JPH01176188A - Moving adaptive type luminance signal chrominance signal separator - Google Patents

Abstract

PURPOSE:To attain smooth moving adaptive processing in an intermediate region between movement and standstill by varying conseutively a band width of a vertical BPF and a horizontal BPF in response to the moving coefficient obtained through the detection of movement of a picture. CONSTITUTION:Control signals mv, mh outputted by a control signal generating circuit 24 change the characteristic of variable band pass filters BPFs 14, 16 against the inputted variahle component as follows; at first, when the difference in the vertical direction is larger than the horizontal difference as the basic operation, the pass band of the variable vertical BPF 14 is widened to make the pass band of the variable horizontal BPF 16 narrow. Thus, the pass band of a chrominance signal in terms of 2-dimension is longer longitudinally but when the difference in the vertical direction is smaller than the difference in the horizontal direction, the pass band of the variable vertical BPF 14 is made narrow and the pass band of the variable horizontal BPF 16 is made wider. When both the differences have no difference, the band of the variable NPFs 14, 16 is made close, since the control signal has information of plural bits, the control is applied to smooth the change in the filter characteristic. Thus, the movement processing is made smooth.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] The present invention is a method for separating luminance signals and chrominance signals from a composite color terepinosin signal in equipment that handles television receivers (2iso, etc., ii! ii protection). The present invention relates to a luminance signal color signal separation device for extracting luminance signals and color signals.

[Prior Art] Currently, the color television standard system commonly used in television broadcasting etc. is a composite signal in which a luminance signal component and a color signal component are frequency-multiplexed. Therefore, in color television receivers and the like, it is necessary to separate and extract the luminance signal and color signal from the composite signal. Various methods have been developed to more accurately separate luminance signals and chrominance signals, and there are motion-adaptive luminance and chrominance signal separation devices that perform different separation processes depending on whether the image is a still image or a moving image. This is a motion-adaptive type of processing that performs processing in the temporal direction between frames when the image is stationary, and performs spatial processing (vertical and horizontal axes) within the field when the image is moving. High separation is possible. An example of this is the "digital decoder" described in W 61-274493.

This means that in-field processing in video is performed in the image space (2
It can be adapted to suit different dimensional conditions, and is capable of relatively good separation of luminance (No. 3 and color signals) even in moving images.

[The problem to be solved by the invention] When intra-field adaptive processing is performed in Jumei's motion-adaptive luminance signal/color signal separation device, motion-based control mixes the output of inter-frame processing and the output of intra-field processing. The output is obtained by In this case, for the 7-frame inter-frame processing, set the filter according to the completely still state, while for the intra-field processing, set the filter according to the state where only the intra-field processing is output in a completely moving state. will be carried out. In this case, in the inter-frame processing, the passband width of the chrominance signal of the spatial filter is set to be quite wide to prevent dot interference (and the bandwidth of the chrominance signal can also be widened).On the other hand, in the intra-field processing, the bandwidth of the chrominance signal is is narrowed to some extent to suppress the occurrence of cross color and a decrease in the resolution of the luminance signal.

This situation is shown in Figure 9. Although the figure shows regions on the horizontal spatial frequency axis (μ) and the temporal frequency axis (f), the vertical spatial frequency axis (ν) can be considered in the same way as U. can. Such filter settings provide ideal processing in a completely stationary state or in a moving state, but are not necessarily appropriate processing in intermediate states. Therefore, this 2
Intermediate states where the processing outputs of the species are mixed are susceptible to disturbances and resolution degradation. This situation is shown in FIG.

The spectrum of the image signal tends to concentrate on the lower part of the time axis in a stationary state, and tends to concentrate on the lower part of the spatial axis in a moving state, so there are relatively few problems.

However, the spectrum tends to spread in intermediate states where neither can be clearly determined, and the filter settings described above tend to cause crosstalk and resolution degradation.Such intermediate states are essential for smooth motion adaptation processing. This often occurs when there is a change in relatively small amplitude or when there is minute movement, and the image quality deterioration at that point can be a big problem.

However, in the conventional motion adaptive luminance signal/chrominance signal separation device,
Horizontal force BP in both inter-frame and intra-field processing
A circuit for subtracting the color signal from F and the composite signal will be included. Furthermore, the circuit for mixing the 7-frame inter-frame processing output and the intra-field processing output is separate for the luminance signal and color signal, and there are many unreasonable parts.

[Means for Solving the Problems] In order to solve the problems of the conventional motion-adaptive luminance signal/chrominance signal separation device, the present invention provides a continuous color signal pass band both horizontally and vertically depending on the degree of image motion. I am trying to change it to In addition, the control of the horizontal BPF and vertical BPF based on the movement of the image and the control of the horizontal BPF and vertical BPF based on the state and shape of the image within the field are integrated.
Regarding the PF, the processing between 7 frames and the processing within the field are the same.

That is, according to the present invention, a motion detection circuit, a temporal filter, and a vertical filter each respond to a composite color signal, and a mixing ratio of the output of the temporal filter and the output of the vertical filter are detected by the motion detection circuit. a horizontal filter for separating color signals in response to the output of the mixing means; In the motion adaptive luminance signal/chrominance signal separation device comprising means for subtracting a chrominance signal to add a luminance signal, the vertical filter is a variable vertical bandpass filter, the horizontal filter is a variable horizontal bandpass filter, and the composite vertical change detection means for detecting a difference at a sample point in the vertical direction of the image and horizontal change detection means for detecting a difference at the sample point in the horizontal direction of the image in response to the color signals, respectively;
Generating a control signal for controlling the band of the variable vertical band filter and the band of the variable horizontal band filter in response to the output signals from the vertical change detection means and the horizontal change detection means and a signal indicating the movement of the image. A motion-adaptive luminance signal/chrominance signal separation device is provided, which is characterized by being provided with a control signal generation circuit.

[Example] Examples of the present invention will be described below along with the mouth surface.

FIG. 1 is a block diagram showing an embodiment of a motion adaptive luminance signal/chrominance signal separation device of the present invention. A composite color signal converted into a digital signal by an A/D converter (not shown) is applied to an input terminal 10 (C), and is applied to a subtracter 18 via a delay compensation circuit IZ.

On the other hand, the composite color signal includes a motion detection circuit 11, a temporal band pass filter (BPF) 13, and a variable vertical BP.
It is given to F14. The output of the variable vertical BPF 14 is the subtracter 17, the multiplier 19, the adder 21 and the variable horizontal BP
The signal is applied to the subtracter 18 through the FI 6 and to the color signal output terminal 3Z. The output of the subtracter 18 is connected to a luminance signal output terminal 30. The component color signal is further given to a vertical change detection circuit 20 and a horizontal change detection circuit 22, respectively, which detect the difference between the vertical sample points and the horizontal sample point of the image in one field, as described later. , a signal indicating this difference is given to the control signal generation circuit 24. The control signal generation circuit 24 generates two control signals mv and +ah, as will be described later, and is applied to the variable vertical BPF 14 and the variable horizontal BPF 16 as band control signals via multipliers 23 and 25, respectively. Note that the control signal generation circuit 24 and the multiplier 23.2
5 constitutes a control signal generating means as a whole.

Next, the specific configuration and operation of each part will be explained. The motion detection circuit 11 has a frame memory, and detects the motion of an image by taking the difference between two consecutive 7 frames of the same pixel of the image, and its output signal is a motion coefficient. k (0≦≦1), and hereinafter the output signal of the motion detection circuit 11 will be simply referred to as a motion coefficient. .23.The 25th input signal is multiplied.

The temporal direction BPF 13 cuts high-frequency components and low-frequency components with respect to image movement between two or more frames, and its output signal is sent to one terminal of the subtractor 17 and the ten terminal of the adder 21. Given.

The vertical change detection circuit 20 and the horizontal change detection circuit 22 detect changes in pixels in the vertical and horizontal directions in one field of image i, and constitute vertical change detection means and horizontal change inspection means, respectively. When such detection is performed, color signals are multiplexed in the composite color signal, and it is necessary to avoid detecting the color subcarrier, which is a DC component of the color signal. In order to detect such a change, for example, in the case of an NTSC signal, each pixel a, b, c, d, e shown in FIG.
, in the vertical direction 1a-el or 1a-2c+
e1, horizontally 1b-dl or 1b-2c+dl
Fig. 3 shows the bath inspection area in the space frequency range in the case of such a differential signal component. In the figure, the shaded area is the area where the light is blown out, and both the high range of the luminance signal and the high range of the color signal are detected.

FIGS. 4 and 5 are block diagrams showing specific configurations of the vertical change detection circuit 20 and the horizontal change detection circuit 22 when detecting the difference between 1a-el and 1b-dl. In the figure, 40.44 is a subtracter, 4Z is a 2H delay circuit, 46
is a 4-sample delay circuit (expressed as 4T), and 43.47 is an absolute value conversion circuit.

FIG. 6 is a block diagram showing an example of a specific configuration of the control signal generation circuit 24. As shown in FIG. For example, data of 6 bits each is applied from the vertical change detection circuit 20 and the horizontal change detection circuit 22 to the latch 4S, and is applied as a 12-bit addressing signal to the ROM (read-only memory) 50 for predetermined stored data. Read the control signal. If the control signal data is 8 bits, it is applied to the latch 52, and then converted into two control signals mv and 1Ilh of 4 bits each, and applied to the multipliers 23 and 25, respectively.

Control signals aav and a output from the control signal generation circuit 24
sh is a variable band BPF 14 for input change components.
．． Let the characteristics of 16 change as follows. First, as a basic operation, when the vertical difference is larger than the horizontal difference, the passband of the variable vertical BPF 14 is widened, and the passband of the variable horizontal BPF 16 is narrowed. As a result, the passband of the color signal when viewed two-dimensionally becomes vertically elongated. Conversely, when the vertical difference is smaller than the horizontal difference,
By narrowing the passband of the variable vertical BPF14, the variable horizontal BPF
Widen the passband of PF1G. If there is no difference between the two differentials for dogs, the bands of both variable BPFs 14 and 16 are set to be close to each other. Here, since the control signal has multiple bits of information as described above, multi-stage control is performed so that the filter characteristics change smoothly.

On the other hand, in the configuration of the present invention, the control line 04 is used separately for vertical and horizontal f! , has been. This is because cross color is likely to occur when both change components are large, so the passbands of both variable BPFs 14 and 16 are narrowed in order to suppress it. In this case, if the brightness changes are large and the color changes are small, you will not be lucky, but if both the brightness changes and the color changes are large, the color signal band will become narrow (and dot interference will likely occur). In pictures like this, the narrow color signal band and dot interference are masked by changes in the luminance signal and are not very noticeable.On the other hand, the occurrence of cross color is more noticeable and is the most time consuming, so this type of processing is advantageous. become.

Two control signals vAv included in the control signal generation circuit 24
, to h is the motion coefficient in multiplier 23.25 between 7FL? multiplication is performed. This control signal tn
v , ro b are also configured to take values from O to 1 in the same way as the motion coefficients, and when the product k + n v sk lOh obtained by the multiplier 23.25 is O, the variable vertical BPF 14, the variable It is assumed that the passband width of the horizontal BPF 16 is the widest, and when it is 1, it is the narrowest. The motion coefficient takes a value of 0 when the image is stationary and 1 when the image is in the most violent motion, and changes between O and 1 depending on the motion of the image. Therefore, when =1, the output from the variable vertical BPF 14 is not attenuated by the multiplier 19 and is sent to the variable horizontal BPF 16 via only the subtracter 17 and the adder 21. In addition, the two control signals from the control code generation circuit 24 are not attenuated and are directly transmitted to the variable vertical BPF 14 and the variable horizontal BPF 14.
Is that for PF16? given.

That is, when stationary, the bandwidth of the variable horizontal IPF 16 is at its maximum regardless of the state of the intra-field signal, and as the motion output increases, the band becomes narrower in accordance with the state of the intra-field signal. FIG. 8 shows the state of this control signal. Through such processing, the variable vertical B'
The pass bands of PF14 and variable horizontal BPF16 are on the time axis,
The values are appropriately set depending on the signal states of the three elements on the horizontal and vertical axes.

Note that the control signal vav used in this control signal processing,
A precision of about 4 bits is sufficient for mh and motion coefficients, and the multipliers 23 and 25 used therein may be as simple as 4 bits x 4 bits.

The multiplier 23.25 multiplies the motion coefficient by the control signal k.
II+v, kmh may be applied to the variable vertical Bf'F 14 and the variable horizontal BPF 16 through the vertical LPF and horizontal LPF, respectively. This liver F is BP
The direction in which the filter is applied in F14.16 is 1; the theory is to make the change in the filter characteristics of BPF14.16 smooth and to prevent the signal from becoming discontinuous.

Next, an example of the configuration of the variable vertical BPF 14 is shown in FIG.

In the figure, H is an IH delay circuit that delays one line, and T is an IH delay circuit that delays one line.
0 indicates a 1-sample delay circuit that performs a 1-sample delay
The illustrated configuration obtains an output by adding the outputs of the two basic BPFs and the variation, and the variation is used by multiplying by a coefficient determined by a control signal after tap addition.

In the case shown in FIG. 7, the bandwidth at -6 dB can be changed by about twice by changing the coefficient from -co,'4 to co/4. In addition, variable horizontal B
In the case of PF16, H in the configuration of the 71st J can be replaced with 2T, so illustration thereof will be omitted.

With this configuration, a color signal is obtained as the output of the variable horizontal BPF 16, and this color signal is subtracted from the composite color signal by the subtracter 18 to obtain a luminance signal. Here, the composite color signal is processed by delay compensator 1 consisting of a delay circuit.
Since it is given to the subtracter 18 via the award circuit 12,
The color given to the subtracter 18 (has the same amount of delay as No. 3).

[Effects of the Invention] As is clear from the above detailed explanation, the motion-adaptive luminance signal/chrominance signal component B device according to the present invention adjusts the vertical 13PF according to the motion coefficient obtained by detecting the motion of the image.
The configuration is such that the bandwidth of the horizontal BPF is continuously changed, and smooth motion adaptation processing can be performed in an intermediate position between motion and stillness.

Therefore, it is possible to reduce dot interference and cross color, which were problems with conventional devices, and to reduce resolution in diagonal directions.In addition, spatial adaptive processing in the field by detecting vertical and horizontal changes is possible. By rationally combining them, only one system is required for each BPF, a subtraction circuit that subtracts the color signal from the composite color signal, and a signal mixing circuit that changes the mixing ratio according to the motion coefficient, making it possible to eliminate the need for conventional equipment. It has a simple structure.

Here, since the control of the vertical and horizontal BPFs by the eight motion detectors controls the control signal by spatial adaptive processing, only a slight increase in circuitry is required compared to the case of only spatial adaptive processing. Furthermore, since the vertical BPF and horizontal BPF are controlled by separate control signals, when there are a large number of changing components in both the horizontal and vertical directions, it is possible to suppress the occurrence of cross color by narrowing the passband of the filter in the vertical and horizontal directions. Can be done.

[Brief explanation of the drawing]

Figure 1 is a professional diagram showing an embodiment of the motion-adaptive luminance and color signal separation device of the present invention, and Figure 2 is a diagram showing the NT on the screen.
Figure 3 shows the sample points used to detect vertical and horizontal changes among the sample points obtained by sampling the SC system signal at a frequency four times that of the color subcarrier. Figure 3 is the sample point detected at the sample point in Figure 2. FIGS. 4 and 5 are diagrams showing regions on a two-dimensional spatial frequency axis, and FIGS. 4 and 5 are diagrams showing examples of specific configurations of the vertical change detection circuit 20 and horizontal change detection circuit 22 shown in FIG. 1, respectively, 6 is a diagram showing one example of a specific configuration of the control signal generation circuit 24 shown in FIG. 1, FIG. 7 is a diagram showing one example of a specific configuration of the variable vertical BPF shown in FIG. 1,
Figure 8 is a diagram showing how the variation range of the BPF band control signal obtained by spatial adaptive processing is limited by the motion coefficient, and Figure 9 is the f-μ axis in a conventional motion adaptive luminance signal/chrominance signal separation device. Figure 10 shows the luminance and chrominance signal separation area in a conventional motion adaptive luminance and chrominance signal separation device, which suggests that crosstalk and resolution degradation are likely to occur in intermediate motion states. It is a diagram. 11... Motion detection circuit 12... Delay compensation circuit 13... Time direction BPF 14
... Variable vertical BPF 16 ... Variable horizontal BPF 17.18.40.44.60a, 60b ... Subtractor 19.23.25.62 ... Multiplier 20
... Vertical change detection circuit 21.58a to 58c ... Adder 22 ...
・Horizontal change detection circuit 24...Control signal generation circuit 43.47...Absolute value conversion circuit 42.46...-Delay circuit 48.52...
・Lunch 50 ・=ROM 54a-5
4d -IH delay circuit-56a to 56g...
1 sample delay circuit inventor Sugiyama
Kenji Applicant: Japan Victor Co., Ltd. Representative: Patent Attorney Masataka Nikyu Figure 1 Figure 2 Figure 3r! ! J (a) Vertical detection area (b) Horizontal detection area 4th prisoner Fig. 5 Fig. 6 Fig. 7 Bi output Fig. 8 BPF control signal kmVkmh Dynamic --- Issei Fig. 9

Claims (7)

[Claims] (1) a motion detection circuit, a temporal filter, and a vertical filter each responsive to a composite color signal;
Mixing means that mixes the output of the temporal direction filter and the output of the vertical direction filter while changing the mixing ratio in accordance with a signal indicating the motion of the image detected by the motion detection circuit;
Motion-adaptive luminance/chrominance signal separation comprising: a horizontal filter for separating color signals in response to the output of said mixing means; and means for subtracting said color signal from a delayed signal of said composite color signal to produce a luminance signal. In the apparatus, the vertical filter is a variable vertical bandpass filter, the horizontal filter is a variable horizontal bandpass filter, and the vertical change detection detects a difference at a vertical sample point of an image in response to the composite color signal, respectively. means and a horizontal change detection means for detecting a difference at a horizontal sample point of the image; 1. A motion-adaptive luminance signal/chrominance signal separation device, comprising a control signal generating means for generating a control signal for controlling the band of the variable vertical band filter and the band of the variable horizontal band filter. (2) When the degree of change in the vertical direction indicated by the signal from the vertical change detection means is greater than the degree of change in the horizontal direction indicated by the signal from the horizontal direction change detection means, the control signal generating means detects the variable vertical The passband of the bandpass filter is widened and the passband of the variable horizontal bandpass filter is narrowed; on the other hand, when the degree of change in the vertical direction is smaller than the degree of change in the horizontal direction, the passband of the variable vertical bandpass filter is narrowed and the passband of the variable horizontal bandpass filter is narrowed. 2. The motion adaptive luminance signal/chrominance signal separation device according to claim 1, wherein the motion adaptive luminance signal/chrominance signal separation device is configured to output a control signal for widening the pass band of the horizontal band filter in multiple stages. (3) When the degree of change in the vertical direction indicated by the signal from the vertical change detection means and the degree of change in the horizontal direction indicated by the signal from the horizontal direction change detection means are both large, the control signal generating means Adaptive luminance signal/chrominance signal separation according to claim 1, wherein the adaptive luminance signal/chrominance signal separation is configured to output a control signal that narrows both the passband of the vertical bandpass filter and the passband of the variable horizontal bandpass filter. Device. (4) The control signal generating means has a storage device configured to read out a pre-stored predetermined control signal whose address is designated by the output signals from the vertical change detection means and the horizontal change detection means. A motion adaptive luminance signal/chrominance signal separation device according to claim 1. (5) The control signal generating means has a multiplier that multiplies two control signals generated by the output signals from the vertical change detecting means and the horizontal change detecting means by the signal indicating the movement, respectively. A motion adaptive luminance signal/chrominance signal separation device according to claim 1. (6) The variable vertical band filter includes a vertical filter with a fixed band that responds to the composite color signal, and changes the mixing ratio of the output signal from the vertical filter and the composite color signal in accordance with the control signal. 2. The motion-adaptive luminance signal/chrominance signal separation device according to claim 1, further comprising a second mixing means for simultaneously mixing the luminance signal and the color signal. (7) The variable horizontal band filter mixes the horizontal filter with a fixed band responsive to the output of the mixing means, and the output signal from the horizontal filter and the output of the mixing means in accordance with the control signal. 2. The motion adaptive luminance signal/chrominance signal separation device according to claim 1, further comprising a third mixing means that mixes the signals while changing the ratio.