JP2002033941A - Apparatus and method for processing signal, picture signal recording device, and picture signal reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve optimum noise reduction effect which corresponds to a state of reception by a tuner when noise is reduced in picture signals. SOLUTION: The state of reception by the tuner 1 is judged in a state-of- reception judging circuit 31, and the result of judgment is transmitted to a noise reduction process control circuit 33. Picture signals, obtained from the tuner 1 through an input changer 2, is subjected to noise reduction process through a noise reducing circuit 32 and outputted. An amount-of-noise detecting circuit 34 detects the amount of noise present in picture signals. The noise reduction process control circuit 33 controls the noise reduction process in the noise reducing circuit 32, according to the state of reception from the state- of-reception judging circuit 31 and the amount of noise from the amount-of-noise detecting circuit 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing apparatus and method for performing noise reduction processing of a video signal, a video signal recording apparatus, and a video signal reproducing apparatus.

[0002]

2. Description of the Related Art When a television broadcast is received by a tuner such as a television receiver or a video tape recorder,
When the reception state of the radio wave is poor, noise is often mixed in the received video signal.

When the viewer wants to remove noise in such a receiving state, for example, the user can set a noise reduction processing function according to the amount of noise while watching the image to remove the noise and listen to the preview. Like that.

[0004]

When a broadcast is being received by a tuner, the reception state of the tuner changes mainly due to a change in the weather, switching of the receiving broadcast station, and the like, and the amount of noise mixed in with this. Is changed, the viewer needs to reset the noise reduction processing accordingly.

When the noise reduction is controlled by detecting the amount of noise, even if a video signal containing no noise is input, the video contains noise intended by the maker or a signal similar to noise. In such a case, there is a possibility that an error signal may be generated by determining the noise and performing noise reduction processing on the noise.

[0006] The present invention has been proposed in view of the above-mentioned circumstances, and the noise reduction processing is different depending on whether the possibility that noise is mixed into the input signal itself is high or not. It is an object of the present invention to provide a signal processing device and method, a video signal recording device, and a video signal reproducing device capable of realizing optimal viewing of a video signal or the like.

[0007]

In order to solve the above-mentioned problems, a signal processing apparatus and method according to the present invention detect a state of an input signal, detect a noise amount of the input signal, and And controlling the noise reduction processing according to the input signal state and the detected noise amount.

More specifically, the reception state of the tuner is detected and determined, the noise amount of the input video signal is detected, the noise of the input video signal is reduced, and the reception state and the detected noise amount are reduced. Controlling the noise reduction processing accordingly.

Further, a video signal recording apparatus according to the present invention comprises:
Detects and determines the receiving state of the tuner, detects the amount of noise of the input video signal, reduces the noise of the input video signal, and controls the noise reduction processing according to the receiving state and the detected amount of noise. The video signal subjected to the noise reduction processing is recorded on a recording medium.

[0010] Further, a video signal reproducing apparatus according to the present invention comprises:
When reproducing the recording medium on which the reception state determination information obtained by detecting and determining the reception state of the tuner is recorded together with the video signal, the noise amount of the reproduced video signal is detected, and the noise reduction processing of the reproduced video signal is performed. Is controlled according to the reception state determination information and the detected noise amount.

According to an input signal state, for example, a reception state in a tuner, and a noise amount mixed in an input signal (for example, a video signal), a noise reduction process is adaptively controlled to obtain a desired characteristic. In addition, the process of reducing noise intentionally mixed is suppressed, the process of reducing noise when reception conditions are poor is enhanced, and a video signal or the like can be viewed in an optimal state for the viewer.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. First, an example of a disk recording / reproducing apparatus to which the present invention can be applied will be described with reference to FIG.

In FIG. 1, a television broadcast signal received by an antenna or the like is sent to a tuner 1 such as a terrestrial tuner via an input terminal 101. The video output and the audio output of the tuner 1 are supplied to an input switch 2. Similarly, external composite video and audio signals are also
The signals are supplied to the input switch 2 via the input terminals 102 and 103, respectively. The input switch 2 selects a desired signal in accordance with an instruction from the system controller 16, and outputs a composite video signal to the Y / C separation circuit 3 and an audio signal to the audio A / D converter 10.

The system controller 16 controls all the blocks described later. In addition, the system controller 16 controls the ROM (Read O / O) via the host bus.
nlyMemory) 17, RAM (Randam Access Memory) 1
8 is accessed as needed to perform overall control.

The Y / C separation circuit 3 separates a Y (luminance) signal and a C (chroma) signal from the composite video signal, and supplies them to an input switch 4. The input switch 4 is
According to an instruction by a control signal from the system controller 16, one of the input signal from the external S video input terminal 104 or the output from the Y / C separation circuit 3 is selected, and the
It is supplied to the decoder circuit 5.

The video signal input to the NTSC decoder 5 is subjected to processing such as A / D conversion and chroma encoding.
It is converted into a digital component video signal (hereinafter referred to as image data) and supplied to a pre-processing (pre-video signal processing) circuit 7. Further, the NTSC decoder 5 supplies a clock generated based on the horizontal synchronization signal of the input video signal and a horizontal synchronization signal, a vertical synchronization signal, and a field determination signal obtained by synchronizing and separating to the synchronization control circuit 6.

The synchronization control circuit 6 generates a clock and a synchronization signal, which are converted into timings necessary for each block described later, based on these signals, and supplies them to each block.

In the pre-processing (pre-video signal processing) circuit 7,
The input image data is subjected to various video signal processing such as pre-filtering and noise reduction processing, and is supplied to a video encoder, for example, an MPEG (Moving Picture Experts Group) encoder 8 and a post-processing (post-video signal processing) circuit 20.

In the embodiment of the present invention, as will be described later, for example, the noise reduction processing in the pre-processing (pre-video signal processing) circuit 7 is performed according to the state of the input signal, for example, by the tuner 1 (particularly the terrestrial tuner). Is controlled in accordance with the reception state of (i). Specifically, for example, the noise reduction processing at the time of a weak electric field having a bad reception state is performed more strongly than at the time of a strong electric field having a good reception state or a normal electric field. Is controlled.

The MPEG encoder 8 performs an encoding process such as block DCT (Discrete Cosine Transform) on the image data from the pre-processing circuit 7, generates an elementary stream (ES) of the image, and multiplexes the image.・
It is supplied to a separation circuit (multiplexer / demultiplexer) 9. Although the present embodiment employs the MPEG compression method, other compression methods or non-compression methods may be used.

On the other hand, the audio signal selected by the input switch 2 is converted into a digital audio signal by the A / D converter 10 and then supplied to an audio encoder, for example, an MPEG audio encoder 11. After compression according to the MPEG format by the MPEG audio encoder, an ES is generated, and the multiplexing / demultiplexing circuit 9 is generated similarly to the video signal.
To supply. In this embodiment, the encoding of the audio is performed by the MPEG method. However, it is needless to say that another compression method may be adopted, or that the audio may be uncompressed.

In the multiplexing / demultiplexing circuit 9, when recording, the video ES
(Elementary stream), multiplexing processing of audio ES and various control signals, and separation processing of a transport stream (Transport Stream: TS) at the time of reproduction.
The multiplexing / demultiplexing circuit 9 multiplexes the input MPEG video ES (elementary stream), the MPEG audio ES, and various control signals, and performs multiplexing processing.
A TS (transport stream) of the G system is generated and supplied to the buffer control circuit 14.

The buffer control circuit 14 converts the continuously input TS into a hard disk drive (Hard Dis
c Drive: HDD) Control for intermittently sending to 15 is performed. For example, when the HDD (hard disk drive) 15 is performing a seek operation, the TS cannot be written. Therefore, the TS is temporarily stored in a buffer, and when writing is possible, the writing is performed at a rate higher than the input rate. By doing so, the continuously input TS signal is recorded without interruption.

The HDD 15 includes a system controller 16
And records the TS at a predetermined address.

In this embodiment, the protocol of the buffer control circuit 14 and the HDD 15 is IDE (Intell.
igent Drive Electronics), but is not limited to this. Further, in the present embodiment, the HDD has been described as an example of the recording medium.

Next, the reproducing operation will be described. HDD
Reference numeral 15 is controlled by the system controller 16 to seek a predetermined address, read a TS (transport stream) signal, and
To supply. The buffer control circuit 14 performs buffer control so that the intermittently input signal is continuous.
The TS is supplied to the multiplexing / demultiplexing circuit 9. Multiplexing / demultiplexing circuit 9
Means TS to PES (Packetized Elementary Stream)
And an AV (Audio Video) decoder, for example, MP
It is supplied to the EG AV decoder 19.

The MPEG AV decoder 19 separates the input PES into a video ES and an audio ES, supplies them to a video MPEG decoder and an audio decoder, respectively, and performs a decoding process. As a result of the processing, baseband image data and audio data are obtained and supplied to a post-processing (post-video signal processing) circuit 20 and a changeover switch 23, respectively.

In the post-processing circuit, image data from the MPEG AV decoder 19 and pre-processing (pre-video signal processing)
The image data is supplied to the OSD (On Screen Display) circuit 21 by switching, synthesizing, and filtering the image data from the circuit 7.

The OSD circuit 21 generates graphics for screen display and the like, performs processing such as superimposition on image data and partial display, and performs NTSC encoder 22 processing.
To supply.

The NTSC encoder 22 converts the input image data (component digital signal) into a YC (luminance, chroma) signal, and then performs D / A conversion to obtain an analog composite video signal and an S video signal. These composite video signals are output to the outside via an output terminal 106, and the S video signals are output to the outside via an output terminal 107.

On the other hand, in the changeover switch 23, the MPEG
The audio data supplied from the AV decoder 19 and the audio A
The audio data input from the / D converter 10 is selected, and the audio data is converted into an analog audio signal by the audio D / A converter 24. An analog audio signal from the audio D / A converter 24 is taken out via an output terminal 108.

Next, digital signals supplied and output via the digital IN / OUT terminal 105 will be described. For example, an external IRD (Integrated Receiver Deco
der), the digital signal is input to the digital interface circuit 12 when recording a signal input via a digital interface such as IEEE1394.

In the digital interface circuit 12,
Processing such as format conversion is performed so as to conform to this method, and a TS is generated and supplied to the multiplexing / demultiplexing circuit 9. Multiple
The separation circuit 9 further analyzes and generates control signals and the like.
TS conversion adapted to this method is supplied to the subsequent stage. The subsequent processing is the same as the processing of the image data and the audio data described above. At the same time, a demultiplexing process is performed by the multiplexing / demultiplexing circuit 9 and the MPEG AV decoder 19
By supplying ES, analog video and audio signals can be obtained.

Next, the operation of the digital interface circuit 12 during reproduction will be described. When playing back,
Since the processing up to the separation circuit 9 is the same as the processing described above,
Description is omitted.

The TS input to the multiplexing / demultiplexing circuit 9 analyzes and generates a control signal as necessary, and supplies the control signal to the digital interface circuit 12. The digital interface circuit 12 performs a conversion reverse to that at the time of recording, converts it into a digital signal conforming to an external IRD,
Output via the N / OUT terminal 105. At the same time, a demultiplexing process is performed by the multiplexing / demultiplexing circuit 9 and MPEG
By supplying the PES to the AV decoder 19, analog video and audio signals can be obtained. In this embodiment, the connection with the IRD has been described, but the connection with an AV device such as a TV or a personal computer is also possible.

Next, a configuration example of a noise reduction device used in the embodiment of the present invention will be described with reference to FIG. FIG. 2 shows the tuner 1, the input switch 2, and the preprocessing circuit 7 of FIG.
In the preprocessing circuit 7, adaptive noise reduction processing is performed according to the reception state of the tuner. Although FIG. 2 does not show the Y / C separation circuit 3, the input changeover switch 4, and the NTSC decoder 5 in FIG. 1 for simplicity of explanation, these may be provided. Of course.

In FIG. 2, an RF signal of a broadcast video signal received by an antenna is input to a tuner 1 such as a terrestrial tuner via an input terminal 101. At this time, the RF signal may be attenuated due to the reception state of radio waves, the wiring state from the antenna to the tuner 1, and the like. The tuner 1 detects the level of the RF signal input at the input terminal 101, automatically adjusts the gain of the input amplifier, and outputs a video / audio signal after a constant signal level.

At this time, the input amplifier includes a so-called AG.
A C (automatic gain control) circuit is used to rectify, for example, an input signal and convert the amplitude of the input waveform into a voltage (AGC voltage) by envelope detection or the like for AGC operation. A voltage controlled amplifier (VC
By using A), the amplifier gain can be controlled with the detected voltage (AGC voltage). At this time, the AGC voltage, which is the output of the detector, indicates the amplitude of the RF input signal, and it is possible to determine the reception state by using this AGC voltage.

In this embodiment, the detection voltage (AGC)
Voltage) is input to the reception state determination processing circuit 31 of the preprocessing circuit 7, and the reception state is determined by comparing the voltage with a preset voltage value (threshold). For example, when the detection voltage is equal to or lower than the threshold, It is determined that the RF signal input is smaller than the set amplitude and the reception state is poor.

In this embodiment, the reception state of the tuner 1 is determined based on the detection voltage (AGC voltage). However, the present invention is not limited to this. The reception state may be determined using a ratio (carrier-to-noise ratio: C / N), or the reception state may be detected and determined by other various methods. Further, in the present embodiment, the reception state is determined in two levels of good and bad by comparing with one threshold, but a plurality of levels of determination may be performed by comparing with two or more thresholds. .

The video signal input switch 2 switches between an output video signal of the tuner 1 and an external video signal input from the input terminal 102, and selects an input of the system.

Noise reduction processing circuit (noise reducer)
Numeral 32 denotes a component for separating a noise component from the input video signal mixed with noise, for example, by subtracting the noise component from the video signal to reduce the noise, and for outputting the video signal to the output terminal 3.
5 is output.

Generally, in noise reduction processing, noise components that cannot be completely separated when noise components are separated reduce the effect of the reduction processing. However, if signal components are erroneously separated, an error signal is generated in the video signal. . Therefore, the noise reduction processing control circuit 32 of the present embodiment performs optimal processing on the input video signal by controlling, for example, the threshold value of the noise component separation processing.

Here, the noise reduction processing control circuit 32 will be described. For example, in the case of a method of separating noise components using a difference signal between frames or between fields of an input video signal, of the separated noise components, ,
Since a noise signal is likely to have a small amplitude, there is a known method in which a component having a certain amplitude or more is erroneously separated from a video signal and noise reduction processing is not performed. The threshold for comparing the amplitudes of the components is adaptively controlled by the noise reduction processing control 32.

In the example of FIG. 2, the noise amount detection processing circuit 34
By detecting the amount of noise mixed in the video signal, the threshold of the noise reduction processing control circuit 33 is increased when a large amount of noise component is mixed, and the noise reduction processing is also performed on the noise component having a large amplitude. In the case where only a small amount of noise is mixed in the video signal, the threshold value of the noise reduction processing control circuit 33 is reduced, and the noise reduction processing is performed only on the noise component having a small amplitude.

In the embodiment of the present invention, in addition to the information of the noise amount detection processing circuit 34, the information of the reception state of the tuner 1 receiving the input video signal is used. For example, when the RF signal input 25 is attenuated, the reception state is poor, and the input video signal contains more noise. Conversely, when the reception state is good, the noise becomes smaller.

The amount of noise detected by an input video signal is determined by the amount of noise added to the video signal by the creator of the video signal or when a video signal similar to noise is input.
It is difficult to separate from actual noise.

In the noise reduction processing control according to the embodiment of the present invention, when the reception state is poor, the noise reduction processing is performed by the noise reduction processing circuit 32 based on the noise amount detected by the noise amount detection processing. In a good case, the noise amount detected by the noise amount detection processing is subjected to noise reduction processing on the assumption that the video signal is erroneously detected. When the reception state is good, the control is performed by changing the control amount of the noise reduction processing (change to a direction in which the noise reduction processing is suppressed) or stopping the noise reduction processing. Alternatively, normal noise reduction processing may be performed when the reception state is good, and stronger noise reduction processing may be performed when the reception state is bad.

In an embodiment in which the control amount of the noise reduction process is changed, a plurality of control amounts of the noise reduction process with respect to the noise amount detection result are prepared and selected by judging the reception state. For example, if the reception state is poor, the control amount of noise reduction is increased according to the noise amount, and if the reception state is good, the noise reduction control amount is not increased for a certain amount of noise or more. It is possible.

Although the terrestrial tuner has been described here, a satellite broadcast receiving tuner can perform the same processing by judging the receiving state in the same manner. Further, even a system equipped with a plurality of tuners can be realized by determining the reception state of the tuner that outputs the video signal selected by the video signal input switch 2.

Although the reception state determination processing is not performed when an external video signal is input, the same processing can be performed by separately inputting information equivalent to reception state information from outside.

That is, in addition to the tuner receiving state,
If it is possible to detect or determine a state (input signal state) as to whether or not there is a high possibility that noise is mixed in the input signal itself, the noise reduction processing may be controlled according to the input signal state. Good. Specifically, for example, when the long time mode and the standard time mode are defined in the VTR standard or the like, it is known that noise is more likely to be mixed in the long time mode than in the standard time mode. Therefore, when the input signal is a reproduction signal from a VTR or the like, the input signal state is detected or determined as to whether the signal is a long mode reproduction signal or a standard time mode reproduction signal. Control may be performed to apply the reduction processing more strongly. In addition, when a plurality of compression coding schemes and compression ratios can be selected when a video signal is compressed and recorded, the higher the compression ratio, the higher the possibility that the amount of noise mixed in increases. The noise reduction processing may be controlled using the method and the compression ratio as the signal state determination information.

Next, an example of a configuration for noise reduction processing which is a main part of the preprocessing circuit 7 of FIG. 2 will be described with reference to FIG. The example of FIG. 3 shows a configuration example for noise reduction processing of a method of separating a noise component using a difference signal between frames or between fields.

A cyclic noise reduction processor using a frame memory as shown in FIG. 3 is known in the field of digital video signal processing. This reduces noise by extracting a low-level portion of the difference between the input video signal and the video signal one frame before from the frame memory as noise, and subtracting the extracted noise component from the input video signal. In addition, a signal with reduced noise is written into a frame memory. If a field memory is used instead of the frame memory, the capacity of the memory can be reduced.

In FIG. 3, an input video signal Vin converted into a digital signal is supplied from an input terminal 201, and this input video signal Vin is supplied to a first subtractor 202 and a second subtractor 204. The output video signal Vout of the first subtractor 202 is taken out to the output terminal 207,
The data is written to the frame memory 205. A memory controller 206 is provided in association with the frame memory 205. The memory controller 206 controls the write operation and the read operation of the frame memory 205.
The write data is delayed by one frame. If one frame delay is represented by F ⁻¹ , the frame memory 2
The output signal Vout · F ^-1 05 is supplied to the second subtractor 204. In the second subtractor 204, the input video signal Vin
Is supplied, a frame difference occurs.

The output video signal of the second subtractor 204 is supplied to the first subtractor 202 via the non-linear circuit 203. The non-linear circuit 203 multiplies the feedback coefficient K according to the level of the input signal, and is constituted by a ROM (read only memory). The input / output characteristics of the nonlinear circuit 203 are as follows. In a range where the input (frame difference) is small, the input is output as a noise component with K = 1, and in a range where the input is an intermediate level, the output is limited to a predetermined value. In a large range, the output is reduced, and when the input is large, the frame difference is calculated as
The output is set to 0.

As described above, the non-linear circuit 203 extracts the noise component using the characteristic that the correlation between frames is small and the amplitude is small. In the first subtractor 202, noise can be reduced by subtracting the extracted noise component from the input video signal.

Output video signal Vout from the noise reduction device
Can be expressed as: Vout = Vin−K · (Vin−Vout · F ⁻¹ ) = Vin · (1−K) / (1−K · F ⁻¹ ) As described above, in the noise reduction device shown in FIG. 3, a small amplitude component is extracted as noise from the difference between the input video signal and the video signal one frame before read from the frame memory, and the component is subtracted from the input video signal. To reduce noise. Also, the video signal with the noise reduced is written to the frame memory and used for processing the next frame. If an autocorrelation between fields is used instead of a frame, a similar configuration can be made using a field memory instead of a frame memory.

Further, as a configuration for use in the embodiment of the present invention shown in FIG. 2, for example, by controlling the separation process of a noise component in accordance with the determination result of the reception state, the input video signal can be controlled. It performs optimal processing. This is realized by changing the characteristics of the nonlinear circuit 203 according to the control signal supplied to the control signal input terminal 208 in FIG.

That is, the control signal input terminal 208
The reception state determination output from the reception state determination processing circuit 31 in FIG. 2 is input as a control signal. For example, when the reception state is poor, the nonlinear circuit 203 is controlled to have a characteristic of performing normal noise reduction processing, and When the condition is good,
The nonlinear circuit 203 is designed to suppress the amount of noise reduction.
Alternatively, the characteristic is controlled so as to stop the noise reduction processing. In this case, the reception state may be determined in multiple stages, and the characteristic of the nonlinear circuit 203 may be controlled in multiple stages.

The correspondence between the configuration in FIG. 2 and the configuration in FIG. 3 is, for example, that the noise reduction processing circuit 32 in FIG. 2 is used in the subtractor 202 in FIG. 3 and the noise reduction processing control circuit 33 in FIG. The noise amount detection processing circuit 34 of FIG. 2 substantially corresponds to the frame memory 205 and the subtractor 204 of FIG. 3, respectively.

Next, the operation of the reception state determination processing circuit 31 will be described with reference to the flowchart of FIG.

First, in step S 1, it is determined whether an input video signal is an input of the tuner 1 (particularly, a terrestrial tuner). This is determined by the switching state of the input switch 2 for the video signal or the like. If the input is not a tuner input, the reception state determination is not performed, and therefore, in step S5, noise reduction processing control for a state where noise is not congested is performed.

In the case of a tuner input, the determination of the reception state of the tuner is obtained from the reception state determination processing circuit 31 in step S2, the reception state is determined in step S3, and the reception by the antenna is a weak electric field (reception electric field strength). If it is determined that the RF input signal from the input terminal 1 is attenuated (e.g., low), it is determined that the reception state is poor and noise is mixed, and the process proceeds to step S4, where the output of the noise amount detection processing circuit 34 is weaker. Noise reduction processing control during electric field (NR control)
I do. If it is determined in step S3 that the reception state is good, the NR control (noise reduction processing control) in the normal electric field (or in the strong electric field) in step S5 is performed.

Here, in the NR control in the weak electric field and the NR control in the normal electric field, the NR control in the weak electric field performs the noise reduction processing more strongly. In particular,
By increasing (higher) the threshold value for separating the noise component according to the noise amount detected by the noise amount detection processing circuit 34 when the electric field is weak, the amplitude of the error signal between frames or between fields can be increased to some extent. Separating even large noise as noise and subtracting it from the input signal to perform larger noise reduction processing.

The processing of the present invention can also be used for a video signal recording device. That is, when used in a video signal recording / reproducing apparatus as shown in FIG. 1, when performing image compression such as MPEG, recording a video signal mixed with noise is performed based on a predetermined information amount. The amount of information for recording the noise signal itself is allocated, and the amount of information that can be used for recording a video signal is relatively reduced, which causes deterioration in image quality. This is particularly noticeable when the determined information amount is small, that is, when the compression ratio is high and the recording bit rate is low.

For this reason, by performing noise reduction processing control in advance according to the recording mode (set bit rate) used in the video signal recording apparatus, it is possible to perform recording with noise reduced in advance.

That is, in step S3 of FIG.
If the reception is a weak electric field and the video signal recording mode is set to a low bit rate, step S4
And if the bit rate is set to a high state, the process can proceed to step S5.

This is necessary for sufficiently recording a video signal even when the amount of information necessary for recording noise in which noise is mixed in the video signal input is subtracted when the bit rate is high. This is because the amount of information can be assigned, and the image quality is not significantly deteriorated.

When the present invention is applied to a video signal reproducing apparatus, the result of the reception state determination processing is recorded in advance on a recording medium or the like together with the video signal when recording the video signal.
By reading the reception state determination result simultaneously with the video signal when reproducing the video signal, it is possible to perform the same noise reduction processing.

That is, in the video signal recording / reproducing apparatus as shown in FIG. 1, when the video signal received by the tuner 1 is subjected to image compression such as MPEG and recorded, the video signal to be recorded is received. At the time of encoding by the video encoder 8 such as MPEG or the like, the reception result of the tuner 1 is recorded in, for example, a user data area prepared as MPEG encoded data. At this time, the switching state of the input switch 2 and the input switch 4 may be simultaneously recorded.

At the time of reproduction, when the compressed video signal is decoded by the AV decoder 19, the recorded tuner reception state and the like are read out, and the post-processing (post video signal processing) circuit 20 performs a noise reduction process. To control. In this case, the noise reduction processing and the control processing in the post-processing circuit 20 are the same as the noise reduction processing and the control processing in the pre-processing circuit 7 described above, and instead of the reception state determination processing circuit 31 in FIG. What is necessary is just to use the circuit which extracts the data of a receiving state from a signal.

The noise reduction processing is performed in the pre-processing circuit 9 and the post-processing circuit 20 in FIG. 1 to control the noise reduction processing. However, a filter processing is performed instead of the noise reduction processing. You may do so.
This filtering process is, for example, a low-pass filtering process, and has a function of making noise less noticeable. This filter processing (for example, low-pass filter processing)
May be controlled according to the input signal state as described above, for example, the reception state at the terrestrial tuner, or according to the noise amount or the like.

The present invention is not limited to the above-described embodiment. In the above-described embodiment, a hard disk is taken as an example of a signal recording medium. However, an optical disk, a flexible disk, a magnetic tape, or the like may be used. It is also possible to record the signal encoded by the apparatus of the present invention on a signal recording medium such as a magnetic recording medium or a semiconductor recording medium such as an IC card or various memories. Examples of the optical disk include a disk recorded by pits, a magneto-optical disk, a phase change optical disk, an organic dye optical disk, an optical disk recorded by ultraviolet laser light, and an optical disk having a multilayer recording film. Various discs can be used. In addition, it goes without saying that various changes can be made without departing from the spirit of the present invention.

[0075]

According to the present invention, the noise reduction processing is controlled in accordance with the state of the input signal, for example, the reception state in the terrestrial tuner. Can be performed. More specifically, the noise reduction processing is adaptively controlled in accordance with the reception state of the terrestrial tuner and the amount of noise mixed in the input video signal to obtain desired characteristics, thereby obtaining the desired characteristics. Therefore, noise reduction processing intentionally mixed is suppressed, noise reduction processing when reception conditions are poor is strengthened, and video signals and the like can be viewed in an optimal state for the viewer.

According to the present invention, when a video signal is recorded, the result of the reception state determination processing is recorded in advance on a recording medium or the like together with the video signal, and when the video signal is reproduced, the result of the reception state determination is simultaneously performed with the video signal , It is possible to perform a noise reduction process equivalent to the noise reduction process according to the reception state at the time of reproduction.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a video signal recording / reproducing apparatus.

FIG. 2 is a block diagram illustrating a configuration example near a noise reduction processing unit used in the embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration example of a noise reduction processing device used in the embodiment of the present invention.

FIG. 4 is a flowchart illustrating an example of a reception state determination process.

[Explanation of symbols]

1 tuner, 2 input selector, 4 input selector switch, 7 preprocessing (pre-video signal processing) circuit, 8
Video encoder, 9 multiplexing / demultiplexing circuit, 15 hard disk drive, 16 system controller,
19 AV decoder, 20 Post-processing (post video signal processing) circuit, 31 Reception state determination processing circuit, 32
Noise reduction processing circuit, 33 noise reduction processing control circuit, 34 noise amount detection processing circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kyoko Fukuda 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Hiroshi Kobayashi 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Shinya Igi 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Keiichi Shindo 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Sony F term in reference (reference)

Claims (18)

[Claims] 1. An input signal state detection means for detecting a state of an input signal; a noise amount detection means for detecting a noise amount of the input signal; a noise reduction processing means for reducing a noise of the input signal; Control means for controlling the noise reduction processing of the noise reduction processing means in accordance with the input signal state detected by the input signal state detection means and the amount of noise detected by the noise amount detection means. Processing equipment. 2. An input switching means for switching and selecting a plurality of input signals, wherein the control means includes: a switching state of the input switching means; an input signal state detected by the input signal state detecting means; 2. The signal processing device according to claim 1, wherein the noise reduction processing of the noise reduction processing means is controlled according to the amount of noise detected by the detection means. 3. The apparatus according to claim 1, wherein said input signal is a video signal received by a tuner, and said input signal state detection means is reception state determination processing means for determining a reception state of said tuner. Signal processing device. 4. The signal processing apparatus according to claim 3, wherein said reception state determination processing means determines said reception state using an automatic gain control voltage (AGC voltage) of said tuner. 5. The signal processing apparatus according to claim 3, wherein said reception state determination processing means determines said reception state using a carrier noise ratio (C / N) of said tuner. 6. The apparatus according to claim 1, wherein said control means controls the switching of the noise reduction processing of said noise reduction processing means in at least two stages according to the input state detected by said input state detection means. Signal processing device. 7. The control means stops the noise reduction processing of the noise reduction processing means when the noise amount detected by the noise amount detection means is equal to or greater than a predetermined threshold value, and sets the predetermined threshold value to the input state. 2. The signal processing apparatus according to claim 1, wherein the signal is variably controlled in accordance with an input state detected by the detection unit. 8. The apparatus according to claim 1, wherein said input signal is a video signal reproduced by a signal reproducing apparatus, and said input signal state detecting means is reproduction state determining processing means for judging a reproduction state of said signal reproducing apparatus. The signal processing device according to claim 1. 9. An input signal state detecting step of detecting a state of an input signal; a noise amount detecting step of detecting a noise amount of the input signal; a noise reducing processing step of reducing a noise of the input signal; A control step of controlling the noise reduction processing in the noise reduction processing step according to the input signal state detected in the input signal state detection step and the amount of noise detected in the noise amount detection step. Processing method. 10. An input switching step for switching and selecting a plurality of input signals, wherein the control step comprises: a switching state in the input switching step;
10. The noise reduction processing of the noise reduction processing step according to the input signal state detected in the input signal state detection step and the noise amount detected in the noise amount detection step. Signal processing method. 11. The apparatus according to claim 9, wherein said input signal is a video signal received by a tuner, and said input signal state detecting step is a receiving state determining processing step of determining a receiving state of said tuner. Signal processing method. 12. The signal processing method according to claim 11, wherein said reception state determination processing step determines said reception state using an automatic gain control voltage (AGC voltage) of said tuner. 13. A receiving state determination processing means for detecting and determining a reception state of a tuner; a noise amount detecting means for detecting a noise amount of an input video signal; and a noise reduction processing means for reducing a noise of the input video signal. Control means for controlling the noise reduction processing of the noise reduction processing means in accordance with the reception state detected by the reception state detection means and the amount of noise detected by the noise amount detection means; Recording means for recording a noise-reduced video signal on a recording medium. 14. The video signal recording apparatus according to claim 13, wherein said recording means records the determination of the tuner reception status obtained by said reception status determination processing means in said recording signal together with a video signal. . 15. The recording means has a plurality of recording modes, and the control means controls the reception state detected by the reception state detection means, the noise amount detected by the noise amount detection means, and the recording mode. 14. The video signal recording apparatus according to claim 13, wherein the noise reduction processing of said noise reduction processing means is controlled according to a recording mode of said means. 16. A reception state determination processing means for detecting and determining a reception state of a tuner; a noise amount detection means for detecting a noise amount of an input video signal; a filter processing means for filtering the input video signal; Control means for controlling characteristics of the filter processing means according to the reception state detected by the reception state detection means and the amount of noise detected by the noise amount detection means; and a video signal filtered by the filter processing means. A video signal recording device, comprising: recording means for recording on a recording medium. 17. The control means controls a filter coefficient of the filter processing means according to a reception state detected by the reception state detection means and a noise amount detected by the noise amount detection means. Claim 1
7. The video signal recording device according to item 6. 18. A video signal reproducing apparatus for reproducing a recording medium on which reception state determination information obtained by detecting and determining a reception state of a tuner is recorded together with a video signal, wherein the signal recorded on the recording medium is reproduced. Reproducing means for reproducing; noise amount detecting means for detecting a noise amount of a reproduced video signal obtained by the reproducing means; noise reducing processing means for reducing noise of the reproduced video signal; Control means for controlling the noise reduction processing of the noise reduction processing means according to the reception state determination information of the received signal and the amount of noise detected by the noise amount detection means. apparatus.