JP2007194741A - Flicker video detection apparatus, flicker video detection program, video display apparatus, number of improper luminance pixel calculation method, and flicker detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flicker video detection apparatus capable of detecting intervals of video capable of causing photosensitive seizure under an environment where a viewer actually views video. <P>SOLUTION: The flicker video detection apparatus 6 includes a luminance value specifying means 62 for specifying a luminance value corresponding to a pixel value; a number of criterion pixel calculation means 64 for calculating number of pixels by a reference ratio, with respect to the size of a display region in an actual visual distance as number of criterion pixels; a number of large luminance difference pixel accumulation means 66 for accumulating the number of pixels the difference of the luminance values from those of pixels, corresponding to an adjacent frame of which is a reference luminance difference or larger, as number of large luminance difference pixels; an improper frame discrimination means 67 for discriminating whether the concerned frame causes visually improper luminance changes, on the basis of the number of large luminance difference pixels and the number of the criterion pixels; and an improper interval detection means 68 for detecting the time interval of video, capable of causing photosensitive seizure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flicker video detection device that detects a video that may cause a photosensitive seizure, a program thereof, and a video display device.

In recent years, guidelines have been established for viewers who have watched TV programs to produce videos that do not cause light-sensitive seizures, starting with problems such as convulsions and feeling sick. Detection devices have been developed that detect images that can cause photosensitive seizures.
For example, the 2001 ITC Guidelines (“ITC Guidance Note for Licensees on Flashing Image and Regular Patterns in Television”, 1994, 1998, 2001-2002) established by the Independent Television Commission (ITC) in the UK As a standard, an apparatus (Harding FPA: The Harding Flash and Pattern Analyzer; hereinafter referred to as a harding machine) that detects a video that may cause a photosensitive seizure has been developed (see Non-Patent Document 1).

In addition, for example, a device that detects video that may cause light-sensitive seizures based on guidelines established by the Japan Broadcasting Corporation and the Japan Private Broadcasting Corporation (“Guidelines on video techniques such as animation”, 1998). (Reference measuring instrument) has been developed (see Non-Patent Document 2).
The harding machine and the reference measuring instrument detect blinking (brightness flicker) or blinking red (red flicker) more than three times per second while compensating for motion.
In addition to these detection devices, a video analysis system that analyzes flicker duration in video, frequency components, and the like is disclosed (see Patent Document 1).

In February 2005, ITU-R (International Telecommunication Union-Radiocommunication Sector) established ITU-R Recommendation BT. 1702 was established. In this recommendation, although not specified in the text, as an appendix, the flashing luminance difference is 20 cd / m ² (20 candela per square meter) or more, and the area of the flashing area is 25% of the entire screen. It is said that there is a high possibility that a light-sensitive seizure will be caused when flashing exceeding 3 times occurs per second or more (6 times as the number of luminance changes).
“Harding FPA website”, [online], [searched on January 11, 2006], Internet <http://www.hardingfpa.co.uk> Emoto, Otsuka, Yamaga, Uehara, Iguchi, Ito, Fujii, “Development of“ Reference Instrument ”for Guidelines for Animation Programs”, IEICE Technical Report, 22, No. 40, pp. 1-6 (1998) JP-A-11-295360 (paragraphs 0013 to 0043)

The ITC guidelines and ITU-R recommendation BT. In order to determine whether or not the video is a video that is highly likely to cause a light-sensitive seizure according to 1702, whether or not the luminance difference between pixels at the same position in adjacent frames is 20 cd / m ² or more. It is necessary to determine whether or not an area having a luminance difference of 20 cd / m ² or more exceeds 25% of the screen.

In determining whether the luminance difference between the pixels at the same position in the frame is 20 cd / m ² or more, the conventional detection device uses a standard display with a white maximum luminance of 200 cd / m ² and a gamma value of “2.2”. Assuming that the luminance difference is determined at the level of the video signal. However, in recent years, various display devices such as a plasma display and a liquid crystal television are used for the display. These display devices do not necessarily have the same maximum brightness and gamma value as the standard display. For this reason, even in a video in which the luminance difference is determined to be less than 20 cd / m ² in the conventional inspection apparatus, in an actual viewing situation, the image may be ²⁰ cd / m ² or more, and the photosensitive seizure There is a problem that can cause.

Further, in determining whether or not an area having a luminance difference of 20 cd / m ² or more exceeds 25% of the screen, the conventional detection device is a display device having a diagonal size of 25 inches and a viewing distance of 2 m. Judgment is being made. On the other hand, the size of the blinking region that causes a photosensitive seizure is said to be determined by the number of human photoreceptor cells that the blinking light stimulates. In other words, the size of the blinking region that causes a light-sensitive seizure is not determined by the size of the physical blinking region, but by the size of the angle formed by the blinking region from the place where the viewer is viewing. There is a need. The size of the angle formed by the blinking area from the place where the viewer is viewing varies depending on the size of the display area of the display device and the viewing distance. For this reason, in a conventional inspection apparatus, even in a video in which an area with a luminance difference of 20 cd / m ² or more is determined to be less than 25% of the screen, the viewer can watch in an actual viewing situation. There is a problem that a light-sensitive seizure may be caused because the angle of the blinking area is different from the place where it is located.

  The present invention has been made in view of the above problems, and is a flicker video capable of detecting a video that may cause a light-sensitive seizure in an environment where a viewer actually views the video. It is an object of the present invention to provide a detection device, a flicker video detection program, a video display device, an inappropriate luminance pixel number calculation method, and a flicker detection method.

  The present invention has been developed to achieve the above object. First, the flicker image detection apparatus according to claim 1 is configured to detect an inappropriate standard predetermined as a visually inappropriate luminance change, Flicker for detecting a section of a video that may cause a light-sensitive seizure from the video displayed on the video display device based on the luminance characteristics of the video display device that is a viewing environment, the size of the display area, and the viewing distance. The video detection apparatus includes a luminance value specifying unit, a determination reference pixel number calculating unit, a large luminance difference pixel number accumulating unit, an inappropriate frame determining unit, and an inappropriate section detecting unit.

  In such a configuration, the flicker video detection device specifies the luminance value corresponding to the pixel value based on the specific luminance characteristics of the video display device by the luminance value specifying means. This luminance characteristic is, for example, a maximum luminance value or a gamma value. As a result, the pixel value of each pixel in the display area when displaying the video is associated with the actual luminance value.

  Further, the flicker video detection device uses the determination reference pixel number calculation unit to determine whether the reference is an inappropriate reference, the reference viewing distance, the size of the reference display area, and the luminance between adjacent frames with respect to the size of the reference display area. Based on the reference ratio of the pixels whose difference is greater than or equal to the reference luminance difference, the number of pixels that becomes the reference ratio with respect to the size of the display area of the video display device at the actual viewing distance is calculated as the determination reference pixel number. As a result, these standards are converted into standards corresponding to the actual viewing environment. Note that the standard viewing distance, the size of the standard display area, the standard luminance difference, and the standard ratio are predetermined standards, for example, ITU-R Recommendation BT. Reference values indicated in guidelines such as recommended in 1702 can be used.

Then, the flicker video detection device uses the large luminance difference pixel number accumulating means to determine, for each frame, the number of pixels in which the difference in luminance value of the corresponding pixel in the adjacent frame is equal to or greater than the reference luminance difference as the large luminance difference pixel number. Accumulate. If the number of large luminance difference pixels is larger than the number of determination reference pixels, it can be said that the frame has a visually inappropriate luminance change in the actual viewing environment.
Therefore, the flicker video detection apparatus compares the number of large luminance difference pixels and the number of determination reference pixels by an inappropriate frame determination unit, so that the frame generates a visually inappropriate luminance change (inappropriate frame). Frame).
Then, the flicker video detection device determines in advance within a predetermined time the number of frames that have been determined by the improper section detection means to be a frame in which an inappropriate frame determination means causes a visually inappropriate luminance change. By determining whether or not the reference number of times is exceeded, a time interval of a video that may cause a photosensitive seizure is detected. The predetermined time and the standard number of times are predetermined standards, for example, ITU-R recommendation BT. As recommended in 1702, the predetermined time is 1 second, and the reference number is 3 times (6 times as the number of luminance changes).

  The video display device according to claim 2 detects a time interval of a video that may cause a photosensitive seizure from an input video, and the flicker video. In the time interval detected by the detection device, an output control means for controlling the output of the video in the time interval is provided.

In such a configuration, the video display device detects a time interval of a video that may cause a photosensitive seizure by the flicker video detection device.
Then, the video display device controls the output of the frames in the corresponding time interval in the time interval detected by the flicker image detection device by the output control means. For example, the output control means displays the still image of the frame immediately before the time interval or displays a predetermined still image, thereby eliminating the change in luminance.

  Furthermore, the flicker video detection program according to claim 3 is configured such that an inappropriate standard predetermined as a visually inappropriate luminance change, a luminance characteristic of a video display device that is an actual viewing environment, a size of a display area, and a visual field are displayed. Based on the distance, in order to detect a section of the video that may cause a photosensitive seizure from the video displayed on the video display device, the computer is connected to a luminance value specifying means, a judgment reference pixel number calculating means, The luminance difference pixel number accumulating unit and the improper frame determining unit are configured to function.

In such a configuration, the flicker video detection program specifies the luminance value corresponding to the pixel value based on the specific luminance characteristics of the video display device by the luminance value specifying means.
Further, the flicker video detection program uses the determination reference pixel number calculation unit to determine whether the reference is an inappropriate reference, the reference viewing distance, the size of the reference display area, and the luminance between adjacent frames with respect to the size of the reference display area. Based on the reference ratio of the pixels whose difference is greater than or equal to the reference luminance difference, the number of pixels that becomes the reference ratio with respect to the size of the display area of the video display device at the actual viewing distance is calculated as the determination reference pixel number.

Then, the flicker video detection program uses the large luminance difference pixel number accumulating means to determine, as the large luminance difference pixel number, the number of pixels in which the luminance value difference of the corresponding pixel in the adjacent frame is equal to or larger than the reference luminance difference for each frame. Accumulate.
Then, the flicker video detection program compares the number of large luminance difference pixels and the number of determination reference pixels by an improper frame determination unit, so that the frame generates a visually inappropriate luminance change (inappropriate frame). Frame).

  Further, the improper luminance pixel number calculating method according to claim 4 is based on an improper criterion predetermined as a visually improper luminance change and a luminance characteristic of a video display device that is an actual viewing environment. An inappropriate luminance pixel number calculation method for calculating the number of pixels that result in a visually inappropriate luminance difference from a video displayed on the video display device, comprising: a luminance value specifying step; and a large luminance difference pixel number accumulating step. It is characterized by including.

In this procedure, the inappropriate luminance pixel number calculating method specifies the luminance value corresponding to the pixel value based on the luminance characteristic by the luminance value specifying means in the luminance value specifying step. As a result, the pixel value of each pixel in the display area when displaying the video is associated with the actual luminance value.
Then, the inappropriate luminance pixel number calculation method is a large luminance difference pixel number accumulating step, wherein the luminance difference pixel number accumulating means determines that the luminance difference of pixels at the same coordinates between adjacent frames is greater than or equal to the reference luminance difference for each frame. Are accumulated as the number of pixels that result in a visually inappropriate luminance difference.
This accumulated number of pixels is the total number of pixels that cause a visually inappropriate luminance difference in the video display device actually viewed by the viewer.

  Furthermore, the flicker detection method according to claim 5 includes an improper criterion predetermined as a visually improper luminance change, a luminance characteristic of a video display device that is an actual viewing environment, a size of a display area, and a viewing distance. And a flicker detection method for detecting a visually inappropriate luminance change from a video displayed on the video display device, including a determination reference pixel number calculating step and an inappropriate frame determination step. Features.

In such a procedure, the flicker detection method uses a determination reference pixel number calculation unit to calculate, for each frame, a reference viewing distance, a size of the reference display area, and a luminance difference between adjacent frames with respect to the size of the reference display area. Based on the reference ratio of pixels that are equal to or greater than the reference luminance difference, the number of pixels that is the reference ratio with respect to the size of the display area at the viewing distance is calculated as the determination reference pixel number. As a result, these standards are converted into standards corresponding to the actual viewing environment.
In the flicker detection method, the improper frame determination means calculates, for each frame, the number of pixels in which the difference between the luminance values of corresponding pixels in adjacent frames is equal to or greater than the reference luminance difference, and the determination reference pixel number calculating step. It is determined whether or not the frame is a frame that causes a visually inappropriate luminance change by comparing with the determination reference pixel number calculated in (1).

The present invention has the following excellent effects.
According to the invention described in claim 1 or claim 3, in a viewing environment in which the size and viewing distance of the video display device that the viewer actually views are different, the time interval of the video that is likely to cause a photosensitive seizure is determined. Can be detected.

  According to the second aspect of the present invention, in a viewing environment in which the size and viewing distance of the video display device that is actually viewed by the viewer is detected, the time interval of the video that is likely to cause a photosensitive seizure is detected. Since it is possible to stop outputting the frames in the time interval, it is possible to display an image that prevents the occurrence of a photosensitive attack.

  According to the fourth aspect of the present invention, in the video display device that is actually viewed by the viewer, it is possible to calculate the number of pixels that cause a visually inappropriate luminance difference. As a result, even in a video display device different from the standard display, the number of pixels having an appropriately inappropriate luminance difference can be calculated.

  According to the fifth aspect of the present invention, it is possible to detect flicker that is highly likely to cause a light-sensitive seizure in viewing environments in which the size and viewing distance of the video display device actually viewed by the viewer are different.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Outline of video display device]
First, the outline of the video display apparatus according to the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram for explaining an outline of a video display device according to the present invention. The video display device 1 reproduces and displays a video signal while controlling display of a frame in which a visually inappropriate luminance change occurs.
Here, as shown in FIG. 1, the video display device 1 includes a characteristic of luminance inherent to the video display device 1 (maximum luminance value Lmax, gamma value γ), the size of the display region R, and the viewer H. Based on the distance (viewing distance d), a guideline such as an ITC guideline is adapted to an environment where the viewer H is actually viewing the video.
As a result, the video display device 1 can suppress a luminance change that is not visually appropriate according to the viewing environment on the side that actually displays the video, not on the side that produces the video (such as a TV program). Can display images that do not cause light-sensitive seizures.

[Configuration of video display device]
Next, the configuration of the video display device will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the video display apparatus according to the present invention. Here, the video display device 1 includes an A / D conversion means 2, a frame memory 3, a D / A conversion means 4, an output means 5, a flicker video detection device 6, and an output control means 7. Yes.

  The A / D conversion means 2 converts the input video signal, which is an analog signal, into a digital signal and stores it in the frame memory 3 for each frame (frame image) which is a video display unit. The A / D conversion means 2 samples the video signal for each pixel (horizontal x pixel, vertical y pixel) in the display region R, and quantizes the luminance of each pixel to a predetermined level. Here, the level is set to pixel values “0” to “255”.

  The frame memory 3 stores video in units of frames and is a general storage unit such as a video memory. The frame memory 3 functions as a buffer for storing a plurality of frames in order to detect a time interval (inappropriate image interval) of an image that may cause a light-sensitive seizure in the flicker image detection device 6 to be described later. To do.

  The D / A conversion means 4 sequentially reads out the frames stored in the frame memory 3, converts them into analog signals, and outputs them as output signals to the output means 5. Note that, when a plurality of frames are stored in the frame memory 3, the D / A conversion means 4 reads the frames in time series by sequentially changing the reading position.

  The output means 5 is a general display device such as a liquid crystal display, a plasma display, a projector, or a CRT. Here, the output unit 5 is provided in the video display device 1, but the output signal output from the D / A conversion unit 4 is separated from the output signal output from the D / A conversion unit 4. It is good also as outputting to an output means.

The flicker video detection device 6 detects a video segment that may cause a photosensitive seizure from the video. Note that a section of a video that may cause a light-sensitive seizure refers to a video section that occurs at a frequency greater than or equal to the frequency at which a visually inappropriate luminance change occurs. Here, the flicker image detection device 6 sequentially reads out the frames stored in the frame memory 3, and starts and ends the frames that have generated a visually inappropriate luminance change based on the luminance change between the frames. Are output as inappropriate video section information. The inappropriate video section information is information for specifying a start frame and an end frame, and is, for example, a frame number or a frame address stored in the frame memory 3.
Further, the flicker video detection device 6 is an environment in which the viewer H is actually viewing the video, and the inherent luminance characteristics (maximum luminance value Lmax, gamma value γ) of the video display device 1 and the display region R The size and distance from the viewer H (viewing distance d) are used as viewing environment parameters, and based on the viewing environment parameters, a section of the image that may cause a photosensitive seizure is detected. The detailed configuration of the flicker image detection device 6 will be described later.

  The output control means 7 controls the output of the video in the video section that may cause the photosensitive seizure detected by the flicker video detection device 6. Here, the output control means 7 stops the reading from the frame memory 3 when the start of the inappropriate frame is notified as the inappropriate video section information from the flicker video detection device 6, thereby outputting the video. Stop. Thereafter, the output control means 7 starts reading out from the frame memory 3 at the stage when the end of the improper frame is notified from the flicker video detection device 6, thereby restarting video output. As a result, the video output is stopped in the inappropriate video section.

  Further, the output control means 7 fixes the read position from the frame memory 3 when the start of the improper frame is notified as the improper video section information from the flicker video detection device 6, and the end of the improper frame is terminated. The reading position may be changed at the notified stage. As a result, the same frame is output in the inappropriate video section.

(Detailed configuration of flicker video detection device)
Next, the detailed configuration of the flicker image detection apparatus 6 described with reference to FIG. 2 will be described with reference to FIG. 3 (refer to FIGS. 1 and 2 as appropriate). FIG. 3 is a block diagram showing the configuration of the flicker video detection apparatus according to the present invention. The flicker video detection device 6 is, for example, an ITU-R recommendation BT. By adapting 1702 to an environment in which the viewer actually views the video, a video section (time section [inappropriate video section]) that may cause a light-sensitive seizure is obtained.

  Here, the flicker video detection device 6 includes a visual environment parameter setting unit 60, a visual environment parameter storage unit 61, a luminance value specifying unit 62, a luminance value table storage unit 63, a determination reference pixel number calculating unit 64, Judgment reference pixel number storage means 65, large luminance difference pixel number accumulation means 66, improper frame determination means 67, and improper section detection means 68 are provided.

  The visual environment parameter setting means 60 is for setting a parameter (visual environment parameter) for specifying the environment when the viewer H views the video display device 1. For example, the visual environment parameter setting unit 60 stores the visual environment parameter in the visual environment parameter storage unit 61 by inputting the visual environment parameter via an input device such as a remote controller or a keyboard (not shown).

The visual environment parameter storage means 61 stores visual environment parameters, and is a general storage means such as a memory or a hard disk.
In this visual environment parameter storage means 61, as the visual environment parameters, the maximum luminance value Lmax, the gamma value γ, which is a value indicating the luminance characteristic unique to the output means 5, the size (diagonal length) of the display region R, and video display are displayed. The viewing distance d, which is the distance from the device 1 to the viewer H, is stored in advance.

  Since the maximum luminance value Lmax, the gamma value γ, and the size (diagonal length) of the display region R are characteristic values that depend on the output means 5, if the characteristic values are known, the visual environment parameter memory is stored in advance. Store in the means 61. When the output means 5 has a different configuration and its type changes, the viewer H inputs the characteristic value of the output means 5 via the visual environment parameter setting means 60, and the visual environment parameter storage means. 61 is stored.

  The luminance value specifying unit 62 specifies the luminance value corresponding to the pixel value of the frame based on the luminance characteristics of the video display device 1. For example, the luminance value specifying means 62, based on the maximum luminance value Lmax and the gamma value γ stored in the visual environment parameter storage means 61, as shown in the following equation (1), the pixel value p (p = 0) ˜255) to calculate the luminance value L (p).

  Here, the luminance value specifying means 62 calculates the above equation (1) for all the pixel values p in advance and uses the luminance value L (p) for the pixel value p as a luminance value table. I will remember it. The luminance value specifying means 62 may calculate for each frame every time a frame is stored in the frame memory 3.

  The luminance value table storage unit 63 stores a luminance value table in which the pixel value specified by the luminance value specifying unit 62 is associated with the luminance value, and is a general storage unit such as a memory or a hard disk. .

  The determination reference pixel number calculation means 64 serves as a determination reference as to whether or not the frame has caused a visually inappropriate luminance change based on a criterion (unsuitable criterion) predetermined as a visually inappropriate luminance change. The number of pixels (judgment reference pixel number) is calculated. The determination reference pixel number calculated by the determination reference pixel number calculation unit 64 is stored in the determination reference pixel number storage unit 65.

ITU-R recommendation BT. In 1702, when a display device whose display area has a diagonal size of 25 inches is viewed at a viewing distance of 2 m based on a reference that causes an inappropriate luminance change, a luminance difference of blinking between frames is 20 cd / m. It is assumed that the number of blinking is ² or more and the blinking area exceeds 25% of the entire display area and blinks three times or more per second.

Therefore, the determination reference pixel number calculation means 64 is 25 inches (25 × 2.54 cm: size of the reference display area), 2 m (reference viewing distance), 20 cd / m ² (reference luminance difference), 25% (reference ratio). ) And the number of pixels (determination reference pixel number Nmax) of the display area R of the output means 5 corresponding to the reference ratio at the viewing distance d is calculated by the following equation (2). X and y indicate the number of horizontal pixels and the number of vertical pixels of the display area R, respectively, S indicates the diagonal length (cm) of the display area R, and d indicates the viewing distance (cm).

  The determination reference pixel number storage unit 65 stores the determination reference pixel number calculated by the determination reference pixel number calculation unit 64, and is a general storage unit such as a memory or a hard disk.

The large luminance difference pixel number accumulating unit 66 accumulates, as the large luminance difference pixel number, the number of pixels in which the difference between the luminance values of the corresponding pixels in adjacent frames is equal to or greater than the reference luminance difference for each frame. This large luminance difference pixel number is output to the improper frame determination means 67.
Here, the large luminance difference pixel number accumulating unit 66 calculates the difference between the luminance values of the pixels corresponding to the same position in two consecutive frames stored in the frame memory 3 as the reference luminance difference (here, By accumulating pixels that are ²⁰ cd / m ² ) or more, the number of large luminance difference pixels is obtained. Further, the large luminance difference pixel number accumulating unit 66 refers to the luminance value table stored in the luminance value table storage unit 63 based on the pixel value of the pixel of the frame, so that the luminance value corresponding to the pixel value is obtained. And the difference in the luminance value of the pixel between frames is obtained.

The improper frame determination unit 67 compares the determination reference pixel number stored in the determination reference pixel number storage unit 65 with the large luminance difference pixel number accumulated by the large luminance difference pixel number accumulation unit 66. This is to detect a frame in which a visually inappropriate luminance change exists.
That is, the improper frame determination unit 67 determines that the frame is an improper frame when the number of large luminance difference pixels is larger than the determination reference pixel number. Information indicating whether or not the frame is an improper frame is output to the improper section detecting means 68.

  The improper section detecting unit 68 determines whether or not the number of frames determined as the improper frame by the improper frame determining unit 67 exceeds a reference number that is a predetermined reference value within a predetermined time. Thus, a time interval (inappropriate image interval) of a video that may cause a photosensitive seizure is detected.

Here, the improper section detecting means 68 is the ITU-R recommendation BT. An inappropriate video section is detected based on whether or not blinking, which is a reference in 1702, occurs at least three times per second (six times of luminance change).
In other words, the improper section detection unit 68 sets a section in which the improper frame determination unit 67 is notified of the occurrence of an improper frame six times or more per second as the improper video section. For example, when the video signal is an NTSC signal, since the frame frequency is 30 Hz, a section notified more than six times in 30 frames is set as an inappropriate video section.

The improper section detecting means 68 stores the number of occurrences of improper frames in a memory (not shown) and sets the start frame and end frame of the improper video section. The setting operation of the inappropriate video section will be described in detail in the operation of the flicker video detection device 6 described later.
Then, the inappropriate section detection unit 68 outputs information indicating the start frame and the end frame of the inappropriate video section to the output control unit 7 as inappropriate video section information.

By configuring the flicker video detection device 6 in this way, a fixed determination criterion that is predetermined as a visually inappropriate luminance change can be made to correspond to the actual viewing environment of the viewer H. Thereby, it is possible to detect a video (or its section) that may cause a photosensitive seizure in an actual viewing environment.
It should be noted that here, the determination of a visually inappropriate luminance change is performed according to ITU-R Recommendation BT. Although it was performed in conformity with 1702, the numerical values (the size of the reference display area, the reference viewing distance, the reference luminance difference, and the reference ratio) used for these determinations may be based on other guidelines or the like. .

Further, the flicker video detection apparatus 6 can be operated by a flicker video detection program that causes a general computer to function as each of the means described above.
Thus, the flicker video detection program can detect a video (or its section) that may cause a light-sensitive seizure from video stored in a general video buffer such as a personal computer.

The configuration of the video display device 1 including the flicker video detection device 6 has been described above, but the present invention is not limited to this configuration.
For example, as illustrated in FIG. 4, the video display device 1 </ b> B may include a distance measuring unit 8 in the video display device 1.
The video display device 1B shown in FIG. 4 measures the distance to the viewer by the distance measuring unit 8, and uses the distance as the viewing distance in the visual environment parameter storage unit 61 via the visual environment parameter setting unit 60. Remember. This distance measuring means 8 can be constituted by a general distance sensor.
Thereby, when setting the viewing environment parameter, the operation of the viewer can be reduced, and even if the viewing distance changes during viewing, detection based on the accurate viewing distance can be performed.

Moreover, as shown in FIG. 5, it is good also as a structure of the video display apparatus 1C provided with the brightness | luminance measurement means 9 in the video display apparatus 1. FIG.
In the video display device 1 </ b> C shown in FIG. 5, the luminance measurement unit 9 measures the luminance value of the pixel actually output from the output unit 5. Then, the luminance value specifying unit 62 stores the luminance value for the pixel value in the luminance value table storage unit 63 as a luminance value table. This luminance measuring means 9 can be constituted by a general luminance sensor.

Note that the luminance measuring unit 9 does not need to measure the luminance values for all pixel values. For example, the luminance value specifying unit 62 generates a luminance value table by performing an interpolation operation on the luminance values that have not been measured from the luminance values that have been measured.
Thereby, the luminance value specifying means 62 can obtain the luminance value corresponding to the pixel value even when the maximum luminance value Lmax and the gamma value γ are unknown among the visual environment parameters.

[Operation of video display device (flicker video detection device)]
Next, the operation of the video display apparatus 1 will be described with reference to FIGS. 6 and 7 (refer to FIGS. 2 and 3 for the configuration). Here, the operation of the flicker video detection device 6 which is a characteristic part of the present invention in the video display device 1 will be described. FIG. 6 is a flowchart showing an operation of detecting an improper frame in the flicker video detection apparatus according to the present invention. FIG. 7 is a flowchart showing an operation of detecting an inappropriate video section in the flicker video detection apparatus according to the present invention.

(Luminance value identification step)
First, the flicker video detection device 6 sets a parameter (visual environment parameter) for specifying an environment when the viewer H views the video display device 1 by the visual environment parameter setting means 60, and stores the visual environment parameter storage. It memorize | stores in the means 61 (step S1). Here, the viewing environment parameters are the maximum luminance value Lmax, the gamma value γ, the size of the display region R, and the viewing distance d.
Then, the flicker image detection device 6 calculates the luminance value for the pixel value based on the maximum luminance value and the gamma value stored in the visual environment parameter storage unit 61 by the luminance value specifying unit 62 ((( 1), a brightness value table is generated and stored in the brightness value table storage means 63 (step S2).

  Steps S1 and S2 are preparation stages until the viewer H views the video, and when the viewer actually views the video, the following operations after step S3 are being performed. It is done sequentially. In the following operation, the description will be made assuming that the frame frequency of the video is N (Hz).

(Judgment reference pixel count calculation step)
Further, the flicker image detection device 6 uses the determination reference pixel number calculation means 64 to determine whether the frame is visually inappropriate from the size of the display area and the viewing distance based on a predetermined criterion as a visually inappropriate luminance change. The number of pixels (determination reference pixel number) serving as a criterion for determining whether or not a significant luminance change has occurred is calculated (step S3). That is, the flicker video detection device 6 is an ITU-R recommendation BT. The number of pixels corresponding to 25% of the entire display area in a display device having a display area size of 25 inches at a viewing distance of 2 m, which is the reference indicated by 1702, is as follows. The number of pixels corresponding to the display area R of the video display device 1 is calculated (see the above equation (2)). Accordingly, the determination reference pixel number becomes a determination reference in the actual viewing environment.

(Total luminance difference pixel count cumulative step)
Then, the flicker video detection device 6 is configured such that, at the stage where the video signal is reproduced in the frame memory 3, the difference in luminance value of the corresponding pixel in the adjacent frame is determined for each frame by the large luminance difference pixel number accumulating unit 66. The number of pixels having a luminance difference (20 cd / m ² ) or more is accumulated as the number of large luminance difference pixels (step S4).

(Inappropriate frame determination step)
Then, the flicker image detection device 6 compares the determination reference pixel number calculated in step S3 with the large luminance difference pixel number in the frame accumulated in step S4 by the improper frame determination unit 67. It is determined whether or not the current frame is an inappropriate frame (step S5). That is, the improper frame determination unit 67 determines that the current frame is an improper frame in which an inappropriate luminance change has occurred between adjacent frames when the number of large luminance difference pixels is larger than the determination reference pixel number. If the large luminance difference pixel number is equal to or smaller than the determination reference pixel number, it is determined that the current frame is not an inappropriate frame.

Hereinafter, with reference to FIG. 7, an operation for detecting an inappropriate video section based on the detection result of the inappropriate frame will be described.
When the flicker video detection device 6 determines that the current frame is an inappropriate frame (Yes in step S5 in FIG. 6), the inappropriate section detection unit 68 has generated an inappropriate frame seven times within N frames. (Step 6).

Here, when an improper frame has occurred seven times (Yes in step S6), the improper section detection means 68 determines whether or not the start frame of the improper video section has been set (step S7), and is set. If not (No in step S7), the first inappropriate frame within N frames is set as the start frame of the inappropriate video section in the memory not shown (step S8). Then, it returns to step S3 of FIG. 6 and continues operation | movement.
Note that if an inappropriate frame has not occurred seven times in the determination in step S6 (No in step S6), or if a start frame has already been set in step S7 (Yes in step S7), flicker video detection is performed. The apparatus 6 returns to step S3 in FIG. 6 and continues to operate.
By the operations from step S6 to step S8, the start frame of the inappropriate video section is set in the continuous frames.

On the other hand, if the flicker video detection device 6 determines that the current frame is not an improper frame (No in step S5 in FIG. 6), the improper section detection unit 68 improperly adds to the memory that is not illustrated. It is determined whether the start frame and the end frame of the video section are set and the end frame is not within N frames (step S9).
The reason why it is determined whether or not the end frame is within N frames is that if the end frame is within N frames, the end frame may be further shifted backward.

  Here, when the start frame and the end frame of the inappropriate video section are not set, or when the end frame is within N frames (No in step S9), the inappropriate section detection means 68 detects the inappropriate frame within N frames. It is determined whether or not a proper frame has occurred six times (step S10).

  Here, if an improper frame has occurred six times within N frames (Yes in step S10), the improper section detecting means 68 further determines whether or not the start frame of the improper video section is set. If it is determined (step S11) and is set (Yes in step S11), the current frame is set as the end frame of the inappropriate video section in the memory (not shown) (step S12). Then, it returns to step S3 of FIG. 6 and continues operation | movement.

It should be noted that if an inappropriate frame has not occurred six times within N frames in step S10 (No in step S10), or if an inappropriate video section start frame is not set in step S11 (No in step S11). ), The flicker video detection device 6 returns to step S3 in FIG. 6 and continues its operation.
By the operations from step S9 to step S12, the end frame of the inappropriate video section is set in the continuous frames.

On the other hand, when the start frame and the end frame of the inappropriate video section are set and the end frame is not within N frames (Yes in step S9), the flicker video detection device 6 uses the inappropriate section detection unit 68 to detect the inappropriate video section. Information (for example, a frame number) indicating the start frame and the end frame of the proper video section is output as inappropriate video section information (step S13). Then, the flicker video detecting device 6 cancels the setting of the start frame and the end frame set as the inappropriate video section by the inappropriate section detecting means 68 (step S14).
Thereafter, the flicker video detection device 6 returns to step S3 in FIG. 6 and continues the operation while the video signal is reproduced in the frame memory 3.

  With the above operation, the flicker video detection device 6 makes a fixed determination criterion predetermined as a visually inappropriate luminance change corresponding to the actual viewing environment of the viewer H, and is actually for the viewer H. In addition, it is possible to detect a frame section that causes a visually inappropriate luminance change.

  Thereafter, output of the inappropriate video section is stopped by the output control means 7 of the video display device 1. As a result, the video displayed by the video display device 1 can prevent the occurrence of light-sensitive seizures.

It is explanatory drawing for demonstrating the outline | summary of the video display apparatus concerning this invention. It is a block diagram which shows the structure of the video display apparatus which concerns on this invention. It is a block diagram which shows the structure of the flicker image | video detection apparatus which concerns on this invention. It is a block diagram which shows the other structure of the flicker image | video detection apparatus which concerns on this invention. It is a block diagram which shows the other structure of the flicker image | video detection apparatus which concerns on this invention. It is a flowchart which shows the operation | movement which detects the improper flame | frame in the flicker video detection apparatus based on this invention. 5 is a flowchart illustrating an operation of detecting an inappropriate video section in the flicker video detection device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video display apparatus 2 A / D conversion means 3 Frame memory 4 D / A conversion means 5 Output means 6 Flicker video detection apparatus 60 Visual environment parameter setting means 61 Visual environment parameter storage means 62 Luminance value specification means 63 Luminance value table storage means 64 Judgment reference pixel number calculation means 65 Judgment reference pixel number storage means 66 Large brightness difference pixel number accumulation means 67 Improper frame determination means 68 Improper section detection means 7 Output control means 8 Distance measurement means 9 Luminance measurement means

Claims (5)

Video to be displayed on the video display device based on an inappropriate standard predetermined as a visually inappropriate luminance change and the luminance characteristics, display area size and viewing distance of the video display device which is the actual viewing environment A flicker image detection device for detecting a section of an image that may cause a photosensitive seizure,
A luminance value specifying means for specifying a luminance value corresponding to a pixel value based on the luminance characteristics;
The improper reference, based on a reference viewing distance, a size of a reference display area, and a reference ratio of pixels in which a luminance difference between adjacent frames is equal to or larger than a reference luminance difference with respect to the size of the reference display area Determination reference pixel number calculating means for calculating, as the determination reference pixel number, the number of pixels that becomes the reference ratio with respect to the size of the display area at the viewing distance;
A large luminance difference pixel number accumulating means for accumulating, as a large luminance difference pixel number, the number of pixels in which the difference in luminance value of corresponding pixels in adjacent frames is equal to or greater than the reference luminance difference for each frame;
By comparing the large luminance difference pixel number accumulated by the large luminance difference pixel number accumulation unit with the determination reference pixel number calculated by the determination reference pixel number calculation unit, the frame is visually inappropriate. An improper frame determination means for determining whether or not the frame generates a significant luminance change;
Determining whether or not the number of frames determined by the improper frame determination means to be a frame in which a visually inappropriate luminance change occurs exceeds a predetermined reference number within a predetermined time; Inappropriate section detecting means for detecting a time section of the video that may cause the photosensitive seizure,
A flicker image detection apparatus comprising: In a video display device that displays video,
The flicker video detection device according to claim 1, wherein a time interval of a video that may cause a photosensitive seizure is detected from an input video;
Output control means for controlling the output of the video in the time interval in the time interval detected by the flicker video detection device;
A video display device comprising: Video to be displayed on the video display device based on an inappropriate standard predetermined as a visually inappropriate luminance change and the luminance characteristics, display area size and viewing distance of the video display device which is the actual viewing environment To detect a segment of the video that can cause a light-sensitive seizure,
A luminance value specifying means for specifying a luminance value corresponding to a pixel value based on the luminance characteristics;
The improper reference, based on a reference viewing distance, a size of a reference display area, and a reference ratio of pixels in which a luminance difference between adjacent frames is equal to or larger than a reference luminance difference with respect to the size of the reference display area Determination reference pixel number calculating means for calculating, as the determination reference pixel number, the number of pixels that is the reference ratio with respect to the size of the display area at the viewing distance;
A large luminance difference pixel number accumulating means for accumulating, as the large luminance difference pixel number, the number of pixels in which the difference in luminance value of corresponding pixels in adjacent frames is equal to or greater than the reference luminance difference for each frame;
By comparing the large luminance difference pixel number accumulated by the large luminance difference pixel number accumulation unit with the determination reference pixel number calculated by the determination reference pixel number calculation unit, the frame is visually inappropriate. Improper frame determination means for determining whether or not the frame generates a significant luminance change;
Determining whether or not the number of frames determined by the improper frame determination means to be a frame in which a visually inappropriate luminance change occurs exceeds a predetermined reference number within a predetermined time; Inappropriate section detecting means for detecting a time section of a video in which the visually inappropriate luminance change occurs,
Flicker video detection program characterized by functioning as From a video displayed on the video display device based on an inappropriate standard predetermined as a visually inappropriate luminance change and a luminance characteristic of the video display device that is an actual viewing environment, a visually inappropriate luminance difference An inappropriate luminance pixel number calculation method for calculating the number of pixels to be,
A luminance value specifying step for specifying a luminance value corresponding to the pixel value based on the luminance characteristic by the luminance value specifying means;
Accumulate the number of pixels for which the luminance difference between adjacent frames in the same coordinate between adjacent frames is greater than or equal to the reference luminance difference as the number of pixels that result in an inappropriate luminance difference for each frame. A large luminance difference pixel count cumulative step,
A method for calculating an inappropriate luminance pixel number, comprising: Video to be displayed on the video display device based on an inappropriate standard predetermined as a visually inappropriate luminance change and the luminance characteristics, display area size and viewing distance of the video display device which is the actual viewing environment From the above, a flicker detection method for detecting a visually inappropriate luminance change,
For each frame, the reference reference distance, the size of the reference display area, and the pixel reference for which the luminance difference between adjacent frames is greater than or equal to the reference luminance difference with respect to the size of the reference display area by the determination reference pixel number calculation means A determination reference pixel number calculating step of calculating, as the determination reference pixel number, the number of pixels that becomes the reference ratio with respect to the size of the display area at the viewing distance based on the ratio;
The number of pixels in which the difference in the luminance value of the corresponding pixel in the adjacent frame is equal to or larger than the reference luminance difference and the determination reference pixel calculated in the determination reference pixel number calculating step for each frame by the improper frame determination unit An improper frame determination step of determining whether the frame is a frame that generates the visually inappropriate luminance change by comparing with a number;
The flicker detection method characterized by including.

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