JP4085285B2 - Flat panel display television receiver and panel signal generator - Google Patents

Description

  The present invention relates to a flat panel display type television receiver capable of correcting signal processing and a panel signal generation apparatus.

  A flat panel display such as an LCD panel or a PDP panel whose display state is controlled by digital gradation tends to lack gradation as compared with an analog CRT. In particular, when a dark screen is expressed on a flat panel display, there is a problem that black crushing occurs due to insufficient gradation. On the other hand, the black crushing is reduced by correcting the luminance characteristics of the video signal output to the flat panel display (see, for example, Patent Document 1).

In such a configuration, the average luminance of the screen data is detected, and the luminance of the dark part and the bright part is expanded according to the average luminance level. That is, in an image with low average luminance, the gradation of the low luminance region is enhanced by extending the low luminance region, and in an image with high average luminance, the gradation of the high luminance region is enhanced by extending the high luminance region.
It is also known to improve the contrast of the display screen by performing gamma correction on the gradations of the high luminance region and the low luminance region according to the average luminance level of the video signal (see, for example, Patent Document 2). ).
JP-A-4-229788 JP-A-11-327496

  In the invention of Patent Document 1 described above, in the case of image data in which the average luminance is low but the difference between the maximum luminance and the minimum luminance is large, the result is that the low luminance portion is expanded. For example, on a screen that is dark overall and bright at only one location, only the gradation of the dark portion is enhanced, and the gradation of the bright portion is not subjected to signal processing.

  In the invention of Patent Document 2, if the average luminance is the same, the same gamma correction is performed. For example, if the average brightness of an entirely dark video scene and a video scene with a bright part in the whole dark is the same, the same gamma correction is applied to both, and the bright part of the latter video scene. Sometimes crushed white.

  The present invention has been made in view of the above problems, and a flat panel display type television receiver capable of clearly displaying a video by performing appropriate signal processing according to the video signal, and a panel An object is to provide a signal generation apparatus.

In order to achieve the above object, according to a second aspect of the present invention, a digital signal obtained by analog / digital conversion based on an analog video signal for analog display of a television is input, and each pixel for a display panel having a predetermined number of pixels is input. A scaler unit that converts to a digital video signal and records image data for one screen in a predetermined frame buffer, and signal processing including image quality adjustment based on image data for each screen recorded in the frame buffer are the same. A first image processing unit in charge of applying image data, and a second image in charge of applying signal processing including γ correction to the image data based on the image data recorded in the frame buffer. The display panel is driven based on the processing unit and the image data recorded in the frame buffer. A control unit that controls a driver unit for generating a drive signal, a scaler unit, a first image processing unit, a second image processing unit, and the driver unit at predetermined time intervals, respectively. With the structure
The second image processing unit may obtain and output an average equivalent value, a minimum equivalent value, and a maximum equivalent value of the screen luminance based on the screen unit image data recorded in the frame buffer. The first image processing unit is capable of amplifying the luminance equivalent value for the image data in the screen unit recorded in the frame buffer and performing signal processing for overall increase and decrease of the luminance equivalent value. The control unit inputs the average equivalent value, the minimum equivalent value, and the maximum equivalent value from the second image processing unit, and the average equivalent value is lower than a predetermined threshold value. If the difference between the maximum equivalent value and the minimum equivalent value is smaller than a predetermined threshold value, the first image processing unit is instructed to increase amplification of the luminance equivalent value, and the luminance equivalent The value Instructing to increase physically, and when the average equivalent value is lower than a predetermined threshold value and the difference between the minimum equivalent value and the maximum equivalent value is larger than a predetermined threshold value, the first image The processing unit is instructed to increase the luminance equivalent value as a whole while giving an instruction to reduce the amplification of the luminance equivalent value.

  When a digital signal generated by analog / digital conversion of an analog signal image for analog display of a television is input to the scaler unit, the scaler unit outputs the image data to each pixel for a display panel having a predetermined number of pixels. The image data is output to a predetermined frame buffer. Then, the second image processing unit calculates and outputs an average equivalent value, a minimum equivalent value, and a maximum equivalent value of the screen luminance based on the screen unit image data recorded in the frame buffer. . The control unit inputs the average equivalent value, the minimum equivalent value, and the maximum equivalent value from the second image processing unit, the average equivalent value is lower than a predetermined threshold value, and the maximum equivalent value and the minimum equivalent value. When the difference from the equivalent value is smaller than a predetermined threshold value, the instruction to increase the luminance equivalent value is given to the first image processing unit, and the luminance equivalent value is set as a whole. Give instructions to increase. Further, when the average equivalent value is lower than a predetermined threshold value and the difference between the minimum equivalent value and the maximum equivalent value is larger than a predetermined threshold value, the luminance equivalent value is given to the first image processing unit. An instruction to increase the luminance equivalent value as a whole is issued while giving an instruction to reduce the value amplification. The first image processing unit performs signal processing for converting a luminance equivalent value into image data recorded in the frame buffer based on an instruction from the control unit.

  As described above, the present invention can automatically perform signal processing according to the characteristics of the image data, and thus can prevent dark images from being blacked out or whited out without manual adjustment by the user. A flat panel display type television receiver or a panel signal generation device can be provided.

  FIG. 1 shows a configuration of a flat panel display type television receiver 10 according to an embodiment of the present invention. In the figure, a flat panel display type television receiver 10 generally includes a tuner 12, a digital signal processing circuit 13, a panel signal generation device 19, a liquid crystal panel 25, and a selector circuit 35, and an IIC bus. The control circuit 26 and the microcomputer I / F 27 are connected via 39. A microcomputer 28 is connected to the microcomputer I / F 27, and the microcomputer 28 can control each circuit of the digital signal processing circuit 13 and the panel signal generator 19 via the microcomputer I / F 27. The liquid crystal panel 25 may be a plasma panel display.

  Here, an operation panel 29, a remote control I / F 30, a ROM 31, a RAM 32, and a backlight drive circuit 33 are connected to the microcomputer 28. The microcomputer 28 stores various control programs stored in the ROM 31 in advance. Is executed while the RAM 32 is used as a work area, and control of each circuit is executed. A backlight unit 34 is connected to the backlight drive circuit 33. Light emitting elements substantially equivalent to the respective pixels of the liquid crystal panel 25 are arranged in a matrix, and each light emitting element is driven by the backlight unit 34 under the control of the microcomputer 28 and emits light with a predetermined light emission luminance.

  The tuner 12 receives a television broadcast signal via the antenna 11. The tuner 12 outputs a television broadcast signal as an analog video signal based on the received television broadcast signal. Further, the liquid crystal television device 10 has an external input terminal 36 for inputting an analog video signal from a VTR, an external input terminal 37 for inputting an analog video signal from an LD player, as external input terminals, And an external input terminal 38 for inputting an analog video signal from the DVD player.

  The tuner 12 and the external input terminals 36 to 38 are connected to the selector circuit 35, and one video signal can be selected from the composite signal output from the tuner 12 and the composite signal input from the external input terminals 36 to 38. It has become. This selection is performed by an operation by a remote controller that is input via an operation panel 29 connected to the microcomputer 28 and a remote controller I / F 30. The composite signal selected by the selector circuit 35 is input to the digital signal processing circuit 13.

  The digital signal processing circuit 13 includes an analog / digital conversion circuit 14, a Y / C separation circuit 15, a chroma decoder circuit 16, an image adjustment circuit 17, and a matrix circuit 18. In this configuration, when the composite signal is input, the analog / digital conversion circuit 14 converts a predetermined signal level range between the white level and the black level in the composite signal into a digital signal having a gradation corresponding to each signal level. To do. Subsequent predetermined signal processing is executed based on this digital signal. The Y / C separation circuit 15 performs separation processing into a Y signal and a C signal based on this digital signal. The separated Y signal and C signal are input to the chroma decoder circuit 16, and are output as YUV signals after predetermined signal processing. The image adjustment circuit 17 adjusts sharpness, color, and TINT for the YUV signal. The matrix circuit 18 performs an RGB matrix conversion process on the YUV signal whose image quality has been adjusted by the image adjustment circuit 17 to generate an RGB signal. The generated RGB signals are input to the panel signal generator 19.

  The panel signal generation device 19 includes a scaler circuit 20, a first image processing unit 21, a second image processing unit 22, a driver circuit 23, a frame buffer 24, and a control circuit 26. . The scaler circuit 20 receives the RGB signal, performs a scaling process on the RGB signal in accordance with the number of pixels of the liquid crystal panel 25 (aspect ratio, m: n), and displays one screen to be displayed on the liquid crystal panel 25. Image data is generated. Then, the image data of one screen is stored in the frame buffer 24. The first image processing unit 21 reads the image data for one screen that has been subjected to the scaling process and stored in the frame buffer 24, amplified the luminance equivalent value, and increased and decreased the luminance equivalent value as a whole. The image data subjected to the signal processing is stored in the frame buffer 24. The second image processing unit 23 performs γ correction on the image data recorded in the frame buffer 24 and records the image data in the frame buffer 24. The driver circuit 23 generates a drive signal to be output to each light emitting element of the liquid crystal panel 25 based on the image data subjected to the signal processing.

  As described above, the composite signal input from the selection destination selected by the selector circuit 35 is input to the analog / digital conversion circuit 14 of the digital signal processing circuit 13 and converted into a digital signal. Here, an example of the video signal input by the analog / digital conversion circuit 14 is shown in FIG. In the figure, the video signal has a horizontal blanking interval and a horizontal synchronizing signal, and the video signal is synthesized between them. Then, the A / D conversion circuit 20 determines the range of the signal level formed by the upper limit voltage Vmax indicating the white level and the lower limit voltage Vmin indicating the black level in the input video signal in a gradation corresponding to each signal level. Convert to digital signal. Specifically, based on the analog / digital conversion range R1 shown in FIG. 2, this signal level range is quantized to 0 to 255 gradations to generate a digital signal S2.

  At this time, if a video signal having a signal level equal to or lower than the lower limit voltage Vmin within a predetermined signal level range is converted, the video signal lower than the lower limit voltage Vmin cannot be accurately quantized. That is, all video signals having a voltage lower than the lower limit voltage Vmin are converted to 0 gradation, and the image of the video signal is blackened. Further, when a video signal having a signal level equal to or higher than the upper limit voltage level Vmax is converted, all signals having a level exceeding Vmax are similarly converted to 255 gradations, resulting in white crushing. As described above, when blackout and whiteout occur in the image, the image quality deteriorates. At present, a method of using signal processing using the luminance of a video signal after being converted into a digital signal is known in order to eliminate blackout of the video. As a technique for this, blackout is eliminated by performing signal processing that amplifies the amplitude of the luminance difference of the image data and raises the gradation of the low luminance region. In this case, in the image data with a small luminance difference, the white crushing in the low luminance region can be eliminated. However, in image data having a large luminance difference, the high luminance region is out of the gradation region by amplifying the amplitude, and on the contrary, whitening occurs. As another method, there is a method of performing signal processing for preventing black crushing in a low luminance region by increasing the entire luminance. In this case as well, in a video signal having a large luminance difference, the high luminance region is out of gradation and white-out occurs. Therefore, in the present embodiment, the control circuit 26 detects the luminance state of the image data displayed on the liquid crystal panel 25 via the second image processing unit 22 and controls the first image processing unit 21. By doing so, it is possible to control the black crushing. Hereinafter, this function will be described.

FIG. 3 shows the configuration of the panel signal generator 19. In the figure, the second image processing unit 22 has an arithmetic circuit 40. The arithmetic circuit 40 is connected to the control circuit 26 via a bus. The arithmetic circuit 40 acquires the RGB signal from the image data of one screen unit recorded in the frame buffer 24, and uses the RGB signal to calculate the average equivalent value, minimum equivalent value, and maximum equivalent value of the luminance of the image data. And calculate. At this time, as a method for generating the luminance Y using the RGB signal data, for example, there is an expression shown below.
Luminance Y = 0.299 x R (red) + 0.587 x G (green) + 0.144 x B (blue)
The equation for calculating the luminance Y is a product-sum operation in which real coefficients are added to RGB image data, and the coefficients may be simplified in consideration of processing in hardware.

  In the present embodiment, the microcomputer 28 compares the average equivalent value, minimum equivalent value, maximum equivalent value, and threshold data T stored in advance in the ROM 31 and performs signal processing according to the comparison result. The value is sent to the first signal processing unit 21. The threshold data T has an average luminance level T1 and a standard level T2 having a maximum equivalent value and a minimum equivalent value of luminance. The microcomputer 28 uses the above-mentioned average equivalent value AVR. A value obtained by comparing Y with T1 and further subtracting the minimum equivalent value from the maximum equivalent value. Find Y and compare it to T2. The first image processing unit 21 performs signal processing on the image data in units of one screen recorded in the frame buffer 24 based on the signal processing value sent from the comparison result. The microcomputer 28 enables real-time signal processing by controlling the signal processing to be performed in units of several tens of ms.

  In FIG. Y <T1 and M.I. An example of a change in image data by signal processing performed when Y <T2 is shown. In the figure, image data 400 indicates image data before processing, and image data 410 indicates image data after processing. In the figure, the above-described upper limit voltage Vmax is a default Vmax that is a predetermined initial value, and the lower limit voltage Vmin is a default Vmin that is a predetermined initial value. The detection result is AVR. Y <T1 and M.I. In the case of Y <T2, it can be predicted that black crushing has occurred in the low luminance region of the image data. Accordingly, in such a case, the microcomputer 28 instructs the first image processing unit 21 to perform signal processing for increasing the amplification of the luminance of the image data to a predetermined value. In response to the instruction, the first image processing unit 21 performs the signal processing on the image data. As a result, black crushing in a low luminance region can be eliminated.

  In FIG. Y ≦ T1 and M.I. An example of a change in image data by signal processing performed when Y> T2 is shown. AVR. Y <T1 and M.I. Even in the case of Y> T2, it can be predicted that blackout has occurred in the low luminance region of the image data. However, in this case, M.I. Since Y> T2, there is a large difference between the maximum equivalent value and the minimum equivalent value, and when the signal amplification is increased, it is expected that the high luminance region exceeds Vmax and white crushing occurs. Therefore, the microcomputer 28 performs image processing for increasing the luminance of the image data to the first image processing unit 21 by a small amount and increasing the luminance as a whole. As a result, it is possible to eliminate black crushing in the low luminance area without causing white crushing in the high luminance area.

  Next, the control process in this embodiment mentioned above is demonstrated. FIG. 6 shows a flow showing the processing contents of this signal processing. When the user selects the presence or absence of signal processing using the operation panel 29 or the remote controller, a selection signal is output to the microcomputer 28 in step S100. The microcomputer 28 accesses the arithmetic circuit 40 and causes the second image processing unit 22 to detect the average equivalent value, the maximum equivalent value, and the minimum equivalent value of the luminance Y of the image data recorded in the frame buffer 24, and The microcomputer 28 is based on AVR. Y and M.M. Y is calculated. (Step S110) Next, the microcomputer 28 accesses the ROM 31, reads the threshold data T1 and T2, and reads the AVR. T is compared with threshold T1. (Step S120) AVR. If Y ≦ T1, the process proceeds to step S130, and AVR. If Y> T1, the process proceeds to step S160. In step S <b> 160, the microcomputer 28 outputs the image data to the second image processing unit 22. Next, in step S140, the microcomputer 28 determines the M.M. Y and T2 are compared. If Y> T2, the process proceeds to step S140. If Y <T2, the process proceeds to step S150. Next, in step S140, the microcomputer 28 determines a signal processing value that increases the amplification of the image data, and performs signal processing using the signal processing value determined in step S140 in step S160. The image processing unit 21 is instructed. In step S150, the microcomputer 28 determines a signal processing value that increases the overall luminance while amplifying the image data by a small amount, and performs signal processing using the signal processing value in step S160. An instruction is issued to the first image processing unit 21.

  In the above-described embodiment, the luminance state of the image data for each screen recorded in the frame buffer 24 is used as the signal processing value determination condition. On the other hand, it is also possible to perform signal processing in which the image data is divided into predetermined areas and the luminance state in each area is used as a determination condition. In particular, if there is an extremely bright area in the entire dark background image, the background image and the bright area are divided, and by applying separate signal processing, It is also possible to prevent white crushing in extremely bright areas. Therefore, in the embodiment of the present invention, the liquid crystal television receiver 10 is provided with the following area division function, and after performing signal processing in units of one screen, the predetermined area is divided and is suitable for the area. The signal processing value in the unit of one screen is corrected so that the signal processing can be performed.

  FIG. 7 shows the configuration of the control circuit 26 in the embodiment of the present invention. The control circuit 26 of the present embodiment associates the size detection circuit 41 that detects the size of the image display unit of the liquid crystal panel 25 and the division method of the image display unit of the liquid crystal panel 25 with the size of the liquid crystal panel 25. The division correspondence holding unit 42 to be determined is included. The size detection circuit 41 is connected to the liquid crystal panel 25 and detects the size of the image display unit of the liquid crystal panel 25. The size detection circuit 41, the microcomputer 28, and the division correspondence holding unit 42 are connected via a bus. In this embodiment, the division correspondence holding unit has a division table composed of the size D1 of the liquid crystal panel 25 and the number D2 of division regions. In such a configuration, the microcomputer 28 determines an area dividing method based on the size of the liquid crystal panel 25.

  In the present embodiment, the microcomputer 28 determines a signal processing value H that eliminates black crushing for image data of one screen unit recorded in the frame buffer 24. The method for eliminating the black crushing is performed using the same method as that in the flowchart of FIG. 9 described above. Next, when the size detection circuit 41 detects the size of the liquid crystal panel 25, it sends this to the microcomputer 28 as a size signal. Next, upon receiving the size signal, the microcomputer 28 accesses the division correspondence holding unit 42 and reads the division number D2 corresponding to the size signal D1 from the division table. Next, the microcomputer 28 instructs the scaler circuit 20 to divide the image data of one screen unit recorded in the frame buffer 24 by D2. In response to this, the scaler circuit 20 executes the instruction and records the divided areas in the frame buffer unit 24. FIG. 8 is a diagram in which an image displayed on the liquid crystal panel 25 is divided into nine equal squares by the scaler circuit 20.

  Furthermore, the microcomputer 28 causes the second image processing unit 22 to obtain the average equivalent value, the minimum equivalent value, and the maximum equivalent value of the luminance for each of the divided areas based on the RGB signals, and to perform the second image processing. The unit 22 compares the average equivalent value, the minimum equivalent value, and the maximum equivalent value for each area with a predetermined threshold T3 recorded in advance in the ROM 31. Then, the signal processing correction is output to the first image processing unit 21 based on the comparison result. While preventing the background from being crushed, it is possible to prevent the divided areas from being crushed.

  FIG. 9 shows the flow of signal processing value output processing performed by the microcomputer 28 in this embodiment. In steps S <b> 200 to S <b> 206, the microcomputer 28 determines a signal processing value for the image data for each screen recorded in the frame buffer 24. In steps S200 to S206 for determining the signal processing value, the signal processing value is determined in the same manner as in the flowchart of FIG. In step S210, it is determined whether to perform signal processing for each region. At this time, the user can select whether or not to perform the signal processing for each region by operating the operation panel 29 or operating the remote control. When the user selects to perform signal processing for each area, the size detection circuit 41 detects the size of the liquid crystal panel 25 and sends a size signal to the microcomputer 28 based on the size. Receiving the magnitude signal, the microcomputer 28 accesses the division correspondence holding unit 42 in step S220. In this embodiment, the division correspondence holding unit 42 assumes that the division number D2 is 3 × 3 and 9 divisions when the size of the liquid crystal panel 25 is 32 inches. After reading the data, the microcomputer 28 instructs the scaler circuit 20 to divide the image data recorded in the frame buffer 24 into nine areas. In response, the scaler circuit divides the image data into nine regions.

  Next, in step S230, the microcomputer 28 obtains the average equivalent value, the minimum equivalent value, and the maximum equivalent value of the luminance Y for each of the nine divided areas, and based on this, the AVR. Y and M.M. Y is calculated. Next, in step S230, the microcomputer 28 causes the AVR. Y (Ri) and region T3 are compared, and AVR. If Y (Ri)> T3, the process proceeds to step S231. In step S231, the microcomputer 28 sets the M.M. Y (Ri) is compared with T4 recorded in the ROM 31.

  FIG. 10 shows that AVR. Y (Ri)> T3 and M.I. An example of a change when signal processing is performed on a region where Y (Ri)> T4 is shown. The above region is AVR. Y (Ri)> T3 and M.I. In other words, Y (Ri)> T4, that is, a region having a higher average luminance equivalent value and a larger luminance gradation than other regions. Therefore, the microcomputer 28 determines a signal processing value that amplifies the amplitude by a small amount and increases the overall luminance so that the luminance Y of the region does not exceed the default Vmax. In step S235, the microcomputer 28 instructs the first image processing unit 21 of the signal processing value.

  FIG. 11 shows AVR. Y (Ri)> T3 and M.I. An example of a change when signal processing is performed on an area where Y (Ri) <T4 is shown. The above region is AVR. Since Y (Ri)> T3, the average equivalent value of the luminance is higher than in other areas, and when the signal processing value H in units of one screen is executed, there is a possibility that the area is crushed white. Therefore, the microcomputer 28 determines a signal processing value for amplifying the amplitude so that the luminance Y of the region does not exceed the default Vmax. Further, in step S235, the microcomputer 28 instructs the first image processing unit 21 on the signal processing value, and the first image processing unit 21 executes signal processing in response to the instruction.

  In the embodiment described above, there is a method of determining the signal processing value as a condition of the signal processing value of each region so that the difference in luminance Y between adjacent regions does not become larger than a predetermined threshold. Thereby, it is possible to prevent variations in luminance between regions after signal processing by keeping the difference in luminance Y of each region after signal processing constant. In the present embodiment, the signal processing value is detected using the average luminance of the area, but may be detected using pixel data of each pixel constituting each area.

  In the embodiment described above, the microcomputer 28 determines the difference between the average equivalent value of the luminance Y for each screen after the signal processing and the average equivalent value of the luminance Y of each area after the signal processing, and the threshold value recorded in the ROM 31 in advance. By comparing with T5, the luminance difference between the regions is detected. FIG. 12 shows an example of a video data image subjected to signal processing for each area displayed on the liquid crystal panel 25. In FIG. 12, it is assumed that the nine divided areas are R1 to R9 in order from the upper left, and the image data in FIG. 13 is subjected to individual signal processing for the two areas R2 and R5 and the other areas. The average equivalent value of the luminance of each area after the signal processing is expressed as HAVR. Assuming Y (Ri) (i: 1 to 9), in the signal processing in the present embodiment, the difference between the average luminance after the signal processing HAVR. Y (ΣR) -HAVR. Y (R2) and T5 are compared, and the signal processing value is further corrected according to the condition.

  FIG. 13 shows a flow of signal processing value output processing performed by the microcomputer 28 in this embodiment. In step S300 to step S335, the microcomputer 28 determines the signal processing value for each area by the same method as that in the flowchart of FIG. 10, and then executes the signal processing value for each area in step S340. Give instructions. Next, in step S341, the microcomputer 28 detects the luminance of one screen unit after the signal processing and the luminance of each area recorded in the frame buffer 24, and calculates the average equivalent value HAVR. Y (ΣR) and the average equivalent value HAVR. Y (Ri) is obtained. Next, in step S342, the microcomputer 28 reads the threshold value T5 recorded in the ROM 31, and the difference between both average luminances HAVR. Y (ΣR) -HAVR. Y (Ri) is compared with threshold value T5.

| HAVR. Y (ΣR) -HAVR. Y (Ri) | <T5
The signal processing value is not corrected for the region to be, and the process proceeds to step S344.
| HAVR. Y (ΣR) -HAVR. Y (Ri) | <T5
After the signal processing is corrected so as to decrease the signal processing value for the region to be, the microcomputer 28 instructs the first image processing unit 21 to perform the signal processing again for the region in step S344. . Finally, in step S345, the above signal processing is repeated until the entire area is executed.

  According to one embodiment of the present invention, after obtaining an instruction for the signal processing to the first image processing unit in units of one screen, the second image processing unit is provided with a plurality of areas constituting one screen. The average equivalent value, the minimum equivalent value, and the maximum equivalent value are obtained for each divided area, and the first equivalent value for each area is determined based on the average equivalent value, the minimum equivalent value, and the maximum equivalent value. An instruction for the signal processing for one image processing unit is obtained, a new instruction is obtained from the instruction for each screen and the instruction for each area, and an instruction for the signal processing for the first image processing unit is obtained. It is characterized by putting out.

  For each area divided into a plurality of areas constituting one screen by the second image processing unit after the control unit has requested the signal processing instruction to the first image processing unit in one screen unit. The average equivalent value, the minimum equivalent value, and the maximum equivalent value are obtained. Further, the control unit obtains an instruction for the signal processing for the first image processing unit for each region based on the average equivalent value, the minimum equivalent value, and the maximum equivalent value, and A new instruction is obtained from the instruction and the instruction for each region, and the signal processing instruction is issued to the first image processing unit.

  According to one embodiment of the present invention, when the average equivalent value obtained for each area is larger than a predetermined threshold, the control unit gives the instruction obtained for each area to the area. It is corrected, and an instruction is issued so as to reduce the extent to which the luminance equivalent value is increased in the first image processing unit.

  For each area divided into a plurality of areas constituting one screen by the second image processing unit after the control unit has requested the signal processing instruction to the first image processing unit in one screen unit. The average equivalent value, the minimum equivalent value, and the maximum equivalent value are obtained, and a signal processing value for each region is determined based on the average equivalent value. Further, when the average equivalent value obtained for each area is larger than a predetermined threshold, the control unit corrects the instruction obtained for each area for the area, and the first image is corrected. The processing unit is characterized in that an instruction is issued to reduce the degree of increase in the luminance equivalent value.

  According to an embodiment of the present invention, the control unit includes a size detecting unit that detects the size of the display panel, and a size and a division that have a tendency to increase the number of divisions as the size of the display panel increases. And a division correspondence holding means for holding the correspondence corresponding to the area to be divided, and obtaining a region to be divided by the division correspondence holding means based on the size of the display panel detected by the size detection means. The above instruction is obtained using the obtained divided area.

  The control unit has a correspondence relationship that associates a size detection unit that detects the size of the display panel, a size that tends to increase the number of divisions as the size of the display panel increases, and a region to be divided. It is comprised from the division | segmentation corresponding | compatible relationship holding means to hold | maintain. The control unit obtains a region to be divided by the division correspondence holding unit based on the size of the display panel detected by the size detection unit after determining the signal processing value of the image data of one screen unit, The signal processing value for each area is obtained using the obtained divided area.

  According to an embodiment of the present invention, the control unit switches between presence and absence of signal processing performed in the first image processing unit.

  The control unit is configured to switch presence / absence of signal processing performed in the first image processing unit by operating either a remote controller or an operation panel via a remote controller I / F.

  The control unit causes the second image processing unit to obtain the average equivalent value, minimum equivalent value, and maximum equivalent value of the luminance based on the image data recorded in the frame buffer, and based on this, the average equivalent value By comparing the minimum equivalent value and the maximum equivalent value with a predetermined threshold value, causing the first image processing unit to perform signal processing, and in some cases, dividing the image data and performing signal processing for each region, the image It becomes possible to perform signal processing according to the data state, and it is possible to improve the image quality by controlling the blackout of the image data.

It is the block diagram which showed the structure in one Embodiment of the flat display television apparatus concerning this invention. It is a figure which shows an analog / digital conversion range. It is a block diagram of the signal generation apparatus for panels. AVR. Y <T1 and M.I. It is a figure which shows an example of the change of the image data by the signal processing performed when Y <T2. AVR. Y <T1 and M.I. It is a figure which shows the change of the image data by the signal processing performed when Y> T2. It is a flowchart of the process which outputs a signal output process value. It is a block diagram of a control circuit. It is the figure which divided the image data displayed on a liquid crystal panel into 9 equal squares. It is a flowchart of the process which outputs a signal output process value. AVR. Y (Ri)> T3 and M.I. It is a figure which shows the change of the signal processing with respect to the area | region which is Y (Ri)> T4. AVR. Y (Ri)> T3 and M.I. It is a figure which shows the change of the signal processing with respect to the area | region which is Y (Ri) <T4. It is a figure which shows an example of the image in which the signal processing was implemented for every area | region displayed on a liquid crystal panel. It is a flowchart of the process which outputs a signal output process value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Flat panel display type television receiver 11 ... Antenna 12 ... Tuner 13 ... Digital signal processing circuit 14 ... Analog / digital conversion circuit 15 ... Y / C separation circuit 16 ... Chroma decoder circuit 17 ... Image adjustment circuit 18 ... Matrix circuit DESCRIPTION OF SYMBOLS 19 ... Panel signal generator 20 ... Scaler circuit 21 ... First image processing part 22 ... Second image processing part 23 ... Driver circuit 24 ... Frame buffer 25 ... Liquid crystal panel 26 ... Control circuit 27 ... Microcomputer I / F
28 ... Microcomputer 29 ... Operation panel 30 ... Remote control I / F
31 ... ROM
32 ... RAM
33 ... Backlight drive circuit 34 ... Backlight 35 ... Selector circuit 36 ... External input terminal 37 ... External input terminal 38 ... External input terminal 39 ... IIC bus 40 ... Arithmetic circuit 41 ... Size detection circuit 42 ... Division correspondence holding unit

Claims (7)

A tuner that receives television through an antenna, a digital signal processing circuit that converts an analog video signal of the television received by the tuner into a digital video signal and generates an RGB signal based on the digital video signal, and based on the RGB signal A scaler circuit that generates image data for a display panel having a predetermined number of pixels and records image data for one screen in a predetermined frame buffer;
A first image processing unit in charge of performing signal processing including image quality adjustment on the image data based on the image data of the screen unit recorded in the frame buffer;
A second image processing unit in charge of performing signal processing including γ correction on the image data based on the image data recorded in the frame buffer;
A driver circuit that generates a drive signal for driving the display panel based on the image data recorded in the frame buffer;
A flat panel display television receiver comprising a control unit for controlling the scaler, the first image processing unit, the second image processing unit, and the driver circuit at predetermined time intervals. ,
The second image processing unit may obtain and output an average equivalent value, a minimum equivalent value, and a maximum equivalent value of the screen luminance based on the screen unit image data recorded in the frame buffer. Is possible,
The first image processing unit can amplify the luminance equivalent value for the image data in the screen unit recorded in the frame buffer, and perform signal processing for overall increase and decrease of the luminance equivalent value.
The control unit inputs the average equivalent value, the minimum equivalent value, and the maximum equivalent value from the second image processing unit,
When the average equivalent value is lower than a predetermined threshold value and the difference between the maximum equivalent value and the minimum equivalent value is smaller than a predetermined threshold value, the luminance equivalent value is set to the first image processing unit. While giving an instruction to increase amplification, an instruction to increase the luminance equivalent value as a whole is given.
Further, when the average equivalent value is lower than a predetermined threshold value and the difference between the minimum equivalent value and the maximum equivalent value is larger than a predetermined threshold value, the luminance equivalent value is given to the first image processing unit. An instruction to increase the luminance equivalent value is issued while giving an instruction to reduce the amplification of the value, and the control unit includes a size detection circuit for detecting the size of the display panel, and the display panel. A division correspondence holding unit that holds a correspondence relationship that associates a size having a tendency to increase the number of divisions with an increase in size and a region to be divided; Find the area to be divided by the division correspondence holding unit based on the size, and
After obtaining an instruction of the signal processing to the first image processing unit in one screen unit, the average equivalent value for each region divided into a plurality of regions constituting one screen by the second image processing unit. And calculating the minimum equivalent value and the maximum equivalent value, and performing the signal processing for the first image processing unit for each region based on the average equivalent value, the minimum equivalent value, and the maximum equivalent value. Obtaining an instruction, obtaining a new instruction from the instruction for each screen and the instruction for each area, and issuing an instruction for the signal processing to the first image processing unit,
When the average equivalent value obtained for each area is larger than a predetermined threshold value, the instruction obtained for each area is corrected for the area, and the first image processing unit corrects the luminance. Tell them to reduce the amount of increase,
In addition, the control unit obtains the instruction so that the difference in the degree of signal processing in the first image processing unit for each region between adjacent regions does not become larger than a predetermined threshold value.
And the flat panel display type television receiver characterized by switching the presence or absence of the signal processing performed in said 1st image processing part. A digital signal obtained by analog / digital conversion based on an analog video signal for analog display of a television is input and converted to a digital video signal of each pixel for a display panel having a predetermined number of pixels, and is stored in a predetermined frame buffer for one screen. A scaler unit for recording the image data, and a first image processing unit in charge of performing signal processing including image quality adjustment on the image data based on screen-unit image data recorded in the frame buffer; ,
A second image processing unit in charge of performing signal processing including γ correction on the image data based on the image data recorded in the frame buffer;
A driver unit that generates a drive signal for driving the display panel based on the image data recorded in the frame buffer;
A display panel signal generation device comprising a control unit for controlling the scaler unit, the first image processing unit, the second image processing unit, and the driver unit at predetermined time intervals, respectively.
The second image processing unit may obtain and output an average equivalent value, a minimum equivalent value, and a maximum equivalent value of the screen luminance based on the screen unit image data recorded in the frame buffer. Is possible,
The first image processing unit can amplify the luminance equivalent value for the image data in the unit of screen recorded in the frame buffer, and perform signal processing for overall increase and decrease of the luminance equivalent value.
The control unit inputs the average equivalent value, the minimum equivalent value, and the maximum equivalent value from the second image processing unit,
When the average equivalent value is lower than a predetermined threshold value and the difference between the maximum equivalent value and the minimum equivalent value is smaller than the predetermined threshold value, the luminance equivalent value is determined for the first image processing unit. While giving an instruction to increase amplification, an instruction to increase the luminance equivalent value as a whole is given.
Further, when the average equivalent value is lower than a predetermined threshold value and the difference between the minimum equivalent value and the maximum equivalent value is larger than a predetermined threshold value, the luminance equivalent value is given to the first image processing unit. A display panel signal generation device characterized by issuing an instruction to increase the luminance equivalent value as a whole while giving an instruction to reduce the value amplification.   The control unit obtains an instruction for the signal processing to the first image processing unit in units of one screen, and then, for each area divided into a plurality of areas constituting one screen by the second image processing unit. To obtain the average equivalent value, the minimum equivalent value, and the maximum equivalent value, and the first image processing unit for each region based on the average equivalent value, the minimum equivalent value, and the maximum equivalent value. An instruction for the signal processing for the first image processing unit is obtained by obtaining a new instruction from the instruction for each screen and the instruction for each area. The display panel signal generation device according to claim 2.   When the average equivalent value obtained for each area is larger than a predetermined threshold, the control unit corrects the instruction obtained for each area for the area, and performs the first image processing. 4. The display panel signal generation device according to claim 3, wherein an instruction is issued so as to reduce the degree of increase of the luminance equivalent value in the unit.   The said control unit calculates | requires the said instruction | indication so that the difference of the level which signal-processes in the said 1st image processing unit for every area | region between adjacent areas may not become larger than a predetermined threshold value. Or the signal generation apparatus for display panels in any one of Claim 4.   The control unit has a correspondence relationship between a size detection unit that detects the size of the display panel, and a size in which the number of divisions tends to increase as the size of the display panel increases and a region to be divided. A division correspondence holding means for holding the display panel, and obtaining a region to be divided by the division correspondence holding means based on the size of the display panel detected by the size detection means, and using the obtained divided region. 6. The display panel signal generating apparatus according to claim 3, wherein the instruction is obtained.   7. The display panel signal generation device according to claim 2, wherein the control unit switches presence / absence of signal processing performed in the first image processing unit.

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