JP5337733B2 - Video signal transmission device, transmission video signal generation program, video signal reception device, transmission video signal conversion program, and video signal transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signal transmitting device that prevents a reduction in SN ratio due to compression and expansion of nonlinear conversion while executing constant luminance transmission satisfying constant luminance principle. <P>SOLUTION: The video signal transmitting device 1 includes: a luminance signal generating means 10 for generating a luminance signal by mixing color signals of linear signals; a band limiting means 11 for extracting a signal of a low frequency component from a red signal and a blue signal; a downsampling means 12 for downsampling each of the extracted signals; a nonlinear conversion means 13 for converting each of the downsampled signals and the luminance signal generated by the luminance signal generating means 10 into a nonlinear signal. The nonlinear luminance signal, the low band nonlinear red signal and the low band nonlinear blue signal are used as video signals for transmission. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a video signal transmission device, a transmission video signal generation program, a video signal reception device, a transmission video signal conversion program, and a video signal transmission system according to a video signal transmission technique.

  Conventionally, as a method of transmitting a television video signal, luminance is obtained from an R (red) signal, a G (green) signal, and a B (blue) signal, which are three primary color signals photographed by a camera or electronically generated. A method of generating and transmitting a signal and a color difference signal is used (see Non-Patent Document 1).

Here, with reference to FIG. 13, a conventional technique (conventional technique 1) for transmitting a video signal using a luminance signal and a color difference signal will be described. First, as illustrated in FIG. 13A, the video signal transmitting apparatus 1 </ b> C uses a nonlinear conversion unit (gamma correction unit) 50 to perform gamma correction on the RGB signal that is a linear signal (the gamma characteristic of the reception apparatus 2 </ b> B). By performing the inverse characteristics, a signal is decompressed for a region with a low signal level, and a signal compression (nonlinear compression / decompression processing) is performed for a region with a high signal level. As a result, the RGB signal that is a linear signal is converted into an R ^α G ^α B ^α signal that is a non-linear signal.
Then, the transmission apparatus 1C performs matrix conversion shown in the following equation (1) on the R ^α G ^α B ^α signal that has been gamma corrected by the matrix conversion unit 51, thereby obtaining the luminance signal Y ′ and the color difference signal. Cb ′ and Cr ′ are generated.

Here, r, g, and b are coefficients for generating a luminance signal. For example, in the HDTV signal standard, r = 0.2126, g = 0.7152, and b = 0.0722.
Further, KCB, because kcr is with about twice the dynamic range of the (B α -Y ^') and (R α ^-Y') is the original signal ^{(B (B α), R} (R α)), This is a coefficient for keeping the color difference signals Cb ′ and Cr ′ within the dynamic range.

Then, the transmission device 1C performs band limitation for extracting a low frequency component by the band limiting unit (LPF; low pass filter) 52 with respect to the color difference signals Cb ′ and Cr ′. The pixels are converted to color difference signals Cb ′ _LD and Cr ′ _LD by down-sampling every other pixel in the horizontal direction or horizontal and vertical direction.
As a result, the transmitting apparatus 1C generates signals (Y ′, Cb ′ _LD , Cr ′ _LD ) in the 4: 2: 2 format, 4: 2: 0 format, and the like.
The luminance signal Y ′ and the color difference signals Cb ′ _LD and Cr ′ _LD generated in this way are transmitted to the receiving side.

On the other hand, as shown in FIG. 13B, the video signal receiving device 2C performs upsampling on the color difference signals Cb ′ _LD and Cr ′ _LD by the upsampling means 60 among the received video signals. Thus, the sample number and the pixel structure are returned to the same sample number and pixel structure as the luminance signal Y ′.
Then, the receiving device 2C generates an R ^α G ^α B ^α signal by performing the inverse transformation (inverse matrix transformation) of the equation (1) by the inverse matrix conversion means 61.
Then, the receiving device 2C generates an RGB signal by giving the R ^α G ^α B ^α signal the inverse characteristic of the gamma correction in the nonlinear converting unit 50 of the transmitting device 1C by the linear converting unit 62. If the display device is a display device having a gamma characteristic such as a CRT, the linear conversion means 62 corresponds to the display device, and the R ^α G ^α B ^α signal is obtained as light having passed through the gamma characteristic of the display device. Played.

However, in this method, the matrix conversion unit 51 generates a luminance signal and a color difference signal from the non-linear RGB signal (R ^α G ^α B ^α signal) subjected to gamma correction, and further, the band limiting unit 52 The band of the color difference signal is limited. Therefore, the receiving apparatus 2B has a problem that the luminance information cannot be correctly reproduced when the RGB signal is restored from the luminance signal and the color difference signal. This is because the information for restoring the luminance is transmitted only by the luminance signal for transmission and does not satisfy the constant luminance principle that it is important that the information is not affected by the color signal (see Non-Patent Document 1).
Furthermore, in this method, since the band limitation on the color difference signal is a band limitation on the nonlinear signal, part of the information (harmonic component) included in the nonlinear signal is lost due to the band limitation, and the color information is correct. There is also a problem that it cannot be reproduced.

  In order to solve this problem, the luminance signal is generated from the linear RGB signal, and the band limitation is performed on the linear signal instead of the band limitation on the nonlinear signal. As such a method, there is a method adopted by an analog transmission method (MUSE method) of HDTV (High Definition TeleVision).

Here, with reference to FIG. 14, a transmission method of the MUSE system, which is another method (conventional method 2) for transmitting a video signal using a conventional luminance signal and color difference signal, will be described.
As shown in FIG. 14A, the MUSE transmission device 1D is different from the transmission device 1C described in FIG. 13A in that the nonlinear conversion means 50 is replaced with a matrix conversion means 51, a band limiting means 52, and a down-converter. It is provided in the subsequent stage of the sample means 53.

Further, as shown in FIG. 14B, the MUSE-type receiving device 2D has a linear conversion means 62 arranged before the inverse matrix converting means 61 with respect to the receiving device 2C described in FIG. 13B. The received luminance signal and color difference signal are first converted into linear signals.
That is, in the transmission apparatus 1D, band limitation is performed on the difference signals RY and BY of the R and B signals that are linear signals and the luminance signal Y that is a linear signal, and then gamma correction is performed to perform transmission. The video signal is generated.
As described above, the MUSE transmission method enables constant luminance transmission that satisfies the constant luminance principle.

Supervised by Hideo Kusaka, “Color Image Engineering”, The Institute of Image Information and Television Engineers, Ohmsha, April 25, 1997, pp. 126-129 ITU-R BT.709: Parameter values for the HDTV standards for production and international program exchange

As described above, the conventional method 1 does not satisfy the constant luminance principle, and thus has a problem that luminance information and color information cannot be correctly reproduced on the receiving side.
On the other hand, the conventional method 2 described above can correctly reproduce luminance information and color information as compared with the conventional method 1. However, the conventional method 2 performs nonlinear conversion on the difference signal RY (such as Cr in FIG. 14) and the difference signal BY (such as Cb in FIG. 14). In the case where the signal is large (high saturation portion), conversion for compressing the amplitude is performed.
Therefore, the conventional method 2 has a problem that the signal-to-noise ratio (SN ratio) decreases in the high saturation portion.

  In the conventional MUSE system, the non-linear characteristic of the color difference signal is made gentler than that of the luminance signal, and the amplitude is doubled to suppress a decrease in the SN ratio of the high saturation portion. However, doubling the amplitude in an analog video signal has the problem of increasing the number of bits in the digital video signal and increasing the data amount of the video signal.

  The present invention has been made in view of the above problems, and suppresses a decrease in the S / N ratio caused by compression / expansion of nonlinear conversion (gamma correction) while performing constant luminance transmission that satisfies the constant luminance principle. It is an object of the present invention to provide a video signal transmission device, a transmission video signal generation program, a video signal reception device, a transmission video signal conversion program, and a video signal transmission system.

  The present invention has been made to solve the above-mentioned problems. First, the video signal transmitting apparatus according to claim 1 transmits from the first to third color signals which are input three primary color signals. A video signal transmitting apparatus that generates and transmits a video signal for use includes a luminance signal generating unit, a band limiting unit, a down-sampling unit, and a non-linear conversion unit.

  In such a configuration, the video signal transmission device generates a linear luminance signal that is a linear luminance signal by mixing the color signals of the three primary colors that are linear signals at a predetermined mixing ratio by the luminance signal generation means. Thus, by generating a luminance signal from a linear color signal, it is possible to generate a more accurate luminance signal than when a luminance signal is generated from a non-linear color signal.

  Then, the video signal transmitting apparatus extracts the low frequency component signal from the first color signal and the second color signal by the band limiting unit, and down-samples each extracted signal at a predetermined sampling interval by the down-sampling unit. Sample. Band limiting means and down-sampling means may perform band limiting or down-sampling according to a predetermined frequency or sample ratio in 4: 2: 2 format, 4: 2: 0 format, or the like.

Then, the video signal transmitting apparatus converts the linear luminance signal generated by the luminance signal generation unit by the nonlinear conversion unit to a nonlinear luminance signal by nonlinear conversion, and the low-frequency linear first color signal down-sampled by the down-sampling unit The low-frequency linear second color signal is converted into a low-frequency nonlinear first color signal and a low-frequency nonlinear second color signal, respectively.
The nonlinear luminance signal, the low-frequency nonlinear first color signal, and the low-frequency nonlinear second color signal are transmission video signals.

  A signal obtained by band-limiting the color difference signal such as 4: 2: 2 format or 4: 2: 0 format is equivalent to transmitting only luminance information for the high frequency component, and is a video signal reproduced on the display. Are the low-frequency components of the RGB signal and the high-frequency components of the luminance signal.

  That is, in the video signal transmitting apparatus according to the present invention, the low frequency component of the RGB signal is transmitted by the non-linear luminance signal, the low frequency non-linear first color signal, and the low frequency non-linear second color signal, and the high frequency of the luminance information is transmitted. The component is transmitted by a high frequency component included in the non-linear luminance signal, and satisfies a signal format condition such as 4: 2: 2 format.

  According to a second aspect of the present invention, there is provided a transmission video signal generation program for generating a luminance signal to generate a transmission video signal from first to third color signals that are input three primary color signals. Means, band limiting means, downsampling means, and non-linear conversion means.

In this configuration, the transmission video signal generation program generates a linear luminance signal that is a linear luminance signal by mixing the color signals of the three primary colors that are linear signals at a predetermined mixing ratio by the luminance signal generation unit.
Then, the transmission video signal generation program extracts a low frequency component signal from the first color signal and the second color signal by the band limiting unit, and the sampling signal extracted by the down-sampling unit is a predetermined sampling interval. Downsample with.

The transmission video signal generation program converts the linear luminance signal generated by the luminance signal generation unit by the nonlinear conversion unit to a nonlinear luminance signal by nonlinear conversion, and down-samples the low-band linear first color by the down-sampling unit. The signal and the low-frequency linear second color signal are converted into a low-frequency nonlinear first color signal and a low-frequency nonlinear second color signal, respectively.
The nonlinear luminance signal, the low-frequency nonlinear first color signal, and the low-frequency nonlinear second color signal are transmission video signals.

  Furthermore, the video signal receiving apparatus according to claim 3 is a non-linear luminance signal obtained by nonlinearly converting a luminance signal generated from first to third color signals which are color signals of three primary colors, and the first color signal and the second color signal. A video signal that receives a low-frequency nonlinear first color signal and a low-frequency nonlinear second color signal that are nonlinearly converted after extracting a low-frequency component from the signal, down-sampled, and converting the received color signal into a color signal The receiving apparatus includes a linear conversion unit, a band limiting unit, an upsampling unit, a color signal generation unit, a high-frequency signal generation unit, and a high-frequency signal addition unit.

  In such a configuration, the video signal receiving apparatus converts the non-linear luminance signal into the linear luminance signal by giving the inverse characteristic of the non-linear conversion on the transmission side by the linear conversion means, and converts the low-frequency non-linear first color signal and the low-frequency non-linear signal. The second color signal is converted into a low-frequency linear first color signal and a low-frequency linear second color signal, which are linear signals. Note that the nonlinear luminance signal is obtained by performing nonlinear conversion on the luminance signal generated from the color signal, which is a linear signal, on the transmission side. Therefore, the luminance signal is accurately reproduced by giving the inverse characteristic of this nonlinear conversion. Is done.

Then, the video signal receiving apparatus extracts a low frequency component from the linear luminance signal by the band limiting unit.
In addition, the video signal receiving apparatus has the same number of samples and pixel structure as the linear luminance signal by converting the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means by the up-sampling means. Upsample to
Then, the video signal receiving device includes the low-frequency linear luminance signal extracted by the band limiting device by the color signal generating device, the low-frequency linear first color signal and the low-frequency linear second color signal up-sampled by the up-sampling device, To generate a low-pass linear third color signal.

Further, the video signal receiving apparatus generates a high frequency luminance signal, which is a high frequency component of the linear luminance signal, from the linear luminance signal by the high frequency signal generating means.
Then, the video signal receiving device adds the high-frequency luminance signal to the low-frequency linear first color signal, the low-frequency linear second color signal, and the low-frequency linear third color signal by the high-frequency signal adding means. Accordingly, the video signal receiving apparatus can generate the first to third color signals that are color signals.

  According to a fourth aspect of the present invention, there is provided a non-transitory luminance signal obtained by non-linear conversion of luminance signals generated from first to third color signals which are three primary color signals, the first color signal and the first color signal. The low-frequency non-linear first color signal and the low-frequency non-linear second color signal which are nonlinearly converted after the low-frequency component is extracted from the two-color signal and down-sampled are received as a video signal for transmission and converted into a color signal. Therefore, the computer is configured to function as linear conversion means, band limiting means, upsampling means, color signal generation means, high frequency signal generation means, and high frequency signal addition means.

  In such a configuration, the transmission video signal conversion program converts the non-linear luminance signal to the linear luminance signal by giving the inverse characteristic of the non-linear conversion on the transmission side by the linear conversion means, and reduces the low-frequency non-linear first color signal and the low-frequency non-linear first color signal. The band non-linear second color signal is converted into a low band linear first color signal and a low band linear second color signal, which are linear signals, respectively.

Then, the transmission video signal conversion program extracts a low frequency component from the linear luminance signal by the band limiting means.
Further, the transmission video signal conversion program converts the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means by the up-sampling means to the same number of samples and pixel structure as the linear luminance signal. Upsample to be
The video signal conversion program for transmission uses the low-frequency linear luminance signal extracted by the band-limiting device, the low-frequency linear first color signal and the low-frequency linear second color upsampled by the upsampling device. A low-pass linear third color signal is generated from the signal.

In addition, the transmission video signal conversion program generates a high-frequency luminance signal, which is a high-frequency component of the linear luminance signal, from the linear luminance signal by the high-frequency signal generating means.
Then, the transmission video signal conversion program adds the high frequency luminance signal to the low frequency linear first color signal, the low frequency linear second color signal, and the low frequency linear third color signal by the high frequency signal adding means. Accordingly, the transmission video signal conversion program can generate the first to third color signals which are color signals.

  The video signal transmission system according to claim 5 generates a video signal for transmission from the first to third color signals, which are color signals of three primary colors, and receives the video signal. A video signal transmission system comprising a video signal receiving device that converts the video signal into the color signal, wherein the video signal transmitting device comprises a luminance signal generating means, a band limiting means, and a downsampling means. A non-linear conversion unit, and the video signal receiving apparatus includes a linear conversion unit, a second band limiting unit, an upsampling unit, a color signal generation unit, a high-frequency signal generation unit, and a high-frequency signal. And an adding means.

In such a configuration, the video signal transmission system is configured such that the video signal transmitting device on the video signal transmitting side mixes the color signals of the three primary colors, which are linear signals, at a predetermined mixing ratio by the luminance signal generating means. A linear luminance signal as a signal is generated.
Then, the video signal transmitting apparatus extracts the low frequency component signal from the first color signal and the second color signal by the band limiting unit, and down-samples each extracted signal at a predetermined sampling interval by the down-sampling unit. Sample.

Then, the video signal transmitting apparatus converts the linear luminance signal generated by the luminance signal generation unit by the nonlinear conversion unit to a nonlinear luminance signal by nonlinear conversion, and the low-frequency linear first color signal down-sampled by the down-sampling unit The low-frequency linear second color signal is converted into a low-frequency nonlinear first color signal and a low-frequency nonlinear second color signal, respectively.
The nonlinear luminance signal, the low-frequency nonlinear first color signal, and the low-frequency nonlinear second color signal are transmission video signals.

Then, the video signal receiving device on the video signal receiving side converts the non-linear luminance signal into the linear luminance signal by giving the inverse characteristic of the non-linear conversion on the transmitting side by the linear conversion means, and the low-frequency non-linear first color signal And the low-frequency nonlinear second color signal are converted into a linear low-frequency linear first color signal and a low-frequency linear second color signal, respectively.
Then, the video signal receiving apparatus extracts a low frequency component from the linear luminance signal by the second band limiting unit.

In addition, the video signal receiving apparatus has the same number of samples and pixel structure as the linear luminance signal by converting the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means by the up-sampling means. Upsample to
Then, the video signal receiving device uses the color signal generating means to extract the low frequency linear luminance signal extracted by the second band limiting means, the low frequency linear first color signal and the low frequency linear second signal upsampled by the up sampling means. A low-pass linear third color signal is generated from the color signal.

Further, the video signal receiving apparatus generates a high frequency luminance signal, which is a high frequency component of the linear luminance signal, from the linear luminance signal by the high frequency signal generating means.
Then, the video signal receiving device adds the high-frequency luminance signal to the low-frequency linear first color signal, the low-frequency linear second color signal, and the low-frequency linear third color signal by the high-frequency signal adding means. Accordingly, the video signal receiving apparatus can generate the first to third color signals that are color signals.

The present invention has the following excellent effects.
According to the first to fifth aspects of the present invention, since a luminance signal is generated from a linear color signal, a more accurate luminance signal can be generated, and information for restoring the luminance is transmitted luminance. The signal can be transmitted correctly. Thus, according to the first to fifth aspects of the present invention, it is possible to transmit the luminance satisfying the constant luminance principle, and it is possible to correctly reproduce the luminance information on the receiving side.

According to the first to fifth aspects of the present invention, since the linear color signal is band-limited and down-sampled and then converted into a nonlinear signal, information included in the nonlinear signal is not lost due to the band limitation. Accordingly, the inventions according to claims 1 to 5 can reproduce color information with low distortion.
In addition, according to the first to fifth aspects of the present invention, since the color difference signal is not used, there is no processing for performing nonlinear conversion on the color difference signal, and the SN ratio in the high-definition portion is not increased without increasing the number of bits of the video signal. The decrease can be suppressed.

1 is a system configuration diagram showing a configuration of a video signal transmission system according to a first embodiment of the present invention. It is a block block diagram which shows the structure of the video signal transmitter which concerns on 1st Embodiment of this invention. It is a block block diagram which shows the structure of the video signal receiver which concerns on 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the video signal transmission apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the video signal receiver which concerns on 1st Embodiment of this invention. It is a block block diagram which shows the structure of the transmission signal converter which converts the signal of the YBR format which the video signal transmitter which concerns on 1st Embodiment of this invention transmits into the signal of a YCC format. FIG. 6 is a block diagram showing a configuration of a reception signal conversion apparatus that converts a YCC format signal transmitted by the transmission signal conversion apparatus of FIG. 6 into a YBR format signal that can be received by the video signal reception apparatus according to the first embodiment of the present invention. FIG. It is a system block diagram which shows the structure of the video signal transmission system which concerns on 2nd Embodiment of this invention. It is a block block diagram which shows the structure of the video signal transmission apparatus which concerns on 2nd Embodiment of this invention. It is a block block diagram which shows the structure of the video signal receiver which concerns on 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the video signal transmitter which concerns on 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the video signal receiver which concerns on embodiment of this invention. It is a figure for demonstrating the method (conventional method 1) which transmits the conventional video signal, Comprising: (a) is a block diagram which shows the structure of a transmitter, (b) is a receiver. It is a figure for demonstrating the method (conventional method 2) which transmits the conventional video signal, Comprising: (a) is a block diagram which shows the structure of a transmitter, (b) is a receiver.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment: Configuration of Video Signal Transmission System]
First, the configuration of the video signal transmission system according to the first embodiment of the present invention will be described with reference to FIG.

The video signal transmission system S is a YBR component type transmission system that handles a digital video signal (hereinafter simply referred to as a video signal) with a luminance signal and two color signals.
This video signal transmission system S transmits a video signal via a transmission line N as shown in FIG. Here, the video signal transmission system S includes the video signal transmission device 1 on the side that transmits the video signal, and the video signal reception device 2 on the side that receives the video signal via the transmission path N.

The video signal transmission device 1 generates and transmits a video signal for transmission from an R (red) signal, a G (green) signal, and a B (blue) signal that are color signals of three primary colors.
The video signal transmitting apparatus 1 uses a RGB signal input from the camera C to obtain a luminance signal (Y ^α ) subjected to nonlinear compression / decompression and low frequency components (B _LD ^α , R _LD ^α ) of two color signals. It is generated and transmitted to the video signal receiving apparatus 2 via a transmission line N such as a cable or a communication line. Here, the video signal transmitting apparatus 1 inputs RGB signals from the camera C, but may be configured to input video signals from an apparatus that electronically generates video signals, such as a CG apparatus.

The video signal receiving device 2 receives a luminance signal and low frequency components of two color signals, generates an RGB signal from the signals, and outputs the RGB signal.
This video signal receiver 2 receives the luminance signal (Y ^α ) and the low frequency components (B _LD ^α , R _LD ^α ) of the two color signals from the video signal transmitter 1 via the transmission path N. And output to the display device D as RGB signals. The display device D may be configured to be provided inside the video signal receiving device 2.

Further, the RGB signals output from the video signal receiving device 2 may be transmitted again by the video signal transmission system after being processed by various video signal processing devices.
Hereinafter, the configurations of the video signal transmitting apparatus 1 and the video signal receiving apparatus 2 according to the first embodiment of the present invention will be described.

[Configuration of video signal transmitter]
First, the configuration of the video signal transmitting apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG. 2 (refer to FIG. 1 as appropriate). Here, the video signal transmission device 1 includes a luminance signal generation unit 10, a band limiting unit 11, a down-sampling unit 12, and a non-linear conversion unit 13. The video signal transmission device 1 also includes input means for inputting RGB signals, and output means for outputting the luminance signal and the low frequency components of the color signals to the video signal reception device 2 via the transmission line N. However, illustration is omitted here. Also, illustration of the delay means (delay circuit) for correcting the processing delay of each means is omitted here.

  The RGB signal input to the video signal transmitting apparatus 1 is a linear signal having a linear relationship between the signal level and the light intensity. In the case where the RGB signal is a non-linear signal subjected to gamma correction, the input RGB signal is further provided with linear conversion means (not shown) for converting it into a linear signal by inverse gamma characteristics.

  The luminance signal generation means 10 generates a luminance signal by mixing RGB signals, which are linear signals input via an input means (not shown), at a predetermined mixing ratio. The luminance signal generation means 10 generates a luminance signal (linear luminance signal) Y, which is a linear luminance signal, by a mixing equation shown in the following equation (2).

Here, r, g, and b are coefficients for generating a luminance signal. This coefficient may be based on a general standard for generating a luminance signal from an RGB signal. For example, in the case of an HDTV signal standard, r = 0.2126, g = 0.7152, and b = 0.0722. . Alternatively, although the luminance is not strictly expressed, these may be simplified so that r = 0.2, g = 0.7, b = 0.1, and the like.
The luminance signal generation unit 10 outputs the generated luminance signal Y to the non-linear conversion unit 13.

The band limiting unit 11 extracts a signal (B _L , R _L ) having a predetermined low frequency component from the B signal and the R signal input via the input unit (not shown). The band limiting unit 11 can be configured by a general low-pass filter.

  This low frequency component is determined in advance according to the degree of down sampling in the down sampling means 12 to be described later. For example, if the down sampling is halved, the low frequency component of the frequency component Half of the ingredients.

That is, for example, when the transmission format of the video signal is 4: 2: 2, the band limiting unit 11 can be configured by a horizontal one-dimensional filter, and among the horizontal frequency components, the low frequency side It is assumed that only a half band signal is passed. For example, when the transmission format of the video signal is 4: 2: 0 format, the band limiting unit 11 can be configured by a horizontal and vertical two-dimensional filter, and each of frequency components in the horizontal direction and the vertical direction. It is assumed that only the signal of the half band on the low frequency side is allowed to pass.
The band limiting unit 11 outputs the extracted signals (B _L , R _L ) to the downsampling unit 12.

The down-sampling unit 12 down-samples each signal (B _L , R _L ) extracted by the band limiting unit 11 at a predetermined sampling interval (down-sampling ratio).
This sampling interval is a predetermined interval according to the transmission format of the video signal. For example, when the video signal transmission format is 4: 2: 2, the down-sampling means 12 down-samples every other pixel in the horizontal direction. For example, when the video signal transmission format is 4: 2: 0, the down-sampling unit 12 down-samples the pixels every other pixel in both the horizontal direction and the vertical direction.

By changing the filter characteristics in the band limiting unit 11 and the downsampling ratio in the downsampling unit 12, a format other than the 4: 2: 2 format or 4: 2: 0 format, for example, the 3: 1: 1 format. It is possible to obtain a desired sample number ratio.
The downsampling unit 12 outputs the downsampled signals (B _LD , R _LD ) to the nonlinear conversion unit 13.

The non-linear conversion unit 13 converts each signal (B _LD , R _LD ) that is a linear signal down-sampled by the down-sampling unit 12 and the luminance signal Y that is a linear signal generated by the luminance signal generation unit 10 into a non-linear signal. To convert.
This non-linear transformation is a process (non-linear compression / decompression process) for expanding a signal in a region with a low signal level and compressing a signal in a region with a high signal level. In general, the nonlinear transformation can be expressed by the following equations (3) and (4).

Here, E is a linear signal before nonlinear transformation, E ′ is a nonlinear signal after nonlinear transformation, and α, a, b, c, and d are coefficients. It should be noted that a region where E is small may be given a linear characteristic with respect to E ′ = eE (e is a coefficient).
For example, in the HDTV signal standard, the conversion equation from the linear signal E to the nonlinear signal E ′ is defined as shown in the following equation (5).

The non-linear conversion means 13 may perform non-linear conversion using the equation (5).
Here, the above equation (3) is simplified so that a = 1, b = 0, and c = 0, so that E ^α (notation of power of α) is nonlinear after nonlinear transformation in the nonlinear transformation means 13. Signal notation.

That is, the nonlinear conversion means 13 converts the signal B _LD down-sampled by the down-sampling means 12 into a low-frequency nonlinear blue signal B _LD ^α, and converts the signal R _LD into a low-frequency nonlinear red signal R _LD ^α . Further, the non-linear conversion means 13 converts the luminance signal Y, which is a linear signal generated by the luminance signal generation means 10, into a non-linear luminance signal Y ^α by non-linear conversion.

The non-linear luminance signal Y ^α , the low-frequency non-linear blue signal B _LD ^α and the low-frequency non-linear red signal R _LD ^α converted by the non-linear conversion means 13 are video signals for transmission output to the outside.
In this way, the non-linear luminance signal Y ^α , the low-frequency non-linear blue signal B _LD ^α and the low-frequency non-linear red signal R _LD ^α converted by the non-linear conversion means 13 are output to the video signal receiving device 2 via the output means not shown. Sent to.

  The configuration of the video signal transmission device 1 according to the first embodiment of the present invention has been described above, but the present invention is not limited to the format of the present embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the video signal transmitting apparatus 1 is realized by software, a general computer equipped with a CPU and a memory (not shown) can be operated by a transmission video signal generation program that functions as the above-described units.

[Configuration of video signal receiver]
Next, the configuration of the video signal receiving apparatus 2 according to the first embodiment of the present invention will be described with reference to FIG. Here, the video signal receiving device 2 includes a linear conversion unit 20, a band limiting unit 21, a high frequency signal generating unit 22, an upsampling unit 23, a color signal generating unit 24, and a high frequency signal adding unit 25. It is equipped with. Note that the video signal receiving apparatus 2 receives an input means for inputting the luminance signal (Y ^α ) and the low frequency components (B _LD ^α , R _LD ^α ) of the color signal via the transmission line N, and RGB signals. Although an output means for outputting is also provided, the illustration is omitted here. Also, illustration of the delay means (delay circuit) for correcting the processing delay of each means is omitted here.

The linear conversion means 20 is transmitted from the video signal transmission apparatus 1 and inputted through the input means (not shown), and the luminance signal (nonlinear luminance signal Y ^α ) and the low frequency component of the color signal (low frequency nonlinear blue signal B). _LD ^α , low-frequency non-linear red signal R _LD ^α ) is given the inverse characteristic of non-linear transformation performed in the video signal transmitting apparatus 1, so that a linear luminance signal (Y) and a linear low-frequency component color signal (Low band linear blue signal B _LD , low band linear red signal R _LD ). The nonlinear luminance signal ^Yα is generated from the RGB signal which is a linear signal by the video signal transmitting apparatus 1 according to the equation (2) and then nonlinearly converted. By performing conversion based on the inverse characteristic of the nonlinear conversion, the (linear) luminance signal Y is correctly reproduced.
The linear converting means 20 outputs the converted linear luminance signal Y to the band limiting means 21 and the high frequency signal generating means 22. The linear conversion means 20 outputs the converted low-frequency linear blue signal B _LD and low-frequency linear red signal R _LD to the up-sampling means 23.

The band limiting unit 21 extracts a predetermined low frequency component (Y _L ) from the linear luminance signal Y converted by the linear conversion unit 20. The band limiting unit 21 extracts the same low frequency component as the band limiting unit 11 (see FIG. 2) of the video signal transmitting apparatus 1. The band limiting unit 21 outputs the extracted signal (low band linear luminance signal Y _L ) to the high band signal generating unit 22 and the color signal generating unit 24.

The high frequency signal generating means 22 extracts a high frequency component signal (high frequency luminance signal Y _H ) from the linear luminance signal Y converted by the linear conversion means 20. Here, the high frequency signal generating means 22 subtracts the low frequency linear luminance signal Y _L band-limited by the band limiting means 21 from the linear luminance signal Y, so that a high frequency signal component of the linear luminance signal Y is high. generating a frequency luminance signal _{Y H.}

The high frequency signal generating means 22 may be configured to extract a predetermined high frequency component from the linear luminance signal Y. In this case, the high-frequency signal generation means 22 can be configured by a general high-pass filter. The high frequency component is determined in advance as the remaining high frequency component of the low frequency component performed in the band limiting unit 21. When the high-frequency signal generating unit 22 is configured with a high-pass filter, the high-frequency signal generating unit 22 does not use the low-frequency linear luminance signal Y _L band-limited by the band limiting unit 21.
The high frequency signal generating means 22 outputs the generated high frequency luminance signal Y _H to the high frequency signal adding means 25.

The up-sampling means 23 converts the low-frequency linear blue signal B _LD and the low-frequency linear red signal R _LD that are the linear signals converted by the linear conversion means 20 into the same number of samples and pixel structure as the (linear) luminance signal Y. It is intended to upsample.

  For example, when the transmission format of the video signal transmitted from the video signal transmission device 1 is 4: 2: 2, the up-sampling unit 23 inserts a pixel for each pixel in the horizontal direction. When the transmission format of the video signal transmitted from the video signal transmission device 1 is 4: 2: 0 format, the up-sampling unit 23 inserts a pixel for each pixel in both the horizontal direction and the vertical direction. Here, the pixel is inserted by inserting a pixel having a pixel value obtained from an interpolation filter from adjacent pixels.

The up-sampling unit 23 outputs the up-sampled low-frequency linear blue signal B _L and low-frequency linear red signal R _L to the color signal generating unit 24 and the high-frequency signal adding unit 25.

The chrominance signal generation unit 24 generates a low-frequency signal from the low-frequency linear luminance signal Y _L band-limited by the band-limiting device 21, the low-frequency linear blue signal B _L and the low-frequency linear red signal R _L up-sampled by the up-sampling device 23. It generates a gamut green signal _GL . The color signal generation unit 24 generates a low-frequency linear green signal _{GL according} to the following equation (6).

Here, r, g, and b are the same as the coefficients used in the equation (2) in the luminance signal generating means 10 (see FIG. 2) of the video signal transmitting apparatus 1.
The color signal generation unit 24 outputs the generated low frequency linear green signal _GL to the high frequency signal addition unit 25.

High band signal adding means 25, and the low frequency linear blue signal B _L and a low linear red R _L which is upsampled in upsampling unit 23, into a low-frequency linear green signal G _L generated by the color signal generator 24, by adding the high-frequency luminance signal Y _H generated by each high frequency signal generator 22, and generates an RGB signal. That is, the high frequency signal adding means 25 generates an RGB signal by the following equation (7).

As described above, the high-frequency signal adding means 25 includes the low-frequency component signal (R _L , G _L , B _L ) of the RGB signal band-limited and the high-frequency component signal (Y _H ) of the luminance signal. From this, an RGB signal can be generated.

  The configuration of the video signal receiving apparatus 2 according to the first embodiment of the present invention has been described above, but the present invention is not limited to the format of the present embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the video signal receiving apparatus 2 is realized by software, a general computer equipped with a CPU and a memory (not shown) can be operated by the transmission video signal conversion program that functions as the above-described units.

[First Embodiment: Operation of Video Signal Transmission System]
Next, the operation of the video signal transmission system S according to the first embodiment of the present invention will be described. In the following, the operation of the video signal transmitting apparatus 1 and the operation of the video signal receiving apparatus 2 will be described sequentially.

[Operation of video signal transmitter]
First, the operation of the video signal transmitting apparatus 1 will be described with reference to FIG. 4 (refer to FIGS. 1 and 2 as appropriate).

First, the video signal transmitting apparatus 1 inputs a video signal from the outside by an input unit (not shown) (step S1). This video signal is a three-primary color signal (RGB signal) which is a linear signal.
Then, the video signal transmission apparatus 1 generates the luminance signal Y by mixing the RGB signals input in step S1 at a predetermined mixing ratio by the luminance signal generation means 10 (step S2). Specifically, the luminance signal generation unit 10 generates the luminance signal Y by the above equation (2).

Then, the video signal transmitting apparatus 1 extracts a predetermined low frequency component (B _L , R _L ) from the B signal and the R signal input in step S1 by the band limiting unit 11 (step S3).
Further, the video signal transmitting apparatus 1 uses the down-sampling means 12 to convert each signal (B _L , R _L ) extracted in step S3 according to the transmission format (4: 2: 2 format, 4: 2: 0 format, etc.). A signal (B _LD , R _LD ) downsampled at a predetermined sampling interval (downsample ratio) is generated (step S4).

Then, the video signal transmitting apparatus 1 uses the nonlinear conversion means 13 to nonlinearly convert the low frequency component signal (B _LD , R _LD ) generated in step S4 and the luminance signal Y generated in step S2 by nonlinear conversion. It converts into a signal (step S5). That is, the non-linear conversion means 13 converts the luminance signal Y into a non-linear luminance signal Y ^α , converts the low frequency linear blue signal B _LD into a low frequency non-linear blue signal B _LD ^α, and converts the low frequency linear red signal R _LD into a low frequency non-linearity. Convert to red signal R _LD ^α .

Thereafter, the video signal transmitting apparatus 1 transmits the non-linear luminance signal Y ^α , the low-frequency non-linear blue signal B _LD ^α, and the low-frequency non-linear red signal R _LD ^α converted in step S5 by the output unit (not shown). As a video signal for use, the video signal is output to the video signal receiver 2 via the transmission line N (step S6).
Through the above operation, the video signal transmitting apparatus 1 converts the luminance signal (non-linear luminance signal Y ^α ) and the color signal (low-frequency nonlinear blue signal B _LD ^α , low-frequency nonlinear red signal R _LD ^α ) into the video signal receiving device. 2 can be transmitted.

[Operation of video signal receiver]
Next, the operation of the video signal receiving device 2 will be described with reference to FIG.

First, the video signal receiving device 2 transmits a luminance signal (nonlinear luminance signal Y ^α ) and a color signal, which are video signals for transmission, from the video signal transmitting device 1 via the transmission path N by an input unit (not shown). (Low-frequency nonlinear blue signal B _LD ^α , Low-frequency nonlinear red signal R _LD ^α ) is input (step S10).
Then, the video signal receiving apparatus 2 gives the inverse characteristic of the nonlinear conversion to the nonlinear luminance signal Y ^α , the low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear red signal R _LD ^α input in step S10 by the linear conversion means 20. Thus, each signal is converted into a linear luminance signal Y, a low-frequency linear blue signal B _LD , and a low-frequency linear red signal R _LD (step S11).

Then, the video signal receiving apparatus 2 extracts the low frequency component (Y _L ) from the linear luminance signal Y converted in step S11 by the band limiting unit 21 (step S12).

The video signal receiving device 2, the high frequency signal generating unit 22, a linear luminance signal Y converted in step S11, by subtracting the low frequency linear luminance signal Y _L extracted in step S12, the luminance signal high generating a high-frequency luminance signal _{Y H,} which is the frequency component (step S13).

Further, the video signal receiving apparatus 2 uses the up-sampling means 23 to convert the low-frequency linear blue signal B _LD and the low-frequency linear red signal R _LD converted in step S11 into the same number of samples and pixel structure as the (linear) luminance signal Y. Up-sampling is performed as follows (step S14).

The video signal receiving device 2, by the color signal generator 24, low-frequency linear luminance signal band-limited in Step S12 Y _L and the low frequency linear blue signal B _L and low linear red R which upsample in step S14 _A low-pass linear green signal _GL is generated from _L (step S15). Specifically, the color signal generation unit 24 generates the low-pass linear green signal _{GL according} to the equation (6).

The video signal receiving device 2, the high frequency signal adding means 25, and the low frequency linear blue signal B _L and a low linear red R _L which is upsampled at step S14, the low-frequency linear green signal G generated in step S15 in the _L, by adding the high-frequency luminance signal _{Y H} generated at the step S13, and generates an RGB signal (step S16).

Thereafter, the video signal receiving apparatus 2 outputs the RGB signal (video signal) generated in step S16 by output means (not shown) (step S17).
Through the above-described operation, the video signal receiving device 2 has the luminance signal (non-linear luminance signal Y ^α ) and color signal (low-frequency non-linear blue signal B _LD ^α , low-frequency non-linear red signal R _LD ^α ) output from the video signal transmitting device 1. ), A video signal of three primary color signals (RGB signals) can be generated.

[Comparison of color reproduction errors]
Next, the performance of the video signal transmission method by the video signal transmission system S (video signal transmission device 1 and video signal reception device 2) according to the first embodiment of the present invention and the video signal transmission method by the conventional method will be described. The comparison will be described.
Here, all combinations of 8-bit nonlinear R, G, and B signals using an index ΔE _ab ^* that indicates a color error in the L ^* a ^* b ^* uniform color space, which is a general color reproduction evaluation method. The reproduced color error ΔE _ab ^* was collected. The conventional method is the conventional method 2 shown in FIG.

As shown in this table, the average value and the maximum value of the color error ΔE _ab ^* are small in the method of the present invention, and the method of the present invention greatly improves the color reproduction error compared to the conventional method. I understand that
As described above, the present invention can suppress a decrease in the SN ratio while enabling constant luminance transmission.

  The configuration and operation of the video signal transmission system according to the first embodiment have been described above. In the first embodiment, the transmission system is a YBR component system that handles a luminance signal and two color signals. However, in a digital compression encoding device that compresses and encodes a video signal, the luminance signal and the color difference signal are used. Some video signals are compressed and encoded.

  Therefore, here, a transmission signal conversion device that converts a video signal transmitted by the video signal transmission device 1 of the video signal transmission system according to the first embodiment into a YCC format video signal composed of a luminance signal and two color difference signals; A reception signal conversion device that converts a YCC format video signal converted by the transmission signal conversion device into a YBR format video signal that is received by the video signal reception device 2 will be described.

[Configuration of transmission signal converter]
First, the configuration of the transmission signal conversion device 3 will be described with reference to FIG. Here, the transmission signal conversion device 3 includes a linear conversion unit 30, a band limiting unit 31, a downsampling unit 32, a non-linear conversion unit 33, and a color difference signal generation unit 34. The transmission signal conversion device 3 includes input means for inputting the luminance signal and color signal generated in the video signal transmission device 1 and output means for outputting the luminance signal and the color difference signal to the outside. Omitted. Also, illustration of the delay means (delay circuit) for correcting the processing delay of each means is omitted here.

The linear conversion unit 30 gives a luminance signal (non-linear luminance signal Y ^α ) input via an input unit (not shown) to the inverse characteristic of the non-linear conversion performed in the video signal transmission device 1, thereby obtaining a linear luminance signal ( The signal is converted into a linear luminance signal Y).
The linear conversion unit 30 outputs the converted linear luminance signal Y to the band limiting unit 31.

The band limiting unit 31 extracts a predetermined low frequency component (Y _L ) from the linear luminance signal Y converted by the linear conversion unit 30. The band limiting unit 31 extracts the same low frequency component as the band limiting unit 11 (see FIG. 2) of the video signal transmitting apparatus 1. The band limiting unit 31 outputs the extracted signal (low band linear luminance signal Y _L ) to the downsampling unit 32.

Down-sampling means 32 is for down-sampled low frequency linear luminance signal Y _L predetermined sampling interval extracted by the band limiting means 31 (downsampling ratio). The downsampling unit 32 performs downsampling at the same sampling interval (downsampling ratio) as the downsampling unit 12 (see FIG. 2) of the video signal transmitting apparatus 1.
The downsampling unit 32 outputs the downsampled low frequency linear luminance signal Y _LD to the non-linear conversion unit 33.

The nonlinear conversion means 33 converts the low-frequency linear luminance signal Y _LD that is the linear signal down-sampled by the down-sampling means 32 into a nonlinear signal (low-frequency nonlinear luminance signal Y _LD ^α ). The nonlinear conversion means 33 performs the same conversion as the nonlinear conversion performed in the nonlinear conversion means 13 (see FIG. 2) of the video signal transmission apparatus 1.
The nonlinear conversion means 33 outputs the converted low-frequency nonlinear luminance signal Y _LD ^α to the color difference signal generation means 34.

The chrominance signal generation means 34 is a low-frequency nonlinear luminance signal Y _LD ^α converted by the nonlinear conversion means 33, a low-frequency nonlinear blue signal B _LD ^α and a low-frequency nonlinear red signal R _LD input via an input means (not shown). Two color difference signals are generated from ^α by mixing these signals at a predetermined mixing ratio. The two color difference signals are often expressed by a difference signal between a blue signal and a luminance signal and a difference signal between a red signal and a luminance signal. In this case, the color difference signal generation means 34 is represented by the following equation (8). The difference signal between the low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear luminance signal Y _LD ^α is the color difference signal Cb _LD ^α , and the difference between the low-frequency nonlinear red signal R _LD ^α and the low-frequency nonlinear luminance signal Y _LD ^α. The signal is a color difference signal Cr _LD ^α .

Note that the color difference signal generation unit 34 may divide by a predetermined coefficient so that the dynamic range of the color difference signal is the same as the dynamic range of the luminance signal.
That is, the color difference signal generation means 34 divides the difference signal between the low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear luminance signal Y _LD ^α by the coefficient kcb as shown in the following equation (9). and cb _LD ^alpha, and the color difference signals _{Cr LD} ^alpha by dividing the difference signal and the low frequency non-linear red signal _{R LD} ^alpha and low nonlinear luminance signal _{Y LD} ^alpha by a factor kcr. The coefficients kcb and kcr are coefficients for making the dynamic range of the color difference signal the same as the dynamic range of the luminance signal. However, the values may be simplified to be “2”.

The color difference signals Cb _LD ^α and Cr _LD ^α generated by the color difference signal generation unit 34 are output to the outside through an output unit (not shown). Incidentally, the luminance signal output means (not shown) directly outputs a nonlinear luminance signal Y ^alpha input via the input means (not shown).
Thus, the transmission signal conversion device 3 can convert the video signal generated in the video signal transmission device 1 into a YCC format video signal of a luminance signal and two color difference signals.

  The configuration of the transmission signal conversion device 3 according to the embodiment of the present invention has been described above, but the present invention is not limited to the format of the present embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the transmission signal conversion device 3 is realized by software, a general computer having a CPU and a memory (not shown) can be operated by the transmission signal conversion program that functions as the above-described units.

Here, the transmission signal conversion device 3 is configured as a device separate from the video signal transmission device 1 as a device that converts the video signal output from the video signal transmission device 1 (see FIG. 2). The transmission signal conversion device 3 may be configured by being incorporated in the video signal transmission device 1.
In this case, the transmission signal conversion device 3 may be disposed after the nonlinear conversion means 13 of the video signal transmission device 1. The linear conversion means 30 receives the non-linear luminance signal Y ^α from the non-linear conversion means 13, and the color difference signal generation means 34 receives the low-frequency non-linear blue signal B _LD ^α and the low-frequency non-linear red signal R _LD ^α from the non-linear conversion means 13. Enter.
As a result, the video signal transmission device 1 can be configured as a device that transmits a video signal in the YCC format.

[Configuration of received signal converter]
Next, the configuration of the received signal converter 4 will be described with reference to FIG. Here, the received signal conversion apparatus 4 includes a linear conversion unit 30, a band limiting unit 31, a down-sampling unit 32, a non-linear conversion unit 33, and a color signal generation unit 40.
Since the configuration other than the color signal generation unit 40 is the same as that of the transmission signal conversion device 3 described with reference to FIG. 6, the same reference numerals are given and description thereof is omitted.

The color signal generation means 40 is a color signal obtained from the low-frequency nonlinear luminance signal Y _LD ^α converted by the nonlinear conversion means 33 and the color difference signals Cb _LD ^α and Cr _LD ^α input via the input means (not shown). A low-frequency nonlinear blue signal B _LD ^α and a low-frequency nonlinear red signal R _LD ^α are generated. The generation of the color signal corresponds to the inverse conversion of the color difference signal generation.

When the color difference signal generation unit 34 (see FIG. 6) calculates the color difference signals Cb _LD ^α and Cr _LD ^{α according} to the above equation (8), the color signal generation unit 40 is reduced by the following equation (10). A non-linear blue signal B _LD ^α and a low-frequency non-linear red signal R _LD ^α are generated.

Further, when the color signal generation unit 40 calculates the color difference signals Cb _LD ^α and Cr _LD ^{α according} to the equation (9) in the color difference signal generation unit 34 (see FIG. 6), the following equation (11) A low-frequency nonlinear blue signal B _LD ^α and a low-frequency nonlinear red signal R _LD ^α are generated.

It should be noted that the color difference signal generation means 34 (see FIG. 6) generates a color difference signal at what mixing ratio, for example, whether the color difference signals Cb _LD ^α and Cr _LD ^α are generated by the equation (8), Whether the color difference signals Cb _LD ^α and Cr _LD ^α are generated by the equation (9) is assumed to be known in the reception signal conversion device 4.
The low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear red signal R _LD ^α generated by the color signal generating means 40 are output to the outside through output means (not shown). Incidentally, the luminance signal output means (not shown) directly outputs a nonlinear luminance signal Y ^alpha input via the input means (not shown).

  In this manner, the reception signal conversion device 4 converts the YCC format video signal of the luminance signal and the two color difference signals generated by the transmission signal conversion device 3 into the YBR format video signal of the luminance signal and the two color signals. Can be converted to This video signal can be used as an input signal to the video signal receiving device 2 (see FIG. 3).

  The configuration of the received signal conversion apparatus 4 according to the embodiment of the present invention has been described above, but the present invention is not limited to the format of the present embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the reception signal conversion device 4 is realized by software, a general computer having a CPU and a memory (not shown) can be operated by the reception signal conversion program that functions as the above-described units.

In addition, here, the reception signal conversion device 4 is configured to output the converted video signal to the video signal reception device 2 (see FIG. 3), and is configured as a separate device from the video signal reception device 2, The reception signal conversion device 4 may be configured to be incorporated in the video signal reception device 2.
In this case, the reception signal conversion device 4 may be arranged in the preceding stage of the linear conversion means 20 of the video signal reception device 2. Then, the input means (not shown) outputs the input nonlinear luminance signal Y ^α to the linear conversion means 20, and the color signal generation means 40 outputs the low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear red signal R _LD ^α . Output to the linear conversion means 20.
Accordingly, the video signal receiving device 2 can be configured as a device that receives a YCC format video signal.

[Second Embodiment: Configuration of Video Signal Transmission System]
Next, the configuration of the video signal transmission system according to the second embodiment of the present invention will be described with reference to FIG.

Video signal transmission system S _B as a digital video signal (video signal), the color signals of RGB to the low frequency components has been band-limited, adding high frequency components of the luminance signal into one of the color signals Transmission system.
The video signal transmission system S _B, as shown in FIG. 8, for transmitting a video signal through the transmission path N. Here, the video signal transmission system S _B is provided with a video signal transmission apparatus 1B on the side of transmitting the video signal includes a video signal receiving apparatus 2B on the side that receives the video signal via the transmission path N.

The video signal transmitting apparatus 1B generates and transmits a video signal for transmission from an R (red) signal, a G (green) signal, and a B (blue) signal, which are three primary color signals.
This video signal transmission device 1B adds a high frequency component of a luminance signal to any one of the low frequency components (here, a G signal component) of each color signal of the RGB signal input from the camera C, The data is transmitted to the video signal receiving device 2 via a transmission line N such as a communication line. Here, the video signal transmission apparatus 1B receives RGB signals from the camera C, but, like the video signal transmission system S (see FIG. 1), an apparatus that electronically generates a video signal such as a CG apparatus. It may be configured to input from.

The video signal receiving device 2B receives a signal in which a high frequency component of a luminance signal is added to one of the low frequency components of each color signal of an RGB signal, and generates and outputs an RGB signal from the signal. .
This video signal receiving device 2B receives a signal in which the high frequency component of the luminance signal is added to one of the low frequency components of the color signal from the video signal transmitting device 1B via the transmission line N, and RGB It outputs to the display apparatus D as a signal. The display device D may be configured to be provided inside the video signal receiving device 2B.

Further, in the video signal transmission system S _B, it is assumed that the addition of high-frequency component of the luminance signal to the low frequency components of the G signal, the high-frequency component of the luminance signal is added to which color signals It is good as well.
The configurations of the video signal transmission device 1B and the video signal reception device 2B according to the second embodiment of the present invention will be described below.

[Configuration of video signal transmitter]
First, referring to FIG. 9 (refer to FIG. 2 and FIG. 8 as appropriate), the configuration of the video signal transmitting apparatus 1B according to the second embodiment of the present invention will be described. Here, the video signal transmitting apparatus 1B includes a luminance signal generating unit 10, a band limiting unit 11B, a downsampling unit 12, a non-linear conversion unit 13B, a high frequency signal generating unit 14, and a high frequency signal adding unit 15. It is equipped with.
The configurations other than the band limiting unit 11B, the non-linear conversion unit 13B, the high frequency signal generating unit 14, and the high frequency signal adding unit 15 are the same as those of the video signal transmitting apparatus 1 described in FIG. The description is abbreviate | omitted and attached | subjected.

The video signal transmitting apparatus 1B outputs RGB signals to the video signal receiving apparatus 2B via the transmission line N, and the high frequency component of the luminance signal and the low frequency component of the color signal are output. Output means is also provided, but the illustration is omitted here. Also, illustration of the delay means (delay circuit) for correcting the processing delay of each means is omitted here.
In addition, the RGB signal input to the video signal transmission device 1B is a linear signal as in the video signal transmission device 1.

The band limiting unit 11B extracts predetermined low frequency component signals (G _L , B _L , R _L ) from the G signal, B signal, and R signal input via the input unit (not shown). To do. Note that the processing content of the band limiting in the band limiting unit 11B is the same as that of the band limiting unit 11 described with reference to FIG.
The band limiting unit 11B outputs the extracted signal (low-frequency linear green signal G _L ) to the high-frequency signal adding unit 15, and extracts the extracted signals (low-frequency linear blue signal B _L , low-frequency linear red signal R _L ). Output to the down-sampling means 12.

The high frequency signal generation unit 14 extracts a high frequency component signal (high frequency luminance signal Y _H ) from the linear luminance signal Y generated by the luminance signal generation unit 10. Here, the high-frequency signal generating unit 14 includes a band limiting unit 141 and a subtracting unit 142.

The band limiting unit 141 extracts a signal (Y _L ) of a predetermined low frequency component from the luminance signal Y generated by the luminance signal generating unit 10. Note that the processing content of the band limiting in the band limiting unit 141 is the same as that of the band limiting unit 11 described with reference to FIG. The band limiting unit 141 outputs the extracted signal (low band linear luminance signal Y _L ) to the subtracting unit 142.

The subtracting unit 142 subtracts the low frequency linear luminance signal Y _L band-limited by the band limiting unit 142 from the luminance signal Y generated by the luminance signal generating unit 10 to thereby obtain a high frequency that is a high frequency component of the luminance signal. and it generates a luminance signal Y _H. The subtracting unit 142 outputs the generated high frequency luminance signal Y _H to the high frequency signal adding unit 15.

Note that the high frequency signal generation means 14 may be configured to extract a predetermined high frequency component from the linear luminance signal Y. In this case, the high-frequency signal generation means 14 can be configured by a general high-pass filter. This high frequency component is determined in advance as the remaining high frequency component of the low frequency component performed in the band limiting unit 11B. In the case of constituting a high-frequency signal generating means 14 by the high-pass filter, band limiting device 11B does not need to generate a low-frequency linear luminance signal Y _L.
The high frequency signal generation unit 14 outputs the generated high frequency luminance signal Y _H to the high frequency signal addition unit 15.

High frequency signal adding means 15 is for adding the high-band luminance signal Y _H generated by the high frequency signal generator 14, the low-frequency linear green signal G _L that is band-limited by band limiting device 11B. In the linear signal (luminance-added green signal) generated by the high-frequency signal adding means 15, the high-frequency component is the high-frequency component of the luminance signal Y, and the low-frequency component is the low-frequency component of the G signal. It becomes a frequency component.
The high-frequency signal adding unit 15 outputs the generated luminance addition green signal (G _L + Y _H ) to the non-linear conversion unit 13B.

The non-linear conversion means 13B is a signal (B _LD , R _LD ) that is a linear signal down-sampled by the down-sampling means 12 and a luminance addition green signal (G _L + Y) that is a linear signal generated by the high-frequency signal addition means 15. _H ) is converted into a nonlinear signal.
That is, the nonlinear conversion means 13B converts the signal B _LD down-sampled by the down-sampling means 12 into a low-frequency nonlinear blue signal B _LD ^α, and converts the signal R _LD into a low-frequency nonlinear red signal R _LD ^α . Further, the non-linear conversion unit 13B converts the luminance addition green signal (G _L + Y _H ) generated by the high frequency signal addition unit 15 into a non-linear luminance addition green signal (G _L + Y _H ) ^α by performing non-linear conversion. The processing content of the nonlinear conversion in the nonlinear conversion means 13B is the same as that of the nonlinear conversion means 13 described with reference to FIG.
The non-linear luminance addition green signal ( _GL + Y _H ) ^α , the low-frequency non-linear blue signal B _LD ^α, and the low-frequency non-linear red signal R _LD ^α converted by the non-linear conversion means 13B become a transmission video signal output to the outside. .
Thus, non-linear luminance addition green signal converted by the nonlinear conversion unit _{13B (G L + Y H)} α, the low-frequency nonlinear blue signal _{B LD} ^alpha and low nonlinear red _{R LD} ^alpha, via an output means which is not shown And transmitted to the video signal receiving device 2B.

  The configuration of the video signal transmission device 1B according to the second embodiment of the present invention has been described above, but the present invention is not limited to the format of this embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the video signal transmitting apparatus 1B is realized by software, a general computer equipped with a CPU and a memory (not shown) can be operated by a transmission video signal generation program that functions as the above-described units.

[Configuration of video signal receiver]
Next, the configuration of the video signal receiving device 2B according to the second embodiment of the present invention will be described with reference to FIG. 10 (refer to FIGS. 3 and 9 as appropriate). Here, the video signal receiving device 2B includes linear conversion means 20B, high-frequency signal generation means 22B, up-sampling means 23, and high-frequency signal addition means 25B.
The components other than the linear conversion unit 20B, the high-frequency signal generating unit 22B, and the high-frequency signal adding unit 25B are the same as those of the video signal receiving device 2 described with reference to FIG. The description is omitted.

The video signal receiving apparatus 2B, via the transmission path N, the non-linear luminance addition green signal ^{_{(G L + Y H) α}} , low frequency non-linear blue signal _{B LD} ^alpha and the low nonlinear red input means for inputting _{R LD} ^alpha In addition, although an output means for outputting RGB signals is also provided, the illustration is omitted here. Also, illustration of the delay means (delay circuit) for correcting the processing delay of each means is omitted here.

Linear transformation means 20B is transmitted from the video signal transmission apparatus 1B, the non-linear luminance addition green signal input via the input means (not _{shown) (G L + Y H)} α, low frequency non-linear blue signal B _LD ^alpha and low nonlinear the red signal R _LD ^alpha, by providing an inverse characteristic of the nonlinear conversion performed in the video signal transmission apparatus 1B, linear signal (linear luminance addition green signal (G L _{+ Y H),} the low-pass linear blue signal B _LD and a low linear Red signal R _LD ).
The linear conversion means 20B outputs the converted linear luminance addition green signal (G _L + Y _H ) to the output means (not shown) as a G signal and also outputs it to the high frequency signal generation means 22B. The linear conversion means 20B outputs the converted low-frequency linear blue signal B _LD and low-frequency linear red signal R _LD to the up-sampling means 23.

The high-frequency signal generation unit 22B extracts a high-frequency component signal (high-frequency luminance signal Y _H ) from the linear luminance addition green signal (G _L + Y _H ) converted by the linear conversion unit 20B. Here, the high frequency signal generating means 22B includes a band limiting means 221 and a subtracting means 222.
The band limiting unit 221 extracts a predetermined low frequency component (G _L ) from the linear luminance addition green signal (G _L + Y _H ) converted by the linear conversion unit 20B. Note that the band limiting unit 221 extracts the same low frequency component as the band limiting unit 11B (see FIG. 9) of the video signal transmitting apparatus 1B. The band limiting unit 221 outputs the extracted signal (low band linear green signal G _L ) to the subtracting unit 222.
The subtracting means 222 subtracts the low-frequency linear green signal _GL band-limited by the band-limiting means 221 from the linear luminance-added green signal (G _L + Y _H ) converted by the linear converting means 20B, thereby increasing the luminance signal high. to thereby generate a high-frequency luminance signal Y _H, which is the frequency component. The subtraction unit 222 outputs the generated high-frequency luminance signal Y _H in the high band signal addition means 25B.

Incidentally, the high-frequency signal generating means 22B from the linear luminance addition green signal (G L _{+ Y H),} it may be constructed as to extract a high frequency component determined in advance. In this case, the high-frequency signal generating means 22B can be configured by a general high-pass filter. This high frequency component is determined in advance as the remaining high frequency component of the low frequency component performed in the band limiting unit 221.
The high frequency signal generating unit 22B outputs the generated high frequency luminance signal Y _H to the high frequency signal adding unit 25.
As a result, the high frequency signal adding means 25 adds the high frequency luminance signal Y _H to the low frequency linear blue signal B _L and the low frequency linear red signal R _L , thereby generating an RB signal.

  The configuration of the video signal receiving device 2B according to the second embodiment of the present invention has been described above, but the present invention is not limited to the format of the present embodiment. Each means described above can be realized by a hardware configuration using a circuit, or can be realized by software. When the video signal receiving device 2B is realized by software, a general computer equipped with a CPU and a memory (not shown) can be operated by the transmission video signal conversion program that functions as the above-described units.

[Second Embodiment: Operation of Video Signal Transmission System]
Next, the operation of the video signal transmission system S _B according to the second embodiment of the present invention. In the following, the operation of the video signal transmitting apparatus 1B and the operation of the video signal receiving apparatus 2B will be described sequentially.

[Operation of video signal transmitter]
First, the operation of the video signal transmitting apparatus 1B will be described with reference to FIG. 11 (refer to FIGS. 8 and 9 as appropriate).

First, the video signal transmitting apparatus 1B inputs a video signal from the outside by an input unit (not shown) (step S20). This video signal is a three-primary color signal (RGB signal) which is a linear signal.
Then, the video signal transmitting apparatus 1B generates the luminance signal Y by mixing the RGB signals input in step S20 at a predetermined mixing ratio by the luminance signal generating means 10 (step S2). Specifically, the luminance signal generation unit 10 generates the luminance signal Y by the above equation (2).

Then, the video signal transmitting apparatus 1B extracts a predetermined low frequency component (G _L , B _L , R _L ) from the G signal, B signal, and R signal input in step S20 by the band limiting unit 11B. (Step S22).
The video signal transmission apparatus 1B, the high frequency signal generating unit 14, a luminance signal Y generated in step S21, to produce a high frequency luminance signal Y _H, which is a high-frequency component of the luminance signal Y (step S23) .

Further, the video signal transmitting apparatus 1B uses the down-sampling means 12 in advance from the signal (B _L , R _L ) extracted in step S22 in the transmission format (4: 2: 2 format, 4: 2: 0 format, etc.) A signal (B _LD , R _LD ) down-sampled at a predetermined sampling interval (down-sampling ratio) is generated (step S24).
The video signal transmission apparatus 1B, the high frequency signal adding means 15, to the low frequency linear green signal G _L extracted in step S22, by adding the high-frequency luminance signal Y _H generated at the step S23, linear signal A luminance added green signal (G _L + Y _H ) is generated (step S25).

Then, the video signal transmitting apparatus 1B uses the nonlinear conversion unit 13B to generate the luminance-added green signal (G _L + Y _H ) generated in step S25 and the low-frequency component signal (B _LD , R _LD ) down-sampled in step S24. ) Is converted into a non-linear signal by non-linear conversion (step S26). That is, the nonlinear conversion means 13B converts the luminance added green signal (G _L + Y _H ) into a nonlinear luminance added green signal (G _L + Y _H ) ^α, and converts the low frequency linear blue signal B _LD to the low frequency nonlinear blue signal B _LD ^α . The low-frequency linear red signal R _LD is converted into a low-frequency nonlinear red signal R _LD ^α .

Thereafter, the video signal transmitting apparatus 1B uses the output means (not shown) to output the non-linear luminance addition green signal (G _L + Y _H ) ^α converted in step S26, the low-frequency non-linear blue signal B _LD ^α, and the low-frequency non-linear red signal. R _LD ^α is output as a transmission video signal to the video signal receiving device 2B via the transmission line N (step S27).
Through the above operation, the video signal transmitting apparatus 1B can add the high frequency component of the luminance signal to one of the color signals of the low frequency component and transmit it to the video signal receiving apparatus 2.

[Operation of video signal receiver]
Next, the operation of the video signal receiving apparatus 2 will be described with reference to FIG. 12 (refer to FIGS. 8 and 10 as appropriate).

First, the video signal receiving device 2B is connected to the non-linear luminance addition green signal (G _L + Y _H ) ^α that is a video signal for transmission from the video signal transmitting device 1B via the transmission path N by input means (not shown). Then, the low-frequency nonlinear blue signal B _LD ^α and the low-frequency nonlinear red signal R _LD ^α are input (step S30).

The video signal receiving apparatus 2B, the linear transformation unit 20B, the non-linear luminance addition green signal _(G L _{+ Y} H) input in step S30 ^alpha, low-pass linear blue signal _{B LD} ^alpha and low nonlinear red _{R LD} ^alpha by providing an inverse characteristic of the nonlinear conversion, the signals, respectively linear luminance addition green signal _(G L _{+ Y} H), converted to the low frequency linear blue signal _{B LD} and a low linear red _{R LD} (step S31). This linear luminance addition green signal (G _L + Y _H ) is an output G signal.

Then, the video signal receiving device 2B uses the high frequency signal generation unit 22B to convert the high frequency luminance signal Y _H that is a high frequency component of the luminance signal from the linear luminance addition green signal (G _L + Y _H ) converted in step S31. Is generated (step S32).

In addition, the video signal receiving device 2B uses the up-sampling unit 23 to increase the low-frequency linear blue signal B _LD and the low-frequency linear red signal R _LD converted in step S31 so that the same number of samples and pixel structure as the luminance signal are obtained. Sample (step S33).

The video signal receiving apparatus 2B, the high frequency signal adding means 25B, the low-pass linear blue signal B _L and a low linear red R _L which is upsampled at step S33, the high frequency luminance signal Y _H generated at the step S32 Is added to generate an RB signal (step S34).

Thereafter, the video signal receiving device 2B outputs the G signal generated in step S31 and the RB signal generated in step S34 as video signals by output means (not shown) (step S35).
Through the above-described operation, the video signal receiving device 2B causes the non-linear luminance addition green signal (G _L + Y _H ) ^α output from the video signal transmitting device 1B, the low-frequency nonlinear blue signal B _LD ^α, and the low-frequency nonlinear red signal R. A video signal of the three primary color signals (RGB signals) can be generated from the _LD ^α .

As described above, the video signal transmission system S (S _B ) generates the luminance signal Y from the linear RGB signal in the video signal transmission device 1 (1B) and performs nonlinear conversion on the luminance signal Y. A non-linear luminance signal ^Yα is generated. This non-linear luminance signal Y ^alpha, in the video signal receiving device 2 (2B), by applying a inverse characteristic of the nonlinear conversion, it is possible to correctly reproduce the luminance signal Y.

Also, the video signal transmission system S (S _B ) converts the linear color signal into a non-linear signal by non-linear conversion after band limiting and down-sampling in the video signal transmitting apparatus 1 (1B). Since this nonlinear signal is returned to a linear signal by the inverse characteristic of the nonlinear transformation on the receiving side, it becomes possible to reproduce the color with low distortion.

Further, since the video signal transmission system S (S _B ) does not use the color difference signal in the video signal transmission apparatus 1 (1B), there is no processing for performing nonlinear conversion on the color difference signal as in the conventional case, and the high saturation portion of the video signal. The SN ratio can be prevented from decreasing.

S, _{S B} video signal transmission system 1,1B video signal transmission apparatus 10 luminance signal generating means 11,11B band limiting means 12 down-sampling means 13,13B nonlinear conversion unit 14 and high frequency signal generating unit 141 band limiting means 142 subtracting means 15 High-frequency signal adding means 2, 2B Video signal receiving device 20, 20B Linear conversion means 21 Band-limiting means (second band-limiting means)
22, 22B High-frequency signal generating means 221 Band limiting means 222 Subtracting means 23 Up-sampling means 24 Color signal generating means 25, 25B High-frequency signal adding means 3 Transmission signal converting means 30 Linear converting means 31 Band limiting means 32 Down-sampling means 33 Nonlinear conversion means 34 Color difference signal generation means 4 Received signal conversion means 40 Color signal generation means

Claims (5)

In a video signal transmitting apparatus for generating and transmitting a video signal for transmission from first to third color signals which are input three primary color signals,
Luminance signal generating means for generating a linear luminance signal that is a linear luminance signal by mixing the color signals of the three primary colors that are linear signals at a predetermined mixing ratio;
Band limiting means for extracting a signal of a low frequency component from the first color signal and the second color signal;
Down-sampling means for down-sampling each signal extracted by the band limiting means at a predetermined sampling interval;
The linear luminance signal generated by the luminance signal generating means is converted into a non-linear luminance signal by non-linear conversion, and the low-frequency linear first color signal and the low-frequency linear second color signal down-sampled by the down-sampling means are reduced. A non-linear conversion means for converting into a non-linear first color signal and a low non-linear second color signal,
A video signal transmission characterized in that the non-linear luminance signal, the low-frequency non-linear first color signal and the low-frequency non-linear second color signal converted by the non-linear conversion unit are output as the video signal for transmission via an output unit. apparatus. In order to generate a video signal for transmission from the first to third color signals, which are input three primary color signals,
Luminance signal generating means for generating a luminance signal that is a linear luminance signal by mixing the color signals of the three primary colors that are linear signals at a predetermined mixing ratio;
Band limiting means for extracting a signal of a low frequency component from the first color signal and the second color signal;
Down-sampling means for down-sampling each signal extracted by the band limiting means at a predetermined sampling interval;
The linear luminance signal generated by the luminance signal generating means is converted into a non-linear luminance signal by non-linear conversion, and the low-frequency linear first color signal and the low-frequency linear second color signal down-sampled by the down-sampling means are reduced. Functioning as non-linear conversion means for converting into a non-linear first color signal and a low non-linear second color signal,
Transmission video characterized in that the non-linear luminance signal, low-frequency non-linear first color signal and low-frequency non-linear second color signal converted by the non-linear conversion device are output as the video signal for transmission via an output device. Signal generation program. A non-linear luminance signal obtained by non-linear conversion of luminance signals generated from the first to third color signals, which are three primary color signals, and a low frequency component extracted from the first color signal and the second color signal, and then non-linear A video signal receiving device that receives the converted low-frequency nonlinear first color signal and the low-frequency nonlinear second color signal as a video signal for transmission, and converts the received signal into a color signal,
By giving the inverse characteristic of the nonlinear conversion on the transmission side, the nonlinear luminance signal is converted into a linear luminance signal, and the low-frequency nonlinear first color signal and the low-frequency nonlinear second color signal are respectively converted into the low-frequency linear first color. Linear conversion means for converting the signal into a low-pass linear second color signal;
Band limiting means for extracting a low frequency component from the linear luminance signal converted by the linear conversion means,
Up-sampling means for up-sampling the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means so as to have the same sample number and pixel structure as the linear luminance signal;
A low-pass linear third color signal is generated from the low-pass linear luminance signal extracted by the band limiting unit and the low-pass linear first color signal and the low-pass linear second color signal up-sampled by the up-sampling unit. Color signal generating means;
High-frequency signal generating means for generating a high-frequency luminance signal that is a high-frequency component of the linear luminance signal from the linear luminance signal;
The first to third color signals which are the color signals by adding the high frequency luminance signal to the low frequency linear first color signal, the low frequency linear second color signal, and the low frequency linear third color signal. High-frequency signal adding means for generating
A video signal receiving apparatus comprising: A non-linear luminance signal obtained by non-linear conversion of luminance signals generated from the first to third color signals, which are three primary color signals, and a low frequency component extracted from the first color signal and the second color signal, and then non-linear In order to receive the converted low-pass nonlinear first color signal and the low-pass nonlinear second color signal as video signals for transmission and convert them into color signals,
By giving the inverse characteristic of the nonlinear conversion on the transmission side, the nonlinear luminance signal is converted into a linear luminance signal, and the low-frequency nonlinear first color signal and the low-frequency nonlinear second color signal are respectively converted into the low-frequency linear first color. Linear conversion means for converting the signal into a low-frequency linear second color signal;
Band limiting means for extracting a low frequency component from the linear luminance signal converted by the linear conversion means,
Up-sampling means for up-sampling the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means so as to have the same sample number and pixel structure as the linear luminance signal;
A low-pass linear third color signal is generated from the low-pass linear luminance signal extracted by the band limiting unit and the low-pass linear first color signal and the low-pass linear second color signal up-sampled by the up-sampling unit. Color signal generating means,
High-frequency signal generating means for generating a high-frequency luminance signal that is a high-frequency component of the linear luminance signal from the linear luminance signal,
The first to third color signals which are the color signals by adding the high frequency luminance signal to the low frequency linear first color signal, the low frequency linear second color signal, and the low frequency linear third color signal. High-frequency signal adding means for generating
A video signal conversion program for transmission characterized in that it functions as: A video signal transmitting device that generates and transmits a video signal for transmission from first to third color signals that are color signals of three primary colors, and a video that receives the video signal and converts the video signal into the color signal A video signal transmission system comprising a signal receiving device,
The video signal transmission device includes:
Luminance signal generating means for generating a linear luminance signal that is a linear luminance signal by mixing the color signals of the three primary colors that are linear signals at a predetermined mixing ratio;
Band limiting means for extracting a signal of a low frequency component from the first color signal and the second color signal;
Down-sampling means for down-sampling each signal extracted by the band limiting means at a predetermined sampling interval;
The linear luminance signal generated by the luminance signal generating means is converted into a non-linear luminance signal by non-linear conversion, and the low-frequency linear first color signal and the low-frequency linear second color signal down-sampled by the down-sampling means are reduced. A non-linear conversion means for converting into a non-linear first color signal and a low non-linear second color signal,
The non-linear luminance signal, low-frequency non-linear first color signal and low-frequency non-linear second color signal converted by the non-linear conversion means are used as the video signal for transmission,
The video signal receiving device is:
By giving the inverse characteristic of the nonlinear conversion on the transmission side, the nonlinear luminance signal is converted into a linear luminance signal, and the low-frequency nonlinear first color signal and the low-frequency nonlinear second color signal are respectively converted into the low-frequency linear first color. Linear conversion means for converting the signal into a low-pass linear second color signal;
Second band limiting means for extracting a low frequency component from the linear luminance signal converted by the linear conversion means;
Up-sampling means for up-sampling the low-frequency linear first color signal and the low-frequency linear second color signal converted by the linear conversion means so as to have the same sample number and pixel structure as the linear luminance signal;
From the low-frequency linear luminance signal extracted by the second band limiting means and the low-frequency linear first color signal and low-frequency linear second color signal up-sampled by the up-sampling means, a low-frequency linear third color signal is obtained. Color signal generating means for generating
High-frequency signal generating means for generating a high-frequency luminance signal that is a high-frequency component of the linear luminance signal from the linear luminance signal;
The first to third color signals which are the color signals by adding the high frequency luminance signal to the low frequency linear first color signal, the low frequency linear second color signal, and the low frequency linear third color signal. High-frequency signal adding means for generating
A video signal transmission system comprising:

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