JP2523373B2 - Motion adaptive luminance signal color signal separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a luminance signal color for extracting a luminance signal and a color signal separately from a composite color television signal in a device that handles images, such as a television receiver. The present invention relates to a signal separation device.

[Conventional technology]

Currently, the standard color television system generally used in television broadcasting is a composite signal in which a luminance signal component and a color signal component are frequency-multiplexed. Therefore, in a color television receiver or the like, it is necessary to separate the luminance signal and the color signal from the composite signal and take them out.

Therefore, various techniques for more accurately separating the luminance signal and the color signal have been developed, but as this type of device,
2. Description of the Related Art Conventionally, there is a motion adaptive type luminance signal / color signal separation device in which separation processing differs depending on whether an image is a still image or a moving image. This is a motion-adaptive process that performs processing in the time axis direction between frames when the image is stationary and performs space (vertical axis, horizontal axis) processing in the field when the image is moving. High separation is possible.

As an example, there is a "digital decoder" described in Japanese Patent Laid-Open No. 61-274493. This is because the intra-field processing in a moving image can be adaptively changed according to the spatial (two-dimensional) state of the image so that the luminance signal and the chrominance signal can be relatively well separated in the moving image.

By the way, when the intra-field adaptive processing is performed by the conventional motion adaptive luminance signal / chrominance signal separating apparatus, the control by the motion is such that the output of the inter-frame processing and the output of the intra-field processing are mixed to obtain the output. ing. In this case, the inter-frame processing sets the filter according to the completely stationary state, while the intra-field processing sets the filter according to the state in which only the intra-field processing is output in the completely moving state. It will be. Then, in the inter-frame processing, the pass band width of the color signal of the spatial filter is set to be considerably wide so that dot interference can be eliminated and the band width of the color signal can be widened. On the other hand, in the intra-field processing, the bandwidth of the color signal is narrowed to some extent to suppress the occurrence of cross color and the deterioration of the resolution of the luminance signal.

[Problems to be Solved by the Invention]

However, such a filter setting is an ideal process in a completely stationary state or a moving state, but is not necessarily an appropriate process in an intermediate state. In other words, the spectrum of the image signal tends to concentrate in the lower part of the time axis in the stationary state and in the lower part of the spatial axis in the moving state, but the spectrum tends to spread in the intermediate state where neither of them can be clearly determined. With settings, crosstalk and resolution degradation are likely to occur.

Therefore, the inventor of the present invention has developed a motion adaptive luminance signal / color signal separation device that solves such a problem, and has filed a patent application as Japanese Patent Application No. 62-336121 by the applicant of the present application.

This is because by changing the bandwidth of the spatial BPF finely according to the two-dimensional shape of the image and the degree of movement,
Highly accurate separation can be achieved in the intermediate state where no distinction can be made between the stationary state and the moving state.

However, in the apparatus of Japanese Patent Application No. 62-336121, the characteristics of the time direction filter are controlled by the motion information, and when the image moves, the intra-field separation process is switched regardless of the spatial shape of the image. Therefore, when there are many spatially oblique components of the image and the luminance signal and the color signal are spatially mixed, it is difficult to perform proper separation only by spatial processing, and crossing such as dot interference or cross color is difficult. Talk tends to occur.

The present invention has been made in view of this point, and an object of the present invention is to reduce the occurrence of crosstalk not only by control by image movement but also by control of a time direction filter by spatial change detection, thereby increasing the Achieving accurate separation.

[Means for solving the problem]

The motion-adaptive luminance signal / chrominance signal separation device of the present invention is configured such that even if motion detection is performed to some extent, more time-direction filter means is used for separation when there are many spatial oblique components in the image. In other words, the time-direction filter means is also controlled by detecting changes in the vertical and horizontal directions, and when the detection signals are large both vertically and horizontally, the time-direction pass band is narrowed even with the same motion detection amount. .

[Work]

First, if there are many diagonal components in the image, both the vertical change signal and the horizontal change signal will have large values, which will increase the ratio of the time-direction filter output included in the separation filter output. Will be used more often.

On the other hand, when the motion is strong and the motion detection signal has the maximum value, the spatial change has no relation to the control, so the temporal filter is not used, and the motion does not cause blurring or increase in crosstalk. Further, even in a flat portion or a vertical or horizontal edge, the characteristics are the same as in the conventional case, and there is no fear of dot interference in a wide range.

〔Example〕

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

FIG. 1 is a block diagram of a motion adaptive type luminance signal / color signal separation device according to an embodiment of the present invention.

In this figure, 10 is a composite signal input terminal, 12 is a delay compensation circuit, 18 is a subtracter, and 30 is a luminance signal output terminal, and these generally constitute a luminance signal extraction system. A composite color television signal digitized by an A / D converter (not shown) is input to the input terminal 10, and the delay circuit 12 converts the composite color television signal into a color signal by processing of a color signal extraction system described later. The delay is made according to the delay so that the time relationship between the two is made to coincide. In the subtracter 18, only the luminance signal is extracted by subtracting the color signal extracted by the color signal extraction system from the composite color television signal from the delay compensation circuit 12, and the subtractor 18 The output is sent from the luminance signal output terminal 30 to the subsequent system as a separated output of the luminance signal.

 Next, the color signal extraction system will be described.

Reference numeral 13 is a time direction band pass filter (BPF). A composite color television signal from the input terminal 10 is input to the time direction BPF 13, and the time band in which the color signal exists is allowed to pass therethrough.

14 is a variable vertical BPF, 17 is a subtractor, 19 is a multiplier, 21 is an adder, 16 is a variable horizontal BPF, 32 is a color signal output terminal,
A composite color television signal from the input terminal 10 is input to the variable vertical BPF 14. This variable vertical BPF14 is
It has a bandwidth for color signals in the vertical direction, and this bandwidth is variable by the vertical control signal Sv. This variable vertical
The output of BPF 14 is subtracted from the output of BPF 13 in the time direction by subtractor 17. The output of the subtractor 17 is multiplied by the time control signal St in the multiplier 19, and then added to the output of the time direction BPF 21 in the adder 21 and supplied to the variable horizontal BPF 16. The variable horizontal BPF 16 has a pass band width for color signals in the horizontal direction, and this band width is variable by the horizontal control signal Sh. The output of the variable horizontal BPF 16 is supplied to the subtracter 18 of the luminance signal system as a color signal separation output, and is also transmitted from the color signal output terminal 32 to the subsequent system.

The control signals Sv, St, Sh take values of "0" to "1" and are adjusted by the control signal generating circuit described later. The pass bands of the variable vertical BPF 14 and the variable horizontal BPF 16 are the narrowest when the control signals Sv and Sh are "1" and the widest when they are "0". Further, as described above, the output of the time direction BPF 13 is given to the minus terminal of the subtracter 17 and the adder 21 which are arranged with the multiplier 19 interposed therebetween, and the time control signal St supplied to the multiplier 19 is If it is 1, it is canceled by the input to the subtractor 17 and the input to the adder 21, and this time direction BPF13
The output of is not affected, and when it is "0", the amount input to the subtractor 17, that is, the subtracted amount becomes invalid, so the time direction
The output of BPF13 will be used to the maximum.

By continuously changing the control signal St as described above between "0" and "1", the mixing ratio of the outputs of the BPFs 13 and 14 in the subtractor 17, the multiplier 19 and the adder 21 is changed, The extraction control of the color signal according to the state of is performed.

11 is a motion detection circuit, 20 is a vertical change detection circuit, 22 is a horizontal change detection circuit, and 26 is a control signal generation circuit. The three detection circuits 11, 20, 22 respectively correspond to three-dimensional changes in the image signal. In motion detection, the inter-frame difference, which is the change in the time direction, and in vertical change detection, the line difference, which is the change in the vertical direction, In the horizontal change detection, processing is performed based on the sample difference which is a horizontal change. The control signal generating circuit 26 is adapted to generate the above-mentioned control signals Sv, Sh, St from the outputs of the motion detection signal Fm, the vertical change signal Fv, and the horizontal change signal Fh.

The motion detection circuit 11 has a frame memory and detects the motion of an image by taking the difference between two consecutive frames of the same pixel of the image. The output of the motion detection signal, Fm takes a value from 0 "to" 1 ". It is" 0 "when stationary," 1 "when the motion is the most intense, and the intermediate value varies depending on the degree of motion. This motion detection is described in detail in Japanese Patent Application No. 62-336121 filed by the present applicant.

The vertical change detection circuit 20 detects a vertical pixel change (between lines) in an image of one field, and the horizontal change detection circuit 22 horizontally (between samples) in an image of one field. It is for detecting changes in pixels. When such detection is performed, color signals are multiplexed in the composite color signal, and it is necessary not to detect the color subcarrier that is the DC component of the color signal. In order to detect such a change, for example, in the case of the NTSC system signal, the composite color signal is converted into the color subcarrier 4
When taking the difference between the pixels sampled at the doubled frequency, the subtraction is performed so as to cancel the color subcarrier. Regarding the detailed contents, please refer to
62-320965.

The control signal generating circuit 26 is constructed as shown in FIG. In this figure, the control signals Sv and Sh are the same as those in Japanese Patent Application No. 62-336121, and the feature of the present invention is the generation portion of the control signal St.
In No. 6121, the motion detection signal Fm is used as a control signal to the multiplier 19.
Was used as is, but in this method, in addition to that, the vertical change signal Fv and the horizontal change signal Fh are also used.

First, the vertical change signal Fv and the horizontal change signal Fh respectively input from the input terminals 42 and 44 are input to the control signal generation circuit 24 and the multiplier 46 obtains a multiplication value Fv × Fh. The control signal generator 24 is a table ROM, and by the addressing of, for example, 4 bits by the vertical change signal Fv or the horizontal change signal Fh, the temporary vertical control signal S before being controlled by the motion.
v'and the provisional horizontal control signal Sh 'are output. Next, when the motion detection signal Fm of about 4 bits is respectively multiplied by the multipliers 23 and 25, when the image is close to still and the value of the motion detection signal Fm is small, the values of the control signals Sv and Sh are Get smaller. This control signal Sv, Sh is the BPF 14,1 as described above.
It is input to 6 and controlled so that the band becomes wider.

On the other hand, the motion detection signal Fm input from the input terminal 40 is passed through the squarer 48 to obtain Fm ² . This Fm ² and Fm are subtractor 5
0, multiplier 52, adder 54, subtracter 17 and multiplier 1 in FIG.
9, F which is the output of the multiplier 46 by the same operation as the adder 21
Variable mixed with v × Fh. If Fv x Fh is "0", then Fm
Is output as the control signal St, Fm ² is output as the control signal St if Fv × Fh is “1”, and an intermediate value is output when Fv × Fh is between “0” and “1”. The situation is as shown in FIG.

As shown in this figure, if the value of Fv × Fh is large, the control signal
The value of St becomes smaller as it approaches Fm ² . Regarding the mixing of the BPFs 13, 14 and 16 outputs, the smaller the control signal St, the greater the mixing ratio of the time-direction BPF 13 outputs. Here, Fv × Fh does not have a large value because one of Fv and Fh is large, because it is multiplied by the other, and has a large value only when both are large. This achieves the desired processing, that is, even if there is motion, if there are many spatially oblique components of the image,
The value of the motion detection signal Fm is forcibly reduced, and the time direction BPF1
The output of 3 will be used more frequently, and it is possible to prevent crosstalk such as dot interference and cross color.

Further, the control signal generating circuit 26 has an increase of three 4-bit multipliers (a squarer is equivalent to a multiplier) and two 4-bit adder / subtractors, which is simple compared to other circuit scales.
When the table ROM is used for generating the control signal, only 4 bits × 4096 (16 kbits) ROM is added in order to output the time control signal from the ROM.

Although one embodiment has been described above, the present invention is not limited to this embodiment.

That is, first, in the apparatus of the above embodiment, the luminance signal is obtained by subtracting the color signal separated by the filter in the color signal extraction system from the composite signal. It is also applicable to an apparatus in which each extraction system is separately provided and each system obtains a separate output.

Further, in the above embodiment, the motion detection signal itself and the square value of this motion detection signal are provided, and the time control signal is obtained by mixing these, and the mixing ratio of them is determined according to the degree of change in the spatial oblique direction. The value of the time control signal is controlled by changing the value.However, various time control signal values according to the various motion detection signal values and the multiplication values of the horizontal / vertical detection signals are preset in the memory. Alternatively, the time control signal may be generated by accessing this memory with the multiplication value of the motion detection signal value and the horizontal / vertical direction detection signal and reading the preset data.

〔The invention's effect〕

As described above, according to the present invention, when the vertical change detection signal and the horizontal change detection signal are both large, the time control signal is set to be small even when there is motion. The output of the time direction filter means is used more and the occurrence of crosstalk can be reduced by controlling the time direction filter by detecting the spatial change. Therefore, the present invention detects the change of the image in all three dimensions and controls the characteristics of all the dimensions of the three-dimensional filter, which enables more appropriate and high-level separation.

[Brief description of drawings]

FIG. 1 is a block diagram of a motion adaptive type luminance signal / color signal separating apparatus according to an embodiment of the present invention, FIG. 2 is a detailed view of a control signal generating circuit thereof, and FIG. 3 is a curve showing characteristics of a time control signal. It is a figure. 10 …… Composite signal input terminal, 11 …… Motion detection circuit, 12 ……
Delay compensation circuit, 13 …… Time direction bandpass filter (BP
F), 14 …… Variable vertical BPF, 16 …… Variable horizontal BPF, 17 ……
Subtractor for mixing filter outputs, 19 ... Multiplier for mixing filter outputs, 21 ... Adder for mixing filter outputs, 20 ...
… Vertical change detection circuit, 22 …… Horizontal change detection circuit, 24 ……
Vertical / horizontal control signal generation circuit (ROM), 26 ... Control signal generation circuit, 30 ... Luminance signal output terminal, 32 ... Color signal output terminal, 46 ... Multiplier for generating mixed control signal, 48 ... Squared Device, 50 ... subtractor for mixing motion detection signals, 52 ... multiplier for mixing motion detection signals, 54 ... adder for mixing motion detection signals, Fh ... horizontal change signal, Fm ... motion detection Signal, Fv ...
... vertical change signal, Sh ... horizontal change signal, St ... time control signal, Sv ... vertical control signal.

Claims (1)

(57) [Claims] 1. A device for separating a composite color television signal into a luminance signal and a chrominance signal and obtaining a separated output thereof, wherein the composite color television signal passes in the vertical direction, horizontal direction and time direction. A three-dimensional space-time separation filter means having a bandwidth, whose output is the separated output, means for detecting a vertical change in the composite color television signal, and outputting a vertical change detection signal; A means for detecting a horizontal change in the color television signal and outputting a horizontal change detection signal; a means for detecting a motion that is a change in the time direction of the composite color television signal and outputting a motion detection signal; The smaller the detection signal value, the narrower the pass band width in the time direction of the three-dimensional space-time separation filter means, and the motion detection signal. Time for narrowing the pass band width in the time direction in the three-dimensional space-time separation filter means when the value is at an intermediate value between the maximum value and the minimum value and both the vertical change detection signal and the horizontal change detection signal are large. A motion-adaptive luminance signal / chrominance signal separation device, which comprises means for generating a direction control signal.