JPH118861A - Video signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record the input signals in a small memory capacity with no deterioration of the signal characteristics by recording the signals in a field memory without deteriorating the luminance signal band for the composite TV signals not deteriorating the chrominance signal band for the RGB signals. SOLUTION: Receiving the input switch signal, an input selector 2 and switches 12a, 12b and 12c operate. If the input signals are composite TV signals, the RGB signals which undergone the Y/C separation and chroma decoding via an RGB decoder 1 are selected, undergo the AD conversion and then are converted into the luminance/chrominance signals by an RGB luminance color difference conversion circuit 4. These luminance/chrominance signals are successively converted into progressive signals and recorded in a field memory 6. In a read mode, the progressive signals are successively connected again into the luminance/chrominance signals, converted into the RGB signals and outputted. In regard to the RGB signals, a progressive scan conversion circuit 10 decreases the number of bits of only the RB signals with no decrease of the number of bits of the G signal. The RGB signals are stored in the memory 6. Meanwhile, the RGB signals are made into the luminance/chrominance signals by a progressive scan inverse conversion circuit 11 and outputted.

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 for performing A / D conversion of a composite TV signal or an RGB signal inputted from the outside and writing / reading data to / from a field memory.

[0002]

2. Description of the Related Art A conventional video signal processing apparatus will be described below.

FIGS. 6 and 7 show the configuration of a conventional video signal processing apparatus. In FIG. 6, reference numeral 1 denotes an R for converting a composite TV signal input from the outside into an RGB signal.
A GB decoder 2, an input selector for switching between the output of the RGB decoder 1 and an externally input RGB signal, an AD converter for AD converting the RGB signal of the input selector output, and a luminance and color difference conversion of the AD converted RGB signal RGB-luminance / chrominance signal conversion circuit for converting the signals into 5 signals, a progressive scan conversion circuit for transforming the luminance / color difference signals into a progressive scan signal, 6 a field memory for recording sequentially scanned signals, 7 a field memory A progressive scanning reverse conversion circuit for converting the read progressive scanning signal into a luminance / color difference signal, 8
Is a luminance / color difference for converting a luminance / color difference signal into an RGB signal.
It is an RGB conversion circuit.

In FIG. 7, an RGB decoder 1, an input selector 2, and an AD converter 3 are the same as those in FIG.
This is a field memory for recording GB signals.

[0005] The operation of the conventional video signal processing device configured as described above will be described below.

First, the case where the luminance / color difference signals shown in FIG. 6 are recorded in a memory by sequential scanning will be described. The composite TV signal input from the outside is subjected to Y / C separation and chroma decoding by one RGB decoder to be converted into RGB signals.
The RGB signal and the RGB signal input from the outside are selected by one of the two input selectors into RGB signals, and AD converted by the AD converter 3. Next, in the RGB-luminance / color difference conversion circuit 4, Y = 0.3 · R + 0.59 · G + 0.11 ·
An arithmetic operation B is performed to generate a luminance signal Y, which is used to generate RY and GY color difference signals. FIG. 8A shows a block diagram of this circuit. Next, dot-sequential conversion is performed by the sequential conversion circuit 5 to output signals RY, Y, BY, Y,. This signal passes through a field memory 6, a progressive scanning reverse conversion circuit 7, and a luminance / color difference-RGB conversion circuit 8, and
Obtain the B signal. FIG. 8B is a block diagram of a luminance / color difference-RGB conversion circuit.

In the case of FIG. 7, the RGB signals obtained by the AD conversion by the AD converter 3 are directly written into the field memory and read out to obtain the RGB signals.

[0008]

FIG. 9 shows the timing of dot-sequential conversion after the RGB signals are converted into luminance / color difference signals in the case of the conventional configuration example 1 of FIG.
Will be described. FIG. 9A shows a sample clock. As shown in FIG. 9C, the luminance signal Y and the chrominance signal R having the same cycle as the RGB signal are obtained for the RGB signals simultaneously sampled at twice the cycle of the sample clock as shown in FIG. 9B.
-Y and BY are obtained, and a sequential scanning signal shown in FIG. 9D is obtained.

Here, the sampling period of the luminance signal is the same as the sampling period of the RGB signal, but the sampling period of the color difference signal is twice the sampling period of the RGB signal. Therefore, by performing the sequential scanning, the resolution of the luminance signal is not reduced, but the resolution of the color signal is reduced by half. In the case of a composite TV signal, the luminance signal band is about 4 MHz and the color difference signal band is less than half of the luminance signal band. Therefore, if the luminance signal band can be secured at a sample rate, even if the color signal band is reduced by half by sequential scanning. No problem. However, in the case of an RGB signal input, an RGB signal input from the outside is assumed to have a color resolution higher than that of the composite TV signal and a color gradation lower than that of the composite TV signal. There is a problem that the resolution is reduced to the level of a composite TV signal.

The conventional RG shown in FIGS.
B—an example of a luminance / color difference conversion circuit, in which luminance Y, color difference RY
The arithmetic circuit for obtaining the BY signal includes a multiplier, and has a problem that the circuit scale is increased.

On the other hand, in the case of the conventional configuration example 2 in which the memory is recorded in RGB in FIG. 7, the amount of memory for recording one field is larger than in the conventional configuration example 1 in FIG. This will be described with reference to FIG. In the case of sequential printing, assuming that one pixel has data of k bits of a Y signal and k bits of a color difference signal as shown in FIG. 10A, the data amount of m pixels horizontally and n pixels vertically is 2.multidot. It has km · m · n bits. On the other hand, R
In the case of the GB recording, assuming that each pixel has RGB data of k bits as shown in FIG. 10B, the data amount of horizontal m pixels and vertical n pixels is 3 kmm n And 1.5 times the memory capacity for sequential recording.

In the case of a composite TV signal input, R
The RGB signal subjected to the GB decoding and AD conversion has the same band as the luminance signal at the time of sequential scanning, but the original color difference signal has only a band that is less than half of the luminance signal.
The signal will have redundancy. That is, composite T
In the case of the V signal, there is a problem that an extra memory is used to record redundant data.

The present invention solves the above-mentioned conventional problems. In the case of a composite TV signal input, feed memory recording is performed by sequential scanning of luminance / color difference signals as in the past, and R
It is an object of the present invention to provide a video signal processing device capable of recording RGB signals in a field memory with the same memory capacity as in the case of sequential scanning of a luminance / color difference signal in the case of a GB signal input.

[0014]

In order to achieve the above object, a video signal processing apparatus according to the present invention converts RGB signals into luminance / color difference signals using a simplified arithmetic circuit, and sequentially scans them into a field memory. It has a configuration in which a circuit for recording and a circuit for recording in the field memory can be switched through a sequential scanning circuit for reducing the memory capacity without changing the RGB signals.

According to this configuration, the recording method of the field memory can be switched between an input signal of a composite TV signal and an RGB signal. In the case of a composite TV signal, the luminance signal band is not reduced, and in the case of an RGB signal, the color signal band is not changed. And field memory recording can be performed with the same memory capacity as the conventional sequential scanning method of luminance / color difference signals.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides an RG for converting a composite TV signal into an RGB signal.
A B decoder, an input selector for switching between the RGB decoder output and the RGB signal input, an AD converter for AD converting an analog RGB signal of the input selector output, and converting the AD converted RGB signal into a luminance and color difference signal. An RGB-luminance / color difference signal conversion circuit, a sequential conversion circuit for converting a luminance / color difference signal into a sequential scanning signal, a sequential inverse conversion circuit for converting the sequential scanning signal into a luminance / color difference signal,
Return luminance / color difference signal to RGB signal Luminance / color difference-RGB
A conversion circuit, a progressive scan conversion circuit for converting an RGB signal into a progressive scan signal, a progressive scan reverse-conversion circuit for converting the progressive scan signal into an RGB signal, a field memory for recording the progressive scan signal, and writing to the field memory Signal R
A switch for switching between a GB signal and a luminance / color difference signal,
A switch that switches between returning the sequential scanning signal read from the field memory to the RGB signal or the luminance / color difference signal in conjunction with the switch, and according to the type of the input signal. By switching the recording method to the field memory, the data amount is reduced without deteriorating the characteristics of each input signal, and the video data is recorded with a small field memory capacity.

According to a second aspect of the present invention, there is provided a switch for switching a write signal to a field memory between an RGB signal and a luminance / color difference signal, and a method for returning a sequential scanning signal read from the field memory to an RGB signal or a luminance / color difference signal. The switch for switching back to the original state can be automatically switched by using a signal for determining whether the input signal is a composite TV signal or an RGB signal, and according to the type of the input signal. It has the function of automatically switching the recording method to the field memory.

According to a third aspect of the present invention, there is provided an RGB-luminance / chrominance signal converter for converting a digitized RGB signal into a luminance signal and a chrominance signal.
This signal is returned to an RGB signal again.
The B conversion is realized by a simplified circuit configuration, and has an effect that the circuit configuration can be simplified.

According to a fourth aspect of the present invention, in a circuit for converting a digitized RGB signal into a sequential scanning signal, only the "G" signal having the greatest effect on luminance does not reduce the number of bits. , "B" comprises a sequential conversion circuit for reducing the number of bits.
This has the effect of reducing the memory capacity when recording the B signal in the field memory.

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a block diagram of a video signal processing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an RGB decoder for converting a composite TV signal input from the outside into RGB signals; An input selector for switching between an output and an RGB signal inputted from the outside, an AD converter for AD converting an RGB signal of an input selector output,
Reference numeral 4 denotes an RGB-luminance / color difference signal conversion circuit for converting the AD-converted RGB signals into luminance and color difference signals, 5 a progressive scan conversion circuit for converting the luminance / color difference signals into progressive scan signals, and 6 a progressively scanned signal. A field memory for recording, 7 a sequential scanning reverse conversion circuit for converting a sequential scanning signal read from the field memory into a luminance / color difference signal, 8 a luminance / color difference-RGB conversion circuit for converting the luminance / color difference signal to an RGB signal, 10 Is a progressive scan conversion circuit for sequentially converting RGB signals, 11 is a progressive scan reverse conversion circuit for converting progressive scan signals read from the field memory into RGB signals, 12
(A), (b) and (c) are switches for switching between a recording signal system for the field memory and an RGB output signal.

The operation of the video signal processing device configured as described above will be described. First, composite T
In the case of a V input signal, the RGB decoder 1 separates the Y / C signal
The chroma-decoded RGB signal is selected by the input selector 2, AD-converted into k bits of RGB by the AD converter 3, and the luminance-Y and chrominance R are converted by the RGB-luminance / chrominance conversion circuit 4.
-G and BG are each converted to k + 2 bits.

Here, the RGB-luminance / color difference conversion circuit will be described with reference to FIG. Shift register 41
Shifts the k-bit G signal by 1 bit (k +
1) The adder 42 adds the doubled G signal, the k-bit R signal, and the k-bit B signal (k +
2) Obtain a bit luminance signal Y. Further, the k-bit G signal is subtracted from the k-bit R signal by the subtractor 43 to obtain R-G
The subtracter 44 subtracts the k-bit G signal from the k-bit B signal to obtain a BG signal. RG signal and B
The bit length of the -G signal is set to (k + 2) bits with 1-bit redundancy at the top in order to match the Y signal.
This is the operation of the RGB-luminance / color difference conversion circuit.

Next, the progressive scan conversion circuit 5 converts the signal into a progressive scan signal having a k + 2 bit width. This signal is written to and read from the field memory 6 by the switch 12.
(A) and (b) are switched, and the signal read from the field memory is converted by the sequential scanning reverse conversion circuit 7 into a luminance Y and a color difference R-
The signals are converted into G, BG signals, and RGB is obtained by a luminance / color difference-RGB conversion circuit 8.

FIG. 2B illustrates a luminance / color difference-RGB conversion circuit. The RG signal and the BG signal are added by the adder 45, the result is subtracted from the Y signal by the subtractor 46, and the result is shifted by 2 bits by the shift register 47 and multiplied by 1/4 to obtain the G signal. Further, the G signal and the RG signal are added by an adder 48 to obtain an R signal, and the G signal and the BG signal are added by an adder 49 to obtain a B signal. The above is the operation of the luminance / color difference-RGB conversion circuit. And the obtained RG
The B signal is applied to each k-bit R through switch 12 (c)
It outputs a GB signal. Here, the dot sequential scanning timing will be described with reference to FIG.

FIG. 3A shows a sample clock. As shown in FIG. 3B, for the RGB signals simultaneously sampled at twice the cycle of the sample clock, as shown in FIG. 3C, a luminance signal Y and a color difference signal R having the same cycle as the RGB signals.
-G and BG are obtained to obtain the sequential scanning signal shown in FIG. Here, the sampling period of the luminance signal is the same as the sampling period of the RGB signal, but the color difference signal is the same as the sampling period of the RGB signal.
The sample period is doubled. Therefore, the resolution of the luminance signal does not decrease by performing the dot sequential scanning, but the resolution of the color signal is reduced by half. In the case of a composite TV signal, the luminance signal band is about 4 MHz and the chrominance signal band is less than half of the luminance signal band. No problem. This is the same as conventional field memory recording by point sequential scanning. The above is the operation of the present video signal processing apparatus in the case of composite TV signal input.

Next, in the case of an RGB signal input, an RGB input signal is selected by the input selector 2,
A / D conversion is performed for each of k bits of GB. Next, the progressive scan conversion circuit 10 converts the signal into a progressive scan signal having a k + 2 bit width. The switches 12 (a) and 12 (b) are switched so that this signal is written to and read from the field memory 6, and the signal read from the field memory is converted by the progressive scan reverse conversion circuit 1
In step 1, RGB is obtained, and an RGB signal is output through the switch 12 (c). Here, referring to FIG.
Will be described. FIG. 4A shows a sample clock. As shown in FIG. 4B, the lower bits of the R and B signals are truncated to k / 2 + 2 bits for a k-bit RGB signal sampled simultaneously with a cycle twice as long as the sample clock. And FIG. 4 (c)
As shown in FIG. 2, the k bits of G and the upper 2 bits of B are combined into k + 2 bits, the remaining lower bits of B and k / 2 + 2 bits of R are combined into k + 2 bits, .. Are converted into a sequential scanning signal having a k + 2 bit width. The above is the operation of the video signal processing device in the case of RGB signal input.

As described above, according to the present embodiment, RG
By providing a circuit for converting the B signal into a luminance / color difference signal and recording it in the field memory, a circuit for recording the RGB signal in the field memory as it is, and a circuit for switching between these signals according to the input signal, the composite TV input signal is provided. In the case of, the field memory recording of the luminance and chrominance signals can be performed without lowering the resolution of the luminance as before, and in the case of the RGB signal input, the reduced field without lowering the color resolution and the same as when the composite TV signal is input It can be recorded in memory capacity.

(Embodiment 2) FIG. 5 is a block diagram of a video signal processing apparatus according to the present invention. In FIG. 5, reference numeral 1 denotes an RGB decoder for converting a composite TV signal input from the outside into RGB signals; An input selector for switching between the output of the RGB decoder 1 and an externally input RGB signal, an AD converter for AD-converting the RGB signal of the input selector output, and a converter for converting the AD-converted RGB signal into a luminance and color difference signal. RGB-luminance / color difference signal conversion circuit, 5 is a progressive scan conversion circuit for converting a luminance / color difference signal into a progressive scan signal, 6 is a field memory for recording sequentially scanned signals, and 7 is a progressive scan signal read from the field memory. 8 is a sequential scanning reverse conversion circuit for converting a luminance / color difference signal into a luminance / color difference signal, and a luminance / color difference-RGB conversion circuit 8 for converting the luminance / color difference signal into an RGB signal. A circuit 10, a progressive scan conversion circuit for sequentially converting RGB signals, a reference numeral 11, a progressive scan reverse conversion circuit for converting a progressive scan signal read from a field memory into an RGB signal, and 12 (a), (b), and (c), field memories. This switch is used to switch between the recording signal system and the RGB output signal.

The above is the same as the configuration of FIG. The difference from the configuration of FIG. 1 is that the composite input / RGB input determination signal output from the input selector 2
(A), (b) and (c) are automatically switched.

The operation of the video signal processing device configured as described above will be described below. The operation of switching the recording method to the field memory according to the input signal is the same as in the first embodiment. Further, in this configuration, a composite input / RGB input determination signal is output from the input selector 2, and the recording method for the field memory is switched according to the input signal based on the composite input / RGB input determination signal.

As described above, according to the present embodiment, by providing the circuit for switching the recording method to the field memory using the composite input / RGB input determination signal, the recording method to the field memory according to the input signal is provided. Can be automatically switched.

[0032]

As described above, the present invention provides a composite T
In the case of V signal input or RGB signal input, field memory recording can be performed with a reduced capacity, and in the case of RGB signal input, memory recording can be performed so as not to lower the color resolution. Can be

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a video signal processing device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of the RGB-luminance / color difference conversion circuit.

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

FIG. 4

FIG. 5 is a configuration diagram of a video signal processing device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional video signal processing device (conventional configuration example 1).

FIG. 7 is a configuration diagram of a conventional video signal processing device (conventional configuration example 2).

FIG. 8 is a configuration diagram of a conventional video signal processing device (an example of an RGB-luminance / color difference conversion circuit).

FIG. 9 is an explanatory diagram for explaining an operation of a conventional video signal processing device.

FIG. 10

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 RGB decoder 2 input selector 3 AD converter 4 RGB-luminance / color difference conversion circuit 5 progressive scan conversion circuit 6 field memory 7 progressive scan reverse conversion circuit 8 luminance / color difference-RGB conversion circuit 9 field memory 10 progressive scan conversion circuit 11 progressive scan Inversion circuit 12 Changeover switch 41 Shift register 42 Adder 43 Subtractor 44 Subtractor 45 Adder 46 Subtractor 47 Shift register 48 Adder 49 Adder

Claims (4)

[Claims] An RGB decoder for converting a composite TV signal into an RGB signal, and an output of the RGB decoder and an RGB signal.
An input selector for switching between B signal input, an AD converter for AD converting an analog RGB signal output from the input selector, and an RGB-luminance / color difference signal conversion circuit for converting the AD-converted RGB signal into luminance and color difference signals; A progressive scan conversion circuit for converting a luminance / color difference signal into a progressive scan signal, a progressive scan reverse conversion circuit for returning the progressive scan signal to a luminance / color difference signal, and a luminance / color difference-RGB for returning the luminance / color difference signal to an RGB signal A conversion circuit, a progressive scan conversion circuit for converting an RGB signal into a progressive scan signal, a progressive scan reverse-conversion circuit for converting the progressive scan signal into an RGB signal, a field memory for recording the progressive scan signal, and writing to the field memory A switch for switching the signal between an RGB signal and a luminance / color difference signal, and reading from the field memory in conjunction with this switch A video signal processing apparatus characterized by comprising a switch for switching between the sequential return scan signals to or luminance and color difference signals back into RGB signals. 2. A write signal to a field memory is set to RG.
A switch for switching between a B signal and a luminance / color difference signal, and a switch for switching between a sequential scanning signal read from the field memory and returning to an RGB signal or a luminance / color difference signal, are provided when the input signal is a composite TV signal or RGB.
2. The video signal processing apparatus according to claim 1, wherein automatic switching can be performed by using a signal for determining whether the video signal is a signal. 3. An RGB-luminance / chrominance signal converter for converting a digitized RGB signal into a luminance signal and a chrominance signal.
After passing through the field memory, this signal is
2. The video signal processing apparatus according to claim 1, wherein the luminance / color difference signal / RGB conversion circuit for returning to a signal is realized by a simplified circuit configuration. 4. In a circuit for converting a digitized RGB signal into a progressive scan, the number of bits is not reduced only for a "G" signal having the greatest influence on luminance.
2. The video signal processing device according to claim 1, further comprising a sequential conversion circuit for reducing only the number of bits.