JP2009159511A - Generation system of signal conversion table, generation method of signal conversion table, and generation program of signal conversion table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a generation system of a signal conversion table, a generation method of the signal conversion table, and a generation program of the signal conversion table for generating a signal conversion table for use in adjustment of picture quality so that tone of the picture quality approximates tone of target picture quality. <P>SOLUTION: A control part of a picture quality adjusting device measures input/output characteristics of a reference video display device 20 and an adjustment target video display device 10. When a region (a reference output signal space) defined by a reference output signal value is not included in a region defined by a value of a signal to be adjusted, the control part sets a virtual input signal obtained by expanding the input signal and calculates a virtual output signal corresponding to the virtual input signal. When the reference output signal space is not included in a region (a virtual output signal space) defined by a value of the virtual output signal, the control part resets the virtual input signal until the reference output signal space is included. When the reference output signal space is included in the virtual output signal space, the control part calculates a tentative LUT, clips a space expanded in the tentative LUT to generates a LUT. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a signal conversion table generation system, a signal conversion table generation method, and a signal conversion table used to convert a signal so that the image quality of a video display device such as a display is close to the target image display device. It relates to the generation program.

  In a video display device such as a display, it is desired to display a high-quality video. Therefore, some video display apparatuses are provided with an image quality adjustment engine for adjusting the image quality. For example, some television receivers equipped with a liquid crystal module adjust white balance efficiently and inexpensively (see, for example, Patent Document 1). In the technique described in this document, an R (red), G (green), or B (blue) adjustment coefficient is input, and the gamma table is rewritten based on the adjustment coefficient. When the adjustment operator determines that the chromaticity of the pattern image on the liquid crystal module has reached the target chromaticity, the adjustment coefficient is stored as an adjustment confirmation value. Then, an adjustment gamma table is created by reflecting the adjustment confirmation value in the gamma table.

In addition, the inventors of the present invention have also studied a technique for automatically approximating a target image quality device (reference image display device) with an image quality of an adjustment target device (adjustment target image display device) (Japanese Patent Application). (See 2007-029629). In this case, the signal processing circuit that performs signal conversion is adjusted so that the output signal (adjustment target output signal) of the adjustment target video display device relative to the input signal is the same as the output signal (reference output signal) of the reference video display device Provided in the target video display device. This signal processing circuit stores a signal conversion table for signal conversion. This signal conversion table is created from the relationship between the input signal of the adjustment target video display device and the input signal of the reference video display device when the adjustment target output signal and the reference output signal are matched.
JP 2006-325014 A (first page)

  By the way, when the image (video) that can be expressed by the adjustment target video display device is different from the image (video) that can be expressed by the reference video display device, the adjustment target output signal may not match the reference output signal. Conventionally, an adjustment target output signal that approximates the output signal of the video display device is specified for this portion, and an input signal corresponding to this is specified, and a signal conversion table is created. When the image of the adjustment target image display device is adjusted using the signal conversion table created in this way, the color tone of the image quality is different. In particular, when the signal conversion table is set roughly, the color tone of the image quality is greatly different, and it is difficult to approximate the image quality of the reference video display device.

  The present invention has been made in view of the above-described problems, and an object thereof is a signal conversion table generation system and a signal conversion table generation method for generating a signal conversion table for adjustment so as to be approximated by a tone of a target image quality. And providing a signal conversion table generation program.

In order to solve the above problems, the invention according to claim 1 is characterized in that an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table is Stored adjustment target characteristic storage means, reference characteristic storage means for storing reference input / output characteristics of a reference output signal with respect to an input signal input to an image quality target reference video display device, and control means for generating the signal conversion table The control means includes a reference output signal space in which the reference input / output characteristics are expressed by output signal coordinates, and an adjustment target output signal space in which the adjustment target input / output characteristics are expressed by output signal coordinates. And when the reference output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by extending the input signal is set, and this Virtual output calculation means for calculating a virtual output signal when a virtual input signal is input to the adjustment target video display device using adjustment target input / output characteristics stored in the adjustment target characteristic storage means; and the virtual output signal Means for calculating a temporary signal conversion table using the virtual input / output characteristics and the reference input / output characteristics stored in the reference characteristic storage means, and the input signal of the temporary signal conversion table is the virtual input signal The gist of the invention is that it includes a limiting means for calculating the signal conversion table by limiting the input signal to a range that the original input signal can take.

  According to a second aspect of the present invention, in the signal conversion table generating system according to the first aspect, the control means inputs an input signal changed at a predetermined interval to the reference video display device, Reference output signal measuring means for acquiring a corresponding reference output signal, and adjustment for inputting an input signal changed at the predetermined interval to the adjustment target video display device and acquiring an adjustment target output signal corresponding to the input signal A setting process for setting the virtual input signal expanded at the predetermined interval with respect to the input signal when it is determined that the reference output signal space is not included. A virtual space comparison process for comparing a virtual output signal space expressing virtual input / output characteristics of the set virtual input signal with output signal coordinates and the reference output signal space. And when the reference output signal space is not included in the virtual output signal space, the setting process and the virtual space comparison process are repeated so that the reference output signal space is the virtual output And a means for calculating a virtual output signal corresponding to the virtual input signal set when included in the signal space.

  According to a third aspect of the present invention, in the signal conversion table generating system according to the first or second aspect, the input signal is a component-type video signal composed of three elements, and the limiting means includes When each element of the virtual input signal of the temporary signal conversion table is smaller than the range that the input signal can originally take, the input signal is limited to the minimum value of the range that the input signal can take originally, and when the input signal is larger than the range that can be taken originally The gist of the present invention is to limit the input signal to the maximum value that can be originally taken.

  According to a fourth aspect of the present invention, there is provided an adjustment target characteristic storage means for storing an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table. A method for generating the signal conversion table by using a reference characteristic storage unit storing a reference input / output characteristic of a reference output signal with respect to an input signal input to an image quality target reference video display device, and a control unit. The control means compares the reference output signal space expressing the reference input / output characteristics with output signal coordinates and the adjustment target output signal space expressing the adjustment target input / output characteristics with output signal coordinates; When a reference output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by extending the input signal is set, and the virtual input signal is set as the adjustment target video. A virtual output calculation step of calculating a virtual output signal when input to the display device using an adjustment target input / output characteristic stored in the adjustment target characteristic storage means; a virtual input / output characteristic of the virtual output signal; and The step of calculating the temporary signal conversion table using the reference input / output characteristics stored in the reference characteristic storage means, and when the input signal of the temporary signal conversion table is the virtual input signal, the original input signal is The gist of the present invention is to perform a limiting step of calculating the signal conversion table by limiting to an input signal in a possible range.

According to a fifth aspect of the present invention, there is provided an adjustment target characteristic storage means for storing an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table. A program for generating the signal conversion table using a reference characteristic storage unit storing a reference input / output characteristic of a reference output signal with respect to an input signal input to an image quality target reference video display device, and a control unit. The control means for comparing the reference output signal space in which the reference input / output characteristic is expressed in output signal coordinates with the adjustment target output signal space in which the adjustment target input / output characteristics are expressed in output signal coordinates, the reference When the output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by extending the input signal is set, and the virtual input signal is set as the adjustment target. Virtual output calculation means for calculating a virtual output signal when input to an image display device using an adjustment target input / output characteristic stored in the adjustment target characteristic storage means, a virtual input / output characteristic of the virtual output signal, and The means for calculating the temporary signal conversion table using the reference input / output characteristics stored in the reference characteristic storage means, and when the input signal of the temporary signal conversion table is the virtual input signal, the original input signal is The gist is to limit the input signal to a range that can be taken and to function as a limiting means for calculating the signal conversion table.

(Function)
According to the first, fourth, or fifth aspect of the invention, when the reference output signal space is not included in the adjustment target output signal space, the control unit sets a virtual input signal obtained by extending the input signal, and the virtual input signal Is output to the adjustment target video display device using the input / output characteristics of the adjustment target video display device. The control means calculates the temporary signal conversion table using the input / output characteristics of the virtual output signal and the input / output characteristics of the reference video display device. When the input signal of the temporary signal conversion table is a virtual input signal, the control means limits the input signal to a range that the original input signal can take and calculates the signal conversion table. For this reason, the signal conversion table specifies a virtual input signal corresponding to the virtual output signal from the virtual output signal that matches the reference output signal, and approximates the virtual input signal to a range that the original input signal can take. Generated. Since the reference output signal space and the adjustment target output signal space are nonlinear in shape, the input signal of the adjustment target video display device is specified from the adjustment target output signal approximated to the reference output signal, and this input signal is used. When the signal conversion table is generated, the video of the adjustment target video display device has a different color tone. Compared to this case, since the virtual input signal corresponding to the virtual output signal that matches the reference output signal is used, the difference in color tone can be reduced. Therefore, an image whose color tone is more similar to the image of the reference image device can be realized by the adjustment target image display device.

  According to the second aspect of the present invention, the control means inputs the input signal changed at a predetermined interval to the reference video display device, and acquires the reference output signal corresponding to the input signal. The control means inputs the input signal changed at a predetermined interval to the adjustment target video display device, and acquires the adjustment target output signal corresponding to the input signal. The control means executes a setting process for setting the virtual input signal expanded for the predetermined interval with respect to the input signal when it is determined that the reference output signal space is not included. The control means executes a virtual space comparison process for comparing a virtual output signal space representing the virtual output signal corresponding to the set virtual input signal in a three-dimensional matrix with a reference output signal space. When the reference output signal space is not included in the virtual output signal space, the control unit repeats the setting process and the virtual space comparison process, and when the reference output signal space is included in the virtual output signal space. A virtual output signal corresponding to the set virtual input signal is calculated. That is, the control means sets a virtual input signal expanded by a predetermined interval, and determines whether or not the reference output signal space is included in the corresponding virtual output space. When the virtual output space including the reference output signal space can be identified, a temporary signal conversion table is generated using the virtual input / output characteristics of the virtual output signal. Therefore, the number of virtual input / output characteristic data used for creating the temporary signal conversion table can be reduced, and the signal conversion table can be generated efficiently.

According to the third aspect of the present invention, when each element of the input signal of the temporary signal conversion table is smaller than the range that the input signal can originally take, the control means can minimize the range that the input signal can take originally. When the input signal is larger than the range that can be originally taken, the input signal is limited to the maximum value of the range that can be taken. Therefore, it is possible to generate a signal conversion table using input signals in a range that can be originally taken.

  According to the present invention, it is possible to realize an image of a color tone that is more similar to the image of the reference image device with the adjustment target image display device.

  Hereinafter, an embodiment of a signal conversion table generating apparatus embodying the present invention will be described with reference to FIGS. The signal conversion table is a table used for converting the input signal so that the image quality of the adjustment target video display device approximates the image quality of the reference video display device. In this embodiment, a liquid crystal display (LCD) is used as the adjustment target video display device and the reference video display device.

First, the configuration of the adjustment target video display device will be described with reference to FIG.
As shown in FIG. 1A, the adjustment target video display device 10 includes a video processing circuit 12, a look-up table (hereinafter referred to as LUT) conversion circuit 15, and a video display device 16. The input video signal of the adjustment target video display device 10 is supplied to the video processing circuit 12. Normally, a luminance color difference signal (YPbPr signal) is used as an input signal, but an RGB input video signal (RGB signal) is used to simplify the description. Note that the RGB signal and the luminance color difference signal can be converted and inversely converted by a linear matrix operation.

  The video processing circuit 12 performs video signal processing such as noise removal processing and synchronization signal separation processing. The video processing circuit 12 supplies the corrected RGB signal (R ′, G ′, B ′ in FIG. 1A) subjected to the video signal processing to the LUT conversion circuit 15.

  The LUT conversion circuit 15 stores an LUT as signal conversion data such as a signal conversion table. The LUT conversion circuit 15 converts the input corrected RGB signals (R ′, G ′, B ′) into converted RGB signals (R ″, G ″, B ″) using the stored LUT, and displays the video. This is supplied to the display device 16.

The video display device 16 (LCD panel in the present embodiment) outputs (displays) a color image corresponding to the converted RGB signal (R ″, G ″, B ″) supplied from the LUT conversion circuit 15. Is evaluated using the chromaticity (x, y) and luminance (Lv), and this is used as an output signal (adjustment target output signal) of the adjustment target video display device 10. Therefore, the video display device 16 The adjustment target output signal (x, y, Lv) is output in accordance with the converted RGB signal (R ″, G ″, B ″).

Next, the configuration of the reference video display device that is the target of the image quality expressed by the adjustment target video display device will be described with reference to FIG.
As shown in FIG. 1B, the reference video display device 20 includes a video processing circuit 22 and a video display device 26. The same input video signal as that of the adjustment target video display device 10 described above is also input to the reference video display device 20.

  The input video signal is input to the video processing circuit 22 of the reference video display device 20, and video signal processing such as input video signal noise removal processing and synchronization signal separation processing is performed in the same manner as the video processing circuit 12. The video processing circuit 22 supplies the corrected RGB signal (Rr, Gr, Br in FIG. 1B) subjected to the video signal processing to the video display device 26.

The video display device 26 (LCD panel in the present embodiment) performs color development according to the input corrected RGB signals (Rr, Gr, Br). The color from the video display device 26 becomes the output of the reference video display device 20. Color development from the video display device 26 is evaluated using chromaticity (x ′, y ′) and luminance (Lv ′), and this is used as an output signal (reference output signal) of the reference video display device 20. Therefore, the video display device 26 outputs the reference output signal (x ′, y ′, Lv ′) according to the input corrected RGB signal (Rr, Gr, Br).

Next, a measuring apparatus for measuring the input / output characteristics of the adjustment target video display device 10 and the reference video display device 20 described above in the present embodiment will be described with reference to FIG.
The measurement apparatus in the present embodiment includes an image quality adjustment device 30 and a display analyzer 40.

  The image quality adjustment device 30 includes a control unit 31 and a data storage unit 32 as control means. The control unit 31 of the image quality adjustment device 30 includes a CPU, a RAM, a ROM, and the like (not shown), and includes processes described later (a process including a reference output signal measurement stage, an adjustment target output signal measurement stage, a virtual output calculation stage, a restriction stage, etc. ). By executing the LUT creation processing program for that purpose, the control unit 31 functions as a reference output signal measuring unit, an adjustment target output signal measuring unit, a virtual output calculating unit, a limiting unit, and the like. The control unit 31 generates a test video signal and supplies it to the video display device (the adjustment target video display device 10 or the reference video display device 20). The control unit 31 acquires the chromaticity and luminance output signals acquired by the display analyzer 40 in accordance with the supply timing of the test video signal (synchronized), and the relation data (input data) of the input signal and the output signal. Output characteristic data).

  The data storage unit 32 functions as an adjustment target characteristic storage unit, a reference characteristic storage unit, and an LUT storage unit. The data storage unit 32 is divided into an adjustment target characteristic data area, a reference characteristic data area, a virtual characteristic data area, and an LUT data area. In the adjustment target characteristic data area of the data storage unit 32, input / output characteristic data (adjustment target input / output characteristic data) of the adjustment target video display device 10 is stored. In the reference characteristic data area of the data storage unit 32, input / output characteristic data (reference input / output characteristic data) of the reference video display device 20 is stored. In the virtual characteristic data area of the data storage unit 32, virtual input / output characteristic data of a virtual output signal with respect to a virtual input signal is stored. In the LUT data area of the data storage unit 32, an LUT created as described later is stored.

  The display analyzer 40 is a measuring instrument that measures the color development state (output) of the video display device (16, 26). In the present embodiment, a color luminance meter that measures luminance and chromaticity is used as the display analyzer 40. The display analyzer 40 supplies the measured chromaticity and luminance to the image quality adjustment device 30.

Next, a method of creating an LUT held by the LUT conversion circuit 15 of the adjustment target video display device 10 described above will be described.
(Outline of LUT creation method)
First, an outline of an LUT creation method will be described.

Here, the video signal processing is performed in the video processing circuits (12, 22), but the input video signals (R, G, B) that have been input are output so that there is no change in characteristics at static signal levels. Assume that In this case, in the adjustment target video display device 10, the corrected RGB signal (R ′, G ′, B ′) input to the LUT conversion circuit 15 is equal to the input video signal (R, G, B). In the reference video display device 20, the corrected RGB signals (Rr, Gr, Br) input to the video display device 26 are equal to the input video signals (R, G, B).

In the present embodiment, the adjustment target output signal (x, y, Lv) when the input video signal is input to the adjustment target video display device 10 and the reference output signal in the reference video display device 20 to which the input video signal is input. The LUT is created by matching (x ′, y ′, Lv ′).

Therefore, first, reference output signals (x ′, y ′, Lv ′) when the input video signals (R, G, B) of the reference video display device 20 are input are obtained using the reference input / output characteristic data. . The input signal (r, g, b) corresponding to the adjustment target output signal (x, y, Lv) that matches the reference output signal (x ′, y ′, Lv ′) is used as the adjustment target input / output characteristic data. Ask.

Here, the possible range of the reference output signals (x ′, y ′, Lv ′) of the reference video display device 20 is as follows.
When it is wider than the range of the adjustment target output signal (x, y, Lv) of the adjustment target video display device 10, the adjustment target output signal (x, y, Lv ') that matches the reference output signal (x', y ', Lv') y, Lv) does not exist. In this case, the present invention assumes a virtual input signal in which the input video signals (R, G, B) of the adjustment target video display device 10 are virtually expanded (extended in the plus direction and the minus direction). A virtual output signal (x, y, Lv) corresponding to the input signal is obtained. The virtual input signal is set so that the virtual output signal (x, y, Lv) is wider than the reference output signal (x ′, y ′, Lv ′).

Then, the temporary input signal (r ′, g ′, b ′) corresponding to the virtual output signal (x, y, Lv) that matches the reference output signal (x ′, y ′, Lv ′) is converted into the virtual output signal ( x, y, Lv) is specified using virtual input / output characteristic data. The specified temporary input signal (r ′, g ′, b ′) and the input video signal (R, G, B) input to the reference output signal (x ′, y ′, Lv ′) are related to each other temporarily. Find the LUT of In this temporary LUT, the temporary input signals (r ′, g ′, b ′) are input video signals (R, G, B).
If it is a value outside the range that can be originally taken, perform clipping processing to limit the value of the temporary input signal (r ′, g ′, b ′) so that it becomes the value in the original range, Create an LUT from the temporary LUT.

Next, LUT creation processing that specifically realizes such an outline will be described with reference to FIG.
(LUT creation process)
First, the control unit 31 of the image quality adjustment device 30 executes an input / output characteristic measurement process of the reference video display device 20 (step S1-1). Here, the reference image display device 20 is connected to the measurement apparatus shown in FIG. Then, the control unit 31 sets the input video signal (R, G, B) for each predetermined interval at an intensity from “0” to “255” (in “256” step intensity that can be expressed by 8 bits). In the embodiment, the reference output signal (x ′, y ′, Lv ′) corresponding to the reference output signal (x ′, yv, Lv ′) is acquired. Then, the control unit 31 of the image quality adjusting device 30 calculates the reference input / output characteristics from the values of the input video signals (R, G, B) and the corresponding reference output signals (x ′, y ′, Lv ′). Data [x ′ (R, G, B), y ′ (R, G, B), Lv ′ (R, G, B)] is generated and stored in the reference characteristic data area of the data storage unit 32.

This reference input / output characteristic data [x ′ (R, G, B), y ′ (R, G, B), Lv ′ (R, G, B)] is represented by 3 as shown in FIG. It can be expressed using a dimensional matrix space. For this reason, in the reference characteristic data area, the reference output signal (x ′, y ′, Lv) corresponds to the value of the input video signal (R, G, B).
') Is stored. For example, “x ′ (0,0,0)” indicates the value of the element “x ′” of the video output for the input video signal (R = 0, G = 0, B = 0). Furthermore, for each coordinate (for example, (0,0,0)), each value (x ′ (0,0,0), y ′ () of the reference output signal (x ′, y ′, Lv ′) 0,0,0) and Lv ′ (value of 0,0,0) are stored in association with each other.

Next, the control unit 31 of the image quality adjustment device 30 executes the input / output characteristic measurement process of the adjustment target video display device 10 (step S1-2). Here, the adjustment target video display device 10 is connected to the measurement device. In this case, the LUT conversion circuit 15 performs the same conversion RGB signal (R ″, G ″, B ″) as the input corrected RGB signal (R ′, G ′, B ′) without performing signal conversion. Set to output.

Then, the control unit 31 of the image quality adjustment device 30 changes the input video signal (R, G, B) from “0” to “256” (in the same manner as the input / output characteristic measurement processing of the reference video display device 20 described above). Actually, it is changed at predetermined intervals (every “32”) with an intensity of up to 255), and the corresponding adjustment target output signal (x, y, Lv) is acquired. Then, the control unit 31 of the image quality adjustment device 30.
Is the value of the adjustment target output signal (x, y, Lv) corresponding to the input video signal (R, G, B),
The adjustment target input / output characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B)] is generated and stored in the adjustment target characteristic data area of the data storage unit 32. Remember. This adjustment target input / output characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B)] can be expressed in a three-dimensional matrix space, and the input video signal Corresponding to the value of (R, G, B), the value of the adjustment target output signal (x, y, Lv) is stored.

Next, the control unit 31 of the image quality adjustment device 30 determines whether or not the reference output signal space is included in the adjustment target output signal (step S1-3). Here, first, the control unit 31 of the image quality adjustment apparatus 30 converts the input / output characteristic data of RGB coordinates from the input signal coordinate system to the output signal coordinate system. Specifically, the control unit 31 refers to reference input / output characteristic data [x ′ (R, G, B), y ′ (R, G, B), Lv expressed in the RGB coordinate system of the reference video display device 20. '(R, G, B)] is converted into a reference output signal (x', y ', Lv') coordinate system as shown in FIG. 4 (b). Note that the region (reference output signal space) determined by the values of the reference output signals (x ′, y ′, Lv ′) in FIG. 4B is expressed by a simple shape having linearity for easy explanation. However, it is actually non-linear and the shape is complicated.

Similarly, the control unit 31 adjusts input / output characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B) expressed in the RGB coordinate system. ] Is converted into an adjustment target output signal (x, y, Lv) coordinate system.
The region (adjustment target output space) determined by the value of the adjustment target output signal (x, y, Lv) converted into the adjustment target output signal (x, y, Lv) coordinate system is actually nonlinear. The shape is also complicated.

The control unit 31 then outputs the reference output signal (x ′, y ′, Lv ′) and the adjustment target output signal (x, y,
Lv) is expressed in the same coordinate system (coordinate space), and the adjustment target output space and the reference output signal space are compared.

Here, when the reference output signal space is included in the adjustment target output space (in the case of “YES” in step S1-3), the control unit 31 of the image quality adjustment device 30 executes the LUT generation processing. (Step S1-4). Specifically, the control unit 31 refers to the reference input / output characteristic data [x ′ (R, G, B), y ′ (R, G, B), Lv ′ (R, G, B)] and the adjustment target. I / O characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B)]
x ′ (R, G, B) = x (r, g, b) (1)
y ′ (R, G, B) = y (r, g, b) (2)
Lv ′ (R, G, B) = Lv (r, g, b) (3)
An input signal (r, g, b) that satisfies is calculated. The control unit 31 associates the input video signal (R, G, B) and the input signal (r, g, b) with each coordinate of the three-dimensional matrix, and stores it in the LUT data area of the data storage unit 32. Store. In this case, for example,
R ″ (R, G, B) = r (4)
G ″ (R, G, B) = g (5)
B ″ (R, G, B) = b (6)
Is stored as follows. As a result, an LUT for converting the input video signal (R, G, B) into the input signal (r, g, b) is generated.

  On the other hand, when the reference output signal space is not included in the adjustment target output signal space (in the case of “NO” in step S1-3), the control unit 31 of the image quality adjustment device 30 performs virtual input by extending the input signal. A signal setting process is executed (step S1-5). Specifically, the control unit 31 generates a virtual input signal (R +, G +, B +) obtained by extending the input signal range by a predetermined interval. In the present embodiment, a value of “32” is set as the predetermined interval. For example, when the range that each element (R, G, or B) can take when the control unit 31 determines that the reference output signal space is not included is “0 to 255”, FIG. As shown, a virtual input signal in the range of “−32 to 287” is generated by extending this range by “± 32”.

Next, the image quality adjustment apparatus 30 performs a virtual output signal calculation process when a virtual input signal is input to the adjustment target video display apparatus 10 (step S1-6). Specifically, the control unit 31 of the image quality adjustment device 30 receives the adjustment target input / output characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B)]. The virtual input / output characteristic data [x (R +, G +, B +), y (R +, G +, B +), Lv (R +, G +, B +)] is generated and the virtual characteristic data area of the data storage unit 32 is used. To remember. In this case, for example, a calculation method such as a known interpolation method is used.

Next, it is determined whether or not the reference output signal space is included in the virtual output signal space (step S1-7). Specifically, the control unit 31 of the image quality adjustment device 30 performs virtual input / output characteristic data [x (R +, G +, B +), y (R +, G +, B +), Lv as in step S1-3 described above. (R +, G +, B +)] is converted into a virtual output signal (x, y, Lv) coordinate system.

The control unit 31 then outputs the reference output signal (x
', y', Lv ') and the virtual output signal (x, y, Lv) are expressed in the same coordinate system (coordinate space) and are determined by the value of the virtual output signal (x, y, Lv) ( The virtual output signal space) is compared with the reference output signal space.

Here, when the reference output signal space is not included in the virtual output signal space (in the case of “NO” in step S1-7), the control unit 31 of the image quality adjustment device 30 performs the above-described step S1-5 and subsequent steps. Repeat the above process. More specifically, the control unit 31 expands the virtual input signal (R +, G +,...) By “± 32” with respect to the virtual input signal set when it is determined that the reference output signal space is not included. B +) is newly set (step S1-5). Then, the control unit 31 calculates a virtual output signal (x, y, Lv) when this virtual input signal (R +, G +, B +) is input (step S1-6), and the reference output signal space is a virtual output. It is determined whether or not the signal is included in the signal space (step S1-7).

On the other hand, as shown in FIG. 6, when the reference output signal space is included in the virtual output signal space (in the case of “YES” in step S1-7), the control unit 31 of the image quality adjustment device 30 performs the temporary LUT. Is calculated (step S1-8). Specifically, the control unit 31 performs reference input / output characteristic data [x ′ (R, G, B), y ′ (R, G, B), Lv ′ (R, G, B)] and virtual input Using the output characteristic data [x (R +, G +, B +), y (R +, G +, B +), Lv (R +, G +, B +)], an input signal that satisfies the above equations (1) to (3) (R, g, b) is calculated as a temporary input signal (r ′, g ′, b ′).

In this case, when there is no virtual output signal (x, y, Lv) that matches the measured reference output signal (x ′, y ′, Lv ′), the control unit 31 uses a known interpolation method. , Reference output signal (x ', y
A virtual output signal (x, y, Lv) matching “, Lv”) is calculated. Specifically, the control unit 31
Are the virtual input signal (R +, G +, B +) of the virtual output signal (x, y, Lv) in the vicinity of the reference output signal (x ′, y ′, Lv ′) and the reference output signal (x ′, y ′). , Lv ′) and nearby virtual output signals (x, y,
A virtual output signal (x, y, Lv) that matches the reference output signal (x ′, y ′, Lv ′) is calculated from weighting according to the distance to Lv).

Then, the control unit 31 associates the input video signal (R, G, B) and the temporary input signal (r ′, g ′, b ′) with each coordinate data of the three-dimensional matrix, and stores these data. And stored in the data storage unit 32. In this case, for example,
R ″ (R, G, B) = r ′ (7)
G ″ (R, G, B) = g ′ (8)
B ″ (R, G, B) = b ′ (9)
Is stored as follows. As a result, a temporary LUT for converting the input video signal (R, G, B) into the temporary input signal (r ′, g ′, b ′) is generated.

Next, the control unit 31 of the image quality adjustment apparatus 30 performs the LUT generation process by clipping the expanded space using the temporary LUT (step S1-9). Specifically, the control unit 31 determines that each element of the temporary input signals (r ′, g ′, b ′) is “0 to 255” in the generated temporary LUT.
The input signal (r, g, b) is within a range (range “0 to 255”) that the original input video signal (R, G, B) can take. Convert.

In the present embodiment, the control unit 31 substitutes “0” when the value of each element is smaller than “0”, and substitutes “255” when the value is larger than “255”. Specifically, for example, if (r ′, g ′, b ′) = (8, 12, -5), the control unit 31 (r, g, b) = (8, 1).
2, 0), and if (r ′, g ′, b ′) = (− 2, −3, −5), (r, g, b)
= (0,0,0), and if (r ′, g ′, b ′) = (280, −3,20), (r
, G, b) = (255, 0, 0).

The control unit 31 uses the value of the temporary LUT as it is (r ′ = r, g ′ =) for the signal (r ′, g ′, b ′) in which the value of each element is within “0 to 255”. g, b '= b).
As a result, the control unit 31 generates an LUT that converts the input video signal (R, G, B) into the input signal (r, g, b), and stores the LUT in the LUT data area of the data storage unit 32. In this case, similar to the LUT generated in step S1-4, the data is stored as in equations (4) to (6). Thus, the LUT creation process is completed.

Then, the control unit 31 writes the generated LUT in the LUT conversion circuit 15 of the adjustment target video display device 10 and holds the LUT. The LUT conversion circuit 15 converts the input video signal (R, G, B) by using the held LUT and outputs the input signal (r, g, b). As a result, the video display device 16 of the adjustment target video display device 10 is adjusted to approximate the reference output signal (x ′, y ′, Lv ′) when the input video signal (R, G, B) is input. Output signal (x, y, Lv) is output.

According to this embodiment, the following effects can be obtained.
In the present embodiment, the control unit 31 of the image quality adjustment device 30 outputs the input signal when the reference output signal space is not included in the adjustment target output signal space (in the case of “NO” in step S1-3). The expanded virtual input signal is set (step S1-5), and the corresponding virtual output signal calculation process is executed (step S1-6). The control unit 31 determines whether or not the reference output signal space is included in the virtual output signal space of the virtual output signal. If the reference output signal space is included (in the case of “YES” in step S1-7), the temporary LUT is determined. Is calculated (step S1-8). Further, the control unit 31 performs the LUT generation process by clipping the expanded space using the temporary LUT (step S1-9). Therefore, the LUT identifies the temporary input signal (r ′, g ′, b ′) from the virtual output signal (x, y, Lv) that matches the reference output signal, and this temporary input signal (r ′, g ′). , B ′) is generated by approximating the range that the original input video signal (R, G, B) can take. Since the reference output signal space and the adjustment target output signal space are nonlinear with complicated shapes, the input signal (r, g, b) is specified from the adjustment target output signal approximated to the reference output signal as in the prior art. When the LUT is generated using the input signals (r, g, b), different colors are obtained. Compared to this case, since the virtual input signal (R +, G +, B +) corresponding to the virtual output signal (x, y, Lv) matching the reference output signal (x ′, y ′, Lv ′) is used,
The difference in color tone can be reduced. Therefore, an image whose color tone is more similar to the image of the reference image display device 20 can be realized by the adjustment target image display device 10.

  In the present embodiment, when the reference output signal space is not included in the adjustment target output signal space (in the case of “NO” in step S1-3), the control unit 31 of the image quality adjustment device 30 extends the input signal. A virtual input signal is set (step S1-5). The control unit 31 calculates a virtual output signal corresponding to the virtual input signal (step S1-6), and determines whether or not the reference output signal space is included in the virtual output signal space of the virtual output signal (step S1-6). S1-7). If the virtual input signal is not included (in the case of “NO” in step S1-7), the control unit 31 expands the virtual input signal set at this time by “± 32”. (R +, G +, B +) is newly generated (step S1-5), and step S1-6 and step S1-7 are repeatedly executed. When the reference output signal space is included in the virtual output signal space (in the case of “YES” in step S1-7), the control unit 31 executes a temporary LUT calculation process (step S1-8). . For this reason, when the minimum required virtual output space including the reference output signal space is specified, the temporary signal conversion table is generated using the virtual input / output characteristic data of this virtual output signal. Thus, the number of virtual input / output characteristic data used for the process can be reduced, and a signal conversion table can be generated efficiently.

  In the present embodiment, the control unit 31 of the image quality adjustment apparatus 30 executes the LUT generation process using the temporary LUT (step S1-9). If the value of each element is smaller than “0”, Replace with “0” and replace with “255” if greater than “255”. Therefore, it is possible to generate a signal conversion table using input video signals (R, G, B) within a range that can be originally obtained by simple processing.

  In this embodiment, the control unit 31 of the image quality adjustment device 30 performs measurement processing of input / output characteristics of the adjustment target video display device 10 (step S1-2), and adjusts the adjustment target video display device 10 obtained by the measurement. An LUT was created using the target input / output characteristic data [x (R, G, B), y (R, G, B), Lv (R, G, B)]. For this reason, even when the characteristics of the individual adjustment target video display devices 10 are different, the input / output characteristics thereof are obtained more accurately, and the LUT corresponding to the input / output characteristics of the adjustment target video display device 10 is obtained. Can be generated.

Moreover, you may change the said embodiment as follows.
In the above embodiment, when the control unit 31 of the image quality adjustment apparatus 30 performs the LUT generation process by clipping the expanded space (step S1-9), the value of each element is smaller than “0”. In some cases, it was replaced with “0”, and when it was larger than “255”, it was replaced with “255”. The method of clipping the expanded space is not limited to this.

  In the above embodiment, the control unit 31 first performs the measurement process of the input / output characteristics of the reference video display device 20 in the LUT creation process (step S1-1). However, the measurement process of the input / output characteristics of the reference video display device 20 may not be performed every LUT creation process. Specifically, the reference input / output characteristic data of the reference video display device 20 targeted for image quality is stored in the data storage unit 32. In the process of creating the LUT to be stored in each adjustment target video display device 10, the above steps S1-2 to S1-9 are executed using the reference input / output characteristic data stored in the data storage unit 32. Thereby, the LUT of the adjustment target video display device 10 can be efficiently created. Further, even if the characteristics of the individual adjustment target video display devices 10 vary, the same reference input / output characteristic data is used, so that the color tone of the adjustment target video display device 10 is uniformly approximated to the reference video display device 20. be able to.

  In the above embodiment, the input video signal of the RGB system has been described as the input video signal input to the adjustment target video display device 10 and the reference video display device 20. However, the present invention is not limited to this, and other component system signals such as a luminance color difference signal (YPbPr signal) may be used.

  In the above embodiment, a liquid crystal display is used as the video display device (10, 20). However, the present invention is not limited to this, and any video display device that adjusts the image quality, such as a plasma display or a projector, may be used other than the liquid crystal display.

It is an internal block diagram of a video display apparatus, (a) shows an adjustment object video display apparatus, (b) shows a reference video display apparatus. The block diagram of the measuring apparatus containing the image quality adjustment apparatus which measures the input-output characteristic data of a video display apparatus, and produces LUT. The flowchart for demonstrating the process sequence of a LUT creation process. It is explanatory drawing explaining the input-output characteristic data of an adjustment target video display apparatus, (a) is RGB coordinate space, (b) is a reference output signal (x ', y', Lv ') coordinate space. Explanatory drawing explaining the input-output characteristic data of the virtual output signal with respect to the virtual input signal in RGB coordinate space. Explanatory drawing for demonstrating the concept in case the reference output signal space is included in the virtual output signal space.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Adjustment target video display device, 12, 22 ... Video processing circuit, 15 ... LUT conversion circuit, 16, 26 ... Video display device, 20 ... Reference video display device, 30 ... Image quality adjustment device, 31 ... Control unit, 32 ... Data storage unit, 40 ... display analyzer.

Claims (5)

An adjustment target characteristic storage means for storing an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table;
A reference characteristic storage means for storing a reference input / output characteristic of a reference output signal with respect to an input signal input to a reference video display device of an image quality target;
A system comprising control means for generating the signal conversion table,
The control means includes
Means for comparing a reference output signal space expressing the reference input / output characteristic with output signal coordinates and an adjustment target output signal space expressing the adjustment target input / output characteristics with output signal coordinates;
When the reference output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by expanding the input signal is set, and a virtual output signal when the virtual input signal is input to the adjustment target video display device is set. Virtual output calculation means for calculating using the adjustment target input / output characteristics stored in the adjustment target characteristic storage means;
Means for calculating a temporary signal conversion table using the virtual input / output characteristics of the virtual output signal and the reference input / output characteristics stored in the reference characteristic storage means;
When the input signal of the temporary signal conversion table is the virtual input signal, the input signal is limited to an input signal within a range that can be taken by the original input signal, and includes a limiting unit that calculates the signal conversion table. A system for generating a characteristic signal conversion table. The control means includes
Reference output signal measuring means for inputting an input signal changed at a predetermined interval to the reference video display device and acquiring a reference output signal corresponding to the input signal;
The adjustment target video display device further includes an adjustment target output signal measurement unit that inputs the input signal changed at the predetermined interval and acquires an adjustment target output signal corresponding to the input signal,
The virtual output calculation means includes
Means for executing a setting process for setting a virtual input signal expanded at the predetermined interval with respect to an input signal when it is determined that the reference output signal space is not included;
Means for executing a virtual space comparison process for comparing the virtual output signal space expressing the virtual input / output characteristics of the set virtual input signal with output signal coordinates and the reference output signal space;
When the reference output signal space is not included in the virtual output signal space, the setting process and the virtual space comparison process are repeated, and the reference output signal space is included in the virtual output signal space. 2. The signal conversion table generating system according to claim 1, further comprising means for calculating a virtual output signal corresponding to the virtual input signal set sometimes. The input signal is a component-type video signal composed of three elements,
When each element of the virtual input signal of the temporary signal conversion table is smaller than the range that the input signal can originally take, the limiting means limits the input signal to the minimum value of the range that the input signal can originally take. 3. The signal conversion table generation system according to claim 1, wherein the input signal is limited to a maximum value of a range that can be originally taken when the input signal is larger than a range to be obtained. An adjustment target characteristic storage means for storing an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table;
A reference characteristic storage means for storing a reference input / output characteristic of a reference output signal with respect to an input signal input to a reference video display device of an image quality target;
A method for generating the signal conversion table using a control means,
The control means includes
Comparing the reference output signal space expressing the reference input / output characteristics with output signal coordinates and the adjustment target output signal space expressing the adjustment target input / output characteristics with output signal coordinates;
When the reference output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by expanding the input signal is set, and a virtual output signal when the virtual input signal is input to the adjustment target video display device is set. A virtual output calculation step of calculating using the adjustment target input / output characteristics stored in the adjustment target characteristic storage means;
Calculating a temporary signal conversion table using the virtual input / output characteristics of the virtual output signal and the reference input / output characteristics stored in the reference characteristic storage means;
When the input signal of the temporary signal conversion table is the virtual input signal, the limiting step of calculating the signal conversion table is performed by limiting the input signal within a range that the original input signal can take. A method for generating a characteristic signal conversion table. An adjustment target characteristic storage means for storing an adjustment target input / output characteristic of an adjustment target output signal with respect to an input signal input to an adjustment target video display device that performs image quality adjustment using a signal conversion table;
A reference characteristic storage means for storing a reference input / output characteristic of a reference output signal with respect to an input signal input to a reference video display device of an image quality target;
A program for generating the signal conversion table using a control means,
The control means;
Means for comparing a reference output signal space expressing the reference input / output characteristic with output signal coordinates and an adjustment target output signal space expressing the adjustment target input / output characteristics with output signal coordinates;
When the reference output signal space is not included in the adjustment target output signal space, a virtual input signal obtained by expanding the input signal is set, and a virtual output signal when the virtual input signal is input to the adjustment target video display device is set. Virtual output calculation means for calculating using the adjustment target input / output characteristics stored in the adjustment target characteristic storage means,
Means for calculating a temporary signal conversion table using virtual input / output characteristics of the virtual output signal and reference input / output characteristics stored in the reference characteristic storage means; and an input signal of the temporary signal conversion table is the virtual input In the case of a signal, a signal conversion table generation program that restricts the input signal to a range that can be taken by the original input signal and functions as a limiting unit that calculates the signal conversion table.

Images