JP5879120B2 - Video signal processing apparatus, vector scope, and program - Google Patents

Description

The present invention relates to a video signal processing device, a vector scope , and a program.

  The color indicated by the video signal has been measured by a vectorscope. The vector scope defines a two-dimensional coordinate plane in which color difference signals are assigned to orthogonal coordinate axes, and visually displays the color indicated by the video signal to be measured based on the position of the point on the two-dimensional coordinate plane (for example, Patent Documents 1 and 2).

In recent years, such as “4K × 2K images” and “Super Hi-Vision”, video systems that display large screen digital imagery (LSDI) exceeding the number of pixels of HDTV (high definition television) systems. Has been developed.
The basic system parameters of video signals in LSDI have already been standardized and the specifications have been disclosed (ITU-R (International Telecommunication Union Radio communications Sector) Recommendation BT.1769 (hereinafter referred to as “ITU-R BT. 1769 "))).

Furthermore, a video system (UHDTV (Ultra high definition television) system) that displays an ultra-high definition image is being developed (for example, see Non-Patent Documents 1 and 2).
The system parameters of video signals in the UHDTV system have already been standardized and the specifications have been disclosed (see SMPTE (Society of Motion Picture and Television Engineers) 2036 (2007)). For example, in colorimetry (color system) in SMPTE 2036, ITU-R Recommendation BT. 709 (hereinafter referred to as “ITU-R BT.709”). Cited ITU-R BT. 709 defines the color gamut of the current HDTV system. Therefore, the range of the color gamut that can be expressed in SMPTE 2036 (2007) is limited to the same range as the color gamut of the current HDTV system.

In addition, in the new video system, not only the number of displayable pixels is increased, but also the range of the color gamut that can be expressed is increasing. For example, ITU-R BT. 709 (hereinafter referred to as “conventional color gamut”), an “extended color space” that defines a wider color gamut as a displayable area is applied to an LSDI video system.
In the case of an LSDI video system, ITU-R BT. In the colorimetry (color system) in 1769, ITU-R Recommendation BT. 1361 (hereinafter referred to as “ITU-R BT. 1361”) is cited. ITU-R BT. 1361 defines a color gamut wider than the color gamut of a video system such as the current HDTV system (“conventional color gamut”) as a displayable area. This ITU-R BT. 1361 in the range of “conventional color gamut”, ITU-R BT. It is expressed using the same value as 709. On the other hand, in the range exceeding the “conventional color gamut”, ITU-R BT. It is expressed using a value not defined in 709 (a negative number or a value exceeding 1). Thus, ITU-R BT. When the displayable area is expanded by the “extended color space” as in 1361, the ITU-R BT. It could be handled in the same way as the information of 709. In conventional video systems, even if the displayable area is wider than the “conventional color gamut”, the information in the “conventional color gamut” range is handled in common between different video systems. I was able to.
There is a method of widening the displayable area by a method different from the above “extended color space”. For example, “Adobe RGB” that defines a wide color gamut in fields such as printing and digital cameras, and the digital cinema standard (SMPTE RP 431-2) are known. In the method of widening the displayable area according to the standards that define these color systems, the chromaticity points of the three primary colors of RGB are arranged at positions corresponding to the respective standards. Therefore, if the color systems are different, even if the same color is indicated, the information indicating the color may have a different value for each color system.

JP-A-5-122734

Masaoka, “Super Hi-Vision Color System”, [online], October 2010, NHK Technical Research Institute, Giken News, No. 60, [Search May 2, 2011], Internet (URL: http: //www.nhk.or.jp/strl/publica/giken_dayori/jp2/rd-1003.html) Masaoka, K. Nishida, Y. Sugawara, M. Nakasu, E., "Design of Primaries for a Wide-Gamut Television Colorimetry", IEEE Transactions on Broadcasting, Volume: 56 Issue: 4, pp. 452-457, 2010.

  By the way, in conventional video systems, information in the range of “conventional color gamut” can be handled in common. Therefore, with conventional video systems, the range of the “conventional color gamut” can be measured with a vector scope even in different video systems. However, in a video system that handles video signals that have a "wide color gamut" color system that expands the display range of the "conventional color gamut", a vector scope that has the "conventional color gamut" color system. There is a problem that it is difficult to continue the conventional operation of measuring using the same scale as that displayed on the screen. For example, when a vector scope whose color system is “conventional color gamut” and a color indicated by a video signal whose color system is “wide color gamut” is measured and displayed, the point (color (Degrees) are displayed at different positions. Here, it is assumed that a video signal whose color system is “wide color gamut” is measured. When measuring video signals whose color system is “wide color gamut”, it is possible to measure using a scale different from the scale displayed on the screen of the vector scope whose color system is “conventional color gamut”. I need it. Thus, when changing the scale of the measurement system, there is a problem that it is difficult to continue the conventional operation.

An object of the present invention is to solve the above-described problem, in measuring the color indicated by a video signal having a wider color gamut than the color gamut based on the color gamut of the color system (conventional color gamut). Another object of the present invention is to provide a video signal processing apparatus, a vector scope , and a program for measuring using the same scale as the measurement of the color indicated by the video signal of the color gamut.

[1] [2] The present invention has been made to solve the above-described problems, and the video signal processing apparatus according to one aspect of the present invention provides a first color system in which the reference three primary colors of the video signal are different. For the second color system, chromaticity points on the chromaticity diagram corresponding to the reference three primary colors RGB of the first color system are chromaticity points corresponding to the reference three primary colors RGB of the second color system. And a video signal expressed in the first color system when the input video signal is a signal expressed in the second color system. A scale conversion unit that performs scale conversion, and the scale conversion processing unit linearizes the input video signal to generate a first video signal; and the generated first video signal The reference three primary colors of the video signal are designated as the reference three primary colors of the second color system. A first matrix conversion processing unit for converting from GB to the reference three primary colors RGB of the first color system and converting to a second video signal having the three primary colors RGB as components, and a component of the second video signal A non-linearization processing unit that performs non-linear processing to generate a third video signal having three primary colors RGB as components, and from the third video signal, the reference three primary colors RGB of the first color system are set as reference three primary colors. And a second matrix conversion processing unit for generating a fourth video signal having the luminance signal and the color difference signal of the first color system that do not satisfy the constant luminance principle as components.

  According to this aspect, in the scale conversion processing unit, the linearization processing unit linearizes the input video signal to generate the first video signal. The first matrix conversion processing unit converts the reference three primary colors of the generated first video signal from the reference three primary colors RGB of the second color system to the reference three primary colors RGB of the first color system. At the same time, it is converted into a second video signal having the three primary colors RGB as components. The non-linearization processing unit performs non-linear processing on each component of the second video signal to generate a third video signal having the three primary colors RGB as components. Then, the second matrix conversion processing unit generates, from the third video signal, a fourth video signal whose components are the second luminance signal by the first color system that does not satisfy the constant luminance principle and the color difference signal. Thus, the video signal processing device can measure the color indicated by the input video signal based on the fourth video signal.

  [3] In the video signal processing apparatus according to one aspect of the present invention, the linearization processing unit may respond to the input video signal according to the constant luminance principle when the input video signal is transmitted while satisfying the constant luminance principle. When the input video signal is transmitted without satisfying the constant luminance principle, linearization processing is performed on the input video signal according to the non-constant luminance principle, and the input video signal is based on the input video signal. The first video signal having the three primary colors RGB as components is generated.

  According to this aspect, when the input video signal is transmitted while satisfying the constant luminance principle, the linearization processing unit performs linearization processing on the input video signal according to the constant luminance principle. When the input video signal is transmitted without satisfying the constant luminance principle, the linearization processing unit performs a linearization process according to the non-constant luminance principle for the input video signal. In any of the above cases, the linearization processing unit generates a first video signal whose components are the three primary colors RGB based on the input video signal. As a result, the linearization processing unit can detect whether the input video signal is transmitted while satisfying the constant luminance principle or the input video signal is transmitted without satisfying the constant luminance principle. Linearization processing according to the signal can be performed, and a first video signal based on the input video signal can be generated.

  [4] A vector scope according to an aspect of the present invention associates the two components of the color difference signal with the orthogonal coordinate axes in the two-dimensional coordinate plane on which the orthogonal coordinate axes are shown, with the video signal processing device of the invention. And a vector display generation unit for generating a display screen.

  According to this aspect, the vector display generation unit includes the video signal processing device of the above invention and a vector display generation unit. Based on the color difference signal of the fourth video signal generated by the video signal processing device, the vector display generation unit associates the two components of the color difference signal with the orthogonal coordinate axes in a two-dimensional coordinate plane on which the orthogonal coordinate axes are indicated. Display screen can be generated.

[5] A program according to an aspect of the present invention is a program for causing a computer to function as one of the video signal processing devices .

  As described above, according to the present invention, in the measurement of the color indicated by the video signal whose color gamut is wider than the reference color gamut, the image of the reference color gamut It is possible to measure using the same scale as the measurement of the color indicated by the signal.

It is a block diagram which shows the vector scope by 1st Embodiment of this invention. It is a figure which shows the color gamut of the video signal made into a measuring object. It is a figure which shows the example shown on the display screen of a vector scope, and a measurement result. It is a figure which shows the relationship between the item which shows the characteristic of a video signal, and the value of the variable of the item. 4 is a flowchart showing a procedure of conversion processing in a scale conversion unit 20. It is a figure which shows the data flow in the conversion process in the case of "wide color gamut and constant luminance mode". It is a figure which shows the data flow in the conversion process in the case of "wide color gamut and non-constant luminance mode". It is a block diagram which shows the vector scope by 2nd Embodiment of this invention. It is a figure which shows the relationship between the item which shows the characteristic of a video signal, and the value of the variable of the item. It is a figure which shows the data flow in the conversion process in the case of "wide color gamut and constant luminance mode". It is a figure which shows the data flow in the conversion process in the case of "wide color gamut and non-constant luminance mode".

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a functional configuration of the vector scope according to the present embodiment. The vector scope 1 shown in FIG. 1 is supplied with an externally supplied video signal and a synchronization signal synchronized with the video signal, and measures and displays the color of the supplied video signal. When a signal based on a reference test signal (color bar signal) is supplied to the vector scope 1 as an input video signal, the vector scope 1 displays the color information of the color indicated by the measured video signal. Display a screen to measure color reproducibility based on.

  Here, a video signal to be measured by the vector scope 1 will be described with reference to FIG. The vector scope 1 uses a video signal of an HDTV system and a video signal of a video system (such as a UHDTV system) that displays an ultra-high-definition image that greatly exceeds the number of pixels of a display screen displayed by the HDTV system. FIG. 2 is a diagram showing the color gamut of the video signal to be measured. In FIG. 2, the difference in color gamut between HDTV and UHDTV is shown by the XY chromaticity diagram of the XYZ color space of CIE (International Lighting Commission). This xy chromaticity diagram shows the distribution of chromaticity points displayed by the video signal. In the xy chromaticity diagram, the inner range of the primary color spectrum locus indicated by the horseshoe shape indicates the color range that can be displayed by the combination of the primary colors (stimulus values) on the spectrum locus. For example, when displaying with a combination of three primary colors included in the reference primary colors, three points are selected inside the spectrum locus of the primary colors indicated by a horseshoe shape in the xy chromaticity diagram. The three selected points indicate chromaticity points that each define a color gamut. Further, a triangular range indicated by three chromaticity points (chromaticity points of the three primary colors of RGB) indicates a range in which chromaticity points that can be displayed by a combination of these chromaticity points are distributed.

  The color gamut range shown in FIG. 2 differs depending on the color system. For example, in the case of HDTV (ITU-R BT.709), three points (chromaticity points) are selected inside the horseshoe shape. Hereinafter, the color gamut when three points (chromaticity points) are selected inside the horseshoe shape is referred to as “conventional color gamut”. In order to make the displayable color gamut wider than the “conventional color gamut”, the area of this triangle is increased. A color gamut such as UHDTV in which the range of colors that can be displayed is wider than the “conventional color gamut” is called a “wide color gamut”. For example, in UHDTV, in order to widen the area of this triangle, three points (RGB three primary colors (the chromaticity points of the three primary colors RGB of the second color system)) on the spectrum locus of the primary color indicated by the horseshoe shape are defined. select.

  2 (a) and 2 (b), the chromaticity points of the RGB three primary colors (reference three primary colors RGB of the first color system) in the case of the “conventional color gamut” are indicated by the vertices of a triangle with the symbol HDTV. The chromaticity points of the RGB three primary colors in the case of “wide color gamut” are indicated by the vertices of a triangle with the symbol UHDTV. Further, FIG. 2A shows a distribution of chromaticity points corresponding to each color patch in a specific color chart in a general color chart. Since the colors of each color patch in this color chart indicate the colors that can be normally displayed, most of the chromaticity points of each color patch are placed within the "conventional color gamut" range. Is done. FIG. 2B shows the chromaticity distribution of Pointer's color. As shown in FIG. 2B, many Pointer's color chromaticity points cannot be arranged within the range of the HDTV color gamut, but protrude beyond the range of the UHDTV color gamut. Most chromaticity points can be arranged within the range.

By the way, in the case of “wide color gamut”, since the range of colors that can be displayed becomes wider than in the case of “conventional color gamut”, it is possible to identify the positions of more chromaticity points than in the “conventional color gamut”. I need it. Therefore, information indicating the position of each chromaticity point in the case of the “conventional color gamut” and the case of the “wide color gamut” is different from each other. Therefore, when measurement is performed under the same conditions, a conversion process corresponding to the difference according to the difference in the color system is required.
In addition to the difference in color system, the video signal transmission method affects the arrangement of chromaticity points. There are two video signal transmission systems, one of which is a transmission system using the “non-constant luminance mode” and the other of which is a transmission system using the “constant luminance mode”. Therefore, when measurement is performed under the same conditions, a conversion process corresponding to the difference according to the difference in transmission method is required.
As described above, the position of the chromaticity point indicated by the information of the video signal differs depending on the combination of the color system corresponding to the video system and the transmission method of the video signal. Therefore, in the vector scope 1, when measuring the color indicated by the video signal to be measured, the measurement is switched to the measurement mode setting corresponding to the combination of the color system and the transmission method. The vector scope 1 has “conventional color gamut / non-constant luminance mode”, “wide color gamut / constant luminance mode”, and “wide color gamut / non-constant luminance mode” according to the type of video signal to be measured. The color reproducibility is measured for each video signal by switching the three modes. These three modes will be described in order.

“Conventional color gamut / non-constant luminance mode” is a video signal in which the video signal supplied as the input video signal is transmitted without satisfying the constant luminance principle, and the color gamut in the color system of the input video signal is In this mode, measurement is performed when the color gamut (first color gamut) is set as a reference. The “reference color gamut” refers to, for example, ITU-R BT. 709 is a color gamut defined by 709.

The “wide color gamut / constant luminance mode” is a video signal that is transmitted as an input video signal satisfying the constant luminance principle, and the color gamut in the color system of the input video signal is the reference. In this mode, conversion processing is performed when the color gamut (first color gamut, “conventional color gamut”) is a wide color gamut (second color gamut).

“Wide color gamut / non-constant luminance mode” is a video signal that is transmitted as an input video signal without satisfying the constant luminance principle, and the color gamut in the color system of the input video signal is This is a mode for performing conversion processing when the color gamut is widened (second color gamut) from the standard color gamut (first color gamut, “conventional color gamut”).

In the vector scope 1, a mode corresponding to the type of video signal is set. In the vector scope 1, the mode is switched according to the type of the video signal, but the measurement of the color indicated by the video signal in each mode is performed based on a scale common to each mode.
FIG. 3 is a diagram showing an example of the scale and measurement result (HDTV color bar signal) shown on the display screen of the vector scope. FIG. 3 shows an orthogonal scale (coordinate axes) on the two-dimensional coordinate plane shown on the display screen of the vector scope. The two components of the color difference signal are associated with orthogonal scales (coordinate axes), respectively, and the chromaticity indicated by the two components of the color difference signal is shown as a point on the two-dimensional coordinate plane. Note that the scale shown in FIG. 3 has been used so far when measuring the color reproducibility of a video signal. The measurement of the color reproducibility of the video signal has been operated so as to measure based on the scale shown in FIG. Therefore, since the measurement based on this scale is common, the user can easily evaluate the measurement result displayed based on this scale. The video signal measured for color reproducibility using this scale is a video signal in the “conventional color gamut / non-constant luminance mode”. In the present embodiment, the vector scope 1 also measures the video signal of the HDTV system and the video signal of the video system that displays an ultra-high-definition image that greatly exceeds the number of pixels of the display screen displayed by the HDTV system. The scale shown in FIG. 3 is applied. Therefore, when measuring the color reproducibility of the video signal of “wide color gamut / constant brightness mode” or “wide color gamut / non-constant brightness mode”, “wide color gamut / constant brightness mode”, or By converting the video signal of “wide color gamut / non-constant luminance mode” into the video signal of “conventional color gamut / non-constant luminance mode”, the coordinate system (scale) shown in FIG. Enables measurement of signal color reproducibility.
Hereinafter, a vector scope that performs conversion processing from a video signal in “wide color gamut / non-constant luminance mode” or “wide color gamut / non-constant luminance mode” to a video signal in “conventional color gamut / non-constant luminance mode”. 1 will be described in order of functional configuration and processing.

  Returning to FIG. 1, the functional configuration of the vector scope 1 will be described. The vector scope 1 includes an input conversion unit 11, a reproduction output unit 12, a clock distribution unit 13, a scale conversion unit 20, a video switching unit 30, a waveform display generation unit 41, a vector display screen generation unit 42, an RGB waveform screen generation unit 43, A status screen generation unit 44, a screen selection synthesis unit 45, a display unit 50, an operation input detection unit 60, and a control unit 80 are provided.

An input video signal is supplied from the outside to the input conversion unit 11, and timing information distributed by the clock distribution unit 13 is supplied from the clock distribution unit 13. The input video signal is a video signal of an HDTV system and a video signal of a video system (such as a UHDTV system) that displays an ultra-high definition image. The input conversion unit 11 extracts an input video signal input from the outside in synchronization with the timing information distributed by the clock distribution unit 13. When the input video signal is an HDTV system video signal, the input conversion unit 11 sends the extracted video signal (Y′Cb′Cr ′ (first color system)) to the reproduction output unit 12 and the video switching unit 30. Supply. Further, when the input video signal is a video signal of a video system (such as a UHDTV system) that displays an ultra-high definition image, the input conversion unit 11 extracts the extracted video signal (Yconst'C ' _B C' _R (second Color system)) or video signal (Y′C ′ _B C ′ _R (second color system)) is supplied to the reproduction output unit 12 and the scale conversion unit 20. Furthermore, the input conversion unit 11 detects the state of the input video signal that has been input, and supplies the detection result to the control unit 80.

  The reproduction output unit 12 is supplied with the input video signal extracted by the input conversion unit 11 from the input conversion unit 11, and is supplied with timing information distributed by the clock distribution unit 13 from the clock distribution unit 13. The reproduction output unit 12 supplies the input video signal extracted by the input conversion unit 11 to an externally connected device (not shown) in synchronization with the timing information distributed by the clock distribution unit 13.

 The clock distribution unit 13 is supplied with a synchronization signal synchronized with the input video signal from the outside. The clock distribution unit 13 reproduces the supplied synchronization signal and distributes it to each unit in the vector scope 1. The clock distribution unit 13 detects the state of the synchronization signal synchronized with the input video signal, and supplies the detected result to the control unit 80.

The scale conversion unit 20 converts the video signal supplied from the input conversion unit 11 according to the “wide color gamut / constant luminance mode” or the conversion process according to the “wide color gamut / non-constant luminance mode”. Do either one. The conversion process in the scale conversion unit 20 is selected according to control by the control unit 80. The scale conversion unit 20 generates a video signal (Y _N 'Cb'Cr') to be supplied to the video switching unit 30 as the “conventional color gamut / non-constant luminance mode” by the selected conversion process. The video signal (Y _N 'Cb'Cr') is expressed by the same color system (first color system) as the video signal (Y'Cb'Cr ').
In other words, the scale converter 20 of the present embodiment expresses the video signal (input video signal) supplied from the input converter 11 by the first color system (color system corresponding to the conventional color gamut). Converted to a video signal. When the video signal (input video signal) supplied from the input conversion unit 11 is a signal expressed in the second color system (color system corresponding to a wide color gamut), the first color system (conventional) Scale conversion to a video signal expressed in a color system corresponding to the color gamut). In the scale conversion unit 20, the chromaticity on the chromaticity diagram corresponding to the reference three primary colors RGB of the first color system for the first color system and the second color system in which the reference three primary colors of the video signal are different. The video signal included in the region on the chromaticity diagram in which the points are formed by chromaticity points corresponding to the reference three primary colors RGB of the second color system is the processing target.

The scale conversion unit 20 includes a linearization processing unit 21, a matrix conversion processing unit 22, a non-linearization processing unit 23, and a matrix conversion processing unit 24.
When the input video signal (input video signal) is a wide color gamut signal, the linearization processing unit 21 converts the information of the input video signal into information of the color space indicated by the GBR signal. In addition, when the input video signal is a wide color gamut signal, the input video signal may be a signal transmitted satisfying the constant luminance principle or a signal transmitted without satisfying the constant luminance principle. is there. When the input video signal is transmitted while satisfying the constant luminance principle, the linearization processing unit 21 responds to the video signal (Yconst'C ' _B C' _R ) extracted from the input video signal according to the constant luminance principle. linearization process is the (inverse gamma processing), G _{(G W,} first green signal) and R _{(R W,} the first red) and B _{(B W,} first green light) GBR to a component A signal (G _{WB WR W} , first video signal) is generated. Further, when the input video signal is transmitted without satisfying the constant luminance principle, the linearization processing unit 21 is indeterminate with respect to the video signal (Y′C ′ _B C ′ _R ) extracted from the input video signal. G (G _W , first green signal), R (R _W , first red signal) and B (B _W , first blue signal) based on the input video signal after linearization processing according to the luminance principle generating a GBR signal to component _{(G W} B _{W R W,} a first video signal) and. Thus, linearization processing section 21, a video signal is supplied, the video signal _{(Yconst'C 'B C' R)} , and, either one of the video signal (Y'C _'B C' _R) also generates a GBR signal _{(G W} B _{W R W,} a first video signal). Incidentally, GBR signal generated by the linearization processing section _{21 (G W B W R W} ) is a video signal of wide color gamut.

The matrix conversion processing unit 22 (first matrix conversion processing unit) obtains a “conventional color gamut (first gamut) from the GBR signal (G _{WB WR W} , first video signal) generated by the linearization processing unit 21. A video signal (RGB signal (R _N G _N B _N ) second video signal) having the three primary colors RGB in the color gamut) ”color system as a component is generated. In short, the matrix conversion processing unit 22 (first matrix conversion processing unit) converts the YBR signal (Y _W B _W R _W ) of “wide color gamut (second color gamut)” into the RGB signal of “conventional color gamut”. Convert as (R _N G _N B _N ). In this way, the conversion process performed by the matrix conversion processing unit 22 converts the wide color gamut GBR signal (G _W B _W R _W ) into the conventional color gamut RGB signal (R _N G _N B _N ). . As a result, the information on the color space indicated by the GRB signal (G _W B _W R _W ) in the wide color gamut is converted to the information on the color space indicated by the RGB signal (R _N G _N B _N ) in the conventional color gamut. The Thus, the matrix conversion processing unit 22 (first matrix conversion processing unit), the above GBR signal generated by the linearization processing section _{21 (G W B W R W} , a first video signal) of the second Conversion from the color system to the first color system and conversion to the RGB signals (R _N G _N B _N , second video signal) having the three primary colors RGB of the first color system as components. . Here, the first color system is, for example, a color system that can represent a color gamut that can represent the conventional color gamut, and the second color system is, for example, from the conventional color gamut. This is a color system that can express a wide color gamut.
In other words, the matrix conversion processing unit 22 uses the GBR signal (G _W B _W R _W , the first video signal) generated by the linearization processing unit 21 as an RGB signal (R _N G G) having the three primary colors RGB as components. _{N BN} , second video signal). Matrix conversion processing unit 22, together with the above conversion, the second video signal (GRB signal _{(G W B W R W)} ) including the three primary colors RGB to a reference primary color from a video signal including the first three primary colors RGB to a reference primary color ( RGB signal (R _N G _N B _N ))). Here, the video signal including the second three primary colors RGB as a reference primary color is a video signal (GRB signal (G _{WB W} R _W )) having a wide color gamut (second color gamut) as the color gamut. A video signal including the three primary colors RGB as a reference primary color is a video signal (RGB signal (R _N G _N B _N )) having a conventional color gamut (first color gamut) as a color gamut.

The non-linearization processing unit 23 performs non-linearization processing (gamma processing) on the components of the RGB signals (R _N G _N B _N , the second video signal), and performs R′G′B ′ using the three primary colors RGB as components. A signal (R _N 'G _N ' B _N ', third video signal) is generated.
Matrix conversion processing unit 24 (second matrix conversion processing unit) is, R'G'B 'signal _{(R N'} from _{G N 'B N',} third image signal), a color system that does not satisfy the constant luminance principle luminance component by _Y '(Y _N', second luminance signal) and color difference components Cb ', Cr' and Y'Cb'Cr 'signal _{(Y N'} to component Cb'Cr ', fourth video signal) Is generated. In this way, the Y′Cb′Cr ′ signal of the conventional color gamut is generated from the RGB signal of the conventional color gamut by the conversion processing sequentially performed by the non-linearization processing unit 23 and the matrix conversion processing unit 24. As a result, the scale conversion unit 20 uses the same coordinate system (scale) as the coordinate system (scale) when measuring the color reproducibility of the video signal in the conventional color gamut to “wide color gamut (second color gamut)”. It is possible to measure color reproducibility in video signals.

The video switching unit 30 controls the video signal (Y′Cb′Cr ′ signal) supplied from the input conversion unit 11 and the video signal (Y′Cb) supplied from the scale conversion unit 20 according to control from the control unit 80. One of the 'Cr' signals (Y _N 'Cb'Cr')) is selected and output.

  The waveform display generation unit 41 generates a screen showing the waveform of the video signal (Y′Cb′Cr ′ signal) supplied from the video switching unit 30. In the generated screen, the horizontal axis is the time axis, and the vertical axis is the axis indicating the amplitude indicating the luminance of the video signal. The waveform display screen generated by the waveform display generation unit 41 shows the waveform of the video signal showing the change in luminance with the passage of time.

The vector display screen generation unit 42 generates a screen indicating the color reproducibility of the video signal (Y′Cb′Cr ′ signal) supplied from the video switching unit 30. In the generated screen, a horizontal axis C _B axis, the vertical axis and C _R axis. The vector display screen generation unit 42 (vector display generation unit) determines and inputs a two-dimensional coordinate plane in which the components of the color difference signal in the Y′Cb′Cr ′ signal (fourth video signal) are respectively assigned to orthogonal coordinate axes. When a predetermined test signal is supplied as a video signal, it is indicated by the input video signal according to the distance from the point on the basis of the point on the coordinate space indicated by the value of the color difference signal component. Indicates color. Further, the vector display screen generated by the vector display screen generation unit 42 shows a vector indicating the color reproducibility of the video signal. In the generated screen, the horizontal axis may be displayed as the (BY) axis, and the vertical axis may be displayed as the (RY) axis.

  The RGB waveform screen generation unit 43 generates a screen showing each waveform of the three primary color RGB components generated by conversion from the video signal (Y′Cb′Cr ′ signal) supplied from the video switching unit 30. In the generated screen, the horizontal axis is the time axis, and the vertical axis is the axis indicating the amplitudes of the components of the three primary colors RGB. The waveform display screen generated by the RGB waveform screen generation unit 43 shows the waveform of the video signal indicating the change in luminance with the passage of time.

  Based on the status information supplied from the control unit 80, the status screen generation unit 44 generates a screen showing information related to the video signal and the synchronization signal. The information relating to the video signal shown on the status screen includes, for example, information such as the type and state of the input video signal and information such as the type and state of the synchronization signal.

  The screen selection / synthesis unit 45 displays a video signal supplied from the video switching unit 30 under the control of the control unit 80, a waveform display generation unit 41, a vector display screen generation unit 42, and an RGB waveform screen generation unit. 43. A specific screen is selected from the screens generated by the status screen generation unit 44, respectively. Further, the screen selection combining unit 45 combines the selected screens. The screen synthesized by the screen selection / synthesis unit 45 is a synthesized screen based on an N-divided screen (for example, a screen such as two-divided or four-divided) in which reduced screens are arranged and displayed, or a specific image selected. There is a composition screen (picture-in-picture screen) that reduces the size of the image and overlays it on a range where other images are displayed. The screen selection synthesis unit 45 supplies the selected screen or the synthesized screen to the display unit 50.

  The display unit 50 displays the screen selected by the screen selection combining unit 45 or the screen combined by the screen selection combining unit 45.

  The operation input detection unit 60 detects an operation by a user and supplies operation information corresponding to the detection result to the control unit 80.

  The operation information supplied to the control unit 80 includes a signal type of an externally input video signal, identification information indicating an input signal terminal, control information for identifying information to be displayed on the display unit 50, and the like. The control unit 80 generates a control signal for controlling each unit based on operation information corresponding to the operation by the user supplied from the operation input detection unit 60, and supplies the generated control signal to each unit to be controlled. . For example, the control unit 80 controls the input conversion unit 11 according to the signal type and signal terminal selected based on the operation information according to the operation by the user, and according to the signal type of the input video signal. Processing and input signal terminals are switched. The control unit 80 controls the scale conversion unit 20 according to the signal type selected based on the operation information corresponding to the operation by the user, and according to the signal type of the video signal supplied from the input conversion unit 11. Conversion processing (video signal processing) is performed.

  When the input video signal is in the “wide color gamut / constant luminance mode”, the control unit 80 causes the linearization processing unit 21 in the scale conversion unit 20 to perform linear conversion, and the “wide color gamut / non-constant luminance mode”. In this case, the linearization processing unit 21 in the scale conversion unit 20 generates an output video signal without performing linear conversion. The control unit 80 controls the video switching unit 30 according to the signal type selected based on the operation information corresponding to the operation by the user, and switches the video signal supplied by the video switching unit 30. When the input video signal is in the “wide color gamut / constant luminance mode” or the “wide color gamut / non-constant luminance mode”, the control unit 80 converts the video signal generated by the scale conversion unit 20 into the video switching unit 30. In the case of the “conventional color gamut / non-constant luminance mode”, the video switching unit 30 selects the video signal supplied from the input conversion unit 11. The control unit 80 controls the screen selection combining unit 45 in response to a display screen selection request selected based on the operation information corresponding to the operation by the user, and selects and combines the screens to be selected and combined in the screen selection combining unit 45. Switch information. The control unit 80 collects information detected by the input conversion unit 11, the clock distribution unit 13, the waveform display generation unit 41, the vector display screen generation unit 42, the RGB waveform screen generation unit 43, and the like, and collects the collected information. This is supplied to the status screen generation unit 44.

Next, a case where a wide color gamut video signal is handled as a conventional color gamut video signal will be described. With reference to FIG. 4, an example of each signal and conversion in this embodiment will be described. FIG. 4 is a diagram showing the relationship between the item indicating the characteristics of the video signal and the value of the variable of the item. The target video signal shown in FIG. 4 is represented by a signal format including a component (R ′, G ′, B ′) or (Y ′, C ′ _B, C ′ _R ). The photoelectric conversion characteristics are determined by a relational expression indicating the relationship between E and E ′. E is a value obtained by normalizing a voltage value proportional to the input light intensity detected in each channel of the camera with reference white. E ′ is a primary color signal obtained by this nonlinear processing. α and β are variables determined according to the number of quantization bits. For example, when the quantization bit number is 10 bits, α = 1.0099 and β = 0.018, and when the quantization bit number is 12 bits, α = 1.993 and β = 0.0181. Good.

  Next, a signal equation of the luminance signal is shown. The signal equation shown in this figure is for the case of transmission satisfying the constant luminance principle. Equation (1) shows a signal equation of a luminance signal when transmitted while satisfying the constant luminance principle.

Yconst '= (rR + gG + bB)' (1)

  In Expression (1), Yconst ′ represents a luminance value when transmission is performed while satisfying the constant luminance principle. “′ (Prime)” indicates the result of the non-linear processing (gamma correction processing). R, G, and B respectively indicate the components of the three primary colors RGB of the video signal having a wide color gamut. “r”, “g”, and “b” indicate coefficients to be respectively multiplied by the components of the three primary colors RGB of the wide color gamut video signal. As shown in this equation (1), Yconst ′ is a non-linearization process (gamma correction process) obtained by adding a product obtained by multiplying each component of the three primary colors RGB of a wide color gamut by a coefficient. ) To get.

  On the other hand, the signal equation of the luminance signal when transmitted without satisfying the constant luminance principle is shown in Equation (2).

Y ′ = rR ′ + gG ′ + bB ′ (2)

  In equation (2), Y ′ represents the value of the luminance when transmitted without satisfying the constant luminance principle. As shown in this equation (2), Y ′ is a non-linear process (gamma correction process) for each of the three primary colors RGB of the video signal having a wide color gamut, and a coefficient is added to the result. It is obtained by adding the products multiplied by each.

  As described above, the luminance signal signal equations shown in the equations (1) and (2) each include nonlinear processing. Therefore, a calculation error due to the difference in the calculation method of the nonlinear processing described above may occur between the Yconst ′ value and the Y ′ value calculated by the expressions (1) and (2).

  Returning to FIG. 4, the signal equation of the color difference signal is shown.

C ′ _B = (B′−Y ′) / K _B (3)

C ′ _R = (R′−Y ′) / K _R (4)

In the formula (3), Equation (4), _{K B} and _{K R} represents a constant determined in advance.
Note that the quantization characteristics of the luminance signal and the color difference signal and the quantization characteristics of the primary color signal in this embodiment may be determined according to the standard of the HDTV system, for example.

By the way, in a video signal of a specific color system, if the chromaticity point based on the information of the video signal is simply arranged as a chromaticity point on a coordinate system with a different color system, the position of the chromaticity point can be determined. It may not be placed in the correct position. If the chromaticity point is not arranged at the correct position, the displayable area of the chromaticity point indicated by the position of the chromaticity point is not displayed correctly. In such a case, the operation of measuring the color reproducibility of the video signal of the specific color system according to the coordinate system based on a different color system cannot be performed. For example, a case will be described in which the specific color system video signal is a wide color gamut video signal and the different color system video signal is a conventional color gamut video signal. As described above, until now, measurement of color reproducibility in a video signal of a conventional color gamut has been performed according to a coordinate system based on color difference signals (C _B , C _R ). However, when measuring color reproducibility in a wide color gamut video signal, the chromaticity points are not arranged at the correct positions as described above, and there is also a displayable area of the chromaticity points indicated by the positions of the chromaticity points. It may not be displayed correctly.

  As described above, it is difficult for a video signal of a wide color gamut to place the chromaticity point indicated by the information as it is on the coordinate system (scale) in the conventional color gamut. Therefore, in the present embodiment, the information indicated by the wide color gamut video signal is converted by the scale conversion processing described below. By this conversion processing, the displayable area can be converted into a two-dimensional plane similar to the conventional color gamut color system and can be evaluated.

(Scale conversion process)
A conversion process (video signal process) in the scale conversion unit 20 will be described with reference to FIGS. FIG. 5 is a flowchart showing the procedure of the conversion process in the scale conversion unit 20. FIG. 6 is a diagram illustrating a data flow in the conversion process in the scale conversion unit 20 in the case of the “wide color gamut / constant luminance mode”. FIG. 7 is a diagram illustrating a data flow in the conversion process in the scale conversion unit 20 in the case of the “wide color gamut / non-constant luminance mode”.

Returning to FIG. 5, conversion processing (video signal processing) in the scale conversion unit 20 corresponding to the video signal to be processed will be sequentially shown. It is assumed that initialization such as mode setting is performed by the control unit 80 prior to the processing shown in FIG.
First, the procedure in the case of the “wide color gamut / constant luminance mode” in the color system in which the signal format of the video signal is (Yconst ′, C ′ _B , C ′ _R ) will be described. The “wide color gamut / constant luminance mode” in the color system with the video signal format (Yconst ′, C ′ _B , C ′ _R ), the input video signal satisfies the constant luminance principle as shown below. Applicable when transmitted as

The linearization processing unit 21 performs linearization processing (reverse processing) according to the constant luminance principle on the video signal (Yconst′C ′ _B C ′ _R ) (FIG. 6) supplied from the input conversion unit 11 as the input video signal. Gamma processing (see equation (1)) is performed (step Sa210).
Here, an example of specific conversion processing by the linearization processing unit 21 in the calculation processing of step Sa210 will be shown. Each component of the signal format (Yconst ′, C ′ _B , C ′ _R ) of the video signal has a relationship represented by equations (5) and (6) in addition to the above equation (1).

_{C 'B = Bw' - Yconst} '··· (5)
C ′ _R = Rw′−Yconst ′ (6)

  Formula (7) is obtained based on Formula (1) and Formula (5).

_{Bw '(= C' B +} Yconst ') ··· (7)

  Moreover, Formula (8) is obtained based on Formula (1) and Formula (6).

_{Rw '(= C' R +} Yconst ') ··· (8)

Next, Yconst, Bw, and Rw are obtained by performing linearization processing on the equations (1), (7), and (8), respectively. Further, Gw is obtained by adding Yconst, Bw, and Rw to the equation (1) (no prime). Further, hereinafter, it may show Yconst shown in equation (1) as _{Y W.} In short, based on the equations (1), (7), and (8), the linearization processing unit 21 generates a GBR signal (FIG. 6, G _W B _W R _W signal).

The matrix conversion processing unit 22 (first matrix conversion processing unit) generates a “conventional color gamut” from the “wide color gamut” GBR signal (FIG. 6, G _W B _W R _W signal) generated by the linearization processing unit 21. RGB signals to the three primary colors RGB components by color system "(FIG. _{6, R N} G _{N B N} signal) (step SA 220).
Here, an example of specific conversion processing by the matrix conversion processing unit 22 in the calculation processing of step Sa220 is shown. As shown in Expression (9), the matrix conversion processing unit 22 performs matrix calculation processing on RGB signals (Rw, Gw, Bw) of “wide color gamut”, and the three primary colors RGB using the “conventional color gamut” color system. the obtained RGB signals to component (FIG. _{6, R N} G _{N B N} signal). The matrix shown in Equation (9) is obtained from the chromaticities of RGB primary colors and reference white in two color spaces (reference: Hideo Kusaka, “Color Image Engineering” (Ohm)).

The non-linearization processing unit 23 performs non-linearization processing (gamma processing) on the components of the RGB signal (FIG. 6, R _N G _N B _N signal), and R′G′B ′ using the three primary colors RGB as components. A signal (FIG. 6, R _N 'G _N ' B _N 'signal) is generated (step Sa230). Since the color system of the conventional color gamut to match thereto does not satisfy the constant luminance principle, matrix conversion processing unit 24, the R'G'B 'signal (FIG. _{6, R N' G N '} B N' signal) , generates a Y 'and color difference signals Cb' by a color system that does not satisfy the constant luminance principle, Cr 'and is referred to as component Y'Cb'Cr' signal (FIG. 6, _{Y N} 'Cb'Cr' signal) (Step Sa240).

Next, a procedure in the case of the “wide color gamut / non-constant luminance mode” in the color system in which the signal format of the video signal is (Y ′, C ′ _B , C ′ _R ) will be described. As shown below, the “wide color gamut / non-constant luminance mode” in the color system in which the signal format of the video signal is (Y ′, C ′ _B , C ′ _R ) Applicable when transmitted without satisfying.

The linearization processing unit 21 performs linearization processing (in accordance with the non-constant luminance principle) on the video signal (Y′C ′ _B C ′ _R ) (FIG. 7) supplied from the input conversion unit 11 as the input video signal. In order to perform (inverse gamma processing), linearization processing (inverse gamma processing, see equation (2)) is performed for each component. The linearization processing unit 21 generates a GBR signal (FIG. 7) (step Sa210).
Here, an example of a specific conversion procedure by the linearization processing unit 21 in the arithmetic processing of step Sa210 will be shown. Each component of the signal format (Y ′, C ′ _B , C ′ _R ) of the video signal has a relationship represented by equations (10) and (11) in addition to the above equation (2).

C ′ _B = Bw′−Y ′ (10)
C ′ _R = Rw′−Y ′ (11)

  Equation (12) is obtained based on Equation (2) and Equation (10).

Bw '(= C' _B + Y ') (12)

  Moreover, Formula (13) is obtained based on Formula (2) and Formula (11).

_{Rw '(= C' R +} Y ') ··· (13)

  In this way, Bw ′ and Rw ′ are obtained based on the equations (12) and (13). Further, Gw ′ can be obtained by adding Y ′, Bw ′, and Rw ′ to the equation (2). Hereinafter, Y ′ shown in Expression (2) may be indicated as Yw ′. In short, the linearization processing unit 21 generates a Gw′Bw′Rw ′ signal based on the equations (2), (12), and (13).

  The subsequent steps Sa220 to Sa240 are the same as those in the aforementioned “wide color gamut / constant luminance mode”.

  Thus, even if the video signal to be measured is a “wide color gamut” signal, a signal that can be measured based on the same scale as the “conventional color gamut” by the conversion processing in the scale conversion unit 20 shown in FIG. Can be converted to

  Note that, in the “conventional color gamut / non-constant luminance mode”, the conversion processing in the scale conversion unit 20 is not performed. In short, in the case of the “conventional color gamut / non-constant luminance mode”, the vector display screen generation unit 42 receives the video signal (Y′Cb′Cr ′ signal) supplied from the input conversion unit 11 via the video switching unit 30. ) To measure the color. In this case, it is a measurement as “conventional color gamut”, and as described above, it can be measured based on the same scale as in the case of “wide color gamut”.

(Second Embodiment)
The second embodiment differs from the first embodiment in that it is not the color difference signals (C _B ', C _R ') but the primary color signals (B ', R') as the input signal of the wide color gamut video signal. (Luminance signal is the same).
FIG. 8 is a block diagram showing a functional configuration of the vector scope according to the present embodiment. Among the functional configurations shown in FIG. 8, the same reference numerals are given to the same functional configurations as those in FIG. The vector scope 1A shown in FIG. 8 is supplied with a video signal supplied from the outside and a synchronization signal synchronized with the video signal, and measures and displays the color of the supplied video signal. When a signal based on a reference test signal (color bar signal) is supplied as an input video signal to the vector scope 1A, the vector scope 1A displays color information of the color indicated by the measured video signal. Display a screen to measure color reproducibility based on.

The vector scope 1A, like the vector scope 1 (FIG. 1), displays an HDTV system video signal and a video system (such as a UHDTV system) that displays a very high-definition image that greatly exceeds the number of pixels of the display screen displayed by the HDTV system. ) Video signal. When measuring the color indicated by the video signal to be measured, the vector scope 1A determines whether the “conventional color gamut / non-constant luminance mode”, “wide color gamut” is selected according to the type of the video signal supplied from the outside. Switch between the three modes of “Constant Luminance Mode” and “Wide Color Gamut / Non-Constant Luminance Mode”, and measure each video signal.
When the input video signal to be measured in this embodiment is a video signal of an HDTV system, a video signal (Y′Cb′Cr ′) is extracted from the input video signal, and the input video signal to be measured is an ultra high definition image. In the case of a video signal of a video system to be displayed (such as a UHDTV system), the video signal (Yconst'B'R ') or the video signal (Y'B'R') is extracted.

Next, the functional configuration of the vector scope 1A will be described. The vector scope 1A includes an input conversion unit 11A, a reproduction output unit 12, a clock distribution unit 13, a scale conversion unit 20A, a video switching unit 30, a waveform display generation unit 41, a vector display screen generation unit 42, an RGB waveform screen generation unit 43, A status screen generation unit 44, a screen selection synthesis unit 45, a display unit 50, an operation input detection unit 60, and a control unit 80 are provided. The scale conversion unit 20A includes a linearization processing unit 21A, a matrix conversion processing unit 22, a non-linearization processing unit 23, and a matrix conversion processing unit 24.
Unless otherwise specified in the description of FIG. 5, the vector scope 1, the input conversion unit 11, the scale conversion unit 20, and the linearization processing unit 21 in the description of FIG. The scale conversion unit 20A and the linearization processing unit 21A are read respectively.

  When the input video signal is an HDTV system video signal, the input conversion unit 11A sends the extracted video signal (Y′Cb′Cr ′ (first color system)) to the reproduction output unit 12 and the video switching unit 30. Supply. Further, the input conversion unit 11A, when the input video signal is a video signal of a video system (such as a UHDTV system) that displays an ultra-high-definition image, the extracted video signal (Yconst'B'R '(second color specification) System)) or video signal (Y′B′R ′ (second color system)) is supplied to the reproduction output unit 12 and the scale conversion unit 20A. Further, the input conversion unit 11A detects the state of the input video signal that has been input, and supplies the detection result to the control unit 80.

The scale converter 20A converts the video signal supplied from the input converter 11A according to the “wide color gamut / constant luminance mode” or the conversion process according to the “wide color gamut / non-constant luminance mode”. Do either one. The conversion processing in the scale conversion unit 20A is selected according to control by the control unit 80. The scale conversion unit 20A generates a video signal (Y _N 'Cb'Cr') to be supplied to the video switching unit 30 as the “conventional color gamut / non-constant luminance mode” by the selected conversion process. The video signal (Y _N 'Cb'Cr') is expressed by the same color system (first color system) as the video signal (Y'Cb'Cr ').
In other words, the scale converter 20A according to the present embodiment expresses the video signal (input video signal) supplied from the input converter 11 by the first color system (color system corresponding to the conventional color gamut). Converted to a video signal. When the video signal (input video signal) supplied from the input conversion unit 11 is a signal expressed in the second color system (color system corresponding to a wide color gamut), the first color system (conventional) Scale conversion to a video signal expressed in a color system corresponding to the color gamut). In the scale conversion unit 20A, for the first color system and the second color system in which the reference three primary colors of the video signal are different, the chromaticity on the chromaticity diagram corresponding to the reference three primary colors RGB of the first color system. The video signal included in the region on the chromaticity diagram in which the points are formed by chromaticity points corresponding to the reference three primary colors RGB of the second color system is the processing target.

When the input video signal is transmitted while satisfying the constant luminance principle, the linearization processing unit 21A performs linearity corresponding to the constant luminance principle with respect to the video signal (Yconst'B'R ') extracted from the input video signal. Processing (reverse gamma processing), and YBR signal (G _W , first green signal), R (R _W , first red signal) and B (B _W , first blue signal) as components Y _{WB WR W} , the first video signal). Further, when the input video signal is transmitted without satisfying the constant luminance principle, the linearization processing unit 21A performs the non-constant luminance principle on the video signal (Y′B′R ′) extracted from the input video signal. And G (G _W , first green signal), R (R _W , first red signal), and B (B _W , first blue signal) based on the input video signal. GBR signal whose components to produce a _{(G W} B _{W R W,} a first video signal). As described above, the linearization processing unit 21A allows the GBR signal even if the supplied video signal is either the video signal (Yconst'B'R ') or the video signal (Y'B'R'). (G _{WB WR W} , first video signal) is generated. Incidentally, GBR signal generated by the linearization processing section _{21A (G W B W R W} ) is a video signal of wide color gamut.

Next, a case where a wide color gamut video signal is handled as a conventional color gamut video signal will be described.
With reference to FIG. 9, an example of each signal and conversion in this embodiment will be described. FIG. 9 is a diagram showing the relationship between the items indicating the characteristics of the video signal and the values of the variables of the items. The target video signal shown in FIG. 9 is expressed by a signal format including components (Y ′, B ′, R ′). The photoelectric conversion characteristics are determined by a relational expression indicating the relationship between E and E ′. E is a voltage value proportional to the input light intensity detected in each channel of the camera and is a value normalized with reference white. E ′ is a primary color signal obtained by this nonlinear processing. α and β are variables determined according to the number of quantization bits. For example, when the quantization bit number is 10 bits, α = 1.0099 and β = 0.018, and when the quantization bit number is 12 bits, α = 1.993 and β = 0.0181. Good.

  Next, a signal equation of the luminance signal is shown. The signal equation shown in this figure is for the case of transmission satisfying the constant luminance principle. Equation (14) shows a signal equation of a luminance signal when transmitted while satisfying the constant luminance principle.

Yconst '= (rR + gG + bB)' (14)

  In Expression (14), Yconst ′ represents a luminance value when transmission is performed while satisfying the constant luminance principle. “′ (Prime)” indicates the result of the non-linear processing (gamma correction processing). R, G, and B respectively indicate the components of the three primary colors RGB of the video signal having a wide color gamut. “r”, “g”, and “b” indicate coefficients to be respectively multiplied by the components of the three primary colors RGB of the wide color gamut video signal. As shown in this equation (14), Yconst ′ is a non-linearization process (gamma correction process) that is obtained by adding a product obtained by multiplying each component of the three primary colors RGB of the video signal having a wide color gamut by a coefficient. ) To get.

  On the other hand, the signal equation of the luminance signal when transmitted without satisfying the constant luminance principle is shown in Equation (15).

Y ′ = rR ′ + gG ′ + bB ′ (15)

  In Equation (15), Y ′ represents a luminance value when transmitted without satisfying the constant luminance principle. As shown in this equation (15), Y ′ is a non-linear process (gamma correction process) for each of the three primary colors RGB of the video signal having a wide color gamut, and a coefficient is added to the result. It is obtained by adding the products multiplied by each.

As described above, the luminance signal signal equations shown in the equations (14) and (15) each include nonlinear processing. Therefore, a calculation error due to the difference in the calculation method of the nonlinear processing described above may occur between the Yconst ′ value and the Y ′ value calculated by the expressions (14) and (15).
Note that the quantization characteristics of the luminance signal and the color difference signal and the quantization characteristics of the primary color signal in this embodiment may be determined according to the standard of the HDTV system, for example.

  Also in the present embodiment, the displayable area can be converted into a two-dimensional plane having the same scale as that of the color system of the conventional color gamut and evaluated by the scale conversion process described below.

(Scale conversion process)
A procedure of conversion processing (video signal processing) in the scale conversion unit 20A will be described. The procedure of the conversion process in the scale converter 20A is the same as the procedure of the conversion process in the scale converter 20 described above. The flowchart showing the procedure of the conversion process in the scale conversion unit 20A is not shown, and the flowchart shown in FIG. 5 is referred to.

In addition, with reference to FIGS. 10 and 11, conversion processing (video signal processing) in the scale conversion unit 20 </ b> A according to the video signal to be processed will be sequentially shown.
First, the case of the “wide color gamut / constant luminance mode” in the color system in which the signal format of the video signal is (Yconst ′, B ′, R ′) will be described.
FIG. 10 is a diagram illustrating a data flow in the conversion processing in the scale conversion unit 20A in the case of the “wide color gamut / constant luminance mode”. The “wide color gamut / constant luminance mode” in the color system with the video signal format (Yconst ′, B ′, R ′), the input video signal satisfies the constant luminance principle and is transmitted as shown below. Applies when The linearization processing unit 21A performs linearization processing (inverse gamma processing, equation (14) according to the constant luminance principle on the video signal (Yconst'B'R ') supplied from the input conversion unit 11A as the input video signal. )) To generate a GBR signal (G _W B _W R _W signal). The process of generating the GBR signal (G _W B _W R _W signal) by the linearization processing unit 21A corresponds to step Sa210 in FIG. The conversion process from GBR signal _{(G W} B _{W R W} signal) until generating a Y'Cb'Cr 'signal _{(Y N'} Cb'Cr 'signal), the conversion process shown in FIG. 5 (Step Sa220 To Sa240).

Next, the procedure of the “wide color gamut / non-constant luminance mode” in the color system in which the signal format of the video signal is (Y ′, B ′, R ′) will be described.
FIG. 11 is a diagram illustrating a data flow in the conversion processing in the scale conversion unit 20A in the case of the “wide color gamut / non-constant luminance mode”. In the “wide color gamut / non-constant luminance mode” in the color system in which the signal format of the video signal is (Y ′, B ′, R ′), the input video signal does not satisfy the constant luminance principle as shown below. Applicable when transmitted to. The linearization processing unit 21A performs linearization processing (inverse gamma processing) according to the non-constant luminance principle on the video signal (Y′B′R ′) supplied from the input conversion unit 11A as the input video signal. The video signal (GBR) is supplied to the matrix conversion processing unit 22 as the generated signal. The process of generating the GBR signal (G _W B _W R _W signal) by the linearization processing unit 21A corresponds to step Sa210 in FIG.

The conversion process from GBR signal _{(G W} B _{W R W} signal) until generating a Y'Cb'Cr 'signal _{(Y N'} Cb'Cr 'signal), the conversion process shown in FIG. 5 (Step Sa220 To Sa240).

  As described above, even if the video signal to be measured is a “wide color gamut” signal, the scale conversion unit 20A converts the video signal to a signal that can be measured based on the same scale as the “conventional color gamut”. Can do.

According to the embodiment described above, the scale converter 20 (20A) of the vector scope 1 (1A) (video signal processing apparatus) has the first color system (with the conventional color gamut) in which the reference three primary colors of the video signal are different. Chromaticity points on the chromaticity diagram corresponding to the reference three primary colors RGB of the first color system are the first color system and the second color system (color system corresponding to a wide color gamut). The video signal included in the region on the chromaticity diagram formed by the chromaticity points corresponding to the reference three primary colors RGB of the color system 2 is processed. When the input video signal is a signal expressed in the second color system (color system corresponding to a wide color gamut), the scale conversion unit conversion unit 20 (20A) performs the first color system ( Scale conversion to a video signal expressed in a color system according to the conventional color gamut).
Thereby, the vector scope 1 (1A) converts the input video signal expressed by the second color system (color system corresponding to the wide color gamut) to the first color specification by the scale converter 20 (20A). It can be converted into a video signal (fourth video signal) expressed by a system (color system corresponding to a conventional color gamut).
Here, the first color system is, for example, a color system that can represent a conventional color gamut, and the second color system is, for example, a color that is widened from the conventional color gamut. It is a color system that can express a range. The reference primary colors include three primary colors (RGB) and reference white.

Note that the scale converter 20 (20A) applies the input video signal to the input video signal in which the color gamut in the color system of the video signal is a second color gamut that is widened from the first color gamut. In addition to the linearization process corresponding to the first color signal, the coordinate conversion process for converting the color gamut of the input video signal subjected to the linearization process makes the first color system signal from the second color gamut (wide color gamut) signal. A color system signal of the color gamut (conventional color gamut) may be generated.
Thereby, the vector scope 1 (1A) performs linearization processing corresponding to the input video signal on the input video signal that is the second color gamut by the scale conversion unit 20 (20A). In addition, the scale conversion unit 20 (20A) performs the conversion from the color system signal of the second color gamut (wide color gamut) by coordinate conversion processing that converts the color gamut to the input video signal that has been linearized. A color system signal of one color gamut (conventional color gamut) can be generated.

In such a scale conversion unit 20 (20A), when the input video signal is transmitted while satisfying the constant luminance principle, the linearization processing unit 21 performs linearization processing on the input video signal according to the constant luminance principle. Since the first video signal having the three primary colors RGB (first green signal, first red signal, and first blue signal) as components is generated, the linearity of the input video signal transmitted satisfying the constant luminance principle is generated. It is possible to generate a first video signal that has been processed.
Further, when the color gamut in the color system of the input video signal is the second color gamut widened from the first color gamut, the matrix conversion processing unit 22 receives the first video signal from the first video gamut. Since the second video signal having the three primary colors RGB in the color gamut color system as a component is generated, the color gamut of the second video signal can be converted from the second color gamut to the first color gamut. it can. In short, the matrix conversion processing unit 22 changes the reference three primary colors of the first video signal generated by the linearization processing unit 21 from the reference three primary colors RGB of the second color system to the reference of the first color system. In addition to conversion to the three primary colors RGB, conversion to a second video signal having the three primary colors RGB as components.
Further, the non-linearization processing unit 23 performs non-linear processing on each component of the second video signal to generate a third video signal having the three primary colors RGB as components. Then, the matrix conversion processing unit 24 generates, from the third video signal, a fourth video signal whose components are the second luminance signal and the color difference signal based on the color system that does not satisfy the constant luminance principle. In short, the matrix conversion processing unit 24 uses the first color system based on the first color system that does not satisfy the constant luminance principle as the reference three primary colors RGB of the first color system based on the third video signal. A fourth video signal having the above components as a component is generated.
Thereby, the vector scope 1 (1A) can measure the color indicated by the input video signal based on the fourth video signal.

  Further, even a video system applied to a standardized HDTV with a wide color gamut may handle video signals of programs that do not place importance on color reproducibility. When handling video signals of such programs, even if the video signal handled by the video system is a wide color gamut format signal, the color gamut indicated by the actual video signal is the same color gamut as the conventional color gamut. It is assumed that it can be expressed. In such a case, rather than using a measurement system that supports a wide color gamut to detect using a scale based on the conventional color gamut, use a vector scope whose color system is the conventional color gamut to get used to the vector scope. It is easier for users who are present.

  According to the vector scope 1 shown in the present embodiment, the color gamut used as a reference (conventional color gamut) also in the measurement of the color (color reproducibility in the video signal) indicated by the video signal having a wide color gamut. It is possible to measure according to the same coordinate system (scale) as the coordinate system (scale) of the color space of the video signal.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes changes and the like without departing from the gist of the present invention. For example, the scale converter 20 (20A) may be divided into a plurality of parts. The division method can use the components in the scale conversion unit 20 as a unit. Or you may divide | segment according to the area | region of a display screen. Further, the arithmetic processing in the scale conversion unit 20 may refer to a lookup table (LUT) in which information calculated in advance is stored.

The vector scope 1 is transmitted as a “wide color gamut” signal without satisfying the constant luminance transmission and the video signal (Yconst′C ′ _B C ′ _R ) transmitted satisfying the constant luminance transmission. The video signal (Y′C ′ _B C ′ _R ) has been described as an input video signal. Alternatively, as in the case of the vector scope 1A, in addition to the above signal format, as a “wide color gamut” signal, a video signal (Yconst′B′R ′) transmitted satisfying constant luminance transmission and a constant luminance Any of the video signals (Y′B′R ′) transmitted without satisfying the transmission may be used as the input video signal.

The vector scope 1 (1A) has been described as including the scale conversion unit 20 (20A). However, the function of the scale conversion unit 20 (20A) is used as a video signal processing device outside the vector scope 1 (1A). It may be configured.
Further, such a video signal processing device may perform a signal conversion process for generating a video signal to be provided to other devices constituting the video system.
In addition, a device constituting the video system, which is a video signal processing device, may have the function of the scale conversion unit 20. With such a video signal processing apparatus, for example, a down converter from a high-definition image signal with a wide color gamut can be easily configured.

  The vector scope 1 described above has a computer system inside. The operation process of each functional unit is stored in a computer-readable recording medium in the form of a program, and the above processing is performed by the computer system reading and executing the program. The computer system here includes a CPU, various memories, an OS, and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

1, 1A ... Vector scope (video signal processing device),
20, 20A ... scale converter 21, 21A ... linear converter,
22: Matrix conversion processing unit,
23: Nonlinear conversion unit,
24 ... Matrix conversion processing unit,
42. Vector display screen generation unit

Claims (4)

For the first color system and the second color system in which the reference three primary colors of the video signal are different, the chromaticity point on the chromaticity diagram corresponding to the reference three primary colors RGB of the first color system is the first color system. 2 included in the region on the chromaticity diagram formed by chromaticity points corresponding to the reference three primary colors RGB of the color system 2;
A scale conversion unit that performs scale conversion to a video signal expressed in the first color system when an input video signal is a signal expressed in the second color system;
The scale converter is
A linearization processing unit that linearizes the input video signal to generate a first video signal;
The reference three primary colors of the generated first video signal are converted from the reference three primary colors RGB of the second color system to the reference three primary colors RGB of the first color system, and the three primary colors RGB are components. A first matrix conversion processing unit for converting into two video signals;
A non-linearization processing unit that generates a third video signal having components of three primary colors RGB by performing a non-linear process on each component of the second video signal;
The third video signal includes, as components, a luminance signal and a color difference signal of the first color system that does not satisfy the constant luminance principle, and uses the reference three primary colors RGB of the first color system as the reference three primary colors. A second matrix conversion processing unit for generating four video signals;
It further comprising a Film image signal processing apparatus. The linearization processing unit includes:
When the input video signal is transmitted satisfying the constant luminance principle, the input video signal is linearized according to the constant luminance principle,
When the input video signal is transmitted without satisfying the constant luminance principle, the input video signal is linearized according to the non-constant luminance principle, and the three primary colors RGB based on the input video signal are used as components. Generate a first video signal
The video signal processing apparatus according to claim 1 . The video signal processing device according to claim 1 or 2 ,
In a two-dimensional coordinate plane in which orthogonal coordinate axes are shown, a display screen showing the two components of the color difference signal as corresponding to the orthogonal coordinate axes and indicating the position of a point on the two-dimensional coordinate plane from the two component values of the color difference signal A vector display generating unit for generating
A vectorscope characterized by comprising: Computer
The program for functioning as a video signal processing apparatus of Claim 1 or 2.