JPH03167996A - Video signal processor - Google Patents

Abstract

PURPOSE:To easily identify that an output signal is a color video signal already processed of EDTV by providing identification signal insertion means and superimposing a prescribed identification signal onto a color video signal processed by level compensation processing for a vertical blanking period and outputting the result. CONSTITUTION:An identification signal Sid outputted from an identification generating circuit 15 is fed to an adder 14 via a gate 16. On the other hand, a video signal Sed is fed from a terminal 11 to a synchronizing separator circuit 17, in which horizontal and vertical synchronizing signals are separated and fed to a gate pulse generating circuit 18, from which a gate pulse in a proper timing is formed and fed to the gate 16 as a control signal. Thus, a sinusoidal wave signal of a chrominance subcarrier frequency is inserted as the identification signal Sid to, e.g. 15th horizontal scanning period H15 of each vertical blanking period in addition to a burst signal Sb. Then the video signal Sed with the identification signal Sid inserted thereto is led from an output terminal 12 and recorded on a VTR 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a video signal processing device suitable for EDTV video signals.

[Summary of the Invention] The first invention provides a video signal in which an NTSC color video signal and a high-frequency luminance signal subjected to predetermined level compensation processing are combined to obtain an EDTV color video signal. In the signal processing device, an identification signal insertion means is provided, and the ED
By superimposing a predetermined identification signal on the vertical blanking period of the TV color video signal and outputting it, the output signal becomes EDT.
This is to ensure that it is identified as a V-format color video signal.

The second invention provides an NTSC color video signal;
In a video signal processing device that obtains an EDTV color video signal by combining a high-frequency luminance signal that has undergone predetermined level compensation processing, a predetermined identification signal in a color video signal manually input from the outside is detected. It is possible to prevent over-compensation of the EDTV color video signal by providing an identification signal detection means for detecting the signal, and combining the level-compensated high-frequency luminance signal with the NTSC color video signal based on its detection output. It is designed to prevent this.

[Conventional technology] As is well known, television broadcasting using the current NTSC system has been in operation for over 30 years, and in recent years the cathode ray tubes of television receivers have become larger and brighter, and furthermore, VTRs and
With the improvement in image quality of other signal sources such as video discs, the drawbacks of the NTSC system have become more noticeable.

In other words, in the NTSC system, the constant brightness principle does not hold due to gamma correction on the transmitting side, and since the color signal band is limited and transmitted, brightness details deteriorate in high chroma parts of the received image. . Furthermore, as the brightness of the cathode ray tube increases, the effective gamma value increases, and the overall photoelectric conversion characteristics including the camera system deteriorate, especially in dark areas of the image.

For this reason, various studies have been conducted on techniques for improving the image quality of television broadcasting, and gamma correction compensation (constant brightness signal Image quality improvement technologies on the transmitting side, such as processing (commonly known as Y3) and adaptive emphasis (commonly known as Sl), were taken up and put into practical use as the first generation of the E'DTV system (commonly known as Clear Vision).

Constant brightness signal processing is a process in which a portion of the high-frequency brightness signal corresponding to the deterioration is compensated for on the transmitting side. In addition, adaptive emphasis processing compensates for the high-frequency luminance signal strength on the transmitting side by adding a certain amount of the luminance signal to the compensation circuit so that the detail components increase in darker areas. Applied at the signal stage.

These techniques can improve image quality by about 1.5 ranks on the evaluation scale based on CCIR's 7-level relative comparative evaluation method.

Reference: Magazine “Broadcasting Technology” Volume 42, No. 4, 198
Published in April 2009, etc. [Problem to be solved by the invention] By the way, on the transmission (image transmission) side, component-type VTRs are often used for program production and transmission, and these VTRs include: The EDTV video signal as described above is also recorded.

However, when the EDTV video signal recorded on the VTR is played back and subjected to the EDTV processing again, a problem arises in that overcompensation occurs and the image quality deteriorates.

In view of the above, an object of the present invention is to provide a video image that can be reliably identified as an EDTV video signal, and that can also reliably prevent overcompensation of the EDTV video signal and maintain high image quality. The purpose is to provide a signal processing device.

[A Thousand Steps to Solve the Problem] The first aspect of the present invention is to combine a luminance signal, a chrominance signal, and a high-frequency luminance signal that has undergone predetermined level compensation processing to generate a high-quality color video signal Sed. In the video signal processing device, an identification signal insertion means (10) is provided, and a predetermined identification signal Sid is superimposed on the vertical retrace period of a color video signal subjected to level compensation processing and output. This is a video signal processing device.

A second aspect of the present invention is a video signal processing device that obtains a high-quality color video signal Sed by synthesizing a brightness signal, a color signal, and a high-frequency brightness signal that has been subjected to predetermined level compensation processing. , identification signal detection means (
50), and the high-frequency luminance signal subjected to level compensation processing is combined with the luminance signal and the color signal based on the detection output of the identification signal detection means.

[Operation] According to this configuration, it is reliably identified as an EDTV video signal, and over-compensation of the EDTV video signal is reliably prevented, thereby maintaining high image quality.

[Embodiment 1] Hereinafter, an embodiment of the video signal processing apparatus according to the present invention will be described with reference to FIGS. 1 to 3.

First, FIG. 1 shows the structure of the main parts of a first embodiment of the present invention.

In FIG. 1, (10) is an identification signal insertion circuit, and the EDTV video signal Sed, which has been subjected to the constant brightness signal processing and adaptive emphasis processing as described above, is supplied to the input terminal (1l). . Input terminal (1l) and output terminal (
Adder (1) is connected to the transmission line (main line) (13) between
4) is inserted. (l5) is an identification signal generation circuit, and the identification signal Si output from this generation circuit (15)
d is supplied to the adder (14) via the gate (16). On the other hand, the video signal Sed is supplied from the terminal (11) to the sync separation circuit (17) and is separated by this circuit (17). The horizontal and vertical synchronizing signals thus generated are supplied to a gate pulse generation circuit (18), which generates gate pulses at appropriate timing and supplied to the gate (16) as control signals.

As a result, as shown in FIG. 2, during each vertical retrace period,
For example, in the 15th horizontal scanning period (}115), a sine wave signal with a color subcarrier frequency fsc is inserted as the identification signal Sid, separately from the burst signal sb. Then, the video signal Sed into which this identification signal Sid has been inserted is derived from the output terminal (12) and recorded on the VTR (1).

Note that the identification signal Sid is the current component type VT.
Frequency f in the gray level part, as used in R
An SC sine wave signal may be inserted.

Next, FIG. 3 shows the structure of a second embodiment of the present invention.

In Fig. 3, (20) is an NTSC color encoder, which has input terminals (21r) and (21g).
．． (2lb), for example, l sets of component video signals R, G, B from the camera (2) are supplied, and each is supplied to the matrix circuit (23) via the gamma correction circuit (22), and the luminance Signal Y1 and a pair of color signals 1
, Q are expressed. The luminance signal Yl is sent to the adder (24)
After that, the color signal 1. Q is a low-pass filter (
25) and (26), both of them are connected to the multiplexing circuit (27).
).

(30) is a constant brightness signal processing circuit, which has an input terminal (
21r). The component video signals R, G, B from (21g) and (2lb) are connected to the matrix circuit <3l
) to form a luminance signal YO. This luminance signal YO is gamma-corrected in a gamma correction circuit (32) to become a luminance signal Y7, passes through a low-pass filter (33), becomes a luminance signal Y7L, and is supplied to a divider (34). On the other hand, the luminance signal Yl output from the matrix circuit (23) is commonly supplied to the subtracter (35) and the low-pass filter (36), and the output YIL of the low-pass filter (36) is supplied to the divider (34) and the low-pass filter (36). The output YIB of the subtracter (35) is commonly supplied to the subtracter (35), and the output YIB of the subtracter (35) is supplied to the multiplier (37).
is supplied to

A calculation of Y7L/YIL is performed in the divider (34), and the output of the divider (34) is supplied to the multiplier (37). The output of this multiplier' (37) is supplied to the E side contact of the changeover switch (39) via the adder (38).

(40) is an adaptive emphasis circuit, and the luminance signal Y1 output from the matrix circuit (23) is commonly supplied to a high-pass filter (41) and a low-pass filter (42). The output of the high-pass filter (41) is supplied to the emphasis circuit (43), and the output of the low-pass filter (42) is supplied to the control circuit (4'4).
The output of 44) is supplied to an emphasis circuit (43), and the emphasis characteristic of this circuit (43) is controlled according to the output level of the low-pass filter (42). The output of the emphasis circuit (43) is then supplied to the adder (38). As mentioned above, the constant brightness signal processing circuit (30) and the adaptive emphasis circuit (40) are both well known, and various modifications are possible in addition to the configuration shown in FIG. 3.

In the second embodiment, an identification signal detection circuit (50) is provided to supply the luminance signal Y1 outputted from the matrix circuit (23), and generate an appropriate identification signal Sid as shown in FIG. It is detected whether it is included in the luminance signal YI.

In the case of the component video signal from the camera (2), the EDTV processing has not yet been performed and the identification signal Sid is not included in the brightness signal Yl, so the switch (39)
The connection state is as shown by the solid line, and the outputs of the constant brightness signal processing circuit (30) and the adaptive emphasis circuit (40) are combined with the brightness signal Yl, and EDTV processing is performed.

In addition, the reproduced component video signal from VTR (1) has already been subjected to EDTV processing, and the identification signal Si
d is detected, the detection output of the detection circuit (50) switches the connection state of the suinochi (39) as shown by the broken line, and the constant brightness signal processing circuit (30) and the adaptive emphasis circuit (40) The synthesis route for the output of is blocked,
Overcompensation due to redundant EDTV processing is reliably prevented.

Note that in the above embodiment, the component video signal is R.
. It may also be in the form Y, BY.

[Effect of the invention] As detailed above, according to the first invention, the EDTV
Since a predetermined identification signal is superimposed and output during the vertical retrace period of the converted color video signal, the output signal is
A video signal processing device that can identify a DTV-converted color video signal is obtained.

According to the second aspect of the invention, a predetermined identification signal in a color video signal inputted from the outside is detected, and based on this detection output, a high-frequency luminance signal subjected to level compensation processing is converted into a high-frequency luminance signal according to the NTSC system. Since it is made to match the color video signal, a video signal processing device that can reliably prevent overcompensation of the EDTV color video signal can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of the main parts of the first embodiment of the video signal processing device according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the main parts of the first embodiment of the present invention. Figure, 3rd
The figure is a block diagram showing the structure of an embodiment of the video signal processing device according to the second aspect of the present invention. (10) is an identification signal insertion circuit, (15) is an identification signal generation circuit, (30) is a constant brightness signal processing circuit, (4o) is an adaptive emphasis circuit, and (50) is an identification signal detection circuit. Agent Hidemori Matsukuma Figure 1 Figure 2

Claims (1)

[Claims] 1. A video signal processing device that obtains a high-quality color video signal by synthesizing a luminance signal, a chrominance signal, and a high-frequency luminance signal that has undergone predetermined level compensation processing, 1. A video signal processing device, comprising: an identification signal insertion means for superimposing and outputting a predetermined identification signal in a vertical retrace period of the color video signal subjected to the level compensation process. 2. In a video signal processing device that synthesizes a brightness signal, a color signal, and a high-frequency brightness signal that has undergone predetermined level compensation processing to obtain a high-quality color video signal, the color input from the outside is An identification signal detection means for detecting a predetermined identification signal in the video signal is provided, and based on the detection output of the identification signal detection means, the high-frequency luminance signal subjected to the level compensation processing is combined with the luminance signal and color signal. A video signal processing device characterized in that: