JPH0522749A - Reproducing device - Google Patents

Abstract

(57) [Abstract] [Purpose] By using a noise reduction memory when not using a memory for scanning or still image playback, it is possible to reduce the noise of chroma signals with a simple structure and low cost. At the same time, it can be integrated with a Y / C separation circuit, for example. A Y / C separation circuit 4 and a chroma decoder 24 for separating a video signal into a luminance signal and a color difference signal in a reproducing apparatus for storing a reproduced video signal in a field memory 2 and outputting a signal read therefrom as a still image. And a subtraction circuit 2 for subtracting the color difference signal from the memory 2 from this color difference signal
9, a low-pass filter 21 that extracts a noise component from the result, a limiter 22, and a subtraction circuit 17 that subtracts the noise component from the color difference signal from the decoder 24. When the noise of the color difference signal is reduced, the subtraction circuit 17 The color difference signal is stored in the memory 2, the color difference signal from the memory 2 is subtracted from the color difference signal from the decoder 24, and the noise component extracted therefrom is subtracted from the color difference signal from the decoder 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus suitable for application to, for example, a video disc player or the like.

[0002]

2. Description of the Related Art Conventionally, in a video disc player, in addition to a normal reproduction in which a video signal recorded on a disc is reproduced by an optical pickup, a reproduced image is reproduced as a still image or a desired image of the disc is reproduced. There is a so-called still image reproduction at the time of scanning for reproducing an image from a position.

A memory for storing a video signal, which is generally called a field memory, is used for reproducing such a still image.

That is, during normal reproduction by the video disk player, a reproduced video signal reproduced by the optical pickup from the disk is output, and during still picture reproduction or scanning, the video signal stored in the field memory is read out and reproduced. It is designed to do.

FIG. 7 shows an essential part of the video disc player as described above. In FIG. 7, reference numeral 1 is an input terminal to which a composite color video signal which is reproduced from an optical disk by an optical pickup and which has undergone a signal processing process such as a reproduction amplification circuit and a demodulation circuit is supplied. Are supplied to one fixed contact 3a of the switch 3 and the field memory 2, respectively.

The movable contact 3c of the switch 3 is provided with one fixed contact 3a or the other fixed contact 3 according to a control signal from a video disc player main body (not shown).
Connect to b.

That is, during normal reproduction, the control signal causes the movable contact 3c of the switch 3 to be one fixed contact 3a.
Connected to, for example, when scanning or playing still images,
By this control signal, the movable contact 3c of the switch 3 is connected to the other fixed contact 3b.

Therefore, during normal reproduction, the video signal reproduced from the disk is supplied to the Y / C separation circuit 4 via the switch 3, and during scanning or reproduction of still images.
The video signal read from the above memory is supplied to the Y / C separation circuit.

The Y / C separation circuit 4 separates the reproduced video signal supplied through the switch 3 or the video signal read from the memory 2 into a luminance signal Y and a chroma signal C.

The luminance signal Y from the Y / C separation circuit 4 is supplied to an output terminal 8 after being delayed by a delay circuit 5 for a predetermined time, and the component signal of another device is input through the output terminal 8. Supplied to the terminal.

On the other hand, the chroma signal C from the Y / C separation circuit 4 is supplied to the output terminal 7 and is supplied to the component input terminal of another device through the output terminal 7.

The luminance signal Y and the chroma signal C are also included.
Is added to the composite color video signal by the adder circuit 6 and then supplied to the output terminal 9, and is supplied to the composite input terminal of another device through the output terminal 9.

[0013]

In a so-called direct recording system such as a video disc player, since the S / N ratio of the luminance signal is relatively good, a chroma field noise reducer (noise) is applied to the chroma signal. Noise reduction by a reduction circuit) is effective in improving the image quality of the video signal.

Therefore, it is considered to use a field noise reducer in the above-mentioned video disc player.

However, in order to reduce the noise of the chroma signal by using this field noise reducer, memory for each field is required for each of the color difference signals RY and BY, so that the cost is greatly increased. Becomes

In order to solve the large increase in the storage capacity of the memory, there is a method of reducing the storage capacity of the memory by using a circuit for performing so-called thinning and interpolation, but in this case, these additional circuits are used. The circuit configuration is complicated and large. Further, in parallel with this, there is a disadvantage that good noise reduction cannot be performed due to the reduction of the storage capacity of the memory.

Further, due to such a problem that the circuit scale becomes large, there is a disadvantage that the noise reduction portion cannot be integrated with the Y / C separation circuit, for example.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a reproducing apparatus which has a simple structure, is inexpensive, and is capable of excellent noise reduction, and in which the noise reduction portion can be integrated into an integrated circuit. ..

[0019]

A reproducing apparatus of the present invention reproduces a video signal from a recording medium and stores the video signal reproduced from the recording medium in a memory 2 as shown in FIGS. In a reproducing device adapted to output the video signal read from the memory 2 as a still image,
Separating means 4 for separating the video signal into a luminance signal and a color signal,
24 and a first subtracting means 29 for subtracting the signals read from the memory 2 from the color signals from the separating means 4 and 24.
And noise extraction means 21 and 22 for extracting the noise component of the color signal from the subtraction result signal from the first subtraction means 29.
And a second subtracting means 17 for subtracting a noise component from the color signals from the separating means 4 and 24. When reducing the noise of the color signal, the color signal from the second subtracting means 17 is The noise component extracted from the subtraction result signal stored in the memory 2 and obtained by subtracting the color signal read from the memory 2 from the color signal from the separating means 4 and 24 is extracted from the color signal from the separating means 4 and 24. It is designed to be subtracted.

[0020]

According to the present invention described above, in the case of reducing the noise of the color signal, the color signal from the second subtracting means 17 is stored in the memory 2, and the color signals from the separating means 4 and 24 are stored in the memory 2. Since the noise component extracted from the subtraction result signal obtained by subtracting the color signal read from the memory 2 is subtracted from the color signal from the separating means 4 and 24, a new memory is not added. As a result, it is possible to provide a reproducing apparatus that can reduce the noise of color signals with a simple structure and low cost.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the reproducing apparatus of the present invention will be described in detail below with reference to FIG.

FIG. 1 shows the reproducing apparatus of this example, and the block diagrams shown in FIGS. 4 to 6 will be sequentially described below prior to the description thereof. FIG. 4 shows a part of a reproducing apparatus using a general chroma field noise reducer.

In FIG. 4, numeral 10 is reproduced from, for example, a disc by an optical pickup, and is read from a color video signal of, for example, an NTSC system or a memory (not shown) which has undergone a signal processing process such as a reproduction amplifier circuit and a demodulation circuit. The color video signal is supplied to the Y / C separation circuit, and the chroma signal C separated from the luminance signal Y by the Y / C separation circuit is supplied to the input terminal 10. It is supplied to the chroma decoder 11.

This chroma decoder 11 has an input terminal 10
The chroma signal C (carrying color signal) is decoded to obtain color difference signals RY and BY.

Color difference signal R from the chroma decoder 11
-Y and BY are field noise reducer 12 respectively.
After noise reduction processing has been performed by 13 and 13, they are respectively supplied to the chroma encoder 14.

The chroma encoder 14 encodes the color difference signals RY and BY from the field noise reducers 12 and 13 to obtain a chroma signal C, and the chroma signal C is added via an output terminal 15 to, for example, an adding circuit. And component output terminals. Here, in the addition circuit, addition with the luminance signal Y is performed to form a composite color video signal, which is supplied to, for example, a composite output terminal.

Next, the field noise reducer will be described with reference to FIG. In FIG. 5, reference numeral 16 is an input terminal to which the chroma signal C is supplied.
The chroma signal C is supplied to the subtraction circuits 17 and 20, respectively, via.

A limiter circuit 22 limits the voltage information of the subtraction result signal supplied from the subtraction circuit 20 through the low-pass filter 21. The limiter circuit 22 is, for example, a ROM provided with a coefficient k.
(That is, it is also a coefficient unit). The signal from the limiter circuit 22 is supplied to the subtraction circuit 17.

Reference numeral 18 denotes a field memory. By using this field memory 18, the chroma signal at the present time and the chroma signal one field before can be subtracted.

The voltage data Vin of the chroma signal C from the input terminal 16 is subtracted by the subtraction circuit 20 from the voltage data Vd read from the field memory 18,
Further, the coefficient k is multiplied by the low-pass filter 21 and the limiter circuit 22, and the result is supplied to the subtraction circuit 17.

Then, the subtractor circuit 17 causes the chroma signal C
The voltage data from the limiter circuit 22 described above is subtracted from the voltage data of, and the data is written in the field memory 18, and the written signal is output from the output terminal 19.

When the above-mentioned calculation for noise reduction is made into an expression, the voltage Vout of the output terminal 19 = the voltage V of the chroma signal
in-k (voltage data Vin of chroma signal C-voltage data Vd) = (1-k) voltage data Vin + of chroma signal
k · voltage data Vd.

That is, the field memory 18 subtracts the chroma signal C one field before and the chroma signal C at the present time, and the subtraction result signal is multiplied by the coefficient k to extract the noise component of the chroma signal. And this coefficient k
The subtraction result signal multiplied by is subtracted from the current chroma signal C, and this subtraction result signal is again generated in the field memory 1
8 and is supplied to the output terminal 19.

Here, assuming that the chroma signal C supplied to the input terminal 16 is data sampled at 4 fsc which is accurately locked to the subcarrier,
The digital chroma decoder is very easy to implement.

That is, as shown in FIG. 3 in which each arrow is a sampling point, the sampling point of the burst signal (FIG. 3B) is a clock of 4 fsc (FIG. 3A).
There is one sampling point for every four sampling points.

The sampling point of the color difference signal RY (FIG. 3C) is shifted by 1 from each sampling point with respect to the clock signal of the burst signal, and is 4 fsc.
There is one sampling point for every four sampling points of the clock, and the color difference signal B-
The sampling point of Y (FIG. 3D) is shifted by 2 from each sampling point for the clock signal of the burst signal, and there is one sampling point for every four sampling points of the clock of 4 fsc.

As can be seen from this, the color difference signals R-Y and B-Y are written alternately in the field memory 18 and the field memory 18 described above.
Can be considered equivalent to dedicating the color difference signals R-Y and B-Y.

From the above, the field noise reducer described with reference to FIG. 5 can be constructed as shown in FIG.

6, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 6, the chroma decoder 24 is arranged between the connection points of the input terminal 16 of the field noise reducer described in FIG. 5 and the positive input terminal of the subtraction circuit 17 and the positive input terminal of the subtraction circuit 20. At the same time, the chroma encoder 25 is arranged between the connection point of the output terminal 19 and the output terminal of the field memory 18 and the negative side input terminal of the subtraction circuit 20.

In this way, the chroma signal C from the input terminal 16 is supplied to the chroma decoder 24 for the color difference signals R-Y and B.
-Y are decoded respectively.

Then, these color difference signals RY and BY
Is subtracted from the color difference signals R-Y and B-Y one field before, and the subtraction result signal is multiplied by the coefficient k by the low-pass filter 21 and the limiter circuit 22 to obtain noise of the color difference signals R-Y and BY. The components are extracted. Then, the subtraction result signal multiplied by the coefficient k is subtracted from the color difference signals RY and BY at the present time, and the subtraction result signal is written in the field memory 18 again and supplied to the chroma encoder 25.

The color difference signals R-Y and B-Y supplied to the chroma encoder are encoded into a chroma signal C. Then, the chroma signal C is supplied to the output terminal 19.

A reproducing apparatus in which the memory used for the field noise reducer as described above can also be used as the memory used for scanning or reproducing a still image is shown in FIG.

The reproducing apparatus of this example will be described below with reference to FIG. 1. The portions corresponding to those in FIGS. 4 to 7 are designated by the same reference numerals and the detailed description thereof will be omitted.

In FIG. 1, 27 is a switch, and the movable contact 27c of this switch 27 is connected to one and the other fixed contacts 27a or 27b by a control signal from the video disc player main body (not shown). ..

That is, for example, during normal reproduction, scanning and still image reproduction, the control signal (see FIG. 2C) becomes "1", the movable contact 27c of the switch 27 is connected to one fixed contact 27a, and noise is reduced. The control signal becomes "0", and the movable contact of the switch 27 is connected to the other fixed contact 27b.

Reference numeral 3 denotes the switch described with reference to FIG. 7. The other fixed contact of this switch is connected to the fixed contact 28a of the switch 28, and the movable contact 2 of this switch 28 is connected.
8b is connected to the negative side input terminal of the subtraction circuit 29.

The output terminal of the subtraction circuit 29 is connected to the movable contact 30b of the switch 30.
The fixed contact 30a is connected to the input end of the low-pass filter 21.

Further, 28 and 30 are switches respectively, and these switches 28 and 30 are respectively turned on when the control signal from the video disc player main body (see FIGS. 2E and 2F) is "1", and the control signal is "1". When it is 0 ", it is turned off.

That is, when scanning or reproducing a still image,
The control signal becomes "0", the switches 28 and 30 are turned off, and when the noise is reduced, the control signal becomes "1".
And the switches 28 and 30 are turned on.

Next, the operation of the above reproducing apparatus will be described with reference to FIG.
The timing chart will be described. First, when the video disc player main body (not shown) is in normal reproduction, the mode signal is at high level "1" as shown in FIG. 2B, and at the time of still image reproduction or scanning, it is at low level "0". ..

At this time, the control signal shown in FIG. 2C has a low level "0" for noise reduction, and has a high level "1" for normal reproduction, still image reproduction and scanning.

During normal reproduction, the above-mentioned control signal (FIG. 2C) becomes the high level "1", so the switch 2
The movable contact 27c of No. 7 is connected to the fixed contact 27a.

At the same time, the control signal shown in FIG. 2D becomes high level "1", so that the movable contact 3c of the switch 3 is connected to the fixed contact 3a.

Furthermore, since the control signals shown in FIGS. 2E and 2F are low level "0", the switches 28 and 30 are
Are both off.

Thus, the video signal from the video disc player main body is passed through the switch 27 to Y / C.
It is supplied to the separation circuit 4.

The Y / C separation circuit 4 separates the luminance signal Y and the chroma signal C, and the luminance signal Y passes through the delay circuit 5 for time adjustment with the chroma signal C and the component output terminal 8 and the addition circuit. 6 is supplied.

On the other hand, the chroma signal C is sent to the chroma decoder 24.
Is supplied to the chroma encoder 25 through the subtraction circuit 17 and is decoded by the chroma decoder 24 into color difference signals RY and BY. Chroma encoder 2
The chroma signal C is converted into a chroma signal C by 5 and supplied to the component output terminal 7 and the adder circuit 6.

The luminance signal Y and the chroma signal C respectively supplied to the adder circuit 6 are added by the adder circuit 6 into a color video signal, which is supplied to the composite output terminal 9.

Now, when the main body of the video disc player reproduces still images or scans, the above-mentioned control signals (see FIG.
Since C) becomes the high level "1", the movable contact 27c of the switch 27 is connected to the fixed contact 27a.

Since the control signal (FIG. 2D) becomes low level "0", the movable contact 3c of the switch 3 is connected to the fixed contact 3b.

On the other hand, since the control signals shown in FIGS. 2E and 2F are low level "0", both the switches 28 and 30 are turned off.

Then, the video signal is supplied to the field memory 2 via the switch 27, and the video signal is stored in the field memory 2.

The video signal stored in the memory 2 is supplied to the Y / C separation circuit 4 via the switch 3.
Since the subsequent process is the same as that in the above-described normal reproduction, the description thereof will be omitted.

Next, the case of noise reduction will be described. In this case, since the above-mentioned control signal (FIG. 2C) becomes the low level "0", the movable contact 27c of the switch 27 will be described.
Is connected to the fixed contact 27b.

On the other hand, since the control signal (FIG. 2D) becomes the high level "1", the movable contact 3c of the switch 3 is connected to the fixed contact 3a.

Further, after the control signal (FIG. 2C) becomes low level "0", the control signal (FIGS. 2E and 2F) becomes high with a delay of one cycle of the reproduction vertical synchronizing signal shown in FIG. 2A. Since the level is "1", the switches 28 and 30 are turned on one field later than when the switch 27 is switched.

Thus, in the first one field, the video signal supplied to the input terminal 1 is supplied to the Y / C separation circuit 4 via the switch 3, and the Y / C separation circuit 4 causes the luminance signal Y and The chroma signal C is separated.

The luminance signal Y is supplied to the component output terminal 8 and the adding circuit 6 via the delay circuit 5.

On the other hand, the chroma signal C is supplied to the chroma decoder 2
4 and decoded into color difference signals R-Y and B-Y. The color difference signals R-Y and B-Y are supplied to the fixed contact 27b of the switch 27 and the chroma encoder 25 via the adder circuit 17.

The color difference signals R-Y and B-Y supplied to the chroma encoder 25 are converted into the chroma signal C by the chroma encoder 25 and then supplied to the component output terminal 7 and the adder circuit 6.

The luminance signal Y and the chroma signal C supplied to the adder circuit 6 are converted into color video signals and supplied to the composite output terminal 9.

On the other hand, the color difference signals RY and BY supplied to the fixed contact 27b of the switch 27 are supplied to the switch 2
It is stored in the field memory 2 via 7.

When the above-mentioned first field is completed and the next second field is reached, the control signals shown in FIGS. 2E and 2F are set to the high level "1", so that the switches 28 and 30 are turned on.

Thus, the Y / C separation circuit 4 has the following 2
The video signal of the field is supplied, the video signal is separated into the luminance signal Y and the chroma signal C, and the chroma signal C is converted into the color difference signals RY and BY by the chroma decoder 24. Then, the color difference signals RY and BY are supplied to the subtraction circuits 17 and 29, respectively.

At the same time, the color difference signals R-Y and B-Y read from the field memory 2 are supplied to the subtraction circuit 29 via the switch 28.

The subtraction circuit 29 subtracts the color difference signals RY and BY of the first field from the color difference signals RY and BY of the second field, respectively.

The subtraction result from the subtraction circuit 29 is passed through the switch 30, the low-pass filter 21 and the limiter 22 to be a noise component, and this noise component is supplied to the subtraction circuit 17.

In this subtraction circuit 17, the noise component is subtracted from the color difference signals RY and BY of the second field.

The noise-reduced color difference signals R-Y and B-Y are supplied to the chroma encoder 25, and after being converted into the chroma signal C by the chroma encoder 25,
It is supplied to the component output terminal 7 and the adder circuit 6.

Then, in the adder circuit 6, the chroma signal C is added to the luminance signal Y to form a color video signal with reduced noise, which is supplied to the composite output terminal 9.

Thus, in the case of noise reduction, the color video signal from the composite output terminal 9 is sent to an external monitor television or the like via another output circuit or the like of the video disc player body (not shown). When supplied and projected on the screen, noise is reduced and a very high quality image is displayed.

As described above, in this example, as a memory for reducing noise of the chroma signal during normal reproduction without using the memory used for scanning or still image reproduction in the video disc player. Since it is used, the noise of the color signal can be reduced with a simple structure and low cost. Further, since the configuration can be simplified in this way, it is also easy to integrate the Y / separation circuit 4 and the noise reduction portion of the chroma signal C described above into an integrated circuit.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0086]

According to the present invention described above, in the case of reducing the noise of the color signal, the color signal from the second subtracting means is stored in the memory, and the color signal from the separating means is read from this memory. Since the noise component extracted from the subtraction result signal obtained by subtracting the color signal is subtracted from the color signal from the separating means, a new memory is not added, thereby simplifying the configuration and reducing the price. There is an advantage that it is possible to provide a reproducing apparatus that can reduce the noise of color signals at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a reproducing apparatus of the present invention.

FIG. 2 is a timing chart for explaining an embodiment of the reproducing apparatus of the present invention.

FIG. 3 is an explanatory diagram for explaining an embodiment of the reproducing apparatus of the present invention.

FIG. 4 is a block diagram for explaining an embodiment of the reproducing apparatus of the present invention.

FIG. 5 is a block diagram for explaining an embodiment of the reproducing apparatus of the present invention.

FIG. 6 is a block diagram for explaining an embodiment of the reproducing apparatus of the present invention.

FIG. 7 is a block diagram provided for explaining an example of a conventional reproducing apparatus.

[Explanation of symbols]

 2 field memory 3, 27, 28, 30 switch 4 Y / C separation circuit 5 delay circuit 6 addition circuit 17, 29 subtraction circuit 21 low-pass filter 22 limiter circuit 24 chroma decoder 25 chroma encoder

Claims (1)

Claims: 1. A video signal is reproduced from a recording medium, a video signal reproduced from the recording medium is stored in a memory, and the video signal read from the memory is output as a still image. In the reproducing apparatus, the separation means for separating the video signal into the luminance signal and the color signal, and the first subtraction means for subtracting the signal read from the memory from the color signal from the separation means, Noise subtraction means for extracting the noise component of the color signal from the subtraction result signal from the first subtraction means, and second subtraction means for subtracting the noise component from the color signal from the separation means, In the case of reducing the noise of the color signal, the color signal from the second subtracting means is stored in the memory, and the color signal read from the memory is subtracted from the color signal from the separating means. A reproducing apparatus characterized in that the noise component extracted from the subtraction result signal is subtracted from the color signal from the separating means.