JP2010011091A - Digital video evaluation device and evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital video evaluation device and evaluation method which checks if there is a difference between input and output videos, a difference in video between parallel lines, a difference in video between frames, and a distortion in video, using color bar video data. <P>SOLUTION: The digital video evaluation device includes: a video data extraction section which extracts brightness values of R, G and B and pixel positions corresponding to the brightness values from color bar video data demodulated by a digital video signal output device; and a determination section which determines that the digital video is normal when a calculated value for a pixel difference for each of R, G and B, which is a difference between a sum of numbers of parallel pixels within a range of a brightness value set in advance for each of R, G and B and a pixel determination value recorded in advance in a recording section for each of R, G and B, is within a value for determining a difference between pixel input and output videos, based on the extraction results of the video data extraction section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a digital video evaluation apparatus and evaluation method for evaluating digital video.

  Conventionally, in order to evaluate the quality of an output video from a display device, humans subjectively evaluate the screen of a display device (such as a television or a monitor) that reproduces and outputs a video signal. On the other hand, video quality is evaluated based on numerical values of various data measured by the signal-to-noise power ratio (SNR), bit error rate (BER), etc. of the video signal.

  However, when a human evaluates an image, the evaluation result may vary due to subjective evaluation. In addition, when trying to objectively evaluate the video signal, there is a problem that the video can be evaluated only by SNR and BER.

  According to Patent Document 1, an inspection video transmission apparatus that transmits an MPEG stream in which inspection images are inserted at a predetermined time interval T to a digital broadcast receiving apparatus, according to this, describes an MPEG stream transmitted to the digital broadcast receiving apparatus. An inspection image of the frame is acquired in response to detection of the pulse signal and stored in the memory. If it is determined whether the image of the frame stored last time is the same as the image of the frame stored this time or not, a noise occurrence alert indicating that noise is generated in the video signal is displayed in the memory or the printout. An inspection apparatus for recording on a medium or the like has been proposed.

  In Patent Document 2, a test signal transmission unit that transmits a test signal for displaying an image to the image display device, and a first output from the video output terminal of the image display device as a result of the transmission of the test signal to the image display device. An image input unit for inputting the test image, an image capturing unit for capturing the first test image displayed on the display unit of the image display device and generating a second test image, and control for generating a test signal. In addition, there has been a proposal for automating test processing and verification processing of an image display device including a control unit that performs the pass / fail determination of the first and second test images.

Japanese Patent Application Laid-Open No. 2003-228688 discloses an operation inspection comprising sending means for sending a data stream including moving image data, a decoder board to be inspected for decoding the data stream and outputting video data, and an inspection device for inspecting the decoder board Computation means for performing predetermined computation processing on video data, storage means for storing the expected value of the computation result, and comparison means for comparing the computation result with the expected value read from the storage means And a video display system that enables video inspection of a DTV board that receives a digital broadcast, including a determination display unit that displays a pass / fail determination based on a comparison result.
JP-A-2005-340970 JP2007-184723 JP2007-288634

In view of the above circumstances, the digital video signal output device can be used to evaluate the output video of the digital video signal output device using, for example, input / output video differences, horizontal line differences, frame differences, and video distortion. An object is to provide a video evaluation apparatus and an evaluation method.

A digital video evaluation device that evaluates a video output from a digital video signal output device, which is one aspect, includes a video data extraction unit and a determination unit.
The video data extraction unit is a color in which the luminance values of RGB received by the digital video signal output device are arranged in a horizontal direction so that the number of horizontal pixels is equalized by combining the minimum value and the maximum value. The bar video is demodulated to generate color bar video data, and a luminance value and a pixel position corresponding to the luminance value are extracted for each RGB. The determination unit is a difference between the total number of the horizontal pixels in the luminance value range set in advance for each RGB and the pixel determination value recorded in the recording unit in advance for each RGB based on the extraction result of the video data extraction unit. When the pixel difference calculation value for each RGB is within the range of the pixel input / output video difference determination value recorded in advance in the recording unit, it is determined to be normal.

  By configuring as described above, by confirming the difference between input and output images, the difference between horizontal lines, the difference between frames, and the confirmation of image distortion that have been performed in the subjective evaluation until now by confirming with the digital image signal Objective evaluation can be performed. The amount of sampling required for evaluation can also be performed on several horizontal lines, which can be performed at high speed.

  The determination unit corresponds to the luminance value within a luminance value range set in advance for each RGB based on the luminance value of one horizontal line extracted from one frame by the video data extracting unit and the pixel position. The total number of horizontal pixels to be calculated is calculated. The pixel difference calculation value for each RGB, which is the difference between the total number of pixels and the pixel determination value recorded in advance in the recording unit for each RGB, is the pixel input / output video difference determination value recorded in the recording unit in advance. Determine if it is within range. When all of RGB are within the range of the pixel input / output video difference determination value, it is determined to be normal.

  In addition, the determination unit determines the luminance value for each RGB based on the luminance value and the pixel position of the first line and the second line that are two horizontal lines extracted from one frame by the video data extraction unit. Mode is calculated, a mode-to-line mode value difference calculation value, which is a difference between the mode values of the first line and the second line, is calculated for each RGB, and the recording unit is previously recorded for each RGB. It is determined whether it is within the range of the mode value difference determination value recorded between lines. Further, a line-to-line pixel difference calculation value that is a difference in the number of pixels corresponding to the mode value of the first line and the second line is calculated for each RGB, and the line recorded in advance in the recording unit for each RGB. It is determined whether it is within the range of the inter-pixel difference determination value. It is determined to be normal when all of RGB are within the range of the mode difference determination value between the lines and within the range of the pixel input / output video difference determination value.

  In addition, the determination unit extracts two adjacent horizontal lines while shifting the first horizontal line to the last horizontal line of the frame one line at a time by the video data extraction unit from one frame. The inter-line pixel difference calculation value is calculated for each RGB based on all the luminance values and the pixel positions of the first line and the second line extracted up to the final horizontal line, and the inter-line intervals for each RGB. The maximum value of the pixel difference calculation value is calculated, and when it is within the range of the interline pixel difference determination value, it is determined to be normal.

Further, the determination unit extracts a horizontal line from each of the two frames by the video data extraction unit, and determines the first line and the second line.
The determination unit calculates a differential value for the luminance value for each RGB based on the luminance value and the pixel position of the color bar video data extracted by the video data extraction unit, It is determined to be normal when it is within the range of the differential determination value recorded in the recording unit.

  By using the color bar video data, the output video of the digital video signal output device can be evaluated by, for example, input / output video differences, horizontal line differences, frame differences, and video distortion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Example 1
FIG. 1 is a diagram showing the configuration of an apparatus for evaluating digital video. The apparatus for evaluating digital video includes a signal generator 1, a digital video signal output device 2, a digital evaluation system 3, and a PC 4. The digital video signal output device 2 includes an RF unit 5 (radio frequency), an OFDM unit 6 (Orthogonal Frequency Division Multiplexing), and a multimedia chip 7. The digital evaluation system 3 includes a display device 8 and a digital video evaluation device 9.

  The signal generator 1 generates a transmission signal based on predetermined color bar video data, and transfers the transmission signal to the digital video signal output device 2 wirelessly or by wire. For example, the transmission signal is a signal obtained by modulating digital video data by a system such as terrestrial digital broadcasting, BS digital broadcasting, or one-segment broadcasting.

  The digital video signal output device 2 is a receiving device that receives and demodulates broadcast waves such as terrestrial digital broadcast, BS digital broadcast, and one-segment broadcast by the RF unit 5, the OFDM unit 6, the multimedia chip 7, and the like. The digital video signal output device 2 is incorporated in a television, a mobile phone, or the like.

  The digital evaluation system 3 evaluates the digital video (output video) demodulated by the digital video signal output device 2. The display device 8 of the digital evaluation system 3 displays the digital video demodulated by the digital video signal output device 2. The digital video evaluation device 9 of the digital evaluation system 3 measures color input / output video differences, horizontal line differences, frame differences, video distortion, and the like by using color bar video data.

  The PC 4 acquires the result determined by the digital video evaluation device 9 and displays the determination result on the monitor of the PC 4. Further, the PC 4 performs control for adjusting each part of the digital video signal output device 2 based on the determination result.

  FIG. 2 is a block diagram showing the configuration of the digital video evaluation device 9. The digital video evaluation device 9 includes an input interface unit 21, a video evaluation unit 22, a recording unit 23, and an output interface unit 24. For example, the digital video evaluation device 9 may use a programmable device such as a field programmable gate array (FPGA) or a complex programmable logic device (CPLD), or may use a CPU.

The input interface unit 21 acquires the digital video data demodulated by the digital video signal output device 2 and transfers it to the video evaluation unit 22.
The video evaluation unit 22 includes a video data extraction unit 25 and a determination unit 26. The video data extraction unit 25 extracts data necessary for evaluation from the digital video data demodulated by the digital video signal output device 2 and transfers the data to the determination unit 26. The determination unit 26 determines input / output video differences, horizontal line differences, frame differences, video distortion, and the like based on the extracted data.

The recording unit 23 records determination data used in each measurement. The same color bar video data generated by the signal generator 1 is recorded.
The output interface unit 24 acquires the determination result of the video evaluation unit 22, and outputs the determination result in a preset data format (RS232C, USB, etc.).

  FIG. 3 is a diagram showing the configuration of the color bar video data. In FIG. 3B, eight colors of “white”, “yellow”, “cyan”, “green”, “magenta”, “red”, “blue”, and “black” are arranged in order so that the number of pixels in the horizontal direction becomes equal. In addition, the luminance values of “R (Red; Red)”, “G (Green; Green)”, and “B (Blue; Blue)” are “0” (minimum value) or “255” (maximum value). Either can be represented. As shown in FIG. 3A, the luminance values of “R”, “G”, and “B” of “white” are each “255”, and the luminance values of “black” are all “0”. The luminance values of the colors “R”, “G”, and “B” in the meantime are represented by either “0” or “255”. In this example, each frame is composed of 320 (horizontal) × 240 (vertical), and the luminance value is represented by 8 bits. Further, the color of the horizontal pixel changes every 40 pixels.

A method for checking the difference between input and output video will be described.
FIG. 4 is a diagram showing the principle when confirming the difference between input and output images. FIG. 4A is a diagram showing a histogram of video data in a normal state. 4B to 4D are diagrams showing histograms of video data at the time of deterioration. E in FIG. 4 is a diagram illustrating a determination range for determining whether or not the deterioration has occurred.

  The digital video data normally demodulated by the digital video signal output device 2 becomes the same data as the color bar video data. When one horizontal line is arbitrarily selected from the demodulated digital video data, the sum of horizontal pixels of “R”, “G”, and “B” luminance values “255” in each line is “160”. . That is, if it is normal, the luminance value and the number of pixels of the demodulated digital video data become a histogram as shown in FIG.

  When the digital video signal output device 2 is not normally demodulated, for example, the digital video data is as shown in B to D of FIG. In FIG. 4B, since there is a value other than “255” in the luminance value of one line “R” in the horizontal direction of the demodulated digital video data, the sum of the horizontal pixels of the luminance value “255” becomes “160”. It is a histogram when it does not become. In FIG. 4C, for example, the luminance value of “R” of one line in the horizontal direction of the demodulated digital video data is “255” and the total number of horizontal pixels is “160”, but “G” “B”. Is a histogram when the sum of horizontal pixels is “160” but the luminance value is not “255”. FIG. 4D is a histogram when the luminance value of “R” of one line in the horizontal direction of demodulated digital video data is “200” and the total number of horizontal pixels is “160”, for example.

  In order to determine whether or not the digital video signal output device 2 has normally demodulated, for example, the luminance values of “R”, “G”, and “B” in one horizontal line as shown in the histogram shown in E of FIG. A determination is made by comparing the total number of pixels measured within 100% to 95% of “255” with a preset value. For example, it is determined whether or not the total number of pixels is within 100% to 95% of a preset value “160”. If the determined result is within the range, it is determined to be normal.

FIG. 5 is a flowchart showing an operation for confirming a difference between input and output images.
For example, as a condition for video evaluation, a color bar is input as a still image for an input image, and an 8-color bar (see FIG. 3) is output as a test pattern. The digital video data which is the output signal of the digital video signal output device 2 is taken in and processed, and the result is output to the PC 4. In this example, the output image of the digital video signal output device 2 is 320 × 240, 15 fps.

  In step S1, digital video data (frame data) is captured. The demodulated digital video data is acquired from the input interface unit 21 of the digital video evaluation device 9.

  In step S2, video data for one line is extracted from the digital video data. The video data extraction unit 25 of the video evaluation unit 22 extracts video data for one line from the digital video data. For example, as shown in the video data for one line shown in FIG. 5, luminance values “0” to “255” corresponding to the pixel coordinates (m, n) are extracted for each of “R”, “G”, and “B”. . Note that m is the pixel position in the horizontal direction, and n is the pixel position in the vertical direction.

  For example, “(1, n) 255” “(2, n) 255” “(3, n) 255”... “(320, n) 0” in order from the first column of the n-th row for “R”. Then, similarly to “R”, the luminance values “0” to “255” corresponding to the pixel coordinates (m, n) are extracted for “G” and “B”.

  In step S3, the difference between the digital video data and the determination data is calculated. The determination unit 26 calculates the total number of pixels in each luminance value range for each of “R”, “G”, and “B” from the digital video data for one line, and the calculation result is the range described in E of FIG. In order to determine whether it is within the range, the difference between the determination data shown in FIG. 5 recorded in the recording unit 23 and the pixel determination value is calculated. The difference is calculated by Equation 1.

“R” pixel difference calculation value =
Total number of pixels in luminance value range of “R” −pixel determination value of “R” Pixel difference calculated value of “G” =
Total number of pixels in the luminance value range of “G” −pixel determination value of “G” Equation 1
Calculated pixel difference value of “B” =
Total number of pixels within the luminance value range of “B” −pixel determination value of “B”

For example, “242” is set in the luminance value range to determine whether it is within 100% to 95% of “255”, and the sum of the pixels within “255” to “242” is calculated. In addition, “152” corresponding to a value of 95% of “160” is set in advance as the “pixel determination value”. If the total number of pixels in the measured luminance value range is “155”, the calculated pixel difference is “155” − “152” = “3”.

  In step S4, it is determined whether the difference between the input and output video data of the digital video signal output device 2 is within a preset range. If it is within the range, the process proceeds to step S5. Transition. For example, the determination unit 26 stores the pixel input / output video difference determination value for each of “R”, “G”, and “B” recorded in advance in the recording unit 23, the pixel difference calculation value “R” calculated by Equation 1, and “G”. The pixel difference calculated value and the pixel difference calculated value of “B” are respectively compared to determine whether or not it is normal. Further, the determination unit 26 transfers the determination result to the output interface unit 24.

  For example, if any of “R”, “G”, and “B” is described, if the pixel input / output video difference determination value is “13” and the pixel difference calculated value is “3”, the pixel difference calculated value <pixel It is determined that the relationship between the input / output video difference determination values is established and is normal.

  In step S5, when the determination result is normal, the user is notified based on the determination result. For example, “OK” is displayed on the monitor of the PC 4. If the determination result is not normal in step S6, the user is notified based on the determination result. For example, “NG” is displayed on the monitor of the PC 4 or the like.

By measuring as described above, the difference between input and output images can be confirmed, and the time required for image evaluation can be shortened.
In the first embodiment, the input / output video difference confirmation test is performed for only one horizontal line. However, a plurality of horizontal lines may be tested, and the test results of the plurality of arbitrarily selected horizontal lines are all normal. If there is, it is possible to pass the input / output video difference confirmation test.
(Example 2)
In the second embodiment, confirmation of a difference between horizontal lines will be described.

  FIG. 6 is a diagram illustrating a principle for confirming a difference between horizontal lines. FIG. 6A is a diagram showing a histogram of video data in a normal state. FIG. 6B is a diagram showing a histogram of video data at the time of deterioration.

  For example, as a condition for video evaluation, a color bar is input as a still image for an input image, and eight color bars are output as a test pattern. The digital video data which is the output signal of the digital video signal output device 2 is taken in and processed, and the result is output to the PC 4. In this example, the output image of the digital video signal output device 2 is 320 × 240, 15 fps.

  The histogram showing the first normal line in FIG. 6A is created by the method described in the first embodiment. The histogram indicating the second normal line in FIG. 6A is also created by the method described in the first embodiment, and is a histogram of horizontal lines different from the normal first line in FIG. 6A. . In the histogram representing the comparison between the first line and the second line in FIG. 6A, it is determined that both the first line and the second line in the normal state are normal. The number of pixels with respect to the luminance value of the line of FIG. That is, there is no significant difference in the number of pixels with respect to the luminance value between horizontal lines.

  FIG. 6B shows a case where deterioration occurs in the second line. The luminance value of “R” and the maximum number of pixels corresponding to it are shifted from the luminance value of “G” and “B” and the maximum number of pixels corresponding thereto. ing. When “R” of the first line and “R” of the second line are compared, a pixel difference is generated between the horizontal lines because the second line is deteriorated.

FIG. 7 is a flowchart showing an operation for confirming a difference between horizontal lines.
For example, the input image is input with a color bar as a still image, and the digital video signal output device 2 outputs eight color bars as a test pattern. The digital video data which is the output signal of the digital video signal output device 2 is taken in and processed, and the result is output to the PC 4. In this example, the output image of the digital video signal output device 2 is 320 × 240, 15 fps.

  In step S71, digital video data (frame data) is captured. The demodulated digital video data is acquired from the input interface unit 21 of the digital video evaluation device 9.

In step S72, video data of two different horizontal lines are extracted from the digital video data. As in the first embodiment, the video data extraction unit 25 of the video evaluation unit 22 extracts video data for two horizontal lines from the digital video data. Here, the two horizontal lines are the first line and the second line, respectively, the digital video data of the first line is the first video data, and the digital video data of the second line is the second video data. Call.

  In step S73, the difference between the first video data and the second video data is calculated. The determination unit 26 detects the maximum value of each luminance value (the highest frequency of the signal level) for each of “R”, “G”, and “B” from the first video data and the second video data, and the detected maximum The number of pixels with respect to the most frequent signal level is detected. The horizontal line difference is calculated by comparing the calculation results. The difference is calculated by Equations 2 and 3.

Calculated value of mode difference between lines of “R” =
Mode of first video data of “R” —Mode of second video data of “R”

Calculated value of mode difference between lines of “G” =
Mode of first video data of “G” Formula 2
-Mode of the second video data of "G"

Calculated value of mode difference between lines of “B” =
Mode of the first video data of “B” —Mode of the second video data of “B”


Calculated value of pixel difference between lines of “R” =
The number of pixels of the mode value of the first video data of “R” —The number of pixels of the mode value of the second video data of “R”

Calculated pixel difference between lines of “G” =
Number of pixels of the mode value of the first video data of “G” Equation 3
-Mode number of pixels of the second video data of "G"

Calculated pixel difference between lines of “B” =
The number of mode pixels of the first video data of “B” —the number of pixels of the mode value of the second video data of “B”

In step S74, it is determined whether the difference between the first video data and the second video data is within a preset range. If it is within the range, the process proceeds to step S75, and if it is out of the range, the process proceeds to step S76. To do. For example, the determination unit 26 calculates the inter-line pixel difference determination value recorded in advance in the recording unit 23, the calculated inter-line mode value difference between “R”, “G”, and “B” calculated by Equations 2 and 3, and the inter-line pixel. The difference calculation values are respectively compared, and the relationship between the line mode value difference calculation value and the line mode value difference determination value is between the line mode value difference calculation value <the line mode value difference determination value, Further, if the relationship between the inter-line pixel difference calculated value and the inter-line pixel difference determination value satisfies the relationship between the inter-line pixel difference calculated value <the inter-line pixel difference determination value, it is determined to be normal. Further, the determination unit 26 transfers the determination result to the output interface unit 24.

  For example, when the calculated mode difference value between the lines is “3”, the mode difference judgment values between all the lines “R”, “G”, and “B” are within the range of “10”. When the pixel difference calculation value is “13”, if all the inter-line pixel difference determination values of “R”, “G”, and “B” are within the range of “13”, it is determined as normal.

  If the determination result is normal in step S75, the user is notified based on the determination result. For example, “OK” is displayed on the monitor of the PC 4. If the determination result is not normal in step S76, the user is notified based on the determination result. For example, “NG” is displayed on the monitor of the PC 4 or the like.

By measuring as described above, it is possible to confirm the difference in the video between the horizontal lines, and to shorten the video evaluation time.
(Modification)
A modification of the second embodiment will be described. In the second embodiment, the video is evaluated by comparing two horizontal lines. However, deterioration between adjacent horizontal lines (deterioration such as a horizontal stripe pattern) may be evaluated.

FIG. 8 is a flowchart showing an operation for confirming a difference from an adjacent horizontal line.
In step S81, the first video data is extracted from the horizontal line at the head of the frame in the same manner as in S2. For example, the video data extraction unit 25 extracts the first video data from the first horizontal line of the digital video data (frame data).

In step S82, the second video data is extracted from the second horizontal line in the same manner as in S2. Second video data is extracted from the next horizontal line (second row).
In steps S83 and S84, the processing performed in steps S73 and S74 is executed. If the determination result of the first video data and the second video data is normal in S84, the process proceeds to step S87, and if not normal, the process proceeds to step S85.

In step S85, the maximum value (mode value) of the inter-line pixel difference calculation values for each of “R”, “G”, and “B” is recorded in the recording unit 23.
In step S86, it is determined whether the interline pixel difference calculation value has been calculated up to the horizontal line of the last row. If it is the last, it moves to step S88, and if it is not the last, it moves to step S87.

  In step S87, the current horizontal line is changed to the next horizontal line. That is, the line is shifted by one line and the process proceeds to step S81. Then, the processing is continued until the last line of the frame while changing the first video data and the second video data in the same manner as the above processing.

Note that the second video data may be replaced with the first video data, the second video data may be extracted from the third row, and the processes of steps S73 and S74 may be performed.
In step S88, the difference between the maximum value of the inter-line pixel difference calculation values recorded in the recording unit 23 for each of “R”, “G”, and “B” and the preset pixel frequency determination value is calculated and within the range. If it is out of the range, the process proceeds to step S810, and if within the range, the process proceeds to step S89.

  If the determination result is normal in step S89, the user is notified based on the determination result. For example, “OK” is displayed on the monitor of the PC 4. If the determination result is not normal in step S810, the user is notified based on the determination result. For example, “NG” is displayed on the monitor of the PC 4 or the like.

The figure shown in FIG. 9 is a figure which shows the result of confirming the difference between horizontal lines.
It is a figure which shows the result of confirming the difference between horizontal lines. The vertical axis indicates the signal level (mode), and the horizontal axis indicates the line number (S, T: integer) of the horizontal line.

By measuring as described above, it is possible to confirm the difference in the video between the horizontal lines, and to shorten the video evaluation time.
(Example 3)
FIG. 10 is a flowchart showing an operation for confirming a difference between frames.

In the second embodiment, confirmation of a difference between horizontal lines will be described.
In step S91, two digital video data (frame data) are captured. The demodulated digital video data is acquired from the input interface unit 21 of the digital video evaluation device 9.

  In step S92, horizontal line video data is arbitrarily extracted from each of the two digital video data. For example, horizontal lines at the same position may be acquired, or horizontal lines at different positions may be acquired. The video data extraction unit 25 of the video evaluation unit 22 performs a first operation for each of “R”, “G”, and “B” for one line from each digital video data (first digital video data, second digital video data). Video data and third video data are extracted. Here, the two horizontal lines are the first line and the third line, respectively, the digital video data of the first line is the first video data, and the digital video data of the third line is the third video data. Call.

  In step S93, the difference between the first video data and the third video data is calculated. The determination unit 26 detects the maximum value of each luminance value (the highest frequency of the signal level) for each of “R”, “G”, and “B” from the first video data and the third video data, and the detected maximum The number of pixels with respect to the most frequent signal level is detected. The horizontal line difference is calculated by comparing the calculation results. The difference is calculated according to Equation 4.

Calculated value of inter-frame pixel difference of “R” =
The number of pixels of the mode value of the first video data of “R” —the number of pixels of the mode value of the third video data of “R”

Calculated value of inter-frame pixel difference of “G” =
Number of pixels of the mode value of the first video data of “G” Equation 4
-The number of pixels of the mode of the third video data of "G"

Calculated value of inter-frame pixel difference of “B” =
The number of pixels of the mode value of the first video data of “B” —The number of pixels of the mode value of the third video data of “B”

In step S94, it is determined whether the difference between the first video data and the third video data is within a preset range. If it is within the range, the process proceeds to step S95, and if it is out of the range, the process proceeds to step S96. To do. For example, the determination unit 26 compares the inter-frame pixel difference determination value recorded in advance in the recording unit 23 with the inter-frame pixel difference calculation values of “R”, “G”, and “B” calculated by Expression 4, respectively. If the relationship between the calculated difference value and the inter-frame pixel difference determination value satisfies the relationship of inter-frame pixel difference calculated value <inter-frame pixel difference determination value, it is determined to be normal. Further, the determination unit 26 transfers the determination result to the output interface unit 24.

For example, when the inter-frame pixel difference calculation value is “13”, if all the inter-frame pixel difference determination values of “R”, “G”, and “B” are within the range of “13”, it is determined to be normal.
If the determination result is normal in step S95, the user is notified based on the determination result. For example, “OK” is displayed on the monitor of the PC 4. If the determination result is not normal in step S96, the user is notified based on the determination result. For example, “NG” is displayed on the monitor of the PC 4 or the like. Note that frames with differences may be output.

By measuring as described above, it is possible to check the difference in video between frames, and to shorten the video evaluation time.
Example 4
In Example 4, it is confirmed that there is no distortion in the vertical direction in the output image. A differential value (difference between adjacent levels) is obtained for each line of one frame, and the degree of distortion is measured.

  FIG. 11 is a diagram illustrating the principle of confirming the video distortion in the vertical direction. FIG. 11A is a diagram showing video data of a color bar in a normal state. B of FIG. 11 is a diagram showing the signal level of the video data at the normal time. C in FIG. 11 is a diagram illustrating a differential result of “R” in a normal state. D of FIG. 11 is a diagram showing a differential result of “R” at the time of deterioration. FIG. 12 is a flowchart showing an operation for checking video distortion.

The evaluation of the image distortion in the vertical direction will be described with reference to FIGS.
In step S111, digital video data (frame data) is captured. The demodulated digital video data is acquired from the input interface unit 21 of the digital video evaluation device 9.

  In step S112, horizontal line video data is extracted from the digital video data. The video data extraction unit 25 of the video evaluation unit 22 extracts video data for one line for each of “R”, “G”, and “B”. Since the extracted video data is obtained by demodulating the color bar video data shown in FIG. 3, it can be expressed as shown in FIG. Moreover, if A of FIG. 11 is shown by a signal level and a pixel position, it can show like B of FIG.

  In step S113, the video data shown in FIG. 11B is differentiated to calculate a differential value. When differentiation is performed, the difference value increases because the change is large at the portion where the luminance value “255” changes from “255” within the broken line range to “0”. That is, as shown in FIG. 11C, the differential value of “R” at the “change portion” becomes larger than the differential values at other pixel positions.

  In step S114, the differential value at the color boundary point and the differential determination value are compared to determine whether they are within a preset range. If it is within the range, the process proceeds to step S115, and if it is out of the range, the process proceeds to step S116. For example, the determination unit 26 compares the differential determination value recorded in advance in the recording unit 23 with the differential value at each color boundary of “R”, “G”, and “B”, and determines the difference between the differential value and the differential determination value. If the relationship of differential value <differential determination value is satisfied, it is determined to be normal. Further, the determination unit 26 transfers the determination result to the output interface unit 24. For example, a range of ± 5% may be set around the color boundary point, and the differential value of the range may be added and compared with the differential determination value.

For example, in the case of “R”, the differential values at “80”, “160”, and “240” that are the color boundaries of “R” are compared with the differential determination values to determine whether or not they are normal.
If the determination result is normal in step S115, the user is notified based on the determination result. For example, “OK” is displayed on the monitor of the PC 4. If the determination result is not normal in step S116, the user is notified based on the determination result. For example, “NG” is displayed on the monitor of the PC 4 or the like.

With the above configuration, it can be confirmed that there is no distortion in the vertical direction in the output image, and the video evaluation time can be shortened.
In addition, you may measure all combining the Examples 1-4 described above.

  The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.

It is a figure which shows the structure of the apparatus which evaluates a digital image. It is a block diagram which shows the structure of a digital video evaluation apparatus. It is a figure which shows the structure of a color bar image | video. It is a figure which shows the principle which confirms the difference of an input-output video. A is a diagram showing a histogram of video data in a normal state. B is a diagram showing a histogram of video data at the time of deterioration. C is a diagram showing a determination range for determining deterioration. It is a flowchart which shows the operation | movement which confirms the difference of an input-output video. It is a figure which shows the principle which confirms the difference between horizontal lines. A is a diagram showing a histogram of video data in a normal state. B is a diagram showing a histogram of video data at the time of deterioration. It is a flowchart which shows the operation | movement which confirms the difference between horizontal lines. It is a flowchart which shows the operation | movement which confirms the difference with an adjacent horizontal line. It is a figure which shows the result of confirming the difference between horizontal lines. It is a flowchart which shows the operation | movement which confirms the difference between frames. It is a figure which shows the principle which confirms the image distortion of a perpendicular direction. A is a diagram illustrating video data of a color bar in a normal state. B is a diagram showing the signal level of the video data at the normal time. C is a diagram showing a differential result of “R” in a normal state. D is a diagram showing a differential result of “R” at the time of deterioration. It is a flowchart which shows the operation | movement which confirms an image distortion.

Explanation of symbols

1 signal generator,
2 Digital video signal output device,
3 Digital evaluation system,
4 PC,
5 RF section,
6 OFDM part,
7 Multimedia chip,
8 display device,
9 Digital video evaluation device,
21 Input interface part,
22 Video evaluation department,
23 recording section,
24 output interface section,
25 Video data extraction unit,
26 determination unit,

Claims (7)

A digital video evaluation device for evaluating a video output from a digital video signal output device,
The digital video signal output device demodulates a color bar video in which the luminance values of RGB received by the combination of minimum and maximum values are horizontally arranged so that the number of horizontal pixels is uniform. A video data extraction unit that generates color bar video data and extracts a luminance value and a pixel position corresponding to the luminance value for each RGB;
Based on the extraction result of the video data extraction unit, a pixel for each RGB that is a difference between the total number of the horizontal pixels within a luminance value range set in advance for each RGB and a pixel determination value recorded in advance in the recording unit for each RGB A determination unit that determines that the difference calculation value is normal when it is within a range of a pixel input / output video difference determination value recorded in advance in the recording unit;
A digital video evaluation apparatus comprising: The determination unit
The sum of the number of horizontal pixels corresponding to the luminance value within a luminance value range preset for each RGB based on the luminance value and the pixel position of one horizontal line extracted by the video data extraction unit from one frame And whether the pixel difference calculation value for each RGB, which is the difference between the pixel determination value recorded in advance in the recording unit for each RGB, is within the range of the pixel input / output video difference determination value recorded in the recording unit in advance. The digital video evaluation apparatus according to claim 1, wherein the digital video evaluation apparatus determines that it is normal when all of RGB are within the range of the pixel input / output video difference determination value. The determination unit
The mode value of the luminance value is calculated for each RGB based on the luminance value and the pixel position of the first and second lines, which are two horizontal lines extracted from one frame by the video data extraction unit. The inter-line mode value difference calculated value, which is the mode difference between the first line and the second line, is calculated for each RGB, and the inter-line mode recorded in advance in the recording unit for each RGB. While judging whether it is within the range of the value difference judgment value,
A line-to-line pixel difference calculation value that is a difference in the number of pixels corresponding to the mode value of the first line and the second line is calculated for each RGB, and between the lines recorded in advance in the recording unit for each RGB Judge whether it is within the range of pixel difference judgment value,
3. The method according to claim 1, wherein, in all of RGB, it is within the range of the mode value difference determination value between lines, and is determined to be normal when it is within the range of the pixel input / output video difference determination value. Digital video evaluation device. The determination unit
The video data extraction unit extracts one adjacent horizontal line from one frame while shifting from the first horizontal line to the last horizontal line by one line,
Calculating the inter-line pixel difference calculation value for each RGB based on all the luminance values and the pixel positions of the first line and the second line extracted from the leading horizontal line to the final horizontal line;
4. The digital image evaluation according to claim 3, wherein a maximum value of the inter-line pixel difference calculation value is calculated for each RGB, and is determined to be normal when it is within the range of the inter-line pixel difference determination value. apparatus. The determination unit
4. The digital video according to claim 3, wherein two horizontal lines obtained by extracting the horizontal lines from the two frames by the video data extraction unit are determined as the first line and the second line. 5. Evaluation device. The determination unit
Based on the luminance value and the pixel position of the color bar video data extracted by the video data extraction unit, a differential value is calculated for the luminance value for each RGB, and a differential determination recorded in advance in the recording unit for each RGB The digital video evaluation apparatus according to claim 1, wherein the digital video evaluation apparatus is determined to be normal when the value is within a range of values. A digital video evaluation method for evaluating a video output from a digital video signal output device,
The digital video signal output device receives a color bar image obtained by demodulating a color bar image in which the RGB luminance values are arranged in the horizontal direction so that the number of horizontal pixels is equal to the minimum value or the maximum value. Video data extraction processing for generating bar video data and extracting a luminance value and a pixel position corresponding to the luminance value for each RGB;
Based on the extraction result, the difference between the total number of pixels within the luminance value range set in advance for each RGB and the pixel determination value recorded in advance in the recording unit for each RGB is calculated, and the pixel difference calculated value for each RGB is calculated. A determination process for calculating and determining that the pixel difference calculation value for each RGB is normal when the pixel difference calculation value is within the range of the pixel input / output video difference determination value recorded in advance in the recording unit for each RGB;
A digital video evaluation method comprising: