JP2007212664A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which displays video by image quality meeting the position of an audience. <P>SOLUTION: The processing implemented by a CPU equipped in a television which is one embodiment of the liquid crystal display device includes a step (S810) of detecting that the image signal outputted from a camera is written into a memory, a step (S820) of implementing the image processing preset for the data stored into the memory and extracting a face region, a step (S830) of computing the position information of the face region, a step (S840) of computing the visual line angle of the audience with the television, a step (S850) of reading the control data for the purpose of the image quality adjustment from the memory according to the visual line angle, and a step (S860) of outputting the instruction signal of the image quality adjustment based on the read control data to an image quality adjustment circuit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that can control display of an image in accordance with the position of a viewer.

  Regarding information processing devices such as television receivers and PCs (Personal Computers) and other display devices, devices that use an LCD panel (Liquid Crystal Display) to display images or images have become widespread. In a display device using an LCD panel, when the viewing angle with respect to the display surface of the LCD panel is different, there is a problem in that contrast, color tone, and other image characteristics change. Various improvements have been made to LCD panels having such properties. As a result, in a general use environment, a considerably wider viewing angle has been secured compared to the conventional viewing angle.

  For example, in Japanese Patent Laid-Open No. 11-95738 (Patent Document 1), when the user changes the attitude of viewing the display screen, or when the user viewing the display screen changes, the user changes the display screen. Disclosed is an automatic display adjustment device for a display device that can always maintain an optimal display state without limiting users by enabling automatic adjustment to an optimal display state according to a difference in viewing angle. is doing.

  Japanese Patent Laid-Open No. 8-68276 (Patent Document 2) discloses an LCD screen adjustment device that can view a liquid crystal screen in the best state regardless of the height of the viewer.

  Japanese Patent Laying-Open No. 2003-186462 (Patent Document 3) discloses an image display device that can always display an image with good visibility according to the posture and position of a user.

  Japanese Patent Laid-Open No. 2000-132152 (Patent Document 4) expands the display range, obtains a display quality and viewing angle appropriate for the observer, prevents unnecessary power consumption and component deterioration, and displays a moving image even with low processing capability. Is disclosed.

Japanese Translation of PCT International Publication No. 2002-534209 (Patent Document 5) discloses a video conference system that can automatically determine presets of appropriate camera parameters in response to participants attending a video conference.
JP-A-11-95738 JP-A-8-68276 JP 2003-186462 A JP 2000-132152 A Special Table 2002-53409

  However, even in an LCD panel in which a wider viewing angle is ensured than before, there is no change in gamma characteristics, color inversion and other image display characteristics. For this reason, depending on the position of the viewer of the television, the displayed video may not be displayed in a manner that is satisfactory to the viewer.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a liquid crystal display device in which a change in display characteristics based on the position of a viewer is suppressed.

  In order to solve the above problems, a liquid crystal display device according to an aspect of the present invention includes a display that displays an image in a liquid crystal display area, a camera that is attached to the display and that captures a subject and outputs an image signal, and an image signal Extracting means for extracting the face area of the viewer based on the video, and a first feature value storing the first feature amount representing the face area of the viewer previously acquired based on the first image signal from the camera. Storage means. The first feature amount is acquired by photographing of the viewer at a predetermined position on the optical axis center of the camera. The liquid crystal display device responds to display of the video on the display, shooting control means for outputting an instruction to shoot a viewer of the video, a first feature amount, and a second image acquired in response to the instruction Authentication means for confirming whether or not the viewer is registered in the liquid crystal display device based on the second feature amount calculated using the signal, and when the viewer is registered in the liquid crystal display device , A means for extracting a feature point of the viewer based on the second image signal, a means for calculating a feature amount of the viewer based on the feature point, and a face area of the viewer based on the feature amount. The direction from the optical axis center of the camera to the viewer and the normal line of the liquid crystal display area based on the means for calculating the position information for specifying the position, the first feature value, the second feature value, and the position information The angle formed with the direction is calculated as the gaze angle Calculated by a degree calculation means, a second storage means for storing control data defined in advance according to each of a plurality of line-of-sight angles in order to adjust the image quality of the video displayed on the display, and the angle calculation means Control means for adjusting the image quality of the video displayed on the display based on the control data corresponding to the viewing angle.

  A liquid crystal display device according to another aspect of the present invention includes a display unit that displays a video in a liquid crystal display region, an acquisition unit that acquires an image signal generated based on photographing of a subject, and a video viewing based on the image signal. In the liquid crystal display device based on the position information, the extracting means for extracting the person's face area, the position information calculating means for calculating the position information for specifying the position of the viewer's face area in the image based on the image signal, Angle calculation means for calculating a line-of-sight angle formed between a normal direction of the liquid crystal display area from a predetermined reference position and a direction from the reference position to the viewer, and image quality adjustment of the video displayed on the display means In order to define the image data, a storage unit that stores control data defined in advance according to each of a plurality of line-of-sight angles, and a control data corresponding to the line-of-sight angle calculated by the angle calculation unit. There are, and a control means for adjusting the image quality of an image displayed on the display means.

Preferably, the acquisition unit includes an imaging unit that images a subject and outputs an image signal.
Preferably, the imaging means is attached to the display means. The angle calculation means calculates an angle formed between the direction to the viewer and the normal direction from the optical axis center of the imaging means as the viewing angle.

  Preferably, the angle calculation means calculates a vertical component and a horizontal component of the line-of-sight angle.

  Preferably, the liquid crystal display device calculates the feature amount of the face area extracted by the image capturing control unit that outputs an instruction to image the viewer of the image in response to the display of the image by the display unit. Using the amount calculation means, the first feature amount representing the face area of the viewer acquired in advance based on the first image signal from the imaging means, and the second image signal acquired in response to the instruction Authentication means for confirming whether or not the viewer is registered in the liquid crystal display device on the basis of the second feature amount calculated in this way. The position information calculation means calculates position information in the image based on the second image signal when the viewer is registered in the liquid crystal display device.

  Preferably, the acquisition unit includes a first imaging unit that captures a subject and outputs a first image signal, and a second imaging unit that captures the subject and outputs a second image signal. The positional relationship between the first imaging unit and the second imaging unit with respect to the display unit is defined in advance. The extraction means extracts the viewer's first face area based on the first image signal and the viewer's second face area based on the second image signal. The position information calculation means calculates first position information for specifying the center of the first face area and second position information for specifying the center of the second face area. The liquid crystal display device performs a stereo measurement process based on the predefined positional relationship, the first position information, and the second position information, thereby providing a first image from the first imaging means to the viewer. And a distance calculating means for calculating a second distance from the second imaging means to the viewer. The angle calculation means calculates the line-of-sight angle based on the first distance and the second distance.

  Preferably, the liquid crystal display device further includes calculation means for calculating the number of face regions extracted by the extraction means. The control means prohibits image quality adjustment when the number of face regions is plural.

  Preferably, the liquid crystal display device further includes a calculation unit that calculates the number of face regions extracted by the extraction unit, and an area calculation unit that calculates the area of the face region. The control means specifies the face area having the maximum area calculated by the area calculation means when the number of face areas is plural, and the viewer corresponding to the face area having the maximum area from the reference position The image quality is adjusted using the angle formed between the direction with respect to and the normal direction as the viewing angle.

  Preferably, the extraction means includes a plurality of elements for storing data corresponding to the face area. The area calculating means calculates the area of the face area by calculating the number of elements in which data corresponding to the face area is stored.

  Preferably, the position information calculation means is a means for extracting a feature point of the viewer based on the image signal, a means for calculating the feature amount of the viewer based on the feature point, and a position based on the feature amount. Means for calculating information.

  Preferably, the liquid crystal display device uses the first feature amount corresponding to the size of the viewer's face at the position, which is acquired in advance by photographing the viewer at the position defined in advance with respect to the liquid crystal display device. When the feature value storage means for storing and the display means are displaying the video, a second feature value corresponding to the size of the face of the viewer of the video is calculated based on the face area extracted by the extraction means. And a distance calculation means for calculating the distance between the viewer and the liquid crystal display device by comparing the first feature quantity and the second feature quantity. The angle calculation means calculates the line-of-sight angle based on the distance calculated by the distance calculation means.

  Preferably, the display means includes a plurality of display elements. The control means adjusts the image quality by controlling the driving of each display element based on the distance calculated by the distance calculation means and the line-of-sight angle calculated by the angle calculation means.

  Preferably, the acquisition unit includes a signal input unit that receives an input of an image signal.

  According to the liquid crystal display device of the present invention, the image quality of the displayed video is appropriately corrected according to the position of the viewer, so that the viewer can appreciate a clear video.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
FIG. 1 is a front view of a television 100 according to the first embodiment of the present invention. The television 100 includes a liquid crystal display 130, a camera 150, and speakers 140a and 140b. The speakers 140a and 140b are speakers that can output stereo sound, for example.

  FIG. 2 is a block diagram illustrating a hardware configuration of television 100. The television 100 includes an antenna 102 that receives a video / audio signal, a tuner 114 that is connected to the antenna 102 and acquires a video / audio signal of a channel instructed to select a channel, and an external device that receives an input of the video / audio signal from the outside. An input unit 104, a light receiving unit 106 that receives a signal transmitted from a remote control terminal (to be described later), an operation unit 108 that receives an instruction input from the viewer to the television 100, and a CPU (Central Processing Unit) that controls the operation of the television 100 ) 110 and a memory 112. The memory 112 is, for example, a volatile memory, but may be a nonvolatile memory.

  The television 100 is further connected to the external input unit 104 and the tuner 114, and switches from the switching circuit 116 that switches the output destination of the video / audio signal based on the signal from the CPU 110, and outputs from the switching circuit 116 based on the signal from the CPU 110. A signal processing circuit 120 that outputs a signal to be separated into a video signal and an audio signal, a driver 128 that amplifies and outputs the video signal output from the signal processing circuit 120, and a video signal output from the driver 128 And a liquid crystal display 130 for displaying an image based on the above.

  The signal processing circuit 120 separates the signal from the switching circuit 116 into a video signal and an audio signal, and image quality adjustment of the video signal output by the separation circuit 122 based on an image adjustment instruction output from the CPU 110. And an OSD circuit 126 that generates a video signal to be displayed on the liquid crystal display 130 based on the signal from the CPU 110 and the video signal output from the image quality adjustment circuit 124.

  The television 100 further receives an audio signal output from the separation circuit 122, and amplifies the audio signal based on an instruction from the CPU 110 and outputs the audio signal from amplifiers 136a and 136b and amplifiers 136a and 136b, respectively. Speakers 140a and 140b that output sound based on the sound signal are provided. Further, a memory 152 for storing an image signal output from the camera 150 is disposed between the camera 150 and the CPU 110. The CPU 110 executes image processing to be described later based on data stored in the memory 152. The memories 112 and 152 are nonvolatile memories. The memories 112 and 152 may be realized as the same memory. In this case, the data area secured in the memory 112 and the data area secured in the memory 152 are each secured in the same memory.

  A usage mode of the television 100 will be described with reference to FIG. FIG. 3 is a diagram illustrating a state where the television 100 is installed in the room 10. In the room 10, a TV 100 and a chair 11 are arranged. A viewer 12 sits on the chair 11. The viewer 12 has a remote control terminal 300.

  Here, the terms used to identify the positional relationship between the television 100 and the viewer in this embodiment are defined. First, a horizontal line 320 that passes through the center of the television 100 is defined as a line that passes through a position that is a predetermined distance 340 away from the top of the television 100, for example. The distance 340 corresponds to, for example, the distance between a line passing through the central axis of the liquid crystal display 130 and the upper part of the casing of the television 100.

  Next, the viewing angle 310 in the vertical direction is defined as an angle between the horizontal line 320 and the viewing line 330 that connects the television 100 and the viewer 12 and passes through the central axis of the liquid crystal display 130. In this case, the position of the viewer 12 is defined as a characteristic part of the viewer 12 analyzed based on the image data acquired by the camera 150 (for example, the center of the viewer's eyes). Further, as will be described later, when the television 100 has a registration function for each viewer, a position that is a predetermined distance from the television 100 as a reference position for acquiring data for registering the viewer. The chair 11 is installed, and the viewer registration process is executed by photographing the viewer in the chair 11 installed in such a place.

  With reference to FIG. 4, the positional relationship between the television 100 and the viewer will be further described. FIG. 4 shows the room 10 from above. The viewer 12 is present at a position away from the television 100 by a predetermined distance 440. The viewer 12 is located on the center line 420 of the liquid crystal display 130. Here, the distance 440 is defined as a distance from a line 410 passing through the front surface of the housing of the television 100, for example.

  Next, a case where the position where the viewer 12 sits is changed will be described. For example, the television 100 may be viewed at a position indicated as the viewer 405. In this case, the distance between the television 100 and the viewer 405 is a distance 440, which is the same as the distance for the viewer 12. However, a line 450 connecting the television 100 and the viewer 405 is different from a line connecting the viewer 12 and the television 100 (center line 420). That is, when a line 450 connecting the television 100 and the viewer 405 is defined, a vertical viewing angle 452 is formed between the line 450 and the center line 420.

  Further, when the viewer changes the position and views the television 100 as the viewer 404, for example, a line connecting the television 100 and the viewer 404 (that is, a line of sight) is represented as a line 460. In this case, the horizontal line-of-sight angle 462 formed between the line 460 and the center line 420 is larger than the above-described horizontal line-of-sight angle 452.

  Further, viewer recognition by the television 100 will be described. When the viewer is watching the television 100 at the position indicated as the viewer 12, the camera 150 acquires an image of a dotted line 430 at a position away from the television 100 by a distance 440. Here, if the distance 440 is predetermined for the television 100, the television 100 can recognize the face of the viewer 12 based on the value of the distance 440 and the image data acquired by photographing with the camera 150. If this state is stored in the television 100 as authentication data, for example, the same viewer 12 existing on the center line 420 can be recognized in the same manner using this data as a reference.

  For example, when the viewer is the viewer 402 on the dotted line 431, the face of the viewer 402 is recognized by using a similarity relationship based on the ratio between the distance 441 between the dotted line 410 and the dotted line 431 and the distance 440. be able to. In this case, the face of the viewer 402 photographed by the camera 150 is displayed larger than the image of the face of the viewer 12 in accordance with the distance ratio.

  On the other hand, when the same viewer is viewing the television 100 as the viewer 403 from a distance from the reference position, the television 100 has a ratio of the distance 442 between the dotted lines 410 and 432 to the distance 440. Based on this, the face image of the viewer 403 can be recognized. In this case, the face image photographed by the camera 150 is displayed in a small size according to the ratio of the distances. Therefore, by adding the above-described ratio to the face image of the viewer 12, the same viewer can be displayed. Can be recognized.

  In this way, the viewer's recognition and viewing position (distance from the television 100 to the viewer) existing on the center line 420 can be specified. In the above description, the case where the position of the camera 150 exists in the center of the television 100 and the distance 440 between the television 100 and the viewer 12 at the standard position is known has been described.

  On the other hand, for example, when the camera 150 is not installed at the center of the television 100, the line passing through the optical axis of the camera 150 is used as the center line in that case, instead of the center line 420. The distance between the television 100 and the viewer can be identified in the same manner.

  Next, a case where the viewer is watching television 100 as viewer 404, for example, will be described. The image of the viewer 404 and the image of the viewer 402 captured by the camera 150 are specified in a state in which the center of each image is shifted by an amount corresponding to the distance 470. Here, when the positional relationship between the viewer 402 and the viewer 12 and the distance 440 defined in advance between the viewer 12 and the television 100 are taken into account, the deviation of the central axis corresponding to the distance 420 is caused by the television 100. It can be recognized as a center shift on the image data. As will be described later, the CPU 110 of the television 100 can calculate a horizontal line-of-sight angle 462 by performing arithmetic processing based on a known surveying method using the deviation of the central axis. The viewing angle 452 in the horizontal direction when the viewer is watching the television 100 as the viewer 405 is similarly calculated.

  Referring to FIG. 5, CPU 110 that realizes television 100 according to the present embodiment will be described. FIG. 5 is a block diagram showing a configuration of functions realized by CPU 110. The CPU 110 includes a face area extraction unit 502, a feature amount calculation unit 504, an area number calculation unit 506, an area calculation unit 508, an imaging control unit 510, an authentication unit 512, a position information calculation unit 514, and a distance calculation. A unit 516, an angle calculation unit 518, and an image quality control unit 520. Each function is realized as cooperation between hardware and software by the CPU 110 executing a program that realizes the function. Alternatively, instead of the program, it can be realized as a hardware configuration by combining circuit elements for realizing each process.

  The face area extraction unit 502 extracts the face area of the viewer of the television 100 based on the image signal output from the camera 150. In another aspect, when television 100 has a plurality of cameras, face area extraction unit 502 includes a first face area of the viewer based on a first image signal output from the first camera, and a second The second face area of the viewer based on the second image signal output from the camera is extracted. Preferably, the face area extraction unit 502 stores data corresponding to the face area corresponding to each of the display elements constituting the liquid crystal display 130.

  The feature amount calculation unit 504 calculates the feature amount of the face area extracted by the face area extraction unit 502. The calculated feature amount includes, for example, an interval between eyes of the viewer's face, an interval between eyes and mouth, or a ratio of these intervals. Specifically, the feature amount calculation unit 504 extracts feature points from the image signal, specifies a viewer's face image based on each feature point, and further specifies each part of the face. The feature amount calculation unit 504 calculates each feature amount described above based on information specifying each part. Here, the information for specifying each part is, for example, position data in an area allocated to the memory for image processing.

  The area number calculation unit 506 calculates the number of face areas extracted by the face area extraction unit 502. For example, when one viewer is watching the television 100, the number-of-regions calculation unit 506 calculates the number of face regions “1”. This calculation is performed based on the number of feature amounts calculated by the feature amount calculation unit 504, for example. For example, when a plurality of feature amounts defining the interval between eyes are calculated, the region number calculation unit 506 determines that there are regions as many as the number of feature amounts, and outputs the number as the number of regions.

  The area calculation unit 508 calculates the area of the face region based on the face region data extracted by the face region extraction unit 502. Here, the area of the face region is expressed as the number of image sensors used to recognize the viewer of the television 100, for example. Specifically, the area calculation unit 508 calculates the area of the face region by calculating the number of elements in which data corresponding to the face region is stored.

  Shooting control unit 510 outputs to camera 150 an instruction to shoot the viewer of television 100 in response to the display of video on liquid crystal display 130. Further, the shooting control unit 510 outputs a shooting instruction of the viewer of the television 100 to the camera 150 based on the shooting command received by the light receiving unit 106 or the shooting command input via the operation unit 108.

  Preferably, the feature amount calculation unit 504 uses the face region extraction unit 502 to extract a feature amount corresponding to the size of the viewer's face of the displayed image when the liquid crystal display 130 displays the image. It calculates based on the done face area.

  The authentication unit 512 receives the first feature amount representing the acquired face area of the viewer expressed based on the first image signal from the camera 150 and the second image signal acquired based on the instruction from the CPU 110. It is confirmed whether or not the viewer is a viewer registered in advance in the television 100 by comparing the second feature amount calculated by using the second feature amount. Here, the first feature amount is stored in the memory 112, for example.

  The position information calculation unit 514 calculates data representing the center of the viewer's face area in the image based on the image signal output from the camera 150. This data is acquired, for example, as coordinate information in a memory area reserved for image processing. As data representing the center of the face area, for example, the coordinate value of the midpoint of the line connecting the viewer's eyes, the midpoint of the line connecting the head and chin of the face area, and the like can be used.

  Preferably, the position information calculation unit 514 calculates data representing the center of the viewer's face area in the image based on the second image signal when the viewer is registered in advance in the television 100.

  In another aspect, when television 100 is configured to include the first camera and the second camera, position information calculation unit 514 is based on the first image signal output from the first camera. First and second specifying the center of each area of the viewer's first face area and the viewer's second face area based on the second image signal output from the second camera Each position data is calculated.

  The distance calculation unit 516 executes a process according to a known surveying method based on the calculated position data, and thereby the distance from the first camera to the viewer and the distance from the second camera to the viewer. And calculate. Specifically, the positional relationship between each camera and the television, that is, the distance from the center of the television to the center of each camera is known. When the optical axis of the camera is parallel to the central axis of the television 100, the center deviation corresponding to the distance is calculated according to the image data obtained by shooting.

  If the viewer is far away from the reference position from the TV 100, the distance from the TV to the reference position and the face of the viewer recognized using the image data are registered in advance. The distance from the television to the viewer is calculated using the ratio with the viewer's face. The calculation of the distance to the subject using the image data acquired by the first camera and the second camera is realized by a known stereo measurement process. Therefore, the details of the stereo measurement process will not be repeated here.

  Based on the data representing the center calculated by the position information calculation unit 514, the angle calculation unit 518 determines the viewing from the normal direction of the television 100 and the reference position from the reference position defined in advance for the television 100. A line-of-sight angle formed between the direction to the person is calculated. Preferably, the angle calculation unit 518 calculates an angle formed between the direction relative to the viewer and the normal direction from the center of the optical axis of the camera 150 as the viewing angle. Preferably, the angle calculation unit 518 calculates a vertical component and a horizontal component of the line-of-sight angle, respectively.

  In another aspect, angle calculation unit 518 calculates a line-of-sight angle centered on each camera when television 100 has the first camera and the second camera. That is, the angle calculation unit 518 calculates the viewing angle from the central axis of the television 100 based on the first distance and the second distance calculated by the distance calculation unit 516.

  The image quality control unit 520 adjusts the image quality of the video displayed on the liquid crystal display 130 based on the control data corresponding to the line-of-sight angle calculated by the angle calculation unit 518. Here, the control data refers to parameters defined in advance for controlling the display of video on the liquid crystal display 130. As will be described later, this parameter is data for adjusting, for example, contrast value, brightness, color tone, gamma characteristic, and other image quality.

  In another aspect, the image quality control unit 520 identifies the face region having the maximum area calculated by the area calculation unit 508 when the number of extracted face regions is plural. The image quality control unit 520 is further displayed on the liquid crystal display 130 with the angle formed between the direction corresponding to the viewer corresponding to the face area having the maximum area from the reference position and the normal direction as the viewing angle. Adjust the image quality of the recorded image.

  Further, the image quality control unit 520 may adjust the image quality in units of pixels of the liquid crystal display 130. For example, the pixels constituting the area of 1 square inch are grouped into one group. The distance between each group and the viewer is calculated. This distance can be calculated based on, for example, a distance (hereinafter referred to as a reference distance) from a group of pixels located at the center of the display area of the liquid crystal display 130 (ie, a group through which the central axis passes) to the viewer.

  That is, the reference distance is calculated based on the size of an image acquired by previously shooting a viewer at a standard position where the distance is known and an image acquired by shooting again at the time of viewing. . Similarly, the distance between the group of pixels located in the center and the group of pixels subject to image quality control is easily calculated. Alternatively, a distance calculated in advance according to the size of the liquid crystal display 130 may be held.

  Thereby, the distance from each group to the viewer is calculated. The parameter for adjusting the image quality and the assumed distance from the liquid crystal display 130 to the viewer are associated with each other and stored in the memory 112. The parameter is specified when the distance is actually calculated. Based on the parameter, the image quality of the group of pixels corresponding to the distance is adjusted. In this way, the image quality can be corrected according to the position of the display area of the liquid crystal display 130. Therefore, in a television in which the size of the liquid crystal display 130 is several tens of inches, the image quality of pixels located at both ends of the liquid crystal display 130 is corrected, so that a clearer image is displayed.

  The data structure of the television 100 will be described with reference to FIG. FIG. 6 is a diagram conceptually showing one mode of data storage in memory 112. The memory 112 includes a table 600. The table 600 has control data for controlling the display of video on the liquid crystal display 130.

  Specifically, the table 600 includes areas 610 to 650 for storing each control data. The line-of-sight angle is stored in area 610. In the example shown in FIG. 6, the line-of-sight angle, which is a control category, is defined every ± 10 °, for example. The contrast value is stored in area 620. The brightness is stored in area 630. Data for controlling the color tone is stored in area 640. Data for adjusting the gamma characteristic is stored in area 650. The data stored in the areas 610 to 650 are associated with each other. Therefore, when the line-of-sight angle indicated in the area 610 is specified, the control data (areas 620 to 650) associated with the line-of-sight angle is specified.

  For example, when the calculated line-of-sight angle is 10 °, the contrast value is set to 1.1 times the reference value. The brightness is set to 1.1 times the reference value. The color tone is also set to 1.1 times the reference value. The gamma characteristic is also set to 1.1 times the reference value. Here, the coefficient multiplied by the reference value in order to adjust the image quality is not limited to that shown in FIG. In the example illustrated in FIG. 6, the reference value for each control data is configured to use the same reference value for any viewer, but is not limited to such a configuration. That is, a different value for each viewer may be used as the reference value.

  Further, the symbol “±” in the line-of-sight angle specifies the position in the left and right regions with reference to the central axis of the television 100. Therefore, the sign + may be set for the position on the right side of the central axis, or vice versa. In addition, in the case where the television 100 can realize image quality adjustment by the horizontal viewing angle and the vertical viewing angle, another table having the same contents as the table 600 is provided. That is, control data set in advance for each of the horizontal viewing angle and the vertical viewing angle is prepared in the memory 112.

  A control structure of television 100 will be described with reference to FIGS. FIG. 7 and FIG. 8 are flowcharts showing the procedure of processing executed by CPU 110 realizing television 100, respectively.

  In FIG. 7, in step S <b> 710, CPU 110 of television 100 outputs a shooting instruction for a viewer existing in a predetermined location to television 100. When the CPU 110 outputs such an instruction to the camera 150, the camera 150 executes a predetermined shooting operation according to a preset shooting mode. In this case, for example, in order to prepare for a case where the illumination of the room 10 as shown in FIG. 3 is not sufficient, a configuration in which a light emission instruction is output to a light emitting unit (not shown) in order to clearly capture the viewer 12 is further provided. You may have.

  When the camera 150 executes the photographing process, the output image signal is stored in the memory 152. The CPU 110 executes predetermined image processing on the data. The image processing is, for example, binarization processing, density processing, edge enhancement processing, and the like.

  In step S720, CPU 110 executes the image processing described above. In step S730, CPU 110 calculates a feature amount from the image data of the viewer stored in memory 152 in accordance with a preset process.

  In step S740, CPU 110 associates the calculated feature quantity with data for identifying the viewer, and stores it in an area secured in memory 112. The data for specifying the viewer is acquired by the television 100 by receiving a signal including character information transmitted from a remote control signal by the light receiving unit 106 or by inputting characters to the operation unit 108, for example.

  Referring to FIG. 8, in step S <b> 810, CPU 110 detects that an image signal output from camera 150 has been written in memory 152. In step S820, CPU 110 performs preset image processing on the data stored in memory 152, and further extracts a face area.

  In step S830, CPU 110 calculates position information of the face area. In step S840, CPU 110 calculates the viewing angle of the viewer with respect to television 100 based on the positional information and data prepared in advance that specifies the positional relationship between camera 150 and liquid crystal display 130.

  In step S850, CPU 110 reads control data for image quality adjustment from memory 112 in accordance with the line-of-sight angle. In step S860, CPU 110 outputs an image quality adjustment command signal based on the read control data to image quality adjustment circuit 124. The image quality adjustment circuit 124 executes image quality adjustment processing defined based on the signal. When the adjusted signal is sent from the image quality adjustment circuit 124 to the OSD circuit 126, the liquid crystal display 130 displays the image after the image quality adjustment.

  As described above, television 100 according to the present embodiment detects the position of the viewer and calculates the line-of-sight angle as information for specifying the positional relationship between the viewer and television 100. The television 100 adjusts the image quality of the video displayed on the liquid crystal display 130 based on the control data defined in advance according to the viewing angle. Thus, even when the viewer is not viewing from the position directly in front of the liquid crystal display 130, the viewer can view the video with the image quality corrected according to the viewing position.

  In addition, the television 100 can calculate a horizontal viewing angle and a vertical viewing angle as the viewing angles. In this case, the image quality is corrected based on control data defined in advance according to each line-of-sight angle. Accordingly, even when the viewer is positioned below the horizontal plane with respect to the display of the television 100 (for example, when lying down and viewing), the television 100 can display the image quality according to the viewer's position. Can be corrected. Also in this case, the viewer can appreciate a clear video.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. Television 100 according to the present embodiment differs from the above-described embodiment in that it has a function of prohibiting image adjustment processing when the faces of a plurality of viewers are recognized. This function is realized by the CPU 110. The hardware configuration of the television according to the present embodiment is the same as the hardware configuration of television 100 shown in FIG. These functions are the same except for the functions newly realized by the CPU 110. Therefore, description of the same function will not be repeated.

  FIG. 9 is a flowchart showing a procedure of processing executed by CPU 110 that realizes the television according to the present embodiment. In step S910, CPU 110 determines whether or not a plurality of face areas have been extracted based on the face area data extracted by face area extraction unit 502. If CPU 110 determines that a plurality of face regions have been extracted (YES in step S910), the process proceeds to step S920. If not (NO in step S910), the process proceeds to step S930.

  In step S920, CPU 110 outputs a command prohibiting correction of the image quality of the video displayed on liquid crystal display 130 to image quality adjustment circuit 124. When this command is output, the video signal input to the image quality adjustment circuit 124 is output to the OSD circuit 126 as it is without any processing. In step S930, CPU 110 calculates position information of one extracted face area. Thereafter, the line-of-sight angle is calculated (step S840), and image quality adjustment according to the line-of-sight angle is executed (steps S850 and S860).

  As described above, the television 100 in another aspect does not perform image quality correction when a plurality of viewers are detected. Thus, by performing correction according to the position of one of the viewers, it is possible to prevent an image that cannot be appreciated by other viewers from being displayed.

<Third Embodiment>
Hereinafter, a third embodiment of the present invention will be described. The television according to the present embodiment is different from the above-described embodiments in that it has an image quality adjustment function according to the viewer closest to the central axis of the liquid crystal display 130 when a plurality of viewers are detected. Such a function is realized by the CPU 110 shown in FIG. Other hardware configurations are the same as those included in the television 100 according to the first embodiment. Therefore, description thereof will not be repeated.

  FIG. 10 is a flowchart showing a procedure of processing executed by CPU 110 realizing television 100 according to the third embodiment of the present invention.

  In step S1110, CPU 110 determines whether or not a plurality of face areas have been extracted based on the face area data extracted by face area extraction unit 502. If CPU 110 determines that a plurality of face regions have been extracted (YES in step S1110), the process proceeds to step S1020. If not (NO in step S1010), the process proceeds to step S1030.

  In step S1020, CPU 110 specifies the viewer closest to the central axis of liquid crystal display 130 based on the image data of the face area. That is, the CPU 110 calculates the distance between the center part (for example, the center part of the eyes) of each recognized viewer's face and the center part in the area reserved for image processing. The viewer giving the minimum value is specified as the viewer closest to the central axis.

  In step S1030, CPU 110 calculates position information of the viewer's face area. Thereafter, the CPU 110 calculates the line-of-sight angle (step S840) and executes the same image adjustment processing as described above (steps S850 and S860).

  As described above, when the television according to the present embodiment detects viewing by a plurality of viewers, the television adjusts image quality according to viewers closer to the center of the television. In this way, extreme image quality correction is prevented, and image quality correction that can be sufficiently viewed by viewers other than the viewer from the center is realized. Thereby, any viewer can enjoy viewing the video.

<Fourth embodiment>
Hereinafter, a fourth embodiment of the present invention will be described. The television according to the present embodiment is different from the television according to each of the embodiments described above in that it has an image quality adjustment function that takes into account the distance from the display in addition to the line-of-sight angle.

  That is, liquid crystal televisions vary widely, for example, from a size of several tens of inches to a size of several tens of inches, depending on the size of the display unit. In this case, in a liquid crystal television with a small display size, for example, the distance between the left end and the right end of the television is not so different, and thus the influence of viewing due to the difference in the distance can be ignored. However, according to a liquid crystal display having a size of several tens of inches, the difference between the right end and the left end also increases accordingly, and thus the distance between the television and the viewer also differs greatly. Therefore, for example, when the viewer is present at the left end and is viewing the television from that position, the left end image on the display of the television 100 can be clearly seen, but the right end image cannot be clearly seen. There is also a possibility. Therefore, in order to consider such a difference in the size of the television, it is preferable to consider the distance between the viewer and the television.

  Therefore, with reference to FIG. 11, the positional relationship between the television and the viewer according to the present embodiment will be described. FIG. 11A is a diagram showing a positional relationship in the case where the size of the liquid crystal display is small (for example, several tens of inches) and the influence of display due to the size of the television can be ignored. In FIG. 11B, the size of the liquid crystal display of the television 1120 is large (for example, 32 inches, 42 inches, etc.), and the influence due to the difference in the distance from the left and right positions of the television 1120 to the viewer is ignored. It is a case where it cannot be done. The television according to this embodiment can be applied to a television 1120 as shown in FIG.

  Referring to FIG. 11A, regarding the distance between television 1110 and viewer 1100, the distance from the right end of television 1110 to viewer 1100 is distance 1132. On the other hand, the distance from the left end of the television 1110 to the viewer 1100 is a distance 1130. Here, generally, the distance between the television 1110 and the viewer 1100 (3 to 5 meters in the case of a conventional CRT (Cathod Ray Tube) type television) is as shown in FIG. In television, the difference between distance 1130 and distance 1132 is negligible.

  On the other hand, with reference to FIG. 11B, the distance 1140 between the left end of the television 1120 and the viewer 1100 and the distance 1142 from the right end of the television 1120 to the viewer 1100 depend on the size 1122 of the television 1120. A considerable gap can occur. Therefore, even if the image quality adjustment according to the viewing angle is performed as described above, the video displayed on the right side of the television 1122 may not be clearly visible.

  Therefore, in order to adjust the image quality in consideration of such a difference in distance, it is desirable that the television according to the present embodiment has each control data corresponding to the distance in advance.

  Next, the data structure of the television according to the present embodiment will be described with reference to FIG. FIG. 12 is a diagram illustrating an aspect of storing control data in memory 112 provided in the television according to the present embodiment. The memory 112 includes a table 1200 having control data defined according to the distance from the television. The table 1200 includes areas 1210 to 1240 for storing each control data. The line-of-sight angle is stored in area 1210. Data representing the distance from television 100 to the viewer is stored in area 1220. The contrast value is stored in area 1230. The brightness is stored in area 1240. The data stored in the areas 1210, 1230, and 1240 correspond to the data stored in the areas 610, 620, and 630, for example, as shown in FIG. Therefore, description thereof will not be repeated here.

  Further, regarding the area 1220, data representing distances based on the standard distance is stored. Here, the standard distance refers to a distance defined in advance according to the size of the television. This distance corresponds to the distance between a position defined in advance for registering the viewer 12 in the television 100 and the television, for example, as indicated by a dotted line 430 in FIG. Using such a distance as a reference, whether the distance is close or close to the distance is divided into preset categories, and each is defined as a contrast value (region 1230) or brightness (region 1240). Can do. In this way, image quality adjustment can be performed in consideration of the distance (region 1220) in addition to the viewing angle (region 1210).

  Therefore, with reference to FIG. 13, a control structure of the television according to the present embodiment will be described. FIG. 13 is a flowchart showing a procedure of processing executed by CPU 110 that realizes the television according to the present embodiment.

  In step S1310, CPU 110 calculates each distance from the center and end (right end and left end) of the liquid crystal display included in the television to the viewer. This distance is calculated based on a known surveying method based on the positional relationship shown in FIG. 4, for example.

  In step S1320, CPU 110 refers to table 1200 and reads control data for image quality adjustment based on the calculated line-of-sight angle and each distance. After that, when the CPU 110 outputs an image quality adjustment command signal based on the control data (step S860), the image quality adjustment circuit 124 executes a process for correcting the contrast value or brightness based on the signal, and sends it to the OSD circuit 126. The processed video signal is output. As a result, the liquid crystal display 130 displays an image corrected based on the line-of-sight angle and the distance.

  As described above, the television according to the fourth embodiment of the present invention reflects the distance to the viewer in addition to the viewing angle in the adjustment of the image quality. Therefore, even when the distance between the viewer and the liquid crystal display 130 is significantly greater than the normal viewing distance, the viewer can enjoy viewing the video corrected according to the distance.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is applicable to, for example, liquid crystal televisions, liquid crystal monitors, and other liquid crystal display devices.

It is a figure showing the television 100 which concerns on the 1st Embodiment of this invention from the front. 2 is a block diagram showing a hardware configuration of television 100. FIG. 2 is a diagram illustrating a state where a television 100 is installed in a room 10. FIG. It is the figure which represented the room 10 from the upper part. It is a block diagram showing the structure of the function implement | achieved by CPU110. FIG. 3 is a diagram conceptually showing one mode of data storage in a memory 112. 5 is a flowchart (part 1) illustrating a procedure of processes executed by CPU 110 that implements television 100. 12 is a flowchart (No. 2) showing a procedure of processes executed by CPU 110 realizing television 100. It is a flowchart showing the procedure of the process which CPU110 which implement | achieves the television which concerns on the 2nd Embodiment of this invention is performed. It is a flowchart showing the procedure of the process which CPU110 which implement | achieves the television 100 which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the positional relationship of the television and viewer which concern on the 4th Embodiment of this invention. It is a figure showing the one aspect | mode of the storage of the control data in the memory 112 with which the television concerning the 4th Embodiment of this invention is provided. It is a flowchart showing the procedure of the process which CPU110 which implement | achieves the television which concerns on the 4th Embodiment of this invention is performed.

Explanation of symbols

  10 rooms, 11 chairs, 12, 402, 403, 404, 405 viewers, 100 televisions, 102 antennas, 300 remote control terminals, 310 viewing angles, 320 horizontal lines, 330 viewing lines.

Claims (14)

A liquid crystal display device,
A display for displaying images in the liquid crystal display area;
A camera attached to the display, which captures a subject and outputs an image signal;
Extracting means for extracting a face area of a viewer of the video based on the image signal;
First storage means for storing a first feature amount representing a face area of a viewer acquired in advance based on a first image signal from the camera, wherein the first feature amount is the camera Obtained by photographing of the viewer at a predetermined position on the optical axis center of
In response to display of the video on the display, shooting control means for outputting an instruction to shoot the viewer of the video;
The viewer is registered in the liquid crystal display device based on the first feature amount and the second feature amount calculated using the second image signal acquired in response to the instruction. An authentication means for confirming whether or not,
Means for extracting feature points of the viewer based on the second image signal when the viewer is registered in the liquid crystal display device;
Means for calculating a feature amount of the viewer based on the feature points;
Means for calculating position information for specifying the position of the face area of the viewer based on the feature amount;
Based on the first feature value, the second feature value, and the position information, a gap is formed between the direction from the optical axis center of the camera to the viewer and the normal direction of the liquid crystal display region. An angle calculating means for calculating the angle as a gaze angle;
Second storage means for storing control data defined in advance according to each of the plurality of line-of-sight angles in order to adjust the image quality of the video displayed on the display;
A liquid crystal display device comprising: control means for adjusting an image quality of an image displayed on the display based on the control data corresponding to the line-of-sight angle calculated by the angle calculation means. A liquid crystal display device,
Display means for displaying an image in a liquid crystal display area;
Acquisition means for acquiring an image signal generated based on photographing of a subject;
Extracting means for extracting a face area of a viewer of the video based on the image signal;
Position information calculating means for calculating position information for specifying the position of the face area of the viewer in the image based on the image signal;
Based on the position information, a line-of-sight angle formed between a normal direction of the liquid crystal display region from a reference position defined in advance in the liquid crystal display device and a direction from the reference position to the viewer is calculated. An angle calculation means;
Storage means for storing each control data preliminarily defined according to each of the plurality of line-of-sight angles in order to define image quality adjustment of the video displayed on the display means;
A liquid crystal display device comprising: control means for adjusting an image quality of an image displayed on the display means based on the control data corresponding to the line-of-sight angle calculated by the angle calculation means.   The liquid crystal display device according to claim 2, wherein the acquisition unit includes an imaging unit that images a subject and outputs an image signal. The imaging means is attached to the display means,
The liquid crystal display device according to claim 3, wherein the angle calculation unit calculates an angle formed between a direction with respect to the viewer and the normal direction from an optical axis center of the imaging unit as the visual line angle. .   The liquid crystal display device according to claim 3, wherein the angle calculation unit calculates a vertical component and a horizontal component of the line-of-sight angle. In response to display of the video by the display means, shooting control means for outputting an instruction to shoot a viewer of the video;
Feature amount calculating means for calculating the feature amount of the face area extracted by the extracting means;
Calculated using a first feature amount representing a viewer's face area acquired in advance based on a first image signal from the imaging means and a second image signal acquired in response to the instruction. Authentication means for confirming whether or not the viewer is registered in the liquid crystal display device based on the second feature amount,
The liquid crystal display device according to claim 3, wherein the position information calculation unit calculates the position information in an image based on the second image signal when the viewer is registered in the liquid crystal display device. The acquisition means includes
First imaging means for photographing a subject and outputting a first image signal;
And a second imaging unit that images the subject and outputs a second image signal, and each positional relationship of the first imaging unit and the second imaging unit with respect to the display unit is defined in advance. And
The extraction means extracts the viewer's first face area based on the first image signal and the viewer's second face area based on the second image signal;
The position information calculating means calculates first position information for specifying a center of the first face area and second position information for specifying a center of the second face area;
The liquid crystal display device performs stereo measurement processing based on the predetermined positional relationship, the first position information, and the second position information, so that the first imaging unit performs the stereo measurement process. Distance calculating means for calculating a first distance to the viewer and a second distance from the second imaging means to the viewer;
The liquid crystal display device according to claim 2, wherein the angle calculation unit calculates the line-of-sight angle based on the first distance and the second distance. A calculation means for calculating the number of face regions extracted by the extraction means;
The liquid crystal display device according to claim 2, wherein the control unit prohibits the adjustment of the image quality when the number of the face regions is plural. Calculating means for calculating the number of face regions extracted by the extracting means;
An area calculating means for calculating the area of the face region;
The control means includes
When the number of the face areas is plural, the face area having the largest area calculated by the area calculating means is specified, and the viewing / listening corresponding to the face area having the largest area from the reference position 3. The liquid crystal display device according to claim 2, wherein the image quality is adjusted with an angle formed between a direction to a person and the normal direction as the line-of-sight angle. The extraction means includes a plurality of elements for accumulating data corresponding to the face area,
The liquid crystal display device according to claim 9, wherein the area calculation unit calculates the area of the face region by calculating the number of the elements in which data corresponding to the face region is stored. The position information calculation means includes
Means for extracting feature points of the viewer based on the image signal;
Means for calculating a feature amount of the viewer based on the feature points;
The liquid crystal display device according to claim 2, further comprising: a unit that calculates the position information based on the feature amount. Feature amount storage means for storing a first feature amount corresponding to the size of the viewer's face at the position acquired in advance by photographing the viewer at a predetermined position with respect to the liquid crystal display device When,
Feature amount calculating means for calculating a second feature amount corresponding to the size of the viewer's face of the video based on the face area extracted by the extracting means when the display means is displaying a video. When,
A distance calculation means for calculating a distance between the viewer and the liquid crystal display device by comparing the first feature value and the second feature value;
The liquid crystal display device according to claim 2, wherein the angle calculation unit calculates the line-of-sight angle based on the distance calculated by the distance calculation unit. The display means includes a plurality of display elements,
The control means adjusts the image quality by controlling driving of each display element based on the distance calculated by the distance calculation means and the line-of-sight angle calculated by the angle calculation means. 12. A liquid crystal display device according to item 12.   The liquid crystal display device according to claim 2, wherein the acquisition unit includes a signal input unit that receives an input of the image signal.

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