JPH0595530A - Video signal reproducing device - Google Patents

Abstract

PURPOSE:To prevent the deviation of noise reduction effect among channels and to minimize a circuit scale by providing only one channel on a motion detection circuit or the like. CONSTITUTION:Adders 62A and 62B subtracts the TCI signal of each channel of the former frame stored in a frame memory 41 from the TCI signal of each channel from a TBC 38. A motion detection circuit 63 detects the motion of the channel B based on a difference between frames from the adder 62B. A coefficient control circuit 64 controls a coefficient K in the noise reduction according to the move. Multipliers 65A and 65B multiplies the coefficient K to the difference between frames of each channel from the adders 62A and 62B. The adders 66A and 66B subtract each multiplication result from the TCI signal of each channel from the TBC 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal reproducing apparatus, and more particularly to a video signal reproducing apparatus for reproducing a video signal by reducing noise of the video signal by utilizing correlation between frames of the video signal.

[0002]

2. Description of the Related Art As a video signal reproducing apparatus for reproducing a video signal recorded on a recording medium, a video tape recorder (hereinafter referred to as VTR) using a magnetic tape as a recording medium is widely known. In such a video signal reproducing device such as a VTR, in order to reduce noise of the video signal,
So-called noise reduction device (hereinafter referred to as NR: Noise Reducer)
Is widely used.

NR is for reducing noise by utilizing the correlation of images in fields and frames, and for example, motion is detected based on a difference between frames of a video signal and this motion is detected from the video signal. The noise component weighted according to the level, for example, the difference between frames is subtracted to remove the noise component included in the video signal, and the so-called S / N (Sign
al to Noise ratio). Then, the S / N improvement degree ρ (dB) of this NR can be obtained by the following Expression 1.

Ρ = 20 log ((1 + K) / (1-K)) ^1/2 (1)

Here, K is a coefficient for weighting the noise component subtracted from the video signal, and is controlled according to the movement so as to have a small value when the movement is large. That is, the closer the coefficient K is to “1”, the greater the S / N improvement degree ρ, but there is an essential characteristic that an afterimage occurs in a moving image. Therefore, the moving image part is detected,
In this moving image portion, although the S / N improvement degree ρ also becomes small, a method is adopted in which the coefficient K is made small to make the afterimage inconspicuous.

By the way, high-definition television (hereinafter referred to as high definition television) is currently under development, and part of it is in the stage of practical application. Further, development of a device for transmitting a high-definition video signal (hereinafter referred to as a high-definition video signal) while maintaining its wide band high quality and a device for recording / reproducing is under way. For example, the luminance signal Y and the color difference signal P _B, P HD video signal supplied as _R, the luminance signal Y and the color difference signal P _B, so-called TCI signal time-base compressed multiplexed to P _R (Time Compressed Integration or TDM signal, Also referred to as)), a device for transmitting and a device for recording / reproducing is actively developed.

Now, the TCI signal will be briefly described. The TCI method is, for example, one horizontal scanning period (hereinafter 1
Luminance signal Y of line) and two color difference signals P _B (B
-Y) and P _R (RY) are time-axis compressed and time-division multiplexed on one line. Specifically, for example, since the color difference signals P _B and P _R have a narrower bandwidth than the luminance signal Y, they are not visually perceived as deterioration of image quality. After axial compression, the color difference signals P _B and P _R are time-compressed to 1/4 times, respectively, and then the color difference signals P _B and P _R are line-sequentially alternated for every other line and time-division multiplexed with the luminance signal Y. To do.

For example, in a video tape recorder (hereinafter simply referred to as a high-definition VTR) which records or reproduces a high-definition video signal using a magnetic tape as a recording medium, the luminance signal Y and the color difference signals P _B and P _R are supplied. The high-definition video signal to be recorded is time-axis compressed and multiplexed as described above and converted into a TCI signal, and this TCI signal is recorded on a magnetic tape, or the recorded high-definition video signal is reproduced as a TCI signal on the magnetic tape. It is like this.

If one field of a wide band signal such as a high-definition video signal is recorded on one slanted track like a general helical scan VTR, the so-called drum diameter is several. It is doubled, and it is difficult to realize a practical high-definition VTR. Therefore, in the high-definition VTR currently under development, one field TCI signal is divided into a plurality of tracks for recording. As a method of dividing, there are so-called segment recording for increasing the rotation speed of a drum and so-called multi-channel recording for simultaneously recording with a plurality of heads, and both of them are used in a high-definition VTR.

Specifically, in a high-definition VTR, for example, the so-called drum rotation speed is doubled and the TC
The I signal is divided into two channels according to the difference of the color difference signals and two heads record simultaneously, that is, two channel recording and four segment recording are used together.

Therefore, also when reproducing, the TCI signals of each channel are simultaneously reproduced by the two heads, and the luminance signal Y and the color difference signals P _B and P _R are separated from the reproduced two-channel TCI signal. The luminance signal Y and the color difference signals P _B and P _R obtained by expanding the time axis are output.

[0012]

By the way, a video signal reproducing apparatus, for example, a high-definition video signal as described above
In a high-definition VTR or the like that reproduces a video signal from a magnetic tape recorded as a CI signal on two channels, for example, when the above noise reduction device (NR) is applied to reduce noise generated during reproduction, NR is the channel Only the number of channels is required, and the characteristic difference between channels becomes a problem.

Specifically, as described above, the NR detects a motion based on a difference between frames and removes a noise component according to the motion. Therefore, in the case of multi-channel recording, it is necessary to detect the motion for each channel and remove the noise component for each channel so that the afterimage and the noise reduction effect are balanced according to the motion. At this time, if the result of the motion detection differs for each channel, the value of the coefficient K differs for each channel, and S
The / N improvement degree ρ differs for each channel. That is, a difference (variation) occurs between the noise reduction effect and the afterimage between adjacent lines. Further, as described above, a circuit for detecting a motion is required for each channel, which causes a problem that the circuit scale increases.

The present invention has been made in view of such circumstances, and is a recording medium in which a video signal of one field or one frame is divided into a plurality of tracks by multi-channel recording and recorded, for example, a high-definition video signal. In a video signal reproducing device such as a high-definition VTR which reproduces a multi-channel recorded magnetic tape using TCI as a TCI signal, it is possible to prevent the noise reduction effect from being different between the channels, and to compare with the conventional device. An object of the present invention is to provide a video signal reproducing device that can reduce the circuit scale.

[0015]

In order to solve the above-mentioned problems, the present invention divides a video signal of 1 field or 1 frame into n tracks and records the video signals for each channel from a recording medium in which n channels are recorded. N reproduction means for reproduction, storage means for storing one frame of output video signal, and each channel of the previous frame stored in the storage means from the video signal of each channel from the n reproduction means N first adding means for subtracting the respective output video signals of the respective channels, and the n first adding means.
Motion detecting means for detecting motion based on the difference between the frames of one channel supplied from one of the adding means, and coefficient control for calculating the noise reduction coefficient K in accordance with the motion from the motion detecting means. Means, n multiplication means for multiplying the difference between the frames of each channel from the n first adding means by the noise reduction coefficient K from the coefficient control means for each channel, and the n multiplication means. And n second adding means for forming the output video signal for each channel by subtracting each output of the n multiplying means from the video signal of each channel from the reproducing means for each channel. Is characterized by.

Further, in the present invention, the video signal of one field or one frame is divided into n tracks, and n pieces of reproducing means for reproducing the video signal for each channel from the recording medium in which n channels are recorded, and one frame are recorded. Storage means for storing the output video signal of each channel, and n for subtracting the output video signal of each channel of the previous frame stored in the storage means for each channel from the video signal of each channel from the n playback means. Number of first adding means, n number of motion detecting means for detecting a motion for each channel based on the difference between the frames of each channel from the n number of first adding means, and the n number of motion detecting means. A coefficient control means for calculating an average value of the movements of the respective channels from the movement detecting means, and a noise reduction coefficient K according to the average value, and the n first additions described above. The difference between the frames of each channel from the stage is multiplied by the noise reduction coefficient K from the coefficient control means for each channel, and n number of multiplication means, and the video signal of each channel from the n reproduction means is used. The present invention is characterized by including n second adding means for respectively subtracting the outputs of the n multiplying means for each channel and forming an output video signal for each channel.

[0017]

In the video signal reproducing apparatus according to the present invention, the video signal of one field or one frame is divided into n tracks, and the video signal is reproduced for each channel from the recording medium in which n channels are recorded. When reducing the noise of the image using the correlation of the images between the frames, the motion is detected based on the difference between the frames of the video signal of the one channel, and the noise reduction coefficient K according to the motion of the one channel is detected. The noise reduction coefficient K is calculated and the difference between frames of each channel is multiplied for each channel, and the multiplication result of each channel is subtracted from the video signal of each channel, and the result is output.

Further, according to the present invention, the video signal of one field or one frame is divided into n tracks and the video signal is reproduced for each channel from the recording medium in which n channels are recorded, and the noise of the reproduced video signal is reduced. When reducing by using the correlation of images between frames, after detecting the motion of each channel based on the difference between the frames of the video signal of each channel, calculate the average value of these and calculate the average value of this motion. The noise reduction coefficient K according to is calculated, and the noise reduction coefficient K is calculated as the difference between the frames of each channel.
For each channel, subtract the multiplication result for each channel from the video signal for each channel,
Output.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a video signal reproducing apparatus according to the present invention will be described below with reference to the drawings. In this embodiment, a high definition television (so-called high definition: High Definition Tele) is used.
The video signal reproducing device according to the present invention is applied to a video tape recorder for vision (hereinafter referred to as a high-definition VTR), and FIG. 1 is a main part of the first embodiment of the video signal reproducing device according to the present invention. The circuit configuration of
FIG. 2 shows a circuit structure of a recording system of this high-definition VTR), and FIG. 3 shows a circuit structure of a reproducing system.

First, the high-definition VTR will be described. In this high-definition VTR, for example, as shown in FIG. 2, a luminance signal Y and color difference signals P _B (BY) and P _R (RY) in one horizontal scanning period (hereinafter referred to as one line) are time-axis compression multiplexed. (Time Compressed Integration), and after the so-called TCI signal obtained is subjected to modulation suitable for recording, etc., 1
A recording system in which a TCI signal for a frame is divided into a plurality of tracks by the recording heads 18A and 18B and recorded on the magnetic tape 1, and, for example, as shown in FIG.
The luminance signal Y and the color difference signals P _B and P _R are separated from the TCI signal of each channel reproduced from the magnetic tape 1 by A and 31 _B , and the time axis is expanded, and the obtained luminance signal Y and color difference signals P _B and P _B are obtained. _It consists of a playback system that outputs _R.

As shown in FIG. 2, the recording system of the high definition VTR has a luminance signal Y and color difference signals P _B and P _R.
Low pass filters (hereinafter referred to as LPFs) 11 _Y , 11 _B and 11 _R and analog / digital (hereinafter referred to as A / D) converters 12 _Y ,
12 _B and 12 _R , and the luminance signal Y converted into a digital signal from the A / D converter 12 _Y is divided into A channel and B channel for each line and time-axis expanded, and the A / D converter is provided. The color difference signals P _B and P converted into digital signals from 12 _B and 12 _R are divided into A channel and B channel for each signal and time-axis compressed, and the obtained luminance signal Y and color difference signals P _B and P _R are obtained. A TCI encoder 20 that forms a TCI signal by time-division multiplexing for each channel, and a digital / analog (hereinafter referred to as D / A) converter 13A that converts the TCI signal of each channel from the TCI encoder 20 into an analog signal. ,
13B and LPF 14A, 14B, and the LPF 14A,
The emphasis circuits 15A and 15B for applying so-called emphasis suitable for recording to the TCI signal of each channel converted to the analog signal from 14B, and the TCI signal of each emphasized channel from the emphasis circuits 15A and 15B, respectively, are so-called. FM modulating FM
Modulators 16A and 16B and the FM modulators 16A and 16B
Recording amplifiers 17A and 17B for amplifying the recording signals of the respective channels obtained by FM modulation from the above and supplying them to the recording heads 18A and 18B, respectively.

Furthermore, the TCI encoder 20, as also shown in FIG. 2, the luminance signal Y from the A / D converter 12 _Y, for example, the odd lines to the A channel, 2 for the even lines and B-channel a change-over switch 21 for dividing the channel, the time axis expander 22A to each time-base-decompressed luminance signal Y of each channel from said changeover switching switch 21, and 22B, the a / D converter 12 _B, 12
Chrominance signals P _B from _R, P _R a with each filter in the vertical direction, for example, the color difference signals P odd lines
_The vertical direction filter 23 that divides _B into the A channel and the color difference signal P _R of the even line into the B channel and the color difference signals P _B and P _R of the respective channels from the vertical direction filter 23 are plotted on the time axis. Time axis compressors 24A, 24B for compression and the time axis expanders 22A, 2
2B from the time axis expanded luminance signal Y and the time axis compressed color difference signals P from the time axis compressors 24A and 24B.
A frame memory 25 for storing _B and P _R, and a sync signal generation circuit 26 for generating so-called sync signals, burst signals, etc.
And the sync signal from the sync signal generating circuit 26 is added (time division multiplexed) to the TCI signal of each channel read from the frame memory 25 (time division multiplexing).
Adder 27 for supplying to converters 13A and 13B, respectively
It is composed of A and 27B.

Furthermore, the vertical filter 23 is further provided.
Is also shown in FIG.
2 _B, 12 color difference signals from _R P _B, the change-over switch 23a for selecting switching the P _R alternately every other line, 23b
And the output of the changeover switch 23a for two lines (2
A delay device 23c that delays the output of the changeover switch 23b by 1H, an adder 23e that adds the output of the changeover switch 23a and the output of the delay device 23c, and the adder 23e. Output of 1 /
A multiplier 23f for doubling, an adder 23g for adding the output of the multiplier 23f and an output of the delay device 23d, and an output of the adder 23g are multiplied by ½, and the color difference signal is filtered in the vertical direction. P _B is the A channel, and the color difference signal P
_{With R} as the B channel, the time axis compressors 24A, 2
4B and multipliers 23h respectively supplied to 4B.

In this recording system, for example, the luminance signal Y supplied via the terminals 2 _Y , 2 _B , and 2 _R is time-axially expanded to approximately 3/2 times, and the color difference signals P _B and P are obtained. _R
, Respectively, and the obtained color difference signals P _B and P _R are line-sequentially alternated every other line to obtain a luminance signal Y of one odd line and a color difference signal P of one odd line. _B is time-division multiplexed within two horizontal scanning periods to form a channel TCI signal, and the luminance signal Y of one even line and the color difference signal P _R of one even line are time-division multiplexed within two horizontal scanning periods. Then, the B channel TCI signal is formed. That is, the luminance signal Y and the color difference signal P
For example, _B and P _R are time-axis compressed to 3/4 times and 1/4 times, respectively, and the time-axis compressed color difference signals P _B and P _R are
Each line is alternately line-sequentially line-sequentially multiplexed with the luminance signal Y, and the obtained TCI signal is divided into A channel and B channel according to the difference in color difference signals, and one line of the divided TCI signal is divided into two horizontal lines. Signal processing equivalent to that in the scanning period is performed. Then, after adding a synchronizing signal or the like to the TCI signal of each channel, FM modulation is performed, and one frame of the FM-modulated TCI signal of each channel is simultaneously recorded for each channel, so-called multi-channel recording and one field. Minute TCI
The signal is divided into a plurality of tracks and recorded by dividing the signal into a plurality of tracks by so-called segment recording. That is, for example, a TCI signal for one frame is divided into eight tracks by two-channel recording and four-segment recording and recorded.

Specifically, the A / D converter 12 _Y digitally processes the luminance signal Y supplied via the terminal 2 _Y and the LPF 11 _Y which is a prefilter by using a sampling clock of, for example, 44.55 MHz. Converted to signal, A /
The D converters 12 _B and 12 _R supply the color difference signals P _B and P _R supplied via the terminals 2 _B and 2 _R and the pre-filters LPF 11 _B and 11 _R , respectively, for example to 11.375.
It is converted into a digital signal by using a sampling clock of MHz. Then, the luminance signal Y and the color difference signals P _B and P _R converted into these digital signals are supplied to the TCI encoder 20.

Changeover switch 21 of TCI encoder 20
_Divides the luminance signal _Y from the A / D converter 12 _Y into two channels, for example, an odd line into an A channel and an even line into a B channel, and the A channel luminance signal Y into a time axis expander 22A. , B channel luminance signal Y
Is supplied to the time axis expander 22B.

The time axis expanders 22A and 22B are composed of, for example, a so-called FIFO (First In First Out) memory, and the time axis expander 22A is a luminance signal Y of the A channel.
Is stored once, and then read out at a clock of, for example, 29.97 MHz, that is, the time axis is extended to approximately 3/2 times,
Similarly, the time axis expander 22B expands the luminance signal Y of the B channel about 3/2 times. Then, the time-axis expanded luminance signal Y is stored in the frame memory 25.
Supply to.

On the other hand, the vertical filter 23 of the TCI encoder 20 filters the color difference signals P _B and P _R from the A / D converters 12 _B and 12 _{R in the} vertical direction, and, for example, the color difference signals of odd lines. P _B is divided into the A channel, the even line color difference signal P _R is divided into the B channel, and the A channel color difference signal P _B is divided into the time axis compressor 2.
4A, the color difference signal P _R of the B channel is applied to the time axis compressor 2
Supply to 4B.

Specifically, the changeover switch 23a of the vertical direction filter 23 alternately selects and selects the color difference signals P _B and P _R from the A / D converters 12 _B and 12 _R every other line to select the delay device. 23c, the changeover switch 23b,
A / D converter 12 _B, 12 chrominance signals P _B from _R, P _R
Are alternately switched and selected every other line in an order different from that of the changeover switch 23a and supplied to the delay device 23d. As a result, for example, the delay unit 23c, the color difference signals P _R of the color difference signal P _B and odd lines of the even lines lines are sequentially supplied to the delay unit 23d, the color difference signal P _B of the odd lines and even lines The color difference signal P _R is line-sequentially supplied.

The delay device 23c delays the color difference signals P _B and P _R , which are line-sequentially supplied from the changeover switch 23a, by 2H, and the delay device 23d is the color difference signal P _B which is line-sequentially supplied from the changeover switch 23b. the P _R is the 1H delay.

Then, the adder 23e to the multiplier 23h are
After adding the output of the changeover switch 23a and the output of the delay device 23c, the output is multiplied by 1/2, and the output of the delay device 23d is added to the multiplication result, and then by multiplying by 1/2. adding the respective quarter of the signal P 1/2 and two even-numbered lines of the color difference signal P _B adjacent thereto of _B, also two odd lines 1/2 and adjacent to the color difference signals P _R of the even lines 1 for each color difference signal P _R
The color difference signals P _B and P _R are filtered in the vertical direction by adding / 4, that is, by obtaining the weighted average in the vertical direction. Then, the color difference signal P _B of the odd line filtered in the vertical direction is supplied to the time axis compressor 24A as the A channel, and the color difference signal P _{R of the} even line is supplied.
Is supplied to the time axis compressor 24B as the B channel.

The time axis compressors 24A and 24B are, for example, FI.
The time axis compressor 24A is composed of an FO memory and the like.
The color difference signal P _B of the channel is once stored and then read out at a clock of, for example, 29.97 MHz, that is, the time axis compression is performed to approximately 1/2, and the time axis compressor 24 B similarly performs the color difference signal of the B channel. P _R is approximately 1/2 times compressed on the time axis. Then, these time-axis compressed color difference signals P _B and P _R are supplied to the frame memory 25.

The frame memory 25 is used by the time axis expander 22.
After temporarily storing the time-axis expanded luminance signal Y from A and 22B and the time-axis compressed color difference signals P _B and P _R from the time-axis compressors 24A and 24B, for example, 29.97M
Based on the read clock of Hz, the color difference signal P _B of the odd line and the luminance signal Y of the odd line are time-division multiplexed for each line and read as the TCI signal of the A channel, and the color difference signal P _R of the even line and the even line Luminance signal Y of each line is time-division-multiplexed and read as a B channel TCI signal. At this time, for example, the T channel for one field is obtained by the above-described multi-channel recording and segment recording.
The writing order and the reading order are reduced so that the influence caused by recording the CI signal by dividing it into a plurality of tracks is reduced and the influence of so-called dropout of the magnetic tape 1 is not concentrated on one place on the reproduction screen. The shuffling TC is performed by so-called shuffling in the field.
The I signal is supplied to the adders 27A and 27B, respectively.

The adders 27A and 27B add the TCI signal of each channel read from the frame memory 25 to the sync signal from the sync signal generating circuit 26, the burst signal, and each segment in the above-mentioned segment recording, for example, four segments. A segment signal for identifying a segment is added to each, and the TCI signal of each channel to which these synchronization signals and the like are added is supplied to each of the D / A converters 13A and 13B.

As described above, the TCI encoder 20 is
The luminance signal Y converted into a digital signal from the / D converter 12 _Y is line by line, for example, the luminance signal Y of an odd line.
To the A channel, and time-base-decompressed with dividing the luminance signal Y of the even lines in the B channel, also the A / D converter 12 _B, 12 color difference signals are converted into digital signals from _R P _B, the P _R Alternately every other line, for example, the color difference signals P _B of the odd lines are divided into A channels, and the color difference signals P _R of the even lines are divided into B channels, and time-axis compression is performed to obtain the obtained color difference signals P _B and P _R , respectively. The TCI of each channel is time-division multiplexed with the luminance signal Y of the same line.
It is designed to form a signal. Further, a synchronizing signal or the like is added to the TCI signal of each of these channels.

D / A converters 13A, 13B and LPF1
4A and 14B are adders 27 of the TCI encoder 20.
The TCI signals of the respective channels to which the synchronization signals and the like from A and 27B are added are converted into analog signals, and the TCI signals of the respective channels converted into these analog signals are supplied to the emphasis circuits 15A and 15B, respectively. As a result, the emphasis circuits 15A and 15B have
For example, as shown in FIG. 4a, in two horizontal scanning periods (2H), the synchronization signal SYNC and the burst signal B are sequentially arranged from the beginning.
S, segment signal SEG, color difference signal C (P _B or P
_R ), and a TCI signal in which the luminance signal Y is time-division multiplexed.

The emphasis circuits 15A and 15B are LP
The TCI signals of the respective channels converted into the analog signals from the F14A and 14B are subjected to emphasis suitable for recording and supplied to the FM modulators 16A and 16B. F
The M modulators 16A and 16B FM-modulate the emphasized TCI signals of the respective channels and supply the modulated TCI signals to the recording amplifiers 17A and 17B. Recording amplifier 17A, 17B
Respectively amplifies the recording signal of each channel obtained by FM modulation and supplies it to the recording heads 18A and 18B. The recording heads 18A and 18B have different so-called azimuth angles from each other, and record the recording signals of the respective channels on the magnetic tape 1 at the same time.

By the way, the magnetic tape 1 is servo-controlled so that, for example, its running speed advances by 8 tracks within a time required to record a TCI signal for 1 frame. By simultaneously recording the divided TCI signals of each channel by the recording heads 18A and 18B, one frame of the TCI signal is divided into 8 tracks (2 channels, 4 segments) and recorded. The high-definition VTR has an audio system (not shown) for recording / reproducing audio signals, for example, converts 4-channel analog audio signals into so-called PCM signals, and converts these PCM audio signals into video signals. The same recording heads 18A and 18B record different areas on the same track. In addition, a playback head 31 for recording the recorded PCM audio signal, which will be described later.
Playback is performed by A and 31B, and an audio signal is output.

As a result, the magnetic tape 1 has, for example, the structure shown in FIG.
As shown in, the TCI signal for one frame is divided into eight tracks 70 by two-channel (A channel, B-channel) recording and four-segment (SEG1 to SEG4) recording, and each track 70 is recorded. , PC
An audio area 71 in which an M audio signal and the like are recorded, and a video preamble area 72 in which a segment sync signal V ₁ and a clamp signal as a reference level of a video signal are recorded.
And a video area 73 in which the TCI signal is recorded are formed.

Next, above as in the luminance signal Y and the color difference signal P _B, the high-definition video signal supplied as P _R, the luminance signal Y and the color difference signal P _B, TCI signal time-base compressed multiplexed to P _R A reproduction system of this high-definition VTR for reproducing a high-definition video signal from the magnetic tape 1 recorded as will be described.

The reproduction system of the high definition VTR is shown in the above figure.
As shown in FIG. 3, from the magnetic tape 1 to the A channel
Playback head that plays back each playback signal of B channel
From the playback heads 31A and 31B and the playback heads 31A and 31B.
Playback amplifier that amplifies the playback signal of each channel of
From the playback amplifiers 32A and 32B and the playback amplifiers 32A and 32B.
Equalize the amplified signal of each channel of
Equalizer (hereinafter referred to as EQ: Equalizer) 33A, 33
B and each equalized channel from the EQ 33A, 33B
Each channel's playback signal is FM demodulated and
FM demodulators 34A and 34B for reproducing a TCI signal, and
TCI of each channel from the FM demodulators 34A and 34B
De-emphasis to de-emphasis each signal
Circuits 35A and 35B and the de-emphasis circuit 35
Channels supplied as analog signals from A and 35B
Convert each channel TCI signal into a digital signal
LPF 36A, 36B and A / D converter 37A, 37B
And digital signals from the A / D converters 37A and 37B.
Correction of the TCI signal of each channel
A so-called time base correction circuit (hereinafter TBC: TimeBase corre
ctor) 38 and the above de-emphasis circuit 35
Synchronous signal from TCI signal of each channel from A and 35B
Signal is detected, synchronization is pulled in, and the A / D conversion is performed.
Supply the reproduction clock to the devices 37A, 37B, TBC38, etc.
Synchronization detection circuit 39 and a time axis from the TBC 38
Reduce noise in the corrected TCI signal of each channel
Together with the TCI signal, the luminance signal Y and the color difference signal P_B, P
_RAnd the luminance signal Y is time-axis compressed to obtain a color difference signal.
P_B, P_RAlong the time axis and one line for recording
Color-difference signals P that are alternately line-sequential_B, P_RTo
By performing line interpolation, color difference signals P for all lines_B, P
_RBroadcast technology development discussion with TCI decoder 40 that reproduces
The so-called three-valued synchronization signal conforming to the BTA studio standard
Signal generating circuit 51 for generating a signal
The ternary sync signal from the signal generation circuit 51 is transferred to the TCI deco
Luminance signal Y and color difference signal P reproduced by the radar 40_B, P_R
To add to each_Y, 52_B, 52_RWhen,
The adder 52_Y, 52_B, 52_R3 value sync signal from
Added luminance signal Y and color difference signal P_B, P_REach
D / A converter 53 for converting into an analog signal and outputting it_Y,
53_B, 53_RAnd LPF54 _Y, 54_B, 54_RAnd
It is composed of

Further, as shown in FIG. 3, the TCI decoder 40 further includes a frame memory 41 for temporarily storing the TCI signal of each channel from the TBC 38 for deshuffling and the like, and the frame memory 41.
The noise reduction device 60 for reducing the noise of the TCI signal of each channel stored on the basis of, for example, the correlation between frames, and the luminance signal Y of each channel read from the frame memory 41 are time-axis compressed. Time axis compressors 42A, 42B and time axis compressors 42B to B
A delay unit 43 for delaying the luminance signal Y of even lines supplied as a channel by 1H, and the time axis compressor 42A
From the A-channel to the odd-numbered luminance signal Y and the delay unit 43 to switch the even-numbered luminance signal Y delayed by 1H for each line and select it as the 1-channel luminance signal Y to the adder 52 _Y. The changeover switch 44 for supplying, the time axis expanders 45A and 45B for expanding the color difference signals P _B and P _R of the respective channels read from the frame memory 41 on the time axis, and the B channel from the time axis expander 45B. Is delayed by 1H by the delay unit 46 for delaying the even-line color difference signal P _R by 1H and the odd-line color difference signal P _B supplied as the A channel from the time axis expander 45A by the delay unit 43. The color difference signals P _R of the even-numbered lines are switched and selected for each line, and the color difference signals P _B and P _{R of} one channel are line-sequential.
And the color-difference signals P _B and P _R alternately line-sequentially supplied every other line from the change-over switch 47 are interpolated to obtain the color-difference signals P _B and P _R of all lines. And an interpolator 48 which supplies the color difference signals P _B and P _R to the adders 52 _B and 52 _R , respectively.

Further, the interpolation circuit 48 outputs the output of the changeover switch 47 to 1 as shown in FIG.
A delay device 48a for delaying H, a delay device 48b for delaying the output of the changeover switch 47 by 2H, and a delay device 48b.
48c for adding the output of the selector switch 47 and the output of the changeover switch 47, a multiplier 48d for halving the output of the adder 48c, and the output of the multiplier 48d and the output of the delay device 48a for each line. Select switch 48
e and 48f.

The reproducing system of the high-definition VTR FM demodulates the reproduced signals of the A channel and the B channel reproduced from the magnetic tape 1 by the reproducing heads 31A and 31B, respectively, and obtains the TCI of each channel.
Signal noise is reduced in the state of the TCI signal, and the luminance signal Y and the color difference signal (P _B or P _R ) for one line are time-axis compression multiplexed within two horizontal scanning periods as shown in FIG. 4a. The luminance signal Y and the color difference signals P _B and P _R are separated from the generated TCI signal, and the luminance signal Y is time-compressed to approximately 2/3 times, and the color difference signals P _B and P _R are approximately doubled. It is designed to extend the time axis. When recording, the color difference signal P _B of the even line which is not reproduced and the color difference signal P _R of the odd line which are not reproduced because the recording is performed line by line alternately every other line, the color difference signal P of the odd line which is reproduced. _B is formed by interpolating the color difference signals P _R of even lines, and the color difference signals P _B , P _R and the luminance signal Y of all the lines obtained are output via the terminals 3 _B , 3 _R , 3 _Y , respectively. It has become.

Specifically, the reproducing heads 31A and 31B
Reproduces the reproduction signal from the magnetic tape 1 for each channel and supplies the reproduction signals of the A channel and the B channel to the reproduction amplifiers 32A and 32B, respectively. Reproduction amplifier 3
2A and 32B amplify the reproduced signals of the respective channels and supply the amplified signals to the EQs 33A and 33B. EQ33A, 3
The 3B equalizes the amplified reproduced signals of the respective channels and supplies the equalized signals to the FM demodulators 34A and 34B. The FM demodulators 34A and 34B perform FM demodulation on the equalized reproduction signals of the respective channels to reproduce the TCI signals of the respective channels. Then, the de-emphasis circuit 35A,
The 35B deemphasizes these TCI signals and supplies them to the LPFs 36A and 36B.

LPFs 36A, 36B and A / D converter 3
7A and 37B are de-emphasis circuits 35A and 35B
TC of each channel supplied as an analog signal from
Each of the I signals is converted into a digital signal, and these T
The CI signal is supplied to the TBC 38. The TBC 38 supplies the TCI decoder 40 with the time-axis corrected TCI signal of each channel that suppresses temporal fluctuations of the TCI signal, such as jitter, that occur during reproduction.

Noise reduction device 60 of TCI decoder 40
Reduces the noise of the TCI signal of each channel from the TBC 38 in the state of the TCI signal.

Specifically, the noise reduction device 60 is composed of, for example, a so-called motion adaptive noise reduction device, etc., and is adapted to reduce noise by utilizing the correlation between frames. For example, FIG. As shown (the same circuits as those shown in the other figures are designated by the same reference numerals), the reproduction of one channel, for example, supplied from the EQ33B shown in FIG. A dropout detection circuit 61 for detecting the dropout of the magnetic tape 1 based on the envelope of the signal, and a TCI signal supplied from the TBC 38 for each channel to the TCI signal of the previous frame stored in the frame memory 41. The difference between the adders 62A and 62B for subtracting each channel and the frame of one channel, for example, the difference between the frames from the adder 62B and A motion detection circuit 63 that detects a motion based on a dropout detection result from the dropout detection circuit 61, and a noise component, for example, for weighting a difference between frames according to the motion from the motion detection circuit 63. A coefficient control circuit 64 for generating a coefficient K, and multipliers 65A, 65B for multiplying the difference between the frames of the respective channels from the adders 62A, 62B by the coefficient K from the coefficient control circuit 64, respectively. The outputs of the multipliers 65A and 65B are subtracted for each channel from the TCI signal of each channel from the TBC 38, and the subtraction results are obtained in the frame memory 41.
To the adders 66A and 66B.

This noise reduction device 60 is
TC of each channel supplied from 38 to each channel
From the I signal, the TCI of the previous frame of each channel stored in the frame memories 41A and 41B for each channel
The respective signals are subtracted, and the difference between the frames of, for example, the B channel of one of these, the dropout detection result of the B channel from the dropout detection circuit 61, and the video signal from the synchronization signal generation circuit 39, for example. The movement of the B channel is detected based on the timing clock indicating the period, and the coefficient K corresponding to this movement is generated. Then, the difference (noise component) between frames of each channel is multiplied by the coefficient K, and the multiplication result is T
The noise of the TCI signal is reduced by subtracting it from the TCI signal of each channel from the BC 38 for each channel.

Specifically, the synchronizing signal generating circuit 39 is
Is also the TCI supplied from the de-emphasis circuits 35A and 35B for each channel as shown in FIG.
A sync separation circuit 39a that detects a sync signal from the signal and pulls in synchronization, and a so-called PLL (Phase Lo) that generates a reproduction clock that is synchronized with the sync signal from the sync separation circuit 39a.
cked Loop) circuit 39b and a timing generation circuit 39c for generating a timing clock indicating, for example, a video signal period based on the reproduction clock from the PLL circuit 39b.
The synchronizing signal generating circuit 39 supplies the reproduction clock to the A / D converters 37A and 37B and the timing clock to the motion detecting circuit 63. Specifically, the timing generation circuit 39c is
For example, as shown in FIG. 4B, a timing clock that is at a high level in the video signal period corresponding to the period of the luminance signal Y and the color difference signal C in the TCI signal is supplied to the motion detection circuit 63.

The motion detection circuit 63 determines that the difference between the frames of the B channel from the adder 62B is valid during the period when the timing clock from the timing generation circuit 39c is at the high level, and the difference between the frames in this valid period is determined as Based on this, for example, when the difference is large, the motion is also large, and the motion of the B channel is detected, and this motion is supplied to the coefficient control circuit 64. Further, at this time, the motion detection circuit 63, based on the dropout detection result from the dropout detection circuit 61, has an unreliable value between the frames when the dropout occurs, For example, the movement in the state before the dropout is detected is supplied to the coefficient control circuit 64. And
The coefficient control circuit 64 generates a coefficient K for noise reduction according to this movement, and the coefficient K is multiplied by the multipliers 65A and 65B.
Supply to. As the above-mentioned timing clock, for example, as shown in FIG. 4c, the period of the luminance signal Y in the TCI signal may be a valid period, and the clock may be a high level during this valid period.

Then, the multipliers 65A and 65B respectively multiply the difference K between the frames of the respective channels from the adders 62A and 62B by the coefficient K obtained as described above,
These multiplication results are supplied to the adders 66A and 66B, respectively. The adders 66A and 66B subtract these multiplication results from the TCI signals of the respective channels from the TBC 38 to reduce the noise of the TCI signals of the respective channels, and the TCI signals with the reduced noise are stored in the frame memory 41.
Supply to.

As described above, when the noise is reduced by adapting to the movement, the noise is reduced in accordance with the movement of one channel, for example, the B channel as described above, and therefore the noise is reduced as in the conventional apparatus. In addition, the detected motion does not vary from channel to channel and the noise reduction effect does not vary from channel to channel. That is, it is possible to prevent a difference (variation) in the noise reduction effect between channels. Also, the circuit for motion detection such as the dropout detection circuit 61 and the motion detection circuit 63 can be provided in only one channel, and the circuit scale can be made smaller than that of the conventional device. Further, since the motion detection is performed in the video signal period or the luminance signal period, the detection accuracy is high. Furthermore, since the motion detection is disabled when dropout occurs, it is possible to prevent erroneous excessive noise reduction during the dropout period.

As described above, the noise-reduced TCI signal in the TCI signal state is deshuffled, separated into the luminance signal Y and the color difference signals P _B and P _R , and read from the frame memory 41. The luminance signal Y is supplied to the time axis compressors 42A and 42B for each channel, and the color difference signals P _B and P _R are supplied to the time axis expanders 45A and 45B for each channel (for each signal).

The time-base compressors 42A and 42B have the luminance signal Y of each channel read from the frame memory 41.
And the delay unit 43 delays the time-axis-compressed luminance signal Y of the B channel, that is, the even-numbered line from the time-axis compressor 42B by 1H.

Then, the change-over switch 44 switches and selects the luminance signal Y of the A channel from the time axis compressor 42A, that is, the odd-numbered luminance signal Y and the even-numbered luminance signal Y delayed by 1H by the delay unit 43 for each line. The luminance signal Y of one channel is supplied to the adder 52 _Y.

On the other hand, the time-axis expanders 45 A and 45 _B respectively time-expand the color difference signals P _B and P _R of the respective channels read from the frame memory 41, and the delay unit 46.
Delays the color-difference signal P _R of the time-axis expanded B channel, that is, the even-numbered line, from the time-axis expander 45B by 1H.

The changeover switch 47 switches the color difference signal P _B of the A channel from the time axis expander 45 A, that is, the odd line color difference signal P _B and the even line color difference signal P _R delayed by 1 H by the delay unit 43 for each line. The color difference signals P _B and P _R of one channel and line sequential are selected and the interpolation circuit 4 is selected.
Supply to 8.

The interpolation circuit 48 line-interpolates the color difference signals P _B and P _R supplied line-sequentially from the changeover switch 47 to form color difference signals P _B and P _R for all lines, and these color difference signals P _B and P _R are formed. _B and P _R are supplied to the adders 52 _B and 52 _R separately for each signal.

Specifically, the delay unit 48 of the interpolation circuit 48
a and 48b delay the color difference signals P _B and P _R, which are line-sequentially supplied from the changeover switch 47, by 1H and 2H, respectively.

Then, the adder 48c to the changeover switch 48
e and 48f are the output of the delay device 48b and the changeover switch 47.
Output is added and then multiplied by ½, and the multiplication result and the output of the delay device 48a are alternately switched and selected for each line, so that, for example, line-sequentially alternate every other line during recording. For this purpose, the color difference signal P _B of the even line which is not directly reproduced from the magnetic tape 1 is formed by interpolation for obtaining the average value of two adjacent color difference signals P _B of the odd lines which are reproduced, and the odd color which is not reproduced. The color difference signal P _R of the line is converted into the color difference signal P _{R of the} even line to be reproduced.
Of the two adjacent ones are formed by interpolation. Then, the color difference signals P _B and P of all the obtained lines are obtained.
_R is supplied to each of the adders 52 _B and 52 _R for each signal.

The adders 52 _Y , 52 _B and 52 _R are
The luminance signal Y and the color difference signals P _B and P _R from the decoder 40 are added with the ternary synchronizing signal from the ternary synchronizing signal generating circuit 51 and supplied to the D / A converters 53 _Y , 53 _B and 53 _R. .. D / A converters 53 _Y , 53 _B , 53 _R and LPF
54 _Y , 54 _B , and 54 _R are the luminance signal Y to which these three-valued synchronization signals are added and the color difference signals P _B and P _R , respectively, converted into analog signals, and the luminance signal Y converted into these analog signals. And the color difference signals P _B and P _R are output to, for example, a monitor receiver via terminals 3 _Y , 3 _B and 3 _R , respectively.

As described above, in the video signal reproducing apparatus according to the first embodiment, the luminance signal Y and the color difference signals P _B and P _R are set to T.
The TCI signal is reproduced for each channel from the magnetic tape 1 in which the video signal of one frame is divided into eight tracks and recorded by converting the CI signal into two channels and four segment recording, and the noise of the reproduced TCI signal is reproduced. Is reduced by utilizing the correlation of images between frames,
Motion is detected based on the difference between the frames of the TCI signal of one channel, a coefficient K corresponding to the motion of this one channel is calculated, and the difference between the frames of each channel is multiplied by this coefficient K for each channel. , By subtracting the multiplication result of each channel from the TCI signal of each channel, it is possible to prevent the noise reduction effect from being different between the channels. Further, the circuit for motion detection, for example, the dropout detection circuit 61, the motion detection circuit 63, etc., may be one channel, and the circuit scale can be reduced as compared with the conventional device.

Next, another embodiment of the video signal reproducing apparatus according to the present invention will be described. FIG. 6 shows a circuit configuration of a main part of a second embodiment of a video signal reproducing apparatus according to the present invention, and this second embodiment also relates to the present invention similarly to the first embodiment. It is assumed that the video signal reproducing apparatus is applied to the reproducing system of the high-definition VTR shown in FIG. 3, and redundant description will be omitted to continue the description.

The video signal reproducing apparatus of the second embodiment also has
Similar to the video signal reproducing apparatus of the first embodiment, when reproducing the magnetic tape 1 in which the TCI signal of one frame is divided into a plurality of tracks by the multi-channel recording and the magnetic tape 1 is reproduced, the coefficient K for noise reduction is set to the A channel. The same is applied to the B channel and the B channel to prevent a difference (variation) in noise reduction effect between the channels.

Specifically, the noise reduction device 80 used in the video signal reproducing device of the second embodiment is, for example, as shown in FIG.
As shown in FIG. 3 (the same circuits as those shown in the other figures are designated by the same reference numerals), the EQ 33 shown in FIG.
Dropout detection circuits 81A and 81B for detecting the dropouts of the magnetic tape 1 for each channel based on the envelopes of the reproduction signals of the respective channels supplied from A and 33B via terminals 87 and 88, respectively, and the above-mentioned T
Adders 82A, 82B for subtracting the TCI signal of the previous frame stored in the frame memory 41 for each channel from the TCI signal of each channel supplied from the BC 38 for each channel, and the adders 82A, 82A
The motion detection circuits 83A and 8 for detecting the motion of each channel based on the difference between the frames of each channel from B and the dropout detection result of each channel from the dropout detection circuits 81A and 81B, respectively.
3B and a coefficient control for calculating an average value of the motions of the respective channels from the motion detection circuits 83A and 83B, and generating a coefficient K for weighting a noise component, for example, a difference between frames according to the average value. Circuit 84 and the adder 82
Multipliers 85A and 85B for multiplying the difference between the frames of the channels from A and 82B by the coefficient K from the coefficient control circuit 84, and the TBC 38, respectively.
From the TCI signal of each channel from
Each of the outputs of A and 85B is subtracted for each channel, and adders 86A and 86B for supplying the subtraction results to the frame memory 41 are provided.

The noise reducing device 80 is
TC of each channel supplied from 38 to each channel
From the I signal, the TCI of the previous frame of each channel stored in the frame memories 41A and 41B for each channel
Subtract the signals respectively, and the difference between these frames,
Based on the dropout detection result of each channel from the dropout detection circuits 81A and 81B, and the timing clock indicating the video signal period or the luminance signal period supplied from the synchronization signal generation circuit 39 shown in FIG. After each motion is detected, the motion of each of these channels is averaged and a coefficient K corresponding to this average value is calculated.
To occur. Then, the noise (noise) of the TCI signal is reduced by multiplying the difference (noise component) between the frames of each channel by a coefficient K and subtracting the multiplication result from the TCI signal of each channel from the TBC 38 for each channel. It is supposed to do.

Specifically, the motion detection circuits 83A and 83B
Is the difference between the frames of the respective channels from the adders 82A and 82B during the period when the timing clock from the synchronization signal generating circuit 39 is at the high level is effective, and based on the difference between the frames in this effective period, For example, when the difference is large, the motion is also large, and the motions of the respective channels are detected, and the motions are supplied to the coefficient control circuit 84. Further, at this time, the motion detection circuits 83A and 83B are the dropout detection circuit 81A and the dropout detection circuit 81A.
Based on the dropout detection result of each channel from 81B, when the dropout occurs, the difference between the frames becomes an unreliable value. Therefore, for example, the movement in the state before the dropout is detected is The coefficients are supplied to the coefficient control circuit 84. Then, the coefficient control circuit 8
4 calculates an average value of the movements of these channels, generates a coefficient K according to this average value, and supplies this coefficient K to the multipliers 85A and 85B.

Then, the multipliers 85A and 85B respectively multiply the difference K between the frames of the respective channels from the adders 82A and 82B by the coefficient K obtained as described above,
These multiplication results are supplied to the adders 86A and 86B, respectively. The adders 86A and 86B reduce the noise of the TCI signal of each channel by subtracting the multiplication results of these from the TCI signal of each channel from the TBC 38, and reduce the noise of the TCI signal of the frame memory 41.
Supply to.

As described above, in the video signal reproducing apparatus according to the second embodiment, when the noise is reduced by adapting to the motion, the noise is reduced according to the average value of the motion of each channel. Therefore, similarly to the video signal reproducing apparatus of the first embodiment, unlike the conventional apparatus, the detected motion does not vary from channel to channel and the noise reduction effect does not vary from channel to channel. That is, it is possible to prevent a difference (variation) in the noise reduction effect between channels. Further, since the motion detection is performed in the video signal period or the luminance signal period, the detection accuracy is high. Furthermore, since the motion detection is disabled when dropout occurs, it is possible to prevent erroneous excessive noise reduction during the dropout period.

The present invention is not limited to the video signal reproducing apparatus using the motion adaptive noise reducing apparatus of the above-mentioned embodiment, but may be a so-called motion component limiting type noise reducing apparatus or Hadamard transform type noise reducing apparatus. It goes without saying that the present invention can be applied to a video signal reproducing device using the above.

[0072]

As is apparent from the above description, according to the present invention, the video signal of one field or one frame is n.
When a video signal is reproduced for each channel from a recording medium in which tracks are divided into n channels and the noise of the reproduced video signal is reduced by utilizing the correlation of images between frames, the video of one channel is reproduced. Motion is detected based on the difference between the frames of the signal, a noise reduction coefficient K is calculated according to the movement of one channel, and the difference between the frames of each channel is multiplied by the noise reduction coefficient K for each channel. By subtracting the multiplication result of each channel from the video signal of each channel, it is possible to prevent a difference (variation) in the noise reduction effect between the channels. Further, since the motion detecting means only needs one channel, the circuit scale can be made smaller than that of the conventional device.

In addition, a video signal of one field or one frame is divided into n tracks, and the video signal is reproduced for each channel from a recording medium in which n channels are recorded. When reducing by utilizing the correlation of, the motion of each channel is detected based on the difference between the frames of the video signal of each channel, then the average value of these is calculated, and the noise corresponding to the average value of this motion is calculated. By calculating the reduction coefficient K, multiplying the difference between frames of each channel by the noise reduction coefficient K for each channel, and subtracting the multiplication result of each channel from the video signal of each channel,
It is possible to prevent the noise reduction effect from being different between channels.

Further, as described in the embodiment, a high detection accuracy can be obtained by setting the effective period for performing the motion detection to the video signal period or the luminance signal period. Further, by invalidating the motion detection during the dropout period, it is possible to prevent erroneous excessive noise reduction during the dropout period.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a main part of a first embodiment of a video signal reproducing device according to the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a recording system of a high-definition VTR to which the video signal reproducing device according to the present invention is applied.

FIG. 3 is a block diagram showing a circuit configuration of a reproduction system of the high definition VTR.

FIG. 4 is a diagram showing a format of a TCI signal.

FIG. 5 is a diagram showing a tape format of a magnetic tape used in the high definition VTR.

FIG. 6 is a block diagram showing a circuit configuration of a main part of a second embodiment of a video signal reproducing device according to the present invention.

[Explanation of symbols]

 41 ... Frame memory 62A, 62B ... Adder 63 ... Motion detection circuit 64 ... Coefficient control circuit 65A, 65B ... Multiplier 66A, 66B ... Adder 82A, 82B ... Adder 83A, 83B ... Motion detection circuit 84 ... Coefficient control circuit 85A, 85B ... Multiplier 86A, 86B ... Adder

Claims (2)

[Claims] 1. A video signal of one field or one frame is divided into n tracks, and the video signal is reproduced for each channel from a recording medium in which n channels are recorded.
Playback means, storage means for storing output video signals for one frame, output video signals for each channel of the previous frame stored in the storage means from video signals for each channel from the n playback means N to subtract the signal for each channel
Number of first adding means and 1 supplied from one of the n first adding means
From a motion detecting means for detecting a motion based on a difference between channel frames, a coefficient controlling means for calculating a noise reduction coefficient K according to the motion from the motion detecting means, and the n first adding means. N multi-plying means for multiplying the difference between frames of the respective channels by the noise reduction coefficient K from the coefficient control means for each channel, and n from the video signals of the respective channels from the n reproducing means. And n second adding means for respectively subtracting the respective outputs of the multiplying means for each channel to form the output video signal for each channel. 2. A video signal of one field or one frame is divided into n tracks, and the video signal is reproduced for each channel from a recording medium in which n channels are recorded.
Playback means, storage means for storing output video signals for one frame, output video signals for each channel of the previous frame stored in the storage means from video signals for each channel from the n playback means N to subtract the signal for each channel
Number of first adding means, n number of motion detecting means for detecting the motion for each channel based on the difference between the frames of each channel from the n number of first adding means, and the n number of motion detecting means. Between the coefficient control means for calculating the average value of the motion of each channel from the motion detecting means and the noise reduction coefficient K according to the average value, and the frame of each channel from the n first adding means. Output of the n multiplication means from the n number of multiplication means for multiplying the noise reduction coefficient K from the coefficient control means for each channel, and the video signal of each channel from the n reproduction means. Is added for each channel to form an output video signal for each channel by n number of second adding means.