JP2013021674A - Image measuring method, image measuring device and image inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image measuring method for calibrating a photographing device with a correction value of a distortion component of an optical characteristic in the photographing device and highly precisely measuring the optical characteristic in a projected image of a projector.SOLUTION: The projector illuminates a calibration pattern formed of a prescribed pattern with black and white with monochromatic light (S101). The photographing device photographs the calibration pattern on a calibration face (S102), and an image processor analyzes a position of the calibration pattern in response to an image signal outputted from the photographing device (S103). A correction value of the distortion component of the optical characteristic of the photographing device is calculated from a relative relation between the actual analyzed position of the calibration pattern and an ideal position of the calibration pattern (S104). The image signal obtained from the image projected by the projector which is a measurement object is corrected with the correction value (S109), and the optical characteristic of the projected image is measured on the basis of the corrected image signal (S110).

Description

  The present invention relates to an image measurement method, an image measurement apparatus, and an image inspection apparatus for measuring optical characteristics of a projection image projected on a screen from a projector.

  The projector projects a light image created by modulating a light beam emitted from a light source according to image information on a screen. If the screen is a reflective screen, the projected image can be observed from the front side of the screen, and if the screen is a transmissive screen, the projected image can be observed from the back side of the screen.

  A characteristic that determines the quality of the projection image of the projector is distortion of the projection image. As shown in FIG. 12, the distortion of the projection image is compared with the shape of an ideal projection image 101 (virtual image indicated by a broken line in the figure) created from a projector based on image information of, for example, a lattice projection pattern. In other words, the actual projected image 103 projected on the screen 102 (shown by a solid line in the figure) has a different shape. The cause of the distortion of the projection image is related to the configuration of the projector in addition to the projection environment such as the unevenness of the surface of the screen 102.

  The relationship between the configuration of the projector and the distortion of the projected image will be described below with reference to the drawings. FIG. 13 is a schematic perspective view showing the configuration of a projector to be measured. In the projector 200 shown in the figure, the light emitted from the light source 201 reaches the optical image forming panel 202, and the reached light is reflected by the panel arranged in the pixel unit of the optical image forming panel 202 according to the image information. Or is transmitted, and is modulated into projection light of a dot image in units of pixels. The projection light of the dot image is projected onto the screen 204 through the projection lens 203. In the projector 200 having such components, the projected image is distorted due to the mutual installation accuracy between these components, the optical accuracy of the projection lens, the attitude accuracy of each component, and the like. In particular, in a short focus type projector in which the distance from the projector to the screen is shortened, a projection image projected from the projector is projected onto an aspherical mirror or the like, and the reflected light is projected onto the screen. Even a slight error in the shape accuracy and installation accuracy of the aspherical mirror itself causes a large distortion in the projected image.

  Some projectors are called liquid crystal three-plate projectors, and project full color images created by combining projected images separated into RGB colors. In the liquid crystal three-plate projector 300 shown in FIG. 14, the light emitted from the light source 301 is decomposed into three optical paths by the dichroic mirrors 302 and 303 and the mirrors 304 to 306. The decomposed light becomes dot image light for each color by the RGB optical image forming panels 307 to 309 according to the image information. The three color separation dot image lights are combined by the cross prism 310 and projected onto a screen (not shown) via a projection lens unit 311 composed of a plurality of lenses. In the combined projected image of the projector, a phenomenon of color misregistration occurs due to an installation shift between the constituent members in the optical system and a shift between each optical system of each color image. For example, the black color of the character shown in FIG. 15A is a synthesized color of light of all basic colors of RGB. When characters created based on the RGB color signals shown in FIG. 15B are combined, a color shift as shown in FIG. 15C occurs due to a shift between the optical systems of the color images.

  As a method for adjusting the distortion and color misalignment of the projected image in such a projector, the method described in Patent Document 1 is known. In the adjustment method of Patent Document 1, a projection image created based on image information of a calibration pattern is projected from a projector onto a screen, the projection image is photographed by a photographing device, the photographed image is analyzed, and the projected image is analyzed. The correction value is obtained to adjust the distortion and color misalignment of the projected image. This correction amount is a correction value for correcting the distortion and color misalignment of the projected image caused by both the configuration of the projector and the distortion component of the optical characteristics of the photographing apparatus. In order to adjust the color misregistration of the projected image with high accuracy, it is necessary to capture a dot image in pixel units to ensure the resolution. For this reason, the photographing apparatus is enlarged as close as possible to the screen side. However, it is not possible to measure the distortion of the projected image only by enlarging a part of the screen and shooting in a limited shooting range depending on the scale of the distortion. For example, if the projected image is distorted gently over a wide range of the screen, the distortion of the projected image cannot be measured only by photographing a part of the screen. Therefore, in order to measure the distortion of the projected image over such a wide range, there is a method of photographing the calibration pattern chart for each measurement location by dividing the measurement location on the screen into a plurality. The method has a problem that the number of steps increases. In order to solve this problem, the adjustment method disclosed in Patent Document 1 can measure the distortion of a projected image over a wide range by shooting a large shooting range at a high resolution by mounting a high-resolution imaging device on the shooting device. Therefore, according to the adjustment method of Patent Document 1, it is possible to measure the color misregistration at a plurality of points on the screen with a small number of photographing devices, so that it is possible to measure images at low cost and at high speed.

  However, in the method of adjusting distortion and color misalignment of the projected image described in Patent Document 1, when shooting a wide range of the screen with one shooting device, the image signal itself is caused by the aberration of the lens mounted on the shooting device. The distortion component signal of the projected image may be included. Lens aberrations include distortion, spherical aberration, coma, astigmatism, and chromatic aberration. In particular, images are distorted due to coma. In addition, the phenomenon that the distortion varies depending on the spectral characteristics of the image light to be photographed becomes a large error when the distortion is calculated by measuring the projection image of the projector. Further, in the measurement of the projection image of the projector, since the spectral characteristics of the light emitted by each projector are not all the same, even if the position of the photographing device is adjusted for each projector, there is aberration of the lens for each projector. Measurement errors due to aberrations cannot be improved.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image measurement method, an image measurement apparatus, and an image inspection apparatus that can accurately measure optical characteristics in a projection image of a projector. is there.

  In order to achieve the above object, according to the first aspect of the present invention, an optical image created by modulating a light beam irradiated from a light source according to image information is projected on a screen by a projector to be measured, and the projected image is projected. An image capturing device that captures an image, and an image processing device that analyzes an image signal output from the image capturing device and calculates a distortion component of the optical characteristics of the projected image. The image signal output from the image capturing device An image measuring apparatus for measuring optical characteristics of a projection image based on a calibration surface member having a calibration surface of a calibration pattern formed in a black and white and a predetermined pattern by the projector with a monochromatic light The calibration pattern of the calibration surface is photographed by the photographing device, and the calibration pattern is based on an image signal output from the photographing device by the image processing device. A correction value for a distortion component of the optical characteristics of the photographing apparatus is calculated from the relative relationship between the actual position of the calibration pattern thus analyzed and the position of the ideal calibration pattern. A projection image generated based on the image information of the measurement pattern is projected onto a screen, the projection image is captured by the imaging device, and an image signal output from the imaging device is calculated based on the calculated optical characteristics of the imaging device. The optical characteristic of the projection image is measured based on the corrected image signal, corrected by the distortion component correction value.

  In the present invention, a calibration surface member having a calibration surface of a calibration pattern is irradiated using a measurement projector as illumination, and the calibration pattern is photographed by the photographing apparatus. Then, the correction value of the distortion component of the optical characteristic of the photographing apparatus is calculated in advance by the image processing means. By using this correction value to correct the image signal obtained by photographing the projection image of the measurement target projector obtained by image measurement with the photographing device, the photographing device has a distortion component of optical characteristics. However, the distortion component of the optical characteristics of the photographing apparatus can be eliminated from the image signal obtained from the projection image, and the optical characteristics of the projection image of the projector can be accurately measured.

  As described above, according to the present invention, it is possible to obtain an effect that the optical characteristics in the projected image of the projector can be accurately measured.

It is the schematic which shows the structure of an image measuring device. It is a top view which shows an example of a calibration pattern. It is a top view which shows another example of a calibration pattern. It is a flowchart which shows the distortion inspection process of the projection image of this embodiment. It is a figure which shows the outline | summary of correction | amendment of a projector projection pattern measurement coordinate. It is a figure explaining an example of a correction calculation method. It is a top view which shows the image showing the image distortion state of a projector. It is a flowchart which shows the distortion test process of the projection image in another modification of this embodiment. It is a figure which shows the projection image on the screen at the time of a resist test | inspection. It is a figure which shows the projection image on the screen at the time of an aspect-ratio test | inspection. It is a figure which shows the projection image on the screen at the time of a line bending test | inspection. It is a top view which shows distortion of a projection image. It is a schematic perspective view which shows the structure of the projector of measurement object. It is the schematic which shows the structure of a liquid crystal 3 plate type projector. It is a figure explaining the color shift phenomenon in the projection image of a projector.

Hereinafter, an embodiment of an image measuring device to which the present invention is applied will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram showing the configuration of the image measurement apparatus of the present embodiment. An image measuring apparatus 10 shown in the figure includes a fixing apparatus 11 that fixes and installs a projector 20 to be measured, a screen 12 on which the projector 20 projects an image, and an imaging apparatus that captures a projected image projected on the screen 12. 13, an image analysis unit 14 that analyzes an image signal captured by the imaging device 13, and a calibration surface member 15 on which a predetermined black and white calibration pattern that can be installed immediately before the screen 12 is formed. . The imaging device 13 is a general imaging device equipped with a solid-state imaging device such as a CCD camera. In addition, the image pickup device of the photographing apparatus 13 is monochrome, and need not be a color image pickup device or a three-plate image pickup device. A monochrome imaging device has sensitivity to the entire wavelength band of light, and even with a single plate type, high resolution and low cost can be expected as compared with a color imaging device. As for the calibration pattern formed on the calibration surface member 15, it is assumed that the same pattern is arranged on the calibration surface at equal intervals, and information such as the pattern position is acquired in advance as an actually measured value obtained by precise measurement. In the example of the calibration pattern of the calibration surface member 15 shown in FIG. 2, a grid pattern in which the background color is black and the pattern portion is white is repeatedly formed, and the intersection coordinates are equally spaced. Another example of the calibration pattern shown in FIG. 3 is a round pattern, in which the background color is black and the round part of the pattern portion is white. The same circle pattern is repeatedly formed, and the centers of the circle portions are equally spaced.

Next, the distortion inspection process for the projected image according to the present embodiment will be described with reference to FIG.
First, a first process for correcting aberrations of the photographing apparatus will be described. The first process (steps S101 to S104) does not need to be performed every time without changing the positional relationship between the imaging device 13 and the screen 12 in FIG. 1 and changing the basic color of the projection image from the projector 20. A measurement target projector 20 or a projector of the same model is installed in the fixing device 11. Next, the calibration surface member 15 is installed immediately before the screen 12. Alternatively, the screen 12 may be removed and a calibration surface member may be installed. The screen 12 and the calibration surface member 15 are installed so that there is no problem that the focus position does not match between the optical surface of the screen 12 and the calibration surface of the calibration surface member 15. Next, the basic color uniform image data is illuminated from the projector onto the calibration surface of the calibration surface member 15 (step S101). Further, light from other light sources is prevented from entering. Uniform image data of the basic color is a basic color used for forming the image color of the projector. For example, an RGB three-plate liquid crystal projector emits only R light and completely blocks other G light and B light. Since the calibration surface of the calibration surface member 15 is formed in a monochrome pattern and the illumination light is a basic color of the projector, the light reflected from the screen 12 is reflected only by the white part of the calibration surface of the calibration surface member 15. The reflected light reflects the spectral characteristics of the projector as it is. In this state, the calibration surface of the calibration surface member 15 is imaged using the imaging device 13 of FIG. 1 (step S102). Based on the image signal from the imaging means 13, the image position of the calibration surface of the calibration surface member 15 is analyzed by the image analysis means 14 of FIG. 1, that is, the position coordinates of the calibration point are measured (step S103). Then, by using the actual measurement value of the calibration surface of the calibration surface member 15, the image distortion correction processing data of the imaging device including the chromatic aberration component of the lens of the imaging device 13 in the basic color of the measurement target projector 20 is calculated. (Step S104).

  Here, an outline of correction of the projector projection pattern measurement coordinates using the calibration pattern will be described with reference to FIG. In the figure, the relationship between the coordinates 31 of the detected calibration pattern and the coordinates 32 of the correct calibration pattern virtually calculated from the actually measured values is used to correct the coordinates 34 of the detected projector pattern. The coordinate 33 is corrected. An example of this correction calculation method is shown in FIG. In this correction calculation, the ratio of the distance from each detection point to the lighting pattern position of the projector to the total distance from each detection point of the calibration pattern to the lighting pattern position of the projector is calculated, and the X and Y coordinates of each detection point are calculated. The position coordinates of the projector lighting pattern whose position is corrected are obtained from the difference from the coordinates of the ideal point. As a result of this correction calculation, the detected projector pattern coordinates are projected onto the correct calibration pattern coordinates that are virtually set, so that the distortion component by the photographing apparatus can be corrected. Data of ideal coordinates A ′, B ′, C ′ of each point shown in FIG.

  Next, a description will be given of the second step that is an image distortion inspection in FIG. 4. The projector 20 to be measured in FIG. 1 is installed in the fixing device 11, and the position pattern is displayed from the projector 20 with the basic colors used during calibration. Projection is performed on the screen 12 switched from the calibration surface member (step S106). This position pattern also uses a calibration pattern as shown in FIGS. However, they do not necessarily need to match. Then, the image projected on the screen 12 is photographed by the photographing device 13 (step S107), and the image signal is analyzed by the image analyzing means 14 to calculate the coordinate value of the position pattern (step S108). The coordinate value corrects an error component such as an aberration of the imaging system using the correction data obtained in the first step (step S109). FIG. 7 showing an image representing the image distortion state of the projector shows the projector pattern coordinates 33 detected by the imaging means of FIG. 1 and the projector pattern coordinates 34 corrected by the correction method. ing. The detected coordinate 34 of the projector pattern is a distortion of the image including the lens aberration component of the image pickup means, whereas the pattern coordinate obtained as a result of correcting the distortion is a distortion component of the measurement target projector itself. It becomes only. From these two data, image distortion is inspected by calculating the linearity of the straight line formed by each pattern coordinate and the magnification error formed by the pitch between the straight lines, which is a characteristic amount of the distortion of the image. (Step S110). As described above, the aberration correction of the photographing apparatus used for distortion measurement in the first step can be performed, and the distortion measurement which is the image quality characteristic of the projector can be performed in the second step.

  In the image measuring apparatus as another modification of the present embodiment, the operation performed only with the basic color of the projector is performed for each color image forming color (for RGB, for each RGB) of the projector to be measured. By relatively comparing the position pattern errors in the formed colors, the color shift amount distribution in the entire projection image of the projector is obtained. Specifically, in a three-plate liquid crystal projector, three optical image forming panels for RGB are mounted, and an image is formed on each panel. Therefore, when this embodiment is applied, as shown in FIG. The first process and the second process are performed for each of the three colors B and B (steps S201, S202, and S203), and the position pattern is measured. Then, a color misregistration amount is calculated from each RGB pattern coordinate value (step S204), and the color misregistration amount is inspected (step S205).

Next, an image inspection apparatus for inspecting the quality of a projection image of a projector to be inspected obtained by the above-described image measuring apparatus will be described. This image inspection apparatus is an apparatus that actually projects a lattice pattern, acquires the coordinates of each intersection by the above-described image measurement apparatus, and inspects resist, aspect ratio, line bending, and color misregistration.
First, resist inspection will be described. Here, the resist is the projected image position. The inspection is performed after the projector to be inspected is installed at a specified position. Then, the designated projection size is obtained by performing an operation such as zooming using the zoom function of the projector. The position of the projected image on the screen at this time is a resist. FIG. 9 is a diagram showing a projected image on the screen at the time of resist inspection. The solid line in the figure is the inspection projection pattern 41 projected on the screen 40, and the dotted line is the ideal projection pattern 42. An ideal coordinate value with respect to the projection pattern designated position with respect to the origin of the calibration plane is set in advance, and the inspection is performed from the difference from the coordinate value of the actual projection image. Then, the resist is inspected by determining whether or not the difference (ΔX, ΔY) between the inspection target position 43 and the ideal projection pattern is equal to or less than the specified standard value.

  Next, the aspect ratio inspection will be described. Here, the aspect ratio is the aspect ratio of the projected image. The projector to be inspected has a design value of the aspect ratio of the projected image. If the aspect ratio is greater than the tolerance for this design value, for example, the aspect ratio of the projected character is different from the design value. For example, it becomes a crushed character. Therefore, in the aspect ratio inspection, as shown in FIG. 10, the vertical (= LY) and horizontal (= LX) dimensions of the projection pattern to be inspected projected on the screen 40 are measured. And then. The aspect ratio is inspected by calculating the aspect ratio R = LY / LX and comparing it with the design value tolerance.

  Next, the inspection of line bending will be described. In a projected image, a pattern that is originally a straight line may be projected in a bent state. In particular, in a short focus projector or the like equipped with an aspheric lens or a mirror, the projected image may be deformed depending on the component accuracy and assembly accuracy. Therefore, in the inspection of the line bending, as shown in FIG. 11, the inspection is performed on arbitrary lines or all lines of each line formed by the lattice pattern. Then, an index indicating how much the line that is originally a straight line is bent is obtained. Specifically, as shown in FIG. 11, based on each intersection coordinate of the grid pattern forming one line, the distance in the vertical direction with respect to a straight line formed by the start point and the end point is set as the intersection point. Calculate for each coordinate. Among them, the maximum values on the + side and the − side are obtained, and the difference is used as an index (bending amount). A line bend is inspected by comparing the bend amount with a standard value.

  Next, color misregistration inspection will be described. As shown in FIG. 8 described above, the image measurement is performed for each color image forming color of the projector to be measured, and the position pattern errors in each forming color are relatively compared. Thus, the color misregistration distribution over the entire projection image of the projector is obtained. Specifically, in particular, in a three-plate type liquid crystal projector, since three liquid crystal panels of RGB are mounted and an image is formed on each panel, the position pattern is measured for each of the three colors of RGB. Then, the color misregistration is inspected by calculating the color misregistration amount from the RGB pattern coordinate values.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
In the image measurement method of this embodiment, as described in the above embodiment, when measuring image distortion, a correction value is calculated using the projection image light of the measurement target projector for the aberration component of the imaging apparatus itself. Therefore, regardless of the spectral characteristics of the projection image light of the projector, the aberration component of the optical system of the imaging device can be accurately corrected, and it can be applied to a wide range with a small number of imaging devices, and the optical characteristics of the projection image can be measured with high accuracy Can do.
(Aspect B)
In (Aspect A), the calibration pattern and the measurement pattern are the same pattern. According to this, as described in the above embodiment, it is possible to more easily calculate a correction value for image distortion.
(Aspect C)
In (Aspect A) or (Aspect B), a calibration pattern is illuminated with light for each basic color that forms a color image, and a calibration pattern for each basic color is photographed by the photographing apparatus, whereby a photographing apparatus for each basic color is obtained. The correction value of the distortion component of the optical characteristic is calculated. According to this, as described in the modification of the above-described embodiment, each projection image light corresponding to the basic color of the color image of the projector to be measured with respect to the aberration component of the imaging system at the time of color shift measurement. Since the correction values are respectively calculated using, the aberration component of the photographing system can be accurately corrected regardless of the spectral characteristics of the projection image light of the projector, and the optical characteristics of the projection image can be measured with high accuracy.
(Aspect D)
In the image measurement apparatus of the present embodiment, as described in the above embodiment, when measuring image distortion, a correction value is calculated using the projection image light of the measurement target projector for the aberration component of the photographing unit itself. Therefore, regardless of the spectral characteristics of the projection image light of the projector, the aberration component of the optical system of the imaging means can be corrected accurately, and it can be applied to a wide range with a small number of imaging devices, and the optical characteristics of the projection image can be measured with high accuracy Can do.
(Aspect E)
In (Aspect D), a calibration pattern is illuminated with light for each basic color that forms a color image, and a calibration pattern for each basic color is photographed by a photographing device, whereby the optical characteristics of the imaging means for each basic color are distorted. Each component correction value is calculated. According to this, as described in the modification of the above-described embodiment, each projection image light corresponding to the basic color of the color image of the projector to be measured with respect to the aberration component of the imaging system at the time of color shift measurement. Since the correction values are respectively calculated using, the aberration component of the photographing system can be accurately corrected regardless of the spectral characteristics of the projection image light of the projector, and the optical characteristics of the projection image can be measured with high accuracy.
(Aspect F)
Using the image measurement apparatus of (Aspect D) or (Aspect E), the quality of the projection image is inspected based on the characteristic value of the projection image obtained by photographing a predetermined pattern projected by the projector to be measured. According to this, as described in the modification of the embodiment, the quality inspection of the image projected by the projector, for example, the inspection of resist, aspect ratio, line bending and color misregistration can be performed with the characteristic value of the projection image. Compared with visual inspection, there is no variation in inspection results.

DESCRIPTION OF SYMBOLS 10 Image measuring device 11 Fixing device 12 Screen 13 Image pick-up device 14 Image analysis means 15 Calibration surface member 20 Projector 31 Coordinate 32 Coordinate 33 Coordinate 34 Coordinate 40 Screen 41 Inspected projection pattern 42 Ideal projection pattern 43 Inspection object position

Japanese Patent No. 3853674

Claims (6)

An optical image created by modulating a light beam emitted from a light source according to image information is projected on a screen by a measurement target projector, and an imaging device that captures the projected image is output from the imaging device An image processing apparatus that analyzes an image signal and calculates a distortion component of the optical characteristics of the projected image, and that measures the optical characteristics of the projected image based on the image signal output from the imaging apparatus. And
The calibration surface of a calibration surface member having a calibration surface of a calibration pattern formed in black and white and in a predetermined pattern is illuminated with monochromatic light by the projector, and the calibration pattern of the calibration surface is photographed by the photographing device, The position of the calibration pattern is analyzed by the image processing device based on the image signal output from the imaging device, and the imaging is performed based on the relative relationship between the analyzed actual calibration pattern position and the ideal calibration pattern position. Calculate the correction value of the distortion component of the optical characteristics of the device,
The projection image generated based on the image information of a predetermined measurement pattern by the projector is projected onto a screen, the projection image is photographed by the photographing device, and the image signal output from the photographing device is calculated. An image measurement method comprising: correcting an optical characteristic of a projection image based on a corrected image signal, wherein the optical characteristic is corrected by a correction value of a distortion component of an optical characteristic of the apparatus. The image measurement method according to claim 1,
The image measurement method, wherein the calibration pattern and the measurement pattern are the same pattern. The image measurement method according to claim 1 or 2,
When the calibration pattern is illuminated using the projector to be measured, the calibration pattern is illuminated with light for each basic color forming a color image by the projector, and the calibration surface is calibrated for each basic color by the photographing apparatus. Each pattern is photographed, the correction value of the distortion component of the optical characteristic of the imaging device for each basic color is calculated by the image processing device, and the projection image of the measurement pattern is projected on the screen by the measurement target projector In this case, the measurement pattern is projected for each basic color, corrected by each correction value corresponding to each basic color, and the relative position between the coordinate positions of the measurement pattern that is the corresponding relationship in the projection image for each basic color. An image measurement method, comprising: calculating a color shift distribution of a projector image from a projector image. An optical image created by modulating a light beam emitted from a light source according to image information is projected on a screen by a measurement target projector, and an imaging device that captures the projected image is output from the imaging device An image processing apparatus that analyzes an image signal and calculates a distortion component of optical characteristics of a projected image, and that measures an optical characteristic of a projected image based on an image signal output from the imaging apparatus.
The imaging device shoots the calibration surface by illuminating the calibration surface of a calibration surface member having a calibration pattern of a calibration pattern formed in black and white with a predetermined pattern with monochromatic light by the projector,
The image processing device analyzes the position of the calibration pattern based on the image signal output from the imaging device, and the relative position between the analyzed actual calibration pattern position and the ideal calibration pattern position Calculate the correction value of the distortion component of the optical characteristics of the imaging device,
The imaging device captures a projection image generated and projected on the screen instead of the calibration surface member by the projector based on image information of a predetermined measurement pattern,
The image processing apparatus corrects an image signal output from the imaging apparatus by a correction value of a distortion component of optical characteristics of the imaging apparatus calculated in advance, and based on the corrected image signal, the optical characteristics of the projection image An image measuring device characterized by measuring the above. The image measurement device according to claim 4,
The photographing apparatus illuminates the calibration pattern with light of each basic color forming a color image by the projector to photograph the calibration pattern of the calibration surface for each basic color,
The image processing device calculates a correction value of a distortion component of the optical characteristics of the imaging device for each basic color,
When projecting a measurement pattern projection image on the measurement target projector, the photographing apparatus projects a measurement pattern for each basic color, and corrects each basic color with correction values corresponding to the basic colors. An image measurement apparatus that calculates a color shift distribution of a projector image from a relative position between coordinate positions of a measurement pattern that is a corresponding relationship in a projection image for each color.   A quality of a projection image is inspected based on a characteristic value of a projection image obtained by photographing a predetermined pattern projected by the projector to be measured using the image measurement device according to claim 4 or 5. Image inspection device.

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