JP2012002936A - Display control device, display apparatus, and display control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology able to suitably determine a quantity of back light used for illuminating a display, without increasing the scale of an ASIC.SOLUTION: The display control device divides an input image into a plurality of areas, and derives a quantity of back light based on pixel data extracted from part of the areas. Accordingly, without greatly reducing accuracy in the determination of a quantity of backlight, the capacity of a memory used for a determination-reference generating process and so on can be reduced, an increase in the size of a display control device can be avoided, and hence costs can be reduced.

Description

  The present invention relates to a technique for controlling a light amount of a backlight that illuminates a display screen.

  There is a technique in which unnecessary power is not consumed in the backlight by deriving the amount of light of the backlight that illuminates the liquid crystal screen based on pixel data constituting an image displayed on the liquid crystal screen.

  For example, Patent Document 1 discloses a technique for deriving the amount of backlight light from a histogram generated based on all pixel data of a plurality of pixel data constituting an image input to a circuit such as an ASIC mounted on the apparatus. Are listed.

JP 2009-251331 A

  However, in a circuit such as an ASIC, in order to derive the light amount of the backlight that illuminates the liquid crystal screen based on the input image, the capacity of the memory mounted in the circuit must be made appropriate. That is, in order to execute a process for generating a histogram or the like in a circuit, a memory having a capacity corresponding to all the pixel data constituting the image is required, so that the circuit scale increases as the memory capacity increases. There is.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of appropriately deriving the amount of light of a backlight that illuminates a liquid crystal screen without increasing the scale of a circuit.

  In order to solve the above-mentioned problem, the invention of claim 1 is a display control device that displays an image on a screen illuminated by a backlight, and divides an input image into a plurality of regions, and a part of the regions Data extraction means for extracting the pixel data, light quantity derivation means for deriving the light quantity of the backlight based on the extracted data, and backlight control means for controlling the backlight so as to obtain the derived light quantity And.

  Further, the invention according to claim 2 is the display control device according to claim 1, wherein the data extraction means divides the input image into a plurality of areas, extracts a part of the maximum pixel data in the area, The light amount deriving unit generates a histogram from the extracted plurality of maximum pixel data, and derives the light amount of the backlight from the histogram based on predetermined highest pixel data.

  According to a third aspect of the present invention, in the display control device according to the first or second aspect, an image to be displayed on the screen in accordance with a degree of reduction of the derived light amount from a reference light amount. And a display control means for displaying the amplified image on the screen, the data extraction means divides the input image into a plurality of areas, A part of the maximum pixel data is extracted.

  According to a fourth aspect of the present invention, in the display control apparatus according to any one of the first to third aspects, the data extracting means divides a part of the inputted image into the plurality of regions. It is characterized by that.

  According to a fifth aspect of the present invention, in the display control device according to any one of the first to fourth aspects, the data extraction means determines the size of the plurality of regions divided in the input image by an image. The image center vicinity is made smaller than the edge vicinity.

  The invention of claim 6 is characterized by comprising the display control device according to any one of claims 1 to 5, the backlight, and the screen.

  According to a seventh aspect of the present invention, there is provided a display control method for displaying an image on a screen illuminated by a backlight, wherein the input image is divided into a plurality of regions, and the pixels are based on a part of the pixels in the region. A step of extracting data; a step of deriving a light amount of the backlight based on the extracted data; and a backlight step of controlling the backlight so as to obtain the derived light amount. Features.

  According to the first to seventh aspects of the present invention, the input image is divided into a plurality of regions, and the light amount of the backlight is derived based on the pixel data extracted from a part of the region. Without greatly reducing the accuracy, the capacity of the memory used for the light quantity derivation process can be reduced, the display control device can be prevented from being enlarged, and the cost can be reduced.

  According to the second aspect of the present invention, the input image is divided into a plurality of regions, a part of the maximum pixel data in the region is extracted, and a predetermined histogram is generated from a histogram generated from the extracted plurality of maximum pixel data. Since the backlight light amount is derived based on the second highest pixel data, it is not necessary to generate a histogram based on all the pixel data constituting the image to derive the backlight light amount. As a result, it is possible to reduce the capacity of the memory used for the histogram generation processing and the like without greatly reducing the light amount derivation accuracy of the backlight, to prevent the display control apparatus from becoming large and to reduce the cost.

  According to the invention of claim 3, since the pixel data used when generating the histogram uses the maximum pixel data in each region, the image is amplified according to the degree of reduction of the derived light amount from the reference light amount. In this case, it is possible to prevent the brightness of some pixels in the image from being saturated.

  According to the invention of claim 4, the backlight control is performed with emphasis on the brightness of a part of the input image, for example, a part where important information is displayed in the image. It is possible to increase the image processing speed while ensuring good.

  According to the fifth aspect of the present invention, it is possible to improve the visibility of the central portion of the image by accurately analyzing the brightness of the central portion where the important information tends to be displayed in the image.

FIG. 1 is a diagram illustrating a display unit. FIG. 2 shows an image. FIG. 3 is a system configuration diagram of the in-vehicle device. FIG. 4 is a flowchart showing the contents of control executed by the in-vehicle device. FIG. 5 is a diagram illustrating pixels in an image. FIG. 6 is a diagram illustrating a histogram of pixel data. FIG. 7 shows an image. FIG. 8 shows an image. FIG. 9 is a diagram illustrating pixels in an image.

  The display control technology described below is applied to various display devices equipped with a display unit. For convenience, the in-vehicle device that is one of the various display devices will be specifically described. To do. Hereinafter, the in-vehicle device will be described separately with reference to the accompanying drawings by dividing the structure of the display unit mounted in the in-vehicle device, the configuration of the in-vehicle device, and the control of the in-vehicle device.

<Representative embodiment>
<Configuration of display unit mounted on in-vehicle device>
The structure of the display part with which the vehicle-mounted apparatus which is a display apparatus mounted in a vehicle is provided is demonstrated based on FIG. The display unit 7 includes a color filter 1, a liquid crystal layer 2, a TFT (Thin Film Transistor) 3, a backlight 5, and a touch panel 4.

  The color filter 1 is a film on which three primary colors (RGB) are printed for each pixel.

  The liquid crystal layer 2 is a so-called liquid crystal shutter whose molecular arrangement changes when an external voltage or the like is applied.

  The TFT 3 is a thin film transistor composed of electrodes arranged in a matrix. The TFT 3 changes the molecular arrangement of the liquid crystal in the liquid crystal layer 2 corresponding to the cell by generating a voltage to the target cell in a matrix form by controlling the electricity that the TFT control unit flows to the electrode, that is, the backlight. The light is transmitted to the color filter 1 side and the target color is displayed on the liquid crystal screen.

  The backlight 5 has a plurality of LEDs (Light Emitting Diodes) 5 serving as light sources arranged in series. That is, the backlight 5 has a function of illuminating the liquid crystal screen of the display unit constituted by the color filter 1, the liquid crystal layer 2, and the TFT 3.

  The type of the backlight 5 is an edge light type with a simple structure, and it can be said that it is an optimum structure for an in-vehicle device that requires a thin display portion, that is, a small size. In such an edge light type backlight, the LEDs 5 as a plurality of light sources are provided in series in the vicinity of the bottom side (lower base) of the display unit having a rectangular shape, so that the light faces the one side in the display unit 7. A polarizing plate is provided to prevent the light from becoming weaker toward the bottom (upper base), that is, to make the light of the backlight uniform in the display unit 7.

  Moreover, the backlight 5 can change the light quantity of LED5 by changing not only the simple light emission which makes LED5 which comprises comprise light but not light emission, and the duty ratio of the control current which controls LED5 differ.

  The touch panel 4 is a panel composed of transparent electrodes made of a metal thin film having resistance. The touch panel 4 has the electrodes arranged in a matrix, and a voltage is generated in the vicinity of the electrodes corresponding to the position of the liquid crystal screen touched by the user. For this reason, the in-vehicle device can determine that the position where the voltage is generated is the position operated by the user.

  Of the display unit 7 in which the color filter 1, the liquid crystal layer 2, the TFT 3, the backlight 5, the touch panel 4, and the like are stacked, the TFT 3 and the backlight 5 are used as the TFT control unit and the backlight control of the in-vehicle device. By controlling the unit, as shown in FIG. 2, an image such as a car navigation image or a TV image can be displayed on the liquid crystal screen of the display unit 7.

<Configuration of in-vehicle device>
Next, the configuration of the in-vehicle device will be described with reference to FIG. The in-vehicle device 27 includes a display unit 7, a volatile storage unit 11, a display control unit 16, an input switching unit 17, a control unit 18, a broadcast receiving unit 19, a camera input unit 20, a disk reading unit 21, and a car navigation unit 22. Are electrically connected to a bus or signal line capable of data communication.

  The control unit 18 is a microcomputer configured by a ROM or the like in which a CPU, a control program, and the like are stored. For example, the control unit 18 receives a user operation from the touch panel 4 and outputs an image corresponding to the user operation to the display control unit 16, so that the broadcast receiving unit 19, the camera input unit 20, the disk reading unit 21, or The input switching unit 17 is switched so that an image output from any of the car navigation units 22 is displayed on the display unit 7.

  The input switching unit 17 receives a switching instruction from the control unit and outputs a broadcast reception unit 19, a camera input unit 20, a disk reading unit 21, or a card so that an image corresponding to the instruction is output to the display control unit 16. This is a hardware circuit that switches the route of an image output from the navigation unit 22 to the display control unit 16.

  The display control unit 16 is an ASIC (Application Specific Integrated Circuit) configured by a logic circuit. For example, the image adjustment unit 8, the TFT control unit 9, the sampling unit 10, the histogram generation unit 12, the analysis unit 13, the light amount derivation unit 14, and the backlight control unit 15 included in the display control unit 16 each have an image adjustment function, The TFT control function, sampling function, histogram generation function, analysis function, light quantity derivation function, and backlight adjustment function are exhibited. Details of these functions will be described later.

  The volatile storage unit 11 is, for example, an SRAM (Static Random Access Memory). The volatile storage unit 11 temporarily stores results such as derived control values when the display control unit 16 performs the respective functions, that is, it functions as a working area.

  The in-vehicle device 27 analyzes a plurality of pixel data constituting an image input to the display control unit 16 that is an ASIC to derive a light amount, but is a memory mounted on the ASIC when performing normal analysis. All pixel data must be stored in the volatile storage unit 11. For this reason, it is necessary to mount a memory having a capacity corresponding to the number of pixels in the ASIC, and there is a problem that the size of the ASIC increases as the number of pixels of the input image increases. Therefore, in the in-vehicle device 27 that is limited in size when mounted on the vehicle 28 and is packed with various functions, a technique described later is employed so that the size of the display control unit 16 that is an ASIC does not increase.

  In addition, the pixel data means a red (R) value, a green (G) value, and a blue (B) value that each of a plurality of pixels constituting the input image has, and values derived based on these values are also included. means.

  The broadcast receiving unit 19 receives a radio wave by a TV broadcast antenna 23 that directly receives a radio wave of a digital TV broadcast emitted in the air, and extracts a TV image as shown in FIG. 2 based on the received radio wave. Take on. In addition, the broadcast receiving unit 19 transmits the extracted TV image to the display control unit 16 via a signal line.

  The camera input unit 20 is provided with an image received via the signal line from the vehicle-mounted camera 24 provided in the vehicle 28 with the imaging direction facing the outside of the vehicle, that is, provided so that an image outside the vehicle can be imaged. It performs functions such as AGC (Automatic Gain Control) for adjusting to an image. In addition, the camera input unit 20 transmits the adjusted image outside the vehicle to the display control unit 16 via a signal line.

  The disk reading unit 21 has a function of reading a DVD image recorded on the DVD 25 set by the user. Further, the disk reading unit 21 transmits the DVD image recorded on the read DVD 25 to the display control unit 16 through a signal line.

  The car navigation unit 22 reads a map image corresponding to the calculated vehicle position data based on the GPS signal received by the GPS antenna 26, etc., from a storage device to be mounted, and combines it with data such as the vehicle position mark, Responsible for generating car navigation images. In addition, the car navigation unit 22 transmits a car navigation image to the display control unit 16.

  In addition, each of the broadcast receiving unit 19, the camera input unit 20, the disk reading unit 21, and the car navigation unit 22 displays an image size (for example, vertical width 480) displayed on the display unit 7 as an image generated in each unit. (Pixel, width 800 pixels), and then transmitted to the display control unit 16.

<Control of in-vehicle devices>
When the control unit 18 of the in-vehicle device 27 receives a user operation for setting the image mode outside the vehicle via the touch panel 4 of the display unit 7, the control unit 18 controls the input switching unit 17 to display the vehicle outside image adjusted by the camera input unit 20. And output to the display control unit 16.

  When the control unit 18 receives a user operation for DVD playback mode setting via the touch panel 4 of the display unit 7, the control unit 18 controls the input switching unit 17 so that the DVD image read from the DVD 25 by the disk reading unit 21 is controlled. And output to the display control unit 16.

  In addition, when the control unit 18 receives a user operation for setting the car navigation mode via the touch panel 4 of the display unit 7, the control unit 18 controls the input switching unit 17 to generate the vehicle position mark generated by the car navigation unit 22. The display control unit 16 outputs a car navigation image including a selection mark for accepting execution of a predetermined function and a map image.

  Thereafter, after the user selects the TV image, the in-vehicle camera image, the DVD image, or the car navigation image selected by the touch panel 4 to the display control unit 16 via the input switching unit 17, The processing executed in the display control unit 16 will be described in detail based on FIG. Note that the control process shown in FIG. 4 is executed each time an image is input to the display control unit 16 at a predetermined cycle, and ends when the power to the in-vehicle device 27 is turned off by the user.

  In step S1, the sampling unit 10 included in the display control unit 16 samples a predetermined number of predetermined data from the input image.

  Specifically, as shown in FIG. 5, the input image is divided by a region 30 which is a predetermined range, for example, a region 30 composed of 6 pixels in the vertical width (Y axis) and 7 pixels in the horizontal width (X axis). Then, a part of pixel data in the divided area is extracted. For example, it is data that satisfies a predetermined condition among data relating to a plurality of pixels (42 pixels in the above example) constituting each of the plurality of regions 30, and specifically, most of the plurality of pixel data constituting the region 30 High pixel data is sampled (extracted) by comparison processing. In other words, the sampled data, that is, the sampling data can be said to be image data of a smaller amount than the input image data of the same amount as the image data displayed on the display unit 7 by the display control unit 16.

  The sampling unit 10 performs this comparison process for each region 30 for all the pixels included in the region 30 in a predetermined order.

  The predetermined order in which the sampling unit 10 performs the comparison process is to compare for each region 30. For example, among the plurality of regions 30 in the segmented input image, the upper left when the input image is viewed from the front When the comparison processing is executed in order from the region 30 to the right adjacent region 30 in the same row, and the execution of the comparison processing is finished for the rightmost region 30 in the row, the leftmost region in the next row The comparison processing is executed in order from the region 30 to the right adjacent region 30 in the same row, and so on until the execution of the comparison processing is completed in the lower right region 30 when the input image is viewed from the front.

  The comparison performed by the sampling unit 10 in the region 30 is performed by, for example, performing comparison of the first row in the region 30 including seven rows of 6 pixels, and volatile the memory of the highest pixel data. The second row is compared and the highest pixel data is stored in the volatile storage unit 11 so that the highest pixel data in the second row and the highest pixel data in the first row are stored. And the higher pixel data is stored in the volatile storage unit 11. Next, the comparison of the third row is executed to store the highest pixel data in the volatile storage unit 11 and the highest pixel data so far is compared with the highest pixel data of the third row. The same comparison is repeated until the last row, such as storing the pixel data in the volatile storage unit 11, and the highest pixel data in the region 30 is stored in the volatile storage unit 11.

  Each of the plurality of pixels constituting the region 30 has a red (R) value, a green (G) value, and a blue (B) value. In such a configuration, pixel data to be compared with other pixel data. Is not the total pixel data of the three data, but the highest pixel data among the three pixel data.

  The sampling unit 10 stores the maximum pixel data in the volatile storage unit 11 having a size having a vertical width (Y axis) 64'd and a horizontal width (X axis) 128'd. That is, the data stored in 11 is smaller than the input image data, and is the minimum necessary data for the histogram generation unit 12 described later to generate a histogram. Next, the process proceeds to step S2.

  In step S2, the histogram generation unit 12 included in the display control unit 16 generates a histogram for the light amount deriving unit 14 to derive the light amount from a plurality of sampled pixel data, that is, from all sampled pixel data. To do.

  Specifically, the histogram generation unit 12 generates a histogram 35 of a plurality of sampled pixel data as shown in FIG. The histogram is data indicating a graph showing a distribution of pixel data of a plurality of pixels constituting an image. Next, the process proceeds to step S3.

  In step S3, the analysis unit 13 included in the display control unit 16 analyzes the generated histogram 35 and extracts pixel data distributed in a predetermined position.

  Specifically, in the generated histogram 35, when the number of pixels is counted from the pixel with the highest pixel data (255) to the pixel with the lowest pixel data (0), the count value is a predetermined value. Pixel data (for example, 220) when exceeding (for example, 200) is extracted. In other words, the predetermined highest pixel data is extracted from the generated histogram 35.

  Here, the reason why the display control unit 16 derives the light amount of the backlight 5 by the histogram 35 based on a plurality of pixel data constituting the image will be described.

  The display control unit 16 generates a histogram 35 of a plurality of pixel data constituting the input image, counts the pixels from the highest pixel data to the lowest pixel data in the generated histogram 35, and the count number is Pixel data of a pixel when a predetermined value is exceeded is extracted. As will be described later, the display control unit 16 derives a light amount based on the extracted pixel data (a reference light amount, for example, a light amount lower than 100%) as a light amount of the backlight 5, and the back light so that the derived light amount is obtained. In addition to controlling the light 5, the pixel data constituting the image is uniformly amplified and displayed on the liquid crystal screen so as to follow the brightness of the image in which the light amount of the backlight 5 becomes darker than the reference light amount. Adjust the overall brightness of the image.

  In other words, when applying this technique, the value of the predetermined value is set in the display control unit 16 so that saturation is unlikely to occur when the pixel data constituting the image is uniformly amplified according to the amount of light. is doing.

  If the display control unit 16 executes the light quantity derivation criterion by the average (data average) of the data of a plurality of pixels constituting the image instead of the histogram, a small number of high pixel data is obtained when the data average is relatively low. There is a risk of saturation when the data of the pixels constituting the above-described image are uniformly amplified.

  Therefore, the display control unit 16 performs the process of deriving the light amount of the backlight based on the histogram and amplifying the data of the pixels constituting the image uniformly as described above, so that the image is not saturated. Visibility is improved. Next, the process proceeds to step S4.

  In step S <b> 4, the light amount deriving unit 14 included in the display control unit 16 derives a light amount based on pixel data obtained by analyzing and extracting the histogram 35.

  The light amount deriving unit 14 has conventionally set a constant light amount regardless of the pixel data, that is, the duty ratio of the control current for controlling the backlight 5 to a fixed value (for example, 100%). In order to reduce the power consumed by the, a predetermined process is executed to derive the duty ratio.

  In other words, the predetermined processing means that the light amount deriving unit 14 extracts pixel data when the above-described count number exceeds a predetermined value (for example, 200th) in the above-described histogram, and the extracted pixel data is the pixel data. The duty ratio is derived by deriving the proportion in the range (for example, 256 from 0 to 255). In the processing, the ratio (for example, 100%) to the maximum value (for example, 256) of the pixel data range can be considered as the reference light amount.

  Accordingly, the light amount deriving unit 14 divides the pixel data obtained by adding 1 to the pixel data when the count number exceeds the predetermined value by the pixel data range 256, and adds 100 to the divided result, thereby obtaining a ratio to the reference light amount. Is derived, and the ratio is used as the duty ratio. In the above example, 220/256 = 86% is the duty ratio of the control current for controlling the backlight 5.

  Specifically, the light quantity deriving unit 14 searches the light quantity associated with the pixel data analyzed and extracted from a non-illustrated non-volatile storage unit in which the light quantity associated with the pixel data is stored. And extract. The light amount deriving unit 14 derives this light amount as the light amount when the backlight control unit 15 controls the backlight 5. Next, the process proceeds to step 5.

  In step S5, the backlight control unit 15 included in the display control unit 16 performs duty control on the LEDs 6 constituting the backlight 5 so that the derived light amount is obtained.

  Specifically, the backlight control unit 15 appears brighter if the duty ratio of the current controlled by the LED 6 is increased, and apparently darker if the duty ratio is decreased. A current for controlling the LED 6 is passed at a high duty ratio.

  Note that the display control unit 16 flickers the image when performing such backlight control for each input image, and therefore the duty ratio according to the difference between the light amount in the previous image and the light amount in the current image. To prevent the image from flickering. Next, the process proceeds to step S6.

  In step S6, the image adjustment unit 8 included in the display control unit 16 reads the pixel data coefficient from the nonvolatile storage unit based on the derived light amount, and multiplies the read pixel data coefficient by the pixel data constituting the input image. To do.

  Specifically, the image adjustment unit 8 searches the pixel data coefficient corresponding to the derived light amount from the nonvolatile storage unit, searches the pixel data coefficient associated therewith, extracts the pixel data coefficient, and inputs it. The pixel data of the image is multiplied by the pixel data coefficient. Next, the process proceeds to step S7.

  In step S <b> 7, the TFT control unit 9 included in the display control unit 16 controls the TFT 3 so that an image multiplied by the pixel data coefficient is displayed on the display unit 7.

  In other words, in the nonvolatile storage unit, the setting for associating the pixel data with the light amount is performed by setting the target brightness of the image when displaying the image on the display unit 7 in the TFT control unit 9 to the brightness based on the pixel data and the light amount. Therefore, the brightness of the image that becomes dark by lowering the light amount of the backlight below the reference light amount is reduced by the brightness of the pixel data so that the power of the backlight 5 is reduced. It is set in a range that can be amplified and followed. Next, the process proceeds to return.

  By adopting the configuration and control as described above, the capacity of the volatile storage unit 11 that is a memory mounted on the ASIC can be reduced, and as a result, a high-definition liquid crystal screen can be illuminated without increasing the size of the ASIC. The amount of light of the backlight can be appropriately derived.

  That is, the derivation of the amount of light when the display control unit 16 controls the backlight 5 generates distribution data (histogram) based on the data of a plurality of pixels in the input image, and the pixels distributed in a predetermined order among the generated distribution data In order to derive the amount of light according to the data, the display control unit 16 that is an ASIC needs to have a corresponding memory capacity to be stored in such processing. That is, as the number of pixels of the input image increases, the capacity of the memory increases and the size of the ASIC increases accordingly. For this reason, the input image is divided into a plurality of areas, the maximum pixel data is extracted from each of the plurality of areas, and a histogram is generated based on the extracted pixel data. Memory capacity can be reduced. As a result, it is possible to prevent an increase in the size of the display control unit 16 that is an ASIC, appropriately derive the amount of light of the backlight that illuminates a high-definition liquid crystal screen, and to be mounted on a small vehicle 28 with a limited mounting area. Can do.

<Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. Below, the modification of the said embodiment is demonstrated. Of course, the modifications described below may be combined as appropriate.

<Modification 1>
In step S1 in the above representative embodiment, “the sampling unit included in the display control unit divides the input image to be displayed on the liquid crystal screen by a region that is a predetermined range, and from each of the plurality of divided regions. Although it has been described that “the highest pixel data is extracted from the plurality of pixel data included”, the sampling unit 10 may divide a part of the input image into a plurality of regions 30.

  Specifically, the sampling unit 10 is a part of the input image and a part where important information is displayed, for example, the own vehicle position mark J in the car navigation image 2G as shown in FIG. A predetermined range B including the route R to the destination is divided by a region 30 that is a predetermined range, and a predetermined number of pixel data is extracted from each of the plurality of divided regions 30.

  As a result, the display control unit 16 performs backlight control with an emphasis on the brightness of the portion of the input image where important information is displayed, so that the visibility of important information is improved and the image processing speed is increased. can do.

<Modification 2>
In step S1 in the above representative embodiment, “the sampling unit included in the display control unit divides the input image to be displayed on the liquid crystal screen by a region that is a predetermined range, and from each of the plurality of divided regions. Although it has been described that “the highest pixel data is extracted from the pixel data of a plurality of pixels included”, the sampling unit 10 may divide a part of the input image into a plurality of regions 30.

  Specifically, the sampling unit 10 selects a TV image 1G and various functions as shown in FIG. 8 as a part of the input image where important information is displayed, for example, the input image. In the case of a composite image 3G including digital information S such as an icon indicating a button, sound volume, and channel information, the range in which the TV image 1G is displayed is divided by a region 30 that is a predetermined range, A predetermined number of pixel data is extracted from each of the regions 30.

  As a result, the display control unit 16 performs backlight control with an emphasis on the brightness of the portion of the input image where important information is displayed, so that the visibility of important information is improved and the image processing speed is increased. can do.

  In addition, the sampling unit 10 sets the size of the plurality of regions 30 divided in the input image to a region 35 including, for example, a vertical width (Y axis) of 6 dots and a horizontal width (X axis) of 7 dots near the end of the input image. The vicinity of the center of the input image may be an area 36 constituted by a vertical width (Y axis) of 3 dots and a horizontal width (X axis) of 3 dots. Alternatively, the region 30 may be set to be gradually smaller from the end of the input image to the center.

  As a result, the display control unit 16 performs backlight control with emphasis on the brightness of the portion of the input image where important information is displayed. By analyzing the brightness with high accuracy, the visibility of the central portion of the image can be improved.

<Modification 3>
In step S2 and step S3 in the representative embodiment, “the histogram generation unit 12 generates a histogram from the sampled pixel data, and the analysis unit 13 analyzes the generated histogram and puts it at a predetermined position. The display control unit 16 includes a data average generation unit instead of the histogram generation unit 12 and the analysis unit 13, and the data average generation unit is a pixel sampled by the sampling unit 10. A data average may be generated, and the light quantity deriving unit may appropriately derive the light quantity based on the data average.

  Rather than generating a data average based on all pixel data in an image and deriving the amount of light from the backlight, the image is divided into a plurality of regions and a predetermined number of pixel data is extracted from each of the plurality of regions. In addition, since the data average based on the multiple pixel data is generated, the memory in the data average generation processing can be reduced without greatly reducing the light amount derivation accuracy of the backlight, the circuit configuration can be reduced, and the cost can be reduced. it can.

<Modification 4>
Although the backlight 5 in the above-described representative embodiment has been described as an LED, any light source capable of illuminating the liquid crystal screen and adjusting the amount of light may be used. For example, a fluorescent lamp may be used.

<Modification 5>
In the above representative embodiment, it has been described that the light amount of the edge light type backlight 5 including a plurality of LEDs in series is derived, and the plurality of LEDs are uniformly controlled based on the derived light amount. May be uniformly controlled.

  Further, a plurality of lines including a plurality of LEDs in series may be provided in parallel, and the controllable backlight 5 may be controlled uniformly for each parallel line.

  Further, in either the backlight 5 having a plurality of LEDs in a matrix or the backlight 5 having a plurality of lines provided in series with a plurality of LEDs in parallel and controllable for each parallel line. The LEDs and the plurality of lines may be individually controlled based on the pixel data extracted from the plurality of regions described above.

<Modification 6>
In the representative embodiment, the predetermined value of the pixel data extracted from each area of the input image by the sampling unit 10 has been described by taking the highest value among the plurality of pixel data as an example. However, the present invention is not limited to this. For example, an average value of a plurality of upper (for example, two) pieces of pixel data among the pixel data of each region may be used as the extracted pixel data of the region. Even in this case, it corresponds to extracting data satisfying a predetermined condition from data regarding a plurality of pixels included in each region.

DESCRIPTION OF SYMBOLS 10 Sampling part 11 Volatile memory | storage part 12 Histogram generation part 13 Analysis part 14 Light quantity derivation | leading-out part 15 Backlight control part 16 Display control part 17 Input switching part 18 Control part 19 Broadcast receiving part 27 In-vehicle apparatus

Claims (7)

A display control device that displays an image on a screen illuminated by a backlight,
A data extraction unit that divides an input image into a plurality of areas and extracts a part of pixel data in the area;
A light amount deriving means for deriving the light amount of the backlight based on the extracted data;
Backlight control means for controlling the backlight so as to obtain the derived light amount;
A display control apparatus comprising: The display control device according to claim 1,
The light amount deriving unit generates a histogram from the plurality of extracted maximum pixel data, and derives the light amount of the backlight from the histogram based on a predetermined highest pixel data. . In the display control device according to claim 1 or 2,
Image amplifying means for amplifying pixel data constituting an image to be displayed on the screen according to the degree of reduction of the derived light amount from a reference light amount;
Display control means for displaying the amplified image on the screen;
Further comprising
A data extraction unit divides an input image into a plurality of regions, and extracts some maximum pixel data in the regions. In the display control device according to any one of claims 1 to 3,
The display control apparatus, wherein the data extraction unit divides the input image into a plurality of regions for a part thereof. The display control device according to any one of claims 1 to 4,
The display control apparatus characterized in that the data extraction means makes the size of the plurality of areas divided in the input image smaller in the vicinity of the center of the image than in the vicinity of the edge of the image. A display control device according to any one of claims 1 to 5;
The backlight;
The screen;
A display device comprising: A display control method for displaying an image on a screen illuminated by a backlight,
Dividing an input image into a plurality of regions and extracting pixel data based on some of the pixels in the region;
Deriving the amount of light of the backlight based on the extracted data;
A backlight process for controlling the backlight so as to obtain the derived light amount;
A display control method comprising:

Images