JP2019070850A - Display and method for controlling the same - Google Patents

Abstract

To provide an image display device that has a plurality of light sources in which light emission luminance can be individually changed, and controls the light emission luminance of the light sources according to images of areas corresponding to the light sources, and prevent a halo effect and flicker caused by movement of an object image, such as a cursor.SOLUTION: An image display device comprises light emitting means that has a plurality of light sources in which light emission luminance can be individually controlled; display means that displays an image on a screen by modulating light from the light emitting means; and control means that controls the light emission luminance of the light sources according to images in areas on the screen corresponding to the plurality of light sources. When a difference between an image in an object frame determining the light emission luminance and an image in a frame prior to the object frame is caused by movement of a predetermined object, the control means prevents a change in light emission luminance of the light source corresponding to the area of the image brighter than a previous frame in the object frame, from the light emission luminance of the light source corresponding to the area in the previous frame.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display apparatus and a control method thereof.

  In the liquid crystal display device, a backlight is configured by a plurality of light sources capable of individually changing the light emission luminance, and the light emission luminance and the liquid crystal of each light source are displayed for each area based on the image to be displayed on the screen There is a technique for controlling the transmittance (for example, Patent Document 1). According to this technique, it is possible to suppress the black floating of the dark part of the image and to improve the contrast.

Japanese Patent Laid-Open No. 2002-99250

  However, it is necessary to faithfully reproduce an input image in a display for image editing and a display for color management used for confirmation of a design of a poster or a web. In an image output from a personal computer, an image of an object such as a mouse cursor (hereinafter referred to as a cursor) may be superimposed on an original image to be faithfully reproduced and displayed. When such an image is input, if the above-described control of changing the brightness of the backlight and the transmittance of the liquid crystal on the basis of the image signal for each area is applied, the brightness of the cursor is faithfully reproduced. As a result, when the cursor overlaps with the dark area in the original image, the light source corresponding to the area where the cursor exists is brightly lit in an attempt to accurately express the brightness of the cursor. Then, when the light source corresponding to the area where the cursor exists is brightly lit, the light leaks to the surrounding area (described with the halo effect and the present specification), and there is a problem that the user sees as an obstacle. FIG. 11 shows how the cursor of high brightness (white) moves in the dark area of the original image. When the light source corresponding to the area where the cursor is present is brightly lit, the halo effect can be seen around the area where the cursor is present. In addition, as the cursor moves from the position A to the position B in FIG. 11, the halo effect is also moved so that the movement is frequently generated, which causes the observer to feel flicker. .

  According to the present invention, an image display apparatus having a plurality of light sources capable of individually changing light emission luminance and controlling the light emission luminance of each light source according to an image of a region corresponding to each light source The purpose is to suppress the halo effect and flicker caused by movement.

The present invention relates to a light emitting means having a plurality of light sources capable of individually controlling light emission luminance;
Display means for displaying an image on a screen by modulating light from the light emitting means;
Control means for controlling the light emission luminance of each light source according to the image of the area on the screen corresponding to each of the plurality of light sources;
Equipped with
When the difference between the image of the target frame for which the light emission luminance is to be determined and the image of the frame earlier than the target frame is due to the movement of a predetermined object, the control means is an image brighter than the previous frame in the target frame It is an image display device characterized by suppressing a change from the light emission luminance of the light source corresponding to the area of the past frame of the light emission luminance of the light source corresponding to the area of.

The present invention relates to a light emitting means having a plurality of light sources capable of individually controlling light emission luminance;
Display means for displaying an image on a screen by modulating light from the light emitting means;
A control method of an image display apparatus comprising:
According to the image of the area on the screen corresponding to each of the plurality of light sources, there is a control step of controlling the light emission luminance of each light source,
In the control step, when the difference between the image of the target frame for which the light emission luminance is to be determined and the image of the previous frame from the target frame is due to the movement of a predetermined object, the image brighter than the past frame in the target frame A control method of an image display apparatus characterized by suppressing a change from the light emission luminance of the light source corresponding to the area of the past frame of the light emission luminance of the light source corresponding to the area of.

  According to the present invention, an object such as a cursor is provided in an image display device having a plurality of light sources capable of individually changing light emission luminance and controlling the light emission luminance of each light source according to an image of a region corresponding to each light source. It is possible to suppress the halo effect and the flicker caused by the movement of the image.

Functional block diagram of the image display device according to the first embodiment Example of acquired feature amount for each block in the first embodiment Example of the feature stored in the feature storage unit in the first embodiment An example of a table showing the relationship between the number of pixels whose luminance has changed and the update mode in the first embodiment Look-up table for determining backlight brightness in the first embodiment Example of backlight brightness per block in the first embodiment Functional block diagram of the image display apparatus according to the second embodiment Example of backlight brightness per block in the second embodiment Functional block diagram of the image display device according to the third embodiment Relationship between update mode, scene determination result, and update block selection method of the third embodiment Example of task image Functional block diagram of the image display device according to the fourth embodiment

Example 1
Embodiments of the present invention will be described with reference to the drawings.
The image display apparatus according to the first embodiment obtains the number of pixels whose luminance is changing among the pixels on the entire screen (hereinafter, referred to as movement amount). The image display device determines whether the amount of movement is due to the movement of the cursor based on whether the amount of movement is equal to or less than the maximum number of pixels that changes as the object supporting the user operation such as the mouse cursor moves. To detect cursor movement. The image display apparatus determines that the cursor does not exist in the current frame from the feature of the current frame and the stored feature of the past frame at the timing when the cursor movement is detected. Generate The image display apparatus determines the luminance of the backlight from the generated feature amount. As a result, in the image display apparatus that performs local dimming for contrast improvement, it is possible to suppress the halo effect and flicker when the high-brightness cursor moves in the dark area in the original image. The first embodiment will be described in detail below.

FIG. 1 shows a functional block diagram of the image display apparatus in the first embodiment. The image display device of FIG. 1 includes a liquid crystal panel unit 1, a backlight module unit 2, a luminance change detection unit 3, a frame buffer 4, a feature amount detection unit 5, a feature amount storage unit 6, an update mode determination unit 7, and a backlight luminance The determination unit 8, the luminance estimation unit 9, and the correction coefficient calculation unit 10 are included. The image display apparatus of FIG. 1 further includes a correction coefficient multiplication unit 11 and a Limit unit 12.

The liquid crystal panel unit 1 includes a liquid crystal driver, a control substrate that receives an input image signal and controls the liquid crystal driver, and a liquid crystal panel. The liquid crystal panel unit 1 is a display panel that displays an image on a screen by modulating light from the backlight module unit 2. In this embodiment, an example in which the present invention is applied to a transmission type image display device provided with a liquid crystal panel as a display panel is described, but the application target of the present invention is not limited to the liquid crystal display device. The image display device may be any image display device having an independent light source. For example, the image display device may be a reflective liquid crystal display device. Further, the image display device may be a MEMS shutter type display using a MEMS (Micro Electro Mechanical System) shutter instead of a liquid crystal element.

  The backlight module unit 2 includes a light emitting element for backlight, a control circuit that controls light emission of the light emitting element, and an optical unit for diffusing light from the light emitting element. The backlight is divided into a plurality of regions, one or more light emitting elements are included in each region, and light emission is controlled in units of each region. An area serving as a unit of light emission control is referred to as a "light source" in the present specification. That is, the backlight comprises a plurality of light sources capable of individually controlling the light emission luminance, and each light source is constituted by a set of one or more light emitting elements. The number of area divisions of the backlight is m horizontal and n vertical (m and n are integers). In the present embodiment, the number of area divisions of the backlight is 8 horizontal × 6 vertical. The backlight module unit 2 receives the luminance determined by the backlight luminance determination unit 8 and drives each light source so that the emission luminance of each light source becomes the received luminance.

  The luminance change detection unit 3 reads out the image data stored in the frame buffer 4 and compares the image data of the current frame with the image data of a past frame (in the present embodiment, a frame one frame before the current). , Pixels whose luminance has changed are detected and counted. The luminance change detection unit 3 outputs the counted value to the update mode determination unit 7. The image of the past frame to be compared with the image of the current frame is not limited to the frame one frame before the current one, and may be the image of the frame two frames before the present one.

  The frame buffer 4 stores image data of one frame. The image data of the past frame for which the comparison has ended is deleted by the luminance change detection unit 3, and the image data of the current frame for which the comparison has ended is stored.

  The feature amount detection unit 5 divides the image into blocks corresponding to the respective light sources of the backlight, and detects the feature amount for each block. The feature amount detection unit 5 sends the detected feature amount to the feature amount storage unit 6 and the backlight luminance determination unit 8 in the subsequent stage. In the present embodiment, the feature amount detection unit 5 detects the maximum value of RGB pixel values for each block.

  This will be described using the example of the input image of FIG. When the cursor of FIG. 11 is at the position of A and at the position of B, the maximum pixel value for each block is shown in FIGS. 2 (a) and 2 (b). The tone value of the pixels constituting the image of the cursor is set to 255. Since the cursor exists at the position of the coordinates (3, 2) in FIG. 2A and the coordinates (5, 2), (6, 2) in FIG. 2B, 255 as the maximum pixel value of the above coordinates. The value of is detected.

  The feature storage unit 6 stores the feature of each block detected by the feature detection unit 5. The storage timing is the timing at which the determination result of the update mode determination unit 7 described later is received. The update mode determination unit 7 sets one of the update modes of update mode 0, update mode 1, and update mode 2.

In the update mode 0, the feature storage unit 6 updates the stored feature for all blocks with the feature of the current frame detected by the feature detection unit 5.

  In the update mode 1, the feature amount storage unit 6 stores the feature amounts stored only for the blocks whose feature amounts of the current frame detected by the feature amount detection unit 5 are reduced with respect to the stored feature amounts. The feature amount of the current frame detected by the feature amount detection unit 5 is updated. Specifically, the feature storage unit 6 reads the maximum pixel value stored for each block, and compares the maximum pixel value detected by the feature detection unit 5 for the current frame for each block. For a block whose maximum pixel value of the current frame is smaller than the stored maximum pixel value, the feature amount storage unit 6 updates the stored maximum pixel value with the maximum pixel value of the current frame. On the other hand, the feature amount storage unit 6 does not update the stored maximum pixel value for a block having the maximum pixel value of the current frame and stored therein.

  In the update mode 2, the feature storage unit 6 does not update the stored feature for all blocks.

  When receiving the determination result of update mode 0 from the update mode determination unit 7, the feature amount storage unit 6 updates the feature amount as follows. For example, the case where the maximum value for each block changes from FIG. 2 (a) to FIG. 2 (b) will be described. Since the maximum pixel value of the block at coordinate (3, 2) is 255 in FIG. 2A but becomes 0 in FIG. 2B, when changing from FIG. 2A to FIG. 2B , The maximum pixel value is low. Therefore, the feature amount storage unit 6 updates the maximum pixel value stored for the block at the coordinates (3, 2) with the maximum pixel value of FIG. 2B. On the other hand, since the maximum pixel value of the block (5, 2) changes from 0 to 255 and is large, the feature amount storage unit 6 updates the maximum pixel value stored for this block. do not do. The same applies to the block of coordinates (6, 2). Since the other pixels have the same maximum pixel value in FIGS. 2A and 2B, the feature storage unit 6 does not update the maximum pixel values stored for these blocks. Thus, when the feature stored in the past frame is as shown in FIG. 2A and the feature detected in the current frame is as shown in FIG. 2B, the feature shown in FIG. The updated result is shown in FIG.

When the feature storage unit 6 receives the determination result of the update mode 0 from the update mode determination unit 7, the maximum pixel values of all the stored blocks are detected by the feature detection unit 5 for the current frame. Update with pixel value.
When receiving the determination result of update mode 2 from the update mode determination unit 7, the feature amount storage unit 6 does not update the maximum pixel values of all the stored blocks.
The feature storage unit 6 outputs the stored feature in response to the request from the backlight luminance determination unit 8.

  The update mode determination unit 7 determines the feature amount update mode of the feature amount storage unit 6 according to the detection result of the luminance change detection unit 3. Specifically, the update mode determination unit 7 sets the update mode 1 when the number of pixels whose luminance has changed is equal to or less than the threshold. That is, only the block in which the feature amount (maximum pixel value) decreases is set to the update mode in which the feature amount is updated. This threshold is determined based on the number of pixels whose luminance changes as the cursor moves.

  The relationship between the number of pixels in which the luminance has changed and the update mode in this embodiment is shown in FIG. In this embodiment, the number of pixels of the input image is set to 1920 horizontal pixels × 1080 vertical pixels. It is assumed that the number of pixels of the image of the cursor is 200 or less. When the cursor moves, the brightness may change between the move source and the move destination.

When there are pixels whose luminance has changed and the number thereof is 200 × 2 = 400 pixels or less, the update mode determination unit 7 determines that the cursor is moved, and sets the update mode 1. In this case, the stored feature amount is not updated for the block having the large feature amount, and the feature amount stored only for the block having the low feature amount is updated. This suppresses the increase in luminance in the block to which the cursor is moved, and the luminance decreases in the block from which the cursor is moved. Therefore, the halo effect is suppressed, and the occurrence of flicker due to the movement of the halo along with the cursor movement is suppressed.

If there are pixels whose luminance has changed and the number exceeds 400 pixels, the update mode determination unit 7 determines that the input image is a still image but the image has changed or the input image is a moving image. , Update mode 0 is set. In this case, the stored feature amounts are updated for all blocks. Therefore, the luminances of all the blocks correspond to the image of the current frame, and the image display is performed with high contrast.
When the number of pixels in which the luminance has changed is 0, the update mode determination unit 7 determines that there is no change in the image in the previous and subsequent frames, sets the update mode 2 and prevents the stored feature amount from being updated.
The update mode determination unit 7 sends the information on the update mode determined as described above to the feature amount storage unit 6 and the backlight luminance determination unit 8.

  The backlight luminance determination unit 8 determines the luminance of the backlight for each light source from the feature amount detected by the feature amount detection unit 5 or the feature amount stored by the feature amount storage unit 6. It is determined based on the update mode determined by the update mode determination unit 7 whether the backlight luminance is to be determined using either the feature amount detected by the feature amount detection unit 5 or the feature amount stored by the feature amount storage unit 6 Be done. In the case of the update mode 1 or the update mode 2, the backlight luminance determination unit 8 calculates backlight luminance from the feature amount stored by the feature amount storage unit 6. In the case of the update mode 0, the backlight luminance determination unit 8 calculates using the feature amount detected by the feature amount detection unit 5.

  The backlight luminance determination unit 8 is based on the feature amount of each block (the maximum pixel value in the present embodiment) and the information on the correspondence between the backlight luminance and the feature amount stored as a look-up table. The light emission luminance of the light source corresponding to the block is determined. An example of the look-up table is shown in FIG. FIG. 5 shows the maximum pixel value as an input on the horizontal axis and the backlight luminance as an output on the vertical axis. A backlight luminance of 0 indicates a state in which the light source is not lit, and a backlight luminance of 100 indicates a state in which the light source is lit at maximum brightness.

  The light emission luminance for each light source, which is determined with reference to the look-up table of FIG. 5 when the feature amount (maximum pixel value) for each block is shown in FIG. As shown in FIG. 6, when the cursor is moved as shown in the image of FIG. 11, the luminance of the light source corresponding to the block (3, 2) from which the cursor is moved is determined to be zero. Also, the luminance of the light source corresponding to the blocks (5, 2) and (6, 2) to which the cursor is moved is determined to be zero. From this, both the halo effect due to the presence of a predetermined object (here, the mouse cursor as an auxiliary object for assisting the user operation) composed of a high brightness image and the flicker (movement of the halo) accompanying the movement of the object Can be suppressed.

  The backlight luminance determination unit 8 sends the backlight luminance for each light source determined as described above to the luminance estimation unit 9 and the backlight module unit 2. Although the luminance is determined using the look-up table in the present embodiment, it may be determined using a calculation formula.

The brightness estimation unit 9 estimates the brightness of light incident on the liquid crystal panel unit 1 by lighting of the backlight module unit 2. In the present embodiment, the luminance estimation unit 9 estimates the luminance at the central point of each block. The brightness estimation unit 9 reads out from the memory information on the intensity of leaked light to the surrounding area when the light source of the backlight corresponding to each block is turned on. In the present embodiment, information on the intensity of leaked light is stored in the memory as an attenuation coefficient at the central point of each block. The brightness estimation unit 9 estimates the brightness by calculation of multiplying the attenuation coefficient read from the memory and the backlight brightness of each light source determined by the backlight brightness determination unit 8. The luminance estimation unit 9 sends the estimated luminance to the correction coefficient calculation unit 10.

The correction coefficient calculation unit 10 obtains a correction coefficient for correcting the image data from the estimation result of the luminance at the central point of each block calculated by the luminance estimation unit 9. The correction coefficient is a coefficient used for calculation of extending pixel values in order to compensate for the reduction in display luminance due to the reduction in backlight luminance. In a block in which the luminance of the backlight is high and the display luminance is higher than the target luminance, the correction coefficient calculation unit 10 obtains a correction coefficient so that the correction to lower the luminance is performed on the pixel value. The correction coefficient Gpn can be obtained by the following equation, where Lpn is the estimated luminance of the central point of a block, Lt is the target luminance after expansion or adjustment with the correction coefficient, and Gpn is the correction coefficient of the central point. .

Gpn = Lt / Lpn

The target luminance Lt is determined based on the peak luminance of the screen. In addition, since the brightness estimation is performed for discrete center points, the correction coefficient corresponding to the pixel between the center points of the block is the estimated brightness at the center point of the periphery and the position with the center point of the periphery Calculated by interpolation based on the relationship

  The correction coefficient multiplication unit 11 corrects the image data by multiplying the image data of the corresponding pixel by the correction coefficient determined by the correction coefficient calculation unit 10. The correction coefficient multiplication unit 11 sends the corrected image data to the Limit unit 12.

  When the image data corrected by the correction coefficient multiplying unit 11 exceeds the input range of the liquid crystal panel unit 1, the Limit unit 12 corrects the image data so as to fall within the input range.

  The above is the details of the first embodiment. With the above configuration, when the difference between the image of the target frame for which the light emission luminance is determined and the image of the past frame is due to the movement of a predetermined object (cursor), a light source corresponding to the region of the image brighter than the past frame Changes in the light emission luminance of Even when a high brightness object image (cursor) moves in a dark area of the image, it is possible to prevent both the movement source block and the movement destination block from being brightly lit in response to the high brightness pixel value of the cursor. That is, since each light source can be made to emit light with backlight luminance in the state where the cursor is not present in the original image, it is possible to preferably achieve both improvement in contrast and suppression of the halo effect and flicker.

  In the present embodiment, the feature amount of the block to which the cursor is moved is not updated by keeping the feature amount calculated when the cursor is not present, thereby causing halos and flickers due to the high-brightness pixels constituting the cursor. Described how to suppress the occurrence of However, if the movement destination block of the cursor is a dark area of the image including the periphery, the display brightness of the cursor may be dark and the visibility of the cursor may be reduced. Therefore, the feature amount storage unit 6 obtains the feature amount of the block to which the cursor has moved and the average value of the feature amounts of the blocks of the past frame and the current frame, and the average value of the feature amounts of the block to which the cursor moves May be updated. By doing this, the visibility of the cursor is improved to the extent that the disturbing feeling is not noticeable. In the present embodiment, the light emission luminance of the light source corresponding to the area of the image brighter than the past frame in the target frame for which the light emission luminance is determined is not changed from the light emission luminance of the light source corresponding to the corresponding area of the past frame. good. Alternatively, by setting the emission brightness of the light source corresponding to the area of the bright image in the target frame to be lower than the emission brightness corresponding to the bright image, the change from the emission brightness of the light source corresponding to the area of the past frame May be suppressed.

(Example 2)
In the first embodiment, the feature amount when the cursor does not exist in the current frame is determined from the feature amount of the current frame and the feature amount of the past frame stored, and the display of the current frame is performed based on the feature amount. The backlight brightness to apply was determined. In the second embodiment, the backlight luminance when the cursor does not exist in the current frame is obtained from the backlight luminance determined from the feature amount of the current frame and the backlight luminance in the past. Thus, as in the first embodiment, in the image display apparatus that improves the contrast by local dimming according to the input image, both the halo effect and the flicker when the cursor of high brightness moves in the dark area of the image are suppressed. be able to.

  FIG. 7 shows a functional block diagram of the image display apparatus in the second embodiment. The image display apparatus of FIG. 7 includes a liquid crystal panel unit 1, a backlight module unit 2, a luminance change detection unit 3, a frame buffer 4, a feature amount detection unit 5, an update mode determination unit 7, a backlight luminance temporary determination unit 101, and a back light. The light luminance determination unit 102 and the backlight luminance storage unit 103 are included. The image display device of FIG. 7 further includes a luminance estimation unit 9, a correction coefficient calculation unit 10, a correction coefficient multiplication unit 11, and a Limit unit 12.

  Liquid crystal panel unit 1, backlight module unit 2, luminance change detection unit 3, frame buffer 4, feature amount detection unit 5, update mode determination unit 7, luminance estimation unit 9, correction coefficient calculation unit 10, correction coefficient multiplication unit 11, The Limit unit 12 is the same as that of the first embodiment, and thus the description thereof is omitted.

  The backlight brightness temporary determination unit 101 temporarily determines the backlight brightness for each light source from the feature amount detected by the feature amount detection unit 5. In the present embodiment, similarly to the first embodiment, the backlight brightness of the light source corresponding to each block is temporarily determined from the maximum pixel value of each block. The determination method is the same as that of the backlight luminance determination unit 8 of the first embodiment, and thus the description thereof is omitted.

  The backlight brightness determination unit 102 determines the backlight brightness based on the backlight brightness temporarily determined by the backlight brightness temporary determination unit 101 and the backlight brightness stored by the backlight brightness storage unit 103. Specifically, the backlight luminance determination unit 102 determines backlight luminance for each light source based on the determination result of the update mode of the update mode determination unit 7.

  In the case of the update mode 0, the backlight luminance determination unit 102 determines, for all light sources, the backlight luminance temporarily determined by the backlight luminance temporary determination unit 101 as the backlight luminance to be applied to the display of the current frame. Also, the backlight brightness determination unit 102 replaces (updates) the backlight brightness of all the light sources stored in the backlight brightness storage unit 103 with the backlight brightness temporarily determined by the backlight brightness temporary determination unit 101. .

  In the case of the update mode 1, it can be determined that the scene has been moved by the cursor. The backlight brightness determination unit 102 compares the brightness temporarily determined by the backlight brightness temporary determination unit 101 with the past brightness stored in the backlight brightness storage unit 103, and selects the one with the lower brightness. It is determined as the backlight luminance applied to the display of the frame of. In addition, the backlight luminance determination unit 102 selects the backlight luminance of the light source for which the luminance temporarily determined by the backlight luminance temporary determination unit 101 is selected as the backlight luminance to be applied to the display of the current frame. Update with brightness.

It demonstrates using FIG. 8 (a) and FIG.8 (b). FIG. 8A shows an example of the backlight luminance temporarily determined by the backlight luminance temporary determination unit 101, and FIG. 8B shows an example of the backlight luminance stored by the backlight luminance storage unit 103. The numerical values in each block in FIG. 8A and FIG. 8B indicate backlight luminance. In addition, the numbers outside 1 to 8 and 1 to 6 outside the grid are horizontal /
Indicates vertical coordinates.

  The luminance of the light source at the coordinates (3, 2) is 0 in FIG. 8 (a) and 100 in FIG. 8 (b). Therefore, the backlight luminance determination unit 102 applies the lower luminance, that is, the backlight luminance temporarily determined by the backlight luminance temporary determination unit 101 shown in FIG. 8A to the display of the current frame. Choose as. Furthermore, an instruction to update the luminance of the light source of the stored coordinates (3, 2) with the temporarily determined backlight luminance is sent to the backlight luminance storage unit 103.

  The luminance of the light source at coordinates (5, 2) and (6, 2) is 100 in FIG. 8A and 0 in FIG. 8B. Therefore, the backlight luminance determination unit 102 applies the lower luminance, that is, the backlight luminance stored in the backlight luminance storage unit 103 shown in FIG. 8B to the display of the current frame. select.

  The light sources of the other blocks are applied to the display of the current frame because there is no change between the backlight brightness temporarily determined by the backlight brightness temporary determination unit 101 and the backlight brightness stored by the backlight brightness storage unit 103. Either value may be used as backlight brightness. In this embodiment, in such a case, the value determined by the backlight luminance temporary determination unit 101 is used as backlight luminance to be applied to display of the current frame.

  The backlight luminance applied to the display of the current frame determined in this manner is as shown in FIG. 6 as in the first embodiment.

  In the case of the update mode 2, since there is no change in the image, the backlight luminance temporarily stored in the backlight luminance temporary determination unit 101 and stored in the backlight luminance storage unit 103 are used as the backlight luminance applied to the display of the current frame. It is possible to use either of the above backlight luminances. In the present embodiment, the luminance stored in the backlight luminance storage unit 103 is used.

  The backlight luminance determination unit 102 outputs the information on the backlight luminance to be applied to the display of the current frame determined in this manner to the luminance estimation unit 9 and the backlight module unit 2 in the subsequent stage.

  The above is the details of the second embodiment. With the above configuration, as in the first embodiment, even when the object image (cursor) of high luminance moves in the dark area of the image, both the block of the movement source and the block of the movement destination have high luminance pixel values of the cursor You will no longer be brightly lit. That is, since each light source can be made to emit light with backlight luminance that will be realized if the cursor does not exist in the original image, both contrast improvement by local dimming and suppression of halo effect and flicker are achieved. be able to.

(Example 3)
In the first and second embodiments, the number of pixels whose luminance has changed in the previous and subsequent frames is counted, and the count value is compared with a threshold to detect a scene in which the cursor has moved. In the third embodiment, the scene to which the cursor has moved is detected by directly detecting the cursor as an object. Then, from the feature amount of the current frame and the feature amount of the past frame stored, the feature amount in the case where the cursor does not exist in the current frame is obtained, and the back applied to the display of the current frame based on the feature amount Determine the light intensity. As a result, as in the first and second embodiments, in the image display apparatus for improving the contrast by local dimming according to the input image, both the halo effect and the flicker when the cursor of high brightness moves in the dark area of the image It can be suppressed. Further, as compared with the first and second embodiments, since the cursor is directly recognized, the erroneous determination of the scene of the movement of the cursor is reduced.

FIG. 9 shows a functional block diagram of the image display apparatus in the third embodiment. The image display device of FIG. 9 includes a liquid crystal panel unit 1, a backlight module unit 2, a cursor detection unit 201, a pattern storage unit 202, a cursor movement detection unit 203, an update mode determination unit 204, a scene determination unit 205, and a feature storage unit. 206, a feature amount detection unit 5 is provided. The image display device of FIG. 9 further includes a backlight luminance determination unit 207, a luminance estimation unit 9, a correction coefficient calculation unit 10, a correction coefficient multiplication unit 11, and a Limit unit 12.
The liquid crystal panel unit 1, the backlight module unit 2, the feature amount detection unit 5, the luminance estimation unit 9, the correction coefficient calculation unit 10, the correction coefficient multiplication unit 11, and the Limit unit 12 are the same as in the first embodiment, and thus the description is omitted.

  The cursor detection unit 201 detects a cursor from image data. The detection method stores a shape that can be taken as a cursor, and checks to detect whether there is an object having a shape that matches the pattern stored in the image data. The information on the pattern of the cursor shape is stored in the pattern storage unit 202, and the cursor detection unit 201 reads out the information on the pattern from the pattern storage unit 202 at a necessary timing. When the cursor is detected, the cursor detection unit 201 also obtains the center pixel of the detected cursor and the coordinates of the block to which the cursor belongs. The cursor detection unit 201 outputs, to the cursor movement detection unit 203, information on the position of the central pixel of the cursor among the results thus obtained. The cursor detection unit 201 outputs information of the coordinates of the block to which the cursor belongs to the feature amount storage unit 206.

  The cursor movement detection unit 203 stores information on the position of the central pixel of the cursor detected by the cursor detection unit 201, and detects that the position of the central pixel of the cursor has changed. Specifically, the cursor movement detection unit 203 compares the position of the central pixel of the stored cursor with the position of the central pixel of the cursor newly received from the cursor detection unit 201, and checks whether there is a change.

When there is a change in the position of the central pixel of the cursor, the cursor movement detection unit 203 notifies the update mode determination unit 204 of the value “1” indicating that the cursor has moved.
If there is no change in the position of the central pixel of the cursor, but the cursor is detected, the cursor movement detection unit 203 instructs the update mode determination unit 204 that the cursor is present but the cursor is not moved. 2 ”is notified.
When the cursor is not detected, the cursor movement detection unit 203 notifies the update mode determination unit 204 of the value “0” indicating that the cursor is not present.

  The update mode determination unit 204 notifies the feature amount storage unit 206 and the backlight luminance determination unit 207 of information on the update mode. When the cursor movement detection unit 203 is notified of the value “1” indicating that the cursor has been moved, the update mode determination unit 204 sets the update mode 1. The update mode determination unit 204 sets the update mode 2 when the cursor is detected but the value “2” indicating that the movement of the cursor is not detected is notified. When notified of the value “0” indicating that the cursor is not detected, the update mode determination unit 204 sets the update mode 0.

The scene determination unit 205 performs still image / moving image determination based on changes in preceding and succeeding frames of the feature amount. Even in the case of a still image, when the image changes, it is determined to be a moving image. The scene determination unit 205 reads out the feature amount detected by the feature amount detection unit 5 and the feature amount stored by the feature amount storage unit 206, and counts blocks in which the feature amount has changed. In the present embodiment, the scene determination unit 205 counts blocks in which the maximum value of the feature value has changed. In the present embodiment, the scene change is determined based on the maximum value of the feature amount, but the average value of the feature amounts may be used to determine the scene change. Alternatively, the scene change may be determined based on both the maximum value of the feature amount and the average value of the feature amount. If the number of blocks in which the maximum value of the feature value has changed is equal to or greater than a preset threshold, the scene determination unit 205 determines that the input image is a moving image and indicates a value “1” indicating that the image is a moving image. It is output to the feature amount storage unit 206. Otherwise, the scene determination unit 205 outputs the value “0” indicating that the input image is a still image to the feature storage unit 206.

  The feature storage unit 206 stores the feature detected by the feature detection unit 5. In response to the results of the update mode determination unit 204 and the scene determination unit 205, the feature amount storage unit 206 selects a block whose data is to be updated. The relationship between the update mode of the update mode determination unit 204, the determination result of the scene determination unit, and the method of selecting a block to be updated is shown in FIG. If the scene determination is “1”, that is, in the case of a moving image, the feature amount storage unit 206 detects the feature amounts of all the stored blocks regardless of the result of the update mode of the update mode determination unit 204 The feature amount of the current frame detected by the unit 5 is updated. On the other hand, when the determination result of the scene determination unit 205 is 0, the processing differs depending on the update mode.

  In update mode 0, the cursor does not exist. Therefore, the feature amount storage unit 206 updates the feature amounts of all the blocks with the feature amounts of the current frame detected by the feature amount detection unit 5.

  In the case of update mode 1, it is a scene to which the cursor has moved. If the image is a still image and the movement of the cursor is involved, the movement of the cursor may cause a halo effect or flicker. Therefore, in order to suppress an increase in backlight luminance in the block to which the cursor is moved, the feature storage unit 206 does not update the block to which the cursor is moved with the feature detected by the feature detector 5. The feature amount storage unit 206 receives the coordinates of the block to which the cursor is moved from the cursor detection unit 201. On the other hand, the feature storage unit 206 updates the block at the movement source of the cursor and the other blocks with the feature detected by the feature detection unit 5.

  In the case of the update mode 2, since the image is a still image and there is no movement of the cursor, the feature storage unit 206 does not update the feature for all blocks.

  The backlight luminance determination unit 207 determines the backlight luminance of the light source corresponding to each block according to the feature amount stored by the feature amount storage unit 206. The determination method is the same as that of the first embodiment, so the description is omitted.

  The above is the details of the third embodiment. By the above configuration, as in the first and second embodiments, even when the object image (cursor) with high brightness moves in the dark area of the image, it is possible to achieve both improvement in contrast and suppression of the halo effect and flicker. Can. Further, as compared with the first and second embodiments, since the cursor is directly recognized, the erroneous determination of the scene of the movement of the cursor is reduced.

(Example 4)
In the embodiments so far, the movement of the mouse cursor is detected, and the backlight luminance is controlled based on the past statistics value and the past backlight luminance to change the luminance of the backlight due to the movement of the mouse cursor. It was suppressed or not changed. This suppresses the halo and flicker due to the movement of the mouse cursor.

In the fourth embodiment, a scene to which the mouse cursor has moved is detected, and a block to which the mouse cursor has moved is specified. For the block to which the mouse cursor moves, make the speed of change of the backlight luminance (rate of change, amount of change per frame, amount of change per unit time) according to the change of feature amount smaller than that of normal block . The normal block is a block other than the block to which the mouse cursor is moved. As a result, in the block to which the mouse cursor is moved, it is suppressed that the backlight is suddenly brightened by the appearance of the mouse cursor composed of bright pixels. In addition, even when the mouse cursor stops at the block to which the mouse cursor is moved, the luminance of the backlight of the block to which the mouse cursor is moved slowly increases, so that it is possible to suppress recognition as flicker.

  FIG. 12 shows a functional block diagram of the fourth embodiment. The image display device of FIG. 12 includes a liquid crystal panel unit 1, a backlight module unit 2, a feature amount detection unit 301, a feature amount storage unit 206, a scene determination unit 302, a cursor movement block detection unit 303, and a backlight luminance temporary determination unit 304. , And a smoothing processing unit 305. The image display device of FIG. 12 further includes a backlight luminance storage unit 306, a luminance estimation unit 9, a correction coefficient calculation unit 10, a correction coefficient multiplication unit 11, and a Limit unit 12.

  The feature amount detection unit 301 detects the maximum value and the average value of the pixel values for each block corresponding to each light source of the backlight as in the first embodiment, and the number of bright pixels for each block (referred to as the number of bright pixels) Are counted and acquired as feature quantities. Here, a bright pixel is a pixel whose pixel value (tone value) is equal to or greater than a predetermined threshold. As the threshold value, for example, a typical value can be set as a pixel value of a pixel forming an image of a mouse cursor.

  The scene determination unit 302 determines a scene in which the mouse cursor has moved. For example, the scene determination unit 302 determines that the number of blocks in which the maximum value of pixel values in blocks has increased between frames is equal to or less than the threshold and the number of blocks in which the maximum value of pixel values in blocks is decreased between frames is equal to or less than the threshold. In this case, it is determined that the scene in which the cursor has moved. Alternatively, the scene determination unit 302 may determine that the scene is a scene in which the cursor has moved, when the sum of all the absolute values of the differences between frames of the average value of pixel values in each block is less than or equal to a threshold. . Alternatively, the scene determination unit 302 may determine that the scene has been moved by the cursor when both of the above conditions are satisfied. Alternatively, the scene determination unit 302 may detect the movement of the cursor using the method described in the first to third embodiments, and may detect the scene in which the cursor has moved using the detection result. The scene determination unit 302 outputs the scene determination result to the cursor movement block detection unit 303.

  When the scene determination unit 302 detects a scene to which the cursor has moved, the cursor movement block detection unit 303 detects a block to which the cursor has moved. The cursor movement block detection unit 303 acquires the number of bright pixels of the target block to determine whether or not the cursor is the movement destination. Then, when the number of bright pixels of the target block is 1 or more and the threshold or less, and the difference between the average value of the pixel values of the target block and the average value of the pixel values of surrounding blocks is the threshold or less The movement block detection unit 303 determines that the target block is the movement destination of the cursor. The cursor movement block detection unit 303 outputs, to the smoothing processing unit 305, information of the block detected as the block to which the cursor is moved.

  The backlight brightness temporary determination unit 304 temporarily determines the backlight brightness for each light source based on the feature amount detected by the feature amount detection unit 301 as in the first to third embodiments. The backlight brightness temporary determination unit 304 sends the temporarily determined backlight brightness for each light source to the smoothing processing unit 305.

The smoothing processing unit 305 performs the back light for each light source based on the backlight luminance determined by the backlight luminance temporary determination unit 304 and the backlight luminance one frame before stored in the backlight luminance storage unit 306. Determine the light intensity. That is, the smoothing processing unit 305 controls the change amount of the light emission luminance of the light source according to the change amount of the brightness of the image from the past frame to the target frame for which the light emission luminance is determined. The ratio of the change amount of the light emission luminance to the change amount of is expressed by a predetermined coefficient. When the backlight luminance temporarily determined by the backlight luminance temporary determination unit 304 is higher than the backlight luminance applied to the display of the previous frame, the smoothing processing unit 305 calculates the difference and calculates the difference as the difference. The value multiplied by the coefficient is added to the backlight intensity of the previous frame. This coefficient represents the ratio of the change amount of the light emission luminance of the light source to the change amount of the brightness of the image of the current frame and the previous frame.
For example, assuming that the backlight brightness of the previous frame is L (-1) and the temporarily determined backlight brightness of the current frame is preL (0), the difference ΔL is as follows.

ΔL = preL (0) −L (-1)

The smoothing processing unit 305 obtains the backlight luminance L (0) of the current frame for the block not detected as the cursor movement destination block by the cursor movement block detection unit 303 as follows.

L (0) = L (-1) + ΔL × α / 100

Here, the coefficient is α (%). On the other hand, the smoothing processing unit 305 sets the coefficient to β (%) for the block detected as the cursor movement destination block by the cursor movement block detection unit 303. Here, α >> β. The smoothing processing unit 305 obtains the backlight luminance of the cursor movement destination block as follows.

L (0) = L (-1) + ΔL × β / 100

That is, the backlight luminance of the current frame is determined based on the coefficient α in a normal block that is not the cursor movement destination block, but the backlight luminance of the current frame is determined based on the coefficient β in the cursor movement destination block. In the cursor movement destination block, the feature amount indicating the brightness in the block is increased due to the movement of the cursor, and the backlight luminance temporarily determined based on the feature amount is also increased, but α >> β. The increase in backlight brightness that is ultimately determined is suppressed. Therefore, an increase in backlight luminance due to the cursor is suppressed, so that flicker and halo can be suppressed.
Note that β may have a value equal to or less than 1/100 of α in order to sufficiently suppress the change in backlight luminance in the cursor movement destination block.

Reference Signs List 1 liquid crystal panel unit, 2 backlight module unit, 3 luminance change detection unit, 5 feature amount detection unit, 7 update mode determination unit, 8 backlight luminance determination unit

The present invention relates Viewing apparatus and a control method thereof.

The present invention has an individual light source more capable of changing the light emission luminance in Viewing apparatus for controlling the emission luminance of each light source in accordance with the image of the region corresponding to each light source, the object image such as a cursor The purpose is to suppress the halo effect and flicker caused by movement.

The present invention includes a plurality of light sources can be controlled individually emission luminance,
A display panel that displays an image on a screen by modulating light from the plurality of light sources ;
Control means for controlling the emission brightness of each of the plurality of light sources according to the brightness of the block of the screen corresponding to each of the plurality of light sources ;
When a high brightness object of a predetermined area or less used for assisting the user operation is moved between frames, the control means controls the emission brightness of the light source corresponding to the block in which the high brightness object is present. speed of change, so as to be smaller than the rate of change of light emission luminance of light sources corresponding to the other blocks, a table shown apparatus characterized by controlling the emission luminance of each of the plurality of light sources.

The present invention is a control method for individually and a plurality of light sources capable of controlling the light emission luminance, a display panel for displaying an image on a screen by modulating the light before Symbol plurality of light sources, et al., Display Ru provided with a device And
According to the brightness of the block of the screen corresponding to, respectively Re said plurality of light Minamotoso includes a control step of controlling the emission luminance of each of the plurality of light sources,
When a high brightness object having a predetermined area or less used for assisting the user operation is moved between frames, the control step may change the speed of change of the light emission brightness of the light source corresponding to the block in which the high brightness object is present. but to be smaller than the rate of change of light emission luminance of light sources corresponding to the other block is a control method for Viewing apparatus characterized by controlling the emission luminance of each of the plurality of light sources.

According to the present invention, in the Viewing apparatus for controlling the emission luminance of each light source in response to the individual light emission luminance has a plurality of light sources that can be changed, the image of the region corresponding to each light source, an object such as a cursor It is possible to suppress the halo effect and the flicker caused by the movement of the image.

Claims (20)

Light emitting means having a plurality of light sources capable of individually controlling light emission luminance;
Display means for displaying an image on a screen by modulating light from the light emitting means;
Control means for controlling the light emission luminance of each light source according to the image of the area on the screen corresponding to each of the plurality of light sources;
Equipped with
When the difference between the image of the target frame for which the light emission luminance is to be determined and the image of the frame earlier than the target frame is due to the movement of a predetermined object, the control means is an image brighter than the previous frame in the target frame What is claimed is: 1. An image display apparatus characterized by suppressing a change in light emission luminance of a light source corresponding to the region from light emission luminance of a light source corresponding to the region in a past frame.   When the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object, the control means corresponds to the area of the image in which the brightness has not changed from the past frame in the target frame The image display apparatus according to claim 1, wherein a change in the light emission luminance of the light source to the light emission luminance of the light source corresponding to the region of the past frame is suppressed.   When the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object, the control means determines the emission brightness of the light source corresponding to the area of the image darker than the past frame in the target frame. The image display apparatus according to claim 1, wherein the light emission luminance corresponds to the brightness of the image of the area of the target frame. It further comprises storage means for storing information on the brightness of the image of the area corresponding to each light source used by the control means to determine the light emission luminance of each light source,
When the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object, the control means stores the brightness of the image of each region of the target frame and the storage means The brightness of the image of each region of the past frame is compared, and as a result of the comparison, the light emission luminance of the light source corresponding to the region of the image brighter than the past frame in the target frame is stored in the storage unit The image display device according to any one of claims 1 to 3, which is determined according to the brightness of the image of the area in question.   The control means, as a result of comparison, shows the emission luminance of the light source corresponding to the area where the brightness of the image has not changed from the past frame in the target frame, in the area of the past frame stored in the storage means. The image display device according to claim 4, wherein the image display device determines the brightness according to the brightness of the image.   The control means determines the light emission luminance of the light source corresponding to the area of the image darker than the past frame in the target frame as a result of comparison according to the brightness of the image of the area in the target frame. Image display device as described. It further comprises storage means for storing information on the light emission luminance of each light source,
When the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object, the control means corresponds to each of the regions obtained according to the brightness of the image of each region of the target frame The light emission luminance of the light source is compared with the light emission luminance of each light source applied to the display of the image of the past frame stored in the storage means, and the light source luminance higher than the past frame in the target frame The image display apparatus according to any one of claims 1 to 3, wherein the light emission luminance of the past frame stored in the storage means is applied. 8. The control method according to claim 7, wherein the light emission luminance of the past frame stored in the storage means is applied to the light source whose light emission luminance has not changed from the past frame in the target frame as a result of comparison. Image display device.   The control means applies the light emission luminance obtained according to the brightness of the image of each region of the target frame to the light source whose light emission luminance is lower than the past frame in the target frame as a result of comparison. Image display device as described.   When the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object, the control means determines the emission brightness of the light source corresponding to the area of the image brighter than the past frame in the target frame. The image display apparatus according to any one of claims 1 to 9, wherein the light emission luminance corresponds to the brightness obtained by averaging the brightness of the image of the region in the past frame and the brightness of the image of the region in the target frame. .   The control means is configured such that when the number of pixels having different luminances between the image of the target frame and the image of the past frame is equal to or less than a threshold, the difference between the image of the target frame and the image of the past frame is due to movement of a predetermined object The image display apparatus of any one of Claims 1-10 determined to be.   The control means is configured such that an object having a shape matching the shape that the predetermined object can take exists in the image of the target frame and the image of the past frame, and the position of the object is the image of the target frame and the past frame The image processing method according to claim 1, wherein it is determined that the difference between the image of the target frame and the image of the past frame is due to the movement of a predetermined object when the input image is a still image, unlike the image of The image display device according to any one of the items.   The controller according to any one of claims 1 to 12, wherein, when the input image is a moving image, the control means sets the emission brightness of the light source corresponding to each area to the emission brightness according to the brightness of the image of each area of the target frame. The image display device according to item 1.   When the predetermined object does not exist in the image of the target frame, the control means sets the emission luminance of the light source corresponding to each region as the emission luminance according to the brightness of the image of each region of the target frame. The image display apparatus of any one of -13.   The control means suppresses the change from the light emission luminance of the light source corresponding to each area of the past frame of the light emission luminance of the light source corresponding to each area when there is no change between the image of the target frame and the image of the past frame The image display apparatus of any one of Claims 1-14.   The control means is configured such that an object having a shape matching the shape that the predetermined object can take exists in the image of the target frame and the image of the past frame, and the position of the object is the image of the target frame and the past frame When the input image is a still image, the change of the emission brightness of the light source corresponding to each area from the emission brightness of the light source corresponding to each area of the past frame is suppressed The image display apparatus of any one of Claims 1-15.   The control means determines whether or not the object is a scene in which the object moves with respect to a target frame, and when it is determined that the object is a scene in which the object moves, detects a region to which the object moves in the target frame. The light emission luminance is controlled such that the change amount of the light emission luminance per unit time is smaller for the light source corresponding to the area to which the object moves, than the light source corresponding to the other area. Image display device. The control means controls the amount of change in light emission luminance of the corresponding light source according to the amount of change in brightness of the region of the image from the past frame to the target frame, and the movement destination of the object in the target frame The image display device according to claim 17, wherein the ratio of the change amount of the light emission luminance to the change amount of the brightness of the image is smaller than the light source corresponding to the other regions for the light source corresponding to the region of.   The control means is configured to calculate a value obtained by multiplying a difference between a light emission luminance obtained according to the brightness of the image of the target frame and a light emission luminance applied to the display of the image of the past frame by a coefficient. The light emission luminance to be applied to the display of the image of the object frame is determined by adding to the light emission luminance applied to the display of the image, and the light emission luminance of the light source corresponding to the region to which the object is moved is determined. The image display device according to claim 17 or 18, wherein the coefficient β used for the pixel and the coefficient α used for determining the light emission luminance of the light source corresponding to the other region satisfy the relationship β << α. Light emitting means having a plurality of light sources capable of individually controlling light emission luminance;
Display means for displaying an image on a screen by modulating light from the light emitting means;
A control method of an image display apparatus comprising:
According to the image of the area on the screen corresponding to each of the plurality of light sources, there is a control step of controlling the light emission luminance of each light source,
In the control step, when the difference between the image of the target frame for which the light emission luminance is to be determined and the image of the previous frame from the target frame is due to the movement of a predetermined object, the image brighter than the past frame in the target frame A control method of an image display apparatus characterized by suppressing a change from light emission luminance of a light source corresponding to the area of a past frame of light emission luminance of a light source corresponding to the area of.

Images