JPS63164787A - Signal separator - Google Patents

Abstract

PURPOSE:To eliminate a remarkable change in the picture quality by applying inter- frame Y/C separation by a 1st signal separation circuit, applying two-dimension Y/C separation in the field by a 2nd signal separation circuit and connecting the circuits in series. CONSTITUTION:The 1st signal separation circuit 200 inputs a color picture signal of plural frames and applies the addition or subtraction processing making the overall gain constant to apply inter-frame luminance signal/chrominance carrier signal (Y/C) separation. Then the still part of the picture is controlled in a way that the amplitude of the relevant frame and the other frame are made equal by using a control signal from a moving detection circuit 301 and the moving part of the picture is controlled in a way that the amplitude of the relevant frame is increasing through the change in the amplitude ratio. The 2nd signal separation circuit 400 receives the output of the 1st signal separation circuit 200 to apply the Y/C separation by the correlation processing between scanning lines in the field and the still part of the picture is subjected to Y/C separation stop substantially by using the control signal from the movement detecting circuit 301 and the output of the 1st signal separation circuit 200 being the input signal is sent to the signal output terminal 700. Thus, the deterioration in the picture quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a signal separation device for separating a luminance signal (Y signal) and a carrier color signal (C signal) of a color image signal.

Conventional technology When separating these two types of signals from a color image signal, which is a frequency multiplexed luminance signal and a color signal such as an NTSC signal, inter-frame correlation and inter-scanning line correlation of the image are used, and in the still image part, inter-frame correlation is used. Various devices have been proposed for separating the motion image portions using inter-scanning correlation. FIG. 3 shows an example of such a signal separation device, which is described in Japanese Patent Publication No. 61-15635. In this device, a color image signal supplied to a signal input terminal 1 is input to a frame memory 2. Motion detection circuit 3. The inter-frame luminance signal/carrier color signal (Y/C) is supplied to an inter-frame luminance signal/carrier color signal (Y/C) separation circuit 4 and an intra-field Y/C separation circuit 6, and the motion detection circuit 3 is supplied one frame before the frame memory 2 via a conductor 2o. The interframe Y/C separation circuit 4 performs addition between two signals that are relatively different by one frame period.

Through the subtraction process, a Y signal and a C signal are sent to the conductors 40 and 41, respectively. The intra-field Y/C separation circuit 6 uses the correlation between the scanning lines of the signal supplied from the signal input terminal 1 to perform addition and subtraction processing on a plurality of scanning lines, and sends the Y signal and C signal to conductors 50 and 51, respectively. Sur. Interframe Y/C separation circuit 4. The inter-field Y/C separation circuit 6 and the respective conductors 40.
A first signal selection or mixing circuit 6 to which the Y signal is supplied via the motion detection circuit 3 via the conductor 30 selects the Y signal from the conductor 60 in moving parts of the image by means of a control signal supplied from the motion detection circuit 3 via the conductor 30. Further, in the stationary portion, the Y signal from the conducting wire 4° is selected and the Y signal is sent to the signal output terminal 7. The second signal selection or mixing circuit 8 also selects the C signal from the conductor 61 in the moving part of the image, and the C signal from the conductor 41 in the static part by the control signal from the motion detection circuit 3 via the conductor 30. A C signal is sent to the signal output terminal 9.

Problems to be Solved by the Invention As mentioned above, interframe Y/C with a frame memory
The separation circuit and the in-field Y/C separation circuit are arranged in parallel, and an image motion detection circuit is arranged to detect the presence or absence of image movement or the extent of the movement, and outputs from the two types of Y/C separation circuits are arranged. With known signal separation devices that switch or mix, the image quality deteriorates significantly when a part of the image moves or when the degree of image movement is minute, and in particular, unnatural distortion occurs in the image. I have a problem. This is, for example, the first signal selection when considering the interference of the C signal to the Y signal, that is, the dot interference, and the mixing circuit 6 is the signal output terminal when mixing two input Y signals by % by the control signal from the conductor 3o. At 7, a Y signal for a still portion is sent from the interframe Y/C separation circuit 4 in which dot interference remains in the horizontal contour portion of the image where the correlation between scanning lines is strong. Since this Y signal for the still portion is subjected to interframe addition processing, dot interference remains on the contours of two different frame signals, resulting in a significant deterioration in image quality.

Means for Solving the Problems The signal separation device of the present invention has a motion detection circuit that takes a color image signal as input and uses inter-frame correlation of the image, and a motion detection circuit that is controlled by the motion detection circuit and uses inter-frame correlation. At least a first signal separation circuit that performs Y/C separation and a second signal separation circuit that performs Y/C separation using intra-field line-to-line correlation are arranged, and these first and second signal separation circuits are connected in series. It is configured so that

Operation: The first signal separation circuit inputs color image signals of different frames, performs addition processing or subtraction processing with a fixed total gain, and performs Y/C separation. The still part of the image is controlled to have the same amplitude as that of the frame and the other frames, and the moving part of the image is controlled so as to change the amplitude ratio in the direction of increasing the amplitude of the frame. The second signal separation circuit inputs the output signal of the first signal separation circuit and performs Y/C separation by correlation processing between scanning lines in the field, but the control signal from the motion detection circuit is used to perform Y/C separation on the static part of the image. This Y/C separation operation is substantially stopped and the output of the first signal separation circuit, which is an input signal, is sent to the signal output terminal.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings, and the same reference numerals will be used for the same functions and operations as those in FIG. 3, which shows a conventional signal separation device.

FIG. 1 shows a signal separation device in an embodiment of the present invention,
In the figure, the color image signal supplied to the signal input terminal 1 is transmitted to the frame memory 2 constituting the first signal separation circuit 200.
01. The signal is supplied to one input terminal of the first coefficient circuit 202 and the motion part detection circuit 301 that constitutes the motion detection circuit 300 . The frame memory 201 supplies the color image signal of the previous frame to the other input terminals of the second coefficient circuit 203 and the moving part detection circuit 301. On one side, the first coefficient circuit 202
The adder circuit 204, which is supplied with the color image signal of the current frame and the color image signal of the previous frame at a predetermined amplitude from the second coefficient circuit 203, produces a color image whose phase is inverted from one frame to the next for a still part of the image. It operates to cancel the carrier color signal component included in the signal, and mixes the color image signals of the current frame and the previous frame supplied from the first and second coefficient circuits 202 and 203 for the moving part of the one-sided image. . The moving part detection circuit 301 detects the movement of the image based on the inter-frame difference signal between the color image signals of the current frame and the previous frame, which are relatively different by one frame, supplied via the conductor 303, and detects the motion of the image via the conductor 304. and supplies motion signals for coefficient control to the first and second coefficient circuits 202 and 203. This first. 1 for the coefficients of the second coefficient circuits 202 and 203. The coefficient of 2 is controlled by a motion signal that is a control signal, and for the static part of the image, 1 = 2 = 0.6 so that the amplitudes of the color image signals sent to the conductors 206 and 206 are equal. , and for the moving part of the image, the amplitude of the color image signal of the current frame sent by the first coefficient circuit 202 to the conductor 206 is linear in the direction of increasing 1 while maintaining 1 + 2 = 1. Alternatively, it is controlled to increase non-linearly. Therefore, for a pixel determined to be a stationary part by the moving part detection circuit 301, 1 = 2 = o, s, and for a part with complete movement, in other words, a large degree of movement, = 1. 2 = o, and for parts where the degree of movement is minute, o, 5 (K1 (1, 0, 5) K2)
The addition circuit 204 sends only the Y signal to the conductor 207 for the static part, the color image signal of the current frame for the completely moving part, and the color image signals of the current frame and the previous frame for the intermediate moving part. Sends signals mixed at a predetermined ratio. The second signal separation circuit 400 divides the output signal of the first signal separation circuit 20o supplied via the conductor 207 into two.
Vertical direction with dimensional low-pass filter circuit (two-dimensional LPF) 401,
Correlation processing in the horizontal direction is performed to remove high frequency signal components in the diagonal direction of the image. Therefore, the two-dimensional LPF 401 operates to remove or attenuate the diagonal high-frequency signal components of the C signal and the Y signal near it, and the number of scanning lines and number of horizontal pixels used for this purpose should be selected appropriately. is possible. This two-dimensional LPF 401 is the first one described above. For the static part of the image where the coefficients of the second coefficient circuits 202 and 203 are 1-2 = 0.6, the adder circuit 204 applies diagonal high frequencies to only the Y signal component sent to the conductor 207. Remove or attenuate signal components. - The power cylinder 1 signal separation circuit 200 is the color image signal conductor 2 of the current frame.
07, both the C signal component and the high-frequency signal component in the diagonal direction of the Y signal are removed or attenuated. In addition, for image parts with intermediate movements, high-frequency signal components in diagonal directions are removed or attenuated with respect to the color image signal obtained by combining the current frame and the previous frame with a predetermined amplitude ratio, so there is a correlation in the vertical and horizontal directions. The diagonal high-frequency signal components of the Y signal and C signal having the following values are passed through. Therefore, the two-dimensional LPF 401 transmits only the two-dimensional low frequency component of the Y signal to the conductor 402 in the stationary portion, and transmits a slight C signal component to the portion that has no correlation in either the vertical or horizontal directions in the moving portion. Sends a Y signal containing The subtraction circuit 403 is a two-dimensional LPF
The input and output of 401 are subtracted, a two-dimensional high-frequency signal component is sent to a conductor 404, and the two-dimensional high-frequency signal component is supplied to one input terminal of an adder circuit 406 via a switch 405. is controlled by the binarized motion signal obtained by processing the motion signal output by the moving part detection circuit 301 in the binarizing circuit 306, and supplies the two-dimensional high frequency signal component of the conductor 404 only for the still part of the image to the adding circuit 406. However, signal transmission is blocked for moving parts. A two-dimensional low-frequency signal component is supplied to the other input of this adder circuit 406 via a conductor 8402, and therefore, a second signal separation circuit 400 is connected to the Y signal output terminal 700 to separate the output signal of the first signal separation circuit 200. Two-dimensional low-pass filtering is applied only to the moving parts, and the wide-band Y signal component is sent out to the stationary parts without removing high-frequency signal components in the diagonal direction. A reduction circuit 80o is supplied with the Y signal output from the adder circuit 406 via a conductor 407 to one input terminal, and the other is supplied with the color image signal of the current frame from the signal input terminal 1. The C signal component is sent to the C signal output terminal 900 by canceling the Y signal component in the color image signal.

FIG. 2 shows the configuration of a signal separation device according to another embodiment of the present invention, in which a second signal separation circuit 400 is connected to a two-dimensional LPF 401, and the input signal and output signal of this circuit are connected via conductors 402 and 40B, respectively. and a signal selection circuit 409 controlled by a binarization circuit 306 which sends out a binarized motion signal.This signal selection circuit 409 is similar to the subtraction circuits 4o3. Switch 406. It performs an operation equivalent to the adding circuit 406, and the output signal of the first signal separation circuit 2oo is supplied via the conductor 40B for the static portion of the image, and is supplied via the conductor 402 for the portion with movement. It is controlled by the binarized motion signal to select the output signal of the two-dimensional LPF 401. Therefore, as in FIG. 1, a high-quality Y signal is sent to the Y signal output terminal Too for stationary parts without removing high-frequency signal components in the diagonal direction, and for parts with movement, intermediate movement or complete Regardless of the motion, a Y signal that has been subjected to two-dimensional low-pass filtering is sent out.

In the above description, the first and second signal separation circuits 200.4
00 for the Y signal, it goes without saying that it is within the scope of the present invention to use these for the C signal, and for this purpose, the adder circuit 204 is changed to a subtracter circuit, and the two-dimensional LP
If F401 is a two-dimensional high-pass filter circuit, C is connected to terminal 700.
The signal and the Y signal at the terminal 900 can be obtained without detracting from the advantages of the present invention, and the two-dimensional LPF 401 can be converted to the one-dimensional LPF 401.
It is of course possible to configure F and the first signal separation circuit to use more frames, and various modifications and applications are possible.

Effects of the Invention The signal separation device according to the present invention performs inter-frame Y/C separation in the first signal separation circuit, and intra-field two-dimensional Y/C separation in the second signal separation circuit, and connects these in series, and also performs stationary Y/C separation. Since the motion detection circuit controls the motion detection circuit, it is possible to perform complete Y/C separation in the static region and without any band-limiting effect. Since the Y/C separation effect can be greatly improved, significant changes in image quality or the occurrence of unnatural images due to motion adaptive control can be reduced or eliminated, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a signal separation device in one embodiment of the present invention, FIG. 2 is a block diagram of a signal separation device in another embodiment of the invention, and FIG. 3 is a block diagram of a signal separation device in a conventional example. It is. 1... Signal input terminal-201... Frame memory, 300... Motion detection circuit, 202
．． 203... Coefficient circuit, 204... Addition circuit, 401... Two-dimensional low-pass filter circuit, 40
9...Signal selection circuit, 700...Signal output terminal.

Claims (7)

[Claims] (1) A motion detection circuit that receives a color image signal as input and detects a still part or a moving part of the image using interframe correlation, and a first signal separation circuit that uses interframe correlation to separate the luminance signal and carrier color signal. circuit, and a second signal separation circuit that separates a luminance signal and a carrier color signal by using correlations in the vertical direction and horizontal direction in the field, respectively independently or in combination, and the motion detection circuit detects the motion detected by the motion detection circuit. The first signal separation circuit is controlled to suppress or stop the separation operation for moving parts of the image, and the second signal separation circuit is controlled to stop the separation operation for static parts of the image to perform wideband processing. Featured signal separation device. (2) The signal separation device according to claim 1, wherein the first and second signal separation circuits are configured to output a luminance signal, respectively. (3) The second signal separation circuit is a low-pass filter circuit, and the signal is controlled by a motion detection circuit to substantially select either the output signal of this circuit or the output signal of the first signal separation circuit. The signal separation device according to claim 2, which comprises a selection circuit. (4) The signal separation device according to claim 3, wherein the low-pass filter circuit is a two-dimensional low-pass filter circuit. (5) The signal separation device according to claim 1, wherein the first and second signal separation circuits are configured to output carrier color signals, respectively. (6) The second signal separation circuit is a high-pass filter circuit, and the signal is controlled by a motion detection circuit to substantially select either the output signal of this circuit or the output signal of the first signal separation circuit. 6. The signal separation device according to claim 5, comprising a selection circuit. (7) The signal separation device according to claim 6, wherein the high-pass filter circuit is a two-dimensional high-pass filter circuit.