JP2012078683A - Projector and trapezoidal distortion correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely perform trapezoidal distortion correction in a short focus projector.SOLUTION: This projector 1 includes: a projection part 50 for projecting an image to a screen; an image pickup part 60 for picking up a projection image projected to the screen by the projection part 50 to obtain a pickup image; a determination part 74 for determining whether or not a first image for correction to be used for the trapezoidal distortion correction of the projection image is projected so as to stay in the image pickup area of the image pickup part on the screen by the projection part; and a correction image control part 76 for, when it is determined that the first image for correction is not projected so as to stay in the image pickup area, making the projection part project a second image for correction to be used for the trapezoidal distortion correction of the projection image, that is, the image which is smaller than the first image for correction instead of the first image for correction.

Description

  The present invention relates to a projector and a trapezoidal distortion correction method.

  2. Description of the Related Art Conventionally, a projector captures a trapezoidal distortion correction image projected on a screen with a camera attached to the front surface of a housing, and performs trapezoidal distortion correction based on the captured trapezoidal distortion correction image ( For example, see Patent Documents 1 and 2).

JP 2003-289485 A JP 2007-53784 A

However, in a short focus projector, since the distance to the screen is short, the projection area may not fit in the imaging area. In particular, when the distance to the screen is short and the zoom of the lens is wide, the projection area may not fit in the imaging area. When the projection area does not fit in the imaging area, the entire area of the trapezoidal distortion correction image projected on the screen cannot be captured. Therefore, the keystone distortion cannot be corrected based on the entire area of the keystone distortion correction image, and the keystone distortion cannot be corrected accurately.
In addition, a means for always projecting a correction image having a small area regardless of the distance to the screen so as to fit in the imaging region is conceivable. However, in this means, when the distance to the screen is long, or the lens Even when the zoom is telephoto, a correction image having a small area is always projected, which causes another problem that the correctable region is limited.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for accurately correcting trapezoidal distortion in a short focus projector.

In order to solve the above-described problem, a projector according to one embodiment of the present invention includes a projection unit that projects an image on a screen, and an imaging that captures a projection image projected on the screen by the projection unit and acquires a captured image. And a determination unit that determines whether or not the first correction image used for correcting the trapezoidal distortion of the projection image is projected by the projection unit so as to be within the imaging region of the imaging unit on the screen. When it is determined that the first correction image is not projected so as to fit in the imaging region, the second correction image is used for correcting the trapezoidal distortion of the projection image instead of the first correction image. A correction image control unit that projects an image smaller than the first correction image onto the projection unit.
According to the above configuration, when the distance to the screen is short and the first correction image is not projected so as to be within the imaging area, a second correction image smaller than the first correction image is displayed on the screen. The projected and projected second correction image is accommodated in the imaging area, and the entire area of the second correction image projected on the screen can be captured. That is, even if the distance to the screen is short, the keystone distortion can be corrected based on the entire area of the second correction image. That is, according to the above configuration, the trapezoidal distortion correction can be accurately performed in the short focus projector.
Further, according to the above configuration, when the first correction image is projected so as to be within the imaging region because the distance to the screen is long, the first correction image is used instead of the second correction image. Since the projection is performed, it is possible to ensure a wider correctionable area than the method of projecting a correction image having a small area (an image corresponding to the second correction image) regardless of the distance to the screen. become.

In the projector, the projection unit includes a single focus lens, and the determination unit fits the first correction image in the imaging region based on distance information indicating a distance between the projector and the screen. Thus, it may be determined whether or not the projection is performed.
According to the above configuration, when the projector has a single focus lens instead of a zoom lens, whether or not the first correction image is projected so as to be within the imaging region depends on the distance to the screen. Therefore, in a projector having a single focus lens, the determination can be easily performed by using the distance information. In other words, according to the above configuration, the keystone distortion can be corrected easily and accurately in a projector having a single focus lens.

In the projector, the projection unit projects a distance calculation image used for calculating the distance onto the screen, and the determination unit analyzes the captured image related to the distance calculation image projected onto the screen. The distance information may be acquired.
According to the above configuration, the projector can acquire distance information based on the image for distance calculation projected on the screen by itself, and can accurately correct the trapezoidal distortion based on the information. That is, according to the above configuration, the projector having a single focus lens can easily and accurately correct the trapezoidal distortion without adding special hardware such as a distance measuring sensor.

In the projector, the projection unit includes a zoom lens, and the determination unit is based on distance information indicating a distance between the projector and the screen, and zoom information indicating a current zoom state of the projection unit. Then, it may be determined whether or not the first correction image is projected so as to be within the imaging region.
According to the above configuration, when the projector has a zoom lens instead of a single focus lens, the determination as to whether or not the first correction image is projected so as to be within the imaging region is made by determining the distance to the screen and the zoom. Therefore, in a projector having a zoom lens, the determination can be easily performed by using the distance information and the zoom information. That is, according to the above configuration, it becomes possible to easily and accurately correct the trapezoidal distortion in a projector having a zoom lens.

In the projector, the projection unit projects a distance / zoom state calculation image used for calculation of the distance and the zoom state onto the screen, and the determination unit projects the distance / zoom state projected onto the screen. The captured image related to the calculation image may be analyzed to acquire the distance information and the zoom information.
According to the above configuration, the projector can acquire the distance information and the zoom information based on the distance / zoom calculation image projected on the screen by itself, and can accurately correct the trapezoidal distortion based on the information. Become. That is, according to the above configuration, a projector having a zoom lens can easily and accurately correct trapezoidal distortion without adding special hardware such as a distance measuring sensor.

In the projector, the correction image control unit calculates an image size that fits in the imaging area when it is determined that the first correction image is not projected so as to fit in the imaging area, and You may make it project the said 2nd image for a correction | amendment of the largest size which fits on the said projection part.
According to the above configuration, the second correction image that can capture the entire region and the largest second correction image is projected onto the screen. It becomes possible to correct the trapezoidal distortion based on the whole area. That is, according to the above configuration, the trapezoidal distortion can be corrected with higher accuracy in the short focus projector.

When it is determined that the first correction image is projected so as to be within the imaging region, the projector performs the projection based on the analysis result of the captured image related to the first correction image. Based on the result of analysis of the captured image related to the second correction image when it is determined that the first correction image is not projected so as to fit in the imaging region after correcting the trapezoidal distortion of the image. A correction processing unit that corrects the trapezoidal distortion of the projected image may be further provided.
According to the above configuration, the keystone distortion can be automatically corrected without requiring any user operation.

In order to solve the above problem, a trapezoidal distortion correction method according to another aspect of the present invention includes a projection unit that projects an image on a screen, a projection image projected on the screen by the projection unit, and a captured image. And a first correction image used by the determination unit of the projector for correcting the trapezoidal distortion of the projection image by the projection unit. It is determined whether or not the projection is performed so as to fit within the imaging area of the imaging unit on the screen, and the correction image control unit of the projector projects the first correction image so as to fit within the imaging area. If it is determined that the correction is not performed, instead of the first correction image, the second correction image used for correcting the trapezoidal distortion of the projection image, the first correction image Characterized in that to project remote small image on the projection portion.
According to the above configuration, when the distance to the screen is short and the first correction image is not projected so as to be within the imaging area, a second correction image smaller than the first correction image is displayed on the screen. The projected and projected second correction image is accommodated in the imaging area, and the entire area of the second correction image projected on the screen can be captured. That is, even if the distance to the screen is short, the keystone distortion can be corrected based on the entire area of the second correction image. That is, according to the above configuration, the trapezoidal distortion correction can be accurately performed in the short focus projector.

(A) is a schematic external view of the projector according to the first embodiment of the present invention, and (b) is a schematic external view of the projector according to the second embodiment. 1 is a schematic configuration diagram of a projector according to a first embodiment of the invention. 2 is a functional block of the projector according to the first embodiment of the invention. It is an example of the image memorize | stored in the pattern image memory | storage part, (a) is an example of the image for distance calculation, (b) is an example of the image for 1st correction | amendment, (c) An example of the image for 2nd correction | amendment It is. (A) is an example of a determination table referred to by the determination unit, (b) is an example of a distance measurement table referred to by the determination unit, and (c) is a triangulation technique to calculate the distance to the screen. (D) is an example of a correction image selection table referred to by the correction image control unit. 5 is a flowchart illustrating an example of the operation of the projector according to the first embodiment of the invention. It is a schematic diagram which shows typically the relationship between the projection area | region by the projector by 1st Embodiment, and the image for a correction | amendment, (a) is a figure which shows a mode that a projector projects the image for a correction | amendment of normal size on a screen. (B) is a figure which shows a mode that a projector projects the image for correction | amendment of a reduced size on a screen. It is a functional block of the projector which concerns on the 2nd Embodiment of this invention. (A) is an example of a determination table referred to by the determination unit, and (b) is an example of a zoom information confirmation table referred to by the determination unit. It is a flowchart which shows an example of operation | movement of the projector which concerns on the 2nd Embodiment of this invention. (A) is a schematic diagram showing how a conventional projector projects a correction image (normal size) on the screen, and (b) is a schematic diagram showing how a conventional projector projects a correction image (reduced size) on the screen. FIG.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic external view of a projector according to the first and second embodiments of the present invention. FIG. 2 is a schematic configuration diagram of the projector according to the first embodiment of the invention. The projector 1 according to the first embodiment of the present invention is a short-focus projection type color liquid crystal projector, and as shown in FIG. 1A, a projection lens 48 and a camera 68 are provided on the front surface (screen direction) of the housing. And are arranged. The projection lens 48 is a so-called single focus lens that is not a zoom lens.

  As illustrated in FIG. 2, the projector 1 includes a projection unit 50, an imaging unit 60, a captured image processing unit 70, and a projection image generation unit 80. The projection unit 50 includes the illumination unit 10, the color separation / synthesis unit 20, and the projection optical system 40, and projects an image on the screen 9. The projection optical system 40 has a projection lens 48 (single focus lens).

  The illumination unit 10 includes a light source 11, a first fly eye lens 12, and a second fly eye lens 13. The light source 11 includes a lamp 14 made of a high-pressure mercury lamp or a metal halide lamp, and a reflector 15 that reflects light from the lamp 14. Each fly-eye lens 12, 13 is composed of a plurality of lenses 16, 17. The fly-eye lenses 12 and 13 function as uniform illumination means for uniformizing the illuminance distribution of the light source light in liquid crystal light valves 30 to 32 (described later) that are illumination areas.

  The color separation / combination unit 20 includes a transmissive liquid crystal light valve for each of different colors of dichroic mirrors 21 and 22, reflection mirrors 23 to 25, relay lenses 26 to 28, R (red), G (green), and B (blue). Light modulators) 30 to 32 and a cross dichroic prism 33. The light emitted from the light source 11 is made uniform in illuminance distribution by the fly-eye lenses 12 and 13 in the liquid crystal light valves 30 to 32 which are illuminated areas.

  The dichroic mirrors 21 and 22 are formed, for example, by laminating a dielectric multilayer film on the glass surface, and selectively reflect light of a predetermined color and transmit light of other wavelengths. That is, the blue / green light reflecting dichroic mirror 21 transmits the red light LR of the light flux from the light source 11 and reflects the blue light LB and the green light LG. Further, the dichroic mirror 22 reflecting green light transmits the blue light LB and reflects the green light LG among the blue light LB and the green light LG reflected by the dichroic mirror 21.

  As a result, among the light incident from the illumination unit 10, the red light LR passes through the dichroic mirror 21, is reflected by the reflection mirror 25, and enters the red light light valve 30. The green light LG is reflected by the dichroic mirror 22 and enters the light valve 31 for green light. The blue light LB passes through the dichroic mirror 22 and then enters the light valve 32 for blue light through a relay system 29 including a relay lens 26, a reflection mirror 23, a relay lens 27, a reflection mirror 24, and a relay lens 28. It is like that.

  The light valves 30 to 32 are configured as, for example, an active matrix transmissive liquid crystal device, and are driven based on a video signal subjected to signal processing. The color lights LR, LG, and LB modulated by the light valves 30 to 32 are incident on the cross dichroic prism 33.

  The cross dichroic prism 33 has a structure in which right angle prisms are bonded together, and a mirror surface that reflects the red light LR and a mirror surface that reflects the blue light LB are formed in a cross shape on the inner surface. Then, after the three color lights LR, LG, and LB are combined by these mirror surfaces to form light representing a color image, it is enlarged and projected onto the screen 9 by the projection lens 48 (single focus lens). ing.

  The imaging unit 60 captures a projection image projected on the screen 9 by the projection unit 50 and acquires a captured image. The imaging unit 60 is a camera unit that includes a camera 68 disposed in front of the projector 1 and generates a still image related to a projection image projected on the screen 9. As a matter of course, the imaging area on the screen 9 by the imaging unit 60 changes according to the distance between the projector 1 and the screen 9, and the shorter the distance, the smaller the imaging area.

  The captured image processing unit 70 processes the captured image captured by the imaging unit 60. Note that the captured image processing unit 70 mainly performs image processing related to trapezoid rejection correction, details of which will be described later.

  The projection image generation unit 80 generates a projection image to be projected on the screen 9 by the projection unit 50. The projected image generation unit 80 also performs trapezoidal distortion correction, which will be described later in detail.

  FIG. 3 is a functional block diagram of the projector according to the first embodiment of the invention. FIG. 4 is an example of an image stored in the pattern image storage unit 72. FIG. 5 is an example of information referred to by the determination unit 74 or the correction image control unit 76. As described with reference to FIG. 2, the projector 1 includes the projection unit 50, the imaging unit 60, the captured image processing unit 70, and the projection image generation unit 80 as illustrated in FIG. 3.

  The captured image processing unit 70 includes a pattern image storage unit 72, a captured image memory 73, a determination unit 74, a correction image control unit 76, and a correction image analysis unit 77. The pattern image storage unit 72 stores various information. For example, the pattern image storage unit 72 is a pattern image projected by the projection unit 50 and used for distance calculation, and is an image projected by the projection unit 50 and used for correcting trapezoidal distortion of the projection image. The first correction image and the second correction image are stored.

  FIG. 4A is an example of a distance calculation image stored in the pattern image storage unit 72. The distance calculation image shown in FIG. 4A is an image of a known size (width W × height H) in which a ten-character of a known size (length h of one side of a circumscribed rectangle) is drawn at the center. is there. The unit of length h, width W, and height H is, for example, a pixel. FIG. 4B is an example of a first correction image stored in the pattern image storage unit 72. The first correction image shown in FIG. 4B is an image in which trapezoidal distortion correction patterns or symbols (indicated by crosses in FIG. 4B) are drawn at the four corners. FIG. 4C is an example of a second correction image stored in the pattern image storage unit 72. The second correction image shown in FIG. 4C is an image in which trapezoidal distortion correction patterns or symbols (indicated by crosses in FIG. 4C) are drawn at the four corners. As shown in FIGS. 4B and 4C, the second correction image is smaller in width than the first correction image. Since the second correction image is smaller in width than the first correction image, in the following description, the first correction image is referred to as a normal-size correction image, and the second correction image. Is also referred to as a reduced-size correction image.

  The distance calculation image stored in the pattern image storage unit 72 is read by the correction image control unit 76 and projected onto the screen 9 through the processes of the projection image generation unit 80 and the projection unit 50. . The same applies to a normal size correction image or a reduced size correction image.

  The captured image memory 73 stores the captured image output from the imaging unit 60. For example, the captured image memory 73 is a captured image obtained by the imaging unit 60 capturing the distance calculation image projected on the screen 9 by the projection unit 50 (hereinafter, a captured image related to the distance calculation image). A captured image obtained by capturing the normal-size correction image projected on the imaging unit 60 (hereinafter, a captured image related to the normal-size correction image), and a reduced-size correction image projected on the screen 9 by the projection unit 50 Are captured by the image capturing unit 60 (hereinafter referred to as a captured image related to a reduced-size correction image).

  The determination unit 74 determines whether or not the normal-size correction image is projected by the projection unit 50 so as to fit in the imaging region on the screen 9 of the imaging unit 60. Specifically, the determination unit 74 is projected based on distance information indicating the distance between the projector 1 and the screen 9 so that the normal-size correction image fits in the imaging region on the screen 9 of the imaging unit 60. It is determined whether or not. More specifically, the determination unit 74 acquires distance information to the screen 9, refers to the determination table, and is projected so that the normal-size correction image fits in the imaging area on the screen 9 of the imaging unit 60. It is determined whether or not. The determination table may be stored in advance in a place (a storage area in the projector 1, for example, the pattern image storage unit 72. The same applies hereinafter) where the determination unit 74 can refer to the projector 1 before shipment from the factory. This is a stored table in which the distance to the screen 9 is stored in association with availability information indicating whether or not a normal-size correction image is projected so as to fit in the imaging region.

  FIG. 5A is an example of a determination table referred to by the determination unit 74. The determination table shown in FIG. 5A stores availability information “0 (contains)” in association with the distance “1.2 m or more” to the screen 9 as an actual measurement value before shipment from the factory. Is stored in association with the distance “less than 1.2 m”. Therefore, the determination unit 74 refers to the determination table shown in FIG. 5A, and when the distance to the screen 9 is 1.5 m, for example, the normal size correction image is displayed on the screen 9 of the imaging unit 60. When it is determined that the projection is performed so as to fit in the upper imaging area, and the distance to the screen 9 is 0.8 m, for example, the normal size correction image fits in the imaging area on the screen 9 of the imaging unit 60. It determines with not projecting. That is, when the distance to the screen 9 is shorter than the reference value (1.2 m in the example of FIG. 5A), the determination unit 74 does not project the normal size correction image so as to fit in the imaging region. Otherwise, it is determined that the normal-size correction image is projected so as to fit in the imaging region.

  Although there are various methods for acquiring the distance information to the screen 9, in the present embodiment, the determination unit 74 is a captured image related to the distance calculation image projected by the projection unit 50, that is, imaging. The captured image related to the distance calculation image stored in the image memory 73 is analyzed, and the distance to the screen 9 is obtained. Although details will be described later, the distance calculation image is projected onto the screen 9 by the projection unit 50, and a captured image related to the distance calculation image is acquired by the imaging unit 60 and stored in the captured image memory 73.

  In addition, there are various methods for obtaining the distance to the screen 9 by analyzing the captured image related to the distance calculation image. For example, the determination unit 74 determines the size of the ten characters in the captured image related to the distance calculation image. , And the distance to the screen 9 is obtained by referring to the distance measurement table. In this case, the distance measurement table is a table stored in advance in a place where the determination unit 74 can refer to the projector 1 before shipment from the factory, and relates to the distance to the screen 9 and the distance calculation image. It is the table which matched and memorize | stored the size of the ten characters in a captured image.

  Further, for example, the determination unit 74 may measure the height of the captured image related to the distance calculation image instead of the crossed character size, refer to the distance measurement table, and acquire the distance to the screen 9. In this case, the distance measurement table is a table stored in advance in a place where the determination unit 74 can refer to the projector 1 before shipment from the factory, and relates to the distance to the screen 9 and the distance calculation image. It is the table which memorize | stored and matched the height of the captured image.

  FIG. 5B is an example of a distance measurement table referred to by the determination unit 74. The distance measurement table shown in FIG. 5B is a distance calculation image associated with each distance (0.5 m, 1 m, 1.5 m,...) To the screen 9 as an actual measurement value before shipment from the factory. The actual measurement values (h1, h2, h3,...) Of the crossed character size in the captured image and the actual measurement values (H1, H2, H3,...) Of the captured image related to the distance calculation image are stored. . Therefore, the determination unit 74 refers to the distance measurement table shown in FIG. 5B, and acquires a distance of 0.5 m to the screen 9 when the measurement size of the crossed character is, for example, h1. Note that when the measurement size of the crossed characters is a value between two values stored in the measurement table such as between h1 and h2, the determination unit 74 determines a value corresponding to each of the two values. Should be adopted. For example, when the measurement size is a value obtained by adding 3/10 of the difference between the value of h2 and the value of h1 to the value of h1, the distance to the screen 9 is set to 0.5 m + (1.0 m-0. 5 m) × 0.3 = 0.65 m. The same applies to the height and deviation amount (described later) of the captured image related to the distance calculation image.

  The correction image control unit 76 reads the distance calculation image from the pattern image storage unit 72 and outputs the distance calculation image to the projection image generation unit 80. For example, when a trapezoidal distortion correction start command (trapezoidal distortion correction start command) indicating the start of the keystone distortion correction of the projector 1 is received, the distance calculation image is read from the pattern image storage unit 72 and output to the projection image generation unit 80. To do. Thereby, the image for distance calculation is projected on the screen 9 through the processes of the projection image generation unit 80 and the projection unit 50, the captured image related to the image for distance calculation is acquired by the imaging unit 60, and the image for distance calculation is related to The captured image is stored in the captured image memory 73. The captured image related to the distance calculation image stored in the captured image memory 73 is used for distance calculation by the determination unit 74 as described above.

  Further, the correction image control unit 76 reads the normal size correction image from the pattern image storage unit 72 when the determination unit 74 determines that the normal size correction image is projected so as to fit within the imaging region. Are output to the projection unit 50, and a normal-size correction image is projected onto the projection unit 50. Further, when the determination unit 74 determines that the normal size correction image is not projected so as to fit in the imaging region, the correction image control unit 76 reads the reduced size correction image from the pattern image storage unit 72. The image is output to the projection unit 50, and the correction image having a reduced size is projected onto the projection unit 50.

  When the determination unit 74 determines that the normal-size correction image is projected so as to fit in the imaging region, the correction-image analysis unit 77 uses the captured image related to the normal-size correction image for trapezoidal distortion correction. Analysis is performed, and the analysis result is output to the projection image generation unit 80. In addition, when the determination unit 74 determines that the normal-size correction image is not projected so as to fit in the imaging region, the correction-image analysis unit 77 uses the captured image related to the reduced-size correction image for trapezoidal distortion correction. The analysis result is output to the projection image generation unit 80.

More specifically, when the determination unit 74 determines that the normal-size correction image is projected so as to be within the imaging region, the normal-size correction image is projected onto the screen 9, and is captured by the imaging unit 60. Since the captured image related to the normal size correction image is acquired, the correction image analysis unit 77 calculates the degree of trapezoidal distortion by a known method based on the captured image related to the normal size correction image. Then, a parameter for correcting the trapezoidal distortion is generated, and the parameter is output to the projection image generation unit 80 as an analysis result of the captured image.
On the other hand, when the determination unit 74 determines that the normal-size correction image is not projected so as to fit in the imaging region, the reduced-size correction image is projected onto the screen 9, and the reduced-size correction is performed by the imaging unit 60. Since the captured image related to the target image is acquired, the correction image analysis unit 77 calculates the degree of trapezoidal distortion by a known method based on the captured image related to the correction image of the reduced size, and the trapezoidal distortion Is generated, and the parameter is output to the projection image generation unit 80 as the analysis result of the captured image.

  The projection image generation unit 80 includes a frame memory 82, a projection image drawing processing unit 83, and a correction processing unit 84. The correction processing unit 84 uses the analysis result of the captured image related to the normal size correction image by the correction image analysis unit 77 or the analysis result of the captured image related to the reduced size correction image by the correction image analysis unit 77. Based on this, a trapezoidal distortion correction is performed on the projected image by performing a trapezoidal distortion correction process on the input image. That is, when the determination unit 74 determines that the normal-size correction image is projected so as to fit in the imaging region, the correction processing unit 84 converts the correction image analysis unit 77 into the normal-size correction image. Based on the analysis result of the captured image, a trapezoidal distortion correction is performed on the projection image by performing a trapezoidal distortion correction process on the input image, and the determination unit 74 projects the normal size correction image so that it fits in the imaging region. If it is determined that the correction is not performed, the correction processing unit 84 performs a trapezoidal distortion correction process on the input image based on the analysis result of the captured image related to the correction image of the reduced size by the correction image analysis unit 77. To correct the trapezoidal distortion for the projected image.

  The projected image drawing processing unit 83 stores the distance calculation image, the normal size correction image, and the reduced size correction image output from the correction image control unit 76 in the frame memory 82. Further, the projection image drawing processing unit 83 stores the input image after the trapezoidal distortion correction by the projection image generation unit 80 in the frame memory 82. The information stored in the frame memory 82 is output to the projection unit 50 and is projected on the screen 9 by the projection unit 50.

  Hereinafter, the operation of the projector 1 will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of the operation of the projector 1. Note that the flowchart shown in FIG. 6 is started, for example, by receiving a trapezoidal distortion correction start command from the user.

  The correction image control unit 76 reads the distance calculation image from the pattern image storage unit 72 and outputs the distance calculation image to the projection image drawing processing unit 83. The projected image drawing processing unit 83 stores the distance calculation image in the frame memory 82. The projection unit 50 projects the distance calculation image stored in the frame memory 82 onto the screen 9 (step S10).

  The imaging unit 60 captures the distance calculation image projected on the screen 9 by the projection unit 50, and acquires a captured image related to the distance calculation image (step S12). The imaging unit 60 stores the captured image related to the distance calculation image in the captured image memory 73.

  The determination unit 74 reads the captured image related to the distance calculation image stored in the captured image memory 73, analyzes the captured image, and acquires the distance to the screen 9 (step S14). The determination unit 74 that has acquired the distance to the screen 9 determines whether or not the normal-size correction image is projected by the projection unit 50 so as to be within the imaging region on the screen 9 of the imaging unit 60 (step). S16).

  In step S <b> 16, when the determination unit 74 determines that the normal size correction image is projected so as to fit in the imaging region (step S <b> 16: Yes), the normal size correction image is read from the pattern image storage unit 72. To the projected image drawing processing unit 83. The projected image drawing processing unit 83 stores the normal size correction image in the frame memory 82. The projection unit 50 projects the normal size correction image stored in the frame memory 82 onto the screen 9 (step S18). Subsequent to step S18, the imaging unit 60 captures a normal-size correction image projected on the screen 9 by the projection unit 50, and acquires a captured image related to the normal-size correction image (step S20). The imaging unit 60 stores a captured image related to the normal-size correction image in the captured image memory 73.

  On the other hand, when the determination unit 74 determines in step S16 that the normal-size correction image is not projected so as to be within the imaging region (step S16: No), the reduced-size correction image is received from the pattern image storage unit 72. Read out and output to the projected image drawing processing unit 83. The projected image drawing processing unit 83 stores the reduced size correction image in the frame memory 82. The projection unit 50 projects the reduced-size correction image stored in the frame memory 82 onto the screen 9 (step S22). Subsequent to step S22, the imaging unit 60 captures a reduced-size correction image projected on the screen 9 by the projection unit 50, and acquires a captured image related to the reduced-size correction image (step S24). The imaging unit 60 stores the captured image related to the reduced size correction image in the captured image memory 73.

  Subsequent to step S20 or step S22, the correction image analysis unit 77 reads and analyzes the captured image related to the correction image stored in the captured image memory 73 (step S26). That is, when it is determined that the normal-size correction image is projected so as to fit in the imaging region, the correction-image analyzing unit 77 converts the normal-size correction image into the normal-size correction image stored in the captured image memory 73. When the captured image is read and analyzed, and it is determined that the normal-size correction image is not projected so as to fit in the imaging region, the correction image analysis unit 77 stores the reduced image stored in the captured image memory 73. A captured image related to the size correction image is read and analyzed. The correction image analysis unit 77 outputs parameters for correcting trapezoidal distortion, which is the analysis result of the captured image related to the correction image, to the projection image generation unit 80.

  The correction processing unit 84 performs trapezoidal distortion correction processing on the input image that is input thereafter based on the analysis result of the captured image related to the correction image by the correction image analysis unit 77 (step S28). That is, when the captured image related to the normal size correction image is analyzed, the correction processing unit 84 performs the trapezoidal distortion correction process on the input image based on the analysis result of the captured image related to the normal size correction image. When the captured image related to the reduced size correction image is analyzed, the correction processing unit 84 corrects the trapezoidal distortion for the input image based on the analysis result of the captured image related to the reduced size correction image. Process. The correction processing unit 84 outputs the input image after the trapezoidal distortion correction processing to the projection image drawing processing unit 83.

  The projection image drawing processing unit 83 stores the input image after the trapezoidal distortion correction by the projection image generation unit 80 in the frame memory 82. The projection unit 50 projects the input image after the trapezoidal distortion correction stored in the frame memory 82 onto the screen 9 (step S30). Then, this flowchart ends.

  FIG. 7 is a schematic diagram schematically illustrating a relationship between a projection area and a correction image by the projector according to the first embodiment. FIG. 11 is a schematic diagram schematically illustrating a relationship between a projection area and a correction image by a projector according to a conventional embodiment.

  FIG. 7A schematically shows how the projector 1 according to the first embodiment projects a normal-size correction image onto the screen 9. FIG. 7B schematically shows how the projector 1 according to the first embodiment projects a reduced-size correction image onto the screen 9. In FIG. 7A, the broken line shown in the upper part of the projector 1 is the imaging area of the camera 68, the projection area of the projection lens 48 (single focus lens), and the solid line is the normal size projected over the entire projection area. This is a correction image. In FIG. 7B, the broken line shown in the upper part of the projector 1 is the imaging area of the camera 68 and the projection area of the projection lens 48 (single focus lens), and the solid line is the area excluding the partial area on the right side of the projection area. It is the correction image of the reduced size projected. In FIG. 7B, the alternate long and short dash line indicates the size of a normal-size correction image that is not projected for comparison.

  FIG. 11A is a schematic diagram shown for comparison with the present invention, and schematically shows a state in which the conventional projector A projects a correction image (normal size) onto the screen 9. is there. FIG. 11B is a schematic diagram shown for comparison with the present invention, and schematically shows how the conventional projector B projects a correction image (reduced size) onto the screen 9. is there. In FIG. 11A, the broken line shown in the upper part of the conventional projector A is the imaging area of the camera, the projection area of the projection lens, and the solid line is the correction image (normal size) projected over the entire projection area. . In FIG. 11 (b), the broken line shown in the upper part of the conventional projector B is the image pickup area of the camera, the projection area of the projection lens, and the solid line is for correction projected on the area excluding the partial area on the right side of the projection area. It is an image (reduced size).

  The projector 1 according to the first embodiment projects a normal size correction image onto the screen 9 as shown in FIG. 7A when the distance to the screen 9 is longer than the reference value. As shown in FIG. 7B, when the distance to the screen 9 is less than the reference value, a reduced size correction image is projected onto the screen 9. Therefore, when the distance to the screen 9 is short, in the case of the conventional projector A, as shown in FIG. 11A, the correction image (normal size) does not fit in the imaging region, and therefore a part of Since the trapezoidal distortion correction is performed using the captured image related to the missing correction image (normal size), the keystone distortion correction cannot be performed with high accuracy. However, according to the projector 1 according to the first embodiment, As shown in FIG. 7B, since the correction image for the reduced size fits in the imaging region, the trapezoidal distortion correction is performed using the captured image for the entire correction image for the reduced size. Trapezoidal distortion correction can be performed. In other words, according to the first embodiment, even when the short-focus projector 1 is used close to the screen 9, trapezoidal distortion correction is performed based on the entire region of the reduced-size correction image. The keystone distortion can be corrected well.

  Further, as shown in FIG. 11B, as a projector different from the conventional projector A, a reduced size correction image is always projected regardless of the distance to the screen 9, and the entire reduced size correction image is projected. Even when there is a projector B that performs trapezoidal distortion correction using such a captured image, the projector 1 according to the first embodiment is more effective than the projector B. That is, when the distance to the screen 9 is long, the projector B certainly performs trapezoidal distortion correction using the captured image related to the entire correction image, but the size of the correction image to be used is a reduced size. The correctable area is limited. In other words, according to the first embodiment, when the short-focus projector 1 is used close to the screen 9, as described above, the keystone distortion correction is performed using the entire area of the correction image of the reduced size as described above with high accuracy. When the keystone distortion is corrected and used at a distance, the trapezoidal distortion correction is performed using a normal-size correction image larger than the reduced-size correction image. Therefore, the captured image always associated with the reduced-size correction image is used. As compared with the projector B that performs the trapezoidal distortion correction using the, it is possible to secure a wide correction area.

  In the first embodiment, the determination unit 74 of the projector 1 measures the size of the crossed character in the captured image related to the distance calculation image, or measures the height of the captured image related to the distance calculation image. Although the aspect which acquires the distance to the screen 9 was demonstrated, the aspect which acquires the distance to the screen 9 is not limited to this. For example, the determination unit 74 may calculate the distance to the screen 9 using a triangulation technique. That is, the determination unit 74 determines the distance from the center position of the projection lens 48 (single focus lens), the center position of the lens of the camera 68, and the imaging position of the cross character in the captured image related to the distance calculation image to the screen 9. It may be calculated. Since the center position of the projection lens 48 (single focus lens) and the center position of the lens of the camera 68 are not changed, the distance to the screen 9 and the imaging for the distance calculation image before the projector 1 is shipped from the factory. A distance measurement table in which the cross-captured imaging position in the image is stored in association with each other is stored in advance in a place where the determination unit 74 can refer to the cross-sectional imaging position. And the distance to the screen 9 may be obtained by referring to the distance measurement table.

  FIG. 5C is an example of a distance measurement table when the distance to the screen 9 is calculated using the triangulation technique described above. The distance measurement table shown in FIG. 5C is a distance calculation image associated with each distance (0.5 m, 1 m, 1.5 m,...) To the screen 9 as an actual measurement value before shipment from the factory. As an example of the imaging position of the crossed character in the captured image, the measured value (Z1, Z2, Z3) of the deviation amount of the imaging position of the crossed character from the center of the image corresponding to the optical axis of the camera 68 in the captured image related to the distance calculation image. , ...) is remembered. Therefore, the determination unit 74 refers to the distance measurement table shown in FIG. 5C when the measured deviation amount of the crossed character from the image center is Z1, for example, and the distance to the screen 9 is 0.5 m. To get.

  In the first embodiment, the mode in which the determination unit 74 of the projector 1 analyzes the captured image related to the distance calculation image and obtains the distance to the screen 9 has been described. However, the distance to the screen 9 is acquired. The mode to perform is not limited to this. The projector 1 may include a distance sensor (not shown) using infrared rays, and the determination unit 74 may acquire distance information from the distance sensor to the screen 9. The same applies to the projector 2 of the second embodiment described later.

  In the first embodiment, the projector 1 stores two types of correction images having different sizes such as a normal size correction image and a reduced size correction image in the pattern image storage unit 72. Although the mode in which one of the two types of correction images is output to the screen 9 has been described, the correction image projected on the screen 9 is not limited to the above two types. For example, the projector 1 stores n (n is an integer greater than or equal to 3) types of correction images having different sizes in the pattern image storage unit 72, and n types of correction images according to the distance to the screen 9. Among them, the correction image having the maximum size that can be accommodated in the imaging region may be projected onto the screen 9. The same applies to the projector 2 of the second embodiment described later.

  FIG. 5D shows a pattern image in which a total of four types of correction images including one type of normal size correction image and three types of reduced size correction images are stored in the pattern image storage unit 72 as the above-described n types of specific examples. 6 is an example of a correction image selection table that is referred to by the correction image control unit when stored in the storage unit. The correction image selection table shown in FIG. 5D is the shortest distance to the screen 9 when the correction image (G1) having a reduced size whose width is 80% of the normal size fits in the imaging region before factory shipment. (For example, 1.0 m) and actually measured the shortest distance (for example, 0.8 m) to the screen 9 when the correction image (G2) having a reduced size of 60% of the normal size fits in the imaging region. Then, information (G1) for specifying a correction image to be selected in association with each range of distances to the screen 9 (1.0 to 1.2 m, 0.8 to 1.0 m, and less than 0.8 m). ~ G3) are stored. Therefore, the correction image control unit 76 refers to the correction image selection table and determines the normal size correction image according to the distance to the screen 9 when it is determined that the correction image is not projected so as to fit in the imaging region. The reduced size correction image is read from the pattern image storage unit 72 and output to the projection unit 50. The correction image control unit 76 acquires distance information to the screen 9 from the determination unit 74.

  In the first embodiment, the projector 1 stores in advance the reduced size correction image in the pattern image storage unit 72 separately from the normal size correction image, and captures the normal size correction image. Although it has been described that the reduction-size correction image stored in advance in the pattern image storage unit 72 is read and output to the projection unit 50 when it is determined that the projection is not performed so as to fit in the area, the pattern image storage unit 72 does not have to store a correction image of a reduced size in advance. For example, the correction image control unit 76 determines that the normal size correction image stored in the pattern image storage unit 72 has a width when it is determined that the normal size correction image is not projected so as to fit in the imaging region. It is also possible to generate a reduced-size correction image obtained by reducing a predetermined amount, and output the generated reduced-size correction image to the projection unit 50. The same applies to the projector 2 of the second embodiment described later.

Further, the correction image control unit 76 may determine the predetermined amount according to the distance to the screen 9. For example, when it is determined that the normal-size correction image is not projected so as to fit in the imaging region, the correction image control unit 76 calculates the size of the correction image that fits in the imaging region, and the maximum fits in the imaging region. A value for obtaining a correction image having a reduced size may be determined as the predetermined amount. The same applies to the projector 2 of the second embodiment described later.
According to this configuration, the correction image having a reduced size that can capture the entire area and having the largest reduced size is projected onto the screen 9, so that the reduced size of the image that has been fully projected onto the imaging area is projected. The trapezoidal distortion can be corrected based on the entire area of the correction image. That is, according to the above configuration, the keystone distortion can be corrected with higher accuracy.

  In the first embodiment, the projector 1 includes the correction image analysis unit 77. However, the projector 1 may not include the correction image analysis unit 77. When the projector 1 does not include the correction image analysis unit 77, the user checks the normal size correction image or the reduced size correction image projected on the screen 9 by the projection unit 50, and the projector 1 includes the correction image analysis unit 77. An adjustment unit (not shown; for example, a rotary knob) is operated to correct the trapezoidal distortion of the correction image on the screen 9. In this case, since the adjustment in which the trapezoidal distortion of the correction image is eliminated is maintained on the screen 9, a trapezoidal distortion correction process is performed on the input image input thereafter. The same applies to the projector 2 of the second embodiment described later.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. The projector 2 according to the second embodiment of the present invention is a short-focus projection type color liquid crystal projector, and as shown in FIG. 1B, a projection lens 49 and a camera 68 are provided on the front surface (screen direction) of the housing. And are arranged. The projection lens 49 is a zoom lens.

  FIG. 8 is a functional block diagram of a projector according to the second embodiment of the invention. FIG. 9 is an example of information referred to by the determination unit 75 or the correction image control unit 76. As illustrated in FIG. 8, the projector 2 includes a projection unit 51, an imaging unit 60, a captured image processing unit 71, and a projection image generation unit 80. That is, the projection unit 51 and the captured image processing unit 71 included in the projector 2 according to the second embodiment are different from the projection unit 50 and the captured image processing unit 70 included in the projector 1 according to the first embodiment. The image pickup unit 60 and the projection image generation unit 80 included in are the same as those of the projector 1. Although the schematic configuration diagram of the projector 2 corresponding to the schematic configuration diagram of the projector 1 (FIG. 2) is omitted, the difference between the projection unit 51 of the projector 2 and the projection unit 50 of the projector 1 is the projection unit of the projector 1. 50 includes a projection lens 48 (single focus lens) which is a single focus lens, whereas the projection unit 51 of the projector 2 includes a projection lens 49 (zoom lens) and a zoom mechanism (not shown) of the projection lens 49. It is.

  Hereinafter, a description will be given focusing on differences from the projector 1 according to the first embodiment. As shown in FIG. 8, the captured image processing unit 71 includes a pattern image storage unit 72, a captured image memory 73, a determination unit 75, a correction image control unit 76, and a correction image analysis unit 77. The pattern image storage unit 72, the captured image memory 73, the correction image control unit 76, and the correction image analysis unit 77 are the same as those of the projector 1 according to the first embodiment.

  The determination unit 75 determines whether or not the normal-size correction image is projected by the projection unit 51 so as to fit in the imaging region on the screen 9 of the imaging unit 60. Specifically, the determination unit 75 is based on distance information indicating the distance between the projector 2 and the screen 9 and zoom information indicating the current zoom state of the projection unit 51 (zoom mechanism). It is determined whether or not the correction image is projected so as to fit in the imaging region on the screen 9 of the imaging unit 60. More specifically, the determination unit 75 acquires distance information and zoom information to the screen 9 and refers to the determination table so that the normal-size correction image fits in the imaging region on the screen 9 of the imaging unit 60. It is determined whether or not to project. The determination table is a table that is stored in advance in a location that can be referred to by the determination unit 75 before the projector 2 is shipped from the factory, and the distance to the screen 9, the zoom state, and the normal-size correction image are stored. It is the table which matched and memorize | stored the availability information which shows whether it is projected so that it may fit in an imaging region.

  FIG. 9A is an example of a determination table referred to by the determination unit 75. The determination table shown in FIG. 9A is a measured value before shipment from the factory, the distance to the screen 9 is “1.2 m or more”, the zoom state is “tele”, and the distance to the screen 9 is “1.2 m or more”. In addition, the zoom state “wide”, the distance “0.8 to less than 1.2 m” to the screen 9 and the availability information “0 (contains)” are stored in association with the zoom state “tele”. Distance “0.8 to 1.2 m” and zoom state “wide”, distance to screen 9 “less than 0.8” and zoom state “tele”, distance to screen 9 “less than 0.8” ”And“ 1 (not fit) ”information is stored in association with the zoom state“ wide ”. In the zoom state, tele means telephoto side, and wide means wide angle side.

  Accordingly, the determination unit 75 refers to the determination table shown in FIG. 5A, and when the distance to the screen 9 is 1.0 m and the zoom state is tele, a normal size correction image is displayed. When it is determined that the projection is performed so as to fit within the imaging area on the screen 9 of the imaging unit 60, and the distance to the screen 9 is, for example, 1.0 m and the zoom state is wide, the normal size correction image is displayed. It determines with not projecting so that it may fit in the imaging area on the screen 9 of the imaging part 60. FIG. That is, the determination unit 75 determines that the normal-size correction image is not projected so as to be within the imaging region as the distance to the screen 9 is shorter and the zoom state is at the telephoto side.

  Although there are various methods for acquiring the distance information to the screen 9, in this embodiment, the determination unit 75 is a captured image related to the distance / zoom state calculation image projected by the projection unit 51, That is, the captured image related to the distance / zoom state calculation image stored in the captured image memory 73 is analyzed to obtain the distance to the screen 9. The distance / zoom state calculation image is the same image as the distance calculation image in the first embodiment. Specifically, the determination unit 75 calculates the distance to the screen 9 using a triangulation technique. In other words, the determination unit 75 includes the center position of the projection lens 49 (zoom lens), the center position of the lens of the camera 68, and the image position of the cross in the captured image related to the distance / zoom state calculation image to the screen 9. Calculate the distance. Note that details are as described with reference to FIG. 5C in the first embodiment.

  There are various methods for acquiring the zoom information. In this embodiment, the determination unit 75 analyzes the captured image related to the above-described distance / zoom state calculation image to obtain zoom information. Specifically, the determination unit 75 measures the size of the crossed characters in the captured image related to the distance / zoom state calculation image, refers to the zoom information confirmation table, and acquires zoom information. The zoom information confirmation table is a table stored in advance in a place that can be referred to by the determination unit 75 before the projector 2 is shipped from the factory, and includes zoom information, distance information, and a distance / zoom state calculation image. It is the table which matched and memorize | stored the size of the ten characters in the captured image which concerns.

  For example, the determination unit 75 may measure the height of the captured image related to the distance / zoom state calculation image instead of the crossed character size, refer to the zoom information confirmation table, and acquire the zoom information. In this case, the zoom information confirmation table is a table stored in advance in a place where the determination unit 75 can refer to the projector 2 before shipment from the factory, and the zoom information, the distance information, and the distance / zoom state calculation are calculated. It is the table which memorize | stored and matched the height of the captured image which concerns on a work image.

  FIG. 9B is an example of a zoom information confirmation table referred to by the determination unit 75. In the zoom information confirmation table shown in FIG. 9B, as the actual measurement values before shipment from the factory, the distances to the screen 9 (0.5 m, 1 m, 1.5 m,...) And the zoom status (tele / In association with the image of the distance / zoom state calculation, the actual value (h10, h11, h20, h21,...) Of the crossed character size in the captured image related to the distance / zoom state calculation image and the captured image related to the distance / zoom state calculation image Are measured values (H10, H11, H20, H21,...). Therefore, the determination unit 75 refers to the zoom information confirmation table shown in FIG. 9B, and when the distance to the screen 9 already acquired is, for example, 1.0 m and the measurement size of the cross is, for example, h20, Get tele as zoom information. The determination unit 75 performs the same processing as in the first embodiment when the measurement size of the crossed characters is a value between two values stored in the zoom information confirmation table such as between h10 and h11. do it. The same processing can be performed when the distance to the screen 9 is a value between the two values stored in the zoom information confirmation table. However, both the distance to the screen 9 and the measured size of the cross are between the two values. Since it takes time to calculate the value, at least one value of the distance to the screen 9 or the measurement size of the crossed characters may be finely stored in the zoom information confirmation table. For example, in the zoom information confirmation table shown in FIG. 9, the distance is in units of 0.5 m, but may be in units of 0.1 m.

  When the projector 2 includes a distance sensor (not shown) using infrared rays or the like as described above, the determination unit 75 may acquire distance information from the distance sensor to the screen 9. The determination unit 75 may acquire zoom information directly from the projection optical system 41.

  Hereinafter, the operation of the projector 2 will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of the operation of the projector 2. Of steps S110, S112, S114, S115, S116, S118, S120, S122, S124, S126, S128, and S130 shown in FIG. 10, steps S110, S112, S114, S118, S120, S122, S124, S126, S128 and S130 are the same as steps S10, S12, S14, S18, S20, S22, S24, S26, S28, and S30 of the projector 1 according to the first embodiment shown in FIG. Is omitted.

  Subsequent to step S <b> 112, the determination unit 75 reads the captured image related to the distance / zoom state calculation image stored in the captured image memory 73, analyzes the captured image, and acquires the distance to the screen 9. (Step S114). Specifically, the determination unit 75 calculates the distance to the screen 9 using a triangulation technique. The determination unit 75 that has acquired the distance to the screen 9 further analyzes the captured image and acquires the zoom distance (step S115). Specifically, the determination unit 75 measures the size of the crossed characters in the captured image related to the distance / zoom state calculation image, refers to the zoom information confirmation table, and acquires zoom information.

  The determination unit 75 that has acquired the distance information to the screen 9 and the zoom information determines whether or not the normal-size correction image is projected by the projection unit 51 so as to fit in the imaging region on the screen 9 of the imaging unit 60. Is determined (step S116).

  In step S116, when the determination unit 75 determines that the normal-size correction image is projected so as to be within the imaging region (step S116: Yes), the determination unit 75 sequentially executes steps S118, S120, S126, S128, and S130. This flowchart ends. On the other hand, when the determination unit 75 determines in step S116 that the normal-size correction image is not projected so as to fit in the imaging region (step S116: No), steps S122, S124, S126, S128, and S130 are sequentially executed. Then, this flowchart ends.

  As described above, in the second embodiment, in consideration of the zoom state of the projection lens 49 (zoom lens) in addition to the distance to the screen 9, either the normal size or the reduced size correction image is output. ing. In other words, in the second embodiment, even when the projection lens is a zoom lens, a correction image having an appropriate size that can fit in the projection area is projected. Therefore, according to the second embodiment, even when the distance to the screen 9 is short or the zoom state is tele, it is possible to perform trapezoidal distortion correction based on the entire area of the projected correction image. Therefore, even in a projector having a zoom lens, the keystone distortion can be corrected with high accuracy.

  A program for executing each process of the projectors 1 and 2 according to the embodiment of the present invention is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. Accordingly, the above-described various processes related to the projectors 1 and 2 according to the embodiment of the present invention may be performed. Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if the WWW system is used. “Computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable non-volatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.

  Further, the “computer-readable recording medium” refers to a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention. For example, in the above-described embodiment, the light source 11 is configured by a high-pressure mercury lamp or a metal lamp, but a solid light source such as an LED (Light Emitting Diode) light source or a laser, or other light sources may be used. In the above-described embodiment, the transmissive liquid crystal light valves 30 to 32 are used as the light modulator. However, a reflective light modulator such as a reflective liquid crystal light valve may be used. Also, a micromirror array device that modulates the light emitted from the light source 11 can be used by controlling the emission direction of the incident light for each micromirror as a pixel.

DESCRIPTION OF SYMBOLS 1, 2 ... Projector, 9 ... Screen, 10 ... Illumination part, 11 ... Light source, 12 ... 1st fly eye lens, 13 ... 2nd fly eye lens, 14 ... Lamp, 15 ... Reflector, 16, 17 ... Lens, 20 ... color separation / synthesis unit, 21, 22 ... dichroic mirror, 23, 24, 25 ... reflection mirror, 26, 27, 28 ... relay lens, 29 ... relay system, 30, 31, 32 ... light valve (light modulation device), 33 ... Cross dichroic prism, 40, 41 ... Projection optical system, 48 ... Projection lens (single focus lens), 49 ... Projection lens (zoom lens), 50, 51 ... Projection unit, 60 ... Imaging unit, 68 ... Camera, 70 71 ... Captured image processing unit, 72 ... Pattern image storage unit, 73 ... Captured image memory, 74, 75 ... Determination unit, 76 ... Correction image control unit, 77 ... Correction image Analyzing unit, 80 ... projection image generating unit, 82 ... frame memory, 83 ... projection image drawing processor, 84 ... correction processing unit

Claims (8)

A projection unit that projects an image onto a screen;
An imaging unit that captures a projected image projected on the screen by the projection unit and obtains a captured image;
A determination unit that determines whether or not the first correction image used for correcting the trapezoidal distortion of the projected image is projected by the projection unit so as to be within the imaging region of the imaging unit on the screen;
When it is determined that the first correction image is not projected so as to fit within the imaging region, a second correction image used for correcting the trapezoidal distortion of the projection image instead of the first correction image A correction image control unit that projects an image smaller than the first correction image onto the projection unit. The projection unit has a single focus lens,
The determination unit determines whether or not the first correction image is projected so as to be within the imaging region based on distance information indicating a distance between the projector and the screen. The projector according to claim 1. The projection unit is
Projecting a distance calculation image used for calculating the distance onto the screen,
The determination unit
The projector according to claim 2, wherein the captured image related to the image for distance calculation projected on the screen is analyzed to acquire the distance information. The projection unit includes a zoom lens,
The determination unit fits the first correction image in the imaging region based on distance information indicating a distance between the projector and the screen and zoom information indicating a current zoom state of the projection unit. The projector according to claim 1, wherein it is determined whether or not the projection is performed. The projection unit is
Projecting the distance / zoom state calculation image used for calculating the distance and the zoom state on the screen;
The determination unit
The projector according to claim 4, wherein the captured image related to the distance / zoom state calculation image projected on the screen is analyzed to acquire the distance information and the zoom information. The corrected image control unit
When it is determined that the first correction image is not projected so as to fit in the imaging area, the image size that fits in the imaging area is calculated, and the second correction image having the maximum size that fits in the imaging area is calculated. The projector according to any one of claims 1 to 5, wherein the projector is projected onto the projection unit. When it is determined that the first correction image is projected so as to fit in the imaging region, the keystone distortion of the projection image is based on the analysis result of the captured image related to the first correction image. To correct
When it is determined that the first correction image is not projected so as to fit in the imaging region, the trapezoidal distortion of the projection image is calculated based on the analysis result of the captured image related to the second correction image. The projector according to claim 1, further comprising a correction processing unit that performs correction. A method of correcting a trapezoidal distortion of the projection image in a projector comprising: a projection unit that projects an image on a screen; and an imaging unit that captures a projection image projected on the screen by the projection unit and acquires a captured image.
The determination unit of the projector determines whether or not the first correction image used for correcting the trapezoidal distortion of the projection image is projected by the projection unit so as to be within the imaging region of the imaging unit on the screen. And
When the correction image control means of the projector determines that the first correction image is not projected so as to fit in the imaging region, the trapezoid of the projection image is used instead of the first correction image. A trapezoidal distortion correction method, wherein a second correction image used for distortion correction and smaller than the first correction image is projected onto the projection unit.

Images