JP2002051234A - Apparatus and method for processing video signal and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise reducer having high vertical resolution and hardly detectable motion blurring. SOLUTION: The noise reducer is composed of a signal processing circuit 1 for removing a noise component from an inputted video signal, a frame memory 7 for temporarily holding the video signal from which the noise component is removed by the signal processing circuit 1, a memory controller 8 for controlling the write and read of the video signal to and from the frame memory 7, and a control circuit 13 for controlling the entire noise reducer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus and method, and a recording medium, for example, a video signal processing apparatus and method suitable for removing noise components from a video signal, and a recording medium. .

[0002]

2. Description of the Related Art Noise reducers for removing noise from video signals include a frame noise reducer using a frame memory and a field noise reducer using a field memory.

FIG. 1 shows the relative advantages and disadvantages of a noise reduction process of a frame noise reducer (hereinafter referred to as a frame NR process) and a noise reduction process of a field noise reducer (hereinafter referred to as a field NR process). Is shown.

[0004] The frame NR processing has a higher vertical resolution than the field NR processing. This means that when removing noise from a still image, the field N
This is an advantage of the frame NR process over the R process.

However, in the case of removing noise from a moving image, the frame NR processing has a disadvantage in that so-called “motion blur” can be easily detected because the vertical resolution is excellent. Note that it is possible to reduce the motion blur in the frame NR processing, but in such a case, the effect of noise removal is significantly reduced.

[0006]

As described above, the conventional noise reducer has a problem that it is impossible to achieve both high vertical resolution and no detection of motion blur.

The present invention has been made in view of such a situation, and has as its object to realize a noise reducer having a high vertical resolution and hardly detecting motion blur.

[0008]

According to the present invention, there is provided a video signal processing apparatus comprising: storage means for storing a video signal; read means for reading the video signal stored in the storage means as a first video signal; Calculating means for calculating a difference value between the second video signal and the first video signal read by the reading means; calculating means for calculating a noise component of the second video signal based on the difference value; Removing means for removing a noise component from the video signal, detecting means for detecting the amount of movement of the second video signal based on the difference value, and read control for controlling the reading means in accordance with the detection result of the detecting means Means.

[0009] The read-out control means, in accordance with the detection result of the detection means, a video signal which precedes the second video signal by one field or a video signal which precedes the second video signal by two fields, The reading means can be controlled so as to be read from the storage means as the first video signal.

According to the video signal processing method of the present invention, the video signal stored in the frame memory is read as a first video signal, and the read second video signal and the read video signal are read and processed in the reading step. Calculating a difference value from the first video signal, calculating a noise component of the second video signal based on the difference value, and removing the noise component from the second video signal And a detecting step of detecting a motion amount of the second video signal based on the difference value; and a reading control step of controlling a reading step in accordance with a detection result in the processing of the detecting step. Features.

[0011] The program of the recording medium of the present invention is read out by a readout step of reading out a video signal stored in a frame memory as a first video signal, and a readout step of reading the input second video signal. Calculating a difference value from the first video signal, calculating a noise component of the second video signal based on the difference value, and removing the noise component from the second video signal And a detecting step of detecting a motion amount of the second video signal based on the difference value; and a reading control step of controlling a reading step in accordance with a detection result in the processing of the detecting step. Features.

According to the video signal processing apparatus and method of the present invention, and the program of the recording medium, the stored video signal is read out as the first video signal, and read out with the input second video signal. A difference value from the first video signal is calculated, a noise component of the second video signal is calculated based on the difference value, and the noise component is removed from the second video signal. Further, the motion amount of the second video signal is detected based on the difference value. Further, reading of the first video signal is controlled according to the detection result.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given of a noise reducer according to an embodiment of the present invention. This noise reducer receives an input interlaced video signal (luminance signal).
(Y) and the color difference signal (CY)) perform a frame NR process or a field NR process in accordance with the user's selection when the image is a still image. The processing or the field NR processing is adaptively switched and executed.

FIG. 2 shows a configuration example of a noise reducer according to an embodiment of the present invention. The noise reducer includes a signal processing circuit 1 for removing a noise component from an input video signal, a frame memory 7 for temporarily holding the video signal from which the noise component has been removed by the signal processing circuit 1, and a writing of the video signal to the frame memory 7. And a memory controller 8 for controlling reading and a control circuit 13 for controlling the entire noise reducer.

The signal processing circuit 1 delays and adds the interlaced video signal from the input terminal by a predetermined time (the time required for processing by the adder 3, the motion detection circuit 4, and the feedback coefficient calculation circuit 5). A delay circuit 2 for outputting to a motion detecting circuit 4 and a feedback coefficient calculating circuit 5 by calculating a difference signal between a video signal input from the outside and a video signal supplied from a frame memory 7 , Adder 3
The motion amount of the video signal is detected and output to the feedback coefficient calculation circuit 5 on the basis of the difference signal from the CPU, and the motion amount is compared with the motion determination threshold value. A noise component is detected based on the motion detection circuit 4 to be output, the difference signal from the adder 3 and the amount of motion from the motion detection circuit 4, and is input from the feedback coefficient calculation circuit 5 to be output to the adder 6 and the delay circuit 2. The video signal is composed of a frame memory 7 and an adder 4 for subtracting the noise component input from the feedback coefficient calculation circuit 5 from the video signal and outputting the result to the output terminal.

The memory controller 8 determines whether the image signal input to the frame memory 7 is the first field or not.
An address generation counter 9 for generating a write address and a read address of a video signal for the frame memory 7 and supplying the write address and read address of the video signal to the frame memory 7 in response to the signal FS indicating whether the field is a field, (WE) and a WE / RE generating circuit 12 for outputting a read signal (RE) for instructing a read timing to the frame memory 7.

The address generation counter 9 further supplies a write address to the frame memory 7, and the frame NR
Frame NR address generation circuit 10 that supplies a read address for processing to switch 12, field NR address generation circuit 11 that supplies a read address for field NR processing to switch 12, and switch 1
The switch 12 is switched in response to a motion level signal from the motion detection circuit 4 and supplies a read address for frame NR processing or field NR processing to the frame memory 7.

The control circuit 14 controls the drive 15 to read a control program stored in the magnetic disk 16, the optical disk 17, the magneto-optical disk 18, or the semiconductor memory 19, and reads the read control program and a user program. Control the entire noise reducer based on the operation.

The operation of the noise reducer will be described.

First, a field NR for a still image
The processing will be described. It is assumed that the input video signal is a still image and that the field NR process is performed on the still image.

In the signal processing circuit 1, the adder 3 outputs a still image preceding the video signal of the still image (N-th field image) from the input terminal by one field read from the frame memory 7. (In this case,
The video signal of the (N-1st field image) is subtracted, and the obtained field difference signal is output to the feedback coefficient calculation circuit 5. The feedback coefficient calculation circuit 5 separates and shapes the field difference signal into noise and signal components, and outputs the obtained noise components to the adder 6.

On the other hand, the delay circuit 2 delays the video signal of the still image (N-th field image) from the input terminal while the adder 3 and the feedback coefficient operation circuit 5 execute the above-described processing. And outputs it to the adder 6. The adder 6 subtracts the noise component input from the feedback coefficient calculation circuit 5 from the video signal of the still image input from the delay circuit 2 and outputs the video signal from which noise has been removed to the output terminal and the frame memory 7. I do.

The video signal input to the frame memory 7 is written at the control timing of the memory controller 8 as shown in FIG. 3, and is used for a field image (N + 1th field image in this case) one field later. When a video signal is input, it is read and output to the adder 3.

FIG. 3A shows a V pulse (vertical retrace signal) of an input video signal. FIG.
(B) shows a write signal (WE) for instructing the write timing to the frame memory 7. FIG.
(E) shows a read signal (RE) for instructing the frame memory 7 to read timing.

Next, the frame NR processing for a still image will be described. Note that the input video signal is a still image, and that the still image has a frame NR
It is assumed that the processing is set in advance.

In the signal processing circuit 1, the adder 3 outputs a still image preceding by one frame read from the frame memory 7 from the video signal of the still image (N-th field image) from the input terminal. (In this case, N
The video signal of the (-2nd field image) is subtracted, and the obtained frame difference signal is output to the feedback coefficient calculation circuit 5. The feedback coefficient calculation circuit 5 separates and shapes the frame difference signal into noise and signal components, and outputs the obtained noise components to the adder 6.

On the other hand, the delay circuit 2 delays the video signal of the still image (N-th field image) from the input terminal while the adder 3 and the feedback coefficient calculation circuit 5 execute the above-described processing. And outputs it to the adder 6. The adder 6 subtracts the noise component input from the feedback coefficient calculation circuit 5 from the video signal of the still image input from the delay circuit 2 and outputs the video signal from which noise has been removed to the output terminal and the frame memory 7. I do.

The video signal input to the frame memory 7 is written at the control timing of the memory controller 8 as shown in FIG. 4, and is used for the field image (N + 2th field image in this case) one frame later. When a video signal is input, it is read and output to the adder 3.

FIG. 4A shows a V pulse (vertical retrace signal) of an input video signal. FIG.
(B) shows a write signal (WE) for instructing the write timing to the frame memory 7. FIG.
(E) shows a read signal (RE) for instructing the frame memory 7 to read timing.

Next, an adaptive NR process that adaptively switches and executes the field NR process and the frame NR process according to the motion amount of a moving image will be described with reference to the flowchart of FIG. It is assumed that the video signal input to the noise reducer is a moving image. The input first field image is not subjected to noise removal since the preceding image is not written in the frame memory 7 and the first field image is not subjected to noise removal.
Is written to.

In step S1, a field image preceding the field image input from the input terminal by one frame (two fields) is stored in the frame memory 7.
Is determined, and if it is determined that the field image preceding by one frame has not been written into the frame memory 7, the frame NR process using the field image preceding by one frame is still executed. Since it cannot be performed, the process proceeds to step S3.

In step S3, a field NR process is performed on the field image input from the input terminal. More specifically, the adder 3 determines that the Nth field image signal input from the input terminal is N fields ahead by one field read from the frame memory 7.
The first field image is subtracted, and the obtained field difference signal (difference value) is output to the motion detection circuit 4 and the feedback coefficient calculation circuit 5. The motion detection circuit 4 detects the motion amount of the video signal based on the difference signal from the adder 3 and outputs the motion amount to the feedback coefficient calculation circuit 5. Also, the motion detection circuit 4
Is compared with the detected motion amount and the threshold value for motion determination.If the motion amount is equal to or greater than the threshold value for motion determination, the motion level signal is set to High; conversely, if the motion amount is smaller than the threshold value for motion Low is output to the memory controller 8 as a level signal.

On the other hand, while the adder 3, the motion detecting circuit 4, and the feedback coefficient calculating circuit 5 execute the above-described processing, the delay circuit 2 outputs the video signal of the N-th field image from the input terminal. Is delayed and output to the adder 6. The adder 6 subtracts the noise component input from the feedback coefficient calculation circuit 5 from the video signal of the field image input from the delay circuit 2 and outputs the video signal from which noise has been removed to the output terminal and the frame memory 7. I do.

Thereafter, when the next field image is input from the input terminal, the process returns to step S1. If it is determined in step S1 that a field image preceding by one frame has been written in the frame memory 7, the process proceeds to step S2.

In step S2, the address generation counter 9 of the memory controller 8 determines whether the motion level signal from the motion detection circuit 4 is High or Low, and determines that the motion level signal is Low. , The memory controller 8 switches the switch 12 to the frame NR address generation circuit 10 side. As a result, FIG.
As shown in (1), a field image preceding the field image input to the input terminal by one frame (two fields) is read from the frame memory 7 and supplied to the adder 3. The process proceeds to step S4.

In step S4, a frame NR process is performed on the input field image. More specifically, the adder 3 determines that the video signal of the N-th field image input from the input terminal is N frames preceding by one frame (two fields) read from the frame memory 7.
The second field image is subtracted, and the obtained frame difference signal (difference value) is output to the motion detection circuit 4 and the feedback coefficient calculation circuit 5. The motion detection circuit 4 detects the motion amount of the video signal based on the difference signal from the adder 3 and outputs the motion amount to the feedback coefficient calculation circuit 5. Also, the motion detection circuit 4
The detected motion amount is compared with the motion determination threshold value. If the motion amount is equal to or greater than the motion determination threshold value,
Conversely, when the motion amount is less than the motion determination threshold, Low is set as the motion level signal to the memory controller 8.
Output to

On the other hand, while the adder 3, the motion detecting circuit 4, and the feedback coefficient calculating circuit 5 perform the above-described processing, the delay circuit 2 outputs the video signal of the N-th field image from the input terminal. Is delayed and output to the adder 6. The adder 6 subtracts the noise component input from the feedback coefficient calculation circuit 5 from the video signal of the field image input from the delay circuit 2 and outputs the video signal from which noise has been removed to the output terminal and the frame memory 7. I do.

Thereafter, when the next field image is input from the input terminal, the process returns to step S1, and the subsequent processes are repeated.

If it is determined in step S2 that the motion level signal is high, the switch 12 is switched to the field NR address generation circuit 11 side. As a result, as shown in FIG. 6, a field image preceding the field image input to the input terminal by one field is read out from the frame memory 7 and supplied to the adder 3. The process proceeds to step S3.

As described above, steps S1 to S1
The process 4 is executed every time a field image is input to the input terminal, and is repeated while the power of the noise reducer is cut off.

With such adaptive NR processing, the noise reducer can perform field NR processing in which it is difficult to detect motion blur when the amount of motion of the input moving image is large. When the amount of motion is small, it is possible to perform a frame NR process with a high vertical resolution.

FIG. 6 is a diagram showing the timing of write control and read control of the frame memory 7 by the memory controller 8 in the adaptive NR process.
According to the figure, it can be seen that the frame NR process is executed when the motion level signal is low, and the field NR process is executed when the motion level signal is low.

Incidentally, the above-described series of processing can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software can execute various functions by installing a computer built into dedicated hardware or installing various programs. It is installed from a recording medium into a possible general-purpose personal computer or the like.

As shown in FIG. 2, the recording medium is a magnetic disk 16 (including a floppy disk) on which the program is recorded and an optical disk 17 which are distributed separately from the computer to provide the program to the user.
(CD-ROM (Compact Disc-Read Only Memory), DVD (Digit
al Versatile Disc), magneto-optical disc 18 (M
D (including Mini Disc)) or a packaged medium including a semiconductor memory 19 and the like, which is provided to the user in a state in which it is incorporated in a computer in advance, and a ROM or a hard disk in which a program is recorded. It consists of.

In this specification, steps for describing a program to be recorded on a recording medium are not limited to processing performed in chronological order according to the described order, but are not necessarily performed in chronological order. Alternatively, it also includes individually executed processing.

In this specification, the system is
It represents the entire device composed of a plurality of devices.

[0047]

As described above, according to the video signal processing apparatus and method and the recording medium program of the present invention,
A difference value between the input second video signal and the read first video signal is calculated, and a motion amount of the second video signal is detected based on the difference value. Since the reading of the video signal is controlled, it is possible to realize a noise reducer having a high vertical resolution and hardly detecting motion blur.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating relative advantages and disadvantages of a frame NR process and a field NR process.

FIG. 2 is a block diagram illustrating a configuration example of a noise reducer according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a process of performing a field NR process on a still image.

FIG. 4 is a diagram illustrating a process of performing a frame NR process on a still image.

FIG. 5 is a flowchart illustrating adaptive NR processing for a moving image.

FIG. 6 is a diagram for explaining adaptive NR processing for a moving image.

[Explanation of symbols]

1 signal processing circuit, 2 delay circuit, 3 adder,
4 motion detection circuit, 5 feedback coefficient calculation circuit, 6 adder, 7 frame memory, 8 memory control, 9 address generation counter, 10 frame N
R address generator, 11 field NR address generator, 12 switches, 13 WE / RE
Generator circuit, 14 control circuit, 16 magnetic disk,
17 optical disk, 18 magneto-optical disk, 19
Semiconductor memory

Claims (5)

[Claims] 1. A video signal processing apparatus for removing a noise component from a video signal, wherein: storage means for storing the video signal; and read means for reading the video signal stored in the storage means as a first video signal. Calculating means for calculating a difference value between the input second video signal and the first video signal read by the reading means; and the noise component of the second video signal based on the difference value Calculating means for calculating the second video signal; removing means for removing the noise component from the second video signal; detecting means for detecting a motion amount of the second video signal based on the difference value; A video signal processing device comprising: a read control unit that controls the read unit in accordance with a detection result. 2. The video signal processing apparatus according to claim 1, wherein said storage means is a frame memory. 3. The read control means, wherein the video signal preceding the second video signal by one field or the video signal preceding the second video signal by two fields in response to a detection result of the detection means. The video signal
2. The video signal processing device according to claim 1, wherein the read unit is controlled to read the first video signal from the storage unit. 4. A video signal processing method for a video signal processing apparatus for removing a noise component from a video signal, comprising: a reading step of reading the video signal stored in a frame memory as a first video signal; Calculating a difference value between the second video signal and the first video signal read in the processing of the reading step; and calculating the noise component of the second video signal based on the difference value A calculating step, a removing step of removing the noise component from the second video signal, a detecting step of detecting a motion amount of the second video signal based on the difference value, and a processing of the detecting step. A read control step of controlling the processing of the read step in response to the detection result of the above. 5. A video signal program for removing a noise component from a video signal, comprising: a reading step of reading out the video signal stored in a frame memory as a first video signal; A calculating step of calculating a difference value between the video signal and the first video signal read in the processing of the reading step; and calculating the noise component of the second video signal based on the difference value A step of removing the noise component from the second video signal; a detection step of detecting a motion amount of the second video signal based on the difference value; and a detection in the processing of the detection step A read control step of controlling the processing of the read step in response to the result. The recording medium on which the system is recorded.