Video signal processing device and program

Abstract

This paper objectively evaluates the conversion performance of 3D-LUTs, which are used to convert video signals into video signals of different formats. [Solution] A range conversion unit 12 of a video signal processing device 1 converts the range of a video signal generated from a test pattern image in accordance with a first range conversion type. A table conversion unit 13 converts the range-converted video signal into a normalized signal value in accordance with a range type reflecting the first range conversion type, converts the normalized signal value by performing interpolation processing in accordance with an interpolation method type using a 3D-LUT, and converts the normalized signal value into a video signal in accordance with the range type reflecting the first range conversion type. A range conversion unit 14 converts the range of the converted video signal in accordance with a second range conversion type. An evaluation unit 15 generates a quantitative evaluation value, etc., based on the correct image and an image of the range-converted video signal. A display unit 16 displays the quantitative evaluation value, etc. on a screen.

Description

[Technical Field]

[0001] The present invention relates to a video signal processing device and a program for evaluating a look-up table (LUT) used when converting a video signal into a video signal of a different format. [Background technology]

[0002] When producing a video signal for a program, if the video parameters used in the program production do not match the video parameters specified in the broadcast wave, the video signal must be converted into a video signal of a different format so that the video parameters of the produced video signal match the video parameters of the broadcast wave.

[0003] For example, when converting the dynamic range system or color space of a video signal, an LUT is generally used (see, for example, Patent Documents 1 and 2).

[0004] The technology in Patent Document 1 uses a 3D-LUT to convert the color gamut to a color system with a narrower color gamut, thereby obtaining a color bar for adjusting the display, and then matching the color bar at the signal level to an existing color bar expressed in that color system.

[0005] Furthermore, the technology of Patent Document 2 reduces conversion errors and the amount of data in the 3D-LUT by performing interpolation processing using a high-order equation when converting a video signal into a video signal of a different format using a 3D-LUT.

[0006] Here, it is assumed that a 3D-LUT is used to convert the RGB signal values ​​of an input video signal into the RGB signal values ​​of an output video signal. The 3D-LUT is a table that defines the relationship between the RGB signal values ​​of the input video signal and the RGB signal values ​​of the output video signal. Specifically, the 3D-LUT associates a cube whose vertices are lattice points arranged at predetermined intervals in a three-dimensional space that represents the RGB signal values ​​of the input video signal with a three-dimensional region in the three-dimensional space that represents the RGB signal values ​​of the output video signal, the vertices of which correspond to the lattice points of the input video signal. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6482232 [Patent Document 2] Patent No. 7025904 Summary of the Invention [Problem to be solved by the invention]

[0008] When a video signal is converted into a video signal of a different format using such a 3D-LUT, the conversion performance varies depending on the number of lattice points when the 3D-LUT is generated, the evenness of the spacing between the lattice points, and the conversion algorithm.

[0009] In addition to these factors, this conversion performance also varies depending on the signal interpolation process implemented in the hardware and software that executes the conversion process using the 3D-LUT, and the difference between the range (full range or limited range (narrow range)) of the input and output video signals (levels) assumed when the 3D-LUT was created and the range interpretation within the conversion device. Limited range is a range that is narrower than full range.

[0010] Furthermore, depending on the combination of the number of lattice points in the 3D-LUT, the interpolation technique, the range of the assumed input and output video signals, etc., discontinuities may occur in the gradation of the converted video signal.

[0011] The conversion performance of such 3D-LUTs can only be evaluated subjectively by the user of the 3D-LUT, who actually views the image of the converted video signal. This subjective evaluation will produce different evaluation results depending on the evaluator. For this reason, a method for objectively evaluating the conversion performance of 3D-LUTs, rather than subjectively, has been desired.

[0012] Furthermore, only the creator of the 3D-LUT can determine whether the 3D-LUT was generated assuming the full range or limited range of input and output video signals, and it is difficult for a user of the 3D-LUT to determine this based solely on the numerical information described in the 3D-LUT.

[0013] If the range of input and output video signals when converting video signals using a 3D-LUT differs from the range of input and output video signals assumed when the 3D-LUT was generated, the overall gradation expression from dark to light areas of the converted video signal will differ from what was expected.

[0014] When using a 3D-LUT, if the range of input and output video signals assumed when the 3D-LUT was created could be known in advance, such problems would not occur. For this reason, a method for determining the range of input and output video signals assumed when the 3D-LUT was created has been desired.

[0015] Therefore, the present invention has been made to solve the above-mentioned problems, and its object is to provide a video signal processing device and program that can objectively evaluate the conversion performance of a 3D-LUT used when converting a video signal into a video signal of a different format. [Means for solving the problem]

[0016] In order to solve the above problem, a video signal processing device according to claim 1 is a video signal processing device for evaluating a 3D-LUT used when converting a video signal into a video signal of a different format, the video signal processing device comprising: a storage unit storing a test pattern image, a correct image obtained by converting the test pattern image using a predetermined conversion algorithm, and the 3D-LUT describing the relationship between normalized signal values ​​of an input video signal and normalized signal values ​​of an output video signal; a test pattern signal generation unit reading out the test pattern image from the storage unit and generating a test pattern video signal from the test pattern image; a first range conversion unit converting the range of the test pattern video signal generated by the test pattern signal generation unit in accordance with a first range conversion type preset by a user and outputting the converted video signal; a table conversion unit that converts the values ​​of the video signal into normalized signal values ​​of an input video signal in accordance with a range type indicating a type of an interpolation method, reads out the 3D-LUT from the storage unit, and converts the normalized signal values ​​of the input video signal into normalized signal values ​​of an output video signal by performing interpolation processing using the 3D-LUT in accordance with an interpolation method type preset by a user, converts the normalized signal values ​​of the output video signal into video signal values ​​in accordance with the range type, and outputs the converted video signals; a second range conversion unit that converts the range of the video signal output by the table conversion unit in accordance with a second range conversion type preset by a user; and an evaluation unit that reads out the reference image from the storage unit and generates an evaluation value for evaluating the 3D-LUT based on the reference image and an image of the video signal converted by the second range conversion unit.

[0017] A video signal processing device according to claim 2 is a video signal processing device in a system including an external device that converts an input video signal using a 3D-LUT, which is a table for converting an input video signal into an output video signal of a different format, the 3D-LUT describing the relationship between normalized signal values ​​of the input video signal and normalized signal values ​​of the output video signal, and a video signal processing device that evaluates the 3D-LUT, wherein the external device converts the value of the video signal into a normalized signal value of the input video signal according to a range type indicating a type of range of the input video signal, converts the normalized signal value of the input video signal into a normalized signal value of an output video signal by performing a predetermined interpolation process using the 3D-LUT, converts the normalized signal value of the output video signal into a video signal value according to the range type, and when outputting the video signal, the video signal processing device converts a test pattern image and a predetermined a test pattern signal generating unit that reads out the test pattern image from the storage unit and generates a test pattern video signal from the test pattern image; a first range conversion unit that converts the range of the test pattern video signal generated by the test pattern signal generating unit in accordance with a first range conversion type preset by a user and outputs the converted video signal to the external device; a second range conversion unit that converts the range of the video signal output by the external device in accordance with a second range conversion type preset by a user; and an evaluation unit that reads out the reference image from the storage unit and generates an evaluation value for evaluating the 3D-LUT based on the reference image and an image of the video signal output by the external device.

[0018] Furthermore, the video signal processing device of claim 3 is characterized in that, in the video signal processing device of claim 1 or 2, the range type is either a full range having a predetermined range or a limited range that is narrower than the full range, and each of the first range conversion type and the second range conversion type is either a conversion from the full range to the limited range, a conversion from the limited range to the full range, or no conversion.

[0019] Furthermore, a program according to claim 4 is characterized in that it causes a computer to function as the video signal processing according to claim 1 or 2. [Effects of the Invention]

[0020] As described above, according to the present invention, it is possible to objectively evaluate the conversion performance of a 3D-LUT used when converting a video signal into a video signal of a different format. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a block diagram showing an example of the configuration of a video signal processing device according to an embodiment of the present invention; [Figure 2] 4 is a flowchart illustrating an example of processing performed by a video signal processing device according to an embodiment of the present invention. [Figure 3] FIG. 10 is a diagram illustrating an example of a test pattern image. [Figure 4] (1) is a diagram showing an example of a correct image obtained by converting a test pattern image using a first conversion algorithm. (2) is a diagram showing an example of a correct image obtained by converting a test pattern image using a second conversion algorithm different from (1). [Figure 5] FIG. 10 is a diagram illustrating an example of the data structure of a 3D-LUT. [Figure 6] 10A and 10B are diagrams showing examples of an image of a correct video signal and an image of a conversion result. [Figure 7]10 is a diagram showing the correspondence between the grid point numbers of a 3D-LUT, the values ​​(10-bit values) of input video signals assigned to the grid points, and normalized signal values ​​relative to the values ​​of the input video signals. FIG. [Figure 8] 10A and 10B are diagrams illustrating internal processing and output video signals when converting an input video signal using a 3D-LUT when the 10-bit value of the input video signal is 64 and its signal level is a 0% video signal level. [Figure 9] FIG. 10 is a diagram showing an example of a radar chart display of quantitative evaluation values. DETAILED DESCRIPTION OF THE INVENTION

[0022]

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a block diagram showing an example of the configuration of a video signal processing device according to an embodiment of the present invention. This video signal processing device 1 includes a storage unit 10, a test pattern signal generating unit 11, range conversion units 12 and 14, a table conversion unit 13, an evaluation unit 15, and a display unit 16.

[0023] The video signal processing device 1 inputs a test pattern image, a correct image, and a 3D-LUT, converts the video signal of the test pattern image using the 3D-LUT, quantitatively evaluates the conversion results, and displays the evaluation results on the screen to present the performance of the 3D-LUT to the user.

[0024] As shown in FIG. 1, a system including a video signal processing device 1 and an external device 2 may quantitatively evaluate the conversion results using a 3D-LUT and display the evaluation results on a screen.

[0025] In this case, the video signal processing device 1 includes a storage unit 10, a test pattern signal generating unit 11, range conversion units 12 and 14, an evaluation unit 15, and a display unit 16. The video signal processing device 1 receives a test pattern image and a correct answer image and stores them in the storage unit 10, outputs a video signal generated from the test pattern image to the external device 2, and receives a video signal converted using the 3D-LUT to be evaluated that has been received from the external device 2. The video signal processing device 1 then quantitatively evaluates the conversion result and displays the evaluation result on a screen to present the performance of the 3D-LUT to the user.

[0026] The external device 2 receives the 3D-LUT, receives the video signal from the video signal processing device 1, performs processing similar to that of a table conversion unit 13 (described later), and outputs the converted video signal to the video signal processing device 1. The external device 2 uses a preset fixed interpolation method as the type of interpolation method. The types of interpolation method will be described later.

[0027] 2 is a flowchart showing an example of processing performed by the video signal processing device 1 according to the embodiment of the present invention. Hereinafter, processing performed by each component of the video signal processing device 1 will be described with reference to FIGS.

[0028] (Storage unit 10) The video signal processing device 1 receives a test pattern image, a reference image, and a 3D-LUT (step S201), and stores these data in the storage unit 10. The test pattern image and the reference image are assumed to have information added thereto as to whether they are full range (F) or limited range (L). In other words, the test pattern image is assumed to have been generated in the full range or limited range, and the reference image is assumed to have been generated in the full range or limited range.

[0029] The ground truth image is an image generated from a test pattern image using a predetermined transformation algorithm. The 3D-LUT is a table to be evaluated, and is either generated using the same predetermined transformation algorithm as that used to generate the ground truth image, or the transformation algorithm is unknown.

[0030] As a result, the storage unit 10 stores the test pattern image to which the full range or limited range information is added, the correct image to which the full range or limited range information is added, and the 3D-LUT to be evaluated.

[0031] 3 is a diagram showing an example of a test pattern image, which is a verification image for evaluating a 3D-LUT to be evaluated.

[0032] Fig. 4(1) is a diagram showing an example of a correct image obtained by converting a test pattern image using the first conversion algorithm. Specifically, this correct image is an image obtained by converting the test pattern image shown in Fig. 3 using the first conversion algorithm that converts a video signal with a wide color gamut of HDR (High Dynamic Range) into a video signal with a standard color gamut of SDR (Standard Dynamic Range).

[0033] FIG. 4(2) is a diagram showing an example of a correct image obtained by converting the test pattern image using a second conversion algorithm different from that in FIG. 4(1).

[0034] 5 is a diagram showing an example of the data structure of a 3D-LUT. A 3D-LUT is a table that describes the relationship between the RGB signal values ​​of an input video signal and the RGB signal values ​​of an output video signal when a certain conversion algorithm is used. In other words, a 3D-LUT defines the relationship between the RGB signal values ​​of an input video signal and the RGB signal values ​​of an output video signal when a certain conversion algorithm is used, and this relationship is organized into a table.

[0035] 5 is a table having 33 grid points, and defines the relationship between normalized signal values ​​of RGB values ​​(e.g., 10-bit values) of an input video signal and normalized signal values ​​of RGB values ​​of an output video signal. As normalized signal values, 0% video signal level and 100% video signal level correspond to 0 and 1, respectively, and values ​​in the range from 0 to 1 are used for the full range, and values ​​in the range from -0.06849 to 1.09018 are used for the limited range.

[0036] In the example of the 3D-LUT shown in Fig. 5, each of the 33 grid points is configured with normalized RGB signal values ​​of the input video signal and normalized RGB signal values ​​of the output video signal. In contrast, another example of a 3D-LUT may be configured with 10-bit RGB values ​​of the input video signal and 10-bit RGB values ​​of the output video signal. Furthermore, the number of grid points may be a number other than 33.

[0037] Furthermore, the 10-bit RGB values ​​of a video signal take values ​​between 0 and 1023 in the full range, with 0 in the normalized signal value corresponding to the 10-bit value 0 and 1 corresponding to the 10-bit value 1023. In the limited range, the values ​​take values ​​between 4 and 1019, with 0 in the normalized signal value corresponding to the 10-bit value 64 and 1 corresponding to the 10-bit value 940.

[0038] Returning to Figures 1 and 2, unless the conversion algorithm used when converting the test pattern image to generate the correct image matches the conversion algorithm used when generating the 3D-LUT, a difference will occur between the correct image generated using the conversion algorithm and the image of the video signal converted using the 3D-LUT.

[0039] Of the test pattern image and correct image input to the video signal processing device 1, the correct image is an image obtained by converting the test pattern image using a predetermined conversion algorithm. The 3D-LUT input to the video signal processing device 1 is a table to be evaluated, and may be a table generated using the same predetermined conversion algorithm as used to generate the correct image, or a table whose conversion algorithm is unknown. By using the video signal processing device 1, a user of the 3D-LUT can quantitatively check the quality of the conversion results due to, for example, discrepancies in range conversion or differences in the type of interpolation method in the former case. In the latter case, the user can quantitatively check the conversion quality using the 3D-LUT and verify the expected range of input and output video signals.

[0040] (Test pattern signal generator 11) The test pattern signal generating section 11 has a function of generating a test pattern video signal consisting of a series of images using a test pattern image as a signal source.

[0041] Specifically, the test pattern signal generating unit 11 reads out a test pattern image with full range or limited range information added from the memory unit 10, and inputs the range type (full range or limited range), spatial resolution, frame rate, color gamut, dynamic range, bit depth, etc. that have been preset by the user.

[0042] The test pattern signal generating unit 11 generates (creates) a test pattern video signal from the test pattern image based on the range type, etc. (step S202), and outputs this to the range converting unit 12. Information on full range or limited range that reflects the range type is added to the test pattern video signal.

[0043] The range type preset by the user corresponds to the range (full range or limited range) of the test pattern video signal output from the test pattern signal generating unit 11. The user selects one of the full range and limited range as the range of the test pattern video signal, and the selected range is input to the test pattern signal generating unit 11.

[0044] That is, the test pattern signal generating unit 11 generates a test pattern video signal to which full range or limited range information reflecting the range type is added from a test pattern image to which full range or limited range information is added based on the range type.

[0045] For example, if a limited range is added to the test pattern image (if the test pattern image is generated with a limited range), when the user inputs the limited range as the range type preset by the user, the test pattern signal generating unit 11 generates a test pattern video signal using the range of the test pattern image read out from the memory unit 10 as is.

[0046] On the other hand, when a full range is added to the test pattern image (when the test pattern image is generated in the full range), when the limited range is input as the range type preset by the user, the test pattern signal generating unit 11 generates a test pattern video signal from the test pattern image by converting the full range of the test pattern image into the limited range of the test pattern video signal.

[0047] The spatial resolution is the number of vertical and horizontal pixels of the test pattern image. The test pattern signal generating unit 11 obtains the number of vertical and horizontal pixels from the test pattern image and converts the obtained number of pixels into the number of vertical and horizontal pixels indicated by the spatial resolution set by the user. Alternatively, instead of inputting the spatial resolution set by the user, the test pattern signal generating unit 11 may obtain the number of vertical and horizontal pixels from the test pattern image read from the storage unit 10 and treat this as the number of vertical and horizontal pixels indicated by the spatial resolution set by the user.

[0048] The user selects one of a plurality of frame rates defined by, for example, Recommendation ITU-R BT.2020 or BT.2100 as the frame rate, and inputs it to the test pattern signal generating unit 11. The user selects one of the standard color gamut and the wide color gamut as the color gamut, and inputs it to the test pattern signal generating unit 11. The user selects one of the HDR and SDR as the dynamic range, and inputs it to the test pattern signal generating unit 11.

[0049] The bit depth is usually selected by the user as 10 bits and input to the test pattern signal generating unit 11. If the test pattern image consists of 16-bit data, this needs to be converted to 10 bits, so the test pattern signal generating unit 11 generates a test pattern video signal by dividing the 16-bit data of the test pattern image by 2^6 (shifting it to the right by 6 bits).

[0050] The video signal processing device 1 may include a storage unit that stores range types and the like preset by a user, and the test pattern signal generating unit 11 may read out the range types and the like from the storage unit. The same applies to the evaluation unit 15 described later.

[0051] Furthermore, if the external device 2 is present, the test pattern signal generating section 11 may output to the external device 2 a test pattern video signal to which information on full range or limited range has been added.

[0052] (Range conversion unit 12) The range conversion section 12 has a function of converting the range of the test pattern video signal into a full range or a limited range.

[0053] Specifically, the range conversion unit 12 inputs a test pattern video signal to which full range or limited range information has been added from the test pattern signal generation unit 11, and also inputs a first range conversion type (conversion from full range to limited range, conversion from limited range to full range, or no conversion) preset by the user.

[0054] The range conversion unit 12 converts the range of the test pattern video signal in accordance with the first range conversion type (step S203), and outputs the range-converted video signal to the table conversion unit 13. Full range or limited range information reflecting the first range conversion type is added to the range-converted video signal.

[0055] For example, if full-range information is added to the test pattern video signal, the range conversion unit 12 receives information indicating conversion from full range to limited range as the first range conversion type preset by the user. In this case, the range conversion unit 12 calculates the 10-bit value V of the test pattern video signal to which the full-range information is added by the following formula: in is converted to the 10-bit value V of the video signal with limited range information added. out Convert to. [Formula 1] V out =(V in / 1023)×876+64 (1)

[0056] On the other hand, if full-range information is added to the test pattern video signal, and the range conversion unit 12 receives information indicating conversion from limited range to full range or information indicating no conversion as the first range conversion type preset by the user, the range conversion unit 12 outputs the input test pattern video signal with full-range information added as is, as a video signal with full-range information added, without performing any conversion processing on the test pattern video signal with full-range information added.

[0057] Also, for example, when limited range information is added to the test pattern video signal, the range conversion unit 12 inputs information indicating conversion from limited range to full range as the first range conversion type preset by the user. In this case, the range conversion unit 12 calculates the 10-bit value V of the test pattern video signal to which the limited range information is added by the following formula: in is converted to the 10-bit value V of the video signal with full-range information added. out Convert to. [Formula 2] V out =((V in -64) / 876)×1023 (2)

[0058] On the other hand, if limited range information is added to the test pattern video signal, and the range conversion unit 12 receives information indicating conversion from full range to limited range or information indicating no conversion as the first range conversion type preset by the user, the range conversion unit 12 outputs the input test pattern video signal with limited range information added as is, without performing any conversion processing on the test pattern video signal with limited range information added.

[0059] The video signal processing device 1 may include a storage unit that stores a first range conversion type preset by a user, and the range conversion unit 12 may read out the first range conversion type from the storage unit. The same applies to the range conversion unit 14 that handles a second range conversion type, which will be described later.

[0060] Furthermore, if the external device 2 is present, the range conversion unit 12 outputs to the external device 2 the range-converted video signal to which the information on full range or limited range has been added.

[0061] (Table conversion unit 13) The table conversion unit 13 has a function of converting the range-converted video signal by performing interpolation processing using a 3D-LUT.

[0062] Specifically, the table conversion unit 13 reads out the 3D-LUT from the memory unit 10, inputs the range-converted video signal with full-range or limited-range information added from the range conversion unit 12, and inputs the type of interpolation method previously set by the user.

[0063] As the type of interpolation method, for example, either a commonly used interpolation method called cubic interpolation or linear interpolation, or an interpolation method called triangular pyramid interpolation is set.

[0064] The table conversion unit 13 converts the 10-bit value of the input video signal into a normalized signal value in accordance with full range or limited range information added to the input video signal.

[0065] Specifically, when full-range information is added to the input video signal, the table conversion unit 13 converts the 10-bit value X of the video signal to which the full-range information is added into a normalized signal value X ranging from 0 to 1 using the following formula: n Convert to. [Formula 3] X n =X / 1023 (3)

[0066] On the other hand, when limited range information is added to the input video signal, the table conversion unit 13 converts the 10-bit value X of the video signal to which the limited range information is added into a normalized signal value X in the range from −0.06849 to 1.09018 by the following formula: n Convert to. [Formula 4] X n =(X-64) / 876 (4)

[0067] The table conversion unit 13 uses the 3D-LUT to perform interpolation processing according to the interpolation method type preset by the user, thereby converting the normalized signal values ​​of the input video signal (the normalized signal values ​​of the input video signal) into normalized signal values ​​of the output video signal (step S204). The normalized signal values ​​of the output video signal take values ​​in the same range as the normalized signal values ​​of the input video signal.

[0068] The table conversion unit 13 converts the normalized signal value of the output video signal into a video signal in accordance with the full range or limited range information added to the input video signal. The table conversion unit 13 then adds the same information as the full range or limited range information added to the input video signal to the converted video signal, and outputs the table-converted video signal to the range conversion unit 14.

[0069] Specifically, when full-range information is added to the input video signal, the table conversion unit 13 calculates a normalized signal value X in the range from 0 to 1 using the following formula: n is converted into a 10-bit value X of the video signal. [Formula 5] X=1023×X n ···(5)

[0070] On the other hand, when limited range information is added to the input video signal, the table conversion unit 13 calculates a normalized signal value X in the range from −0.06849 to 1.09018 by the following formula: n is converted into a 10-bit value X of the video signal. [Formula 6] X=876×X n +64 (6)

[0071] The video signal processing device 1 may include a storage unit that stores types of interpolation methods preset by the user, and the table conversion unit 13 may read out the types of interpolation methods from the storage unit.

[0072] (Range conversion unit 14) The range conversion unit 14 has a function of converting the range of the video signal converted using the 3D-LUT (video signal after table conversion) into a full range or limited range.

[0073] Specifically, the range conversion unit 14 inputs the video signal after table conversion to which full range or limited range information has been added from the table conversion unit 13, and also inputs the second range conversion type (conversion from full range to limited range, conversion from limited range to full range, or no conversion) preset by the user.

[0074] Range conversion unit 14 performs the same process as range conversion unit 12. That is, range conversion unit 14 converts the range of the table-converted video signal in accordance with the second range conversion type to generate a conversion result (step S205), and outputs the range-converted video signal as an image sequence of the conversion result to evaluation unit 15. Full range or limited range information reflecting the second range conversion type is added to the range-converted video signal.

[0075] For example, when full-range information is added to the video signal after table conversion, the range conversion unit 14 inputs information indicating conversion from full range to limited range as the second range conversion type preset by the user. In this case, the range conversion unit 14 calculates the video signal V after table conversion to which full-range information is added, using the above-mentioned formula (1). in The video signal V out Convert to.

[0076] On the other hand, if full-range information is added to the video signal after table conversion, it is assumed that range conversion unit 14 receives information indicating conversion from limited range to full range or information indicating no conversion as the second range conversion type preset by the user. In this case, range conversion unit 14 outputs the input video signal after table conversion to which full-range information has been added as is as a video signal to which full-range information has been added without performing any conversion processing on the video signal.

[0077] Furthermore, for example, when limited range information is added to the video signal after table conversion, the range conversion unit 14 inputs information indicating conversion from limited range to full range as the second range conversion type preset by the user. In this case, the range conversion unit 14 calculates the video signal V after table conversion to which the limited range information is added, using the above-mentioned formula (2). in The full-range information is added to the video signal V out Convert to.

[0078] On the other hand, if limited range information is added to the table-converted video signal, and the range conversion unit 14 receives information indicating conversion from full range to limited range or information indicating no conversion as the second range conversion type preset by the user, the range conversion unit 14 outputs the input table-converted video signal to which the limited range information has been added as is, without performing any conversion processing on the video signal.

[0079] If an external device 2 is present, the range conversion unit 14 receives the table-converted video signal with full-range or limited-range information added from the external device 2. The range conversion unit 14 then performs the same processing as described above, and outputs the range-converted video signal with full-range or limited-range information added to the evaluation unit 15 as an image sequence resulting from the conversion.

[0080] (Evaluation Section 15) The evaluation unit 15 has a function of comparing the conversion result of the 3D-LUT, which is the video signal whose range has been converted by the range conversion unit 14, with the correct image, and performing quantitative evaluation.

[0081] Specifically, the evaluation unit 15 inputs the range-converted video signal (the image sequence resulting from the conversion) to which full range or limited range information has been added from the range conversion unit 14, and also reads out the correct image to which full range or limited range information has been added from the storage unit 10. The evaluation unit 15 also inputs the range type (full range or limited range), spatial resolution, frame rate, color gamut, dynamic range, bit depth, etc., which have been preset by the user.

[0082] The evaluation unit 15, like the test pattern signal generation unit 11, generates a correct video signal from the correct image based on the range type and the like.

[0083] The evaluation unit 15 compares the correct image signal generated from the correct image and the range-converted image signal (the image sequence resulting from the conversion) to generate evaluation values ​​such as a quantitative evaluation value and a range setting verification result (step S206).The evaluation unit 15 then outputs the quantitative evaluation value, the range setting verification result, and the like to the display unit 16.

[0084] FIG. 6 is a diagram showing examples of an image of a correct video signal and an image of the conversion result (an image of the video signal after range conversion input by the evaluation unit 15), and shows an image of the correct video signal, the number of lattice points of the 3D-LUT, an image of the conversion result when the interpolation method type is cubic interpolation (linear interpolation), and an image of the conversion result when the interpolation method type is triangular pyramid interpolation.

[0085] As shown in Figure 6, factors that cause differences between the image of the correct video signal and the image resulting from conversion include the number of grid points described in the 3D-LUT, the type of interpolation method used in conversion using the 3D-LUT, the range (full range or limited range) assumed for the input and output video signals in the 3D-LUT, the conversion algorithm, etc. These factors can cause the color representation of the image to differ, discontinuities in the gradation of the image resulting from conversion, and other degradations in the image quality of the image resulting from conversion.

[0086] Therefore, the evaluation unit 15 calculates quantitative evaluation values, such as PSNR (Peak Signal to Noise Ratio) and SSIM (Structural Similarity Index Measure), using the image of the correct video signal and the image of the conversion result as objective evaluation indices for evaluating image quality degradation.

[0087] PSNR is an index of image quality degradation in the converted image relative to the correct video signal image, with a larger value indicating less degradation and a smaller value indicating more degradation. SSIM is an index of image quality degradation in the converted image relative to the correct video signal image, plus an index of similarity indicating how similar the structures of the two images are. A larger value indicates less degradation and more similarity, and a smaller value indicates more degradation and less similarity. Since the methods for calculating PSNR and SSIM are known, detailed explanations are omitted here.

[0088] On the other hand, the quantitative evaluation values ​​of PSNR and SSIM used to evaluate image quality degradation alone cannot be used to determine whether color reproduction is correct or whether discontinuity in gradation has occurred. Therefore, the evaluation unit 15 calculates quantitative evaluation values ​​used to evaluate color reproduction and quantitative evaluation values ​​used to evaluate discontinuity in gradation.

[0089] To evaluate color reproduction, the evaluation unit 15 calculates the color difference ΔE for each pixel using the image of the correct video signal and the image of the conversion result. ab Calculate the color difference ΔE for each pixel ab Maximum color difference ΔEab,max and average color difference ΔE ab,mean Furthermore, in order to evaluate discontinuity in gradation, the evaluation unit 15 calculates deviations in maximum luminance in the horizontal and vertical directions using the image of the correct video signal and the image of the conversion result.

[0090] Specifically, the evaluation unit 15 converts the RGB values ​​of the same image coordinates (pixel positions) into the CIELAB color space for each of the image of the correct video signal and the image of the conversion result, and calculates the correct lightness and color coordinates (L ans ,a ans ,b ans ) and the lightness and color coordinates of the converted result (L conv ,a conv ,b conv Then, the evaluation unit 15 calculates the distance between these values ​​for each pixel as a color difference ΔE ab is required. [Formula 7] ΔE ab =√{(L ans -L conv ) 2 +(a ans -a conv ) 2 +(b ans -b conv ) 2} ···(7)

[0091] Furthermore, the evaluation unit 15 calculates the color difference ΔE ab The maximum color difference ΔE ab The pixel having the color difference ΔE ab The maximum color difference ΔE ab,max Furthermore, the evaluation unit 15 sets the color difference ΔE ab The average value is calculated and the average value is used as the average color difference ΔE ab,mean Set as.

[0092] The evaluation unit 15 also compares the degree of change in horizontal luminance in the image of the correct video signal with the degree of change in horizontal luminance in the corresponding converted image, and calculates the deviation of maximum luminance in the horizontal direction based on the difference. The evaluation unit 15 calculates the deviation of maximum luminance in the vertical direction in the same way as it calculates the deviation of maximum luminance in the horizontal direction.

[0093] The evaluation unit 15 evaluates the PSNR, SSIM, and color difference ΔE ab , maximum color difference ΔE ab,max , average color difference ΔE ab,mean , and the quantitative evaluation values ​​of the deviations of maximum luminance in the horizontal and vertical directions are output to the display unit 16.

[0094] Furthermore, regarding the discrepancy between the level of the correct video signal generated from the correct image and the level of the video signal after range conversion input from the range conversion unit 14, the evaluation unit 15 compares the full range or limited range information attached to the correct video signal, the 10-bit value and video signal level of the image of the correct video signal with the full range or limited range information attached to the video signal after range conversion, and the 10-bit value and video signal level of the image of the video signal after range conversion (image as a result of conversion), to compare and evaluate which combination of user setting patterns will result in the correct conversion, and obtains the range setting verification result.

[0095] The combination of user-set patterns includes a range type etc. (user-set information a) set in the test pattern signal generating unit 11, a first range conversion type (user-set information b) set in the range conversion unit 12, an interpolation method type (user-set information c) set in the table conversion unit 13, a second range conversion type (user-set information d) set in the range conversion unit 14, and a range type etc. (user-set information e) set in the evaluation unit 15.

[0096] For example, a user may prepare multiple sets (e.g., five sets) of user setting information a, b, c, d, and e as combinations of user setting patterns. The first set of patterns may be user setting information a1, b1, c1, d1, and e1, the second set of patterns may be user setting information a2, b2, c2, d2, and e2, and so on, and the fifth set of patterns may be user setting information a5, b5, c5, d5, and e5.

[0097] The evaluation unit 15 inputs, from the range conversion unit 14, a sequence of converted images, which are video signals after range conversion, for each of the first to fifth sets of patterns using the test pattern image and correct image input by the video signal processing device 1 for the 3D-LUT to be evaluated that has been input by the video signal processing device 1.

[0098] Then, for each of the patterns from the first set to the fifth set, the evaluation unit 15 compares the full range or limited range information attached to the correct video signal, the 10-bit value of the image of the correct video signal, and the video signal level with the full range or limited range information attached to the video signal after range conversion, and the 10-bit value of the image of the video signal after range conversion (the image resulting from the conversion), and obtains a range setting verification result as the comparison result, which reflects, for example, the degree of similarity between the two.

[0099] For example, it is assumed that the range setting verification result indicates that the degree of similarity determined for the second set of patterns is the highest, that is, the full-range or limited-range information of the correct video signal generated from the correct image and the video signal after range conversion obtained under the second set of patterns match, and the 10-bit values ​​and video signal levels of the images of both video signals match within a predetermined threshold range.

[0100] Here, the range type of user setting information a2 constituting the second set of patterns (range type set in test pattern signal generating unit 11) is limited range, user setting information b2 (first range conversion type set by range conversion unit 12) is limited range, the interpolation method type of user setting information c2 (interpolation method type set in table conversion unit 13) is cubic interpolation (linear interpolation), user setting information d2 (second range conversion type set by range conversion unit 14) is limited range, and the range type of user setting information e2 (range type set in evaluation unit 15) is limited range.

[0101] Then, the display unit 16 described later displays the range setting verification results and the contents of the user-set pattern combination on the screen, allowing the user to determine that the range of the input video signal that was assumed when the 3D-LUT to be evaluated was generated is a limited range, and that the range of the output video signal is also a limited range.

[0102] Furthermore, the user may change the user setting pattern while checking the quantitative evaluation value and range setting verification result (obtained by the evaluation unit 15) displayed on the screen of the display unit 16 described below, and have the evaluation unit 15 obtain the quantitative evaluation value and range setting verification result under the changed user setting pattern.

[0103] In this case, for example, the user may leave the user setting information a, b, c, d, and e the same among the user setting information a, b, d, and e, and change only the user setting information c (type of interpolation method). This allows the user to compare the quantitative evaluation values ​​and range setting verification results, etc., when the interpolation method type is cubic interpolation (linear interpolation) with the quantitative evaluation values ​​and range setting verification results, etc., when the interpolation method type is triangular pyramid interpolation, and thus allows the user to select a more suitable type of interpolation method.

[0104] 7 is a diagram showing the correspondence between the grid point numbers of a 3D-LUT, the values ​​(10-bit values) of the input video signal assigned to the grid points, and the normalized signal values ​​for the input video signal values. For each of grid point numbers 1 to 33, the 10-bit value of the input / output video signal assigned to that grid point number corresponds, and the normalized signal values ​​when the 10-bit value is converted in a limited range and when converted in a full range are shown.

[0105] The normalized signal value for the 10-bit value of the input video signal in the limited range is calculated using equation (4). For example, when the lattice point number is 3, if the 10-bit value of this input video signal, 64, is normalized, the normalized signal value becomes 0.

[0106] Furthermore, the normalized signal value for the 10-bit value of the full-range input video signal is calculated using the above formula (3). For example, when the grid point number is 3, the 10-bit value of this input video signal, 64, is normalized to a normalized signal value of 0.06.

[0107] Here, when an input video signal is converted into an output video signal using the 3D-LUT, the input video signal is assumed to be a limited range signal (in FIG. 1, a limited range is added to the video signal input to the table conversion unit 13).

[0108] It is also assumed that the user desires to use a 3D-LUT to implement a conversion rule for converting a 0% video signal level, where the 10-bit value of the input video signal is 64, into a 100% video signal level, where the 10-bit value of the output video signal is 940, and for converting other video signal levels (video signal levels where the 10-bit value of the input video signal is other than 64) into a 0% video signal level, where the 10-bit value of the output video signal is 64.

[0109] 8 is a diagram illustrating the internal processing and output video signal when converting an input video signal using a 3D-LUT when the 10-bit value of the input video signal is 64 and its signal level is 0% video signal level, and shows an example of changes in the 10-bit value and video signal level of the input and output video signals when the ranges of the input and output video signals match and do not match the expected range. L indicates limited range, and F indicates full range.

[0110] The input video signal is a video signal to which limited range (L) information has been added, and its 10-bit value is 64, indicating that the video signal level is 0%. The range setting (limited range (L)) in the input video signal corresponds to the range type that reflects the first range conversion type in range conversion unit 12 shown in FIG. 1. This input video signal is input to table conversion unit 13 shown in FIG. 1.

[0111] The internal processing assumes that the input video signal range is limited range (L) or full range (F), and uses a 3D-LUT generated assuming that the output video signal range is limited range (L) or full range (F).

[0112] This shows that in internal processing on the input side, the normalized signal value of the input video signal can be obtained by using equation (4) or equation (3) above, which converts the 10-bit value of the video signal into a normalized signal value depending on the assumed range of the input video signal (limited range (L) or full range (F)).

[0113] If the assumed range of the input video signal is limited range (L), then using equation (4) above, 0 is obtained as the normalized signal value of the input video signal; if it is full range (F), then using equation (3) above, 0.06 is obtained as the normalized signal value of the input video signal (see *1 and *2 in Figure 8).

[0114] According to the conversion rules used by the 3D-LUT, a 0% video signal level, where the 10-bit value of the input video signal is 64, is converted to a 100% video signal level, where the 10-bit value of the output video signal is 940. Therefore, when the normalized signal value of the input video signal is 0, this normalized signal value is converted to 940 as a 10-bit value of the output video signal. Also, according to the conversion rules used by the 3D-LUT, a video signal level other than 64 as a 10-bit value of the input video signal is converted to a 0% video signal level, where the 10-bit value of the output video signal is 64. Therefore, when the normalized signal value of the input video signal is 0.06, this normalized signal value is converted to 64 as a 10-bit value of the video signal (see *3 in Figure 8).

[0115] In this case, when the normalized signal value of the input video signal is converted into the normalized signal value of the output video signal, the expected range (limited range (L) or full range (F)) and normalized signal value of the output video signal will be as shown by *4 and *5 in Figure 8.

[0116] That is, internal processing can result in either 940 being obtained as the 10-bit value of the output video signal (see (1) to (4) in FIG. 8) or 64 being obtained (see (5) to (8) in FIG. 8).

[0117] The range setting (limited range (L) or full range (F)) of the output video signal corresponds to the range type that reflects the second range conversion type in range conversion unit 14 shown in Fig. 1. When the range setting is limited range (L), it indicates that a video signal to which limited range information has been added is generated by range conversion unit 14, and when the range setting is full range (F), it indicates that a video signal to which full range information has been added is generated by range conversion unit 14.

[0118] The level and 10-bit value of the output video signal indicate the video signal level and 10-bit value of the video signal generated by the range conversion unit 14.

[0119] 8(1) shows a case where the assumed range of the input video signal is limited range (L), the assumed range of the output video signal is limited range (L), and the range type reflecting the second range conversion type is limited range (L). A video signal with a 100% video signal level, whose 10-bit value is 940, is output as is by range conversion unit 14.

[0120] 8(2) shows a case where the assumed range of the input video signal is limited range (L), the assumed range of the output video signal is limited range (L), and the range type reflecting the second range conversion type is full range (F). Range conversion unit 14 converts a video signal with a 100% video signal level, whose 10-bit value is 940, into a video signal with a 100% video signal level, whose 10-bit value is 1023, and outputs the converted video signal.

[0121] 8(3) shows a case where the assumed range of the input video signal is limited range (L), the assumed range of the output video signal is full range (F), and the range type reflecting the second range conversion type is limited range (L). Range conversion unit 14 converts a video signal with a 100% video signal level, whose 10-bit value is 940, into a video signal with a 92% video signal level, whose 10-bit value is 869, and outputs the converted video signal. For (4) to (8) in FIG. 8 as well, the video signal shown in FIG. 8 is output.

[0122] As such, if there is an error in the full range or limited range setting for each of the input video signal, the input video signal intended as input to the 3D-LUT, the output video signal intended as output from the 3D-LUT, and the output video signal, it can be seen that both the 10-bit value and video signal level of the output video signal will differ from the expected conversion result.

[0123] In (1) and (2) of Fig. 8, the range of the input video signal assumed as the input of the 3D-LUT and the range of the output video signal assumed as the output are both limited ranges and the same. Also, in (7) and (8) of Fig. 8, the range of the input video signal assumed as the input of the 3D-LUT and the range of the output video signal assumed as the output are both full ranges and the same. In this case, values ​​corresponding to the lattice point numbers are defined for the 3D-LUT, taking into account that the range of the input video signal assumed as the input and the range of the output video signal assumed as the output are the same.

[0124] 8(3) to 8(6), the range of the input video signal assumed as the input to the 3D-LUT differs from the range of the output video signal assumed as the output (if one is limited range, the other is full range). In this case, the 3D-LUT defines values ​​corresponding to the grid point numbers, taking into account the difference between the range of the input video signal assumed as the input and the range of the output video signal assumed as the output.

[0125] (Display section 16) Returning to FIGS. 1 and 2, the display unit 16 has a function of visualizing the quantitative evaluation values ​​calculated by the evaluation unit 15 and presenting them to the user.

[0126] Specifically, the display unit 16 receives the quantitative evaluation value, the range setting verification result, and the like from the evaluation unit 15 and displays them on the screen (step S207).

[0127] In addition, the display unit 16 displays on the screen the range type set in the test pattern signal generating unit 11, the first range conversion type set in the range conversion unit 12, the interpolation method type set in the table conversion unit 13, the second range conversion type set in the range conversion unit 14, and the range type set in the evaluation unit 15.

[0128] 9 is a diagram showing an example of a radar chart display of quantitative evaluation values. This radar chart shows PSNR, SSIM, and average color difference ΔE ab,mean, maximum color difference ΔE ab,max The quantitative evaluation values ​​for six items, namely, the horizontal and vertical shifts of maximum brightness, are listed in a table. The standard quantitative evaluation value is given a grade of A, and the quantitative evaluation value obtained this time by the evaluation unit 15 is given a grade of B.

[0129] From Figure 9, it can be seen that the wider the area connecting the quantitative evaluation values ​​of the grades B for each item is compared to the area connecting the standard grades A, the better the performance of grade B can be judged to be than the standard grade A, and the narrower the area is, the worse the performance can be judged to be.

[0130] The standard score A indicates the score of the quantitative evaluation values ​​of the six items when the number of grid points used in the 3D-LUT is set to 33, which is the middle value, and the type of interpolation method set in the table conversion unit 13 is set to the theoretical value of the simple cubic interpolation method.

[0131] The display unit 16 displays the quantitative evaluation values ​​input from the evaluation unit 15, such as PSNR, SSIM, and average color difference ΔE ab,mean , maximum color difference ΔE ab,max Using the horizontal and vertical deviations of maximum brightness, a radar chart as shown in FIG. 9 is generated so that the wider the range of scores, the better the performance, and this is displayed on the screen.

[0132] From the radar chart shown in FIG. 9, it can be seen that the grade B (the user-defined pattern corresponding to grade B) has better PSNR and SSIM (better image quality) than the standard grade A (the standard user-defined pattern), which are used to evaluate image quality degradation, and the maximum color difference ΔE ab,max and average color difference ΔE ab,mean It can be seen that the horizontal and vertical maximum luminance shifts used to evaluate the discontinuity of gradation are poor (poor discontinuity of gradation).

[0133] As described above, according to the video signal processing device 1 of the embodiment of the present invention, the test pattern signal generating unit 11 generates a test pattern video signal from a test pattern image based on a range type or the like preset by a user, and the range conversion unit 12 converts the range of the test pattern video signal in accordance with the first range conversion type preset by the user.

[0134] The table conversion unit 13 converts the range-converted video signal values ​​into normalized signal values ​​in accordance with the range type reflecting the first range conversion type, and converts the range-converted normalized signal values ​​of the input video signal into normalized signal values ​​of the output video signal by performing interpolation processing in accordance with the interpolation method type preset by the user using the 3D-LUT.Then, the table conversion unit 13 converts the normalized signal values ​​of the output video signal into a video signal in accordance with the range type reflecting the first range conversion type.

[0135] The range conversion unit 14 converts the range of the video signal converted by the table conversion unit 13 in accordance with a second range conversion type preset by the user.

[0136] The evaluation unit 15 generates a correct video signal from the correct image based on the range type etc. preset by the user. Then, the evaluation unit 15 compares the image of the correct video signal and the image of the video signal after range conversion (image of the conversion result) to generate a quantitative evaluation value, a range setting verification result etc. The display unit 16 displays the quantitative evaluation value, the range setting verification result etc. on the screen.

[0137] This allows us to objectively evaluate the conversion performance of 3D-LUTs used when converting video signals into video signals of different formats.

[0138] In other words, when evaluating conversion performance using a 3D-LUT, not only can the conversion performance of the 3D-LUT be quantitatively evaluated, but it can also be determined whether the 3D-LUT was generated assuming a limited range or full range as the range type of the input / output video signal. Furthermore, the effects of different interpolation processes can be evaluated by relatively comparing them with the effects of other interpolation processes, combinations of 3D-LUT grid points, etc.

[0139] Conventionally, the conversion performance of a 3D-LUT could only be evaluated subjectively, but in an embodiment of the present invention, color misalignment and discontinuity in gradation, which are difficult to confirm through subjective evaluation, can be objectively evaluated, for example, from the size and shape of the area of ​​a radar chart display.

[0140] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the technical concept thereof.

[0141] A typical computer can be used as the hardware configuration of the video signal processing device 1 according to the embodiment of the present invention. The video signal processing device 1 is configured by a computer including a CPU, a volatile storage medium such as RAM, a non-volatile storage medium such as ROM, an interface, etc.

[0142] The functions of the memory unit 10, test pattern signal generating unit 11, range conversion units 12 and 14, table conversion unit 13, evaluation unit 15 and display unit 16 provided in the video signal processing device 1 are each realized by having the CPU execute a program that describes these functions.

[0143] Furthermore, when evaluating a 3D-LUT input to the external device 2, the functions of the memory unit 10, test pattern signal generating unit 11, range conversion units 12 and 14, evaluation unit 15 and display unit 16 provided in the video signal processing device 1 are each realized by having the CPU execute a program that describes these functions.

[0144] These programs are stored in the storage medium and are read and executed by the CPU. These programs can also be stored in a storage medium such as a magnetic disk (HDD, etc.), an optical disk (CD-ROM, DVD, etc.), or a semiconductor memory (SSD, etc.) and distributed, or can be transmitted and received via a network. [Industrial Applicability]

[0145] The video signal processing device 1 according to an embodiment of the present invention is used as a pre-verification device at a content production site when using a 3D-LUT, and can improve the reliability of the 3D-LUT and devices incorporating the 3D-LUT at a production site where the 3D-LUT is used. [Explanation of symbols]

[0146] 1. Video signal processing device 2 External device 10 Storage section 11 Test pattern signal generator 12,14 Range conversion section 13 Table conversion section 15 Evaluation Section 16 Display section

Claims

1. A video signal processing device for evaluating a 3D-LUT used when converting a video signal into a video signal of a different format, a storage unit that stores a test pattern image, a correct image obtained by converting the test pattern image using a predetermined conversion algorithm, and the 3D-LUT that describes the relationship between normalized signal values ​​of input video signals and normalized signal values ​​of output video signals; a test pattern signal generating unit that reads out the test pattern image from the storage unit and generates a test pattern video signal from the test pattern image; a first range conversion unit that converts the range of the test pattern video signal generated by the test pattern signal generation unit in accordance with a first range conversion type preset by a user, and outputs the converted video signal; converting the value of the video signal into a normalized signal value of an input video signal according to a range type indicating a range type of the video signal output by the first range conversion unit; reading the 3D-LUT from the storage unit, and using the 3D-LUT to perform interpolation processing in accordance with an interpolation method type preset by a user, thereby converting the normalized signal value of the input video signal into a normalized signal value of an output video signal; a table conversion unit that converts the normalized signal value of the output video signal into a video signal value according to the range type and outputs the converted video signal; a second range conversion unit that converts the range of the video signal output by the table conversion unit in accordance with a second range conversion type preset by a user; an evaluation unit that reads the target image from the storage unit and generates an evaluation value for evaluating the 3D-LUT based on the target image and the image of the video signal converted by the second range conversion unit; A video signal processing device comprising:

2. A video signal processing device in a system including an external device that converts an input video signal using a 3D-LUT, which is a table that converts an input video signal into an output video signal of a different format, the 3D-LUT describing a relationship between a normalized signal value of the input video signal and a normalized signal value of the output video signal, and a video signal processing device that evaluates the 3D-LUT, the external device converts the value of the video signal into a normalized signal value of the input video signal according to a range type indicating a range type of the input video signal; converting the normalized signal value of the input video signal into a normalized signal value of an output video signal by performing a predetermined interpolation process using the 3D-LUT; When converting the normalized signal value of the output video signal into a video signal value according to the range type and outputting the video signal, The video signal processing device comprises: a storage unit that stores a test pattern image and a correct image obtained by converting the test pattern image using a predetermined conversion algorithm; a test pattern signal generating unit that reads out the test pattern image from the storage unit and generates a test pattern video signal from the test pattern image; a first range conversion unit that converts the range of the test pattern video signal generated by the test pattern signal generation unit in accordance with a first range conversion type preset by a user, and outputs the converted video signal to the external device; a second range conversion unit that converts the range of the video signal output by the external device in accordance with a second range conversion type preset by a user; an evaluation unit that reads the correct image from the storage unit and generates an evaluation value for evaluating the 3D-LUT based on the correct image and an image of the video signal output by the external device; A video signal processing device comprising:

3. 3. The video signal processing device according to claim 1, The range type is either a full range having a predetermined range or a limited range having a range narrower than the full range, a video signal processing device, characterized in that each of the first range conversion type and the second range conversion type is one of conversion from the full range to the limited range, conversion from the limited range to the full range, and no conversion.

4. A program for causing a computer to function as the video signal processing device according to claim 1 or 2.

Images