JP3695374B2 - Focus adjustment device and focus adjustment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a focus adjustment apparatus and a focus adjustment method for adjusting the position of a liquid crystal panel of an optical system of a projection display device, and in particular, the position of the liquid crystal panel by analyzing an image captured by moving the optical axis position of the liquid crystal panel. The present invention relates to a focus adjustment apparatus and a focus adjustment method for performing adjustment.
[0002]
[Prior art]
In general, a liquid crystal projector uses three liquid crystal panels of red, green, and blue to create a monochromatic image, and colors the red, green, and blue monochromatic images on a dichroic prism to create a projected image.
[0003]
In the focus adjustment process of the LCD projector, the green projected image with the clearest color contrast is used as the reference position, and the remaining red and blue projected images are matched as much as possible to the corresponding projected pixel positions of the displayed green. Overlapping the images, and then projecting with a single color at this position, the projected pixels on the projected surface are the least blurred, and the liquid crystal of each color is in the position where the projected pixels of each color projection image and the pixel separation are the clearest It is necessary to adjust the panel position.
[0004]
Conventional focus adjustment is implemented on a liquid crystal projector by projecting a reference green image onto a screen as a projection surface, and the operator visually confirming how the projected pixels are blurred on the screen. The optical axis of the LCD panel was adjusted. For adjusting the optical axis of the liquid crystal panel, there are 6 liquid crystal panel positions X, Y, Z, a rotation angle θ on the Z axis, a panel tilt angle Xθ in the X axis direction, and a panel tilt angle Vθ in the Y axis direction. The three axes of the position Z of the liquid crystal panel, the panel tilt angle Xθ in the X-axis direction, and the panel tilt angle Vθ in the Y-axis direction are adjusted by a six-axis manipulator capable of adjusting the optical axis of the axis. The focus plane position of the liquid crystal panel, which is optically determined by the positional relationship of the axes, is determined. The focus adjustment is performed for the three liquid crystal panels of red, green, and blue. After determining the focus surface position of the liquid crystal panel for each color, the liquid crystal panel is joined to the optical unit and the adjustment is finished.
[0005]
Japanese Patent Laid-Open No. 2000-147694 discloses a Z-axis direction of a liquid crystal light valve when images of projected pixels on a screen are imaged by a camera, luminances are totaled, luminance dispersion is obtained, and an image having the largest variance is taken. A technique for automatically performing focus adjustment at the position is disclosed.
[0006]
[Problems to be solved by the invention]
However, in the prior art, due to the difference in the visibility between the camera sensitivity and the naked eye, the brightness values of the blue and red colors and the appearance with the naked eye are different, so it is difficult to set the camera brightness setting appropriately. However, in actual focus adjustment, it is necessary to check the image projected on the screen not only with the camera but also with the naked eye.
[0007]
Furthermore, with the conventional technology, the projected image on the screen is not easily displayed due to the influence of the external light of the surrounding environment being adjusted or the reflected light from the projection surface, and the original properties of brightness distribution of the projected pixels are difficult to see. In the case of blue, which is extremely poor, there is a problem that it is difficult to accurately align the optical axis position with the position where the focus of the projected image is clearest (hereinafter referred to as the focus position) even if automatic focus adjustment is performed. It was.
[0008]
Furthermore, in the prior art, the projected pixels of the projected image are actually different in the direction of blur in the vertical (Y) direction and the horizontal (X) direction, and the shape of the projected image changes with the movement of the optical axis of the liquid crystal panel. Since it constantly changes, there is a problem that the focus position cannot be determined accurately only by the luminance dispersion of the projection pixels.
[0009]
The present invention has been made in view of such a problem, and an object of the present invention is to appropriately set the luminance setting of an image captured by the camera regardless of the difference in visibility between the camera sensitivity and the naked eye. It is possible to provide a focus adjustment device and a focus adjustment method capable of accurately adjusting the optical axis position to the focus position by performing automatic focus adjustment.
[0010]
Furthermore, the purpose of the present invention is to clarify the original nature of the luminance dispersion of the projection pixel, and to adjust the optical axis position to the focus position by automatically adjusting the focus even in the case of blue with extremely poor visibility. Therefore, it is possible to provide a focus adjustment device and a focus adjustment method capable of accurately adjusting the focus.
[0011]
Further, the present invention aims to set the optical axis position to the focus position by automatically adjusting the focus in consideration of the blurring in the vertical (Y) direction and the horizontal (X) direction of the projection pixel of the projected image. A focus adjustment device and a focus adjustment method that can be accurately adjusted are provided.
[0012]
[Means for Solving the Problems]
  In order to solve the above problems, the present invention has the following configuration.
  The present invention is a focus adjustment device for adjusting an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel, and images the image while moving the optical axis position in the normal direction of the liquid crystal panel. Based on the luminance distribution of the pseudo monochrome image generated by the imaging means for imaging, the pseudo monochrome image generating means for generating a pseudo monochrome image from the image captured by the imaging means, and the pseudo monochrome image generating means A focus adjustment device comprising: focus search means for searching for an optical axis position; and optical axis adjustment mechanism means for moving the liquid crystal panel to the optical axis position searched by the focus search means.
  Further, according to the present invention, the pseudo monochrome image generation means has a luminance distribution I of the pseudo monochrome image, and the luminance distributions of the color components of the image are R, G, and B, respectively, I = (28 * R + 77 * G + 151 * B) / 256. The focus adjustment apparatus is characterized in that the pseudo-monochrome image is generated.
  The present invention further includes contrast enhancement means for enhancing the contrast of the pseudo monochrome image, and the focus search means is configured to adjust the optical axis position based on the luminance distribution of the pseudo monochrome image whose contrast is enhanced by the contrast enhancement means. This is a focus adjustment device characterized by searching for.
  Furthermore, the present invention is the focus adjustment device, wherein the contrast emphasizing means averages the number of pixels in each luminance value of the pseudo monochrome image.
  The present invention further includes projection processing means for performing luminance integration for each direction in the X direction and Y direction of the pseudo monochrome image, and the focus search means is configured to perform the luminance integration for the X and Y directions by the projection processing means. A focus adjustment device that searches an optical axis position based on a pseudo monochrome image.
  Further, according to the present invention, the maximum luminance value PXmax in the X direction and the minimum luminance value PXmin in the X direction and the luminance in the Y direction of the pseudo-monochrome image integrated in the X and Y directions by the projection processing unit. A light amount analyzing means for searching for the maximum value PYmax of the integral value and the minimum value PYmin of the luminance integral value in the Y direction for each optical axis position in the normal direction of the moved liquid crystal panel; A focus adjustment device that searches for an optical axis position based on PXmax, PXmin, PYmax, and PYmin searched by a light amount analysis unit.The
TheThe present invention further includes contrast sensitivity calculation means for calculating contrast sensitivity Sx and Sy for each of the X and Y directions from PXmax, PXmin, PYmax and PYmin searched by the light amount analysis means, and the focus search means The focus adjustment device is characterized in that the optical axis position is searched based on the contrast sensitivity Sx and Sy calculated by the contrast sensitivity calculation means.
  Further, according to the present invention, the contrast sensitivity calculation means sets the contrast sensitivities Sx and Sy to Cx = (PXmax−PXmin) / (PXmax + PXmin), Cy = (PYmax−PYmin) / (PYmax + PYmin), Sx = 1 / Cx, Sy = 1 / Cy, the focus adjustment device is characterized in that the calculation is performed.
  Furthermore, the present inventionA focus adjustment device that adjusts an optical axis position of the liquid crystal panel based on an image that has passed through the liquid crystal panel, and an imaging unit that captures the image while moving an optical axis position in a normal direction of the liquid crystal panel; , The maximum value PXmax of the X-direction luminance integral value, the minimum value PXmin of the X-direction luminance integration value, the maximum YY-direction luminance integration value PYmax, and the Y-direction luminance integration value of the image captured by the imaging means. Light quantity analysis means for searching for the optical axis position in the normal direction of the liquid crystal panel to which the minimum value PYmin has been moved, and contrast sensitivity for each of the X and Y directions from PXmax, PXmin, PYmax and PYmin searched by the light quantity analysis means Contrast sensitivity calculation means for calculating Sx, Sy, and the contrast sensitivity Sx calculated by the contrast sensitivity calculation means A focus search means for searching an optical axis position on the basis of sy, the liquid crystal panel in the searched optical axis position by the focus search means And the contrast sensitivity calculation means sets the contrast sensitivities Sx and Sy to Cx = (PXmax−PXmin) / (PXmax + PXmin), Cy = (PYmax−PYmin) / (PYmax + PYmin). ), Sx = 1 / Cx, and Sy = 1 / Cy.It is.
  Further, according to the present invention, the focus search unit searches for an optical axis position where the average value of the sum of the contrast sensitivities Sx and Sy calculated by the contrast sensitivity calculation unit is a minimum value. It is.
  Further, according to the present invention, the imaging unit causes the four corners of the video to be imaged, and the focus search unit searches the optical axis positions of the four corners captured by the imaging unit, respectively. It is.
  Furthermore, the present invention corrects the optical axis in the normal direction of the liquid crystal panel, the tilt angle Xθ in the X-axis direction, and the tilt angle Vθ in the Y-axis direction based on the optical axis positions of the four corners searched by the focus search means. An optical axis control means for calculating a correction value to be corrected is provided.
  Furthermore, the present invention is a focus adjustment apparatus in which the imaging means images the image projected on a screen on which a white material panel having a small surface roughness is stretched.
  The present invention further provides a focus adjustment method for adjusting an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel, wherein the image is displayed while moving the optical axis position in the normal direction of the liquid crystal panel. An image is picked up as an image, a pseudo monochrome image is generated from the image, an optical axis position is searched based on the luminance distribution of the pseudo monochrome image, and the liquid crystal panel is placed at the optical axis position searched using the optical axis adjustment mechanism means. It is a focus adjustment method characterized by moving.
  Further, according to the present invention, the pseudo-monochromatic image has a luminance distribution I, and if the luminance distribution of the color components of the image is R, G, and B, respectively, I = (28 * R + 77 * G + 151 * B) / 256. A focus adjustment method characterized by generating a monochrome image.
  Furthermore, the present invention is a focus adjustment method characterized by enhancing the contrast of the pseudo monochrome image and searching for the optical axis position based on the luminance distribution of the pseudo monochrome image with the contrast enhanced.
  Furthermore, the present invention is a focus adjustment method characterized in that the contrast is enhanced by averaging the number of pixels in each luminance value of the pseudo monochrome image.
  Further, the present invention is characterized by performing luminance integration for each direction in the X and Y directions of the pseudo monochrome image, and searching for an optical axis position based on the pseudo monochrome image obtained by luminance integration for the X and Y directions. This is the focus adjustment method.
  Furthermore, the present invention relates to a maximum value PXmax in the X-direction luminance integral value, a minimum value PXmin in the X-direction luminance integration value, and a maximum value in the Y-direction luminance integration value. The minimum value PYmin of the luminance integrated value in PYmax and Y direction is searched for each optical axis position in the normal direction of the moved liquid crystal panel, and the optical axis position is determined based on the searched PXmax, PXmin, PYmax and PYmin. A focus adjustment method characterized by searching.The
TheFurther, the present invention is characterized in that the contrast sensitivities Sx and Sy are calculated for the X and Y directions from the searched PXmax, PXmin, PYmax and PYmin, and the optical axis position is searched based on the contrast sensitivities Sx and Sy. This is the focus adjustment method.
  Further, the present invention defines the contrast sensitivities Sx and Sy as Cx = (PXmax−PXmin) / (PXmax + PXmin), Cy = (PYmax−PYmin) / (PYmax + PYmin), Sx = 1 / Cx, Sy = 1 / Cy. The focus adjustment method is characterized in that it is calculated as follows.
  Furthermore, the present inventionA focus adjustment method for adjusting an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel, wherein the image is captured while moving an optical axis position in a normal direction of the liquid crystal panel, and the imaging Value PXmax of the integrated luminance value in the X direction of the processed image , The minimum value PXmin of the luminance integral value in the X direction, the maximum value PYmax of the luminance integral value in the Y direction, and the minimum value PYmin of the luminance integral value in the Y direction for each optical axis position in the normal direction of the liquid crystal panel that has been moved From the searched PXmax, PXmin, PYmax and PYmin, contrast sensitivity Sx and Sy are classified into Xx and Y directions by Cx = (PXmax−PXmin) / (PXmax + PXmin), Cy = (PYmax−PYmin) / (PYmax + PYmin),
Sx = 1 / Cx and Sy = 1 / Cy are defined and calculated, the optical axis position is searched based on the calculated contrast sensitivities Sx and Sy, and the optical axis position searched using the optical axis adjustment mechanism means is obtained. Focus adjustment method characterized by moving said liquid crystal panelIt is.
  Furthermore, the present invention is a focus adjustment method characterized by searching for an optical axis position at which an average value of the calculated sums of the contrast sensitivities Sx and Sy is a minimum value.
  Furthermore, the present invention is a focus adjustment method characterized in that four corners of the video are imaged and the optical axis positions of the captured four corners are respectively searched.
  Further, the present invention calculates correction values for correcting the optical axis in the normal direction of the liquid crystal panel, the tilt angle Xθ in the X-axis direction, and the tilt angle Vθ in the Y-axis direction based on the searched optical axis positions at the four corners. Then, the focus adjustment method is characterized by.
  Furthermore, the present invention is a focus adjustment method characterized in that the image projected on a screen on which a white material panel having a small surface roughness is stretched is captured.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing the configuration of the embodiment of the focus adjusting apparatus according to the present invention, FIG. 2 is a plan view showing the positional relationship of the color CCD camera shown in FIG. 1, and FIG. 4 is a side view showing the positional relationship of the color CCD camera shown in FIG. 1, FIG. 4 is a diagram showing the imaging position on the screen by the color CCD camera shown in FIG. 1, and FIG. 5 is the image recognition process shown in FIG. FIG. 6 is a diagram showing the positional relationship between the adjustment optical axis of the optical components of the liquid crystal projector moved by the optical axis adjustment mechanism shown in FIG. 1 and the liquid crystal panel for each color. .
[0015]
In the present embodiment, as shown in FIG. 1, color CCD cameras 3 a, 3 b, 3 c, 3 d, A / D conversion circuit 11, digital image integrator 12, image memory 13, and image recognition processing unit 14. And an optical axis control unit 15 and an optical axis adjustment mechanism unit 8. Although not shown in FIG. 1, the A / D conversion circuit 11 is also provided between the color CCD cameras 3b, 3c, and 3d and the digital image integrator 12, similarly to the color CCD camera 3a. Yes.
[0016]
As shown in FIGS. 2 and 3, the color CCD cameras 3a, 3b, 3c, and 3d capture four corners of the projected image projected on the screen projection surface of the screen 2 from the liquid crystal projector 1 that is a projection display device. Placed in position. A video signal generator 4 is connected to the liquid crystal projector 1, and the liquid crystal projector 1 passes the liquid crystal panel corresponding to the corresponding color in response to the monochromatic raster scan video provided from the video signal generator 4. Then, a single color projection image is projected onto the screen 2. In addition, in order to prevent light other than the projected image from the liquid crystal projector 1, the dark curtain tent 5 blocks all the projection range of the liquid crystal projector 1 including the screen projection surface from outside light.
[0017]
As shown in FIG. 4, the screen 2 is provided with white material panels 6a, 6b, 6c, 6d such as photo printing paper having a small surface roughness and a standard white board, each of which has four corners of the projected image. It is placed in a position that fits. The screen 2 and the white material panels 6 a, 6 b, 6 c, 6 d are installed so as to be perpendicular to the projection optical axis of the liquid crystal projector 1. When a standard white board is used as the white material panels 6a, 6b, 6c, 6d, the surface roughness is preferably 0.05 Z or less with an average roughness of 10 points, and even when using photo printing paper. It is preferable to use one having a 10-point average roughness of 0.05 Z or less.
[0018]
The color CCD cameras 3a, 3b, 3c, and 3d are installed at positions where the four corners of the projected images on the white material panels 6a, 6b, 6c, and 6d are sufficiently accommodated, and are projected onto the white material panels 6a, 6b, 6c, and 6d. The projected image of the selected area is captured.
[0019]
The A / D conversion circuit 11 performs A / D conversion on the color images captured by the color CCD cameras 3a, 3b, 3c, and 3d, respectively. A / D conversion is performed for each of the red (R), green (G), and blue (B) colors that are color components of the color image.
[0020]
The digital image integrator 12 generates integrated digital image data obtained by integrating color images captured by the color CCD cameras 3a, 3b, 3c, and 3d installed at the four corners of the projected video and A / D converted. The integrated digital image data is generated for the purpose of handling four images taken by the four cameras 3a, 3b, 3c, and 3d as one frame image signals, and is generated for each color component.
[0021]
The image memory 13 stores the integrated digital image data of R color, G color, and B color generated by the digital image integrator 12 for each color component.
[0022]
As shown in FIG. 5, the image recognition processing unit 14 performs contrast calculation processing with the pseudo monochrome image generation unit 16, the contrast image generation unit 17, the focus inspection area generation unit 18, and the projection processing unit 19 that perform image recognition processing. The in-area light quantity analysis unit 20, the contrast sensitivity calculation unit 21, and the contrast search unit 22 are configured.
[0023]
The pseudo monochrome image generation unit 16 uses a luminance value of the integrated digital image data of each color component stored for each color component in the image memory 13 to generate a pseudo monochrome image that is a grayscale image close to the light intensity on the projection surface. Generate.
[0024]
The contrast image generation unit 17 performs contrast enhancement processing of the pseudo monochrome image generated by the pseudo monochrome image generation unit 16 to enhance the luminance distribution feature while inheriting the luminance distribution feature on the projection surface of the screen 2. By increasing the luminance difference between the bright and dark portions of the projected image, the contrast is increased and the image is sharpened.
[0025]
The focus inspection area generation unit 18 sets a focus inspection area in the image area of the camera visual field position corresponding to the four imaging positions on the screen 2.
[0026]
The projection processing unit 19 performs luminance integration for each of the X and Y directions in the focus inspection area set by the focus inspection area generation unit 18, and calculates the light intensity distribution on the projection surface of the projection pixel region for each X and Y direction. It is expressed as a characteristic variation of the emphasized sinusoidal shape.
[0027]
The in-area light amount analysis unit 20 searches for the maximum value and the minimum value of the luminance integrated values in the X and Y directions obtained by the projection processing unit 19.
[0028]
The contrast sensitivity calculation unit 21 calculates the contrast sensitivity from the maximum value and the minimum value of the luminance integrated values in the X and Y directions searched by the in-area light amount analysis unit 20.
[0029]
The contrast search unit 22 searches the minimum value of the contrast sensitivity for each focus inspection area at each position where the optical axis is step-moved within the optical axis movement range, and the contrast sensitivity is the minimum value for each focus inspection area. Is obtained as the focus position at which the focus of the projected image is clearest and the projected image is clearest.
[0030]
The optical axis control unit 15 uniquely determines the focus gravity center and the inclination correction values of the liquid crystal panels 9a, 9b, and 9c in the liquid crystal projector 1 based on the focus position for each focus inspection area obtained by the contrast search unit 22. The calculated focus gravity center and the correction value are sent to the optical axis adjustment mechanism unit 8 as command values.
[0031]
The optical axis adjustment mechanism unit 8 is a mechanism that adjusts the mounting position of the optical components of the liquid crystal projector 1 based on the command value from the optical axis control unit 15, and the liquid crystal panels 9a, 9b, and 9c shown in FIG. The optical axis is adjusted when the light from the panels 9a, 9b, and 9c is attached to the dichroic prism 10 that performs color composition.
[0032]
In FIG. 6, X, Y, Z, θ, Xθ, and Yθ indicate the adjustment optical axes of the liquid crystal panel 9 a (in charge of G color) that is moved by the optical axis adjustment mechanism unit 8. The incident light direction (normal direction) perpendicular to is defined as the Z axis. The position of the liquid crystal panel 9a is determined by six axes including the panel position X, Y, Z, the rotation angle θ on the Z axis, the panel tilt angle Xθ in the X axis direction, and the panel tilt angle Vθ in the Y axis direction. However, the focus adjustment is performed by adjusting the three adjustment optical axes of the Z axis, the Xθ axis, and the Yθ axis. The liquid crystal panel 9b responsible for the R color and the liquid crystal panel 9c responsible for the B color have the same optical axis coordinate arrangement.
[0033]
Next, the operation of the present embodiment will be described in detail with reference to FIG.
FIG. 7 is a flowchart for explaining the operation of the embodiment of the focus adjustment apparatus according to the present invention.
[0034]
First, the video signal generator 4 provides the liquid crystal projector 1 with a single color raster scan video (step A1), and the liquid crystal projector 1 uses the provided single color raster scan video for the corresponding liquid crystal panels 9a, 9b, 9c. Is passed through and is projected as a monochromatic projection image on the screen 2 (step A2). The monochromatic raster scan video is an image for performing focus adjustment. For the focus adjustment of the liquid crystal panel 9a in charge of G color, the monochromatic raster scan video of G color is used for focus adjustment of the liquid crystal panel 9b in charge of R color. The R single-color raster scan video is used for the focus adjustment of the liquid crystal panel 9c responsible for the B color, and the B single-color raster scan video is used. Hereinafter, an example of performing the focus adjustment of the liquid crystal panel 9a in charge of G color will be described.
[0035]
Next, each of the four corners of the G color projection image projected on the white material panels 6a, 6b, 6c, and 6d by the color CCD cameras 3a, 3b, 3c, and 3d is captured as a color image (step A3). A / D conversion is performed for each color component of each color image captured by the D conversion circuit 11 (step A4), and integrated digital image data obtained by integrating the four color images A / D converted by the digital image integrator 12 is obtained. Each color component is generated (step A5) and stored in the image memory 13 for each color component. The screen 2 is projected with the G color projection image that has passed through the liquid crystal panel 9a in charge of the G color. However, since the R color and B color components are actually included, the color CCD camera 3a, Images are taken as color images by 3b, 3c, and 3d.
[0036]
FIG. 8 is a diagram showing an example of integrated digital image data generated by the digital image integrator shown in FIG.
As shown in FIG. 8, the integrated digital image data generated by the digital image integrator 12 is obtained by integrating four color images captured by the color CCD cameras 3a, 3b, 3c, and 3d and A / D converted. In addition, each area corresponding to the color CCD cameras 3a, 3b, 3c, and 3d includes a bright portion of the projection pixel and a dark portion that becomes a break between the projection pixels. Further, the luminance distribution at the pixel position (x, y) in one frame of the integrated digital image data is R (x, y), G (x, y), B (x, y) for each color component in the image memory 13. y) (hereinafter described as R, G, and B, respectively). By integrating the images of the four color CCD cameras 3a, 3b, 3c, and 3d as integrated digital image data that can be confirmed on a single screen by the digital image data integrator 12, four images captured by the four cameras are displayed as one. It can be handled as an image signal of a frame, and when performing image processing and focus calculation processing in the image recognition processing unit 14, four images can be executed simultaneously, so that each color CCD camera 3a, 3b, 3c, 3d It is not necessary to perform image processing for each video, and the adjustment time can be shortened by reducing the number of times of imaging and the number of image processing operations.
[0037]
Next, a pseudo monochrome image is generated by the pseudo monochrome image generation unit 16 (step A6).
The pseudo monochrome image generation unit 16 reads the integrated digital image data stored in the image memory 13 from the image memory 13, and weights the luminance distributions R, G, and B of the respective color components of the integrated digital image data to make a monochrome image. Generate a monochrome image. As the weighting of the luminance distributions R, G, and B when generating the pseudo monochrome image, for example, the luminance distribution I (x of the pseudo monochrome image on the pixel position (x, y) in one frame in the integrated digital image data is used. , Y)
I (x, y) = (28 * R + 77 * G + 151 * B) / 256
To generate a pseudo monochrome image. The formula is an application of the luminance signal and color signal conversion formula described in page 105 of “Practical Image Processing Learned in C Language (Ohm)”.
[0038]
Next, contrast enhancement processing is performed on the pseudo monochrome image generated by the pseudo monochrome image generation unit 16 by the contrast image generation unit 17 (step A7).
FIG. 9 is a histogram of the number of pixels for each luminance value for explaining the contrast enhancement processing by the contrast image generation unit shown in FIG. 5, and FIG. 10 shows the contrast enhancement processing by the contrast image generation unit shown in FIG. FIG. 11 is an explanatory diagram for explaining an algorithm. FIG. 11 is a graph for comparing luminance distributions in the same region before and after the contrast enhancement processing by the contrast image generation unit shown in FIG.
[0039]
As shown in FIG. 9A, the contrast image generation unit 17 obtains the total number of pixels of the pseudo monochrome image generated by the pseudo monochrome image generation unit 16, takes a histogram for each luminance value, and FIG. As shown, the number of pixels in each luminance value is averaged.
[0040]
In the pseudo monochrome image, when the number of pixels is distributed in the state shown in FIG. 10A from luminance values 0 to 7, the total number of pixels is 2 + 6 + 2 + 5 + 4 + 3 + 2 + 0 = 24, and the luminance values are divided into 8 levels. When the total number of pixels is divided by 8, 3 is obtained as the number of pixels assigned to one luminance value. Three pixels are taken out from the higher luminance of the pseudo monochrome image (luminance value 7), and are newly assigned from the luminance value 7 so that the number of pixels of each luminance value becomes 3, as shown in FIG. In this way, by assigning pixels from where the number of pixels is large to where the number is small, the number of pixels for each luminance value is made equal, and the contrast is enhanced.
[0041]
FIG. 11 shows a comparison of the luminance distribution of the same region before and after the contrast enhancement processing of the luminance distribution between the projected pixels of the B-color projection image projected on the white material panel 6a on the screen 2, and the contrast enhancement processing. Thus, it can be seen that the brightness difference between the bright portion of the projection pixel and the dark portion which is the separation of the projection pixel is increased, and the contrast is enhanced. In FIG. 11, the vicinity of X-coordinates 23 to 27 corresponds to a dark part that becomes a break between projection pixels.
[0042]
Next, a focus inspection area is set by the focus inspection area generation unit 18 (step A8).
FIG. 12 is a diagram showing the positional relationship of the focus inspection areas generated by the focus inspection area generation unit shown in FIG.
[0043]
As shown in FIG. 12, the focus inspection area generation unit 18 sets focus inspection areas at four locations of the integrated digital image. The focus inspection area is set so as to correspond to the color CCD cameras 3a, 3b, 3c, and 3d capturing the four corners of the screen. Since the distribution of projection pixels in the integrated digital image is almost constant at any position in the camera field of view, as shown in FIG. 12, the size of the focus inspection area is set to a range where the number of projection pixels is about 3 pixels. ing. This is because the number of pixels necessary for calculation for focus adjustment is minimized to reduce the number of calculations, thereby realizing high speed.
[0044]
Next, the projection processing unit 19 performs luminance integration for each direction in the X direction and the Y direction, which are the light distribution characteristics in the focus inspection area (step A9).
FIG. 13 is a diagram showing the relationship between the distribution of the luminance integration value obtained by the luminance integration by the projection processing unit shown in FIG. 5 and the projection pixel.
[0045]
The projection processing unit 19 performs luminance integration for each direction in the X direction and the Y direction of the focus inspection area set by the focus inspection area generation unit 18. By performing the luminance integration, as shown in FIG. 13, the characteristics of the light amount distribution in the bright part of the projection pixel and the dark part that becomes a break between the projection pixels are clearer than the characteristic of the luminance value distribution shown in FIG. Can be caught.
[0046]
Next, the maximum and minimum luminance integral values in the X and Y directions obtained by the projection processing unit 19 are searched for by the in-area light amount analysis unit 20 (step A10).
[0047]
The in-area light quantity analysis unit 20 includes a maximum value PXmax in the X-direction integrated luminance value, a minimum X-direction integrated luminance value PXmin, and a maximum Y-directional integrated luminance value in the focus inspection area shown in FIG. PYmax and the minimum value PYmin of luminance integrated values in the Y direction are searched.
[0048]
Next, the contrast sensitivity calculation unit 21 calculates the value corresponding to the image sharpness as the contrast sensitivity from the maximum and minimum luminance integrated values in the X and Y directions searched by the in-area light quantity analysis unit 20, and (Step A11), a focus position at which the image is clearest is obtained from the calculated contrast sensitivity (step A12).
[0049]
The contrast sensitivity calculation unit 21 first calculates the contrast Cx in the X direction and the contrast Cy in the Y direction in each focus inspection area. Cx and Cy are
Cx = (PXmax−PXmin) / (PXmax + PXmin)
Cy = (PYmax−PYmin) / (PYmax + PYmin)
(In fact, there are ½ in the numerator and denominator, but they are omitted).
[0050]
The numerators of the contrasts Cx and Cy in the X direction and the Y direction indicate the amount of change in the light amount of the projected image pattern by halving the difference between the maximum value and the minimum value of the luminance integral value, and the contrast in the X direction and the Y direction. The denominator of Cx and Cy is the sum of the maximum value and the minimum value of the luminance integral value, and represents the average light amount of the projected video pattern. Therefore, the contrasts Cx and Cy in the X direction and the Y direction represent the ratio of the amount of change in the light quantity of the projected video pattern to the average light quantity of the projected video pattern.
[0051]
The contrast sensitivity calculation unit 21 calculates the X-direction contrast sensitivity Sx and the Y-direction contrast sensitivity Sy in each focus inspection area based on Cx and Cy. Sx and Sy are reciprocals of Cx and Cy,
Sx = 1 / Cx
Sy = 1 / Cy
Can be expressed as
[0052]
The contrast sensitivity calculation unit 21 calculates the contrast sensitivity S (z) in each focus inspection area based on Sx and Sy. S (z) is an average value of Sx and Sy,
S (z) = (Sx + Sy) / 2
Can be expressed as
[0053]
The processing from step A3 to step A11 is performed while the liquid crystal panel 9a is moved stepwise within the optical axis movement range in the Z-axis direction by the optical axis adjustment mechanism unit 8, and the contrast sensitivity calculation unit 21 calculates the calculated contrast sensitivity S. (Z) is stored in association with the Z-axis position at the time of calculation.
[0054]
Next, a focus position is obtained from the contrast sensitivity calculated for each focus inspection area by the contrast sensitivity calculation unit 21 by the contrast search unit 22 (step A12).
[0055]
The contrast search unit 22 obtains, as the focus position, the Z-axis position where the contrast sensitivity S (z) calculated for each focus inspection area is minimized. The focus positions for each focus inspection area (upper left, upper right, lower left, lower right) are obtained as Za, Zb, Zc, and Zd, respectively. Za, Zb, Zc, Zd are
Za = min {S (z)}
Zb = min {S (z)}
Zc = min {S (z)}
Zd = min {S (z)}
Can be expressed as
[0056]
The reason why the Z-axis position where the contrast sensitivity S (z) is the minimum value is the focus position will be described.
FIG. 14 is a diagram showing a change in the luminance integrated value in the X direction obtained by integrating the luminance by the projection processing unit shown in FIG. 5 when the Z axis is moved at an interval of 10 μm, and FIG. FIG. 16 is a diagram showing the relationship between the maximum and minimum values of the luminance integration values integrated by the projection processing unit shown in FIG. 5 and the Z-axis position when the Z-axis is moved at intervals of 10 μm and imaged. FIG. 6 is a diagram showing a relationship between a value obtained by subtracting a minimum value from a maximum value of luminance integration values integrated by the projection processing unit shown in FIG. 4 and a Z-axis position when an image is taken while moving the Z-axis at intervals of 10 μm. 17 is an explanatory diagram for explaining the tendency of change when the Z-axis of the luminance integrated value in the X and Y directions integrated by the projection processing unit shown in FIG. 5 is moved and imaged, and FIG. The contrast sensitivity calculated by the contrast sensitivity calculator shown in FIG. 5 and the Z axis Is a diagram showing the relationship between the location.
[0057]
FIG. 14 shows the X direction in which the luminance is integrated by the projection processing unit 19 when the liquid crystal panel 9c in charge of the B color is moved in the Z axis direction at intervals of 10 μm in the + − direction centered on the focus position. The integrated luminance values are plotted. Referring to FIG. 14, it can be seen that the plotted values have a width, and by moving the liquid crystal panel 9c in the Z-axis direction, the maximum luminance integrated value PXmax in the X direction and the minimum luminance integrated value in the X direction are detected. It can be seen that the value PXmin has changed. Further, by moving the liquid crystal panel 9c in the Z-axis direction, the maximum value PYmax of the luminance integrated value in the Y direction and the minimum value PYmin of the luminance integrated value in the Y direction also change.
[0058]
The changes in PXmax and PXmin caused by moving the liquid crystal panel 9c in the Z-axis direction and the changes in PYmax and PYmin have opposite properties. That is, as shown in FIG. 15, PXmax decreases when the liquid crystal panel 9c is sequentially moved along the Z axis from the front (− direction) across the focus position to the dichroic prism 10 direction (+ direction). PYmax increases, PXmin increases, and PYmin decreases.
[0059]
Therefore, when the liquid crystal panel 9c is sequentially moved along the Z axis from the front (− direction) across the focus position to the dichroic prism 10 direction (+ direction), as shown in FIG. 16, (PXmax−PXmin ) Decreases, the light amount change amount (PYmax−PYmin) of the projected image pattern in the Y direction increases, and (PXmax + PXmin) and (PYmax + PYmin) hardly change.
[0060]
That is, when the liquid crystal panel 9c is sequentially moved along the Z axis from the front (− direction) to the dichroic prism 10 direction (+ direction) across the focus position, as shown in FIG. The amount of change in the light quantity of the projected image pattern in the X direction, which is the difference between the maximum value and the minimum value of the integral value, is reduced, and the projected image in the Y direction, which is the difference between the maximum value and the minimum value of the luminance integrated value in the Y direction. The amount of change in the amount of light in the pattern is enlarged, and the nature of the amount of change in the amount of light in the projected video pattern is contradictory between the X direction and the Y direction.
[0061]
Accordingly, changes in contrast sensitivity Sx and Sy when the liquid crystal panel 9c is sequentially moved along the Z axis from the front (− direction) to the dichroic prism 10 direction (+ direction) across the focus position are shown in FIG. As described above, Sx increases, Sy decreases, and Sx and Sy have a contradictory property at the focus position. Contrast sensitivity S (z) that is an average value of Sx and Sy is shown in FIG. As shown by the center curve, the minimum value is at the focus position where the projected image is clearest.
[0062]
Next, the optical axis control unit 15 generates a command value for the optical axis adjustment mechanism unit 8 based on the focus position of each focus inspection area (step A13).
19 is a diagram showing a positional relationship between the liquid crystal panel adjusted by the optical axis adjustment mechanism unit shown in FIG. 5 and the optical axis coordinate system, and FIG. 20 is a liquid crystal adjusted by the optical axis adjustment mechanism unit shown in FIG. FIG. 21 is a view of the positional relationship between the panel and the optical axis coordinate system as viewed from above the X axis. FIG. 21 shows the positional relationship between the liquid crystal panel adjusted by the optical axis adjusting mechanism shown in FIG. It is the figure seen from the axis | shaft upper side.
[0063]
Since the liquid crystal panel 9a has rotation, tilt, and tilt angles in the X and Y directions with respect to the optical axis direction of the Z axis, and there is a difference in the optical path length to the projection surface, each focus inspection area (upper left, upper right, The focus positions Za, Zb, Zc, and Zd obtained from the color images obtained by imaging the lower left and lower right) with the color CCD cameras 3a, 3b, 3c, and 3d, respectively, do not match. Accordingly, if the true focus surface position through which the center of the liquid crystal panel 9a passes is found from the focus positions Za, Zb, Zc, and Zd, the final focus position of the liquid crystal panel can be searched.
[0064]
FIG. 19 shows the positional relationship between the liquid crystal panel 9a and the optical axis coordinate system having the origin at the center of the liquid crystal panel 9a. FIG. 19 shows the Z axis, and FIG. FIG. 21 shows the positional relationship when viewed from the upper side of the Y-axis, and the actual liquid crystal panel is tilted with respect to other optical axes other than the Z-axis direction, the Xθ direction, the Yθ direction, and θ. Is shown.
[0065]
From the geometric relationship between the optical axis position and the liquid crystal panel 9a shown in FIGS. 19, 20, and 21, the focus plane of the liquid crystal panel 9a is a position where the focus planes of the four focus inspection areas in the Z-axis direction intersect. This is equal to the focus gravity center calculated from the focus position in each focus inspection area.
[0066]
Therefore, the true focus position Z of the optical axis (Z axis) perpendicular to the screen 2 of the liquid crystal panel 9a is
Z = {Za + Zb + Zc + Zd} / 4
Is calculated.
[0067]
Also, assuming that the vertical and horizontal lengths of the liquid crystal panel 9a are Lh and Lv, respectively, the adjustment correction amounts θx and θy in the rotation direction of the Xθ and Yθ axes are based on the positional relationship between the vertex of the liquid crystal panel and the optical axis.
θx = sin^-1({(Za + Zb)-(Zc + Zd)} / 2Lh)
θy = sin^-1({(Za + Zc)-(Zb + Zd)} / 2Lv)
By moving the optical axes of θx and θy so as to cancel the tilt angle of the focus plane, the liquid crystal panel 9a and the adjustment optical axis can be adjusted without adjusting the focus on the optical axes of Xθ and Yθ. The focus plane of the liquid crystal panel 9a can be determined from the geometric relationship and the focus position of each focus inspection area of the projected image.
[0068]
The contrast search unit 22 generates the true focus position Z and the adjustment correction amounts θx and θy in the rotation direction of the Xθ and Yθ axes as command values to the optical axis adjustment mechanism unit 8, and the optical axis adjustment mechanism unit 8 Then, the optical axis of the liquid crystal panel 9a is adjusted based on the command value from the contrast search unit 22 (step A14). If there is no problem in other alignment, the liquid crystal panel 9a is fixed to the dichroic prism 10 by soldering or the like. Is done.
[0069]
The processing from step A1 to step A14 is performed for each of the liquid crystal panels 9a, 9b, 9c, and the focus adjustment of all the liquid crystal panels 9a, 9b, 9c attached to the dichroic prism 10 is performed.
[0070]
FIG. 22 is a diagram illustrating an example of shortening the adjustment time by adjustment based on the command value generated by the contrast search unit illustrated in FIG.
A command value (one-axis high-speed adjustment using a geometric relationship) generated by the contrast search unit when comparing the adjustment time when performing the focus adjustment of the projected images of all the R, G, and B colors ) And the adjustment time when individual adjustment is performed for each axis (3-axis individual adjustment), as shown in FIG. It can be seen that the time is improved by about 2.5 times compared to the adjustment time.
[0071]
As described above, according to the present embodiment, the pseudo monochrome image generation unit 16 uses the luminance value of the integrated digital image data of each color component stored in the image memory 13 for each color component on the projection surface. A pseudo-monochrome image, which is a grayscale image close to the light intensity of the image, is generated, and the image captured in a single color can be treated as luminance information irrelevant to the color of the projected image, so the difference in visibility between the camera sensitivity and the naked eye Regardless of the effect, the brightness setting of the image captured by the camera can be set appropriately, and the optical axis position can be accurately adjusted to the focus position where the focus of the projected image is clear by performing automatic focus adjustment Play.
[0072]
Furthermore, according to the present embodiment, the contrast image generation unit 17 obtains the luminance distribution state of the pseudo monochrome image, creates a histogram for each luminance value, and performs luminance conversion so that the number of pixels of each luminance value becomes equal. By applying this, the brightness distribution feature is enhanced while inheriting the light intensity distribution feature on the projection surface, and the difference in pixel brightness between the bright and dark portions of the projected image is increased, thereby increasing the contrast. Since the original nature of the luminance dispersion of the projected pixels is clarified and the focus is adjusted automatically even in the case of blue with extremely low visibility, the projected pixel area of the projected image is There is an effect that the optical axis position can be accurately adjusted to the focus position where the sharpness is the best.
[0073]
Furthermore, according to the present embodiment, the projection processing unit 19 performs luminance integration for each direction in the X direction and the Y direction, which are the light distribution characteristics in the focus inspection area, so that the projection pixel area for each direction is covered. Since it can be expressed as a characteristic variation of a sine wave shape that emphasizes the luminance distribution on the projection plane, automatic focus adjustment that takes into account blurring in the vertical (Y) and horizontal (X) directions of the projection pixels of the projected image Can be performed, and is not easily affected by pixel shape fluctuations of individual projection pixels along the optical axis, flare generated between projection pixels, or image noise, and can take universal features at any position in the projected image There is an effect that the optical axis position can be accurately adjusted to the focus position where the sharpness of the projected pixel area of the projected video is the best.
[0074]
Furthermore, according to the present embodiment, the contrast sensitivities Sx and Sy in the X and Y directions are obtained from the maximum and minimum values of the integrated luminance value that emphasizes the luminance distribution on the screen 2, and the contrast sensitivities Sx and Sy are obtained. Since the optical axis position at which the contrast sensitivity S (z), which is the average value of the sums, is the minimum value is obtained as the focus position, the movement of the optical axis position in the Z direction, which is the normal direction of the liquid crystal panels 9a, 9b, 9c. Thus, it is possible to unify the handling of characteristics with different degrees of projection pixel blurring in the X and Y directions, and to accurately adjust the optical axis position to the focus position where the focus of the projected image is clear.
[0075]
Furthermore, according to the present embodiment, the projected images projected on the white material panels 6a, 6b, 6c, 6d such as photo printing paper and standard white board with a small surface roughness stretched on the screen 2 are picked up. Therefore, the projection image reflecting the original optical characteristics of the liquid crystal projector 1 can be taken without being affected by the irregular reflection of the light due to the unevenness of the screen and the reflected light of the outside light, and the focus of the entire projection image is the clearest. The optical axis position can be accurately adjusted to the focus position.
[0076]
In the present embodiment, the projected images are captured by the color CCD cameras 3a, 3b, 3c, and 3d arranged at the four corners of the projected image, and the focus position for each imaging location is obtained. As long as the deviation of the tilt angle Xθ and the tilt angle Vθ in the Y-axis direction is not a problem, the number of imaged locations may be reduced to one location in the center of the projected image.
[0077]
Further, in the present embodiment, focus adjustment is performed by obtaining a focus position based on an image obtained by capturing a projected image projected on the screen 2, but for focus inspection from an image before being projected on the screen 2. You may make it obtain the image of. In order to obtain an image for focus inspection from an image before being projected on the screen 2, the projection light may be dispersed in the liquid crystal projector 1, and the dispersed projection light may be received by a photoelectric converter or the like.
[0078]
In this way, an image for focus inspection can be obtained in the liquid crystal projector 1, and the A / D conversion circuit 11, the digital image integrator 12, the image memory 13, the image recognition processing unit 14, the optical axis control of the present embodiment. When the unit 15 and the optical axis adjustment mechanism unit 8 are provided in the liquid crystal projector 1, not only focus adjustment in the manufacturing process but also focus adjustment after assembling as a product can be performed.
[0079]
Further, in the present embodiment, the position adjustment of the liquid crystal panel of the optical system of the projection display apparatus has been described. However, the DMD (digital) in a DLP projector in which the liquid crystal panel is replaced with an optical device using a DMD (digital mirror device). It is also effective for adjusting the projected image by adjusting the position of the mirror device.
[0080]
Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.
[0081]
【The invention's effect】
The focus adjustment apparatus and focus adjustment method of the present invention generates a pseudo monochrome image that is a grayscale image close to the light intensity on the projection surface using the luminance value of the integrated digital image data of each color component stored for each color component. However, since the image captured in a single color can be handled as luminance information that is not related to the color of the projected image, the brightness setting of the image captured by the camera can be set appropriately regardless of the difference in visibility between the camera sensitivity and the naked eye. And by adjusting the focus automatically, the optical axis position can be accurately adjusted to the focus position where the focus of the projected video is clear.
[0082]
Furthermore, the focus adjustment apparatus and the focus adjustment method of the present invention calculate the luminance distribution state of the pseudo monochrome image, create a histogram for each luminance value, and perform luminance conversion so that the number of pixels of each luminance value becomes equal. In this way, the brightness distribution feature is emphasized while inheriting the light intensity distribution feature on the projection surface, and the brightness difference between the bright and dark portions of the projected image is increased to increase the contrast and sharpen the image. Therefore, by clarifying the original nature of the luminance dispersion of the projected pixels and automatically adjusting the focus even in the case of blue, which is extremely poor in visibility, the sharpness of the projected pixel area of the projected image can be obtained. There is an effect that it is possible to accurately match the optical position of the focus position at which is best.
[0083]
Furthermore, the focus adjustment apparatus and the focus adjustment method of the present invention perform the luminance integration for each direction in the X direction and the Y direction, which are the light distribution characteristics in the focus inspection area, thereby projecting the projection pixel area for each direction. Since it can be expressed as a characteristic variation of a sinusoidal shape with emphasis on the luminance distribution on the surface, the focus is automatically adjusted in consideration of blurring in the vertical (Y) direction and the horizontal (X) direction of the projection pixel of the projected image. It is difficult to be affected by pixel shape variation of individual projection pixels along with the optical axis, flare generated between projection pixels, and image noise, and can take universal features regardless of the position of the projected image, There is an effect that the optical axis position can be accurately adjusted to the focus position where the sharpness of the projected pixel area of the projected video is the best.
[0084]
Furthermore, the focus adjustment apparatus and the focus adjustment method of the present invention obtain the contrast sensitivities Sx and Sy in the X and Y directions from the maximum and minimum values of the integrated luminance value that emphasizes the luminance distribution on the screen, and the contrast sensitivity Sx. In order to obtain the optical axis position at which the contrast sensitivity S (z), which is the average value of the sum of Sy, becomes the minimum value, as the focus position, the optical axis position movement in the Z direction, which is the normal direction of the liquid crystal panel, Thus, the characteristic that the degree of blur of the projection pixel differs in the Y direction can be handled in an integrated manner, and the optical axis position can be accurately adjusted to the focus position where the focus of the projected image is clear.
[0085]
Furthermore, the focus adjustment apparatus and the focus adjustment method of the present invention capture a projected image projected on a white material panel such as a photo print paper or a standard white board with a small surface roughness stretched on the screen. A projection image reflecting the original optical characteristics of a liquid crystal projector can be captured without being affected by irregular reflection of light due to unevenness or reflected light from outside light, and the light at the focus position where the focus of the entire projection image becomes clearest. There is an effect that the axial position can be accurately adjusted.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a focus adjustment apparatus according to the present invention.
2 is a plan view showing the positional relationship of the color CCD camera shown in FIG. 1. FIG.
3 is a side view showing the positional relationship of the color CCD camera shown in FIG.
4 is a diagram showing an imaging position on a screen by the color CCD camera shown in FIG. 1. FIG.
5 is a block diagram illustrating a configuration of an image recognition processing unit illustrated in FIG. 1. FIG.
6 is a diagram showing a positional relationship between an adjustment optical axis of an optical component of a liquid crystal projector moved by the optical axis adjustment mechanism unit shown in FIG. 1 and a liquid crystal panel for each color. FIG.
FIG. 7 is a flowchart for explaining the operation of the embodiment of the focus adjustment apparatus according to the present invention.
FIG. 8 is a diagram illustrating an example of integrated digital image data generated by the digital image integrator shown in FIG. 5;
9 is a histogram of the number of pixels for each luminance value for explaining the contrast enhancement processing by the contrast image generation unit shown in FIG.
10 is an explanatory diagram for explaining an algorithm for contrast enhancement processing by the contrast image generation unit shown in FIG. 5; FIG.
11 is a graph for comparing luminance distributions in the same region before and after contrast enhancement processing by the contrast image generation unit shown in FIG. 5;
12 is a diagram showing a positional relationship of focus inspection areas generated by a focus inspection area generation unit shown in FIG.
13 is a diagram showing a relationship between a distribution of luminance integration values obtained by luminance integration by the projection processing unit shown in FIG. 5 and projection pixels.
14 is a diagram showing a change in a luminance integrated value in the X direction obtained by integrating the luminance by the projection processing unit shown in FIG. 5 when an image is taken while moving the Z axis at intervals of 10 μm.
15 is a diagram showing the relationship between the maximum and minimum values of the luminance integrated value integrated by the projection processing unit shown in FIG. 5 and the Z-axis position when the Z-axis is moved at intervals of 10 μm and imaged. FIG. .
16 shows the relationship between the value obtained by subtracting the minimum value from the maximum value of the luminance integrated value integrated by the projection processing unit shown in FIG. 5 and the Z-axis position when the Z-axis is moved at intervals of 10 μm and imaged. FIG.
17 is an explanatory diagram for explaining a tendency of a change when the Z-axis of the luminance integrated value in the X and Y directions integrated by the projection processing unit shown in FIG. 5 is moved and imaged. FIG.
18 is a diagram showing the relationship between the contrast sensitivity calculated by the contrast sensitivity calculation unit shown in FIG. 5 and the Z-axis position.
19 is a diagram showing the positional relationship between the liquid crystal panel adjusted by the optical axis adjustment mechanism shown in FIG. 5 and the optical axis coordinate system.
20 is a view of the positional relationship between the liquid crystal panel and the optical axis coordinate system adjusted by the optical axis adjustment mechanism shown in FIG. 5, as viewed from the upper side of the X axis.
21 is a view of the positional relationship between the liquid crystal panel and the optical axis coordinate system adjusted by the optical axis adjustment mechanism unit shown in FIG. 5, as viewed from the upper side of the Y axis.
22 is a diagram showing an example of shortening the adjustment time by adjustment based on the command value generated by the contrast search unit shown in FIG.
[Explanation of symbols]
1 LCD projector
2 screens
3a, 3b, 3c, 3d color CCD camera
4 Video signal generator
5 Black curtain tent
6a, 6b, 6c, 6d White material panel
7 Recognition control unit
8 Optical axis adjustment mechanism
9a, 9b, 9c LCD panel
10 Dichroic prism
11 A / D conversion circuit
12 Digital image integrator
13 Image memory
14 Image recognition processor
15 Optical axis controller
16 Pseudo monochrome image generator
17 Contrast image generator
18 Focus inspection area generator
19 Projection processing unit
20 Area light quantity analysis
21 Contrast sensitivity calculator
22 Contrast search part

Claims (28)

A focus adjustment device that adjusts an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel,
Imaging means for imaging the video as an image while moving the optical axis position in the normal direction of the liquid crystal panel;
A pseudo monochrome image generating means for generating a pseudo monochrome image from the image picked up by the image pickup means;
Focus search means for searching for the optical axis position based on the luminance distribution of the pseudo monochrome image generated by the pseudo monochrome image generation means;
An optical axis adjustment mechanism means for moving the liquid crystal panel to the optical axis position searched by the focus search means. The pseudo monochrome image generation means has a luminance distribution I of the pseudo monochrome image, and luminance distributions of color components of the image are R, G, and B, respectively.
I = (28 * R + 77 * G + 151 * B) / 256
The focus adjustment apparatus according to claim 1, wherein the pseudo monochrome image is generated. Contrast enhancement means for enhancing the contrast of the pseudo monochrome image,
3. The focus adjustment apparatus according to claim 1, wherein the focus search unit searches the optical axis position based on a luminance distribution of the pseudo monochrome image whose contrast is enhanced by the contrast enhancement unit.   4. The focus adjustment apparatus according to claim 3, wherein the contrast enhancement unit averages the number of pixels in each luminance value of the pseudo monochrome image. Projection processing means for performing luminance integration for each direction in the X direction and Y direction of the pseudo monochrome image,
5. The focus according to claim 1, wherein the focus searching unit searches the optical axis position based on the pseudo monochrome image obtained by integrating the luminance in the X and Y directions by the projection processing unit. Adjustment device. The maximum luminance value PXmax in the X direction, the minimum luminance value PXmin in the X direction, and the maximum luminance value in the Y direction of the pseudo monochrome image integrated in the X and Y directions by the projection processing unit. A light amount analyzing means for searching for the PYmax and the minimum value PYmin of the luminance integral value in the Y direction for each optical axis position in the normal direction of the moved liquid crystal panel;
6. The focus adjustment apparatus according to claim 5, wherein the focus search means searches for the optical axis position based on PXmax, PXmin, PYmax and PYmin searched by the light amount analysis means. Contrast sensitivity calculation means for calculating contrast sensitivity Sx, Sy for each of the X and Y directions from PXmax, PXmin, PYmax and PYmin searched by the light amount analysis means,
  The focus adjustment apparatus according to claim 6, wherein the focus search unit searches for an optical axis position based on the contrast sensitivities Sx and Sy calculated by the contrast sensitivity calculation unit. The contrast sensitivity calculation means calculates the contrast sensitivity Sx, Sy.
Cx = (PXmax−PXmin) / (PXmax + PXmin)
Cy = (PYmax−PYmin) / (PYmax + PYmin)
Sx = 1 / Cx
Sy = 1 / Cy
The focus adjustment apparatus according to claim 7, wherein the focus adjustment apparatus is defined and calculated. The focus search means is calculated by the contrast sensitivity calculation means. 9. The focus adjustment apparatus according to claim 8, wherein an optical axis position at which an average value of the sums of the contrast sensitivities Sx and Sy thus output is a minimum value is searched. A focus adjustment device that adjusts an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel,
  Imaging means for imaging the video while moving the optical axis position in the normal direction of the liquid crystal panel;
  The maximum value PXmax of the luminance integrated value in the X direction, the minimum value PXmin of the luminance integrated value in the X direction, the maximum value PYmax of the luminance integrated value in the Y direction, and the minimum of the luminance integrated value in the Y direction of the image captured by the imaging means. A light amount analyzing means for searching for each optical axis position in the normal direction of the liquid crystal panel to which the value PYmin is moved;
  Contrast sensitivity calculating means for calculating contrast sensitivity Sx, Sy for each of the X and Y directions from PXmax, PXmin, PYmax and PYmin searched by the light amount analyzing means;
  Focus search means for searching for an optical axis position based on the contrast sensitivity Sx, Sy calculated by the contrast sensitivity calculation means;
  Optical axis adjustment mechanism means for moving the liquid crystal panel to the optical axis position searched by the focus search means,
  The contrast sensitivity calculation means calculates the contrast sensitivity Sx, Sy.
Cx = (PXmax−PXmin) / (PXmax + PXmin)
Cy = (PYmax−PYmin) / (PYmax + PYmin)
Sx = 1 / Cx
Sy = 1 / Cy
Focus adjustment device characterized in that it is defined and calculated. 11. The focus adjustment apparatus according to claim 10, wherein the focus search unit searches for an optical axis position at which an average value of the sum of the contrast sensitivities Sx and Sy calculated by the contrast sensitivity calculation unit is a minimum value. . The imaging means images four corners of the video,
  The focus adjustment apparatus according to claim 1, wherein the focus search unit searches for optical axis positions at four corners imaged by the imaging unit. Correction values for correcting the optical axis in the normal direction of the liquid crystal panel, the tilt angle Xθ in the X-axis direction, and the tilt angle Vθ in the Y-axis direction are calculated based on the optical axis positions at the four corners searched by the focus search means. 13. The focus adjustment apparatus according to claim 12, further comprising an optical axis control means for performing the operation. The focus adjustment apparatus according to claim 1, wherein the image pickup unit picks up the image projected on a screen on which a white material panel having a small surface roughness is stretched. A focus adjustment method for adjusting an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel,
  Taking the video as an image while moving the optical axis position in the normal direction of the liquid crystal panel,
  Generating a pseudo monochrome image from the image;
  Search the optical axis position based on the luminance distribution of the pseudo monochrome image,
  A focus adjustment method, wherein the liquid crystal panel is moved to an optical axis position searched using an optical axis adjustment mechanism. Luminance distribution of the pseudo monochrome image I And the luminance distribution of the color components of the image is R, G, and B, respectively,
I = (28 * R + 77 * G + 151 * B) / 256
The focus adjustment method according to claim 15, wherein the pseudo monochrome image is generated. Emphasize the contrast of the pseudo monochrome image,
  The focus adjustment method according to claim 15 or 16, wherein an optical axis position is searched based on a luminance distribution of the pseudo monochrome image with the contrast enhanced. 18. The focus adjustment method according to claim 17, wherein the contrast is enhanced by averaging the number of pixels in each luminance value of the pseudo monochrome image. Perform luminance integration for each direction in the X and Y directions of the pseudo monochrome image,
  19. The focus adjustment method according to claim 15, wherein an optical axis position is searched based on the pseudo monochrome image obtained by integrating the luminance in the X and Y directions. The maximum luminance value PXmax in the X direction, the minimum luminance value PXmin in the X direction, the maximum luminance integration value PYmax in the Y direction, and the Y direction in the pseudo monochrome image obtained by integrating the luminance in the X and Y directions. Search for the minimum value PYmin of the luminance integral value for each optical axis position in the normal direction of the moved liquid crystal panel,
  20. The focus adjustment method according to claim 19, wherein the optical axis position is searched based on the searched PXmax, PXmin, PYmax, and PYmin. From the searched PXmax, PXmin, PYmax and PYmin, the contrast sensitivity Sx, Sy is calculated for each of the X and Y directions,
  21. The focus adjustment method according to claim 20, wherein the optical axis position is searched based on the contrast sensitivities Sx and Sy. The contrast sensitivity Sx, Sy
Cx = (PXmax−PXmin) / (PXmax + PXmin)
Cy = (PYmax−PYmin) / (PYmax + PYmin)
Sx = 1 / Cx
Sy = 1 / Cy
The focus adjustment method according to claim 21, wherein the calculation is defined as 23. The focus adjustment method according to claim 22, wherein an optical axis position at which an average value of the calculated sums of the contrast sensitivities Sx and Sy is a minimum value is searched. A focus adjustment method for adjusting an optical axis position of the liquid crystal panel based on an image passed through the liquid crystal panel,
  Taking the video while moving the optical axis position in the normal direction of the liquid crystal panel,
  The maximum value PXmax of the luminance integral value in the X direction, the minimum value PXmin of the luminance integral value in the X direction, the maximum value PYmax of the luminance integral value in the Y direction, and the minimum value PYmin of the luminance integral value in the Y direction of the captured image. Search for each optical axis position in the normal direction of the moved liquid crystal panel,
From the searched PXmax, PXmin, PYmax and PYmin, the contrast sensitivities Sx and Sy are set for the X and Y directions.
Cx = (PXmax−PXmin) / (PXmax + PXmin)
Cy = (PYmax−PYmin) / (PYmax + PYmin)
Sx = 1 / Cx
Sy = 1 / Cy
And define
Search the optical axis position based on the calculated contrast sensitivity Sx, Sy,
  A focus adjustment method, wherein the liquid crystal panel is moved to an optical axis position searched using an optical axis adjustment mechanism. 25. The focus adjustment method according to claim 24, wherein an optical axis position at which an average value of the calculated sums of the contrast sensitivities Sx and Sy is a minimum value is searched . Capture four corners of the video,
  The focus adjustment method according to any one of claims 15 to 25, wherein the four optical axis positions of the imaged corners are searched for. Correction values for correcting the optical axis in the normal direction of the liquid crystal panel, the tilt angle Xθ in the X-axis direction, and the tilt angle Vθ in the Y-axis direction are calculated based on the searched optical axis positions at the four corners. The focus adjustment method according to claim 26. The focus adjustment method according to any one of claims 15 to 27, wherein the image projected on a screen on which a white material panel having a small surface roughness is stretched is captured.

Images