JP3308705B2 - Impulse noise elimination circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impulse noise elimination circuit suitable for a satellite broadcast receiving apparatus and the like, and more particularly to an improvement of an impulse noise elimination circuit for performing an erroneous detection reduction operation by motion detection.

[0002]

2. Description of the Related Art Since the radio waves of satellite broadcasting are microwaves, when the reception level decreases due to rainfall or snow on an antenna, the C / N (carrier / noise) of the reception signal decreases. As the C / N decreases, the S / N (signal / noise) of the video signal after FM demodulation decreases. Further, when the C / N decreases and exceeds the threshold value, medaka noise This generates impulse noise called.

FIG. 5 shows a waveform of an impulse noise generated in a video signal. For a video signal A whose luminance changes stepwise as shown in FIG.
N decreases and impulse noise B occurs. When this impulse noise is generated, the brightness rises or falls significantly over several hundred nanoseconds. When this is viewed on a monitor screen, it looks like a white or black medaka, and the quality of the image is greatly impaired. In order to remove such impulse noise, the present applicant has previously disclosed Japanese Patent Application Laid-Open No. Hei 4-3614.
No. 81 has proposed a noise elimination circuit having a configuration as disclosed.

FIG. 6 is a block diagram showing a television receiver including such a noise elimination circuit. A reception signal received by the antenna 1 is transmitted to the LNB 2 by the first I / O.
The frequency is converted to an F signal 3 and sent to the tuner 4. The tuner 4 selects a desired channel and performs FM demodulation.
The tuner 4 outputs a video signal 5, a detection signal 7, and an audio signal 11. The detection signal 7 is a signal immediately after the FM demodulation. After the detection signal 7 is de-emphasized, the 15 Hz triangular wave is removed, and the L signal of the video signal band is removed.
The video signal 5 is sent through the PF. The noise reduction circuit 6 detects and removes impulse noise.

Before detecting impulse noise, the noise reduction circuit 6 may erroneously detect (erroneously detect) a part that is not impulse noise as impulse noise. Is performed, the image quality of that part is impaired. Therefore, the probability of occurrence of erroneous detection must be sufficiently smaller than the probability of occurrence of impulse noise. When a C / N (for example, 6 dB or more) in which no impulse noise is generated is obtained, it is necessary to prohibit noise removal in the noise reduction circuit 6.

To this end, a noise detection circuit 8 is provided,
C / N is detected. The noise detection circuit 8 detects only a noise component included in the detection signal 7 and obtains a voltage corresponding to a noise level (for example, about 1 to 2 V). N
Is determined, and the result of the determination is output to the noise reduction circuit 6 as a noise reduction control signal 9. When the control signal 9 indicates that C / N at which impulse noise occurs, the noise reduction circuit 6 detects an impulse noise portion in the video signal and performs interpolation processing on the luminance of the portion to perform noise reduction. It is supplied to the monitor 12 as a video signal 10.
Further, when the control signal 9 is C
/ N, the video signal 5 from the tuner 4 is supplied to the monitor 12 without interpolation. On the other hand, the audio signal from the tuner 4 is transmitted to the monitor 1 in the same manner as in the prior art.
Feed to 2.

FIG. 7 is a block diagram showing a schematic configuration of the noise reduction circuit 6, and FIG.
FIG. 3 is a block diagram showing a specific configuration of the embodiment. In FIG.
The video signal 5 FM-demodulated from the tuner 4 is A / D-converted by an A / D converter 13 at a sampling frequency of 4 fsc (about 14.318 MHz), and a luminance signal (Y signal) and a chroma signal are output by a YC separation circuit 14. (C signal). The Y signal is applied to an impulse noise detection circuit 6-1. Impulse noise is detected based on the Y signal. According to the detection result, the noise interpolation circuits 6-2 and 6-3 convert the Y signal and the C signal. The pixels for which noise has been detected are interpolated with adjacent pixels that do not contain noise. The interpolated Y and C signals are mixed by a YC mix circuit 39 and D /
The data is D / A converted by the A conversion circuit 40 and output.

In FIG. 9, reference numeral 13 denotes an A / D converter;
Is a YC separation circuit, 15 is a luminance signal, 16-1 to 16-4
Is a line memory, 17 is a 1H delayed luminance signal, 18 is 2H
Delayed luminance signal, 19 is a frame memory, 20 is a frame delayed luminance signal, 21 to 23 are difference signals, 24-1 to 24-
3 is an absolute value circuit, 25-1 to 25-3 are comparison circuits, 26
Is a threshold, 27 is a 3-input AND circuit, 28 is an impulse noise detection signal, 29 is an interpolation luminance signal, 30 and 31 are switches, 32 is a chroma signal, 33 is a 1H delay chroma signal, 34 is a 2H delay chroma signal, 35 is a phase inversion circuit,
36 is an interpolation chroma signal, 37 and 38 are switches, 39 is a YC mix circuit, 40 is a D / A converter, and 41-1 to 4-4.
1-3 is a subtractor, 42-1 to 42-2 are adders, 43-
1 to 43-2 are 1/2 multipliers.

In FIG. 9, after a video signal 5 from a tuner 4 passes through an A / D converter 13, a YC separation circuit 14
To separate them into a luminance signal 15 and a chroma signal 32 and supply them to the line memories 16-1 to 16-4, respectively. And
1H and 2H delayed luminance signals 17 and 18 are obtained from the line memories 16-1 to 16-2, respectively. On the other hand, 1H and 2H chroma signals 33 and 34 are obtained from the line memories 16-3 to 16-4, respectively. Also, 1H delayed luminance signal 1
7 is passed through a frame memory 19 to obtain a frame delay luminance signal 20.

Next, from the 1H delayed luminance signal n (0) 17 to the 2H delayed luminance signal n (A) 18, the luminance signal n (B)
15 and the frame delayed luminance signal n (C) 20 are subtracted by subtractors 41-1 to 41-3, respectively, and the difference signal between them is
That is, the n (0) -n (C) signal 23 is calculated, and the difference signal between them is passed through the absolute value circuits 24-1 to 24-3 to obtain the absolute values, and the comparison circuits 25-1 to 25-3 are respectively obtained. Is used to determine the magnitude of the threshold value 26, and the result is input to a three-input AND
What is obtained by inputting to the circuit 27 is an impulse noise detection signal 28. Here, the threshold value 26 is set to an optimum value through experiments.

When the impulse noise is detected, an operation for replacing the detected portion with some signal, that is, an interpolation is required. Therefore, in the embodiment of FIG. 9, the luminance signal 15 and the 2H delayed luminance signal 18 are added to the adders 42-1, 1,
The signal is passed through a / 2 multiplier 43-1 to perform interpolation based on the average value of these signals, and these are input to the switch 30 as an interpolated luminance signal 29. The switch 30 selects the 1H-delayed luminance signal 17 and the interpolated luminance signal 29 based on the impulse noise detection signal 28 output from the AND circuit 27.
Output. The switch 31 selects the 1H-delayed luminance signal 17 in the C / N where no impulse noise occurs, and controls the noise reduction control signal 9 to select the output of the switch 30 in the C / N where the impulse noise occurs. .

For the chroma signal 32, when impulse noise is detected, it is necessary to perform interpolation. Therefore, the chroma signal 32 and the 2H-delayed chroma signal 34 are passed through adders 42-2 and 1-2 multiplier 43-2 to obtain an average value of the signals, and the average value is inverted by a phase inversion circuit 35. Thus, an interpolation chroma signal 36 is obtained, and this signal 36 and the 1H-delayed chroma signal 33 are input to switches 37 and 38. The switch 37 operating in synchronization with the switch 30 selects and outputs the signal by the impulse noise detection signal 28. . The switch 38 is synchronized with the switch 31 and operates in exactly the same manner.

Here, the reason why the phase of the interpolation chroma signal 36 is inverted by the phase inversion circuit 35 is as follows in the NTSC system.
This is because the chroma signal has the same phase as the 1H delayed chroma signal 33 because the phase of the chroma signal is inverted every line. The outputs of switches 31 and 38 are
After being composited by the mix circuit 39, it is converted into an analog signal by the D / A converter 40, and the noise reduction video signal 10
Output as

According to such an impulse noise detection method, erroneous detection can be almost completely prevented in a still image. By the way, such an impulse noise detection method is a kind of noise extraction using a filter.
If the frequency domain extracted by this filter is shown on the vertical-time frequency axis, it is the domain of FIG. However, if this noise detection method is applied, an erroneous detection is performed on the image signal in the frequency domain indicated by the hatched portion in FIG. If interpolation is performed by using adjacent pixels for this erroneous detection, the portion will be distorted and image quality will be degraded.

The present applicant has further disclosed in Japanese Patent Application Laid-Open No. 5-145802 as an impulse noise elimination circuit which has improved image quality by preventing image distortion due to erroneous detection of impulse noise in a specific frequency region in a moving image. An arrangement as disclosed was provided.

In order to prevent erroneous detection of impulse noise in a moving image, motion of a pixel is detected in the time-frequency region of the hatched portion in FIG. 8 where the erroneous detection occurs, and the detected pixel is a candidate for impulse noise. It becomes possible by removing it from. However, motion detection based on frame correlation of one pixel, which is usually performed, is exactly the same as the above-described method of detecting impulse noise, and is unsuitable because the motion of noise cannot be determined. Therefore, the impulse noise detection circuit of the above publication employs a motion detection method as described below.

FIG. 10 shows the motion detection method.
Considered as one block of three pixels of the combined upper and lower pixels S ₁₀ and S ₁₂ for pixels S ₁₁ of interest, S ₁₀ and S ₁₂
If a motion is detected in any one of the pixels S ₁₁
Is determined to have occurred. Motion detection pixel S ₁₀ and S ₁₂ performs the level comparison of each 1-frame previous pixel S _20, S _22, performed by the magnitude of the level difference and the threshold value. That is, if the threshold for motion detection is R ₂ ,
If the condition of | S ₁₀ −S ₂₀ |> R ₂ or | S ₁₂ −S ₂₂ |> R ₂ is satisfied, it is determined that there is a movement in S _11, and is excluded from the impulse noise candidates.

[0018] Figure 11 shows a basic configuration for implementing the motion detection method described above, 200 pixels S _12, 2
01 is S ₁₁ , 202 is S ₁₀ , 203-1 to 203-4 are line memories, 204 is a frame memory, 205 is S ₂₂ , 206 is S ₂₁ , 207 is S ₂₀ , 208 is a 1H previous motion detection signal, 209 is a motion detection signal after 1H, 210
Is a motion detection signal, 211 is an OR circuit, 212-1, 21
2-2 is a frame correlation determination circuit.

S ₁₂ (200) is the line memory 203-1
And the line memory 2
S ₁₁ (201) is obtained from the 03-1, S ₁₀ (202) through a line memory 203-2 is output. S ₂₂ (205) is output from the frame memory 204, S ₂₁ (206) is obtained by the line memory 203-3, and S ₂₀ (20) is further transmitted through the line memory 203-4.
7) is output.

The frame correlation judgment circuit 212-1 calculates | S ₁₀
−S ₂₀ |> R ₂ and S 1H before S ₁₁ (201)
₁₀ Performs motion detection on (202) and outputs a 1H previous motion detection signal 208. Also, a frame correlation determination circuit 2
12-2 determines | S ₁₂ −S ₂₂ | to detect the motion of S ₁₂ (200) 1H after S ₁₁ (201), and
The post-H motion detection signal 209 is output. The 1H front motion detection signal 208 and the 1H post motion detection signal 209 are
Is ORed, and a motion detection signal 210 is obtained. FIG. 12 shows an embodiment based on such a principle. A portion shown by a broken line is an impulse noise detection unit similar to that of FIG. 9, and a portion shown by a dashed line is an added motion detection unit.

Next, the operation of the motion detecting section shown in FIG. 12 will be described. The luminance signal (Y) 100 from the Y / C separation circuit 14 is input to a frame memory 101 and an adder 115, and the difference between the luminance signal (Y) 100 and the frame delayed luminance signal 102 delayed by one frame period is calculated by the frame memory 101. The frame difference signal 105 is extracted via the value circuit 104. The level of the frame difference signal 105 is compared with the level of a threshold signal 107 for motion detection by a comparison circuit 106, and a motion detection signal 108 after 1H is obtained according to the level thereof, and the 1H signal is obtained via line memories 109-1 and 109-2. A pre-motion signal 110 is obtained, both signals are input to a NOR circuit 111, and a motion detection signal 112 is output.

The motion detection signal 112 becomes L level when a motion is detected, and becomes H level when no motion is detected. The impulse noise candidate signal (the impulse noise detection signal) becomes H level when it is determined that the impulse noise candidate signal is an impulse noise candidate.
And the impulse noise detection signal 120 output from the AND circuit 113 to which the impulse noise detection signal 120 is input.
14 is excluded from the candidates of the impulse noise when a motion is detected, and is regarded as having no impulse noise component. In this way, the corresponding pixel is excluded from the candidates of the impulse noise in response to the motion detection, and erroneous detection of the impulse noise of the moving image can be reduced.

[0023]

However, in the conventional impulse noise detection circuit which reduces the erroneous detection of the impulse noise in the moving image by excluding the corresponding pixel from the candidates of the impulse noise in response to the motion detection, C / C When N greatly decreases and the amount of generation of impulse noise increases to a certain degree or more, there is a problem that the image quality improvement effect is reduced rather than performing an erroneous detection reduction operation by motion detection.

FIG. 4 is a characteristic diagram for explaining the situation clarified by the present applicant. The vertical axis indicates the impulse noise occurrence probability after noise removal, and the horizontal axis indicates the impulse noise occurrence probability Pi. . P _x1 indicates a noise characteristic obtained when the false detection reduction operation by the motion detection is not performed, and P _x2 indicates a noise characteristic obtained when the false detection reduction operation by the motion detection is performed as shown in Japanese Patent Application Laid-Open No. 5-145802. The obtained noise characteristics are shown. As is clear from FIG.
It can be understood that the noise removal effect of both P _x1 and P _x2 decreases as the impulse noise occurrence probability Pi increases, and that the effect of P _x2 is always lower than that of P _x1 . However,
P _x2 suppresses the generation of an error signal in the motion area in the image after the impulse noise removal.

The impulse noise occurrence probability P
i depends on C / N in satellite broadcasting. That is, Pi becomes larger as C / N becomes lower. However, when observing the image after the impulse noise removal, when Pi becomes larger than a certain value, it is better not to perform the false detection reduction operation by motion detection. It was found that the image improvement effect was improved. This is because the difference between P _x1 and P _x2 is smaller than the amount of erroneous detection distortion suppressed by the erroneous detection reduction operation when Pi exceeds a certain value from the relationship “P _x2 > P _x1 ” in FIG. It is thought that it becomes big.

The present invention has been made on the basis of the above principle. In order to reduce erroneous detection of impulse noise in a moving image by excluding the corresponding pixel from candidates for impulse noise in response to motion detection, When the C / N is significantly reduced and the amount of generation of impulse noise is increased to a certain degree or more, an impulse noise elimination circuit that inhibits a false detection reduction operation by motion detection and prevents a reduction in image quality improvement effect. The purpose is to provide.

[0027]

According to a first aspect of the present invention, there is provided a demodulation apparatus for demodulating a reception signal modulated from a reception antenna to obtain a video signal including a detection signal and luminance information. Means for detecting a noise component included in the detection signal, and determining the presence or absence of a single-shot impulse noise component having a large luminance change included in the video signal based on the amount of the noise component; When a noise component amount exceeds a second predetermined amount that is greater than the predetermined amount, a first determination signal used for determining whether or not to perform an impulse noise removal operation is output. A noise detection determination unit that outputs a second determination signal used for determining whether to perform the false detection reduction operation; and the first determination signal, when the impulse noise component is present, Detecting an impulse portion in the image signal, interpolating the luminance of the detected portion to output a video signal from which the impulse noise portion has been removed, and outputting the video signal from the demodulation means when there is no impulse noise component. Noise detection and removal means, a frame difference component extraction means for extracting a frame difference component signal from a video signal containing the luminance signal and a signal obtained by delaying the signal for a predetermined frame period, Compare the level with the signal, based on the comparison result, detect the presence or absence of motion in the upper and lower adjacent pixels in the same field,
The motion detection means for outputting a motion detection signal, and the motion detection means, only when there is motion detection, it is considered that there is no impulse noise component, and the output of the noise detection removal means Impulse noise determining means for only the video signal from the demodulating means, and prohibiting means for prohibiting output of the motion detection signal from the motion detecting means when a second determination signal is output from the noise detection determining means, It is characterized by having.

[0028]

According to the first aspect of the present invention, a noise component included in a detection signal obtained from a received signal is detected, and a first determination signal and a second determination signal are detected based on the amount of the noise component. A signal is output. According to the first determination signal,
When there is the impulse noise component, an impulse part in the video signal is detected, and the luminance of the detected part is interpolated to output a video signal from which the impulse noise part has been removed. When there is no impulse noise component,
The video signal is output. The level of a frame difference component signal extracted from a video signal including the luminance information and a signal obtained by delaying this signal for a predetermined frame period is compared with the level of a predetermined reference signal. Based on the comparison result, a motion signal is output which detects the presence or absence of motion at the upper and lower adjacent pixels in the same field. Only when a motion is detected by this motion detection signal, it is regarded that there is no impulse noise component, and only the video signal is output. When the second determination signal is output, the output of the motion detection signal is prohibited even if there is a motion detection signal based on the motion detection signal.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing a television receiver including an impulse noise elimination circuit according to the present invention. 1
Is an antenna, 2 is an intermediate frequency conversion circuit (LNB), 3 is a first IF signal, 4 is a tuner, 5 is a video signal, 6 is a noise reduction circuit which is a means for detecting and removing impulse noise, 7 is a detection signal, and 8 is a detection signal. Detection of impulse noise
9 is a noise reduction control signal (first determination signal); 150 is an erroneous detection protection control signal (second determination signal); 10 is a noise reduction video signal; 11 is an audio signal; Is a monitor.

In the present embodiment, the noise detection circuit 8 for detecting a noise component included in the detection signal 7 is used for determining whether or not to perform an impulse noise removal operation when the amount of the noise component exceeds a predetermined value. Outputs the reduction control signal 9 and, when the noise component amount exceeds a second predetermined amount larger than the predetermined amount, an erroneous detection protection control signal 150 used for determining whether or not to perform an erroneous detection reduction operation by motion detection. Is output. FIG. 3 is a block diagram showing a specific configuration of the noise detection circuit 8, where 151 is a noise BPF (band pass filter), 152 is a noise detection circuit, and 153
Is a first comparator, and 154 is a second comparator.

The signal band of the detection signal 7 is about 6 MHz,
All components exceeding 6 MHz are noise. Therefore, a component exceeding 6 MHz is extracted by the noise BPF 151 as a noise component signal, and this noise component signal is output by the noise detection circuit 152 as a DC voltage corresponding to the noise component amount. Then, this DC voltage is compared with a comparison voltage 1 (a voltage used for determining whether or not to perform the impulse noise removal operation) by the first comparator 153, and when the DC voltage exceeds the comparison voltage 1, And outputs a noise reduction control signal 9 used to determine whether or not to perform an impulse noise removal operation. On the other hand, the second comparator 154 compares the DC voltage with a comparison voltage 2 (a voltage used to determine whether or not to use the false detection reduction means by motion detection), and this DC voltage exceeds the comparison voltage 2. In this case, an erroneous detection protection control signal 150 used for determining whether to perform the erroneous detection reduction operation by the motion detection is output.

FIG. 1 is a block diagram showing an embodiment of an impulse noise elimination circuit according to the present invention. The portion shown by a broken line is an impulse noise detecting section similar to that of FIG. 9, and the portion shown by a dashed line is the motion added by the present invention. It is a detection unit. The motion detection unit includes a frame memory 101, an adder 115, an absolute value circuit 104, a comparison circuit 106, and line memories 109-1, 1 and 1.
09-2, a NOR circuit 111, an AND circuit 113, and an erroneous detection protection control switch 155, 102 is a frame delay luminance signal, 105 is a frame difference signal, 107 is a threshold signal for motion detection, and 108 is motion detection after 1H. Signal, 11
0 is a 1H previous motion detection signal, and 112 is a motion detection signal.

In the motion detecting section, the frame memory 101, the adder 115 and the absolute value detecting circuit 104 constitute the frame difference component extracting means. Further, the comparison circuit 106, the line memories 109-1, 109-2 and the NOR circuit 111 constitute the motion detecting means, the AND circuit 113 constitutes the impulse noise judging means, and furthermore, the erroneous detection protection control switch 155. Constitutes the prohibiting means.

The impulse noise detector comprises line memories 116-1, 116-2, 116-3, adders 117-1, 117-2, and comparators 118-1, 11-2.
8-2, 118-3, absolute value circuits 119-1, 119-
2 and an AND circuit 121, and constitutes the noise detection determination means. The noise detection and removal means has the same configuration as the noise interpolation units (Y) and (C) in FIG.

Next, the operation of the embodiment of FIG. 1 will be described. The noise reduction control signal 9 is output from the noise detection circuit 8 of FIGS. 2 and 3 to the noise reduction circuit 6, and if this control signal indicates that C / N at which impulse noise occurs, the noise reduction circuit 6 , An impulse noise portion in the video signal is detected, and the luminance of the portion is subjected to interpolation processing and supplied to the monitor 12 as a noise reduction video signal 10. The control signal 9
Indicates that the C / N does not generate impulse noise, the video signal 5 from the tuner 4 is supplied to the monitor 12 without interpolation. The detailed operation when the noise reduction signal 9 is output from the noise detection circuit 8 to the noise reduction circuit 6 as described above with reference to FIG. 9 will not be described.

On the other hand, when the C / N is significantly reduced and the false detection protection control signal 150 is output from the noise detection circuit 8 to the noise reduction circuit 6, the false detection protection control is performed by the motion detection section of FIG. The switch 155 outputs the signal 15
By being turned off by 0, the motion detection signal 112 output from the NOR circuit 111 is not output to the AND circuit 113. That is, the output of the motion detection signal 112 to the AND circuit 113 is prohibited. As a result, when the C / N is significantly reduced, the false detection reduction operation by the motion detection is prohibited. Note that the detailed operation of the motion detection unit is as described above with reference to FIG.

As described above, according to this embodiment, when the corresponding pixel is excluded from the candidates of the impulse noise in response to the motion detection to reduce the erroneous detection of the impulse noise in the moving image, the C / N is extremely low. When the amount of generation of impulse noise is increased to a certain degree or more, the operation of reducing erroneous detection by motion detection is prohibited, so that it is possible to prevent the image quality improvement effect from being reduced.

[0038]

As described above, according to the present invention, in order to reduce the erroneous detection of impulse noise in a moving image by excluding the corresponding pixel from candidates for impulse noise in response to motion detection, the C / N Is significantly reduced and the amount of generation of impulse noise is increased to a certain degree or more, the erroneous detection reduction operation by the motion detection is prohibited, so that a decrease in the image quality improvement effect can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an impulse noise elimination circuit according to the present invention.

FIG. 2 is a block diagram illustrating a television receiver including an impulse noise removal circuit according to the present invention.

FIG. 3 is a block diagram showing a specific configuration of a noise detection circuit of the impulse noise elimination circuit of the present invention.

FIG. 4 is a noise characteristic diagram illustrating the principle of the present invention.

FIG. 5 is a waveform diagram showing impulse noise generated in a video signal.

FIG. 6 is a block diagram showing a television receiver including a conventional impulse noise removing circuit.

FIG. 7 is a block diagram showing a specific configuration of a conventional noise reduction circuit.

FIG. 8 is a characteristic diagram illustrating a frequency region in which noise is detected.

FIG. 9 is a block diagram showing a specific configuration of a conventional noise reduction circuit.

FIG. 10 is an explanatory diagram of a conventional motion detection method.

FIG. 11 is a specific configuration diagram for implementing a conventional motion detection method.

FIG. 12 is a block diagram showing a specific configuration of a conventional impulse noise removal circuit.

[Explanation of symbols]

 Reference Signs List 6 noise reduction circuit 8 noise detection circuit 101 frame memory 104 absolute value circuit 106 comparison circuit 109-1, 109-2 line memory 111 NOR circuit 113 AND circuit 155 erroneous detection protection control switch

Claims (1)

(57) [Claims] 1. A demodulation means for demodulating a reception signal modulated from a reception antenna to obtain a video signal including a detection signal and luminance information, detecting a noise component included in the detection signal, and calculating an amount of the noise component. It is determined whether or not there is a single-shot impulse noise component having a large change in luminance contained in the video signal based on the first signal. If the noise component amount exceeds a predetermined value, a first impulse noise removal operation is performed. And outputting a second determination signal for use in determining whether to perform an erroneous detection reduction operation by motion detection when the noise component amount exceeds a second predetermined amount that is larger than the predetermined amount. When the impulse noise component is present, the noise detection judging means and the first judgment signal detect the impulse part in the video signal and perform interpolation processing on the luminance of the detected part. A video signal from which an impulse noise portion has been removed, and a noise detection and removal unit that outputs a video signal from the demodulation unit when there is no impulse noise component; a video signal containing the luminance signal; Frame difference component extraction means for extracting a frame difference component signal from the signal delayed for the frame period,
A motion detection unit that compares the level of the frame difference component signal with a predetermined reference signal, detects the presence or absence of motion in upper and lower adjacent pixels in the same field based on the comparison result, and outputs a motion detection signal; Only when there is motion detection by the motion detecting means, it is considered that there is no impulse noise component, and the output of the noise detection removing means is only the video signal from the demodulating means. Impulse noise determining means, comprising: impulse noise determining means; and prohibiting means for prohibiting output of a motion detection signal from the motion detecting means when a second determination signal is output from the noise detection determining means. Elimination circuit.