to the sub-sampling circuit 39 corresponding to the sub-sampling circuit 27 in FIG. Is applied. The output signal from the sub-sampling circuit 39 is multiplied by (1-K) in the variable coefficient multiplier 41, and then added by the adder 43.
Sent to. The signal from the changeover switch 37 before sub-sampling is supplied to the adder 43 by the variable coefficient multiplier 42.
The output signal from the adder 43 is taken out via the terminal 44.

Here, the variable coefficient multipliers 41 and 42 and the adder 43 constitute an adaptive processing unit in which the value of K is controlled according to the amount of movement of the image. That is, the amount (or level) of the signal passing through the path for performing field offset sub-sampling is determined by the coefficient (1
-K), and the amount (or level) of the signal through the through path that does not perform the sub-sampling is determined by the coefficient K of the variable coefficient multiplier 42, and therefore the coefficient ( 1-K) and K, the ratio between the chroma signal with offset sub-sampling and the chroma signal with no sub-sampling is adaptively controlled. The motion detection for this adaptive processing is performed for both the chroma signal and the luminance signal as described later.

First, the motion detection for the chroma signal is
This is performed by sending the input signal from the input terminal 31 and the signal delayed by one frame by the two 1-field delay circuits 32 and 33 to the chroma (C) motion detection circuit 46 to obtain a so-called inter-frame difference. . The motion detection output from the chroma motion detection circuit 46 is sent to the maximum value detection circuit 47 and compared with the motion detection output from the luminance motion detection circuit 57 described later, and the larger one is taken. The output signal from the maximum value detection circuit 47 is a changeover switch 48.
Is sent as a control signal of K (coefficients K and 1-K) to the variable coefficient multipliers 41 and 42 of the adaptive processing section via the selected terminal a.

Next, the luminance signal system will be briefly described. The input terminal 51 is supplied with the luminance (Y) signal that has been subjected to the Y / C separation and subjected to the necessary processing. This luminance signal is sent to the selected terminal a of the changeover switch 56 via the 1H delay circuit 52, the 1-field delay circuit 53, and the 1H delay circuit 54. The (input / output) signals before and after the 1H delay circuit 54 have a 1: 3 interpolation circuit 55.
The output signal from the 1: 3 interpolation circuit 55 is sent to the selected terminal b of the changeover switch 56. The output signal from the changeover switch 56 is a luminance (Y) motion detection circuit 57.
Sent to.

The output signal from the 1H delay circuit 52 on the input side is sent to the adder 59 through the selected terminal a of the changeover switch 58.
By adding the input signal from 1, the upper and lower lines are averaged. The output signal from the adder 59 is sent to the luminance motion detection circuit 57. Therefore, in the motion detection circuit 57, the data of the current field from the changeover switch 56 and 1 of the next field from the adder 59.
The luminance (Y) is obtained by comparing the average value of the data at the upper and lower positions of the / 2 line and taking the so-called inter-field difference.
Motion detection is performed. The luminance (Y) motion detection output from the motion detection circuit 57 is sent to the maximum value detection circuit 47. As described above, the maximum value detection circuit 47 compares it with the motion detection output of the chroma (C), takes out the larger one, and sends it as a control signal to the variable coefficient multipliers 41 and 42 of the adaptive processing section. On the street.

The luminance signal from the changeover switch 56 is added with synchronization by the synchronization adding circuit 61, and after the delay time is adjusted (timing adjustment) with the chroma system by the delay circuit 62, it is taken out from the terminal 63.

As described above, in the chroma signal system, field offset subsampling is performed, and in consideration of the fact that the field difference cannot be detected on the reproducing side or the receiving side, the motion is detected by calculating the interframe difference. Therefore, in the luminance signal system, motion detection is performed by taking an inter-field difference with a smaller error in the time axis direction. The motion amounts detected by the chroma system and the luminance system are combined by maximum value detection or the like to obtain a control signal for adaptively controlling the ratio of the offset sub-sample. this is,
The probability of erroneous detection increases only by the motion detection based on the difference between chroma frames, while the more accurate motion detection can be performed by taking the difference between the fields of the luminance into consideration. The combination of the chroma motion detection output and the luminance motion detection output is not limited to taking the maximum value described above, and for example, a weighted average may be taken.

By the way, the changeover switches 37, 48,
56 and 58 are switch-connected to the selected terminal a side in the normal recording mode, and in the so-called snapshot recording mode for continuously recording still images (for example, field still images), still image recording from the terminal 45. Switching control is performed to the selected terminal b side according to the control signal. Further, the still image recording control signal from the terminal 45 is sent to the pre-filter 38 to control to stop the pre-filtering operation.

That is, in the continuous recording mode of field still images such as so-called snapshot recording,
The 1-field delay circuit (field memory) 32,
The field video data stored in 53 is continuously and repeatedly read, and the 1H delay circuits 34 and 54 are also read.
Is used to extract the still image signal obtained by performing the interpolation processing by the 1: 3 interpolation circuits 35 and 55 from the respective changeover switches 37 and 56. Further, the operation of the pre-filter 38 is stopped and the changeover switch 48 is switched to the selected terminal b side to control the value of K in each of the multiplication coefficients of the coefficient multipliers 41 and 42 to 0. As a result, on the chroma system side, the interpolated signal from the 1: 3 interpolation circuit 35 is sub-sampled without undergoing the pre-filtering process, and the ratio of the signal passing through the sub-sample path is 1 and the through path is passed. The signal passing through becomes 0 and is taken out from the output terminal 44 via the adder 43. On the luminance system side, the interpolated signal from the 1: 3 interpolation circuit 55 is taken out via the changeover switch 56.

Here, the 1: 3 interpolation circuit 35 (or 55) in FIG. 2 will be described with reference to FIGS.
FIG. 5 is a diagram for explaining the interpolation operation in the 1: 3 interpolation circuit 35 (or 55).
A field (memory field) F _me stored in 2 (or 53) and repeatedly read, and an even field F _{ev of A} and an odd field F _{od of} B obtained by performing an interpolation process on the data of this memory field F _me are shown. ing. That is, in FIG. _5A, for the data D _evN on an arbitrary line (Nth line) of the even field F _ev , the data D _N on the corresponding line (Nth line) of the storage field F _me is set to 3 / 4 times and the next line (Nth +
Data D _{N + 1} on 1 line) and 1/4 times the data D _{N + 1} , and the data D _odN on any line (Nth line) of the odd field F _{od in} FIG. _5B. Is obtained by multiplying the data D _N on the corresponding line (Nth line) of the storage field F _me by 1/4 and the next line (N + th line).
It is obtained by adding the data D _{N + 1} on one line) multiplied by 3/4.

This is because the data in the storage field F _me is directly used in one field (for example, an even field).
This is because when the average value of the upper and lower lines is used for the data of the other field (odd field), it is considered that the image quality varies in the even field and the odd field. By performing the same interpolation processing on both odd fields, the image quality of each field can be made uniform.

FIG. 6 shows the 1: 3 interpolation circuit 35 (or 5).
5) shows a concrete circuit configuration example of 5), and the input terminal 71
Video signals having a shift of 1H (1 line) are respectively supplied to a and 71b by the 1H delay circuit 34 (or 54). The signals from these input terminals 71a and 71b are latched (D flip-flop) 72, respectively.
It is sent to the selected terminals a and b of the changeover switch 73a and the selected terminals a and b of the changeover switch 73b via a and 72b, respectively. The changeover switches 73a and 73b are
Switching (switching and inversion for each field) is controlled in a frame cycle by interlocking with each other in the relationship of connection states opposite to each other.
Specifically, the changeover switch 73b is switch-controlled by a changeover control signal obtained by inverting a frame pulse signal (a signal which is alternately inverted between the even field and the odd field) from the terminal 74a by the inverter 74, and the inverted signal is further inverted. The changeover switch 73a is switch-controlled by a signal inverted by 74c (a signal having the same polarity as the input signal from the terminal 74a). Therefore, for example, the changeover switch 73a is connected to the selected terminal a and the changeover switch 73b is connected to the selected terminal b in the even field, the changeover switch 73a is connected to the selected terminal b and the changeover switch 73b is selected in the odd field. The switching control is performed so as to be connected to each. The output from the changeover switch 73a is sent to the coefficient multiplier 75a and multiplied by a coefficient 3/4, and the output from the changeover switch 73b is multiplied by the coefficient multiplier 75b.
And is multiplied by a factor of 1/4. The outputs from these coefficient multipliers 75a and 75b are latched (D
Adder 77 via flip-flops 76a and 76b
To the latch (D flip-flop) 7
It is taken out via 8.

The changeover switches 66 and 68 shown in FIG.
Signals sent to electronic viewfinders (so-called E to E
Signal), the selected terminal a is selected in the normal recording mode, and the chroma and luminance signals from the input terminals 31 and 51 are output to the output terminals 67 and 69, respectively, and the electronic viewfinder, etc. I am sending it to. In the field still image recording mode described above, the changeover switch 66,
68 is switch-controlled to the selected terminal b side, and the signal interpolated by the 1: 3 interpolation circuits 35 and 55 is selected and sent to the electronic viewfinder or the like via the output terminals 67 and 69.

As described above, in the still image recording mode such as the so-called snapshot recording mode,
The one-field delay circuit (field memory) used in the pre-filtering process and the like is used because the sub-sampling processing amount is maximized to obtain the maximum band expansion effect and the pre-filtering process and the like are not necessary. Field image information for still image recording is stored in 32 or 53 and repeatedly read out to eliminate the need for a dedicated memory for storing still images, thereby reducing the number of parts and reducing the price. Further, since the even and odd fields of the field still image are created by 1: 3 interpolation using the 1H delay circuit 34 used for the prefilter for the operation processing, a new 1: 3 is added.
There is no need to add a 1H memory for interpolation, and since subsampling is performed after that, a so-called E to E signal becomes a beautiful still image.

In the above description, the case of recording as a so-called field still image is illustrated, but it may be recorded as a so-called frame still image. In the case of this frame still image recording, the two field memories 32 used in the pre-filtering,
33, a video signal for one frame (two fields) is stored, the motion between the two fields is interpolated to make a moving image a still image of one frame, and then the offset sub-sampling is performed. . In this case as well, it is of course possible to obtain the maximum band expansion effect and reduce the cost by reducing the memory.

Next, an example of the configuration of the signal reproducing system with respect to the configuration of the signal recording system as described above will be described with reference to FIG. The video tape 18 on which the video signal is recorded by the signal recording system as shown in FIG. 1 is reproduced by the reproducing head 81, amplified by the amplifier 82, and then filtered by the filter 8.
3, 84, the luminance separation filter 85, and the chroma separation filter 86 to send an AFM (audio FM) signal,
The ATF (pilot signal for tracking control), the luminance signal and the chroma signal are separated and taken out. The signal from the brightness separation filter 85 is demodulated by the brightness demodulation circuit 87, subjected to various signal processing for reproduction by the brightness reproduction processing circuit 88, and sent to the adder 89.

The chroma signal from the chroma separation filter 86, which has been low-pass converted to, for example, 743 kHz, is decoded into a color difference signal by the decoder 91, and the chroma reproduction processing circuit 9
2 is processed, then sent to the resample circuit 93,
Interpolation circuit 9 is resampled with the same clock as when recording
Sent to 4. The interpolation circuit 94 uses a field memory to perform an interpolation process using data of at least one field before and after the current field.
Expand the chroma frequency band. The interpolated signal is sent to the encoder 95, converted into a chroma signal having an NTSC subcarrier frequency of 3.58 MHz, and sent to the adder 89. The addition signal from the adder 89 is taken out via the output terminal 90.

Next, FIG. 8 is a frequency characteristic diagram for explaining the effect of expanding the frequency band of the chroma signal when the sub-sampling process is performed on the chroma signal as described above, and is applied to a so-called 8 mm VTR. In this case, the curve a in the figure shows the measured value when the sub-sampling process is performed, and the curve b shows the measured value when the sub-sampling process is not performed. As is clear from FIG. 8, it is possible to realize the expansion of the frequency band that is almost double that of the conventional frequency band, and it is possible to obtain good image quality, especially excellent color reproducibility.

The present invention is not limited to the above-mentioned embodiment, and in the above-mentioned embodiment, a so-called NTSC type 8 mm VTR is described as an example.
TR or VT other than 8 mm, for example, 1/2 inch type
Of course, the present invention can be applied to R and the like. Also,
The present invention can be applied to various video signal recording devices such as a disk recording device other than the VTR. Besides, various modifications can be made without departing from the scope of the present invention.

[0044]

According to the video signal recording apparatus of the present invention, in the still image recording mode, one screen of the input video signal is stored in the image memory as still image information, and the still image read from the image memory is stored. Since the offset sub-sampling in the time axis direction is performed on all the pixels of the image video signal to maximize the processing amount of the offset sub-sampling, the maximum band expansion effect can be obtained.

Further, since the memory for pre-filtering, which is unnecessary in the still image recording mode, is used for storing the still image information and performing the interpolation process for creating the even / odd field information, the memory, the delay element, etc. No need to add.

Furthermore, since the even-numbered and odd-numbered field signals of the field still image are generated by using the 1H delay circuit used for the moving image processing, a new 1H memory is not required and the pre-filter of the pre-filter is used even during the frame still image. Since the memory can be used as a memory for field interpolation to create a still image from a moving image, it is not necessary to add a new memory.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a schematic configuration of an embodiment of a video signal recording device according to the present invention.

FIG. 2 is a block circuit diagram showing a specific example of a main configuration of the embodiment of FIG.

FIG. 3 is a diagram for explaining the operation of pre-filtering processing.

FIG. 4 is a block circuit diagram showing a portion used for pre-filtering processing.

FIG. 5 is a diagram for explaining a 1: 3 interpolation process for creating an even field signal and an odd field signal when recording a field still image.

FIG. 6 is a circuit diagram showing a specific example of a 1: 3 interpolation circuit.

7 is a block circuit diagram showing a specific example of a video signal reproducing device for reproducing a medium recorded by the video signal recording device of the embodiment of FIG.

FIG. 8 is a frequency characteristic diagram showing a frequency band expansion effect when a chroma signal is sub-sampled.

[Explanation of symbols]

 23 ... Pre-filter 24 ... Field memory 25 ... Changeover switch 26 ... Changeover control signal input terminal 27 ... Sub sample circuit 32, 33, 53 ... .... 1 field delay circuit 34, 52 ... 1H (horizontal period) delay circuit 35, 55 ... 1: 3 interpolation circuit 36, 43 ... adder 37, 48, 56, 66, 68 ... Changeover switch 38 ... Pre-filter 39 ... Sub-sampling circuit 41, 42 ... Variable coefficient multiplier 46 ... Chroma motion detection Circuit 47 ... Maximum value detection circuit 57 ... Luminance motion detection circuit

Claims (5)

[Claims] 1. A video signal recording apparatus for expanding a band by performing offset sub-sampling processing on a video signal, wherein one screen of an input video signal is stored in a picture memory as still picture information in a still picture recording mode. A video signal recording apparatus, wherein offset subsampling in a time axis direction is performed on all pixels of a still image video signal read from the image memory. 2. The video according to claim 1, wherein the motion of the image of the input video signal is detected, and the amount of offset sub-sampling is adaptively controlled according to the detected motion amount. Signal recorder. 3. The video signal recording apparatus according to claim 1, wherein a memory for pre-filtering prior to the offset sub-sampling is used as the image memory in the still image recording mode. 4. When recording the still image as a field still image, the field memory for pre-filtering is used to perform interpolation processing using data of adjacent lines to generate an even field video signal and an odd field video signal. The video signal recording apparatus according to claim 3, wherein the offset sub-sampling is performed after the determination. 5. When the still image is recorded as a frame still image, the offset sub-sampling is performed as a frame still image in which motions between fields are interpolated by using two field memories for the pre-filtering. The video signal recording device according to claim 3.