JP2005031572A - Picture quality correction system for projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct the picture quality of a projector scrupulouly. <P>SOLUTION: The picture quality correction system 1 has a 1st optical sensor 2 and, for example, a plurality of 2nd optical sensors 18 to 23. The 1st optical sensor 2 is an optical sensor which measures ambient light of a projector main body and provided on the flank, top surface, etc., of the main body. The 2nd sensors are optical sensors which measure the light of a screen 17 for projection and plurally provided in the circumference of a projection video plane. The 1st optical sensor 2 measures the lightness (1st measured value) of the ambient light of the main body and the 2nd optical sensors 18 to 23 find, for example, the mean value (2nd measured value) of detected values of the quantity of light projected on the projection screen; and the mean value of, for example, the 1st measured value and 2nd measured value is found by taking the 1st measured value and 2nd measured value into consideration and when the mean value is smaller than a certain threshold A, it is judged that it is dark in the periphery, thereby preferentially making picture quality corrections in next order as a contrast-priority mode. When it is judged that it is light in the periphery, picture quality corrections are made in a brightness-priority mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image quality correction technique, and more particularly to an image quality correction technique for effectively correcting the image quality of a video by a DLP projector or a liquid crystal projector.

As an apparatus having an image quality correction function for correcting the image quality of the image projected by the liquid crystal projector, as shown in FIG. 8, a light detection sensor 32 for detecting the brightness and color tone around the liquid crystal projector 31 and the image projection surface 38, and The video signal 33a and 33b supplied from the video processing circuit and the liquid crystal panel 35 to the liquid crystal panel 35 are adjusted based on the detected brightness and color tone of the periphery and the periphery of the video projection surface, and the lamp controller 37 controls the lamp 36. An apparatus including a control unit (CPU) 33 that also adjusts the amount of light emission is disclosed (for example, see Patent Document 1).
JP 2002-311503 A

The above technique automatically corrects the contrast, brightness, hue component, etc. of the video signal 33a supplied to the liquid crystal panel 35 based on the brightness and hue of the surrounding environment, and further, the lamp 36 incident on the liquid crystal panel 33. The amount of change in correction is determined by the contrast, brightness, hue, and brightness of the lamp (power control), and the dynamic range of the correction variable range cannot be widened. There was a problem that it was difficult to correct the image quality.
An object of the present invention is to provide a technique that enables good image quality correction.

  According to an aspect of the present invention, the brightness detected by each of the first optical sensor that detects the brightness around the projector body and the second photosensor that detects the brightness around the projection surface of the projector. An image quality correction system for a projector is provided, comprising image quality correction means for correcting the image quality of the projector by the image quality correction element selected based on the image quality correction element.

  According to another aspect of the present invention, each of the first optical sensor that detects the brightness around the projector body and the second optical sensor that detects the brightness around the projection surface of the projector is detected. An image quality of a projector, comprising: an image quality correction unit that obtains an average value of brightness and corrects the image quality of the projector by the image quality correction element selected based on a magnitude relationship between the average value and a certain threshold value A correction system is provided.

  It is preferable to correct the color temperature deviation depending on the screen based on the detection value of the optical sensor that detects the color temperature of the projection surface of the screen. For example, the values of DLP R-GAIN and B-GAIN (G-GAIN is fixed) are controlled.

As described above, ambient brightness can be measured with high accuracy, and further, by selecting an image quality correction element, fine image quality correction can be achieved.
By detecting the ambient light with a plurality of optical sensors and using the average value as the detection value, the ambient brightness can be measured with high accuracy, and further, the image quality can be finely corrected by selecting an image quality correction element.

  Also, the average value of the light sensor that detects the brightness around the projection surface of the screen and the light sensor that detects the brightness around the main body is obtained, and an image quality correction factor is determined depending on whether the average value exceeds a certain threshold value. By selecting and assigning priorities, it is possible to obtain a more dynamic image quality correction effect.

  Furthermore, the average value of the optical sensor that detects the brightness around the projection surface of the screen and the optical sensor that detects the brightness around the main body is obtained, and the projection light amount control is performed depending on whether or not the average value exceeds a certain threshold. Select a table prepared in advance (for example, the optical aperture is fully open / squeezed, the lamp power is high power / power save mode, SLR on / off for DLP type, etc.), and video signal level control is performed by the optical sensor. By performing linear control according to the detection value, control with a large dynamic range and control with a fixed amount of light for projection can be controlled relatively easily, and there are large image quality correction effects and energy saving effects.

  In addition, the color temperature of the projection surface of the screen can be detected by a color temperature detection light sensor to compensate for the difference in color depending on the type of screen, so that the accurate color temperature can be obtained, and high image quality evaluation is possible. Has the effect of

  In the image quality correction technique according to the present invention, in order to effectively correct the image quality, a combination of elements used for image quality correction is appropriately selected depending on whether the surrounding brightness is dark or bright. Thereby, dynamic correction and effective image quality correction with high energy efficiency can be performed. For example, when the ambient brightness is dark, the image quality (contrast, bright (element 4), γ correction, etc. (element 1)) is controlled according to the brightness, and the optical aperture is reduced (element 2). ) (High contrast mode) and a state in which the power of the lamp is reduced (element 5) (power save mode), it is possible to save energy and to perform extremely good image quality correction. When the ambient brightness is bright, the effect of image quality correction is poor, so the optical aperture is opened (element 2) (hibright mode), the lamp power is increased (element 5), and the dynamic range is adjusted. A wide and bright projected image can be obtained.

  That is, the image quality correction technique according to the present invention is based on the detected values of the first photosensor provided around the projector body and the second photosensor provided around the projection surface (screen). Is detected accurately, and the detection signal is input to the control unit (image quality correction unit) of the projector body. If the signal level is below a certain threshold, the surrounding brightness is judged to be dark, and the signal level is above a certain threshold. In the case, the surrounding brightness is judged to be bright.

  If it is determined that the surrounding is dark, the image quality correction is performed in the contrast priority mode. For example, the optical aperture (element 2) is narrowed as the first priority, the lamp power (element 5) is controlled in a small direction as the second priority, and the image quality correction (contrast, bright, γ correction) of the video signal as the third priority (Element 4 and Element 1) are performed according to the brightness, and image quality correction is performed with a more specific gravity on the contrast ratio. Thereby, the dynamic range of image quality correction can be expanded, and a large image quality correction effect can be obtained with power saving.

  If it is determined that the surroundings are bright, the image quality correction is performed in the brightness priority mode. For example, the optical aperture (element 2) is set to the opening direction as the first priority, the lamp power (element 5) is set to the larger direction as the second priority, and SLR is set as the third priority for the single plate type (color wheel type) DLP. The brightness of the projected image can be increased by turning on (element 3) and correcting the image quality (contrast, bright, γ correction) of the video signal according to the brightness as the fourth priority (elements 4 and 1).

As described above, by combining the elements in consideration of the priority order, a large dynamic range can be obtained when the surroundings are bright, and more effective image quality correction can be achieved.
In addition, paying attention to the change in color temperature depending on the type of screen, etc., in order to correct the color temperature correctly, a light sensor that detects the color temperature is provided in the projector body, The source of the reference signal to project (for example, 75% white signal) is built in the main body, the color temperature of the image projected on the screen is detected, and the values of R-GAIN and B-GAIN of DLP are detected by the color temperature correction circuit. The color temperature can be automatically corrected by controlling the color temperature.

  Hereinafter, an image quality correction system according to an embodiment of the present invention will be described with reference to the drawings based on the above concept. FIG. 1 is a diagram illustrating a configuration example of an image quality correction system according to the present embodiment. As shown in FIG. 1, the image quality correction system 1 according to the present embodiment includes a first photosensor 2 and, for example, a plurality of second photosensors 18 to 23. Reference numeral 24 denotes an optical tunnel. The first optical sensor 2 is an optical sensor that measures the ambient light of the projector main body, and is provided, for example, on a side surface or an upper surface of the main body. The second optical sensor is an optical sensor that measures the light of the projection screen 17, and a plurality of second optical sensors are provided, for example, around the projection image plane.

  The first light sensor 2 measures the brightness (first measurement value) of the ambient light of the main body, and the second light sensors 18 to 23 detect, for example, the average value of the detected light amount when projected onto the projection screen. (Second measurement value) is obtained, and the first measurement value and the second measurement value are taken into account, for example, an average value of the first measurement value and the second measurement value is obtained. (Optional value) In the following cases, it is determined that the surroundings are dark, and the image quality correction is preferentially performed in the following order as the contrast priority mode.

  For example, the control unit (CPU) 3 controls the optical diaphragm control circuit 26 of the optical diaphragm (the illumination system variable diaphragm 13 and the projection system variable diaphragm 15) as the first priority (element 2), and the second priority. The CPU 3 controls the lamp control circuit 7 in the direction in which the lamp power decreases (element 5), and the CPU 3 controls the image quality correction (contrast, bright, γ correction) (elements 4, 1) of the video processing circuit 4 as the third priority. Is performed according to the brightness, image quality correction with a larger contrast ratio is performed, the dynamic range of image quality correction in the dark direction is expanded, and a large image quality correction effect is obtained with power saving. Control of the optical aperture (element 2) and lamp power (element 5) described above controls the amount of light of the projection light, and image quality correction (contrast, brightness, γ correction) (elements 4 and 1) of the image processing circuit is signal level. Take control.

  2A to 2C are examples of tables relating to image quality correction elements according to the present embodiment, and are diagrams showing priorities when the image quality correction effect is maximized. As shown in FIG. 2A, for the video signal, the γ correction of element 1 and the contrast / brightness of element 4 are related. Regarding the amount of light, the optical aperture of element 2, the SLR of element 3, and the lamp power of element 5 are related. Actually, the priority order of elements is different between the DLP type (FIG. 2B) and the liquid crystal type (FIG. 2C). FIG. 5 is a flowchart showing the flow of processing based on the table shown in FIG. This will be described with reference to FIG. Processing is started in step S1, and it is determined in step S2 whether or not the average value of the detection values of the optical sensor is larger than a certain threshold A (arbitrary value). When the average value of the detection values of the optical sensor is larger than a certain threshold A (arbitrary value), it is determined that the image is bright, and the image quality correction is preferentially performed in the following order as the brightness priority mode. For example, in step S2, the CPU 3 controls the control circuit 26 of the optical diaphragm (the illumination system variable diaphragm 13 and the projection system variable diaphragm 15) as the first priority in the opening direction (element 2), and in step S3, the second priority is given. In the case where the CPU 3 controls the lamp control circuit 7 in the direction in which the lamp power is increased (element 5), and in step S5, it is determined whether or not the DLP method is used, and the third priority is the single plate type (color wheel type) DLP method. In step S6, the CPU 3 controls the color wheel 11 and the DMD 5 via the SLR control circuit 25 so as to turn on SPOKE LIGHT RECAPTURE (SLR) (element 3). In step S7, the CPU 3 sets the fourth priority as the fourth priority. Image quality correction of image processing circuit 4 (contrast, bright, γ correction) (elements 4, 1 To expand the dynamic range of the bright direction of the image quality correction by performing corresponding control of the brightness. On the other hand, if it is not the DLP system (for example, in the case of the liquid crystal system) in step S5, the process proceeds to step S7 as it is, and the CPU 3 performs image quality correction (contrast, bright, γ correction) of the video processing circuit 4 as the fourth priority (element 4 , 1) according to the brightness, the dynamic range of image quality correction in the bright direction is expanded. Next, the process is terminated (step S11).

  In step S2, if the average value of the detection values of the optical sensor is smaller than a certain threshold value A (arbitrary value), it is determined that the surrounding brightness is dark, and the optical aperture priority mode is preferentially corrected in the following order. I do. That is, in step S8, the optical aperture is narrowed down (element 2). In step S9, the lamp power (element 5) is minimized (power save mode), for example. In step S10, image quality correction (contrast, bright, .gamma. Correction) is performed. The control of (elements 4 and 1) is adjusted for the dark mode, and the process ends (step S11). By performing the processing as described above, it is possible to perform image quality correction to an image having “brightness”. The priority order is 1)> 2)> 3)> 4).

  The single plate DLP method (color wheel type) SLR control described above actually controls the amount of light of the projection light. The color temperature is corrected by, for example, projecting a 75% white signal for color temperature adjustment from the projector onto the screen, detecting the color temperature of the projection surface by the light sensor 40 for color temperature detection, and DMD through the DMD control circuit 39 in the CPU 3. Color temperature correction is performed by controlling R-GAIN and B-GAIN of the chip 5.

  Next, image quality correction according to the second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is an example of a table relating to image quality correction elements in the case of the DLP method in image quality correction according to the present embodiment, and is a diagram showing the priority order for each element. FIG. 5 is an example of a table relating to image quality correction elements in the case of the liquid crystal type in the image quality correction according to the present embodiment, and is a diagram showing the priority order for each element. FIG. 6 is a flowchart showing the flow of image quality correction processing according to this embodiment.

  First, processing is started (step S21), and in step S22, it is determined whether or not the average value of the detection values of the optical sensor is greater than a certain threshold A (arbitrary value). When the average value of the detection values of the optical sensor is larger than a certain threshold A (arbitrary value), it is determined that the image is bright, and the image quality correction is preferentially performed in the following order as the brightness priority mode. For example, in step S23, the CPU 3 controls the control circuit 26 of the optical diaphragm (the illumination system variable diaphragm 13 and the projection system variable diaphragm 15) in the opening direction (element 2), and in step S24, the lamp power is increased (element 5). ), The CPU 3 controls the lamp control circuit 7. In step S25, the CPU 3 determines whether or not the DLP method is used. If the single plate type (color wheel type) DLP method is given as the third priority, the process proceeds to step S26. The CPU 3 controls the color wheel 11 and the DMD 5 via the SLR control circuit 25 so as to turn on (SLR) (element 3), and the process ends in step S28. On the other hand, if it is not the DLP system (for example, in the case of the liquid crystal system) in step S25, the process proceeds to step S28 as it is, and the process is terminated. That is, in this embodiment, step S7 in FIG. 6 is omitted.

  In step S22, when the average value of the detection values of the optical sensor is smaller than a certain threshold A (arbitrary value), it is determined that the surrounding brightness is dark. In step S27, image quality correction (contrast, bright, γ correction) is performed. The control of (element 4, 1) is adjusted for the dark mode, and the process ends (step S28). In this case, step S8 is omitted compared to FIG. Even with this processing, the dynamic range can be easily expanded in image quality correction. The priority order is 1)> 2)> 3) in the DLP system and 1)> 2) in the liquid crystal system.

  FIGS. 7A to 7C are diagrams illustrating an example of a correction table used in the image quality correction processing according to each of the above embodiments. As shown in FIG. 7A, the control of the projection light quantity has a fixed value table, and the table is selected depending on whether or not the detection value of the optical sensor exceeds a certain threshold A, and the control of the video signal is It can control according to the detection value of an optical sensor.

  That is, the average value of the optical sensor that detects the brightness around the projection surface of the screen and the optical sensor that detects the brightness around the main body is obtained, and whether the average value exceeds a certain threshold value, A table prepared in advance shown in FIG. 7 (for example, the optical aperture is selected from the fully open state and the fully closed state, the lamp power is selected from the high power state and the power saving state, for example, in the case of the DLP type (FIG. 7 (b )) Select SLR ON / OFF, etc., and video signal level control (γ correction, contrast, brightness) performs linear variable control according to the detection value of the optical sensor. Thereby, by controlling the dynamic range largely and setting the projection light quantity to a fixed value, a large image quality correction effect and energy saving effect can be obtained relatively easily. In the case of the liquid crystal type of FIG. 7C, the element 3 is not related.

  Also in this embodiment, the color temperature of the projection surface is detected by the color temperature sensing optical sensor 40, and the CPU 3 controls the R-GAIN and B-GAIN of the DMD chip 5 through the DMD control circuit 39 to correct the color temperature. It can be performed.

As described above, the present invention has been described according to the embodiment. However, the present invention is not limited to these examples, and various modifications can be made.
For example, as an indication of ambient brightness, the average value of the measured values of the first photosensor and the second photosensor is used in the above embodiment, but there are a plurality of units arranged around the projection surface. Since the screen periphery is brighter than the peripheral part of the main body, it is corrected (A) by applying an appropriate correction coefficient (K1), and the measured value of the sensor provided on the main body (multiplying the correction coefficient) is obtained. (No) (B) may be obtained, and an image quality correction element may be controlled using an average value of (A) and (B).

  The present invention can be used for an image quality correction circuit of a projector and a projector including the same. In particular, it can be used for entertainment-related applications such as a home theater. For example, videos, DVDs, high-definition sources, and the like can be viewed with high-quality image with “Merihari” effect.

1 is a configuration diagram of an image quality correction system according to a first embodiment of the present invention. 2A to 2C are table diagrams showing the types of image quality correction elements and the combination priorities according to the first embodiment of the present invention. It is a table figure which shows the priority of each element in the DLP system projector by the 2nd Embodiment of this invention. It is a table figure of the priority of each element in the liquid crystal projector by the 2nd Embodiment of this invention. It is a flowchart figure which shows the flow of the image quality correction process at the time of the maximum effect by the 1st Embodiment of this invention. It is a flowchart figure which shows the flow of the image quality correction process by the 2nd Embodiment of this invention. FIGS. 7A to 7C are image quality correction table diagrams according to the first and second embodiments of the present invention. It is drawing which shows schematic structure of the conventional projector.

Explanation of symbols

1 DLP projector, 2 optical sensor (main body), 3 CPU, 4 video processing circuit, 5 DMD chip, 6 lamp, 7 lamp control circuit, 8 prism, 9 IR cut mirror, 10 condenser lens, 11 color wheel, 12 relay lens , 13 Lighting system variable aperture, 14 Hold mirror, 15 Projection system variable aperture, 16 Projection lens, 17 Screen, 18, 19, 20, 21, 22, 23 Optical sensor (screen part), 24 optical tunnel, 25 SLR control circuit , 26 Optical aperture control circuit, 31 Liquid crystal projector, 32 Optical sensor, 33 CPU, 34 Video processing circuit, 35 Liquid crystal panel, 36 Lamp, 37 Lamp control circuit, 38 Video projection surface (screen) 39 DMD control circuit, 40 Color temperature Sensing light sensor

Claims (9)

  An average value of the brightness detected by each of the first light sensor for detecting the brightness around the projector body and the second light sensor for detecting the brightness around the projection surface by the projector is obtained, and the average An image quality correction system for a projector, comprising: first image quality correction means for correcting the image quality of the projector by an image quality correction element selected based on a magnitude relationship between a value and a threshold value.   The first image quality correction means selects a priority image quality correction element based on the magnitude relationship from among a plurality of image quality correction element candidates, and based on the image quality correction element selected preferentially, The projector image quality correction system according to claim 1, wherein the image quality correction system is a control unit that corrects the image quality. Depending on whether the average value exceeds the threshold,
For projection light quantity control, select and control a table relating to the image quality correction element prepared in advance,
3. The image quality correction system according to claim 1, wherein the video signal level control performs linear control in accordance with a detection value of the optical sensor.   And a second image quality correction unit that corrects a color temperature shift depending on the screen based on a detection value of a third optical sensor that detects a color temperature of a projection surface of the screen projected by the projector. The image quality correction system according to any one of claims 1 to 3.   Image quality correction selected based on the brightness detected by each of the first light sensor for detecting the brightness around the projector body and the second light sensor for detecting the brightness around the projection surface of the projector An image quality correction system for a projector, comprising image quality correction means for correcting the image quality of the projector according to elements.   An image quality correction system comprising image quality correction means for correcting a video signal of a projector and a projection light quantity based on brightness around a projection surface of a screen and brightness around a projector body.   The image quality correcting means narrows down the optical aperture as the first priority and decreases the lamp power as the second priority in the contrast priority mode when the first and second light sensors determine that the surrounding is dark. The image quality correction system according to any one of claims 1 to 6, wherein the image quality correction of the video signal is performed according to brightness as a third priority.   The image quality correcting means sets the optical aperture in the open direction as the first priority and sets the lamp power as the second priority in the brightness priority mode when the first and second light sensors determine that the surrounding is bright. The image quality correction system according to claim 7, wherein the image quality correction system is set in a large direction.   The projector apparatus provided with the image quality correction system of any one of Claim 1-8.

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