JP2006234873A - Projector, and display mode discrimination method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of shortening the period needed for discriminating the display mode of image signal, and to provide a display mode discrimination method therefor. <P>SOLUTION: The projector comprises a tracking setting means for temporarily selecting one display mode from a plurality of candidates and setting tracking, based on signal information of the display mode stored in a storing section; a resolution-deriving means in which the image signal is sampled based on the tracking setting and in which the resolution of an image expressed by the image signal is derived, based on the sampling result; an error calculating means for calculating a difference between the resolution derived by the resolution deriving means, by reading the signal information stored in the storing section for each of the candidates and the resolution, based on the signal information; and a mode-determining means for determining the display mode of the image signal, based on the difference calculated by the error calculation means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projector that receives an image signal and projects an optical image corresponding to the image signal, and a display mode determination method thereof.

  A projector that inputs an image signal, projects an optical image according to the image signal, and displays the image on a screen or the like is input to display an appropriate image according to the image signal in various display modes. The display mode of the image signal can be discriminated from the obtained image signal (for example, Patent Document 1).

  FIG. 1 is a block diagram showing a schematic configuration of a conventional projector, and FIG. 2 is an explanatory diagram showing a mode table stored in the projector.

  As shown in FIG. 1, the projector 1 receives an image signal from an external image supply device PC, and can project an optical image corresponding to the image signal onto a screen SC. 11, a PLL (Phase Locked Loop) circuit 12, an image processing unit 13, an image memory 14, and an image projection unit 15. The control unit 10 is connected to each of the units 11 to 13 and comprehensively controls the operation of the projector 1 according to a control program stored in the storage unit 11. The image signal input to the projector 1 includes a signal representing image information (for example, an RGB signal), a horizontal synchronization signal Hsync that defines the scanning timing of the signal, and a vertical synchronization signal Vsync. The control unit 10 can determine the display mode of the image signal with reference to the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync, and the like.

  The storage unit 11 is configured by a memory such as a flash ROM (Read Only Memory), and stores the control program and is used for storing various setting values. Further, the storage unit 11 stores a mode table 11a as shown in FIG. The mode table 11a stores signal information related to various display modes that the projector 1 can handle. As signal information, for example, horizontal frequency (frequency of the horizontal synchronization signal Hsync), horizontal resolution, vertical resolution, tracking value (number of clocks in one horizontal scanning period), number of vertical lines (horizontal scanning lines in one vertical scanning period) Number) etc. The control unit 10 reads out the signal information of the specified display mode from the storage unit 11 and controls the PLL circuit 12 and the image processing unit 13 based on this signal information.

  The PLL circuit 12 generates a clock signal for sampling the image signal (RGB signal) and outputs the clock signal to the image processing unit 13. Specifically, the PLL circuit 12 inputs the horizontal synchronization signal Hsync included in the image signal from the image supply device PC, and inputs a control signal corresponding to the tracking value of the specified display mode from the control unit 10. A clock signal for generating a number of clocks corresponding to the tracking value in one horizontal scanning period is output in synchronization with the horizontal synchronizing signal Hsync.

  The image processing unit 13 receives an image signal (RGB signal) from the image supply device PC, and generates image data by sampling based on the clock signal from the PLL circuit 12. Further, the image processing unit 13 temporarily stores the generated image data in the image memory 14, performs various image processing, and outputs the processed image data to the image projection unit 15.

  The image projection unit 15 includes a light source, a light modulation device, a projection lens (none of which are shown), and the light emitted from the light source is modulated by the light modulation device in accordance with the sampled image data and projected. Projected from the lens onto the screen SC or the like. Thereby, an image corresponding to the image signal is displayed on the screen SC.

  Next, a display mode determination procedure in a conventional projector will be described with reference to the drawings. FIG. 4 is a flowchart for explaining the operation when determining the display mode of the image signal. When the image signal is input, the projector 1 determines the display mode of the image signal based on the flow.

  As shown in FIG. 4, in step S310, a first mode determination is performed. Specifically, the control unit 10 detects the horizontal frequency of the image signal, the number of vertical lines, the polarity of each synchronization signal, and the like based on the horizontal synchronization signal Hsync and the vertical synchronization signal Vsync included in the input signal. The control unit 10 refers to the mode table 11a (see FIG. 2) stored in the storage unit 11 and selects a display mode having signal information that matches or approximates the detection result. Many display modes are uniquely specified by the first mode discrimination. However, in some display modes, a plurality of display modes remain as candidates, and further discrimination processing (second mode discrimination) is performed. Need to go and identify one. For example, among the display modes shown in the mode table 11a of FIG. 2, MAC_12c and MAC_12ce have the same horizontal frequency, number of vertical lines, polarity of each synchronization signal (the polarity is not shown), etc. Only one mode discrimination cannot be specified as either one.

  Therefore, in step S320, it is determined whether the second mode determination is necessary. If one display mode has already been specified in step S310 (first mode determination) and no further determination is necessary, the process ends. If there are a plurality of candidates and the second mode determination is required, step S310 is performed. The process proceeds to S330.

  In step S330, the control unit 10 provisionally selects one display mode from a plurality of candidates, reads the tracking value of the display mode from the mode table 11a, and sets it in the PLL circuit 12. As a result, the PLL circuit 12 outputs a clock signal corresponding to the set tracking value to the image processing unit 13.

  The controller 10 waits for a predetermined time (for example, 100 ms) until the PLL circuit 12 is stabilized in step S340, and then determines whether or not the PLL circuit 12 is locked in step S350. If the PLL circuit 12 is locked, the process proceeds to step S360. If not, the process proceeds to step S370, where it is determined that the image signal cannot be handled, and the process ends.

  When the process proceeds to step S360, the control unit 10 derives the resolution of the image represented by the image signal. Specifically, the image processing unit 13 samples an image signal at a period set for tracking, and based on the sampled image data, an HBI (Horizontal Blanking Interval: horizontal blanking interval) that is a period in which image information is not included. Period) is detected and output to the control unit 10. The control unit 10 calculates the horizontal resolution from the horizontal frequency detected in step S310 (first mode determination) and the HBI.

  In step S380, the control unit 10 reads out the horizontal resolution of the provisionally selected display mode from the mode table 11a, and derives a difference from the resolution derived in step S360.

  In step S390, it is determined whether or not steps S330 to S380 have been performed for all candidates. If there are unexecuted candidates, the process returns to step S330, one candidate is selected from the remaining candidates, the above flow is repeated, and the above processing (tracking setting to difference calculation) is completed for all candidates. Then, the process proceeds to step S400.

  In step S400, the smallest difference between the resolution derived in step S360 and the resolution on the mode table 11a for each candidate is determined to be the display mode of the image signal, and the mode determination process ends.

  Here, the mode determination operation according to the above flow will be described by taking as an example a case where an image signal whose display mode is MAC_12ce is input.

  First, in step S310, as a result of performing the first mode determination, it is determined that the display mode of the image signal is either MAC_12c or MAC_12ce. In step S320, since there are a plurality (two) of display mode candidates, the process proceeds to step S330.

  In step S330, one of the candidate display modes (here, MAC_12c) is provisionally selected for MAC_12c and tracking setting is performed. According to the mode table 11a, since the tracking value of MAC_12c is 640, the PLL circuit 12 generates a clock signal for generating 640 clocks in one horizontal scanning period. Thereafter, after waiting for 100 ms in step S340 and stabilizing the PLL circuit 12, if the PLL circuit 12 is locked in step S350, the process proceeds to step S360.

  In step S360, the horizontal resolution is calculated after sampling the image signal with a tracking value of 640 to detect HBI (specifically, the number of clocks in the HBI). The actual display mode MAC_12ce has a tracking value of 704, a horizontal resolution of 560, and the ratio of HBI in one horizontal scanning period is (704-560) / 704. When sampling is performed with the tracking value 640, a clock of approximately 640 × (704-560) / 704≈131 is detected as the HBI. The control unit 10 calculates 640−131 = 509 as the horizontal resolution from the tracking value (640) and the HBI (number of clocks: 131).

  In step S380, the difference (3) is calculated from the derived horizontal resolution (509) and the horizontal resolution (512) on the mode table 11a of the temporarily selected MAC_12c.

  In step S390, since resolution derivation has not been performed for another candidate (MAC_12ce), the process returns to step S330, and in step S330, MAC_12ce is temporarily selected and tracking setting is performed. According to the mode table, since the tracking value of MAC_12ce is 704, the PLL circuit 12 generates a clock signal that generates a clock of 704 in one horizontal scanning period. Thereafter, after waiting for 100 ms in step S340 and stabilizing the PLL circuit 12, if the PLL circuit 12 is locked in step S350, the process proceeds to step S360.

  In step S360, when the image signal is sampled with the set tracking value 704, a clock of approximately 704 to 560 = 144 is detected as the HBI. The control unit 10 calculates 704-144 = 560 as the horizontal resolution from the tracking value (704) and the HBI (number of clocks: 144).

  In step S380, the difference (0) is calculated from the derived horizontal resolution (560) and the horizontal resolution (560) on the MAC_12ce mode table 11a.

  In step S390, since resolution derivation has been completed for all candidates, the process proceeds to step S400, and in step S400, the two differences (3 and 0) calculated in step S380 are compared, and the value with the smallest difference ( 0) is determined as the display mode of the image signal (MAC_12ce). As described above, it is possible to determine a display mode that is difficult to specify only by the first mode determination.

WO98 / 20476

  However, in the mode discrimination according to the above flow, it is necessary to repeat the operation (steps S330 to S380) including the standby time (for example, 100 ms) as many times as the number of candidates, so that the discrimination processing takes time. Had.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a projector capable of reducing the time required to determine the display mode of an image signal and a display mode determination method thereof.

  The projector of the present invention is a projector that determines a display mode of an input image signal, samples the image signal according to the determined display mode, and projects an optical image according to the image signal. A storage unit storing signal information for each display mode, and a first mode determination unit that narrows down the display mode of the image signal to one or a plurality of candidates based on a synchronization signal included in the image signal; A second mode discriminating unit for specifying one display mode from the plurality of candidates when the first mode discriminating unit narrows down to a plurality of candidates. The means for temporarily selecting one display mode from the plurality of candidates and setting tracking based on the signal information of the display mode stored in the storage unit. Sampling means, sampling the image signal based on the tracking setting, deriving the resolution of the image represented by the image signal based on the sampling result, and for each candidate, the storage unit Error calculation means for calculating a difference between the resolution based on the signal information stored in the resolution and the resolution derived by the resolution deriving means, and the image signal based on the difference calculated by the error calculation means. And a mode determining means for determining the display mode.

  According to this projector, the tracking setting is performed based on the provisionally selected display mode signal information, the image signal is sampled with the tracking setting to derive the resolution of the image, and the resolution is stored in the storage unit. The display mode is determined based on the difference from the resolution based on the signal information of each candidate. In other words, since the display mode is determined by comparing the resolution derived by one tracking setting with the resolutions of a plurality of candidates, the tracking setting and this are compared with the case where the tracking setting is performed in a plurality of display modes. It is possible to reduce the number of times of waiting for time. As a result, the time required for mode discrimination can be shortened.

  In this projector, the error calculation unit converts the resolution of each candidate stored as signal information in the storage unit into a resolution for the tracking value of the display mode provisionally selected by the tracking setting unit. It is desirable to calculate the difference between the value and the resolution derived by the resolution deriving means.

    The display mode determination method of the present invention includes a storage unit that stores signal information for each of a plurality of display modes, determines a display mode of an input image signal from the plurality of display modes, and determines the determined A method for determining a display mode of a projector that samples an image signal according to a display mode and projects an optical image according to the image signal, wherein the image signal is based on a synchronization signal included in the image signal. When the display mode is narrowed down to a plurality of candidates by the first mode determination step for narrowing the display mode to one or a plurality of candidates and the first mode determination step, one display mode is selected from the plurality of candidates. A second mode determining step for specifying, wherein the second mode determining step temporarily selects one display mode from the plurality of candidates, and is stored in the storage unit A tracking setting step for setting tracking based on the signal information of the display mode, and a resolution for sampling the image signal based on the tracking setting and deriving the resolution of the image represented by the image signal based on the sampling result An error calculation for reading out the signal information stored in the storage unit for each candidate and calculating the difference between the resolution derived by the resolution deriving step and the resolution based on the signal information for each candidate And a mode determining step of determining a display mode of the image signal based on the difference calculated by the error calculating means.

  According to this display mode determination method, tracking setting is performed based on provisionally selected display mode signal information, the image signal is sampled with the tracking setting to derive the resolution of the image, the resolution, and the storage unit The display mode is determined based on the difference from the resolution based on the signal information of each candidate stored in the screen. In other words, since the display mode is determined by comparing the resolution derived by one tracking setting with the resolutions of a plurality of candidates, the tracking setting and this are compared with the case where the tracking setting is performed in a plurality of display modes. It is possible to reduce the number of times of waiting for time. As a result, the time required for mode discrimination can be shortened.

Hereinafter, a projector according to an embodiment of the present invention will be described with reference to the drawings. Since the projector according to the present embodiment has the same configuration as that of the conventional projector (see FIG. 1), the description of the schematic configuration is omitted, and the mode of the image signal is determined with reference to FIG. Will be described.
FIG. 3 is a flowchart for explaining the operation when determining the display mode of the image signal in the projector of this embodiment. When the image signal is input, the projector 1 determines the display mode of the image signal based on the flow.
As shown in FIG. 3, in step S110, a first mode determination is performed. Specifically, the control unit 10 detects the horizontal frequency of the image signal, the number of vertical lines, the polarity of each synchronization signal, and the like based on the horizontal synchronization signal Hsync and the vertical synchronization signal Vsync included in the input image signal. The control unit 10 refers to the mode table 11a (see FIG. 2) stored in the storage unit 11 and selects a display mode having signal information that matches or approximates the detection result.

  In step S120, it is determined whether the second mode determination is necessary. If one display mode has already been specified in the first mode determination and no further determination is necessary, the process ends. If there are a plurality of candidates and the second mode determination is required, the process proceeds to step S130. .

  In step S130, the control unit 10 provisionally selects one display mode from a plurality of candidates, reads the tracking value of the display mode from the mode table 11a, and sets it in the PLL circuit 12. As a result, the PLL circuit 12 outputs a clock signal corresponding to the set tracking value to the image processing unit 13.

  The controller 10 waits for a predetermined time (for example, 100 ms) until the PLL circuit 12 is stabilized in step S140, and then determines whether or not the PLL circuit 12 is locked in step S150. If the PLL circuit 12 is locked, the process proceeds to step S160. If the PLL circuit 12 is not locked, the process proceeds to step S170 to determine that the image signal cannot be handled, and the process ends.

  When the process proceeds to step S160, the control unit 10 derives the resolution of the image represented by the image signal. Specifically, the image processing unit 13 samples an image signal at a period set for tracking, and based on the sampled image data, an HBI (Horizontal Blanking Interval: horizontal blanking interval) that is a period in which image information is not included. Period) is detected and output to the control unit 10. The control unit 10 calculates the horizontal resolution from the horizontal frequency detected in step S110 and the HBI.

  In step S180, the control unit 10 reads the horizontal resolution of the display mode provisionally selected in step S130 from the mode table 11a, and derives the difference from the resolution derived in step S160.

  In step S190, the control unit 10 reads out other candidate horizontal resolutions from the mode table 11a, converts the horizontal resolution into a resolution for the tracking value of the provisionally selected display mode, and the step S160. The difference from the derived resolution is derived.

  In step S200, it is determined whether step S190 has been performed for all candidates. If there are unexecuted candidates, the process returns to step S190, and one candidate is selected from the remaining candidates and the above flow is repeated. If all the candidates have been processed, the process proceeds to step S210.

  In step S210, the one having the smallest difference between the resolution derived in step S160 and the resolution on each candidate mode table 11a is determined to be the display mode of the image signal, and the mode determination process is terminated. .

  Here, the mode determination operation according to the above flow will be described by taking as an example a case where an image signal whose display mode is MAC_12ce is input.

  First, in step S110, as a result of performing the first mode determination, it is determined that the display mode of the image signal is either MAC_12c or MAC_12ce. In step S120, since there are a plurality (two) of display mode candidates, the process proceeds to step S130.

  In step S130, tracking setting is performed by temporarily selecting one of the candidate display modes (here, MAC_12c). According to the mode table 11a, since the tracking value of MAC_12c is 640, the PLL circuit 12 generates a clock signal for generating 640 clocks in one horizontal scanning period. After that, after waiting for 100 ms in step S140 and the PLL circuit 12 is stabilized, if the PLL circuit 12 is locked in step S150, the process proceeds to step S160.

  In step S160, after sampling the image signal with the tracking value 640 to detect HBI (specifically, the number of clocks in the HBI), the horizontal resolution is calculated. The actual display mode MAC_12ce has a tracking value of 704, a horizontal resolution of 560, and the ratio of HBI in one horizontal scanning period is (704-560) / 704. When sampling is performed with the tracking value 640, a clock of approximately 640 × (704-560) / 704≈131 is detected as the HBI. The control unit 10 calculates 640−131 = 509 as the horizontal resolution from the tracking value (640) and the HBI (number of clocks: 131).

  In step S180, the difference (3) is calculated from the derived horizontal resolution (509) and the horizontal resolution (512) on the mode table 11a of the temporarily selected MAC_12c.

  In step S190, the difference between the resolution on the other candidate mode table 11a converted to the resolution for the display mode tracking value selected in step S130 and the resolution derived in step S160 is calculated. That is, the tracking value and horizontal resolution on the mode table 11a of the other candidates (MAC_12ce) are 704 and 560, respectively, and the horizontal resolution (560) corresponding to the tracking value (704) is selected in the display mode (step S130). When converted into the resolution for the tracking value (640) of MAC_12c), 560 × 640 / 704≈509 is obtained. As a result, 0 is derived as the difference between the converted value (509) and the resolution (509) derived in step S160.

  In step S200, since the difference calculation is completed for the two candidates, the process proceeds to step S210. In step S210, the two differences (3 and 0) calculated in steps S180 and S190 are compared, and the difference is the smallest. The display mode (MAC_12ce) that becomes the value (0) is determined as the display mode of the image signal.

As described above, according to the projector 1 and its display mode determination method of the present embodiment, the following effects can be obtained.
According to the projector 1 and the display mode determination method of the present embodiment, the display mode is determined by comparing the resolution derived by one tracking setting with the resolutions of a plurality of candidates. As compared with the case where the tracking setting is performed at, it is possible to reduce the number of times of the tracking setting and the time waiting (100 ms) associated therewith. As a result, the time required for mode discrimination can be shortened.

As described above, in the present embodiment, the control unit 10 corresponds to a first mode determination unit that narrows down the display mode of the image signal to one or a plurality of candidates based on the synchronization signal included in the image signal. .
Further, the control unit 10 uses, for each candidate, an error calculation unit that calculates a difference between the resolution based on the signal information stored in the storage unit and the resolution derived by the resolution deriving unit, and the error calculation unit. Based on the calculated difference, it corresponds to mode determining means for determining the display mode of the image signal, and the control unit 10 and the PLL circuit 12 tentatively select one display mode from the plurality of candidates, This corresponds to tracking setting means for setting tracking based on signal information of the display mode stored in the storage unit. Furthermore, the image processing unit 13 and the control unit 10 correspond to a resolution deriving unit that samples the image signal based on the tracking setting and derives the resolution of the image represented by the image signal based on the sampling result. Therefore, the control unit 10, the PLL circuit 12, and the image processing unit 13 correspond to a second mode determination unit.

(Modification)
In addition, you may change embodiment of this invention as follows.
When the tracking values and horizontal resolutions of a plurality of candidate display modes are the same and the vertical resolutions are different, VBI (Vertical Blanking Interval: vertical blanking interval) is detected based on the sampled image data, The vertical resolution may be calculated from the number of vertical lines detected in step S110 (first mode discrimination) and the VBI, and compared with the vertical resolution of the mode table 11a.

1 is a block diagram illustrating a schematic configuration of a projector according to a related art and an embodiment of the present invention. Explanatory drawing which shows the mode table which a projector memorize | stores. 6 is a flowchart for explaining an operation when determining a display mode of an image signal in the projector according to the embodiment. 9 is a flowchart for explaining an operation when determining a display mode of an image signal in a conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Control part, 11 ... Memory | storage part, 11a ... Mode table, 12 ... PLL circuit, 13 ... Image processing part, 14 ... Image memory, 15 ... Image projection part.

Claims (3)

A projector that determines a display mode of an input image signal, samples the image signal according to the determined display mode, and projects an optical image according to the image signal;
A storage unit storing signal information for each of a plurality of display modes;
First mode discrimination means for narrowing down the display mode of the image signal to one or a plurality of candidates based on a synchronization signal included in the image signal;
A second mode discriminating unit for specifying one display mode from the plurality of candidates when the first mode discriminating unit narrows down to a plurality of candidates;
And the second mode discriminating means comprises:
A tracking setting means for temporarily selecting one display mode from the plurality of candidates and setting tracking based on signal information of the display mode stored in the storage unit;
Sampling the image signal based on the tracking setting, and deriving a resolution of an image represented by the image signal based on the sampling result;
For each of the candidates, an error calculation unit that calculates a difference between the resolution based on the signal information stored in the storage unit and the resolution derived by the resolution deriving unit;
Mode determining means for determining a display mode of the image signal based on the difference calculated by the error calculating means;
A projector comprising:   2. The projector according to claim 1, wherein the error calculation unit is a display mode tracking value temporarily selected by the tracking setting unit for the resolution of each candidate stored as signal information in the storage unit. A projector that calculates a difference between a value converted into a resolution with respect to a resolution derived by the resolution deriving means. A storage unit storing signal information for each of a plurality of display modes; determining a display mode of an input image signal from the plurality of display modes; and determining the image signal according to the determined display mode. A method for determining a display mode of a projector that samples and projects an optical image according to the image signal,
A first mode determination step of narrowing the display mode of the image signal to one or a plurality of candidates based on a synchronization signal included in the image signal;
A second mode determining step for specifying one display mode from the plurality of candidates when the first mode determining step narrows down to a plurality of candidates;
And the second mode discrimination step includes
A tracking setting step of tentatively selecting one display mode from the plurality of candidates and setting tracking based on signal information of the display mode stored in the storage unit;
Sampling the image signal based on the tracking setting, and deriving a resolution of an image represented by the image signal based on the sampling result; and
For each candidate, read out the signal information stored in the storage unit, and calculate the difference between the resolution derived by the resolution deriving step and the resolution based on the signal information,
A mode determination step for determining a display mode of the image signal based on the difference calculated by the error calculation means;
A display mode discrimination method characterized by comprising:

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