JP2003008938A - Noise eliminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise eliminating device that can detect a noise quantity even in a multi-screen display so as to eliminate the noise and obtain an image with high image quality. SOLUTION: YC separation circuits 2, 5 receive 1st and 2nd video signals and obtain luminance signals Y1, Y2 and chrominance signals respectively. A multi-screen display circuit 7 obtains an image for multi-screen display from outputs of a chroma demodulation circuits 3, 6. A changeover circuit 8 outputs an output from the chroma demodulation circuit 3 at single image display or outputs an output from the multi-screen display circuit 7 at multi-screen display. A noise detection circuit 12 detects the noise from an output of the changeover circuit 8. On the other hand, a noise detection circuit 23 in the YC separate circuit 2 detects the noise quantity in the luminance signal Y1. Thus, the noise quantity of the 1st video signal can be detected even in the multi-screen display. A microcomputer circuit 24 obtains the noise elimination quantity from the output of the noise detection circuit 12 at the single image display or obtains the noise elimination quantity from an output of the noise detection circuit 23 at the multi-screen display. Thus, the noise of the 1st video signal can be eliminated even in the multi-screen display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise eliminator suitable for a television receiver capable of multi-screen display.

[0002]

2. Description of the Related Art Conventionally, in a television receiver,
A noise eliminator that automatically removes noise is used. In the conventional noise eliminator, in order to provide a high quality image according to the state of the input signal, the S
The noise removal amount is controlled according to / N. The S / N amount of the input signal is detected during the back porch period of the horizontal blanking period of the luminance signal.

FIG. 5 is a block diagram showing a conventional noise eliminator of this type. The circuit of FIG. 5 is applied to a television receiver having a multi-screen display function for displaying a plurality of images divided on the same display screen.

A first video signal is input to the video input terminal 1. This input video signal is supplied to the YC separation circuit 2 and separated into a luminance signal Y1 and a chroma signal. The chroma signal is the two color difference signals C in the chroma demodulation circuit 3.
Demodulated to R1 and CB1. The luminance signal Y1 from the YC separation circuit 2 is output via the chroma demodulation circuit 3 after being delayed by the time required for the color signal demodulation processing of the chroma demodulation circuit 3.

A second video signal is input to the video input terminal 4. The second video signal is supplied to the YC separation circuit 5 and separated into a luminance signal Y2 and a chroma signal. Y / C
The chroma signal from the separation circuit 5 is demodulated in the chroma demodulation circuit 6 into two color difference signals CR2 and CB2. The luminance signal Y2 from the YC separation circuit 5 is output via the chroma demodulation circuit 6 after being delayed by the time required for the color signal demodulation processing of the chroma demodulation circuit 6.

The luminance signal Y1 and the two color difference signals CR1 and CB1 from the chroma demodulation circuit 3 are supplied to the multi-screen display circuit 7 and the switching circuit 8. The luminance signal Y2 and the two color difference signals CR2 and CB2 from the chroma demodulation circuit 6 are supplied to the multi-screen display circuit 7.

The multi-screen display circuit 7 performs processing such as dual screen display. The multi-screen display circuit 7 has a luminance signal Y1 and two color difference signals CR1,
CB1, a luminance signal Y2 and two color difference signals CR2, C
B2 and B2 are horizontally compressed to 1/2. The multi-screen display circuit 7 generates a multi-luminance signal YM for displaying the horizontally compressed luminance signals Y1 and Y2 on the left and right on the display screen, and also generates the horizontally compressed color difference signals CR1 and CR2.
Two multiple color difference signals CRM and CBM for displaying CR2 and color difference signals CB1 and CB2 on the left and right on the display screen.
To generate.

The multiple luminance signal YM and the multiple color difference signals CRM and CBM are supplied to the switching circuit 8. The switching circuit 8 switches between single-screen display and multi-screen display according to a user operation. That is, the switching circuit 8 outputs the luminance signal Y1 and the color difference signals CR1 and CB1 from the chroma demodulation circuit 3 when displaying one screen, and the multiple luminance signal YM and the multiple color difference from the multiple screen display circuit 7 when displaying multiple screens. Signal CR
Outputs M and CBM.

Luminance signal Y selected by the switching circuit 8
The color difference signals CR and CB are supplied to the motion adaptive progressive scan conversion circuit 9. The motion adaptive progressive scan conversion circuit 9 is
It is composed of an automatic noise removal circuit 10 and a progressive scan conversion circuit 13. The multi-screen display circuit 7 and the motion adaptive progressive scan conversion circuit 9 are divided into blocks,
It may be composed of two ICs (integrated circuits).

The automatic noise elimination circuit 10 has a noise elimination circuit 17 and a noise detection circuit 12. The luminance signal Y and the two color difference signals CR and CB from the switching circuit 8 are supplied to the noise removing circuit 17. Noise detection circuit 12
Only the luminance signal Y is input from the switching circuit 8. The noise detection circuit 12 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y and outputs the noise amount detection signal to the microcomputer circuit 16. The microcomputer circuit 16 generates a noise removal amount signal for designating the noise removal amount by the noise removal circuit 17 according to the noise amount signal and outputs it to the noise removal circuit 17.

The noise removing circuit 17 receives the input luminance signal Y and two color difference signals C according to the noise removal amount signal.
Noise removal is performed on R and CB. The luminance signal Y from which the noise is removed and the two color difference signals CR and CB are supplied to the sequential scan conversion circuit 13. The progressive scan conversion circuit 13 includes
Input interlaced luminance signal Y and color difference signal C
R and CB are progressive luminance signal Y and color difference signal C
Convert to R, CB. Luminance signal Y that has undergone sequential scanning line conversion
The two color difference signals CR and CB are converted into RGB signals by the luminance color difference → RGB conversion circuit 14. The RGB signal from the luminance color difference → RGB conversion circuit 14 is displayed by the display device 15.
Is supplied to and displayed as an image.

By the way, the multi-screen display circuit 7 is provided with a memory for storing a video signal, and the multi-screen display is carried out by independently controlling the writing and reading of the digitized video signal to and from the memory. It is possible. That is, the multi-screen display circuit 7 uses, for example, a write control signal that is synchronized with the second video signal and a read control signal that is generated from a reference synchronization signal that is not synchronized with this video signal to control the write of the second video signal. The signal is used to write to the memory, and the video signal stored in the memory is read using the read control signal. As a result, the video signal read from the memory is synchronized with the reference synchronization signal. If this reference synchronization signal is generated from the first video signal displayed simultaneously with the second video signal, independent first and second video signals can be mixed and displayed.

In this case, the multi-screen display circuit 7 is
In order to reduce the capacity required for the memory, in the horizontal and vertical blanking periods, the data corresponding to the level of the video signal is not written in the memory but is converted into predetermined digital data and stored. ing. Therefore, during multi-screen display, noise detection cannot be performed using the horizontal and vertical blanking periods of the luminance signal Y from the multi-screen display circuit 7. If the noise detection circuit 12 performs noise detection, a noise amount signal indicating that the noise amount is 0 is generated. In this case, the noise removing circuit 17
Noise removal cannot be performed at.

[0014]

As described above, in the conventional noise eliminator, when performing a single screen display,
It is possible to remove noise by detecting noise.However, when performing multi-screen display, the level information of the horizontal and vertical blanking periods is not stored to reduce the capacity of the video memory. However, there is a problem that the noise of the video signal cannot be removed.

The present invention has been made in view of the above problems, and it is possible to accurately detect the amount of noise by performing noise detection in the preceding stage of the multi-screen display processing. It is an object of the present invention to provide a noise eliminator capable of surely removing noise even if there is, and capable of obtaining a high quality image.

[0016]

A noise removing device according to the present invention is provided with a separating means for receiving one or more kinds of video signals and for separating a luminance signal and a chrominance signal from each input video signal, and the separating means. A multi-screen display processing means for performing multi-screen display processing for multi-screen displaying an image based on the one or more types of video signals, to which the luminance signal and the color signal separated by the means are given, and the multi-screen display processing. Switching means for switching and outputting between the output of the means and the output based on one video signal from the separating means, the first noise detecting means for detecting the noise amount of the luminance signal included in the output of the switching means, Second noise detecting means for detecting the noise amount of one or more luminance signals input to the multi-screen display processing means, and the output of the first noise detecting means at the time of one-screen display is selected to obtain the selected noise amount. The noise removal amount to be removed is calculated on the basis of the noise removal amount, and the output of the second noise detecting means is selected in the multi-screen display, and the noise removal amount to be removed is calculated based on the selected one or more noise amounts. The calculation means and the noise removal means for respectively removing the noise of the corresponding video signal in the output of the switching means based on the one or more noise removal amounts obtained by the calculation means.

In the present invention, one or more kinds of input video signals are separated into a luminance signal and a color signal by the separating means. The luminance signal and the color signal separated by the separating means are subjected to multi-screen display processing by the multi-screen display processing means. The switching means outputs the output based on the one video signal from the separating means during the one-screen display, and outputs the output from the multi-screen display processing means during the multi-screen display. The output of the switching means is given to the noise removing means. The first noise detecting means detects the noise amount of the output luminance signal of the switching means. On the other hand, the second noise detection means detects the noise amount of one or more luminance signals input to the multi-screen display processing means. When displaying one screen, the calculation means obtains the noise removal amount based on the output of the first noise detection means. on the other hand,
At the time of multi-screen display, the calculating means determines the noise removal amount based on one or more noise amounts from the second noise detecting means in association with each video signal. Based on the noise removal amount calculated by the calculation means, the noise removal means removes noise from the output of the switching means for the corresponding video signal. In this way, even during multi-screen display, the amount of noise is accurately obtained and noise is removed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a noise removing device according to the present invention. In FIG. 1, the same components as those in FIG. 5 are designated by the same reference numerals.

In the present embodiment, when the multi-screen display circuit and the motion adaptive progressive scan conversion circuit are composed of one IC, the noise removing function of this IC is utilized and
By detecting noise also in the circuit in the preceding stage of this IC, it is possible to surely remove noise from the video signal even in multi-screen display.

The video input terminals 1 and 4 have a first and a second, respectively.
The video signal of is input. These first and second video signals are supplied to the YC separation circuits 2 and 5, respectively. The YC separation circuit 2 separates the input first video signal into a luminance signal Y1 and a chroma signal, and the YC separation circuit 5 receives the input second video signal.
The video signal is separated into a luminance signal Y2 and a chroma signal.

The YC separation circuits 2 and 5 often have a noise detection function. In the present embodiment, YC
The noise detection circuit 23 included in the separation circuit 2 is used to detect noise. The noise detection circuit 23 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y1 included in the first video signal and outputs the noise amount detection signal.

The luminance signal Y1 and the chroma signal from the YC separation circuit 2 are supplied to the chroma demodulation circuit 3. The chroma demodulation circuit 3 performs color demodulation of the chroma signal to generate two color difference signals CR.
1 and CB1 are obtained. The chroma demodulation circuit 3 uses the color difference signal CR
1 and CB1 are output to the multi-screen display circuit 7 and the switching circuit 8. The luminance signal Y1 is output to the multi-screen display circuit 7 and the switching circuit 8 after being delayed by the delay time of the chroma demodulation process.

The luminance signal Y2 and the chroma signal from the YC separation circuit 5 are supplied to the chroma demodulation circuit 6. The chroma demodulation circuit 6 color demodulates the chroma signal to generate two color difference signals CR.
2 and CB2 are obtained. The chroma demodulation circuit 6 uses the color difference signal CR
2 and CB2 are output to the multi-screen display circuit 7 and the switching circuit 8. The luminance signal Y2 is output to the multi-screen display circuit 7 and the switching circuit 8 after being delayed by the delay time of the chroma demodulation process.

The multi-screen display circuit 7 converts the input video signal into a digital signal, compresses the data amount by subsampling in the horizontal direction, and records it in a memory (not shown). In this case, in order to reduce the capacity required for the memory, the multi-screen display circuit 7 does not write data according to the level of the video signal in the memory in the horizontal and vertical blanking periods, but rather sets the predetermined value. It is designed to be converted into digital data and stored.

The multi-screen display circuit 7 reads the stored video signal at a clock frequency synchronized with the horizontal and vertical sync signals obtained from the first video signal and converts it into an analog signal. In this case, the multi-screen display circuit 7 reads the luminance signal Y1 and the color difference signals CR1 and CB1 based on the first video signal at a timing corresponding to the left half area of the display screen, and the right half area of the display screen. Luminance signal Y2 and color difference signal CR based on the second video signal at a timing corresponding to
2 and CB2 are read. Thereby, the multi-screen display circuit 7
From, the multiple luminance signal YM, the multiple color difference signals CRM and CBM of the multiple image signals for displaying the image based on the first video signal on the left side of the screen and displaying the image based on the second video signal on the right side of the screen are can get.

The switching circuit 8 supplies these multiple luminance signals Y
M and multiple color difference signals CRM, CBM and chroma demodulation circuit 3
The luminance signal Y1 and the color difference signals CR1 and CB1 based on the first video signal are input. The switching circuit 8 receives the luminance signal Y1 and the color difference signal CR1, from the chroma demodulation circuit 3 when the one-screen display is instructed by the user operation.
CB1 is selected and output, and at the time of multi-screen display, the multi-luminance signal YM and multi-color difference signal CR from the multi-screen display circuit 7 are output.
Select M and CBM to output.

The output of the switching circuit 8 is supplied to the motion adaptive progressive scan conversion circuit 9 as a luminance signal Y and color difference signals CR and CB. The motion adaptive progressive scan conversion circuit 9 is composed of an automatic noise removal circuit 10 and a progressive scan conversion circuit 13. The automatic noise removal circuit 10 has a noise removal circuit 11 and a noise detection circuit 12.

The noise removal circuit 11 is supplied with the luminance signal Y and the two color difference signals CR and CB from the switching circuit 8. The noise removing circuit 11 includes a microcomputer circuit 24 described later.
From the noise removal amount signal, and the input luminance signal Y and two color difference signals C based on the noise removal amount signal.
Noise removal is performed on R and CB. Noise removal circuit 1
1 is a luminance signal Y and a color difference signal CR from which noise is removed,
The CB is output to the progressive scan conversion circuit 13. In the present embodiment, the noise removing circuit 11 is, as described later,
Noise removal processing can be performed for each image of the combined image.

The progressive scanning conversion circuit 13 converts the input luminance signal Y and color difference signals CR and CB into sequential scanning signals and outputs them to the luminance color difference → RGB conversion circuit 14. The luminance / color difference → RGB conversion circuit 14 converts the input luminance signal Y and the color difference signals CR and CB into RGB signals to display the display device 15.
Output to. The display device 15 is adapted to display an image based on the input RGB signals.

Only the luminance signal Y is input from the switching circuit 8 to the noise detection circuit 12 of the automatic noise removal circuit 10.
The noise detection circuit 12 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y and outputs the noise amount detection signal to the microcomputer circuit 24.

In the present embodiment, the microcomputer circuit 2
4 includes a noise detection signal selection circuit 25. The noise detection signal selection circuit 25 selects from the noise detection circuit 12 when the switching circuit 8 selects the output of the chroma demodulation circuit 3 and outputs it to the motion adaptive progressive scan conversion circuit 9, that is, in the case of single screen display. In the case where the switching circuit 8 selects the output of the multi-screen display circuit 7 and outputs it to the motion adaptive progressive scan conversion circuit 9, that is, in the case of multi-screen display, the noise detection circuit 23 is selected. The noise amount signal from is selected. The microcomputer circuit 24 generates a noise removal amount signal for designating the noise removal amount by the noise removal circuit 11 based on the noise amount detection signal selected by the noise detection signal selection circuit 25, and outputs it to the noise removal circuit 11. It is supposed to do.

In the present embodiment, the noise removing circuit 11 removes noise from the luminance signal and the color difference signal corresponding to the input noise removal amount signal. That is, in the single-screen display mode, the noise removal circuit 11 uses the input noise removal amount signal to output the luminance signal Y1 and the color difference signals CR1 and CB1 corresponding to the entire screen.
Remove the noise. On the other hand, in the multi-screen display mode,
The noise removing circuit 11 is based on the input noise removal amount signal, based on the multiple luminance signal YM and multiple color difference signals CRM,
Luminance signal Y1 and color difference signals CR1 and CB1 of CBM
The noise removal is performed only for the signal in the period based on.

Next, the operation of the embodiment configured as described above will be described.

The first and second video signals are input to the video input terminals 1 and 4, respectively. These video signals are YC
The separation circuits 2 and 5 separate the luminance signals Y1 and Y2 from each chroma signal. The YC separation circuit 2 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y1 by the built-in noise detection circuit 23 and outputs the noise amount detection signal to the microcomputer circuit 24.

The chroma demodulation circuits 3 and 6 perform color demodulation on the input chroma signals and output color difference signals CR1 and CB1 or color difference signals CR2 and CB2, respectively. Further, the chroma demodulation circuits 3 and 6 convert the input luminance signals Y1 and Y2 into
The output is delayed by the processing time of color demodulation.

Now, it is assumed that the single screen display mode for displaying only the main screen is selected. In this case, the switching circuit 8 selects the luminance signal Y1 and the color difference signals CR1 and CB1 from the chroma demodulation circuit 3 and outputs them to the motion adaptive progressive scan conversion circuit 9.

The noise signal detection circuit 12 of the motion adaptive progressive scan conversion circuit 9 receives the luminance signal Y1 and receives the luminance signal Y1.
The noise amount in the back porch period of the horizontal blanking period of is detected. The noise detection circuit 12 generates a noise amount detection signal based on the detected noise amount and outputs it to the noise detection signal selection circuit 25 of the microcomputer circuit 24.

In this case, the noise detection signal selection circuit 2
5 selects the output of the noise detection circuit 12. The microcomputer circuit 24 generates a noise removal amount signal for removing noise in the noise removal circuit 11 based on the noise amount detection signal from the noise detection circuit 12. This noise removal amount signal is supplied to the noise removal circuit 11, and the noise removal circuit 11 removes the noises of the luminance signal Y1 and the color difference signals CR1 and CB1 from the switching circuit 8 based on the noise removal amount signal and sequentially scans them. Output to the conversion circuit 13. Luminance signal Y1 and color difference signals CR1 and CB from which noise is removed
1 is converted into a sequential signal in the progressive scan conversion circuit 13 and output.

The output of the motion adaptive type progressive scan conversion circuit 9 is given to the luminance color difference → RGB conversion circuit 14 and converted into an RGB signal. This RGB signal is given to the display device 15, and the display device 15 displays an image based on the RGB signal.

Thus, in this case, the luminance signal Y1 and the color difference signal C based on the first video signal from the input terminal 1 are used.
The noise of R1 and CB1 is surely removed, and the image is displayed.

Next, it is assumed that the multi-screen display mode in which two screens based on the first video signal and the second video signal are displayed on the screen is selected. In this case, the switching circuit 8 selects the multiple luminance signal YM and the multiple color difference signals CRM and CBM from the multi-screen display circuit 7 and outputs them to the motion adaptive progressive scan conversion circuit 9. In the multiple luminance signal YM and the multiple color difference signals CRM and CBM, for example, the signal corresponding to the area on the left side of the screen is based on the luminance signal Y1 and the color difference signals CR1 and CB1.

The noise detection circuit 12 in the automatic noise removal circuit 10 automatically detects the noise amount in the back porch period of the horizontal blanking period and outputs a noise amount detection signal. However, in this case, the noise detection signal selection circuit 25 of the microcomputer circuit 24 selects the noise amount detection signal from the noise detection circuit 23. As described above, the noise detection circuit 2
Reference numeral 3 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y1 based on the first video signal separated by the YC separation circuit 2.

The microcomputer circuit 24 is the noise detection circuit 23.
A noise removal amount signal is generated based on the noise amount detection signal from. The noise removal amount signal is given to the noise removal circuit 11. The noise removing circuit 11 selects, for example, the luminance signal Y1 and the color difference signal CR1 on the left side of the screen from the input multiple luminance signal YM and the multiple color difference signals CRM and CBM.
, CB1 are subjected to noise removal processing based on the input noise removal amount signal. This allows
Noise is removed from the signals corresponding to the luminance signal Y1 and the color difference signals CR1 and CB1 among the multiple luminance signal YM and the multiple color difference signals CRM and CBM, and the signals are output.

Other functions are similar to those in the single-screen display mode. Thus, even in the multi-screen display mode, the first
And the luminance signal Y1 and the color difference signals CR1 and CB1 among the multiple luminance signal YM and the multiple color difference signals CRM and CBM based on the second video signal, that is, noise of the image based on the first video signal is surely removed, The image is displayed.

As described above, in the present embodiment, at the time of multi-screen display, the noise amount is detected from the luminance signal before the multiplexing process, and the noise removal amount signal created based on this noise amount is used to perform the multiplexing process. Noise removal processing is performed on the subsequent luminance signal and color difference signal, and reliable noise removal is possible.

That is, even when the multi-screen display circuit 7 and the motion adaptive type progressive scan conversion circuit 9 are made into blocks and integrated into an IC, the noise removal circuit in the IC is used and the multi-screen display circuit 7 is used. By providing the noise detection circuit 23 in the preceding stage, the noise amount can be detected even in the multi-screen display, and the noise removal circuit can eliminate the noise.
This is possible not only when displaying screens but also when displaying multiple screens.

Although the amount of noise is detected in the YC separation circuit 2 in the above embodiment, the amount of noise may be detected at any position as long as it is in the preceding stage of the multi-screen display circuit 7. For example, YC The noise amount may be detected by the noise detection circuit included in the separation circuit 5, or the noise amount may be detected for the luminance signal output from the chroma demodulation circuit 3.

FIG. 2 is a block diagram showing another embodiment of the present invention. 2, the same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In the embodiment of FIG. 1, the noise amount of the first video signal is detected by the noise detection circuit 2,
I was getting a noise amount signal. However, as described above, the noise can be removed also by detecting the noise amount of the second video signal. This embodiment is applied to this, and the noise removal performance is improved by using the noise amount detected from the corresponding video signal for the noise removal of each image displayed on the multi-screen. is there.

The present embodiment differs from the embodiment of FIG. 1 in that a noise detection circuit 31 is added. The noise detection circuit 23 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y1 and outputs the noise amount detection signal N1. The noise detection circuit 31 detects the noise amount in the back porch period of the horizontal blanking period of the luminance signal Y2 from the YC separation circuit 5, and outputs the noise amount detection signal N2 to the noise detection signal selection circuit 25 of the microcomputer circuit 24.
It is designed to be supplied to.

In the present embodiment, the noise detection signal selection circuit 25 selects the noise amount detection signal from the noise detection circuit 12 in the 1-screen display mode, and the noise detection circuits 23, 31 in the multi-screen display mode. The noise amount detection signals N1 and N2 from are selected.

When the noise detection signal selection circuit 25 selects the outputs of the noise detection circuits 23 and 31, the microcomputer circuit 24 generates noise removal amount signals R1 and R2 based on the noise amount detection signals N1 and N2, respectively. Then, the signal is output to the noise removing circuit 11.

In this embodiment, the noise removing circuit 11 removes noise from the luminance signal and the color difference signal corresponding to the input noise removal amount signal. That is, in the single-screen display mode, the noise removal circuit 11 uses the input noise removal amount signal to output the luminance signal Y1 and the color difference signals CR1 and CB1 corresponding to the entire screen.
Remove the noise.

On the other hand, in the multi-screen display mode, the noise removing circuit 11 receives the multiple luminance signal YM and the multiple color difference signals CRM and CB based on the input noise removal amount signal N1.
Of M, for example, the noise of the signal in the period based on the luminance signal Y1 and the color difference signals CR1 and CB1 corresponding to the left side of the screen is removed. Further, the noise removal circuit 11 is based on the input noise removal amount signal N2, based on the luminance signal Y2 and the color difference signals CR2 and CB2 corresponding to the right side of the screen among the multiple luminance signal YM and the multiple color difference signals CRM and CBM. Remove noise in the signal of the period.

Next, the operation of the embodiment thus configured will be described with reference to FIG. FIG. 3 is an explanatory diagram showing a noise removing method.

The operation in the single screen display mode is the same as that of the embodiment shown in FIG. In the multi-screen display mode, the noise detection circuits 23 and 31 detect the noise amount in the back porch period of the horizontal blanking period from the luminance signals Y1 and Y2 from the YC separation circuits 2 and 5, respectively, and detect the noise amount detection signal. N1
, N2 are output.

The noise detection signal selection circuit 25 selects the output of the noise detection circuit 23 and the noise detection circuit 31 in the multi-screen display mode. The microcomputer circuit 24 generates a noise removal amount signal R1 based on the noise amount detection signal N1 and a noise removal amount signal R2 based on the noise amount detection signal N2. The noise removal amount signals R1 and R2 from the microcomputer circuit 24 are supplied to the noise removal circuit 11. The noise removal circuit 11 removes the noise of the luminance signal Y1 and the color difference signals CR1 and CB1 corresponding to the left side of the screen in the input composite image based on the noise removal amount signal R1, and based on the noise removal amount signal R2. , The noise of the luminance signal Y2 and the color difference signals CR2, CB2 corresponding to the right side of the screen is removed from the input combined image.

FIG. 3 shows the display device 15 when displaying two screens.
The above screen display is shown. On the screen 50, the image 51 based on the first video signal is displayed on the left side and the second image 51 on the right side.
An image 52 based on the video signal is displayed. Image 5
In No. 1, noise is removed by noise removal processing based on the noise removal amount signal R1 for the luminance signal Y1 and the color difference signals CR1, CB1. The image 52 has its noise removed by noise removal processing based on the noise removal amount signal R2 for the luminance signal Y2 and the color difference signals CR2, CB2.

Other functions are similar to those of the embodiment shown in FIG.

As described above, also in this embodiment, as in the case of the embodiment of FIG. 1, the noise amount is surely detected and the noise removal amount signal is obtained in both the single-screen display and the multi-screen display. Can be generated and noise can be removed. Further, in the present embodiment, the noise amount is detected from the first and second video signals, the noise amount of each image of the composite image can be detected with high accuracy, and the optimum noise removal for each image can be performed. The effect can be obtained.

Also in this embodiment, it is apparent that each noise detection circuit may be arranged at any position in the preceding stage of the multi-screen display circuit 7.

Even when the multi-screen display has three or more screens, the noise amount in the back porch period of the horizontal period of the luminance signal for each video signal can be obtained before the multi-screen display processing. The noise can be removed for each image of the composite image.

FIG. 4 is a block diagram showing another embodiment of the present invention. 4, the same components as those in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

In the embodiment shown in FIG. 2, noise is detected by the two noise detection circuits 23 and 31. On the other hand, in the present embodiment, the noise amount of the first and second video signals is detected by one noise detection circuit 42.

In this embodiment, the noise detection circuit 23 is not used, the noise detection circuit 31 is deleted, the noise detection circuit 31 is provided, and the switching circuit 41 is added. Different from

The switching circuit 41 receives the luminance signals Y1 and Y2 from the YC separation circuits 2 and 5, respectively, and switches these luminance signals at a predetermined timing and outputs them to the noise detection circuit 42. For example, the switching circuit 41 is
The luminance signals Y1 and Y2 are switched and output for each field. The noise detection circuit 42 detects the noise amount in the back porch period of the horizontal blanking period of the input luminance signal Y1 and outputs it to the noise detection signal selection circuit 25 of the microcomputer circuit 24 as the noise amount detection signal N1. The noise amount in the back porch period of the horizontal blanking period of the luminance signal Y2 thus detected is detected and output to the noise detection signal selection circuit 25 of the microcomputer circuit 24 as the noise amount detection signal N2. The switching timing of the switching circuit 41 may be arbitrary.

In the present embodiment, the noise detection signal selection circuit 25 selects the noise amount detection signal from the noise detection circuit 12 in the one-screen display mode and outputs the noise detection circuit 42 in the multi-screen display mode. It is designed to be selected. The output of the noise detection circuit 42 includes a noise amount detection signal N1 indicating the noise amount of the luminance signal Y1 and a noise amount detection signal N2 indicating the noise amount of the luminance signal Y2.

When the noise detection signal selection circuit 25 selects the output of the noise detection circuit 42, the microcomputer circuit 24 detects the noise removal amount based on the two noise amount detection signals N1 and N2 from the noise detection circuit 42, respectively. Signals R1 and R
It is designed to ask for 2.

Also in the embodiment configured as described above, the operation in the single screen display mode is the same as that of the embodiment of FIG. In the multi-screen display mode, the switching circuit 41
The luminance signals Y1 and Y2 from the YC separation circuits 2 and 5 are switched at a predetermined timing and output to the noise detection circuit 42. The noise detection circuit 42 detects the noise amount of the luminance signals Y1 and Y2 in the back porch period of the horizontal blanking period, and outputs noise amount detection signals N1 and N2, respectively.

The noise detection signal selection circuit 25 selects the output of the noise detection circuit 42 in the multi-screen display mode. The microcomputer circuit 24 generates a noise removal amount signal R1 based on the noise amount detection signal N1 and a noise removal amount signal R2 based on the noise amount detection signal N2.

The noise removing circuit 11 removes the noise from the input multiple luminance signal YM and the color difference signals CR1 and CB1 for each video signal based on the noise removal amount signals R1 and R2. Thus, as in the case of FIG. 3, it is possible to obtain a composite image from which noise has been removed for each image.

Other functions are similar to those of the embodiment shown in FIG.

As described above, also in the present embodiment, as in the case of the embodiment of FIG. 2, the noise amount is surely detected and the noise removal amount signal is obtained in both the single-screen display and the multi-screen display. Can generate and remove noise, and also
The noise amount of the combined image can be detected with high accuracy for each image, and a high noise removal effect can be obtained. Also in this embodiment, it is clear that each noise detection circuit may be arranged at any position in the preceding stage of the multi-screen display circuit 7.

[0074]

As described above, according to the present invention, it is possible to accurately detect the amount of noise by performing noise detection in the preceding stage of the multi-screen display processing. As a result, even in multi-screen display. There is an effect that it is possible to reliably remove noise and obtain a high-quality image.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a noise removing device according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is an explanatory diagram for explaining the operation of the embodiment of FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional noise eliminator.

[Explanation of symbols]

2, 5 ... YC separation circuit, 3, 6 ... Chroma demodulation circuit, 7 ...
Multi-screen display circuit, 8 ... Switching circuit, 9 ... Motion adaptive progressive scan conversion circuit, 10 ... Automatic noise removal circuit, 11 ... Noise removal circuit, 12 ... Noise detection circuit, 13 ... Progressive scan conversion circuit, 14 ... Luminance color difference → RGB conversion circuit, 24 ... Microcomputer circuit, 25 ... Noise detection signal selection circuit.

Claims (5)

[Claims] 1. A separation means for inputting one or more kinds of video signals, for separating a luminance signal and a color signal from each input video signal, and a luminance signal and a color signal separated by the separation means. A multi-screen display processing means for performing multi-screen display processing for multi-screen displaying an image based on the one or more kinds of video signals; an output of the multi-screen display processing means;
A switching unit that switches and outputs an output based on a video signal, a first noise detecting unit that detects a noise amount of a luminance signal included in the output of the switching unit, and a 1 that is input to the multi-screen display processing unit. Second noise detecting means for detecting the noise amount of the above luminance signal, and a noise removal amount to be removed based on the selected noise amount by selecting the output of the first noise detecting means when displaying one screen However, in the multi-screen display, the output of the second noise detecting means is selected, and the calculating means calculates the noise removal amount to be removed based on the selected one or more noise amounts, and A noise removing device, comprising: a noise removing device that removes noise of a corresponding video signal in the output of the switching device based on one or more noise removing amounts. 2. The first and second noise detecting means,
The noise removing device according to claim 1, wherein the noise amount is detected in a back porch period of a horizontal blanking period of the luminance signal. 3. The noise removing apparatus according to claim 1, wherein the second noise detecting means is realized by a noise detecting function of the separating means. 4. The second noise detecting means detects noise amounts of a plurality of luminance signals input to the multi-screen display processing means, and the computing means is based on the noise amounts of the plurality of luminance signals. The noise removing apparatus according to claim 1, wherein the noise removing amount is calculated respectively. 5. The noise removing apparatus according to claim 4, wherein the second noise detecting unit detects the noise amount of each luminance signal while switching the plurality of luminance signals at a predetermined timing.