JPH07264627A - Video signal processing circuit - Google Patents

Abstract

PURPOSE:To provide the video signal processing circuit which enables a 1H delay circuit to be used for a camera and a VTR signal processing circuit in comm. CONSTITUTION:This video signal processing circuit 10 is equipped with a CCD image sensor 2a which has a color filter array of a color difference line sequential system, a recording system signal processing circuit 3a and a reproduction system signal processing circuit 3e which record and reproduce a video signal based on the signal outputted from the sensor 2a, and 1H delay circuits 13 and 14 which delay a supplied color difference line sequential signal or reproduced video signal by 1H so as to perform vertical simultaneity in recording and reduce noises of the reproduced video signal in reproduction.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing circuit.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a configuration of a video signal processing circuit of a camera-integrated VTR, FIG. 3 is a diagram showing a color filter array of a color difference line sequential system, and FIG. 4 is a specific configuration of a camera signal processing circuit. FIG. 5 is a diagram showing a configuration of a comb filter for removing crosstalk, FIG. 6 is a diagram showing a configuration of a recursive comb filter, and FIG. 7 is a diagram for explaining an H-correlation noise reduction circuit. .

At present, a video signal processing circuit 1 of a camera-integrated video tape recorder (VTR) is roughly composed of a CCD image sensor 2a, a camera signal processing circuit 2 and a VTR signal processing circuit 3 as shown in FIG. There is. The camera signal processing circuit 2 and the VTR signal processing circuit 3 are respectively configured by using separate circuit elements such as ICs. The camera signal processing circuit 2 described above is a 1H delay circuit 2
b, 2c, and a camera signal processing unit 2d.
Further, the VTR signal processing circuit 3 is a recording system signal processing circuit 3
a 1H delay circuits 3b and 3c, reproduction system signal processing circuit 3d
Recording amplifier, preamplifier (both not shown)
It consists of The above-mentioned 1H delay circuits 2b and 2
Reference characters c, 3b, and 3c are, for example, 1H delay lines that delay and output the input signal for 1H (1 horizontal scanning) period. In this way, the camera signal processing circuit 2 and the VTR signal processing circuit 3 are respectively 1
The H delay circuits 2b and 2c and the 1H delay circuits 3b and 3c are separately provided.

Next, a camera-integrated VTR having the above structure
The recording / reproducing operation of the video signal processing circuit 1 will be described.

(At the time of recording) A CC having a field color difference line-sequential color filter array (shown in FIG. 3 described later)
The original signal (color difference line sequential signal) output from the D image sensor 2a is a 1H delay circuit 2b and a camera signal processing unit 2d.
Are supplied to each. The 1H delay circuit 2b converts this original signal to 1
The 1H delayed signal delayed by H is output to the 1H delay circuit 2c at the next stage. The 1H delay circuit 2c outputs a 2H delay signal obtained by further delaying the input 1H delay signal by 1H to the camera signal processing unit 2d at the next stage. These 3 signals (original signal, 1H and 2H
The delay signal is supplied to a luminance signal system (comb filter 2d1 for noise reduction shown in FIG. 4 described later) and a color signal system (simultaneous circuit 2d2 in FIG. 4) that configure the camera signal processing unit 2d, respectively. . Luminance signal system (comb filter 2d1)
The noise signal is output from the luminance signal. Also, from the color signal system (simultaneous circuit 2d2), the color difference signal (RY),
(BY) is output, and thereafter, a carrier color signal obtained by balanced modulation with a balanced modulator (not shown) is generated. This balanced modulator is provided in the camera signal processing section 2d only when it is desired to output the carrier color signal from here. Needless to say, when it is desired to take out the color difference signals (RY) and (BY) from the color signal system, this balanced modulator need not be provided in the camera signal processing section 2d. In this way, the luminance signal and the carrier color signal (or the luminance signal and the color difference signals (RY) and (BY)) are output from the camera signal processing unit 2d, respectively.

The luminance signal and the carrier color signal output from the camera signal processing circuit 2 (camera signal processing unit 2d) are output to the VTR signal processing circuit 3 (recording system signal processing circuit 3a), respectively, and also via the switch SW. It is output as a monitor output to a viewfinder (not shown) or the like. The luminance signal supplied to the recording system signal processing circuit 3a is subjected to a required recording process in the luminance signal recording processing system and output to the YC mixing circuit as an FM modulation luminance signal. On the other hand, a carrier color signal supplied to the recording system signal processing circuit 3a (or a color difference signal (RY) supplied via a balanced modulator (not shown),
(BY)) is subjected to required recording processing in the color signal recording processing system and is output to the YC mixing circuit as a low-frequency conversion color signal. The YC mixing circuit supplies a frequency-multiplexed signal obtained by frequency-multiplexing the FM-modulated luminance signal and the low-frequency converted color signal to a video head (neither is shown) via a recording amplifier.
In this way, the luminance signal and the carrier color signal output from the camera signal processing circuit 2 are subjected to required recording signal processing in the VTR signal processing circuit 3 and then sequentially recorded on the magnetic tape by the video head.

(At the time of reproduction) The reproduction signal obtained by scanning the signals continuously recorded on the magnetic tape by the video head is output to the VTR signal processing circuit 3 (reproduction system signal processing circuit 3d) through the preamplifier. To be done. Reproduction system signal processing circuit 3d
As is well known, the YC separation circuit separates and outputs the reproduction signal supplied to the FM luminance signal and the low-frequency conversion color signal, and the separated and outputted FM luminance signal is subjected to the required reproduction processing in the luminance signal reproduction processing system. Is output to the YC mixing circuit as a luminance signal (here, the luminance signal is delayed by 1 line for 1H).
A H-correlation noise reduction process (H-correlation noise reduction circuit) 6 shown in FIG. 7, which will be described later, in which the delay circuit 3c is part of the configuration is used to perform H-correlation noise reduction processing to reduce noise). On the other hand, the low-pass converted color signals that have been separately output are subjected to the required reproduction processing in the color signal reproduction processing system and output to the YC mixing circuit as the carrier color signal (here, the carrier color signal is output from the 1H delay circuit 3b). Crosstalk components are removed by the comb filters 4 and 5 shown in FIGS. 5 and 6 which will be described later as a part of the configuration). The YC mixing circuit uses the switch SW as a reproduction composite video signal, which is a frequency-multiplexed signal obtained by frequency-multiplexing the luminance signal and the carrier color signal.
Monitor output via. In this way, the signal recorded on the magnetic tape is reproduced after the VTR signal processing circuit 3 has performed necessary reproduction signal processing.

As shown in FIG. 4, the camera signal processing unit 2d constituting the camera signal processing circuit 2 has a CCD 2a for each comb filter 2d1, 1H for noise reduction of a luminance signal and vertical edge enhancement. A synchronization circuit 2d2 for vertically synchronizing color difference line sequential signals corresponding to the output color difference signals (RY) and (BY), and a balanced modulator (not shown) for generating a carrier color signal from these color difference signals. ). The comb filter 2d1 is composed of adders 2d1a, 2
d1b, 2x amplification amplifier 2d1c, 1 / 4x amplification amplifier 2
It is composed of d1d. Further, the synchronization circuit 2d2 includes an adder 2d2a and two interlocking switches 2d2b, 2d2c, 1/2 which are alternately switched for each line by a line selection pulse.
It is composed of a double amplification amplifier 2d2d.

Here, the synchronization of the above color signals will be described. As shown in FIG. 3, the color filter array of a CCD image sensor (hereinafter, also referred to as CCD) 2a which is generally used at present is an array called a complementary color checkered pattern (for example, "Kono et al.," Complete Color Difference "). Line-sequential single-panel color system ”, Television Society of Japan technique VOL.8 No.44). CCD2
Ye (yellow), Mg (magenta), C in each pixel of a
The y (cyan) and G (green) color filters are overlaid.
The output of the CCD 2a is obtained by adding two pixels in the vertical direction. For example, N-line CCD2 of odd field
The a output is obtained by alternately outputting the addition output of the Ye and Mg pixels and the addition output of the Cy and G pixels (every 1H), and in the next (N + 1) line, the Ye and G pixel The addition output and the addition output of the Cy and Mg pixels (every 1H)
They are output alternately. Similarly, for example, the output of the CCD 2a of the N line in the even field includes the addition output of the pixels of Mg and Ye and the addition output of the pixels of G and Cy (1H
In the next (N + 1) line, the addition output of the G and Ye pixels and the addition output of the Mg and Cy pixels are alternately output (every 1H). .

Although there are differences in color signal separation depending on the method, basically, the outputs of the CCD 2a between the two pixels adjacent to each other in the horizontal direction of the image pickup screen are subtracted to obtain the following expression:
Color difference signals corresponding to (RY) and (BY) are extracted. N line (Mg + Ye) − (Cy + G) = 2R−G (Equation 1) (N + 1) line (Mg + Cy) − (Ye + G) = 2B−G (Equation 2) Mg = R + B, Ye = R + G, Cy = B + G R: red, G: green, B: blue. Therefore, the above-mentioned CCD 2a is for each 1H (for each scanning line).
, (2R-G), (2B-G), (2R-G), ...
Color signals are sequentially output alternately (original signal, color difference line sequential signal). R, G, and B signals are separated from this signal and well-known white balance processing, gamma processing, and the like are performed.

By the way, as is clear from the above (formula 1), in the N line, a signal corresponding to (RY), and
As is clear from the above (Equation 2), since only the signal corresponding to (BY) is obtained in the (N + 1) line,
For (N + 1) lines, upper and lower lines (that is, N lines,
It is necessary to interpolate the color difference signal corresponding to (RY) with the (N + 2) line signal. This is called vertical synchronization.

On the other hand, in the reproduction system signal processing circuit 3d, as a circuit using the 1H delay circuits 3b and 3c shown in FIG. 2, crosstalk of color signals from adjacent tracks continuously formed on the magnetic tape is performed. A comb filter for removal (shown in FIG. 5), a recursive comb filter for removal of color signal noise (shown in FIG. 6), and an H-correlation noise reduction circuit for removal of luminance signal noise (shown in FIG. 7) There is.

As shown in FIG. 5, the comb filter 4 has the 1H delay circuit 3b and the subtraction circuits 4b, 1 described above.
In the color signal reproduction processing system (frequency conversion circuit, which comprises the reproduction system signal processing circuit 3d so as to remove the crosstalk of the color signals from the adjacent tracks continuously formed on the magnetic tape, which is composed of the / 2 amplification amplifier 4c. It is provided in the latter part).

The cyclic comb filter 5 described above is also used.
As shown in FIG. 6, is composed of a subtracting circuit 5a, the above-mentioned 1H delay circuit 3b, an adding circuit 5b, a weighting circuit 5c having a weighting k, a limiter 5d, and a decorrelation muting circuit 5e. It operates as a non-recursive comb filter (when there is no correlation with a color signal) or as a recursive comb filter (when there is a correlation with a color signal) depending on whether there is a correlation with It is provided in the color signal reproduction processing system (after the frequency conversion circuit) constituting the reproduction system signal processing circuit 3d so as to remove the noise.

Further, as shown in FIG. 7, the H correlation noise reduction circuit 6 for removing the noise of the luminance signal includes a subtraction circuit 6a, 6b, 6c, a 1H delay circuit 3c, an addition circuit 6d and a 1/2 amplification amplifier. 6e, a limiter 6f, an attenuator 6g, a weighting circuit 6h having a weight k, and a switch 6i. The cyclic noise reduction circuit (switch 6
i) or a non-recursive noise reduction circuit (when the switch 6i is off), and operates in the luminance signal reproduction processing system (FM demodulation circuit) that constitutes the reproduction system signal processing circuit 3d described above. It is provided in the latter part).

[0016]

Conventionally, a camera integrated type V
As described above, the camera signal processing circuit 2 and the VTR signal processing circuit 3 which compose the video signal processing circuit 1 of TR are 1H.
The delay circuits 2b and 2c and the 1H delay circuits 3b and 3c are individually provided. Moreover, the 1H delay circuits 2b and 2c of the camera signal processing circuit 2 are used only during recording, and the 1H delay circuits 3b and 3c of the VTR signal processing circuit 3 are used only during reproduction, and as a result, the 1H delay circuit 2b is used. , 2c and 1H delay circuits 3b, 3c are not used at the same time, but they are provided in the camera signal processing circuit 2 and the VTR signal processing circuit 3, respectively, so there is a problem in terms of cost.

[0017]

In order to solve the above problems, the present invention provides a video signal processing circuit having the following configuration.

An image pickup unit having a color difference line sequential color filter array, and a video signal recording / reproducing unit for recording / reproducing a video signal based on the color difference line sequential signal output from the image pickup unit,
In order to perform vertical synchronization of the color difference line sequential signals at the time of recording and perform noise reduction processing of the reproduced video signal at the time of reproduction, there is provided a delay circuit for delaying the color difference line sequential signal or the reproduced video signal supplied by switching for a predetermined period. A video signal processing circuit characterized by being provided.

[0019]

1 is a block diagram of an embodiment of a video signal processing circuit of the present invention. The same components as those described above are designated by the same reference numerals, and the description thereof will be omitted.

Now, the video signal processing circuit 10 of the present invention is
As shown in FIG. 1, an image pickup unit (CCD image sensor) 2a having a color filter array of a color difference line-sequential system,
A video signal recording / reproducing unit (recording system signal processing circuit 3a, reproduction system signal processing circuit 3e) for recording / reproducing a video signal based on the color difference line sequential signal output from the image pickup unit 2a, and the color difference line sequential signal during recording. Vertical synchronization is performed, and noise reduction processing of the reproduced video signal is performed at the time of reproduction.
In order to perform correlation noise reduction processing and crosstalk and noise removal processing from adjacent tracks in the carrier color signal), the color difference line sequential signal or reproduction video signal (luminance signal and carrier color signal) that is switched and supplied is supplied for a predetermined period. (1H) Commonly used delay circuit for delaying (1H memory) 1
3, 14 and.

As shown in FIG. 1, the video signal processing circuit 10 described above includes a CCD image sensor 2a, a camera and a VT.
It is composed of an R signal processing circuit 11 and a switch 12. The camera / VTR signal processing circuit 11 includes a camera signal processing unit 2
d, a recording system signal processing circuit 3a, a reproduction system signal processing circuit 3e mainly composed of a DA conversion circuit / YC mixing circuit / preamplifier (all not shown), a comb filter for crosstalk removal (for example, a comb filter) 4, using a recursive comb filter 5), an H correlation noise reduction circuit 6,
1H delay circuits 13 and 14, AD conversion circuits 15 and 16, and a switch 1 that are 1H memories that store 1H period signals
It is composed of 7, 18, and 19. The switches 17 and 18 are used also as the 1H delay circuits 13 and 14 described above. In the figure, the "R" terminals constituting the switches 17, 18 and 19 are terminals connected to the movable contact at the time of recording, and similarly, the "P" terminals are terminals connected to the movable contact at the time of reproduction.

Next, the video signal processing circuit 10 having the above configuration
The recording / reproducing operation will be described.

(During recording) The original signal (color difference line sequential signal) output from the CCD image sensor 2a having the field color difference line sequential type color filter array (shown in FIG. 3) is A
GC circuit (auto gain control circuit, not shown)
After being subjected to the AGC process in (1), it is supplied to the AD conversion circuit 15 of the camera / VTR signal processing circuit 11 via the switch 12 and is AD-converted there. The AD conversion circuit 15 includes a camera signal processing unit 2d, an H correlation noise reduction circuit 6,
The digital original signals are output to the 1H delay circuit 13 via the switch 17, respectively. The 1H delay circuit 13 delays the digital original signal by 1H and outputs the 1H delay signal via the switch 18 to the next stage 1H delay circuit 14 and camera signal processing unit 2d.
Respectively output to. The 1H delay circuit 14 outputs a 2H delay signal obtained by further delaying the input 1H delay signal by 1H to the camera signal processing unit 2d.

The camera signal processing unit 2d converts three consecutive signals of three lines (original signal, 1H and 2H delay signal) into a luminance signal system (comb filter 2d1 for vertical contour enhancement) and a chrominance signal system (simultaneous synchronization described above). Processing is performed in the circuit 2d2).
In this way, the luminance signal system outputs the luminance signal generated based on the above-mentioned three signals and subjected to gamma correction and vertical contour enhancement. Further, from the color signal system, the color signals obtained by synchronizing the above three signals are separated into RGB, and then the color difference signals (R
-Y) and (B-Y) are output, and then modulated by a balanced modulator (not shown) to generate a carrier color signal. In this way, the camera signal processing unit 2d outputs the luminance signal and the carrier color signal, respectively.

The luminance signal and the carrier color signal output from the camera signal processing section 2d are supplied to the recording system signal processing circuit 3a and also output as a monitor output to a viewfinder (not shown) or the like via the switch 19. . The luminance signal supplied to the recording system signal processing circuit 3a is subjected to a required recording process in the luminance signal recording processing system and output to the YC mixing circuit as an FM modulation luminance signal. On the other hand, the carrier color signal supplied to the recording system signal processing circuit 3a is subjected to required recording processing in the color signal recording processing system and is output to the YC mixing circuit as a low frequency conversion color signal. The YC mixing circuit uses a frequency-multiplexed signal obtained by frequency-multiplexing the FM-modulated luminance signal and the low-frequency conversion color signal to a video head (neither is shown) via a recording amplifier.
Supply to. Thus, the camera / VTR signal processing circuit 1
The frequency-multiplexed signal output from 1 is successively recorded on the magnetic tape by the video head.

(At the time of reproduction) The reproduction signal obtained by scanning the signals recorded successively on the magnetic tape by the video head is supplied to the reproduction system signal processing circuit (neither is shown) through the preamplifier. It The reproduction signal supplied to the reproduction system signal processing circuit is separated and output into an FM luminance signal and a low-frequency conversion color signal by a YC separation circuit having a known structure. The separated and output FM luminance signal is demodulated by an FM demodulator (not shown) and then supplied to the AD conversion circuit 15 of the camera / VTR signal processing circuit 11 via the switch 12 and AD-converted therein. The AD conversion circuit 15 outputs a digital luminance signal to the H correlation noise reduction circuit 6. The H correlation noise reduction circuit 6 includes a switch 17, a 1H delay circuit 13,
It is connected to the switch 18, and the input digital luminance signal is subjected to H-correlation noise reduction to output a noise-reduced luminance signal to the reproduction system signal processing circuit 3e.

On the other hand, the low-frequency converted color signal separated and output by the above-mentioned YC separation circuit is supplied to the AD conversion circuit 16.
After being AD-converted here, it is frequency-converted into a carrier color signal (or color difference signal) by a frequency converter (not shown). This carrier color signal is supplied to a crosstalk removing comb filter (for example, a comb filter 4 and a recursive comb filter 5), and crosstalk and noise from adjacent tracks are removed from the carrier color signal input here. The carrier color signal thus obtained is output. The comb filter for crosstalk removal is connected to the 1H delay circuit 14 via a switch 18. The reproduction system signal processing circuit 3e transfers the digital luminance signal supplied from the H-correlation noise reduction circuit 6 and the digital carrier color signal supplied from the comb filter 4 (5) for crosstalk removal to a DA conversion circuit (not shown). Then, the respective signals are DA-converted and then frequency-multiplexed by the YC mixing circuit. Thus, the frequency-multiplexed signal obtained by frequency-multiplexing the luminance signal and the carrier color signal is output as a reproduced composite video signal to the monitor via the switch 19. Thus, the signals recorded on the magnetic tape are sent to the camera / VTR signal processing circuit 1
After the required reproduction signal processing is performed at 1, the reproduction is performed.

In the above embodiment, one of the two 1H delay circuits 13 and 14 (1H delay circuit 13) is used for noise reduction for luminance signals, and the other (1H delay circuit 14) is used for crosstalk removal of carrier color signals. However, when the emphasis is placed on improving the S / N ratio of the color signal, one is a comb filter for removing the crosstalk of the carrier color signal (shown in FIG. 5) and the other is a recursive filter for removing the noise of the color signal (see FIG. (Illustrated in 6)
(In this case, noise reduction for luminance signal is not performed).

Further, by thinning out the color signal data output from the AD conversion circuit 16 to less than half, a comb memory filter for crosstalk removal in a line memory for 1H,
Both of the recursive filters may be configured, and the remaining 1H memory may configure the H correlation noise reduction circuit for the luminance signal.

[0030]

As described above, the video signal processing circuit according to the present invention records an image pickup section having a color difference line sequential type color filter array and a video signal based on the color difference line sequential signal output from the image pickup section. The video signal recording / playback unit to be played back is vertically synchronized with the color difference line sequential signal at the time of recording, and noise reduction processing of the playback video signal is performed at the time of playback. Since it is provided with a delay circuit that delays the signal for a predetermined period, the camera signal processing circuit and the VTR signal processing circuit do not need to be separately provided, as in the conventional video signal processing circuit, but also serve as a common delay circuit. Because it is possible, it will be advantageous in terms of cost,
Further, there is an effect that the miniaturization of the camera-integrated VTR using the video signal processing circuit of the present invention can be further promoted.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a video signal processing circuit of the present invention.

FIG. 2 is a diagram showing a configuration of a video signal processing circuit of a camera-integrated VTR.

FIG. 3 is a diagram illustrating a color filter array of a color difference line sequential system.

FIG. 4 is a diagram showing a specific configuration of a camera signal processing circuit.

FIG. 5 is a diagram showing a configuration of a comb filter for removing crosstalk.

FIG. 6 is a diagram showing a configuration of a recursive comb filter.

FIG. 7 is a diagram for explaining an H-correlated noise reduction circuit.

[Explanation of symbols]

 1, 10 Video signal processing circuit 2 Camera signal processing circuit 2a CCD image sensor (imaging unit) 2b, 2c, 3b, 3c, 13, 14 1H delay circuit 3 VTR signal processing circuit 3a Recording system signal processing circuit 3d, 3e Reproduction system Signal processing circuit 11 Camera / VTR signal processing circuit

Claims (1)

[Claims] 1. An image pickup unit having a color filter array of a color difference line-sequential system, a video signal recording / reproducing unit for recording / reproducing a video signal based on a color difference line-sequential signal output from the image pickup unit, and the color difference during recording. In order to perform vertical synchronization of the line-sequential signals and perform noise reduction processing of the reproduced video signal at the time of reproduction, there is provided a delay circuit for delaying the color-difference line-sequential signal or the reproduced video signal that is switched and supplied for a predetermined period. Video signal processing circuit. [0001]