JPH07177393A - Noise removing device - Google Patents

Abstract

PURPOSE:To provide a noise removing device removing noise corresponding to the quality of noise by adjusting a feedback quantity corresponding to the movement quantity of a video signal and furthermore, corresponding to the level, the amplitude, or the kind of the video signal in the noise removing device removing noise included in the video signal. CONSTITUTION:The device is provided with a first subtraction means 12 for obtaining a difference signal between an input video signal and a delay means 11, an orthogonal transformation means 14 for an orthogonal transformation of the difference signal thus obtained, a nonlinear processing means 15 executing a nonlinear processing, an inverse orthogonal transformation means 16 for executing inverse orthogonal transformation and an attenuating means 18. By a second subtraction means 19 is obtained the difference signal between the input video signal and the output signal of the attenuation means 18. An adaptive control means 22 adaptively controls at least either the threshold value of nonlinear processing by the nonlinear processing means 15 or an attenuation quantity by the attenuation means 18 through the use of the signal level detection means 21 for the input video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise eliminating device for effectively eliminating noise contained in a video signal.

[0002]

2. Description of the Related Art With the recent development of semiconductor memory, a frame memory can be used at a low cost.
Dimensional processing is becoming popular. As for a noise eliminator used in a home VTR or a TV receiver, many devices using a frame memory have been devised. Among them, a Hadamard Transform, which is a method of orthogonal transformation, is used as a noise eliminator that utilizes the difference in three-dimensional statistical properties of video signals and random noise.
A frame recursive noise eliminator using the above has been proposed (for example, Journal of the Television Society, Vol. 37, No. 37).
12, 1983, pp56-62).

A video signal containing no noise has a large correlation in any of the horizontal, vertical, and time axes, while irregular noise has a property of having a small correlation in any of the horizontal, vertical, and time axes. . The noise removing device using the Hadamard transform has three types of the above-mentioned video signal and random noise.
This is a method for removing noise by more effectively using the difference in dimensional correlation. A frame recursive noise eliminator using Hadamard transform has a lower resolution of a moving image portion than a simple frame recursive noise eliminator without Hadamard transform under the condition that the amount of improvement in S / N ratio is the same. There is an advantage that there are few.

A conventional frame recursive denoising apparatus using Hadamard transform will be described below. FIG. 19
Figure 1 shows the configuration of a conventional noise eliminator using Hadamard transform. In FIG. 19, reference numeral 1 is a first subtractor, which subtracts an input video signal and a signal obtained by delaying an output signal obtained by removing noise from the input video signal by one to several frames to obtain a frame difference signal. Reference numeral 2 delays the noise-removed output signal by one to several frames. A serial-parallel converter 3 converts a time-series data string into a time-parallel data string so as to match the order of the Hadamard transform. Reference numeral 4 is a Hadamard converter which performs Hadamard conversion on parallel data strings. 5_1
5 to 5_k are non-linear processing units that perform non-linear processing on the data Hadamard-transformed by the Hadamard converter 4. Reference numeral 6 denotes an operation that is the reverse of the conversion operation performed by the Hadamard transformer 4, that is, Hadamard inverse transformation is performed on the data that has been subjected to the nonlinear processing by the Hadamard inverse transformer. A parallel-serial converter 7 converts a parallel data string that has undergone Hadamard inverse conversion into a serial data string. 8
The second subtractor subtracts the output of the parallel-serial converter 7 from the input video signal to obtain an output signal from which noise has been removed.

The operation of the noise eliminator configured as described above will be described below. First, the first subtractor 1 calculates the difference between the signal delayed by N (N = 1, 2, ...) Frames by the frame memory 2 and the input signal. Since the random noise and the motion component in the video signal have a small correlation in the time axis direction, they are extracted as a frame difference signal according to the noise and the signal amplitude.

The serial-parallel converter 3 temporally parallels the temporally serial frame difference signals output from the first subtractor 1 at m sample points in the horizontal direction and n lines in the vertical direction (m and n are natural numbers). Convert to different data. The serial-parallel converter 3 is composed of, for example, (n-1) line memories and (m-1) * n latches. Here, m = 4 samples, n =
The case of two lines will be described as an example.

The data of the temporally parallel pixel blocks generated by the serial / parallel converter 3 is shown in the form of a matrix (Equation 1).

[0008]

[Equation 1]

Where x₀₀~ X₁₃Pixel block composed of
The data of the clock will be described. x ₀₀Based on
x₀₁, X₀₂, X₀₃Are 1 sample and 2 samples respectively on the screen.
Sample, data located 3 samples to the right, x_TenTo
By reference, x₁₁, X₁₂, X₁₃Is 1 on the screen
Sample, 2 samples, 3 samples Data located to the right
Is. Also, x_Ten~ X₁₃Is x₀₀~ X₀₃Against the screen
The data is one line below.

The Hadamard transform unit 4 performs the Hadamard transform operation represented by (Equation 2) on the data of the temporally parallel pixel blocks of 4 sample points in the horizontal direction and 2 lines in the vertical direction. Expand to the frequency component of. However, y _ij (0 ≦ i ≦ 1, 0 ≦ j ≦ 3) is data after Hadamard transform.

[0011]

[Equation 2]

Since the random noise has a small correlation,
It is evenly distributed in each frequency component of y _{ij in} (Equation 2).

The non-linear processing units 5_1 to 5_k extract noises evenly distributed in each frequency component by Hadamard transform. FIG. 20 is an input / output characteristic diagram of the nonlinear processing units 5_1 to 5_k showing an example of the input / output relationship of the nonlinear processing units 5_1 to 5_k. Here, the output of the non-linear processing unit for y _ij which is the output of the Hadamard converter 4 is y ′ _ij . In FIG. 20, the horizontal axis represents the input y _ij and the vertical axis represents the output y ′ _ij . As can be seen from FIG. 20, when the input y _ij whose absolute value is the value “A” or more is input, the output y ′ _ij is zero.

After that, the noise components extracted by the non-linear processing units 5_1 to 5_k are subjected to the calculation represented by (Equation 3) in the Hadamard inverse transformer 6 to restore the data to real space domain components again.

[0015]

[Equation 3]

Further, after the noise component _x'ij returned to the real space domain is converted into time-series data by the parallel-serial converter 7, the second subtractor 8 converts the noise-containing input signal from the input signal. By performing the subtraction, the conventional noise removing device using the Hadamard transform realizes the noise removing action.

[0017]

However, in the above-mentioned non-linear processing units 5_1 to 5_k, the non-linear processing threshold "A" is fixed. For example, when the motion component of the video signal is equal to or less than the value "A". Is a non-linear processing unit 5_1
5_k erroneously extracts a motion component as noise and feeds it back, and thus has a problem of causing a phenomenon such as an afterimage or tailing in a moving image portion.

Further, for example, the amplitude of noise is large and the value is "A".
If it exceeds the above, the non-linear processing unit 5 cannot completely extract the noise component and returns only a part of the noise, resulting in a problem that the noise removing effect cannot be sufficiently obtained. Had.

The present invention solves the above-mentioned conventional problems, and provides a noise eliminator which does not cause deterioration such as an afterimage or tailing in a moving image portion by adjusting a feedback amount according to a movement amount of a video signal. The purpose is to provide. Another object of the present invention is to provide a noise removing device that removes noise according to the quality of a video signal by adjusting the amount of feedback according to the signal level of the video signal, the signal amplitude, or the type of the signal.

[0020]

In order to achieve this object, a noise removing device of the present invention is a delay means for delaying a signal in response to an input video signal, the input video signal and an output signal of the delay means. A first subtraction means for obtaining a difference signal between the first and second subtraction means, an orthogonal transformation means for performing an orthogonal transformation on the difference signal obtained by the first subtraction means, and a non-linear processing for the output of the orthogonal transformation means. And an inverse orthogonal transform means for performing an orthogonal inverse transform, which is an inverse transform of the orthogonal transform in the orthogonal transform means, on the output of the nonlinear transform means, and an output of the orthogonal inverse transform means is attenuated. Attenuating means, second subtracting means for obtaining a difference signal between the input video signal and an output signal of the attenuating means, signal level detecting means for detecting a signal level of the input video signal, and the signal level Out composed of an adaptive control means for adaptively controlling at least one of attenuation at threshold and the damping means of the non-linear processing in the nonlinear processing means on the basis of output to the output of said first subtracting means means.

In order to achieve the same object, the noise removing apparatus of the present invention provides a delay means for delaying a signal in response to an input video signal and a differential signal between the input video signal and the output signal of the delay means. First subtraction means for obtaining, orthogonal transformation means for performing orthogonal transformation on the difference signal obtained by the first subtraction means, and nonlinear processing means for performing non-linear processing on the output of the orthogonal transformation means An orthogonal inverse transform means for performing an orthogonal inverse transform, which is an inverse transform of the orthogonal transform in the orthogonal transform means, on the output of the non-linear processing means, an attenuating means for attenuating the output of the orthogonal inverse transform means, Second subtracting means for obtaining a differential signal between the input video signal and the output signal of the attenuating means, signal amplitude detecting means for detecting the signal amplitude of the input video signal, output of the signal amplitude detecting means, and Composed of the adaptive control means for adaptively controlling at least one of attenuation at threshold and the damping means of the non-linear processing in the nonlinear processing means on the basis of the output of one subtraction means.

In order to achieve the same object, the noise removing apparatus of the present invention provides a delay means for delaying a signal in response to an input video signal and a differential signal between the input video signal and the output signal of the delay means. First subtraction means for obtaining, orthogonal transformation means for performing orthogonal transformation on the difference signal obtained by the first subtraction means, and nonlinear processing means for performing non-linear processing on the output of the orthogonal transformation means An orthogonal inverse transform means for performing an orthogonal inverse transform, which is an inverse transform of the orthogonal transform in the orthogonal transform means, on the output of the non-linear processing means, an attenuating means for attenuating the output of the orthogonal inverse transform means, Second subtracting means for obtaining a differential signal between the input video signal and the output signal of the attenuating means, signal identifying means for identifying the signal type of the input video signal, output of the signal identifying means and the first Composed of the adaptive control means for adaptively controlling at least one of attenuation at threshold and the damping means of the non-linear processing in the nonlinear processing means based on an output of the calculation means.

[0023]

According to the present invention, the adaptive control means controls at least one of the non-linear processing threshold of the non-linear processing means and the attenuation amount of the attenuating means by the above-mentioned configuration, thereby suppressing the deterioration of the moving area image and thereby reducing the moving area image. It works so as to effectively remove noise in both the still image and the static region image.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a noise eliminating apparatus according to a first embodiment of the present invention. In FIG. 1, 10 is an input terminal to which a video signal containing noise is added. 1
1 is a frame delay means, which is a second subtraction means 19 described later.
Connected to the second subtraction means 19 and removing the noise component from the input video signal output by the second subtraction means 19 to output an N frame (N =
1, 2, ...) It delays. Reference numeral 12 is a first subtraction means, which is connected to the input terminal 10 and the frame delay means 11 and is for obtaining a difference signal between the input video signal and the signal delayed by N frames output from the frame delay means 11. . Reference numeral 13 denotes a serial / parallel conversion means, which is connected to the first subtraction means 12 and converts a temporally serial signal into temporally parallel data to generate pixel block data. Here, the size of the pixel block data is m samples in the horizontal direction and n lines in the vertical direction (m and n are natural numbers). Further, in the present embodiment, for the sake of explanation, it is assumed that m = 4 and n = 2 as an example. Here, a configuration example of the serial-parallel conversion means 13 will be described. FIG. 2 is a configuration diagram of the serial / parallel conversion means 13, wherein the serial / parallel conversion means 13 is (m-
1) × n 1-sample delay means 101 to 106 and (n
-1) The number of line delay means 107.

In FIG. 1, reference numeral 14 is an orthogonal transforming means, which is connected to the serial / parallel transforming means 13 and is connected to the serial / parallel transforming means 13.
The orthogonal transformation is applied to the data of the pixel block generated in (1). In the present embodiment, the orthogonal transform in the orthogonal transform means 14 will be described by taking the Hadamard transform as an example. The Hadamard transform has an advantage that the circuit configuration is simple and the circuit can be commonly used for the transform and the inverse transform. 15_1
15 to 15_k are k (k = m × n) non-linear processing means, which are connected to the orthogonal transformation means 14 and perform non-linear processing on the data after the orthogonal transformation to extract noise components. . Reference numeral 16 is an orthogonal inverse transforming means, which is connected to the non-linear processing means 15_1 to 15_k and performs orthogonal inverse transforming on the data extracted as the noise component.

Reference numeral 17 denotes a parallel / serial conversion means, which is connected to the orthogonal inverse conversion means 16 and outputs the orthogonally inversely converted time-parallel data (pixel block data) of m samples in the horizontal direction and n lines in the vertical direction. , By converting the average value of the sample points which are overlapped between different blocks (integration operation), the signals are converted into a serial signal in terms of time. Here, a configuration example of the parallel-serial conversion means 17 will be described. FIG. 3 is a configuration diagram of the parallel / serial conversion means 17, and the parallel / serial conversion means 17 is shown.
Is (m−1) × n 1-sample delay means 111 to 11
6 and (n−1) line delay means 117 and (m × n−)
1) It is composed of the addition means 118 to 124 and the attenuation means 125 having a gain of 1 / k. In the example, m
= 4, n = 2, the above-mentioned values are (m-1) * n = 6, n-1 = 1, and m * n-1 =
7, 1 / k = 1/8.

In FIG. 1, reference numeral 18 denotes an attenuating means, which is connected to the parallel / serial converting means 17 and reduces the gain of the signal integrated by the parallel / serial converting means 17. 19 is a second subtraction means, which is connected to the input terminal 10 and the attenuation means 18,
The noise component is removed from the input video signal by subtracting the noise component output signal of the attenuating means 18 from the input video signal. The output of the second subtraction means 19 is connected to the frame delay means 11. An output terminal 20 is connected to the second subtraction means 19 and outputs a video signal from which noise is removed.

Reference numeral 21 is a signal level detecting means for detecting the signal level of the input video signal, and its configuration example will be described. FIG. 4 is a block diagram of the signal level detecting means 21. Reference numeral 131 denotes a serial / parallel conversion means, which converts input input video signals into parallel data to generate pixel block data, and has the same function and configuration as the serial / parallel conversion means 13 described above. Further, the size of the data of the pixel block is m samples in the horizontal direction and n lines (m and n are natural numbers) in the vertical direction, but in this embodiment, for the sake of explanation, m = 4 and n = 2 are taken as an example. .
Reference numeral 132 denotes an average value calculating means for calculating an average value of the data of k (k = m × n, in the example k = 8) pixel blocks subjected to the serial / parallel conversion output from the serial / parallel converting means 131. .

Reference numeral 22 is an adaptive control means, which is a serial / parallel conversion means 13, a signal level detection means 21, and a non-linear processing means 15_.
1 to 15_k, connected to the attenuation means 18. Here, a configuration example of the adaptive control means 22 will be described. FIG. 5 is a block diagram of the adaptive control means 22. Reference numeral 141 denotes an absolute value calculation means, which is connected to the serial / parallel conversion means 13 and stores data of k (k = m × n) pixel blocks subjected to serial / parallel conversion. The absolute value is calculated. 142 is an average value calculation means,
The absolute value calculating means 141 is connected to the absolute value calculating means 14
The average value of k pieces of data of the pixel block calculated in 1 is calculated. 143 is a first control means, which is an average value calculation means 132 of the signal level detection means 21, an average value calculation means 142 of the adaptive control means 22, and a non-linear processing means 15.
Non-linear processing means 15_1 based on the absolute value average value output from the average value calculating means 142, which is connected to _1 to 15_k.
It controls the threshold value for the non-linear processing of ˜15_k. 144 is a second control means, which is connected to the average value calculating means 132 of the signal level detecting means 21, the average value calculating means 142 of the adaptive control means 22, and the attenuating means 18, and the absolute value average output from the average value calculating means 142. The feedback coefficient a in the damping means 18 is controlled based on the value.

The operation of the noise eliminator of the first embodiment constructed as above will be described below. A video signal containing noise is input from the input terminal 10. The first subtracting means 12 calculates the difference between the N-frame (N = 1, 2, ...) Delayed signal output by the frame delaying means 11 and the input video signal, and outputs a frame difference signal. The first subtraction unit 12 detects irregular noise having a small correlation between frames and a motion component of a video signal. In the static area containing no noise, the first subtraction means 12
Has an output of 0.

The time-serial signals of the noise and motion components detected by the first subtraction means 12 are converted into serial-parallel conversion means 1.
3, 3 (m-1) 1-sample delay units 111 to 116 composed of latches and (n-1) line-delay units 117 composed of line memories are used for m samples in the horizontal direction. It is converted into n lines of time-parallel data in the vertical direction. Now, as an example, description will be made assuming that m = 4 and n = 2. The time-parallel blocks generated by the serial-parallel conversion means 13 are shown in (Formula 4) in the form of a matrix.

[0033]

[Equation 4]

Here, using FIG. 6, k (K = m × n =
8) Data x₀₀~ X₀₃, X_Ten~ X ₁₃Pixel composed of
The blocks will be described. Figure 6 shows a 4x2 pixel block.
It is a configuration diagram of KU, x₀₀Based on, x₀₁, X₀₂,
x₀₃Are 1 sample, 2 samples and 3 samples respectively on the screen.
Data located to the right of the sample, x_TenBased on
And x₁₁, X₁₂, X₁₃Are 1 sample each on the screen,
The data is located to the right of two samples and three samples. Well
X_Ten~ X₁₃Is x₀₀~ X₀₃For one line on the screen
The data is located below.

4 × 2 converted by the serial / parallel conversion means 13
Pixel block data x _ij (0 ≦ i ≦ 1, 0 ≦ j ≦
3) is subjected to Hadamard transform by the orthogonal transform means 14. Data after the Hadamard transform is converted into y _ij (0 ≦ i ≦ 1, 0 ≦ j ≦
As 3), the conversion formula is shown in (Equation 5).

[0036]

[Equation 5]

By subjecting the frame difference data x _ij to Hadamard transform, an irregular noise component having a small correlation in the horizontal and vertical directions is, for example, white noise having a flat frequency characteristic. ₀₀ ~y ₁₃ are substantially evenly distributed, each level is about 1/8 of the prior Hadamard transform. On the other hand, the motion component of the video signal has frequency characteristics, and if this is subjected to Hadamard transformation, y _{00 of} (Equation 5)
Focus on a specific component of the eight components of y ₁₃ .

Next, the operation of the signal level detecting means 21, the adaptive control means 22, and the non-linear processing means 15_1 to 15_k will be described with reference to FIGS. As described above, the signal level detecting means 21 comprises the serial / parallel converting means 131 and the average value calculating means 132, and the adaptive control means 22.
Is composed of an absolute value calculation means 141, an average value calculation means 142, a first control means 143 and a second control means 144.

First, the serial / parallel conversion means 131 of the signal level detection means 21 converts the input input video signal into parallel data to generate pixel block data, and the average value calculation means of the signal level detection means 21. The serial-to-parallel conversion output by the serial-to-parallel conversion unit 131 by k
The average value of the data of the pixel blocks (k = m × n, k = 8 in the example) is calculated. The output of the average value calculation means 132 is the first control means 143 and the second control means 144.
Is output to. The average value output by the average value calculation unit 132 indicates the average signal level of the input video signal. For example, if the input video signal is a luminance signal, it indicates that the luminance is high when this average value is large, and vice versa. Shows that the brightness is low when the average value is small.

Further, the absolute value calculating means 141 calculates the absolute value of the data of the 4 × 2 pixel blocks which are temporally parallelized of the frame difference signal. Next, the average value calculation means 142 calculates the average value of the calculated absolute values. This average value is regarded as the amount of movement of the pixel block portion on the screen.

The first control means 143 is the average value calculation means 1
Non-linear processing means 15_1 to 15 based on the output of 42.
In _k, a threshold value for non-linear processing on the data of the pixel block consisting of eight components y _{00 to} y ₁₃ is generated. Here, the non-linear processing means 15_1 to 15_k shown in FIG.
An example of the input / output relation of is shown. FIG. 7 shows the non-linear processing means 15_
In the input / output characteristic chart of 1 to 15_k, if the absolute value of the input is less than or equal to the threshold value (indicated by the value "A" in the figure), output is performed with linear characteristics, and if the absolute value of the input is greater than or equal to the threshold value, the output A so-called limiter operation of setting the threshold value, that is, a so-called threshold value is performed. Here, if the output of the average value calculation means 142 is large, the frame difference data is regarded as the motion component of the video signal, and the threshold value in the non-linear processing means 15_1 to 15_k is reduced, whereby the feedback amount of the signal of the motion component is reduced. To reduce the deterioration of moving images. On the other hand, if the output of the average value calculation means 142 is small, the frame difference data is regarded as a noise component, and the nonlinear processing means 15_1 to 15_k.
The noise removal effect is increased by increasing the threshold value in (2), that is, by increasing the amount of noise feedback.

Further, the first control means 143 operates the generated threshold value based on the output of the average value calculation means 132 of the signal level detection means 21. Average value calculation means 1
When the average value output by 32 is large, for example, it is considered that a video signal with high luminance is input, and the thresholds in the nonlinear processing means 15_1 to 15_k are reduced, so that the signal with respect to the video signal with high luminance is output. The amount of feedback is reduced to suppress the amount of noise removal in high-brightness video. On the other hand, the average value calculation means 1
When the average value output from 32 is small, for example, it is considered that a video signal with low luminance is input, and the threshold value in the nonlinear processing means 15_1 to 15_k is increased, that is, the feedback amount of noise is increased to reduce the noise. Increases the noise removal effect when displaying luminance video signals.

Here, an example of the input / output relationship in the first control means 143 is shown in FIG. FIG. 8 shows the first control means 1.
43 is an input / output characteristic diagram of 43, showing the relationship between the average value calculating means 142 and the thresholds of the nonlinear processing means 15_1 to 15_k, and showing how the output of the average value calculating means 132 changes the input / output characteristics.

The outputs non-linearly processed by the non-linear processing means 15_1 to 15_k are made to correspond to the input yij and y '.
ij. The orthogonal inverse transform means 16 performs the 4 × 2 order Hadamard inverse transform shown in ( _Equation 6) on y ′ _ij . Here, x ′ _ij is the output of the orthogonal inverse transform means 16.

[0045]

[Equation 6]

As can be seen from (Equation 6), the coefficient 1/8
The Hadamard inverse transformation formula is the same as the Hadamard transformation formula except for the presence or absence of.

[0047] Then, in the inverse orthogonal transform unit 16, Hadamard inverse transformed data data x parallel to serial conversion means 17 4 × 2 pieces of temporally parallel pixel block shown in FIG. 3 _'ij
(0 ≦ i ≦ 1, 0 ≦ j ≦ 3) is converted into eight temporally serial data, and at sample points where different pixel blocks overlap, the blocks are averaged.

Then, the parallel / serial converted data is multiplied by the feedback coefficient generated by the adaptive control means 22 in the attenuation means 18.

Signal level detection means 21 and adaptive control means 2
2 and the operation of the damping means 18 will be described with reference to FIGS. Serial-parallel conversion means 131, average value calculation means 132,
The operations of the absolute value calculation means 141 and the average value calculation means 142 are exactly the same as those described above. Second control means 14
Reference numeral 4 denotes the attenuation means 1 according to the output of the average value calculation means 142.
At 8, the gain, that is, the feedback coefficient a (0 ≦ a <1) is controlled.
Here, if the output of the average value calculation means 142 is large,
By considering the frame difference data as the motion component of the video signal and reducing the feedback coefficient a in the attenuator 18, the feedback amount of the signal of the motion component is reduced and the deterioration of the moving image is suppressed.
On the other hand, when the output of the average value calculating means 142 is small, the frame difference data is regarded as a noise component and the feedback coefficient a is increased by the attenuating means 18, that is, the feedback amount of noise is increased and the noise removing effect is increased. To do.

Further, the second control means 144 operates the feedback coefficient a generated based on the output of the average value calculation means 132 of the signal level detection means 21. When the average value output from the average value calculating means 132 is large, for example, it is considered that a video signal with high luminance is input, and the feedback coefficient a in the attenuating means 18 is reduced, so that the video signal with high luminance is compared. The amount of signal feedback is reduced to suppress the amount of noise removal in high-luminance video. On the other hand, when the average value output by the average value calculation means 132 is small, it is considered that a video signal having low luminance is input, and the feedback coefficient a is increased by the attenuation means 18, that is, the feedback amount of noise is increased. Thus, the noise removal effect at the time of displaying a low-luminance video signal is increased.

Here, an example of the input / output relationship in the second control means 144 is shown in FIG. FIG. 9 shows the second control means 1.
44 is an input / output characteristic diagram of 44, showing the relationship between the average value calculating means 142 and the feedback coefficient in the damping means 18, and showing how the input / output characteristics are changed by the output of the average value calculating means 132.

Finally, the second subtraction means 19 subtracts the data extracted as noise from the input video signal to obtain a noise-free video signal with little deterioration of the moving image at the output terminal 20. be able to.

As described above, according to this embodiment, the input terminal 10 to which the video signal is applied and the frame delay means for delaying the output of the second subtraction means by N frames (N = 1, 2 ...). 11, input video signal and frame delay means 11
From the output signal from the first subtraction means 12 and serial-parallel conversion means 13 that converts temporally serial frame difference data into temporally parallel pixel block data.
, Orthogonal transformation means 14 for performing orthogonal transformation, and non-linear processing means 15 for performing non-linear processing on the orthogonally transformed data.
_1 to 15_k, an orthogonal inverse transform means 16 that performs an inverse orthogonal transform on the non-linearly processed data, and data of pixel blocks that are temporally parallel to the orthogonally inversely converted data are serially temporally arranged. After conversion into data, a parallel-serial conversion means 17 for averaging overlapping data among a plurality of blocks, an attenuation means 18 for multiplying temporally serialized data by a feedback coefficient, and extraction from an input video signal The second subtraction means 19 for subtracting the generated noise component, the signal level detection means 21 for detecting the signal level of the input video signal, the thresholds of the nonlinear processing means 15_1 to 15_k, and the feedback coefficient in the attenuation means 18 are input. By including the adaptive control means 22 that controls according to the signal level and the frame difference signal, the moving area and the still area can be controlled in a state where the deterioration of the moving image is small. Noise component in the square can be effectively removed.

The nonlinear processing means 15_1 to 15_k
The input / output characteristics in (1) are not limited to those shown in FIG. 7, and for example, the inclination of the characteristic represented by a straight line may not be 1, and the characteristic represented by a non-linear characteristic may be used. The input / output relationship of the first control means 143 and the input / output characteristics of the second control means 144 are not limited to those shown in FIGS. 8 and 9.

Further, in the present embodiment, the data of the pixel block is continuously defined by m samples in the horizontal direction and n lines in the vertical direction (m and n are natural numbers). However, for example, m samples are arranged at intervals of p samples in the horizontal direction. , N lines at intervals of q lines in the vertical direction (where m, n, p, and q are natural numbers) may be defined. However, in this case, the q line delay means may be used as the line delay means used in the serial / parallel conversion means or the parallel / serial conversion means, and the p sample delay means may be used as the 1 sample delay means.

The signal level detecting means 21 calculates the signal level using the serial / parallel converting means 131 and the average value calculating means 132, but calculates the signal level using a two-dimensional low pass filter (low pass filter). May be.

The second embodiment of the present invention will be described below with reference to the drawings. FIG. 10 shows a block diagram of a noise removing apparatus according to the second embodiment of the present invention. In the present embodiment, those having the same configurations and functions as those of the elements of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 41 is a signal amplitude detecting means for detecting the signal amplitude of the input video signal, and its configuration example will be described below. FIG. 11 is a block diagram of the signal amplitude detecting means 41. Reference numeral 201 denotes a serial / parallel conversion means, which converts input input video signals into parallel data to generate pixel block data, and has the same function and configuration as the serial / parallel conversion means 13 described above. Further, the size of the data of the pixel block is m samples in the horizontal direction and n lines (m and n are natural numbers) in the vertical direction, but in this embodiment, for the sake of explanation, m = 4 and n = 2 are taken as an example. . Two
Reference numeral 02 denotes an amplitude value calculation means, which is k serial-parallel converted (k = m × n, k in the example) output from the serial-parallel conversion means 201.
= 8), the amplitude value of the data of the pixel block is calculated.

Reference numeral 42 denotes an adaptive control means, which is a serial / parallel conversion means 33, a signal amplitude detection means 41, and a non-linear processing means 35_1.
~ 35_k, connected to the attenuation means 38. Here, a configuration example of the adaptive control means 42 will be described. FIG. 12 is a block diagram of the adaptive control means 42. Reference numeral 211 denotes an absolute value calculation means, which is connected to the serial / parallel conversion means 33 and calculates the absolute value of the data of k (k = m × n) pixel blocks which are serial / parallel converted. 212 is an average value calculation means,
The absolute value calculating means 21 is connected to the absolute value calculating means 21.
The average value of k pieces of data of the pixel block calculated in 1 is calculated. A first control unit 213 is connected to the amplitude value calculation unit 202, the average value calculation unit 212, and the non-linear processing units 35_1 to 35_k, and the average value calculation unit 2
The threshold value for nonlinear processing of the nonlinear processing means 35_1 to 35_k is controlled based on the absolute value average value output from 12. A second control unit 214 is connected to the amplitude value calculation unit 202, the average value calculation unit 212, and the attenuation unit 38, and based on the absolute value average value output from the average value calculation unit 212, The feedback coefficient a is controlled.

The operation of the noise eliminator of the second embodiment configured as above will be described below by comparing its operation with that of the first embodiment. An input video signal containing noise is added to the input terminal 10, the first subtraction means 12 calculates the difference between the input video signal and the output signal of the frame delay means 11, and the serial / parallel conversion means 13 performs temporal parallel processing. The operation up to the point where the pixel block data composed of m × n data is generated and the m × n Hadamard transform is performed by the orthogonal transform means 14 is the same as in the first embodiment.

In the first embodiment, the signal level detecting means 2
1 is used to control the adaptive control means 22, but in the second embodiment, the adaptive control means 4 is controlled by using the signal amplitude detection means 41.
Control 2

Signal amplitude detection means 41, adaptive control means 4
2. The operation of the non-linear processing means 15_1 to 15_k will be described with reference to FIGS. As described above, the signal amplitude detecting means 41 comprises the serial / parallel converting means 201 and the amplitude value calculating means 202, and the adaptive control means 42.
Is composed of an absolute value calculation means 211, an average value calculation means 212, a first control means 213 and a second control means 214.

First, the serial-parallel conversion means 201 of the signal amplitude detection means 41 converts the input input video signal into parallel data to generate pixel block data, and the amplitude value calculation means 202 of the signal amplitude detection means 41. Then, the serial-to-parallel conversion output by the serial-to-parallel conversion means 201 (k = m ×).
The amplitude value of the data of the pixel block of n, k = 8 in the example) is calculated. The output of the amplitude value calculation means 202 is output to the first control means 213 and the second control means 214.
The amplitude value output by the amplitude value calculation means 202 indicates a pattern displayed by the input video signal. For example, if the input video signal is a luminance signal, a fine pattern is displayed when the amplitude value is large. On the contrary, when the amplitude value is small, a smooth picture is displayed.

The absolute value calculating means 211 calculates the absolute value of the data of the 4 × 2 pixel blocks of the frame difference signal which are temporally parallelized. Next, the average value calculating means 212 calculates the average value of the calculated absolute values. This average value is regarded as the amount of movement of the pixel block portion on the screen.

The first control means 213 is the average value calculation means 2
Based on the output of 12, the nonlinear processing means 35_1-35
In _k, it generates a threshold value for the non-linear processing for the data y ₀₀ of 8 components ~y ₁₃ pixel block. Here, when the output of the average value calculation means 212 is large, the frame difference data is regarded as the motion component of the video signal, and the threshold value in the non-linear processing means 35_1 to 35_k is reduced, whereby the feedback amount of the signal of the motion component is reduced. To reduce the deterioration of moving images. On the other hand, if the output of the average value calculation means 212 is small, the frame difference data is regarded as a noise component and the threshold value in the nonlinear processing means 35_1 to 35_k is increased, that is, the amount of noise feedback is increased, and the noise removal effect is increased. To increase.

Further, the first control means 213 operates the threshold value generated based on the output of the amplitude value calculation means 202 of the signal amplitude detection means 41. Amplitude value calculation means 20
When the amplitude value output by 2 is large, it is considered that a fine pattern is displayed, for example, and the nonlinear processing means 35_1 to 35_1
By reducing the threshold value of 35_k, the amount of noise feedback is reduced and the amount of noise removal is suppressed so that the image quality deterioration is suppressed with respect to the video signal with a fine pattern. On the other hand, when the amplitude value output by the amplitude value calculation means 202 is small, for example, it is considered that a smooth picture is displayed, and the threshold value in the nonlinear processing means 35_1 to 35_k is increased, that is, the feedback amount of noise is increased. Then, the noise removal effect is increased for the video signal having the smooth pattern.

Here, an example of the input / output relationship in the first control means 213 is shown in FIG. FIG. 13 is an input / output characteristic diagram of the first control means 213, and the average value calculation means 212
And the threshold values of the non-linear processing means 35_1 to 35_k, and how the input / output characteristics are changed by the output of the amplitude value calculation means 202.

Orthogonal transformation means 36, parallel-serial transformation means 37
The operation of is similar to that of the first embodiment. Then, the parallel-serial converted data is multiplied by the feedback coefficient generated by the adaptive control means 42 in the attenuation means 38.

Signal amplitude detection means 41, adaptive control means 42
Then, the operation of the damping means 38 will be described with reference to FIGS. Serial-parallel conversion means 201, amplitude value calculation means 20
2. The operations of the absolute value calculation means 211 and the average value calculation means 212 are completely the same as those described above. The second control unit 214 controls the gain, that is, the feedback coefficient a (0 ≦ a <1) by the attenuating unit 38 according to the output of the average value calculating unit 212. Here, if the output of the average value calculation means 212 is large, the frame difference data is regarded as the motion component of the video signal and the feedback coefficient a in the attenuation means 38 is made small, so that the amount of feedback of the signal of the motion component is made small. To suppress the deterioration of moving images. On the other hand, when the output of the average value calculating means 212 is small, the frame difference data is regarded as a noise component and the feedback coefficient a is increased by the attenuating means 38, that is, the feedback amount of noise is increased and the noise removing effect is increased. To do.

Further, the second control means 214 operates the feedback coefficient a generated based on the output of the amplitude value calculation means 202 of the signal amplitude detection means 41. When the amplitude value output by the amplitude value calculating means 202 is large, for example, it is considered that a fine pattern is displayed, and the feedback coefficient a in the attenuating means 38 is reduced to deteriorate the image quality of the video signal having the fine pattern. The noise removal amount is suppressed by reducing the feedback amount of noise so as to suppress. On the other hand, the amplitude value calculation means 2
When the amplitude value output by 02 is small, for example, it is considered that a smooth pattern is displayed, and the feedback coefficient a is increased by the attenuation means 38, that is, the feedback amount of noise is increased.
Increases the noise removal effect for video signals with a smooth pattern.

Here, an example of the input / output relationship in the second control means 214 is shown in FIG. FIG. 14 is an input / output characteristic diagram of the second control means 214, and an average value calculation means 212.
And the relationship between the feedback coefficient in the damping means 38 and
The manner in which the input / output characteristics are changed by the output of the amplitude value calculation means 202 is shown.

Finally, the second subtraction means 39 subtracts the data extracted as noise from the input video signal to obtain a noise-free video signal with little deterioration of the moving image at the output terminal 20. be able to.

As described above, according to the second embodiment, the input terminal 10 to which the video signal is added and the frame for delaying the output of the second subtraction means by N frames (N = 1, 2 ...). The delay means 11 and the first subtraction means 12 for taking the difference between the input video signal and the output signal from the frame delay means 11.
, Serial-parallel conversion means 13 for converting the temporally serial frame difference data into data of temporally parallel pixel blocks, orthogonal conversion means 14 for performing orthogonal conversion, and non-linear for the orthogonally converted data. Non-linear processing means 15_1 to 15_k for performing processing, orthogonal inverse transformation means 16 for performing inverse orthogonal transformation on the non-linearly processed data, and data of pixel blocks that are temporally parallel to the inversely-transformed data. After being converted into temporally serial data, parallel-serial conversion means 17 for averaging overlapping data among a plurality of blocks, and attenuation means 18 for multiplying the temporally serialized data by a feedback coefficient, Second subtraction means 19 for subtracting the extracted noise component from the input video signal, signal amplitude detection means 41 for detecting the signal amplitude of the input video signal, and non-linear processing By including the adaptive control means 42 for controlling the threshold values of the means 15_1 to 15_k and the feedback coefficient in the attenuation means 18 according to the input signal amplitude and the frame difference signal, the moving image can be moved in a state where the deterioration of the moving image is small. It is possible to effectively remove noise components in both the area and the stationary area.

The input / output relationship in the first control means 213 and the input / output characteristics in the second control means 214 are not limited to those shown in FIGS. 13 and 14.

The third embodiment of the present invention will be described below with reference to the drawings. FIG. 15 shows a block diagram of a noise removing apparatus according to a third embodiment of the present invention. In the present embodiment, those having the same configurations and functions as those of the elements of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 61 is a signal identifying means, and 62 is an adaptive control means, which will be described in detail later. Reference numeral 63 is an external signal identification code input to which an identification code for identifying an input video signal is input.

The signal identifying means 61 identifies the type of the input video signal. The video signal input to the input terminal 10 is, for example, NTSC (National TV System Committ).
ee) signal, MUSE (Multiple Sub-Nyquist)
Sampling Encoding) signal. Also, for example, a plurality of different video signals (color signal, luminance signal, etc.) may be input in one horizontal display period. Therefore, the signal identifying means 61 identifies the type of the input video signal,
An identification code corresponding to the type of video signal is output. For example, when the NTSC signal is input as the video signal, the identification code is set to "0", and when the color signal of the MUSE signal is input, the identification code is set to "1".
If the brightness signal of the SE signal is input, enter the identification code
Output as 2 ".

The adaptive control means 62 is a serial / parallel conversion means 1
3, signal identifying means 61, non-linear processing means 15_1-15
_K, connected to the damping means 18. Here, a configuration example of the adaptive control means 62 will be described. FIG. 16 is a block diagram of the adaptive control means 62. Reference numeral 301 denotes an absolute value calculation means, which is connected to the serial / parallel conversion means 13 and which has undergone serial / parallel conversion k.
The absolute value of the data of each (k = m × n) pixel block is calculated. An average value calculating unit 302 is connected to the absolute value calculating unit 301 and calculates an average value of k pieces of data of the pixel block calculated by the absolute value calculating unit 301.

Reference numeral 303 denotes an initial value storage means in which a plurality of initial values for a first control means 305 and a second control means 306, which will be described later, are set. Reference numeral 304 denotes an initial value selection means, which is connected to the initial value storage means 303 and which is provided with the signal identification means 6
In accordance with the identification code of the input video signal output by 1 or the identification code of the input video signal externally designated by the external identification code input 63, one initial value from a plurality of initial values set in the initial value storage means 303 To select a first control means 305 and a second control means 3 which will be described later.
It outputs to 06.

Reference numeral 305 denotes a first control means, which is an average value calculation means 302, an initial value selection means 304, and a non-linear processing means 15.
The thresholds for nonlinear processing of the nonlinear processing means 15_1 to 15_k are controlled based on the initial value output from the initial value selection means 304 and the absolute value average value output from the average value calculation means 302, which are connected to the first to 15_k. To do. 306
Is a second control means, which is connected to the average value calculating means 302, the initial value selecting means 304, and the attenuating means 58, and the initial value output by the initial value selecting means 304 and the absolute value average value output by the average value calculating means 302. The feedback coefficient a in the damping means 18 is controlled based on

The operation of the noise eliminator of the third embodiment configured as described above will be described below by comparing its operation with that of the first embodiment. An input video signal containing noise is added to the input terminal 10, the first subtraction means 12 calculates the difference between the input video signal and the output signal of the frame delay means 11, and the serial / parallel conversion means 13 performs temporal parallel processing. The operation up to the point where the pixel block data composed of m × n data is generated and the m × n Hadamard transform is performed by the orthogonal transform means 14 is the same as in the first embodiment.

In the first embodiment, the signal level detecting means 2
Although the adaptive control means 22 is controlled by using 1, the signal identification means 61 and the external identification code input 6 are used in the third embodiment.
3 is used to control the adaptive control means 62.

The operations of the signal identifying means 61, the adaptive control means 62, and the non-linear processing means 15_1 to 15_k are shown in FIG.
Will be explained. The absolute value calculation means 301 of the adaptive control means 62 calculates the absolute value of the data of the 4 × 2 pixel blocks that are temporally parallelized of the frame difference signal. Next, for the calculated absolute value, average value calculation means 302
Then, the average value is calculated. This average value is regarded as the amount of movement of the pixel block portion on the screen.

First, the first control means 305 of the adaptive control means 62 sets an initial value based on the initial value output by the initial value selection means 304. The initial value is, for example, the maximum value of the threshold value output to the non-linear processing means 15_1 to 15_k,
It is a minimum value or a correlation coefficient between a value output by the average value calculation means 302 and a threshold value.

Next, the first control means 305, based on the output of the average value calculation means 302, the non-linear processing means 15_1.
The threshold for non-linear processing is generated for the data of the pixel block consisting of eight components y _{00 to} y ₁₃ in ˜15_k. Here, if the output of the average value calculation unit 302 is large, the frame difference data is regarded as the motion component of the video signal and the threshold value in the non-linear processing units 15_1 to 15_k is reduced to reduce the feedback amount of the signal of the motion component. Make it smaller to prevent deterioration of moving images. On the other hand, if the output of the average value calculating means 302 is small, the frame difference data is regarded as a noise component and the thresholds in the nonlinear processing means 15_1 to 15_k are increased, that is, the amount of noise feedback is increased, and the noise removal effect is increased. To increase.

Here, an example of the input / output relation in the first control means 305 is shown in FIG. FIG. 17 is an input / output characteristic diagram of the first control means 305. The average value calculation means 302
And the thresholds of the non-linear processing means 15_1 to 15_k are shown, and the initial value selecting means 30 is indicated by the identification code.
4 shows how the input / output characteristics change depending on the initial value output from the circuit 4.

Orthogonal transformation means 16 and parallel-serial transformation means 17
The operation of is similar to that of the first embodiment. Then, the parallel-serial converted data is multiplied by the feedback coefficient generated by the adaptive control means 62 in the attenuation means 18.

Signal identifying means 61, adaptive control means 62,
The operation of the damping means 18 will be described with reference to FIG. The operations of the absolute value calculation means 301, the average value calculation means 302, the initial value storage means 303, and the initial value selection means 304 are exactly the same as those described above.

Second control means 306 of adaptive control means 62
Performs initial value setting based on the initial value output by the initial value selection means 304. The initial value is, for example, the damping means 1
The maximum and minimum values of the feedback coefficient output to 8 and the correlation coefficient between the value output from the average value calculating means 302 and the feedback coefficient.

Next, the second control means 306 causes the attenuation means 58 to generate a gain, that is, a feedback coefficient a (0≤a <1), based on the output of the average value calculation means 302. Here, if the output of the average value calculation means 302 is large, the frame difference data is regarded as the motion component of the video signal and the feedback coefficient a in the attenuation means 58 is made small, so that the feedback amount of the signal of the motion component is made small. To suppress the deterioration of moving images. On the other hand, when the output of the average value calculating means 302 is small, the frame difference data is regarded as a noise component and the feedback coefficient a is increased by the attenuating means 58, that is, the feedback amount of noise is increased and the noise removal effect is increased. To do.

Here, an example of the input / output relationship in the second control means 306 is shown in FIG. FIG. 18 is an input / output characteristic diagram of the second control means 306. The average value calculation means 302
And the relationship between the feedback coefficient in the damping means 18 and
The manner in which the input / output characteristics change depending on the initial value output by the initial value selection unit 304 according to the identification code is shown.

Finally, the second subtraction means 19 subtracts the data extracted as noise from the input video signal to obtain at the output terminal 20 a noise-free video signal with little deterioration of the moving image. be able to.

As described above, according to the third embodiment, the input terminal 10 to which the video signal is added and the frame for delaying the output of the second subtracting means by N frames (N = 1, 2 ...). The delay means 11 and the first subtraction means 12 for taking the difference between the input video signal and the output signal from the frame delay means 11.
, Serial-parallel conversion means 13 for converting the temporally serial frame difference data into data of temporally parallel pixel blocks, orthogonal conversion means 14 for performing orthogonal conversion, and non-linear for the orthogonally converted data. Non-linear processing means 15_1 to 15_k for performing processing, orthogonal inverse transformation means 16 for performing inverse orthogonal transformation on the non-linearly processed data, and data of pixel blocks that are temporally parallel to the inversely-transformed data. After being converted into temporally serial data, parallel-serial conversion means 17 for averaging overlapping data among a plurality of blocks, and attenuation means 18 for multiplying the temporally serialized data by a feedback coefficient, Second subtracting means 19 for subtracting the extracted noise component from the input video signal, signal identifying means 61 for identifying the type of the input video signal,
By providing the thresholds of the non-linear processing means 15_1 to 15_k and the feedback coefficient in the attenuation means 58 with the input identification code and the adaptive control means 62 for controlling according to the frame difference signal, the deterioration of the moving image is small. , The noise component in both the moving region and the stationary region can be effectively removed.

The input / output relationship in the first control means 305 and the input / output characteristics in the second control means 306 are not limited to those shown in FIGS.

Furthermore, the noise eliminating device having a configuration in which a plurality of examples of the first, second and third embodiments described above are combined can obtain a further excellent noise eliminating effect. Needless to say.

[0096]

As described above, according to the noise eliminator of the present invention, the parameters for noise component extraction such as the threshold of the non-linear processing and the feedback coefficient are set to the signal level of the input video signal or the signal amplitude or the signal. Depending on the type
In addition, since the adaptive control is performed according to the value of the noise component, it is possible to effectively remove the noise component in both the moving region and the still region while the deterioration of the moving region image is small.

[Brief description of drawings]

FIG. 1 is a block diagram of a noise canceller according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an example of serial-parallel conversion means.

FIG. 3 is a block diagram showing an example of parallel-serial conversion means.

FIG. 4 is a block diagram showing an example of signal level detection means.

FIG. 5 is a block diagram showing an example of adaptive control means 22.

FIG. 6 is a block diagram of a pixel block

FIG. 7 is an input / output characteristic diagram of the non-linear processing means.

FIG. 8 is an input / output characteristic diagram of the first control means 143.

FIG. 9 is an input / output characteristic diagram of the second control means 144.

FIG. 10 is a configuration diagram of a noise removing device according to a second embodiment of the present invention.

FIG. 11 is a block diagram showing an example of signal amplitude detection means.

FIG. 12 is a block diagram showing an example of adaptive control means 42.

FIG. 13 is an input / output characteristic diagram of the first control means 213.

FIG. 14 is an input / output characteristic diagram of the second control means 214.

FIG. 15 is a block diagram of a noise canceller according to a third embodiment of the present invention.

FIG. 16 is a block diagram of adaptive control means 62.

FIG. 17 is an input / output characteristic diagram of the first control means 305.

FIG. 18 is an input / output characteristic diagram of the second control means 306.

FIG. 19 is a block diagram of a conventional noise eliminator.

FIG. 20 is an input / output characteristic diagram of a non-linear processing unit of a conventional example.

[Explanation of Codes] 10 Input Terminals 11 Frame Delay Means 12 First Subtracting Means 13 Serial / Parallel Converting Means 14 Orthogonal Transforming Means 15_1 to 15_k Nonlinear Processing Means 16 Orthogonal Inverse Transforming Means 17 Parallel / Serial Converting Means 18 Attenuating Means 19 Second Subtraction means 20 Output terminal 21 Signal level detection means 22 Adaptive control means 41 Signal amplitude detection means 42 Adaptive control means 61 Signal identification means 62 Adaptive control means 63 External signal identification code input 101-106, 111-116 1 sample delay means 107, 117 line delay means 118-124 adder means 125 attenuator means 131, 201 serial-parallel converter means 132 average value calculation means 141, 211, 301 absolute value calculation means 142, 212, 302 average value calculation means 143, 213 first control means 144, 214 Second system Means 202 amplitude value calculating means 303 initial value storage unit 304 the initial value selecting unit 305 first control means 306 second control means

Claims (6)

[Claims] 1. A delay means for delaying a signal in response to an input video signal, a first subtraction means for obtaining a differential signal between the input video signal and an output signal of the delay means, and the first subtraction means. Orthogonal transformation means for performing orthogonal transformation on the obtained difference signal, non-linear processing means for performing non-linear processing on the output of the orthogonal transformation means, and the orthogonal transformation for the output of the non-linear processing means Means for performing an orthogonal inverse transform which is an inverse transform to the orthogonal transform in the means, an attenuating means for attenuating the output of the orthogonal inverse transforming means, and a differential signal between the input video signal and the output signal of the attenuating means. Second subtraction means for obtaining the signal level, signal level detection means for detecting the signal level of the input video signal, and the nonlinear processing procedure based on the output of the signal level detection means and the output of the first subtraction means. And an adaptive control means for adaptively controlling at least one of the threshold of the non-linear processing and the attenuation amount in the attenuating means, the output signal of the second subtracting means being delayed by the delaying means, A noise removing device, wherein the output signal of the subtracting means is taken out as a signal from which noise has been removed. 2. The adaptive control means comprises m sample points in the horizontal direction,
Absolute value / average value calculating means for calculating the average value of the absolute values of the data of the pixel block consisting of n lines in the vertical direction (m and n are natural numbers), the output of the signal level detecting means and the above First control means for controlling the threshold value of the non-linear processing in the non-linear processing means based on the output of the absolute value / average value calculation means, the output of the signal level detection means and the output of the mean value calculation means A second control means for controlling the amount of attenuation of the attenuation means.
The noise removal device described. 3. A delay means for delaying a signal in response to an input video signal, a first subtraction means for obtaining a difference signal between the input video signal and an output signal of the delay means, and the first subtraction means. Orthogonal transformation means for performing orthogonal transformation on the obtained difference signal, non-linear processing means for performing non-linear processing on the output of the orthogonal transformation means, and the orthogonal transformation for the output of the non-linear processing means Means for performing an orthogonal inverse transform which is an inverse transform to the orthogonal transform in the means, an attenuating means for attenuating the output of the orthogonal inverse transforming means, and a differential signal between the input video signal and the output signal of the attenuating means. Second subtraction means for obtaining the signal amplitude, signal amplitude detection means for detecting the signal amplitude of the input video signal, and the nonlinear processing means based on the output of the signal amplitude detection means and the output of the first subtraction means. The adaptive control means for adaptively controlling at least one of the threshold of the non-linear processing and the attenuation amount in the attenuating means, the output signal of the second subtracting means is delayed by the delaying means, and the second A noise removing device, wherein the output signal of the subtracting means is taken out as a signal from which noise has been removed. 4. The adaptive control means comprises m sample points in the horizontal direction,
Absolute value / average value calculating means for obtaining an average value of absolute values of pixel block data consisting of n lines in the vertical direction (m and n are natural numbers), the output of the signal amplitude detecting means, and the above First control means for controlling the threshold value of the non-linear processing in the non-linear processing means based on the output of the absolute value / average value calculating means, the output of the signal amplitude detecting means and the output of the absolute value / average value calculating means. The noise removing device according to claim 1, further comprising second control means for controlling an attenuation amount of the attenuation means based on the second control means. 5. A delay means for delaying a signal in response to an input video signal, a first subtraction means for obtaining a difference signal between the input video signal and an output signal of the delay means, and the first subtraction means. Orthogonal transformation means for performing orthogonal transformation on the obtained difference signal, non-linear processing means for performing non-linear processing on the output of the orthogonal transformation means, and the orthogonal transformation for the output of the non-linear processing means Means for performing an orthogonal inverse transform, which is an inverse transform to the orthogonal transform in the means, an attenuating means for attenuating the output of the orthogonal inverse transforming means, and a difference signal between the input video signal and the output signal of the attenuating means. A second subtracting means for obtaining the signal, a signal identifying means for identifying the signal type of the input video signal, and a non-linear processing means based on the output of the signal identifying means and the output of the first subtracting means. Adaptive processing means for adaptively controlling at least one of the threshold value of the shape processing and the attenuation amount in the attenuation means, the output signal of the second subtraction means is delayed by the delay means, and the second subtraction is performed. A noise eliminating device, wherein the output signal of the means is taken out as a signal from which noise has been eliminated. 6. The adaptive control means comprises m sample points in the horizontal direction,
Absolute value / average value calculating means for obtaining the absolute value of the data of the pixel block consisting of n lines in the vertical direction (m and n are natural numbers), and an initial value storage in which a plurality of initial values are set Means, an initial value selection means for selecting one initial value from the initial value storage means using a signal identification code output from the signal identification means or a signal identification code input from the outside, and the absolute value / average value. First control means for controlling the threshold value of the non-linear processing in the non-linear processing means based on the output of the calculating means and the output of the initial value selecting means, the output of the absolute value / average value calculating means and the initial value selecting means 6. The noise removing device according to claim 5, further comprising a second control unit that controls the amount of attenuation of the attenuation unit based on the output of the.