JP2012053087A - Phase adjustment device and phase adjustment method and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase adjustment device and a phase adjustment method for making an image display device display a clear image and an image display device equipped with the phase adjustment device.SOLUTION: Disclosed is a phase adjustment method for executing: sampling clock generation processing (S101) for generating a sampling clock; AD conversion processing (S106) for sampling an input analog video signal, and for converting the analog video signal into a digital video signal; phase shift processing (S201) for shifting the phase of the sampling clock; subdivision processing (S216) for subdividing a display image displayed based on the digital video signal output in the step S106 into a plurality of display areas; shift quantity determination processing (S301) for determining the value of the optimal phase shift quantity for each display area; and phase optimization processing (S305) for setting the value of the optimal phase shift quantity of the whole display image based on the value of the optimal phase shift quantity of each display area determined by the shift quantity determination processing.

Description

  The present invention relates to an image display device such as a projector or a display that converts an analog video signal into a digital video signal and displays it, and more particularly to a phase adjustment device and a phase adjustment method that automatically and optimally adjust image quality. .

  2. Description of the Related Art Today, data projectors and displays are often used as image display devices for displaying personal computer (PC) screens, video images, and images based on image data stored in a memory card.

  This type of image display apparatus is connected to a video signal source such as a PC or a workstation, and displays an image based on an analog video signal or a digital video signal supplied from the video signal source. When the display pixel clock frequency on the video signal source side is known, the sampling clock frequency can be accurately adjusted to the display pixel clock on the video signal source side based on the information.

  However, when the input video signal is an analog signal, the image display device cannot acquire information related to the display pixel clock on the video signal source side in advance. Therefore, the frequency of the sampling clock does not match the frequency of the display pixel clock on the video signal source side, and a deviation occurs between the sampling clock for sampling the video signal and the video signal, and as a result, the image is displayed correctly. Can not do.

  The deviation between the sampling clock and the video signal can be adjusted by the user by using the phase adjustment function provided in the image display device and adjusting the frequency of the sampling clock while viewing the displayed image. The adjustment of the clock frequency is troublesome for the user.

  Therefore, various devices that can automatically adjust the frequency of the sampling clock have been proposed. For example, in Japanese Patent Laid-Open No. 2002-33939 (Patent Document 1), image data digitized by an AD converter is temporarily stored in a memory, and the current field image data and the image of the previous field read from the memory are read by the difference detection unit. There has been proposed a phase adjusting device that compares data with each other to obtain a difference between both fields and shifts the phase of the sampling clock so that the difference becomes a predetermined value or less.

JP 2002-33939 A

  Various devices that automatically adjust the phase of the sampling clock as described in the above document have been proposed. However, in order to find and adjust the optimum value from the information of the entire image, there is little change in gradation such as natural images. In the case where there is, there is a problem that the phase is not optimally adjusted in the entire screen, and as a result, the image is not displayed correctly.

  The present invention has been made in view of such problems of the prior art, and divides the entire display screen into a plurality of display areas, and among the plurality of display areas, a display area having a large gradation change amount. For the purpose of providing a phase adjusting device and a phase adjusting method capable of displaying a beautiful image on an image display device by adjusting the phase with emphasis on the phase, and an image display device including the phase adjusting device. Yes.

  The phase adjustment apparatus according to the present invention includes a sampling clock generation unit that generates a sampling clock, an AD conversion unit that samples an input analog video signal with the sampling clock and converts the sampled video signal into a digital video signal, and a phase of the sampling clock A phase shift means for shifting the display image, a partition means for partitioning a display image displayed based on the digital video signal output from the AD conversion means into a plurality of display areas, and an optimum phase shift amount for each display area Shift amount determining means for determining a value, and phase optimizing means for setting the value of the optimum phase shift amount for the entire display image based on the value of the optimum phase shift amount for each display area determined by the shift amount determining means And.

  The phase adjustment device according to the present invention is integrated by a pixel brightness difference integration unit that integrates pixel brightness differences between adjacent display pixels of a horizontal line in a display image for each display area, and the pixel brightness difference integration unit. An area designating unit for designating a display area having a total pixel brightness difference exceeding a predetermined value, and the phase optimization unit is based on the value of the optimum phase shift amount of the display area designated by the area designating unit. Thus, it is preferable to set the value of the optimum phase shift amount for the entire display image.

  Further, in the phase adjustment apparatus according to the present invention, the area designating unit designates a display area in a plurality of levels according to the total pixel brightness difference accumulated by the pixel brightness difference accumulation unit, and the phase optimization The converting means sets the value of the optimum phase shift amount of the entire display image by averaging the value of the optimum phase shift amount of the display area specified by the area specifying means with a weight according to the level. It is more preferable.

  The phase adjusting device according to the present invention captures the amount of change in the gradation value for each frame in each display pixel in the display area partitioned by the partitioning means, and controls all the display pixels in each display area. Frame lightness difference integrating means for integrating the frame lightness difference for each display area; and area designating means for designating a display area in which the total frame lightness difference integrated by the frame lightness difference integrating means exceeds a predetermined value. The phase optimizing unit may employ a configuration in which an optimum phase shift amount value of the entire display image is set based on the optimum phase shift amount value of the display area designated by the area designating unit. .

  In this case, the area designating unit designates a display area divided into a plurality of levels according to the total frame lightness difference accumulated by the frame lightness difference accumulating unit, and the phase optimization unit comprises the area designating unit. It is preferable to set the value of the optimum phase shift amount of the entire display image by averaging the value of the optimum phase shift amount of the display area designated by the weighting according to the level.

  Furthermore, the phase adjusting apparatus according to the present invention specifies a character recognition unit that recognizes characters in the display area partitioned by the partition unit, and a display area in which the number of characters recognized by the character recognition unit exceeds a predetermined value. And an area designating unit that sets the optimum phase shift amount value of the entire display image based on the optimum phase shift amount value of the display area designated by the area designating unit. A configuration can be employed.

  In this case, the area designating unit designates a display area divided into a plurality of levels according to the number of characters recognized by the character recognizing unit, and the phase optimization unit comprises the display designated by the area designating unit. It is preferable to set the value of the optimum phase shift amount of the entire display image by averaging the value of the optimum phase shift amount of the area with weighting according to the level.

  The phase adjustment method according to the present invention includes a sampling clock generation process for generating a sampling clock, an AD conversion process for sampling an input analog video signal with the sampling clock and converting it into a digital video signal, and the sampling clock. A phase shift process for shifting the phase of the image, a partition process for partitioning a display image displayed based on the digital video signal output in the AD conversion process into a plurality of display areas, and an optimum phase shift for each display area A phase optimum that sets the optimum phase shift amount value for the entire display image based on the shift amount decision process for determining the amount value and the optimum phase shift amount value for each display area determined by the shift amount decision process And performing the conversion process.

  In addition, the phase adjustment method according to the present invention is integrated by a pixel brightness difference integration process that integrates pixel brightness differences between adjacent display pixels on a horizontal line in a display image for each display area, and the pixel brightness difference integration process. And an area designation process for designating a display area in which the total pixel brightness difference exceeds a predetermined value, and in the phase optimization process, an optimum phase shift amount value of the display area designated in the area designation process is set. Based on this, it is preferable to set the value of the optimum phase shift amount for the entire display image.

  Further, in the phase specifying method according to the present invention, in the area specifying process, the display area is specified in a plurality of levels according to the total pixel brightness difference integrated in the pixel brightness difference integrating process, and the phase optimization In the conversion processing, the optimal phase shift amount value of the display area specified in the area specification processing is averaged by weighting according to the level, thereby setting the optimal phase shift amount value of the entire display image. It is more preferable.

  Then, the phase adjustment method according to the present invention takes in the amount of change in the gradation value for each frame in each display pixel in the display area partitioned by the partitioning process, and calculates all the display pixels in each display area. A frame brightness difference integration process for integrating the frame brightness difference for each display area; and an area specification process for specifying a display area in which the total frame brightness difference integrated in the frame brightness difference integration process exceeds a predetermined value. And the phase optimization process may set the optimum phase shift amount value of the entire display image based on the optimum phase shift amount value of the display area designated in the area designation process.

  In this case, in the area designating process, a display area is designated in a plurality of levels according to the total frame lightness difference accumulated in the frame lightness difference integrating process, and the area designating process is performed in the phase optimization process. It is preferable to set the value of the optimum phase shift amount of the entire display image by averaging the value of the optimum phase shift amount of the display area specified in (1) with weighting according to the level.

  The phase adjustment method according to the present invention also includes a character recognition process for recognizing characters in the display area partitioned by the partition process, and a display area in which the number of characters recognized by the character recognition process exceeds a predetermined value. In the phase optimization process, the optimum phase shift amount value of the entire display image is set based on the optimum phase shift amount value of the display area designated in the area designation process. There is also a case.

  In this case, in the area designation process, display areas are designated in a plurality of levels according to the number of characters recognized in the character recognition process, and the display designated in the area designation process is designated in the phase optimization process. It is preferable to set the value of the optimum phase shift amount of the entire display image by averaging the value of the optimum phase shift amount of the area with weighting according to the level.

  The image display device of the present invention includes a phase adjustment device and a display device control unit. The phase adjustment device is any one of the phase adjustment devices described above, and the display device control unit includes the phase control device. The adjusting device is controlled to adjust the phase.

  According to the present invention, a clear image can be obtained by dividing the entire display screen into a plurality of display areas and adjusting the phase with a focus on a display area having a large gradation change amount among the plurality of display areas. A phase adjustment device and a phase adjustment method that can be displayed on a display device, and an image display device including the phase adjustment device can be provided.

It is a functional block diagram of the phase adjustment apparatus which concerns on the Example of this invention. It is a flowchart which shows the flow of the phase adjustment method performed by the phase adjustment apparatus which concerns on the Example of this invention. It is a time chart which shows operation | movement of the image conversion part which concerns on the Example of this invention. It is a schematic diagram which shows the display pixel group in a part of display screen of the image display apparatus which concerns on the Example of this invention. It is a schematic diagram which shows the display screen of the image display apparatus which concerns on the Example of this invention. It is a table | surface which shows the level for every display area memorize | stored in RAM in the image display apparatus based on the Example of this invention, the optimal phase (number of steps), and weight information. 1 is an external perspective view showing a projector as an image display device according to an embodiment of the present invention. It is a functional block diagram of a projector as an image display apparatus according to an embodiment of the present invention.

  Hereinafter, modes for carrying out the present invention will be described. The phase adjustment apparatus 1 includes an AD converter 11 serving as an AD conversion unit, a sampling clock generation unit, a phase shift unit, a pixel brightness difference calculation unit, a partition unit, a pixel brightness difference integration unit, an area designation unit, a shift amount determination unit, And an image conversion unit 10 having an image control unit 12 functioning as a phase optimization unit. In addition, the phase adjustment device 1 includes storage means such as a ROM 16, a RAM 14, and a video RAM 13.

  The image control unit 12 also functions as a phase shift unit that generates a sampling clock as a sampling clock generation unit and sequentially shifts the phase of the sampling clock for each frame in predetermined stages.

  The AD converter 11 is an AD conversion means for sampling an input analog video signal with a sampling clock and converting it into a digital video signal. Then, the image control unit 12 partitions the display image displayed based on the digital video signal output from the AD converter 11 as partitioning means into a plurality of display areas 2.

  Further, the image control unit 12 calculates a pixel brightness difference that is a difference in gradation value between adjacent display pixels of the horizontal line in the display image as a pixel brightness difference calculating unit, and for each display area 2 as a pixel brightness difference integrating unit. The pixel lightness difference is integrated into. Then, the image control unit 12 designates the display area 2 as a plurality of levels according to the accumulated total pixel brightness difference as area designation means.

  Further, the image control unit 12 determines the value of the optimum phase shift amount for each display area 2 as the shift amount determining means, and based on the value of the optimum phase shift amount for each display area 2 determined as the phase optimization means. Specifically, the value of the optimum phase shift amount of the entire display image is set by averaging the value of the optimum phase shift amount of the display area designated for each level with weighting according to the level.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram of a phase adjustment apparatus 1 according to an embodiment of the present invention. The phase adjustment device 1 includes an image conversion unit 10 having an AD converter 11 and an image control unit 12, and a video RAM 13, a RAM 14, and a ROM 16.

  The image forming unit 15 is a display unit for displaying a digital image such as a liquid crystal display panel or a plasma display panel. When the phase adjusting device 1 is mounted on a projector, the image forming unit 15 is a DMD (digital・ Display devices such as micromirror devices and liquid crystal plates.

  The phase adjustment device 1 is incorporated in an image display device such as a projector or a display, and has a function of adjusting the phase of a video signal for displaying an image on the image forming unit 15 to an optimum one. It functions as image conversion means for transmitting a predetermined video signal to the image forming unit 15 of the image display device based on a video signal input from the outside, and causing the image forming unit 15 to display an image.

  The image control unit 12 includes an MPU, a PLL circuit, and the like serving as calculation means, and controls the entire circuit operation in the phase adjustment device 1 based on a program stored in the ROM 16. Means. The image control unit 12 functions as sampling clock generation means for generating a sampling clock using the horizontal synchronization signal separated from the input video signal as a reference signal.

  The AD converter 11 converts an analog video signal input from a video signal source 9 such as a PC or a workstation into a digital video signal, and at the rising or falling timing of the sampling clock generated by the image control unit 12. It is AD conversion means for sampling and converting the sampled video signal for one pixel into a digital value.

  The image control unit 12 develops display image information in the video RAM 13 based on the digital video signal output from the AD converter 11 and causes the image forming unit 15 to display the display image. The image control unit 12 also functions as partitioning means for partitioning the display image into a plurality of display areas.

  The image control unit 12 functions as a phase shift unit that sequentially shifts the phase of the sampling clock generated as the sampling clock generation unit by one step that is a predetermined phase change amount over one period.

  After performing the phase shift over one period, the image control unit 12 determines an optimum value of the phase shift amount for each display area partitioned as the shift amount determining means, and the display area as the phase optimizing means. Based on the value of the optimum phase shift amount for each, a process for setting the value of the optimum phase shift amount of the entire display image is executed.

  Hereinafter, the phase adjustment method characterized by the phase adjustment apparatus 1 according to the embodiment of the present invention will be described with reference to the flowchart of FIG. In the following description, it is assumed that the input video signal is still image information.

  In the phase adjustment device 1, the user starts phase adjustment by operating the phase adjustment switch, and the image control unit 12 executes processing for generating a sampling clock (step S101). Then, the AD converter 11 samples the input analog video signal with the sampling clock generated in the sampling clock generation process (step S101), and executes an AD conversion process (step S106) for conversion into a digital video signal.

  That is, as shown in FIG. 3, the digital data stored in the PC that is the video signal source 9 is D / A converted in the PC and output as an analog video signal. Then, the image control unit 12 of the phase adjusting device 1 samples the analog video signal at the rising timing of the sampling clock and converts it into a digital video signal. Then, the image control unit 12 executes a process of developing image information to be displayed on the image forming unit 15 on the video RAM 13 from the obtained digital video signal.

  Then, the image control unit 12 displays an image display process (step S111) based on the image information developed in the video RAM 13, that is, based on the digital video signal output in the AD conversion process (step S106). ). Here, the image control unit 12 executes a process (step S113) of storing the gradation value for each display pixel, which is image information for displaying the display image, in the RAM.

  Then, the image control unit 12 executes a phase shift process (step S201) for shifting the phase of the sampling clock. In the phase shift process (step S201), the sampling clock is shifted by a required time. As a method of shifting, for example, a delay circuit using multistage transistors can be configured, and one period can be divided into 32 steps and sequentially shifted one step at a time.

  Then, the image control unit 12 executes a process (step S211) for determining whether or not the one-phase phase shift is completed. If the one-phase phase shift is not completed, the process returns to step S106 and the next Sampling in the frame is performed (step S106), and processing similar to that described above (steps S111 to 201) is executed. That is, the image control unit 12 stores the gradation value data for each display pixel in the RAM 14 for each frame, and repeats the operation of shifting the phase of the sampling clock by a predetermined amount over one period.

  When the phase shift process (step S201) is repeated and the phase shift for one cycle (32 steps) is completed, the process proceeds to the next step, and the image control unit 12 stores one cycle (32 steps) stored in the RAM 14. Pixel brightness difference calculation processing (step S215) for calculating, for each frame, a difference in tone value between adjacent display pixels on a horizontal line constituting a display image of each frame based on the tone value data of each frame. ).

  This pixel brightness difference calculation process (step S215) will be described with reference to FIG. FIG. 4 is a schematic diagram showing a plurality of display pixels constituting a part of the display image, and one pixel collectively describes three points of red, green, and blue as one pixel. In the following description, it is assumed that the gradation values of red, green, and blue are all equal. (Actually, the gradation values of red, green, and blue are respectively set so that various shades can be expressed.)

  As shown in the figure, for example, the gradation value of the first display pixel 21 sampled in a predetermined frame is 0 (black), and the gradation value of the second display pixel 22 adjacent to the right is 255 (white). In this case, the gradation value difference (pixel brightness difference) between the first display pixel 21 and the second display pixel 22 is calculated as 255 and stored in the RAM 14.

  Further, when the gradation value of the third display pixel 23 adjacent to the right of the second display pixel 22 is 0, the difference in gradation value between the second display pixel 22 and the third display pixel 23 (pixel brightness difference). ) Is 255. When the gradation value of the fourth display pixel 24 adjacent to the right of the third display pixel 23 is 128, the difference in gradation value between the third display pixel 23 and the fourth display pixel 24 (pixel brightness difference). ) Is 127.

  Thus, in the pixel brightness difference calculation process (step S215), the absolute value of the pixel brightness difference, which is the amount of change (difference) in the gradation value of adjacent display pixels on the horizontal line, is calculated, and the pixel for each frame is calculated. The brightness difference information is stored in the RAM 14.

  Next, the image control unit 12 executes a partition process (Step S216) that partitions the displayed display image into a plurality of display areas. In this partitioning process (step S216), as shown in FIG. 5, the image control unit 12 divides, for example, the entire display image into 12 regions (A to L regions 2a to 2l). Note that the number of divisions is not limited to twelve. Further, the positions to be divided in the display image are not limited to equal intervals, and can be divided at unequal intervals.

  Then, the image control unit 12 serves as a pixel lightness difference integration unit, and a difference in gradation values (pixel lightness difference) between adjacent display pixels on the horizontal line in the divided display areas A to L regions 2a to 2l. Pixel brightness difference integration processing (step S221) is performed, and the image control unit 12 further serves as image quality determination data extraction means from among the gradation value differences (pixel brightness differences) between adjacent display pixels. An image quality determination data extraction process (step S223) for extracting image quality determination data is executed.

  The pixel lightness difference integration process (step S221) is a process performed based on the gradation value information of each frame. In this process, pixels on all horizontal lines from the top to the bottom in each display area 2 are processed. The brightness differences are sequentially accumulated, and the sum of the gradation value differences (pixel brightness differences) between adjacent display pixels on the horizontal line constituting the display area 2 is obtained for each display area 2 constituting each frame. This total may be obtained for each display area 2 in a predetermined frame, or may be obtained by averaging for each display area 2 in all frames.

  In the image quality determination data extraction process (step S223), the maximum value is displayed for each display area 2 for each frame from the pixel brightness difference data of each frame stored in the RAM 14 in the pixel brightness difference calculation process (step S215). Extracted as image quality determination data. When there are a plurality of maximum values in the display area 2 of the predetermined frame, one of them is arbitrarily extracted. That is, 32 pieces of image quality determination data are extracted for each of the 12 areas.

  Next, the image control unit 12 designates a display area in which the total pixel brightness difference integrated in the pixel brightness difference integration process (step S221) exceeds a predetermined value from among the divided display areas 2. (Step S226) is executed.

  In the area designation process (step S226), when the total pixel brightness difference is less than the first threshold value, the image control unit 12 designates the level of the display area 2 as 1, and is greater than or equal to the first threshold value and less than the second threshold value. In the case of the above, the level of the display area 2 is designated as 2, and when the second threshold is less than the third threshold, the level of the display area 2 is designated as 3, and when the level is greater than the third threshold, the display Designate the level of area 2 as 4.

  That is, in the area designation process (step S226), the display area 2 is designated in a plurality of levels according to the total pixel brightness difference accumulated in the pixel brightness difference accumulation process (step S221). That is, in the phase adjustment in the phase adjustment device 1, the display area 2 that should be emphasized in order to set the optimum phase of the entire display image is automatically designated. The number of levels and the threshold value can be arbitrarily set.

  Next, the image control unit 12 executes a shift amount determination process (step S301) for determining an optimum phase shift amount value for each display area 2. In this shift amount determination processing (step S301), the maximum one is extracted from the image quality determination data for each frame for each display area 2 stored in the RAM 14, and the phase of the sampling clock corresponding to this maximum one is extracted. Is the optimum phase, and the optimum phase shift value (number of steps) corresponding to this optimum phase is determined.

  Then, the image control unit 12 sets the optimum phase shift amount value for the entire display image based on the optimum phase shift amount value for each display area 2 determined in the shift amount determination process (step S301). Processing (step S305) is executed.

  In this phase optimization process (step S305), the value of the optimum phase shift amount of the display area 2 designated in the area designation process (step S226) is weighted according to the level designated for each display area 2. By averaging, the value of the optimum phase shift amount of the entire display image is set.

  Here, for example, as shown in FIG. 6, the levels of the A region 2a, B region 2b, and E region 2e are designated as 4, the levels of the C region 2c and F region 2f are designated as 3, and the D region 2d, G It is assumed that the level of the area 2g and the H area 2h is designated as 2, and the level of the remaining display areas I area 2i, J area 2j, K area 2k, and L area 2l is designated as 1. Note that the RAM 14 stores the number of steps of the optimum phase (that is, the value of the optimum phase shift amount) for each display area 2 as described above.

  Then, the image control unit 12 sets the weight of the display area 2 (A region 2a, B region 2b, E region 2e) designated as level 4 to 2, and the display area 2 designated as level 3 (C region 2c, The weight (F region 2f) is set to 1, and the optimum phase shift value (number of steps) for each corresponding display area 2 is averaged, and the average value is set as the optimum phase of the entire display image. In this example, the optimal phase step number is set to 10 from the calculation formula of (10 × 2 + 11 × 2 + 9 × 2 + 9 × 1 + 8 × 1) / (2 + 2 + 2 + 1 + 1) for the entire display image.

  Here, the display area 2 of level 1 and level 2 has a small pixel brightness difference (difference between adjacent gradation values) and is not suitable for calculating the optimum value of the phase. The optimum phase is set on the basis of the information in the display area 2 that has a large pixel brightness difference and should be emphasized in the phase adjustment even in the selected area. This is because the difference in gradation value between adjacent pixels (pixel brightness difference) is small in areas with little gradation change, such as natural images, so the pixel brightness difference (image quality) that is the largest in the display area 2 If the optimum phase shift amount is determined by the judgment data), it will not stand out in natural images with small gradation changes, but it will not be able to perform sampling properly when displaying images with large gradation changes. This is because of

  Thus, according to the phase adjustment apparatus 1 according to the present embodiment, the optimum phase of the entire display image is determined based on the optimum phase (value of the optimum phase shift amount) in the portion to be emphasized in the display image. By setting, information for displaying a clear image can be provided to the image forming unit 15 in the entire display image.

  In the above embodiment, the difference in gradation value between adjacent display pixels is calculated as the pixel brightness difference, the pixel brightness difference is integrated for each display area 2, and the display area 2 to be emphasized is designated. However, the pixel brightness difference is not limited to the difference in gradation value between adjacent display pixels, but is obtained as the difference in gradation value between pixels for each predetermined number of intervals, such as one or two. Sometimes. Further, a frame that calculates a difference in gradation values before and after the frame in the same display pixel as a frame brightness difference from information on gradation values for each frame, and integrates this frame brightness difference in all display pixels in the display area 2 The brightness difference integration process may be executed.

  If the digital video signal is not properly sampled from the analog video signal, the video signal data assigned to two adjacent display pixels may be sampled erroneously and the screen may flicker. This flickering appears prominently in areas with large gradation changes, so even with this method, the display area 2 that should be emphasized in phase adjustment is specified, the phase of the entire display image is optimally adjusted, and a clear image is displayed. Information for the image forming unit 15 can be provided.

  Then, the image control unit 12 takes in a change amount (difference) of the gradation value for each frame in each display pixel in the display area 2 as a frame brightness integration means, and takes in all the display area 2 as a frame brightness difference. A frame lightness difference integration process for integrating the display pixel gradation value difference (frame lightness difference) for each display area 2 is executed, and the image control unit 12 serves as an area designating unit to calculate the total frame lightness difference. By executing the area specification process that specifies the display area 2 that exceeds the predetermined value, in the phase optimization process, based on the specified value of the optimum phase shift amount of the display area 2 that should be emphasized, as in the above embodiment. Thus, the value of the optimum phase shift amount of the entire display image can be set, and information for displaying a clean image in the entire display image can be provided to the image forming unit 15.

  Furthermore, in the area designation process, the display area 2 is designated by dividing it into a plurality of levels according to the total frame brightness difference, and the value of the optimum phase shift amount of the designated display area 2 to be emphasized is weighted according to the level. It is also possible to set the value of the optimum phase shift amount of the entire display image by executing a phase optimization process for averaging. This is preferable because the optimum phase can be set by dividing the display area 2 to be emphasized into a plurality of levels and reflecting it in the entire display image.

  Further, as a modification of the phase adjustment device 1, the image control unit 12 executes character recognition processing for recognizing characters in the display area 2 partitioned by the partition processing as character recognition means, and is recognized by this character recognition processing. A configuration can be adopted in which the image control unit 12 executes area designation processing for designating the display area 2 in which the number of characters exceeds a predetermined value as the area designation means. If such a phase adjustment device 1 is employed, in the display area 2 where many characters are described, the pixel brightness difference between adjacent display pixels is usually large, so the display area 2 to be emphasized is appropriately designated. be able to. Thus, according to the present modification, in the phase optimization process, the optimum phase shift amount value of the entire display image is set based on the optimum phase shift amount value of the display area 2 designated in the area designation process. Thus, the same effect as described above can be obtained.

  Furthermore, when this modification is adopted, area designation processing is performed for designating display area 2 in multiple levels according to the number of characters recognized in character recognition processing, and area designation processing is performed in phase optimization processing. By setting the optimal phase shift amount value for display area 2 specified in step 1 by weighting and averaging according to the level, the optimal phase shift amount value for the entire display image is set, and the same effect as above is obtained. Obtainable.

  The phase adjusting device 1 can be mounted on various image display devices such as a projector and a display. Hereinafter, an example of mounting on a projector as an image display device will be described with reference to FIGS.

  As shown in FIG. 7, the projector 100 has a substantially rectangular parallelepiped shape, and includes a lens cover 109 that covers the projection port on the side of the front panel 102 that is a side plate in front of the projector housing. Further, although not shown, an Ir receiver for receiving a control signal from the remote controller is provided.

  The top panel 101 of the housing is provided with a key / indicator section 37. The key / indicator section 37 switches a power switch key, a power indicator for notifying power on / off, and switching on / off of projection. Keys and indicators such as an overheat indicator for notifying when a projection switch key, a light source unit, a display element, a control circuit, etc. are overheated are arranged.

  In addition, on the back of the chassis, various terminals 120 such as an input / output connector section and a power adapter plug are provided on a back panel (not shown) for providing a USB terminal, a D-SUB terminal for inputting image signals, an S terminal, an RCA terminal, and the like. It has been. Note that the side plate of the housing is formed with an intake hole for taking in cooling air and an exhaust hole as an outlet for cooling air exhausted after cooling the inside.

  Next, the function of the projector 100 will be described using the functional block diagram of FIG. The projector 100 includes a CPU 38, an image conversion unit 10, an image forming unit 15, and the like. The phase adjustment device 1 includes an image conversion unit 10, a video RAM 13, a ROM 16, a RAM 14, and the like, and is configured to operate based on a command signal from the CPU 38. The CPU 38 is a display device control unit that controls the operation of each circuit in the projector 100, and transmits a command signal for causing the image forming unit 15 to output image information from the image control unit 12, and adjusts the phase. In the mode, a command signal for phase adjustment operation is transmitted to the image control unit 12. The ROM 16 stores various operation programs in a fixed manner, and the RAM 14 is a storage means used as a work memory.

  The digital image signal input from the input / output connector unit 30 is converted so as to be unified into an image signal of a predetermined format suitable for display by the image conversion unit 10 via the input / output interface 33 and the system bus (SB). . The analog image signal input from the input / output connector unit 30 is directly sent to the AD converter 11 of the image conversion unit 10 via the input / output interface 33, and is converted into an image signal of a predetermined format suitable for display. . Then, the image signal converted into the image signal of a predetermined format by the image conversion unit 10 is expanded and stored in the video RAM 13, and then a video signal is generated from the stored contents of the video RAM 13, and spatially at an appropriate frame rate. An image forming unit (display element) 15 that is a light modulation element (SOM) is driven. Thereby, the light bundle emitted from the light source unit 60 is condensed on the image forming unit 15 via the light source side optical system, thereby forming an optical image with the reflected light of the image forming unit 15, and the projection side optical system being Thus, an image can be projected and displayed on a screen (not shown). The movable lens group 97 of the projection side optical system is driven by the lens motor 45 for zoom adjustment and focus adjustment.

  Here, the information sent to the image forming unit 15 is information based on the video signal sampled by the sampling clock having the phase optimized by the phase adjusting device 1. That is, in the projector 100, when the user executes the phase adjustment operation, the phase of the entire display image is optimized and the phase of the sampling clock is set by the function of the phase adjustment device 1 described above. .

  The image compression / decompression unit 31 performs a recording process in which the luminance signal and the color difference signal of the image signal are data-compressed by a process such as ADCT and Huffman coding, and sequentially written in a memory card 32 that is a detachable recording medium. Further, the image compression / decompression unit 31 reads out the image data recorded on the memory card 32 in the reproduction mode, decompresses individual image data constituting a series of moving images in units of one frame, and converts the image data into the image conversion unit 10. And a process for enabling display of a moving image or the like based on the image data stored in the memory card 32.

  Then, an operation signal of a key / indicator unit 37 composed of a main key and an indicator provided on the top panel 101 of the casing is directly sent to the CPU 38, and a key operation signal from the remote controller is sent to the Ir receiving unit 35. , And the code signal demodulated by the Ir processing unit 36 is output to the CPU 38.

  Further, a light source unit drive circuit 41 is connected to the CPU 38, and the CPU 38 and the light source unit drive circuit 41 are configured so that light sources in the red, green, and blue bands required at the time of image generation are emitted from the light source unit 60. Furthermore, it functions as a light source control means for controlling the light source unit 60.

  Further, the CPU 38 causes the cooling fan drive control circuit 43 to perform temperature detection using a plurality of temperature sensors provided in the light source unit 60 and the like, and individually controls the rotational speeds of the plurality of cooling fans from the result of the temperature detection. Further, the CPU 38 and the cooling fan drive control circuit 43 maintain the rotation of the cooling fan even after the power of the projector main body is turned off by a timer or the like, or the power of the projector main body is turned off depending on the result of temperature detection by the temperature sensor. Also controls.

  As described above, if the phase adjustment device 1 is mounted on the projector 100 that projects an image on the screen, the CPU 38 can control the phase adjustment device 1 to adjust the phase. A clear and flicker-free and clear color image can be projected on the screen.

  And this invention is not limited to the above Example, A change and improvement are possible freely in the range which does not deviate from the summary of invention.

1 Phase adjuster
2 Display area 2a ~ 2l A ~ L area
9 Video signal source
10 Image converter 11 AD converter
12 Image controller 13 Video RAM
14 RAM 15 Image forming unit
16 ROM 21 First display pixel
22 Second display pixel 23 Third display pixel
24 Fourth display pixel 30 Input / output connector
31 Image compression / decompression unit 32 Memory card
33 I / O interface 35 Ir receiver
36 Ir processing section 37 Key / indicator section
38 CPU 41 Light source unit drive circuit
43 Cooling fan drive control circuit 45 Lens motor
60 Light source unit 97 Movable lens group
100 Projector 101 Top panel
102 Front panel 109 Lens cover
120 Various terminals

Claims (15)

Sampling clock generating means for generating a sampling clock;
AD conversion means for sampling an input analog video signal with the sampling clock and converting it into a digital video signal;
Phase shift means for shifting the phase of the sampling clock;
Partition means for partitioning a display image to be displayed based on the digital video signal output from the AD conversion means into a plurality of display areas;
Shift amount determining means for determining the value of the optimum phase shift amount for each display area;
Based on the value of the optimum phase shift amount for each display area determined by the shift amount determining means, phase optimization means for setting the value of the optimum phase shift amount for the entire display image;
A phase adjustment apparatus comprising: Pixel brightness difference integration means for integrating the pixel brightness difference between adjacent display pixels on a horizontal line in the display image for each display area;
Area designation means for designating a display area where the total pixel brightness difference accumulated by the pixel brightness difference accumulation means exceeds a predetermined value,
The said phase optimization means sets the value of the optimal phase shift amount of the whole display image based on the value of the optimal phase shift amount of the display area designated by the said area designation means. The phase adjustment device described. The area designating unit designates a display area divided into a plurality of levels according to the total pixel brightness difference accumulated by the pixel brightness difference accumulation unit,
The phase optimizing unit averages the value of the optimum phase shift amount of the display area designated by the area designating unit with a weight according to the level, thereby averaging the value of the optimum phase shift amount of the entire display image The phase adjustment apparatus according to claim 2, wherein: The amount of change in gradation value for each frame in each display pixel within the display area partitioned by the partitioning means is taken in, and the frame brightness difference of all display pixels in each display area is integrated for each display area Frame lightness difference integration means to perform,
Area designation means for designating a display area in which the total frame lightness difference accumulated by the frame lightness difference accumulation means exceeds a predetermined value,
The said phase optimization means sets the value of the optimal phase shift amount of the whole display image based on the value of the optimal phase shift amount of the display area designated by the said area designation means. The phase adjustment device described. The area designating unit designates a display area divided into a plurality of levels according to the total frame lightness difference accumulated by the frame lightness difference accumulating unit,
The phase optimizing unit averages the value of the optimum phase shift amount of the display area designated by the area designating unit with a weight according to the level, thereby averaging the value of the optimum phase shift amount of the entire display image The phase adjustment device according to claim 4, wherein: Character recognition means for recognizing characters in the display area partitioned by the partition means;
Area designation means for designating a display area in which the number of characters recognized by the character recognition means exceeds a predetermined value,
The said phase optimization means sets the value of the optimal phase shift amount of the whole display image based on the value of the optimal phase shift amount of the display area designated by the said area designation means. The phase adjustment device described. The area designation means designates a display area divided into a plurality of levels according to the number of characters recognized by the character recognition means,
The phase optimizing unit averages the value of the optimum phase shift amount of the display area designated by the area designating unit with a weight according to the level, thereby averaging the value of the optimum phase shift amount of the entire display image The phase adjustment apparatus according to claim 6, wherein: Sampling clock generation processing for generating a sampling clock;
A / D conversion processing for sampling an input analog video signal with the sampling clock and converting it to a digital video signal;
A phase shift process for shifting the phase of the sampling clock;
Partition processing for partitioning a display image to be displayed based on the digital video signal output in the AD conversion processing into a plurality of display areas;
Shift amount determination processing for determining the value of the optimum phase shift amount for each display area;
Based on the value of the optimal phase shift amount for each display area determined in the shift amount determination process, a phase optimization process for setting the value of the optimal phase shift amount of the entire display image;
The phase adjustment method characterized by performing. A pixel brightness difference integration process for integrating the pixel brightness difference between adjacent display pixels of a horizontal line in the display image for each display area;
An area designating process for designating a display area in which the total pixel brightness difference accumulated in the pixel brightness difference integrating process exceeds a predetermined value;
9. The optimum phase shift amount value for the entire display image is set based on the optimum phase shift amount value of the display area designated in the area designation processing in the phase optimization processing. The phase adjustment method described. In the area designation process, according to the total pixel lightness difference accumulated in the pixel lightness difference accumulation process, the display area is designated in a plurality of levels,
In the phase optimization process, the value of the optimum phase shift amount of the display area designated in the area designation process is weighted according to the level and averaged to obtain the value of the optimum phase shift amount of the entire display image The phase adjustment method according to claim 9, wherein: The amount of change in gradation value for each frame in each display pixel within the display area partitioned by the partition processing is taken in, and the frame brightness differences of all display pixels in each display area are integrated for each display area Frame brightness difference integration processing,
An area designating process for designating a display area in which the total frame lightness difference accumulated in the frame lightness difference accumulation process exceeds a predetermined value;
9. The optimum phase shift amount value for the entire display image is set based on the optimum phase shift amount value of the display area designated in the area designation processing in the phase optimization processing. The phase adjustment method described. In the area designation process, according to the total frame lightness difference accumulated in the frame lightness difference accumulation process, the display area is designated in a plurality of levels,
In the phase optimization process, the value of the optimum phase shift amount of the display area designated in the area designation process is weighted according to the level and averaged to obtain the value of the optimum phase shift amount of the entire display image The phase adjustment method according to claim 11, wherein: Character recognition processing for recognizing characters in the display area partitioned by the partition processing;
Performing an area designation process for designating a display area in which the number of characters recognized in the character recognition process exceeds a predetermined value;
9. The optimum phase shift amount value for the entire display image is set based on the optimum phase shift amount value of the display area designated in the area designation processing in the phase optimization processing. The phase adjustment method described. In the area designation process, according to the number of characters recognized in the character recognition process, the display area is designated in a plurality of levels,
In the phase optimization process, the value of the optimum phase shift amount of the display area designated in the area designation process is weighted according to the level and averaged to obtain the value of the optimum phase shift amount of the entire display image The phase adjustment method according to claim 13, wherein: A phase adjustment device;
Display device control means,
The phase adjustment device is the phase adjustment device according to any one of claims 1 to 7,
The display device control means controls the phase adjustment device to adjust the phase.

Images