JPH02250566A - Noise reducer for picture signal - Google Patents

Abstract

PURPOSE:To prevent the deterioration of picture quality due to a fact that the boundary of each block is conspicuous by changing the attenuation coefficient of an attenuator for each block of the picture signal kept in a specific state with the movement detection output received from a movement detector. CONSTITUTION:The attenuation coefficient of an attenuator 4 is changed with the detection output of a movement detecting circuit (movement detector) 10. Then the attenuation coefficient of the attenuator is 4 changed with the movement detection output given from the detector 10 for each block of such a picture signal, where an end part in the direction orthogonal to a scanning line in a picture area corresponding to each block of the picture signal is shifted in the direction of the scanning line against the end part in the direction orthogonal to the scanning line in the picture area corresponding to each block of the adjacent picture signal in the direction of orthogonal to the scanning line in a reproduced picture. Thus it is possible to prevent the deterioration of picture quality due to a fact that the boundary of each block is conspicuous.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides an attenuator whose attenuation coefficient is changed by the motion detection force output from a motion detector. Regarding reducers.

(Prior Art) It is well known that noise reducers (noise reduction circuits) have been used in the past to remove noise contained in image signals and improve image quality.

The noise reducer is composed of a nonlinear low-pass filter in the time axis direction of the image signal (between fields or frames), and the image signal is stored in the frame memory and the image signal of N images ( When calculating the average of N frames of image signals), if there is no change in the image signal between frames, the image signal remains unchanged, but noise with no correlation between frames has a power of 1/N and an average amplitude of L/IN is the principle of noise reduction (noise reduction) in noise reducers, and instead of acyclic noise reducers that require the use of multiple expensive frame memories, one piece It is well known that a cyclic noise reducer can be constructed using a frame memory, and that a noise reducer can be constructed using only adders/subtractors and no multipliers.

Additionally, if the image signal changes between frames, a nonlinear low-pass filter in the time axis direction of the image signal (between fields or frames) will cause an afterimage, so a motion detector is installed. When there is movement in the image content, the detection force of the motion detector is used to reduce the attenuation coefficient of the attenuator provided in the noise reducer, so that afterimages do not occur even if there is a change in the image content. This has also been done for a long time.

(Problem to be Solved by the Invention) By the way, as described above, the attenuation coefficient of the attenuator provided in the noise reducer is reduced by the detection force output from the motion detector in response to the movement of the image content, In a noise reducer that is designed to prevent afterimages from occurring even if there is a change in image content, there is a motion detector that outputs a motion detection force for each block of an image signal having a predetermined block size. When used, the arrangement state in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is 1 as shown in FIG. 5(a). The ends in the direction perpendicular to the scanning line in the image area corresponding to each block of the image signal are adjacent in the direction perpendicular to the scanning line in the reproduced image.The scanning line in the image area corresponding to each block of the image signal is adjacent in the direction perpendicular to the scanning line in the reproduced image. When aligned with the edge in the direction orthogonal to the noise reducer, a specific attenuation coefficient is supplied to the attenuator of the noise reducer for each block, making the boundaries of each block noticeable and reducing the image quality. to degrade.

In addition, the attenuation coefficient of the attenuator provided in the noise reducer is changed by the detection force output from the motion detector in response to the movement of the image content, so that no afterimage occurs even if the image content changes. When a motion detector that outputs a motion detection force for each block of an image signal having a predetermined block size is used in a noise reducer that is If the block size is small and the image content moves quickly, the block moves in the direction in which the image content moves.

This point will be explained with reference to (a'), (b), and (d) of FIG. 6 as follows. That is, (a
) and (b) show a state in which the image content changes on the time axis, and (d) in FIG. 6 shows a block of an image signal having a small block size.

Now, in response to the change in the image content in the state shown in FIG. 6(a), motion detection information is generated in the block b1 portion of the image signal shown in FIG. 6(d), but after that, Until motion detection information is generated in the block b5 portion of the image signal in the state shown in FIG. 6(b) due to the passage of time, the block b2 portion of the image signal shown in FIG. 6(d) is Motion detection information is generated sequentially as follows: → the block b3 part of the image signal → the block b4 part of the image signal →, but the motion detection information is based on the block b 1. b 2゜b3. b4. The motion information is generated sequentially in only one block b5, and no motion information is generated in other blocks.

By the way, as mentioned above, the sequential blocks bl, b2, b
3. b4. Even if motion information is generated sequentially on the time axis for each of b5, the motion detector will operate correctly and the attenuator will be completely cut off in response to the motion detection result. If it is set to
The noise reducer works normally, but if the motion detector malfunctions, or if the attenuator is set not to shut off even when motion is detected, an afterimage will occur.

In addition, the block size for motion detection is large,
Also, the problem when the movement of the image content is slow is explained in the sixth section.
The explanation will be as follows with reference to figures (a), (b), and (c). As mentioned above, (a) and (b) in FIG. 6 show the image contents changing on the time axis.
Further, (0) in FIG. 6 indicates a block ba of an image signal having a large block size.

Now, in the block bΩ portion of the image signal shown in (Q) of FIG. 6, motion detection information is generated corresponding to the change in image content in the state of (a) of FIG. After the passage of time, motion detection information is generated in the block ba of the image signal even in the state shown in FIG. 6(b).

In this way, block b of the image signal shown in FIG. 6(c)
Since Q is large, it is not possible to distinguish between moving parts and non-moving parts in a block of one image signal, and therefore the motion detection information becomes ambiguous and the output from the motion detector becomes It is difficult to properly operate an image signal noise reducer that includes an attenuator whose attenuation coefficient is changed depending on the motion detection force applied.

(Means for Solving the Problems) The present invention provides an attenuation coefficient in which an attenuation coefficient is changed by a motion detection force output from a motion detector for each block of an image signal having a predetermined block size. In the image signal noise reducer equipped with an image signal noise reducer, the arrangement state in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is
The ends in the direction perpendicular to the scanning line in the image area corresponding to each block of the image signal are adjacent in the direction perpendicular to the scanning line in the reproduced image.The scanning line in the image area corresponding to each block of the image signal is adjacent in the direction perpendicular to the scanning line in the reproduced image. The attenuation coefficient of the attenuator is changed by the motion detection force output from the motion detector for each block of the image signal that is shifted in the direction of the scanning line with respect to the end in the direction orthogonal to The image signal noise reducer constructed as above and the noise reducer of image No. 46 including an attenuator whose attenuation coefficient is changed by the motion detection force output from the motion detector are different from each other. Motion detection is performed using blocks of image signals of each specific block size in blocks of image signals having multiple block sizes. Attenuation of the attenuator is performed by the combined output of motion detection forces output from multiple motion detectors. To provide a noise reducer for an image signal whose coefficients are changed.

(Function) The state of arrangement in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is the end of the direction orthogonal to the scanning line in the image area corresponding to each block of the image signal. As illustrated in FIG. 5(b), the direction perpendicular to the scanning line in the image area corresponding to each block of the image signal adjacent in the direction perpendicular to the scanning line in the reproduced image The attenuation coefficient of the attenuator is changed by the motion detection force output from the motion detector for each block of the image signal which is shifted in the direction of the scanning line with respect to the end of the image signal. This method solves the problem of deterioration of image quality due to conspicuous boundaries between blocks, and also solves the problem of deterioration of image quality due to conspicuous boundaries between blocks. The attenuation coefficient of the attenuator is changed by the composite output of the motion detection forces output from each of the motion detectors, so that the attenuator will not be shut off even if the motion detector malfunctions or movement is detected. To prevent an afterimage from occurring even in a case where the settings are as follows, and to ensure that motion detection information is always obtained in a moving part, so that a noise reducer can be operated satisfactorily.

(Example) Hereinafter, specific details of the image signal noise reducer of the present invention will be described in detail with reference to the accompanying drawings. FIGS. 1 to 3 are block diagrams of an embodiment of the image signal noise reducer of the present invention, FIG. 4 is a block diagram showing the configuration of a part of the motion detector, and FIGS. 5 and 6 are explanations of the operation. FIG.

FIG. 1 is a block diagram of an embodiment of the image signal noise reducer of the present invention. In this FIG. 1, 1 is the 'input terminal of the image signal to be subjected to noise reduction, and 2 is It is an output terminal.

Also, in Figure 1, 3 is an adder, 4 is an attenuator, 5 is a subtracter, and 6 is a field memory (or frame memory).
The components such as the adder 3, the attenuator 4, the subtracter 5, and the field memory (or frame memory) 6 are configured as a well-known type of cyclic noise reducer, and the attenuator 4 described above is configured as a cyclic noise reducer. The attenuation coefficient is changed depending on the detection power of the motion detection circuit 10 (motion detector 10).

The motion detection circuit 10 has a terminal 7b to which the image signal supplied to the input terminal 1 of the noise reducer for one image signal is input, and an image output from the field memory (or frame memory) 6 in the noise reducer for the image signal. A motion detection means 7 using a gradient method (a concrete example is shown in FIG. 4) includes a terminal 7a to which a signal is input.

an adder 8 to which the output signal from the output terminal 7c of the motion detecting means 7 using the gradient method described above is supplied, and a latch 47;
It is composed of a limiter 9, a counter 11, and a block size setting circuit 12.

Motion detection means 7 using the gradient method illustrated in FIG.
1986 Television Society National Conference Lecture Proceedings No. 3
It has the same configuration as that described on page 26, and includes subtracters 37, 43, 45° 46, and absolute value circuits 38 to 4.
0, Read-only memory 41.1 Delay circuit for horizontal scanning period (IHDL) 42.1 Delay circuit for pixel period (PED)
L) 44 and is based on this gradient method. The motion detecting means 7 detects the normal component of the velocity of each pixel separated by one field period (or one frame period) supplied to its input terminals 7a and 7b. Output as .

The motion detection power of each pixel separated by one field period (or one frame period) outputted from the output terminal 7c of the motion detection means 7 using the gradient method described above is added by an adder 8. .

The added value in the adder 8 described above is reset by a reset signal supplied from the counter 11, but the added value immediately before the reset in the adder 8 is reset by the latch supplied from the counter 11 described above. The signal is supplied to the limiter 9 via a latch circuit 47 that performs a latch operation using pulses.

The limiter 9 transforms the added value given to the adder 8 via the latch circuit 47 by the amplitude limiting characteristic set therein, and converts it into the motion detection port!
It is output as the motion detection force of #810, and is supplied as an attenuation coefficient to the attenuator 4 in the image signal noise reducer.

The counter 11 in the motion detection circuit 10 described above is connected to the terminal 2.
2, and each time the count value reaches a count value corresponding to the block size set in the block size setting circuit 12, a reset pulse is given to the adder 8 and added. At the same time, a latch pulse is supplied to the latch circuit 47 so that the added value immediately before the adder 8 is reset is latched by the latch circuit 47.

Therefore, in the image signal noise reducer of the present invention, the block size of the image signal used for motion detection is determined by the block size set in the block size setting circuit 12 described above. The block size is indicated by m and n in FIG.

In the image signal noise reducer of the present invention, the arrangement state in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is The ends in the direction perpendicular to the scanning line correspond to the blocks of the l-image signal adjacent in the direction perpendicular to the scanning line in the reproduced image, as illustrated in FIG. 5(b). Attenuation of the attenuator is performed by the motion detection force output from the motion detector for each block of the image signal that is shifted in the direction of the scanning line with respect to the edge in the direction orthogonal to the scanning line in the image area. It is done so that the coefficients are changed,
This solves the problem of deterioration in image quality due to conspicuous boundaries between blocks.

FIG. 2 is a block diagram of another embodiment of the image signal noise reducer of the present invention. In FIG. 1, 1 is the input terminal of the image signal to be subjected to noise reduction, and 2 is the output terminal. In addition, in FIG. 2, 13 to 16 are attenuators, 17 to 19 are field memories (or frame memories), and 20 is a synthesizer (for example, an OR circuit may be used). 16, field memory (or frame memory) 17 to 19, synthesizer 2
0 and the like are configured as well-known acyclic noise reducers, and the attenuation coefficients of the attenuators 13 to 16 are determined by the detection power of the motion detection circuit 21 (motion detector 21). It is designed to be changed by

Like the motion detection circuit 10 shown in FIG. The normal component of the velocity of each pixel that is separated by a period of one time period) is added for each block having a preset block size, and a limiter applies a predetermined amplitude limit to the added value for each block. , a plurality of attenuators 1
It is constructed as a device that generates motion detection force (damping coefficient) to be supplied to 3 to 16 individual devices.

In the image signal noise reducer of the present invention shown in FIG. 2, the arrangement state in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is The edges in the direction orthogonal to the scanning line in the image area corresponding to each block are (
As exemplified in b), the scanning line is applied to each block of the image signal adjacent in the direction perpendicular to the scanning line in the reproduced image, and to the end in the direction perpendicular to the scanning line in the corresponding image area. The attenuation coefficient of the attenuator is changed by the motion detection force output from the motion detector for each block of the image signal that is shifted in the direction of This solves the problem of image quality deterioration due to noticeable borders.

Next, FIG. 3 shows an image signal noise reducer equipped with an attenuator whose attenuation coefficient is changed by the motion detection force output from the motion detector.
The attenuator is activated by a composite output of motion detection forces output from a plurality of motion detectors that perform motion detection using blocks of image signals of respective specific block sizes in blocks of image signals each having a plurality of different block sizes. FIG. 3 is a block diagram showing a configuration example of an image signal noise reducer of the present invention in which the attenuation coefficient is changed; in FIG. 3, 1 is an input terminal of an image signal to be subjected to noise reduction; , 2 is an output terminal, 3 is an adder, 4 is an attenuator, 5 is a subtracter, and 6 is a field memory (or frame memory)
It is.

Then, the adder 3, attenuator 4. Components such as the subtracter 5 and the field memory (or frame memory) 6 are configured as a well-known type of cyclic noise reducer, as in the first embodiment shown in FIG.
The attenuation coefficient of the attenuator 4 described above is changed by the detection power of the motion detection circuit 36 (motion detector 36).

The motion detection circuit 36 has a terminal 7b to which the image signal supplied to the input terminal 1 of the image signal noise reducer is input, and a motion detection circuit 36 that receives the image signal output from the field memory (or frame memory) 6 in the image signal noise reducer. Motion detection means 7 using the gradient method (a specific configuration example is shown in FIG. 4) includes a terminal 7a to which an image signal is input, and an output terminal 7c of the motion detection means 7 using the gradient method described above. The output signals from the adders 23.27°31
is supplied to.

In the motion detection circuit 36 shown in FIG. 3, a circuit arrangement 11B1 includes an adder 23, a latch circuit 48, a limiter 24, a counter 24 and a block size setting circuit 26, and an adder 27 and a latch circuit. 49, limiter 28, counter 29, and block size setting circuit 3
0 [B2] and circuit product II consisting of an adder 31, a latch circuit 50, a limiter 32, a counter 33, and a block size setting circuit 34! What is B3?
These circuits have the same configuration as the circuit arrangement consisting of the adder 8, latch circuit, 47, limiter 9, counter 11, and block size setting circuit 12 in the motion detection circuit 10 shown in FIG. but.

Each of the circuit layouts described above [IB1 to B3 are the respective circuit layouts! ! ! ! The block size setting values set in the respective block size setting circuits 26, 30, and 34 provided in the blocks 81 to 83 are different.

The operation mode of each circuit component fi81 to B3 described above is the adder 8, latch circuit 47, limiter 9, 5 counter 11, and block size setting in the motion detection circuit 10 in FIG. 1, which was explained with reference to FIG. The operation mode of the circuit arrangement consisting of the circuit 12 is the same as that of the motion detection means 7 using the gradient method.
The motion detection power for each pixel separated by l field periods (or l frame periods) output from the output terminal 7c of each circuit component! ! Adder 23 in 1B1 to B3,
27°31 are added separately.

The added values in the adders 23, 27.31 described above are reset by the reset signals supplied from the counters 25, 29, 33. The added value is calculated by the latch circuit 4 that performs a latch operation using the latch pulses supplied from the counters 25, 29, and 33 mentioned above.
8.49.50 to the limiters 24, 28.32.

In the limiters 24, 28, and 32, the aforementioned latch circuits 48, 49
．． The added value in the adder 23, 27, 31 given via the adder 50 is transformed and supplied to the synthesis circuit 35.

The synthesis circuit 35 is composed of, for example, an OR circuit, and the output signal from this synthesis circuit 35 is sent to a motion detection circuit 36.
The motion detection signal is output as a motion detection force, and is supplied as an attenuation coefficient to the attenuator 4 in the image signal noise reducer.

Each circuit arrangement B1 to B in the motion detection circuit 36 described above
The counters 25, 29.33 in 3 count the pulses to be counted supplied to the terminal 22, and the counted value is set in each block size setting circuit 26.30.34. Each time a count value corresponding to the set value of is reached, a reset pulse is sent to the adders 23, 27 .
31 to reset the adders 23, 27, and 31, and latch circuits 48 to 50 so that the added value immediately before the adders 23, 27, and 31 are reset is latched by the latch circuits 48 to 50. Supply latch pulse to.

Therefore, in the image signal noise reducer of the present invention shown in FIG.
The attenuator 4 has a plurality of block sizes each set to 4, and whose attenuation coefficient is changed by the motion detection force output from the motion detection circuit 36. Attenuation of the attenuator is performed by a composite output of motion detection forces output from a plurality of motion detection circuits that perform motion detection using blocks of image signals each having a specific block size in blocks of image signals having a plurality of different block sizes. The coefficients are changed.

Therefore, the image signal noise reducer of the present invention shown in FIG. The attenuation coefficient of the attenuator is changed by the combined output of the motion detection forces output from each of the motion detectors, so that the attenuator will not malfunction or be shut off even if motion is detected. In order to prevent after-images from occurring even in cases where the noise is detected, the noise reducer can operate satisfactorily by ensuring that motion detection information is always obtained for moving parts.

(Effects of the Invention) As is clear from the above detailed explanation, the image signal noise reducer of the present invention detects motion output from a motion detector for each block of an image signal having a predetermined block size. In a noise reducer for image signals, which is equipped with an attenuator whose attenuation coefficient is changed by force, the noise in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is The end of the array in the direction perpendicular to the scanning line in the image area corresponding to each block of the image signal corresponds to each block of the image signal adjacent in the direction perpendicular to the scanning line in the reproduced image. Attenuation of the attenuator is performed by the motion detection force output from the motion detector for each block of the image signal that is shifted in the direction of the scanning line with respect to the edge in the direction orthogonal to the scanning line in the image area. An image equipped with an image signal noise reducer whose coefficient is changed and an attenuator whose attenuation coefficient is changed by the motion detection force output from the motion detector (No. 8) In the Soiz reducer, the motion detection power output from a plurality of motion detectors that perform motion detection using blocks of image signals of respective specific block sizes in blocks of image signals each having a plurality of different block sizes. Since this is an image signal noise reducer in which the attenuation coefficient of the attenuator is changed by the composite output, the image signal noise reducer of the present invention has a noise reducer that corresponds to each block of the image signal used for motion detection. The arrangement state of each image area in the reproduced image is such that the end in the direction perpendicular to the scanning line in the image area corresponding to each block of the image signal is.

As illustrated in FIG. 5(b), the end in the direction perpendicular to the scanning line in the image area corresponding to each block of image signals adjacent in the direction perpendicular to the scanning line in the reproduced image The attenuation coefficient of the attenuator is changed by the motion detection force output from the motion detector for each block of the image signal that is shifted in the direction of the scanning line. It is possible to solve the problem of image quality deterioration due to conspicuous boundaries, and it is also possible to use multiple motion detection methods that perform motion detection using blocks of image signals each having a specific block size in blocks of image signals each having a plurality of different block sizes. The attenuation coefficient of the attenuator is changed by the combined output of the motion detection forces output from each of the motion detectors, so that the attenuator will not malfunction or be shut off even if motion is detected. According to the present invention, the noise reducer can be operated well by ensuring that motion detection information is always obtained in moving parts so that no afterimage occurs even when The above-mentioned conventional problems can be solved satisfactorily.

[Brief explanation of drawings]

FIGS. 1 to 3 are block diagrams of an embodiment of the image signal noise reducer of the present invention, FIG. 4 is a block diagram showing the configuration of a part of the motion detector, and FIGS. 5 and 6 are explanations of the operation. FIG. 1... Input terminal of image signal to be subjected to noise reduction, 2... Output terminal, 3.23, 27.31... Adder, 4, 13-16... Attenuator, 5 .37,43.
45.46...Subtractor, 6.17-19...Field memory (or frame memory), 10°21.3
6...Motion detection circuit, 9,24,28.32...Limiter, 11,25,29.33 River counter, 12.2
6, 30. 34...Block size setting circuit, 20.
...Synthetic tree, 38~4o...Absolute value circuit. 41...Read-only memory, 42...Delay circuit for one horizontal scanning period (IHDL), 44...Delay circuit for one pixel period (PEDL), 47-50...Latch circuit, Patent applicant Japan Victor Co., Ltd. Chi 2 diagram

Claims (1)

[Claims] 1. An attenuator whose attenuation coefficient is changed by motion detection force output from a motion detector for each block of an image signal having a predetermined block size. In the image signal noise reducer used for motion detection, the arrangement state in the reproduced image of each image area corresponding to each block of the image signal used for motion detection is the same as the scanning line in the image area corresponding to each block of the image signal. The direction of the scanning line with respect to the end in the direction orthogonal to the scanning line in the image area where the end in the orthogonal direction corresponds to each block of image signals adjacent in the direction orthogonal to the scanning line in the reproduced image. An image signal noise reducer 2 and a motion detector, in which the attenuation coefficient of the attenuator is changed by the motion detection force output from the motion detector for each block of the image signal that is shifted from the motion detector. In an image signal noise reducer equipped with an attenuator whose attenuation coefficient is changed by the motion detection force output from the image signal, each specific block in the image signal blocks each having a plurality of different block sizes. A noise reducer for image signals in which the attenuation coefficient of an attenuator is changed by a composite output of motion detection forces output from a plurality of motion detectors that perform motion detection using blocks of image signals of each size.