JPS63200692A - Signal separating device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of image quality caused by the deterioration of Y/C separation ability by mixing the respective output signals from a first and a second signal separating circuit as input and the output signal from a movement detecting circuit as a control signal with a prescribed ratio or providing a mixture circuit which selects the input and the control signal. CONSTITUTION:The movement part of an image is detected 300 by using at least a Y signal component obtained by executing luminance signal and chrominance signal Y/C isolation processing between the frames in a field 500 to a color image signal and Y/C separation processing between frames 400 is executed to the one of the Y signal and a C signal obtained by the Y/C separation processing in the field or the both. Then the output of the Y/C separation between the fields and the frames is mixed 600 according to the detected moving signal. Thus the crosstalk for the image with intermediate movement, perticularly in the outline part between the Y signal and the C signal is much reduced and simultaneously to that, the deterioration of the image quality caused by the deterioration of the Y/C separation effect coming from the unstability of the moving signal which occurs when the S/N of the inputted color video signal is reduced.

Description

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

Conventional technology A color image signal is obtained by frequency multiplexing a luminance signal such as an NTSC signal and a carrier chrominance signal.In separating these two types of signals, inter-frame correlation, vertical correlation (correlation between scanning lines) and horizontal correlation of the image are used. Various devices have been proposed for separating still image portions using inter-frame correlation, and moving image portions using vertical and horizontal correlation, which are intra-field processing. FIG. 5 shows an example of such a signal separation device, which is described in Japanese Patent Publication No. 15636/1983. In this device, a color image signal supplied to a signal input terminal 1 is sent to a frame memory 2, a motion detection circuit 3, an interframe luminance signal/carrier color signal (Y/C) separation circuit 4, and an intrafield Y/C separation circuit 5. The motion detection circuit 3 detects a moving part of the image by using interframe correlation between the frame memory 2 and the previous frame signal supplied via the conductor 2o, and detects the interframe Y/C. The separation circuit 4 sends a Y signal and a C signal to conductive lines 40 and 41, respectively, by performing addition and subtraction processing between two signals that are relatively different by one frame period. The intra-field Y/C separation circuit 6 processes the correlation between scanning lines and horizontal pixels of the signal supplied from the signal input terminal 1, independently or in combination, and outputs a Y signal and a Y signal to conductive lines 50 and 51, respectively. Sends a C signal. Inter-frame Y/C separation circuit 4, intra-field Y/C separation circuit 5
A first signal selection or mixing circuit 6, to which the Y signal is supplied via conductors 40 and 50, respectively, receives a control signal from the motion detection circuit 3 via a conductor 3o. 50 and the Y signal from the conducting wire 4o in the stationary portion, and sends out the KY signal to the signal output terminal 7. The second signal selection or mixing circuit 8 is also conductor 3Q
The C signal from the conductor 51 is selected for the moving part of the image, and the C signal from the conductor 41 is selected for the static part by the control signal from the motion detection circuit 3 supplied through the image, and the C signal is sent to the signal output terminal 9. do.

Problems to be Solved by the Invention As mentioned above, interframe Y/C with a frame memory
A separation circuit and an in-field Y/C separation circuit are placed in parallel, and a motion detection circuit is placed to detect the presence or absence of image movement or the degree of movement, and the outputs of the two types of Y/C separation circuits are detected for each pixel. Known signal separation devices that switch or mix the signals have the problem that they tend to produce cine-natural images due to images with intermediate motion or imperfections in the detected motion signal. For example, for an image with intermediate motion, the interframe Y/C separation circuit sends out a composite signal of the image signals of two different frames, but the interframe correlation is significantly reduced due to the motion of the image in the vertical, horizontal, or horizontal directions. Contours in diagonal directions etc. are essentially Y/C
Since separation cannot be performed, the interference between the Y signal and the C signal increases significantly, resulting in deterioration of image quality. To solve the imperfection of a motion signal, for example, in a motion detection circuit using interframe correlation, it is common to obtain an interframe difference signal and process this difference signal to obtain a motion signal.
Therefore, noise components mixed during transmission are likely to be detected as motion signals, and this erroneous motion signal deteriorates the Y/C separation performance because a part of the still image portion is processed as a motion image. The influence of this noise component on the motion detection circuit also causes part of the actual moving image portion to be omitted, so that in this case, image quality is degraded because part of the moving image portion is processed as a still image.

Means for Solving the Problems The signal separation device of the present invention inputs a frequency-multiplexed color image signal, and uses the neighborhood correlation of vertical and horizontal images in a single field to separate the luminance signal and carrier color. A first signal separation circuit that separates signals, a frame delay circuit that receives the output signal of the first signal separation circuit, and a frame delay circuit that uses signals of multiple frames from the frame delay circuit to
A second signal separation circuit that performs /C separation, a motion detection circuit that detects a moving portion of an image, and the output signals of the first and second signal separation circuits are input, and the output signal of the motion detection circuit is specified as a control signal. at least a mixing circuit for mixing or selecting at a ratio of .

Operation: The first signal separation circuit performs Y/C separation within a single field and sends the intra-field separated Y signal to the frame delay circuit. This frame delay circuit applies a delay of one frame or more to the intra-field separated Y signal, and provides the motion detection circuit with a relatively different Y signal of two frames or one frame, and the second signal separation circuit with a one frame delay. Different Y signals are supplied respectively. The motion detection circuit is 2
A moving part of an image is detected between frames, between one frame, or a combination thereof by generating a frame difference signal, and is appropriately processed and output as a motion signal. The second signal separation circuit differs by one frame 2
By adding the two Y signals with equal amplitude, the C signal component mixed in the intra-field separated Y signal is removed by inter-frame separation. A mixing circuit to which the respective outputs of the first and second signal separation circuits are supplied uses the motion signal supplied from the motion detection circuit as a control signal, and uses the signal from the second signal separation circuit in the still image portion as a control signal. The first signal separation circuit selects the second signal for the portion, and mixes it at an appropriate ratio for the intermediate motion image portion.

Embodiments Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a signal separation device in an embodiment of the present invention.
The color image signal supplied to the signal input terminal 100 is supplied to the intra-field Y/C separation circuit 500 via the conductor IC1, and Y/C separation is performed using the neighborhood correlation of the image in the vertical direction, horizontal direction, etc. This field Y/C separation circuit 5
00 extracts a two-dimensional low-frequency signal component from a color image signal in which the C signal is frequency-multiplexed with the Y signal as a two-dimensional high-frequency signal component and sends it to the conductor 501 as a Y signal.
(The configuration of the 4-separation circuit is not particularly limited. For example, a correlation non-adaptive type that processes sequentially regardless of the presence or absence of vertical correlation and horizontal correlation with a 2-dimensional low-frequency 3-wave circuit, or a non-correlation type that detects the presence or absence of correlation and Various specific configurations can be selected for the field Y/C separation circuit that adaptively switches correlation processing such as direction.
A frame delay is applied to the signal, and a Y signal delayed by two frames is sent to the conductor 2o1, and a Y signal delayed by one frame is sent to the conductor 202. The motion detection circuit 300 is connected to the conductor 5
Difference processing is performed between two relatively different Y signals supplied via 02.201, and a moving portion of the image is detected based on the generation of the difference signal. These conductors 502
．． Strictly speaking, the Y signal supplied at 201 is an in-field Y signal.
Due to the imperfection of the /C separation circuit SOO, a part of the C signal is mixed in. However, since the phase of the C signal goes around in two frames, the mixed C signal will not be mistakenly detected as a moving part. It is preferable that the motion detection circuit 300 is used between two frames, but various selections can be made in carrying out the present invention, such as between one frame or a combination of these. The inter-frame Y/C separation circuit 400 inputs Y signals that are relatively different by one frame and is supplied via conductors 202 and 503, adds them with equal amplitude, and performs inter-frame Y/C separation processing on the conductor 401. Send out. The mixing circuit 600 inputs two types of Y signals supplied via the conductor 4Q1.503, and
A motion signal supplied from the motion detection circuit 300 via the motion detection circuit 300 is mixed as a control signal. When this motion signal is at the maximum level, that is, when the degree of image motion is large, the mixing circuit 600 selects the Y signal from the conductor 503,
On the other hand, when there is no motion signal, that is, when the image is a still image, control is performed to select the Y signal on the conductor 401 side, and control is performed to mix the two Y signals for intermediate motion. Therefore, in the still image part, all the C signal components are completely removed by the inter-frame separation circuit 400 from the Y signal in which part of the C signal is mixed due to incomplete processing by the intra-field Y/C separation circuit SOO. and an intra-field Y/C separation circuit 6 for moving image parts.
The Y signal separated only by 00 is selected by the mixing circuit 600, and in the intermediate motion image part, these are mixed and the Y signal is sent to the signal=lTh output terminal 700, and the Y signal of and the signal input terminal 100 are mixed. The signal output terminal 900 is subtracted from the color image signal by the subtraction circuit 8oO.
The C signal is sent to.

FIG. 2 shows a signal separation device according to another embodiment of the present invention, which is improved in terms of separation for the C signal. In this embodiment, a subtraction circuit 801 subtracts the Y signal sent from the intra-field Y/C separation circuit 500 to the conductor 501 and the color image signal of the signal input terminal 100, and the C signal separated within the field is sent to the conductor 802. The frame memory 803 and the subtraction circuit 804 perform interframe separation processing on the C signal, and the second mixing circuit 805 performs interframe separation processing on the still image portion through the conductor 806.
The motion image portion is selected by selecting a C signal based only on intra-field separation through conductor 807 using the motion signal supplied through conductor 301, and the intermediate motion image portion is increased by mixing these signals at a predetermined ratio. The configuration is such that a quality C signal is sent to a signal output terminal 901.

FIG. 3 shows a signal separation device according to still another embodiment of the present invention, in which a subtraction circuit 801 demodulates a C signal separated within the field sent to a conductor 802 into two color difference signals and converts them into two color difference signals. The frame memory 81o1 and the adder circuit 81o2 perform interframe separation processing on the color difference signals via the time multiplexing chroma demodulation multiplexing circuit 81oO, and the color difference signals subjected to the interframe and intrafield processing of 198103.8104 are mixed in a second manner. The circuit 81o5 is configured to perform adaptive mixing control using the motion signal from the conductor 301, and has the practical effect of reducing the capacity of the frame memory 81o1 by approximately half compared to the embodiment shown in FIG. .

FIG. 4 is a simplified diagram of the configuration of the signal separation device shown in FIG. 2 showing an embodiment of the present invention. By subtracting the signal and the input color image signal in the subtraction circuit 601, the multi-signal output terminal 700
A high quality Y signal can be transmitted without degrading two-dimensional high frequency components, that is, high frequency components in the diagonal direction.

Effects of the Invention ゛The signal separation device according to the present invention detects a moving part of an image using at least the Y signal component obtained by performing intra-field Y/C separation processing on a color image signal, and C that can be obtained by Y/C separation treatment
Interframe Y/ for either or both signals.
It is characterized in that it performs C separation processing and mixes the outputs of these inter-field and inter-frame Y/C separations in accordance with the detected motion signal. Therefore, for images with intermediate motion, the crosstalk between the Y signal and the C signal in the contour area is significantly reduced, and the motion signal distortion that occurs when the S/N of the input color image signal is reduced. It has great industrial value, such as being able to prevent image quality deterioration due to deterioration of the Y/C separation effect, which is based on safety.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a signal separating device according to an embodiment of the present invention, FIGS. 2 to 4 are block diagrams of a signal separating device according to other embodiments of the present invention, and FIG. FIG. 2 is a block diagram of a conventional signal separation device. 100...Signal input terminal, 500...
Intra-field Y/C separation circuit, 200... Frame delay circuit, 300... Motion detection circuit, 400
......Inter-frame Y/C separation circuit, 600...
...Mixing circuit, 700...Signal output terminal.

Claims (4)

[Claims] (1) A first signal separation circuit that receives a frequency-multiplexed color image signal and separates a luminance signal and a carrier color signal using neighborhood correlation of vertical and horizontal images in a single field, and a first signal A frame delay circuit that receives the output signal of the separation circuit as an input, a second signal separation circuit that separates a luminance signal and a carrier color signal using the input signal and output signal of the frame delay circuit, and a still part or a moving part of an image. and a mixing circuit that uses the outputs of the first and second signal separation circuits as input signals and mixes the output of the motion detection circuit as a control signal at a predetermined ratio. Separation device. (2) The first signal separation circuit is configured to send out a luminance signal and a carrier color signal, and the frame delay circuit is configured as a first and second frame delay circuit that receives these signals as input, and the second signal separation circuit is configured to send out a luminance signal and a carrier color signal. 2. The signal separation device according to claim 1, wherein the circuit comprises a first and second frame separation circuit. (3) The first signal separation circuit is configured to send out a luminance signal and a color difference signal, and the frame delay circuit is configured as a first and second frame delay circuit that receives these luminance signals and color difference signals as input, and the second 2. The signal separation device according to claim 1, wherein the signal separation circuit is comprised of first and second interframe separation circuits. (4) The first signal separation circuit is configured to send out a luminance signal and a carrier color signal, and the frame delay circuit is configured as a first and second frame delay circuit that receives these signals as input, and the first frame is delayed. The signal separation according to claim 1, wherein a moving part of an image is detected using a signal from the circuit, and the second signal separation circuit is constituted by an interframe separation circuit using a signal from a second frame delay circuit. Device.