JPH01176190A - Moving adaptive type luminance signal chrominance signal separator - Google Patents

Abstract

PURPOSE:To prevent occurrence of cross color in a moving picture and dot disturbance in a still picture by providing a means varying the band of a horizontal filter in response to a signal representing the movement of a picture. CONSTITUTION:A moving coefficient (k) takes a value from 0 to 1, and the value (k) is larger when the movement of the same picture element in a picture detected by a movement detection circuit 12 is large. Thus, in the case of the moving picture, the moving coefficient (k) is larger than that of a still picture, and a mixing ratio of the output of a vertical direction filter 16 is higher with respect to an output of a time direction filter 14. Moreover, a mixing ratio of an output of a horizontal direction BPF 24 is higher than that of a through-output of an adder 22 and the band of a chrominance signal output is made narrow. Conversely, in the case of a still picture, the moving coefficient (k) is small and the ratio of the through-output from the adder 22 is high, the band of the chrominance signal output is wide and it is similar in the effect to control the pass band of the horizontal direction BPF passing through the chrominance signal in response to the moving coefficient (k). Thus, occurrence of dot disturbance in a still picture and cross color in a moving picture is prevented.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for separating luminance signals and chrominance signals for separating and extracting luminance signals and chrominance signals from composite color television signals in equipment that handles images such as television receivers. Regarding equipment.

[Prior Art 1] Currently, the color television standard system generally 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. One such method is a motion adaptive luminance signal/chrominance signal separation device shown in FIG.

This method prepares 281M of temporal direction filters 14 and vertical direction filters 16 as luminance signal color signal separation filters, and uses a video signal.1) There is little change between 7 frames in each pixel of the image formed. If there is a large change between frames, use the temporal frame output 14, and if there is a large change between frames, use the vertical filter 16. A color signal is obtained by mixing the outputs of the time direction filter 14 and the vertical direction filter 16, which are subtracted by a subtracter 32 and used as a luminance signal output, by an adder 22, but the mixing ratio is changed. It is changed depending on the motion coefficient k (0≦to≦1) obtained from the detection circuit 12. That is, the outputs of the temporal filter 14 and the vertical filter 16 are multiplied by the motion coefficient k in the filters 18 and 20, and then the multiplied signals are applied to the adder 22.

Problem 1 that nmei tries to solve In the conventional motion adaptive luminance signal/chrominance signal separation device,
After mixing the outputs of the temporal filter and the vertical filter, this mixed signal is applied to a horizontal pan-doper filter (BPF) in order to separate the parts that cannot be separated. However, in the case of a fixed horizontal BPF, when obtaining the output from the temporal filter in a still image, the band of the horizontal BPF is too narrow, and the color signal is unnecessarily attenuated, resulting in the luminance signal and the color signal. will remain and dot interference will occur. Further, when obtaining an output from a vertical filter in a moving image, the band of the horizontal BPF is too wide to remove the luminance signal component superimposed on the color signal, resulting in cross color remaining. Therefore, the conventional motion-adaptive luminance signal/chrominance signal separation device has the problem that dot interference remains in still images and cross color remains in moving images.

[Means and operations for solving the problems] In order to solve the drawbacks of the above-mentioned conventional motion-adaptive luminance/chroma signal separation device, the motion-adaptive luminance/chroma signal separation device of the present invention includes the following steps:
In addition to making the temporal and vertical filters motion-adaptive (the horizontal filter is also motion-adaptive, and when the proportion of the temporal filter output is large for still images, the bandpass band of the horizontal filter is widened, and for video When the proportion of the vertical filter output is large, the bandpass band of the horizontal filter is narrowed.This is because the temporal filter output can almost completely separate the luminance signal and chrominance signal, so the horizontal bandpass band It is preferable to use a filter with a wide bandpass band without applying too many filters.
On the other hand, since the output of the vertical filter cannot be completely separated into a luminance signal and a chrominance signal, it is necessary to apply a sufficient horizontal bandpass filter, and it is desirable to use one with a narrow bandpass band. That is, according to the present invention, a motion detection circuit, a temporal filter, and a vertical filter each respond to a component not color signal, and a mixing ratio of the output of the temporal filter and the output of the vertical filter are sent to the motion detection circuit. a mixing means that mixes while changing and changing according to a signal indicating the movement of the image detected by the image;
a motion-adaptive luminance signal/chrominance signal 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; There is provided a motion-adaptive luminance signal/chrominance signal separation device, characterized in that the separation device includes means for changing the band of the horizontal filter in accordance with a signal indicating the movement of the image.

[Example] DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a motion adaptive luminance signal/chrominance signal separation device of the present invention. A video signal in which a luminance signal (Y) and a color signal (C) are superimposed, that is, a composite color television signal (hereinafter referred to as a composite color signal) is input to the input terminal 10, and a motion detection circuit 12, a temporal filter 14, They are respectively applied to the cabin direction filters 16. It is assumed that this component not color signal is converted into a digital signal by an A/D conversion circuit (not shown). This motion detection circuit 12 has a 7-frame memory, and by detecting changes in the video signal between two consecutive frames for the same pixel in an image, creates a signal representing a coefficient k corresponding to the motion. It is something.

The temporal filter 14 filters in the direction between two or more seven frames, while the vertical filter 16 filters in the vertical direction of the image in one field.

The outputs of the temporal filter 14 and the vertical filter 16 are applied to multipliers 18 and 20, respectively, and a motion coefficient k is used to calculate IP,X as follows. That is, the output of the temporal filter 14 is multiplied by (1-k), the output of the vertical filter 16 is multiplied by k, and the respective products are fed to the adder 22 for addition and mixing.

The output signal of the adder 22 is directly applied to the multiplier 26 as a through output, and is also applied to the horizontal band pass filter (BPF) 24 . The horizontal BPF applies a filter to the image of one field in the horizontal direction. The output of the horizontal BPF 24 is given to a multiplier 28. These multipliers 26 and 28 add the above (1-k) and k to their input signals, respectively! ! , and the obtained products are provided to an adder 30 for addition and mixing. The output of the adder 30 is sent to the output terminal 34 as a color signal.
The subtracter 32 subtracts the color signal from the composite color signal to obtain a luminance signal, which is applied to the output terminal 36.

The above motion coefficient takes a value from O to 1,
When the motion of the same pixel in the image detected by the motion detection circuit 12 is large, this k becomes large. Therefore, in the case of a moving image, the motion coefficient is larger than that of a still image, and the mixing ratio of the output of the vertical filter 16 is higher than that of the temporal filter 14. Also, the mixing ratio of the output of the horizontal BPF 24 becomes higher than the through output of the adder 22, and the band of the color signal output becomes narrower.On the other hand, in the case of a still image, the motion coefficient k is small, adder 22
Since the ratio of color through output increases, the band of color signal output becomes wider. Therefore, the effect is equivalent to controlling the horizontal BPF pass band through which color signals are passed in accordance with the motion coefficient k.

In the above embodiment, the motion coefficient given to the multiplier 18.20 and the motion coefficient given to the multiplier 26.28 are both k and are the same, but these motion coefficients are given a certain functional relationship. As a result, even more control can be performed. FIG. 2 is a block diagram showing such an embodiment, and the difference from the embodiment in FIG. 1 is that the multiplication circuit 1
In 8.20, 1 (0≦1≦1) is given to the motion coefficient, and 2 (0≦2≦1) is given to the multiplication circuit 26.28 as another motion coefficient.

Both k, , and k2 have a certain functional relationship, although the movement of the image is detected by the motion detection circuit 12''.

[Effects of the Invention 1] As is clear from the above detailed explanation, the motion adaptive luminance signal/chrominance signal separation device according to the present invention not only makes the horizontal 8PFLf band variable in the conventional device, but also changes it according to the motion coefficient. Since the input image signal is controlled based on whether the input image signal is a moving image or a still image, the band of 13PF in the horizontal direction can always be optimally set.

Therefore, it is possible to effectively prevent dot interference in still images and cross color in moving images, which have been problems with conventional devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the motion adaptive luminance signal/color signal separation device of the present invention, FIG. 2 is a block diagram showing an embodiment of the motion adaptive luminance signal color signal separation device, and FIG. 3 is a block diagram showing a conventional motion adaptive luminance signal color FIG. 2 is a block diagram showing a signal separation device. 12...Motion detection circuit 14...Temporal direction filter 16...Vertical direction filter 18.20.26.28...Multiplier 22.30.
...Adder 24...Horizontal BPF 32...
Subtractor inventor: Yasuyuki Katayama Exporter: Nobuyuki Kenji Meiki Tomoaki Uchida Tatsushi Takaguchi Person: Victor Japan Co., Ltd.

Claims (3)

[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. 1. A motion-adaptive luminance signal/chrominance signal separation device, characterized in that the device includes means for changing the band of the horizontal filter in accordance with a signal indicating motion of the image. (2) means for changing the band of the horizontal filter,
The second mixing means mixes the through output of the signal from the mixing means and the signal passed through the horizontal filter while changing the mixing ratio. A motion-adaptive luminance signal/chrominance signal separation device according to scope 1. (3) The second mixing means includes first and second multipliers for multiplying the signal from the mixing means and the signal from the horizontal filter by a motion coefficient or a function thereof that indicates the movement of the image, respectively. 3. The motion adaptive luminance signal/chrominance signal separation apparatus according to claim 2, further comprising an adder for adding the outputs of the first and second multipliers.