JP2015186080A - Projector and control method of projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector capable of accurately correcting a trapezoidal distortion regardless of the presence/absence of a frame.SOLUTION: A projector 100 includes: a projection optical system 153 which projects an image on a screen SC; a correction control section 1213 which detects the frame within a projection range of the projection optical system 153; and a projection control section 1211 which makes the projection optical system 153 project a measurement image including a plurality of measurement points. The correction control section 1213 detects the measurement points included in the measurement image projected by the projection optical system 153 and measures an inclination of a projection plane with respect to an optical axis of projection light of the projection optical system 153. The correction control section 1213 measures the inclination while using the measurement points projected at positions corresponding to a detection result of the frame.

Description

  The present invention relates to a projector and a method for controlling the projector.

  When an image is displayed on the projection surface by a projector, the projected image is distorted in a trapezoidal shape (hereinafter referred to as trapezoidal distortion) due to the inclination of the projection surface with respect to the optical axis of the projection light (hereinafter referred to as projection angle). There is. Regarding such a problem, Patent Document 1 describes a technique for detecting a frame side of a projection surface, measuring a projection angle, and correcting trapezoidal distortion based on such information. Patent Document 2 describes a technique for correcting a trapezoidal distortion by measuring a projection angle.

JP 2010-50542 A JP 2010-128102 A

The measurement of the projection angle is performed by projecting a measurement image including measurement points for measurement onto the projection surface, capturing the projection surface with an imaging device provided in the projector, and detecting the measurement points from the captured image. When the projection surface has a frame such as a frame side (frame-like boundary line), the measurement image may be displayed so that the measurement points are within the frame. On the other hand, when the projection surface does not have a frame, it is necessary to correct the trapezoidal distortion using only the projection angle. Therefore, it is necessary to measure the projection angle with high accuracy.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a projector capable of accurately correcting trapezoidal distortion regardless of the presence or absence of a frame, and a control method for the projector.

In order to achieve the above object, a projector according to the present invention includes a projection unit that projects an image on a projection surface, a detection unit that detects a frame in the projection range of the projection unit, and a measurement image including a plurality of measurement points. A projection control unit to be projected by the projection unit, and a measurement point included in the measurement image projected by the projection unit are detected, and the inclination of the projection surface with respect to the optical axis of the projection light of the projection unit is measured. A measurement unit, wherein the measurement unit measures the inclination using a measurement point projected at a position corresponding to a detection result of the detection unit.
According to this configuration, the trapezoidal distortion can be accurately corrected regardless of the presence or absence of the frame by changing the position of the measurement point used for the tilt measurement according to the presence or absence of the frame.

In the projector according to the aspect of the invention, the projector may further include a storage unit that stores a plurality of measurement images having different distances between the measurement points, and the projection control unit may include the measurement image based on a detection result of the detection unit. Is selected and projected.
According to this configuration, an image for measurement corresponding to the detection result of the detection unit can be selected and projected onto the projection surface.

Further, in the projector according to the aspect of the invention, when the frame is detected by the detection unit, the projection control unit has a longer distance between the measurement points as the detected frame is larger. Is selected and projected.
According to this configuration, it is possible to increase the measurement accuracy of the inclination of the projection surface when the frame is detected.

In the projector according to the aspect of the invention, the projection control unit may select and project the measurement image having the longest distance between the measurement points when the detection unit does not detect the frame. It is characterized by.
According to this configuration, it is possible to improve the measurement accuracy of the tilt of the projection surface when no frame is detected.

In the projector according to the aspect of the invention, the projection control unit may project a common measurement image regardless of the detection result of the detection unit, and the measurement unit may include a plurality of measurement images included in the common measurement image. Among the measurement points, the inclination is measured using a measurement point projected to a position corresponding to the detection result of the detection unit.
According to this configuration, the keystone distortion correction accuracy is improved by selecting a measurement point from a plurality of measurement points based on the detection result of the detection unit and measuring the tilt using the selected measurement point. Can do.

In the projector according to the aspect of the invention, the projection control unit may project a measurement image including a plurality of sets of measurement points having different distances between the measurement points as the common measurement image, and the measurement unit When the frame is detected by the detection unit, the measurement point group having the longest distance between the measurement points among the measurement point groups projected to the inside of the frame on the projection surface is used. It is characterized by measuring the inclination.
According to this configuration, it is possible to increase the measurement accuracy of the inclination of the projection surface when the frame is detected.

In the projector according to the aspect of the invention, the projection control unit may project a measurement image including a plurality of sets of measurement points having different distances between the measurement points as the common measurement image, and the detection unit. When the frame is not detected by the above, the inclination is measured using a measurement point group having the longest distance between the measurement points on the projection surface.
According to this configuration, it is possible to improve the measurement accuracy of the tilt of the projection surface when no frame is detected.

Further, in the projector according to the aspect of the invention, the projection control unit generates an image for measurement in which the distance between the measurement points is changed according to the detection result of the frame of the detection unit, and projects the measurement image on the projection surface. It is characterized by making it.
According to this configuration, the trapezoidal distortion can be accurately corrected regardless of the presence or absence of the frame by changing the position of the measurement point used for the tilt measurement according to the presence or absence of the frame.

Further, in the projector according to the aspect of the invention, when the frame is detected by the detection unit, the projection control unit has a longer distance between the measurement points as the detected frame is larger. Is generated and projected.
According to this configuration, it is possible to increase the measurement accuracy of the inclination of the projection surface when the frame is detected.

The projector control method of the present invention includes a step of projecting a measurement image including a plurality of measurement points on a projection surface, a step of detecting a frame in a projection range of the projection surface, and the measurement projected on the projection surface. Detecting a measurement point included in the image for measurement and measuring an inclination of the projection surface with respect to the optical axis of the projection light, and the measuring step projects to a position corresponding to the detection result of the frame The inclination is measured using a measurement point to be measured.
According to this configuration, the trapezoidal distortion can be accurately corrected regardless of the presence or absence of the frame by changing the position of the measurement point used for the tilt measurement according to the presence or absence of the frame.

  According to the present invention, it is possible to accurately correct the trapezoidal distortion regardless of the presence or absence of a frame.

It is a block diagram which shows an example of a structure of a projector. It is a figure which shows an example of the image for frame side detection. (A) is a figure which shows the image for 1st projection angle measurement, (B) is a figure which shows the image for 2nd projection angle measurement, (C) is a figure which shows the image for 3rd projection angle measurement. . It is a flowchart which shows the process sequence of 1st Embodiment. It is a figure which shows an example of the image for projection angle measurement of 2nd Embodiment. It is a flowchart which shows the process sequence of 2nd Embodiment.

[First Embodiment]
Embodiments to which the present invention is applied will be described below with reference to the accompanying drawings. FIG. 1 shows an example of the overall configuration of the projector 100 of the present embodiment. The projector 100 projects an image on the screen SC based on image data supplied from an external image supply device (not shown) such as a personal computer or various video players. In the following description, the screen SC is described as an example of the projection surface. However, the projection surface is not limited to the screen SC, and may be a white board, a wall of a room, or the like. Further, the screen SC may have a frame side or may not have a frame side. The image data projected by the projector 100 onto the screen SC may be moving image (video) data or still image data. Further, the projector 100 can project an image on the screen SC or can continue to project a still image on the screen SC. In the following embodiments, a case where an image is projected based on an analog image signal input from an external image supply device via a cable 200 will be described as an example.

  The projector 100 includes a projection unit 150 that forms an optical image roughly, and an image processing system that controls the overall operation of the projector 100 and performs a process of electrically converting an image signal. The projection unit 150 includes a light source unit 151, a light modulation device 152, and a projection optical system 153.

  The light source unit 151 can use a xenon lamp, an ultra-high pressure mercury lamp, an LED (Light Emitting Diode), a laser light source, or the like as a light source. The light source 151 is dimmed on a reflector and an auxiliary reflector (not shown) that guides the light emitted from the light source 151 to the light modulator 152 and the light emitted from the light source 151 on the path to the light modulator 152. A dimmer element (not shown) or the like may be provided.

The light modulation device 152 separates the light emitted from the light source unit 151 into R, G, and B color light by a dichroic mirror or the like, and a plurality (three) of liquid crystal panels (not shown) included in the light modulation device 152. To modulate each color light. The light modulation device 152 combines the modulated color lights with a cross dichroic prism and outputs the combined light to the projection optical system 153. An image based on an image signal (hereinafter referred to as a panel image) is formed on the panel surface of the liquid crystal panel by driving the light modulation device driving unit 141. Light emitted from the light source unit 151 is modulated into image light representing an image by a panel image formed on the liquid crystal panel. The image light modulated in the liquid crystal panel is projected onto the screen SC via the projection optical system 153.
In the present embodiment, the light modulation device 152 that modulates the light emitted from the light source is exemplified by a configuration using three transmissive liquid crystal panels corresponding to each color of RGB, but is not limited thereto. It is not a thing. For example, it is possible to use three reflective liquid crystal panels. In addition, the light modulation device 112 is configured by a system using a single liquid crystal panel and a color wheel, a system using three DMDs (Digital Mirror Device), a system using a single DMD and a color wheel, and the like. May be. Here, when only one liquid crystal panel or DMD is used as the light modulation device 112, a member corresponding to a combining optical system such as a cross dichroic prism is unnecessary. In addition to the liquid crystal panel and the DMD, any configuration that can modulate the light emitted from the light source can be used without any problem.

  The projection optical system 153 includes a zoom lens 1531 that enlarges / reduces the projected image and adjusts the focus. The light modulated by the light modulation device 152 is incident on the projection optical system 153, and this light is projected onto the screen SC through the zoom lens 1531 to form a projected image. The zoom lens 1531 includes a lens group including a plurality of lenses. The zoom lens 1531 is driven by a lens driving unit 143, which will be described later, and the position of each lens is adjusted, so that the zoom adjustment for enlarging / reducing the projected image on the screen SC and the appropriate projection image on the screen SC are performed. Focus adjustment is performed to form an image.

  The image processing system includes a control unit 120 that integrally controls the entire projector 100 and an image processor 130. In addition, the image processing system includes an A / D (Analog-to-Digital) conversion unit 110, a light modulation device driving unit 141, a light source driving unit 142, a lens driving unit 143, and the like. Further, the image processing system includes an imaging unit 171 including a CCD (Charge Coupled Device) camera, a captured image memory 172, a remote controller 181 and an operation unit 182. These elements constituting the image processing system are connected to each other via a bus 105.

  The A / D conversion unit 110 is a device that performs A / D conversion on an analog image signal input from the above-described external image supply apparatus via the cable 200. The A / D converter 110 converts the analog image signal into a digital image signal, and outputs the converted digital image signal to the image processor 130.

The control unit 120 includes a CPU (Central Processing Unit) 121, a ROM (Read Only Memory) 122, and a RAM (Random Access Memory) 123.
The CPU 121 configures the control unit 120 together with the ROM 122, the RAM 123, and the like, and performs overall control of the projector 100. The functional blocks shown in the CPU 121 shown in FIG. 1 are realized by the cooperation of the hardware such as the CPU 121 and the RAM 123 and the program stored in the ROM 122. The control unit 120 of the present embodiment includes a projection control unit 1211, an imaging control unit 1212, and a correction control unit 1213 as functional blocks. Details of these parts will be described later.

  The ROM 122 stores a program executed by the CPU 121 to realize each processing unit described above. Further, the ROM 122 is provided with an adjustment image storage unit 1221 for storing a frame side detection image and a projection angle measurement image. The frame side detection image is an image used when detecting a frame side (frame-like boundary line) of the screen SC. The projection angle measurement image is used to calculate a projection angle that is an inclination of the screen SC with respect to the optical axis of the projection light of the projector 100. FIG. 2 shows an example of a frame side detection image. The frame edge detection image shown in FIG. 2 is an image in which the central portion of the image is formed in white and the peripheral portion surrounding the periphery is formed in black. FIG. 3 shows an example of a projection angle measurement image. 3A shows a first projection angle measurement image, FIG. 3B shows a second projection angle measurement image, and FIG. 3C shows a third projection angle measurement image. The projection angle measurement image includes at least three points (the first to third projection angle measurement images shown in FIGS. 3A to 3C include four measurement points. These measurement points. Are arranged at positions such that the three points do not exist on the same straight line when projected onto the screen SC.The first projection angle measurement image is the image with the longest distance between the measurement points, The third projection angle measurement image is an image having the shortest distance between the measurement points, and the second projection angle measurement image has a distance between the measurement points of the first projection angle measurement image and the third projection angle measurement. In other words, when the distances between the measurement points in the horizontal direction of the first, second, and third projection angle measurement images are X1, X2, and X3, respectively, X1> X2> X3 Similarly, the distances between the measurement points in the vertical direction of the first, second, and third projection angle measurement images are respectively Y1, Y2, and Y2. If 3 was, and Y1> Y2> Y3. In the projection angle measurement image shown in FIG. 3 shows a background portion by oblique lines, may background is black.

  The RAM 123 forms a work area for temporarily storing programs and data executed by the CPU 121 and the image processor 130. Note that the image processor 130 may include a work area necessary for executing each process, such as an image display state adjustment process performed by itself, as a built-in RAM.

The image processor 130 is a functional unit that processes the image data input from the A / D conversion unit 110. The image processor 130 performs processing for adjusting the display state of the image such as brightness, contrast, color density, and hue on the image data to be projected, and the processed image data is converted into a light modulation device driving unit. 141 is output. The image processor 130 can also be configured using a processor that is widely used as a DSP (Digital Signal processor) for trapezoidal distortion correction or image processing. The image processor 130 can also be configured as a dedicated ASIC (Application Specific Integrated Circuit).
The image processor 130 includes a trapezoidal distortion correction unit 131. The trapezoidal distortion correction unit 131 performs a process of deforming the image of the image data output from the A / D conversion unit 110 according to the parameter input from the correction control unit 1213.

  The light modulator driving unit 141 drives the light modulator 152 based on the image signal input from the image processor 130. Thus, a panel image corresponding to the image signal is formed on the panel surface of the liquid crystal panel included in the light modulation device 152, and this panel image is projected onto the screen SC by the projection optical system 153.

  The light source drive unit 142 applies a voltage to the light source unit 151 in accordance with the instruction signal input from the control unit 120, and turns on or off the light source unit 151.

  The lens driving unit 143 can drive the zoom lens 1531 included in the projection optical system 153 to change the zoom state. The zoom state means the degree of magnification (magnification) when the projection optical system 153 projects light transmitted through the light modulation device 152. That is, the lens driving unit 143 can drive the zoom lens 1531 to change the size of an image displayed on the screen SC.

The imaging unit 171 is provided on the front surface of the projector 100, that is, at a position where the projection optical system 153 can capture the direction and range (projection range) in which an image is projected toward the screen SC. The imaging unit 171 has a shooting direction and an angle of view so that the entire projection image projected on the screen SC at a predetermined projection distance falls within at least the imaging range.
The captured image data captured by the imaging unit 171 is output from the imaging unit 171 to the captured image memory 172 and written in a predetermined area of the captured image memory 172. When the image data for one screen is completely written, the captured image memory 172 sequentially inverts a flag for a predetermined area. Therefore, the control unit 120 refers to the flag to perform imaging using the imaging unit 171. You can know if it is completed. The control unit 120 accesses the captured image memory 172 while referring to this flag, and acquires necessary captured image data.

  The remote control control unit 181 receives a radio signal transmitted from a remote control (not shown) outside the projector 100. The remote control includes an operation element (not shown) operated by the user, and transmits an operation signal corresponding to an operation on the operation element as an infrared signal or a radio signal using a radio wave of a predetermined frequency. The remote control unit 181 includes a light receiving unit (not shown) that receives an infrared signal and a receiving circuit (not shown) that receives a radio signal. The remote control unit 181 receives and analyzes the signal transmitted from the remote control, and the contents of the operation by the user. Is generated and output to the control unit 120.

  The operation unit 182 includes an operation panel operator (not shown) disposed on the main body of the projector 100, for example. When the operation unit 182 detects an operation on the operation element, the operation unit 182 outputs an operation signal corresponding to the operation element to the control unit 120. Examples of the operation element include a switch for instructing power ON / OFF and a switch for instructing start of distortion correction processing.

Here, functional blocks provided in the control unit 120 will be described.
The projection control unit 1211 controls the operation of projecting an image by the projection unit 150 based on the image data output from the A / D conversion unit 110. Specifically, the projection control unit 1211 controls the light source unit 151 to be turned on or off by the light source driving unit 142 when the projector 100 is turned on or off, and the image data output from the A / D conversion unit 110 is an image processor. The control etc. which are processed by 130 are performed. When the start of the trapezoidal distortion correction process is instructed by the operation of the operation unit 182 or the remote controller, the projection control unit 1211 reads the frame edge detection image stored in the adjustment image storage unit 1221 and projects it on the screen SC. In addition, the projection control unit 1211 reads out the projection angle measurement image selected by the correction control unit 1213 from the adjustment image storage unit 1221 and causes the image to be projected on the screen SC. The projection control unit 1211 outputs the read image to the image processor 130 together with a command. The frame side detection image or the projection angle measurement image is displayed on the liquid crystal panel of the light modulation device 152 by the light modulation device driving unit 141 controlled by the projection control unit 1211 and projected onto the screen SC.

  The imaging control unit 1212 controls the imaging unit 171 to capture a projection image projected on the screen SC. The captured image data captured by the imaging unit 171 is stored in the captured image memory 172.

The correction control unit 1213 acquires the captured image data stored in the captured image memory 172, and detects the frame side of the screen SC. The captured image memory 172 stores captured image data obtained by capturing the frame edge detection image. The correction control unit 1213 acquires captured image data from the captured image memory 172, performs image processing on the acquired captured image data, and detects the coordinate values of the frame sides of the screen SC. The correction control unit 1213 detects the coordinate values of the frame sides of the screen SC using, for example, the detection method disclosed in Japanese Patent Application Laid-Open No. 2008-21355. The detected coordinate value is a coordinate value in the photographed image data drawn in the photographed image memory 172. When the correction control unit 1213 detects the frame side of the screen SC, the correction control unit 1213 stores information indicating the presence of the frame side and the coordinate value of the frame side in the RAM 123. Further, when the frame side of the screen SC cannot be detected, the correction control unit 1213 stores information indicating no frame side in the RAM 123.
Note that the detection method of the frame side coordinate values by the correction control unit 1213 is not limited to the detection method disclosed in Japanese Patent Application Laid-Open No. 2008-212355. For example, the correction control unit 1213 may apply an edge extraction filter to captured image data obtained by capturing the screen SC and detect the frame side of the screen SC as a boundary line. As the edge extraction filter, various filters capable of extracting the contour of the image, such as a differential filter and a Laplacian filter, can be used.

The correction control unit 1213 selects a projection angle measurement image to be projected on the screen SC based on the detection result of the frame side of the screen SC. The projection angle measurement image selected by the correction control unit 1213 is projected onto the screen SC by the projection control unit 1211 and photographed by the photographing control unit 1212. The correction control unit 1213 measures the projection angle using a measurement point projected at a position corresponding to the detection result of the frame side among the measurement points included in the captured image data of the projection angle measurement image. A specific example of the measurement point selection method will be described with reference to FIG. For the measurement of the projection angle, the correction control unit 1213 selects at least three measurement points included in the captured image data of the projection angle measurement image, and calculates based on the result of the three-dimensional survey for the selected measurement points. To do.
Further, the correction control unit 1213 calculates a correction coefficient for correcting the trapezoidal distortion using the calculated projection angle and the coordinate value of the frame side, or the projection angle. The correction control unit 1213 passes the calculated correction coefficient to the image processor 130, and causes the image processor 130 to perform trapezoidal distortion correction of the input image based on the correction coefficient.

  Next, the processing procedure of this embodiment will be described with reference to the flowchart shown in FIG. This flow starts with an instruction to start trapezoidal distortion correction (when the user operates a button, when the power is turned on, or when the initial screen is projected). The control unit 120 first determines whether or not an operation for instructing start of trapezoidal distortion correction has been input (step S1). When an operation for instructing the start is input (step S1 / YES), the control unit 120 displays a frame side detection image on the screen SC under the control of the projection control unit 1211 (step S2). The projection control unit 1211 of the control unit 120 reads the frame side detection image from the adjustment image storage unit 1221 and outputs the read frame side detection image to the image processor 130 together with a command. The frame side detection image is displayed on the liquid crystal panel of the light modulation device 152 by the light modulation device driving unit 141 controlled by the projection control unit 1211 and projected onto the screen SC (step S2).

Next, in a state where the frame side detection image is projected on the screen SC, the control unit 120 causes the imaging unit 171 to perform imaging under the control of the imaging control unit 1212. The imaging unit 171 captures a frame side detection image projected on the screen SC and stores the captured image data in the captured image memory 172.
Next, the control unit 120 reads and acquires the captured image data from the captured image memory 172 under the control of the correction control unit 1213 (step S3). Next, the control unit 120 performs image processing on the captured image data acquired by the control of the correction control unit 1213 to detect a frame side (step S4). When the correction control unit 1213 detects the frame side of the screen SC, the correction control unit 1213 stores information indicating the presence of the frame side and the coordinate value of the frame side in the RAM 123. Further, when the frame side of the screen SC cannot be detected, the correction control unit 1213 stores information indicating no frame side in the RAM 123.
If the frame side can be detected (step S5 / YES), the correction control unit 1213 selects a projection angle measurement image based on the detected coordinate values of the frame side (step S6). In other words, the correction control unit 1213 selects a projection angle measurement image that can display measurement points within the frame sides and has the maximum distance between the measurement points based on the detected coordinate values of the frame sides (step) S6). A one-to-one correspondence between the coordinate system on the liquid crystal panel and the coordinate system on the photographic image is determined from the coordinates of the frame side detection image formed on the liquid crystal panel and the coordinate values of the frame side detection image in the photographic image. Is obtained. For this reason, using this correspondence, it is possible to compare the detected coordinate values of the frame sides and the positions of the measurement points.
If the correction control unit 1213 cannot detect the frame side (step S5 / NO), the distance between the measurement points in the projection angle measurement image stored in the adjustment image storage unit 1221. The image for measuring the projection angle with the longest is selected (step S7). For example, the first projection angle measurement image shown in FIG. 3A is selected.

When a projection angle measurement image is selected by the correction control unit 1213, the control unit 120 reads the selected projection angle measurement image from the adjustment image storage unit 1221 and controls the screen SC under the control of the projection control unit 1211. (Step S8).
Next, in a state where the projection angle measurement image is projected on the screen SC, the control unit 120 causes the imaging unit 171 to capture the projection angle measurement image projected on the screen SC under the control of the imaging control unit 1212. The captured image data is stored in the captured image memory 172.
When the captured image data is stored in the captured image memory 172, the control unit 120 acquires the captured image data from the captured image memory 172 under the control of the correction control unit 1213 (step S9). The control unit 120 performs three-dimensional surveying based on the acquired captured image data under the control of the correction control unit 1213, and calculates a projection angle (step S10).

  Next, when the coordinate value of the frame side is detected in step S5, the control unit 120 controls the correction control unit 1213 to reduce the trapezoidal distortion using the calculated projection angle and the coordinate value of the frame side. A correction coefficient to be corrected is calculated (step S11). Specifically, the correction control unit 1213 uses the detected coordinate values of the frame sides of the screen SC to calculate a correction coefficient for correcting the shape of the projected image so as to match the shape of the frame sides of the screen. If the coordinate value of the frame side is not detected in step S5, the control unit 120 calculates a correction coefficient for correcting the trapezoidal distortion based on the calculated projection angle under the control of the correction control unit 1213 (step S5). S11). When calculating the correction coefficient, the control unit 120 passes the calculated correction coefficient to the image processor 130, and causes the image processor 130 to perform trapezoidal distortion correction of the input image based on the correction coefficient (step S12). The image whose trapezoidal distortion is corrected by the image processor 130 is projected onto the screen SC under the control of the projection control unit 1211 (step S12).

In the case where the projection surface is a screen SC having a frame side, it is only necessary to perform trapezoidal distortion correction so that the projected image is along the frame side of the screen SC. High accuracy compared to measurement accuracy is not required. For this reason, in this embodiment, when the screen SC has a frame side, the projection control unit 1211 displays the measurement points within the frame side of the screen SC, and the distance between the measurement points is the longest. A projection angle measurement image is selected and projected onto the screen SC. Then, the correction control unit 1213 calculates the projection angle from the captured image data obtained by capturing the projection angle measurement image. In addition, when the projection surface is the screen SC having no frame side, it is necessary to perform trapezoidal distortion correction using only the projection angle, and thus high measurement accuracy of the projection angle is required. For this reason, in the present embodiment, when the projection surface is the screen SC having no frame side, the projection control unit 1211 measures the measurement points from the projection angle measurement images stored in the adjustment image storage unit 1221. The projection angle measurement image having the longest distance is selected. That is, the projection control unit 1211 selects the first projection angle measurement image shown in FIG. 3 and projects it onto the screen SC. Then, the correction control unit 1213 calculates the projection angle from the captured image data obtained by capturing the projection angle measurement image.
As described above, according to the present embodiment, an optimal projection angle measurement image can be selected and projected on the screen SC according to the presence or absence of the frame side, and the projection angle of the screen SC can be calculated. For this reason, the measurement accuracy of the projection angle can be changed according to the presence or absence of the frame side of the screen SC, and the trapezoidal distortion correction can be performed with high accuracy.

[Modification]
In the first embodiment, when it is determined that the frame side exists on the screen SC, the correction control unit 1213 fits the measurement point within the frame side from the projection angle measurement image prepared in advance, and the measurement point. The projection angle measurement image with the longest distance between them was selected and projected onto the screen SC.
In this modification, when the frame side of the screen SC is detected based on the captured image data obtained by capturing the frame side detection image projected on the screen SC, the correction control unit 1213 sets the detected frame side coordinate value. Based on this, a projection angle measurement image is generated. The correction control unit 1213 generates a projection angle measurement image in which measurement points are arranged so as to be within the frame side based on the detected coordinate values of the frame side. As described in the first embodiment, the projection angle measurement image includes at least three measurement points. These measurement points are arranged at positions where the three points do not exist on the same straight line when projected onto the screen SC. Further, the measurement points are arranged such that the distance between the measurement points is as large as possible within the frame of the screen SC when projected onto the screen SC. The generated projection angle measurement image is projected onto the screen SC under the control of the projection control unit 1211, and the projection angle is calculated under the control of the correction control unit 1213 based on the captured image data obtained by capturing the projection angle measurement image.
When the frame side is not detected on the screen SC, the correction control unit 1213 is a projection angle measurement image in which the distance between the measurement points is separated as much as possible on the panel surface of the liquid crystal panel included in the light modulation device 152. Is generated. The generated projection angle measurement image is projected onto the screen SC under the control of the projection control unit 1211, and the projection angle is calculated under the control of the correction control unit 1213 based on the captured image data obtained by capturing the projection angle measurement image.
As described above, in this modification, a projection angle measurement image in which the distance between the measurement points is changed according to the presence or absence of the frame side of the screen SC is generated and projected onto the screen SC, and the projection angle of the screen SC is calculated. . For this reason, the measurement accuracy of the projection angle can be changed according to the presence or absence of the frame side of the screen SC, and the trapezoidal distortion correction can be performed with high accuracy.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the accompanying drawings. The hardware configuration of this embodiment is the same as that of the first embodiment shown in FIG.

FIG. 5 shows an example of the projection angle measurement image of the present embodiment. The projection angle measurement image of this embodiment includes measurement points A1 to A4 (measurement point group A), measurement points B1 to B4 (measurement point group B), and measurement points C1 to C4 (measurement point group C) as measurement points. ). In the present embodiment, the first projection angle measurement image shown in FIG. 3 (A), the second projection angle measurement image shown in FIG. 3 (B), and the third projection angle measurement image shown in FIG. 3 (C). An image synthesized with the image is used as a projection angle measurement image.
The measurement points A1 and A2 and the measurement points A3 and A4 are separated by X4 in the horizontal direction of the projection angle measurement image. Further, the measurement points A1 and A4 and the measurement points A2 and A3 are separated by Y4 in the vertical direction of the projection angle measurement image. Measurement points B1 and B2 and measurement points B3 and B4 are separated by X5 in the horizontal direction of the projection angle measurement image. Further, the measurement points B1 and B4 and the measurement points B2 and B3 are separated by Y5 in the vertical direction of the projection angle measurement image. The measurement points C1 and C2 and the measurement points C3 and C4 are separated by X6 in the horizontal direction of the projection angle measurement image. Further, the measurement points C1 and C4 and the measurement points C2 and C3 are separated by Y6 in the vertical direction of the projection angle measurement image. Note that X4 <X5 <X6 and Y4 <Y5 <Y6.

  This embodiment does not change the projection angle measurement image to be projected according to the detection result of the frame side, but from the common projection angle measurement image to be projected regardless of the detection result of the frame side. A measurement point group corresponding to the detection result is selected, and a projection angle is calculated using the selected measurement point group. In the projection angle measurement image shown in FIG. 5, the background portion is indicated by diagonal lines, but the background portion may be black.

The processing procedure of this embodiment will be described with reference to the flowchart shown in FIG. The processing procedure from S21 to S24 shown in FIG. 6 is the same as the procedure from S1 to S4 shown in FIG.
In step S24, the control unit 120 reads out the captured image data from the captured image memory 172 under the control of the correction control unit 1213, and performs image processing on the read out captured image data to detect a frame side (step S24). ). If the frame side of the screen SC is detected, the correction control unit 1213 stores information indicating the presence of the frame side and the coordinate value of the frame side in the RAM 123. Further, when the frame side of the screen SC cannot be detected, the correction control unit 1213 stores information indicating no frame side in the RAM 123.

  Next, under the control of the projection control unit 1211, the control unit 120 reads out the projection angle measurement image from the adjustment image storage unit 1221 and projects it onto the screen SC (step S25). That is, the control unit 120 reads out the projection angle measurement image from the adjustment image storage unit 1221 by the projection control unit 1211 and outputs the read projection angle measurement image to the image processor 130 together with the command. The projection angle measurement image is displayed on the liquid crystal panel of the light modulation device 152 by the light modulation device drive unit 141 controlled by the projection control unit 1211 and projected onto the screen SC (step S25). Next, in a state where the projection angle measurement image is projected on the screen SC, the control unit 120 controls the imaging unit 171 with the imaging control unit 1212 to perform imaging. The imaging unit 171 captures a projection angle measurement image projected on the screen SC under the control of the capturing control unit 1212 and stores the captured image data in the captured image memory 172. The correction control unit 1213 acquires the captured image data stored in the captured image memory 172 (step S26).

  Next, the control unit 120 controls the correction control unit 1213 based on the information indicating the presence / absence of the frame side stored in the RAM 123 in step S24 and the coordinate value of the frame side when the frame side is detected. Select a measurement point group to be used for measuring the projection angle. That is, the correction control unit 1213 selects a measurement point group used for calculation of the projection angle from the measurement point group reflected in the captured image data of the projection angle measurement image. The correction control unit 1213 selects the measurement point group (measurement point group C) having the longest distance between measurement points when information indicating no frame side is stored in the RAM 123 as information indicating the presence or absence of the frame side. (Step S27). In addition, when the information indicating the presence of a frame side is stored in the RAM 123, the correction control unit 1213 can display the frame side based on the coordinate value of the frame side stored in the RAM 123, and perform measurement. A measurement point group having the longest distance between the points is selected (step S27). That is, the correction control unit 1213 compares the coordinate value of each measurement point with the coordinate value of the frame side, and is a measurement point group that falls within the frame side and has the longest distance between the measurement points. Select.

Next, the control unit 120 performs a three-dimensional survey based on the measurement points included in the selected measurement point group under the control of the correction control unit 1213, and calculates a projection angle (step S28). Next, when the coordinate value of the frame side is detected in step S24, the control unit 120 controls the correction control unit 1213 to reduce the trapezoidal distortion using the calculated projection angle and the coordinate value of the frame side. A correction coefficient to be corrected is calculated (step S29). Specifically, the correction control unit 1213 uses the detected coordinate values of the frame sides of the screen SC to calculate a correction coefficient for correcting the shape of the projected image so as to match the shape of the frame sides of the screen. If the coordinate value of the frame side is not detected in step S24, the control unit 120 calculates a correction coefficient for correcting the trapezoidal distortion based on the calculated projection angle under the control of the correction control unit 1213 (step S24). S29). When calculating the correction coefficient, the control unit 120 passes the calculated correction coefficient to the image processor 130, and causes the image processor 130 to perform trapezoidal distortion correction of the input image based on the correction coefficient (step S30). The image whose keystone distortion is corrected by the image processor 130 is projected onto the screen SC under the control of the projection control unit 1211 (step S30).
In the second embodiment, the measurement points used for calculating the projection angle are selected in units of measurement point groups. However, the measurement points are individually selected based on the detection results of the frame sides of the screen SC. It is also possible.

  As described above, in the present embodiment, when the projection surface is the screen SC having a frame side, the measurement point displayed in the frame side is selected from the captured image data of the projection angle measurement image. Measure the projection angle. Further, when the projection surface is the screen SC having no frame side, the projection angle is measured by selecting the measurement point having the longest distance between the measurement points from the captured image data of the projection angle measurement image. For this reason, the measurement accuracy of the projection angle can be changed according to the presence or absence of the frame side of the screen SC, and the trapezoidal distortion correction can be performed with high accuracy.

  The projector 100 according to this embodiment includes a projection optical system 153, a correction control unit 1213, and a projection control unit 1211. The projection optical system 153 projects an image on the screen SC. The correction control unit 1213 detects a frame within the projection range of the projection optical system 153. The projection control unit 1211 causes the projection optical system 153 to project a projection angle measurement image including a plurality of measurement points. Further, the correction control unit 1213 detects a measurement point included in the projection angle measurement image projected by the projection optical system 153, and is a projection angle that is an inclination of the projection surface with respect to the optical axis of the projection light of the projection optical system 153. Measure. Further, the correction control unit 1213 measures the projection angle using a measurement point projected at a position corresponding to the detection result of the frame. Therefore, the trapezoidal distortion can be accurately corrected regardless of the presence or absence of the frame by changing the position of the measurement point used for the measurement of the projection angle according to the presence or absence of the frame.

  In addition, the projector 100 according to this embodiment includes an adjustment image storage unit 1221 that stores a projection angle measurement image including a plurality of measurement points having different distances between measurement points. Then, the projection control unit 1211 selects and projects the projection angle measurement image based on the detection result of the correction control unit 1213. Therefore, it is possible to project the projection angle measurement image corresponding to the detection result of the frame onto the screen SC.

  In the projector 100 of the present embodiment, when the frame is detected, the projection control unit 1211 selects and projects a measurement image having a longer distance between measurement points as the detected frame is larger. Therefore, the measurement accuracy of the projection angle when the frame is detected can be increased.

  In the projector 100 of the present embodiment, the projection control unit 1211 selects and projects the measurement image having the longest distance between the measurement points when the frame is not detected. Therefore, the measurement accuracy of the projection angle when the frame is not detected can be increased.

  In the projector 100 according to the present embodiment, the projection control unit 1211 projects a common measurement image regardless of the detection result of the frame. The correction control unit 1213 measures the projection angle using a measurement point projected at a position corresponding to the detection result of the frame among a plurality of measurement points included in the common measurement image. Accordingly, by selecting a measurement point from a plurality of measurement points based on the detection result of the frame and measuring the projection angle using the selected measurement point, it is possible to improve the correction accuracy of the trapezoidal distortion.

  In the projector 100 according to the present embodiment, the projection control unit 1211 projects a measurement image including a plurality of sets of measurement points having different distances between measurement points as a common measurement image. When the frame is detected, the correction control unit 1213 measures the projection angle using the measurement point group having the longest distance between the measurement points among the measurement point groups projected to the inside of the frame on the screen SC. . Therefore, the measurement accuracy of the projection angle when the frame is detected can be increased.

  In the projector 100 according to the present embodiment, the projection control unit 1211 projects a measurement image including a plurality of sets of measurement points having different distances between measurement points as a common measurement image. When the frame is not detected, the correction control unit 1213 measures the projection angle using the measurement point group having the longest distance between the measurement points on the screen SC. Therefore, the measurement accuracy of the projection angle when the frame is not detected can be increased.

  Moreover, in the projector 100 of this embodiment, the projection control part 1211 produces | generates the image for a measurement which changed the distance between measurement points according to the detection result of a frame, and makes it project on the screen SC. Therefore, the trapezoidal distortion can be accurately corrected regardless of the presence or absence of the frame by changing the position of the measurement point used for the measurement of the projection angle according to the presence or absence of the frame.

  In the projector 100 of the present embodiment, when the frame is detected, the projection control unit 1211 generates and projects a measurement image having a longer distance between measurement points as the detected frame is larger. Therefore, the measurement accuracy of the projection angle when the frame is detected can be increased.

  The above-described embodiment is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... Projector, 110 ... A / D conversion part, 120 ... Control part, 121 ... CPU, 122 ... ROM, 123 ... RAM, 130 ... Image processor, 131 ... Keystone distortion correction part (memory | storage part), 141 ... Light modulation Device driving unit 142 ... Light source driving unit 143 Lens driving unit 150 Projecting unit 151 Light source unit 152 Light modulation device 153 Projection optical system (projecting unit) 171 Imaging unit 172 Shooting Image memory, 1211... Projection control unit, 1212... Shooting control unit, 1213... Correction control unit (detection unit, measurement unit).

Claims (10)

A projection unit that projects an image onto the projection surface;
A detection unit for detecting a frame in the projection range of the projection unit;
A projection control unit that projects a measurement image including a plurality of measurement points by the projection unit;
A measurement unit that detects a measurement point included in the measurement image projected by the projection unit and measures the inclination of the projection surface with respect to the optical axis of the projection light of the projection unit, and
The measurement unit measures the inclination using a measurement point projected at a position corresponding to a detection result of the detection unit;
Projector. A storage unit for storing a plurality of measurement images having different distances between the measurement points;
The projection control unit selects and projects the measurement image based on the detection result of the detection unit,
The projector according to claim 1. When the frame is detected by the detection unit, the projection control unit selects and projects a measurement image having a longer distance between the measurement points as the detected frame is larger.
The projector according to claim 2. The projection control unit selects and projects the measurement image having the longest distance between the measurement points when the frame is not detected by the detection unit;
The projector according to claim 2 or 3, wherein The projection control unit projects a common measurement image regardless of the detection result of the detection unit,
The measurement unit measures the inclination using a measurement point projected at a position corresponding to a detection result of the detection unit among a plurality of measurement points included in the common measurement image;
The projector according to claim 1. The projection control unit projects a measurement image including a plurality of sets of measurement points having different distances between the measurement points as the common measurement image,
The measurement unit, when the frame is detected by the detection unit, a measurement point group having the longest distance between the measurement points among the measurement point groups projected on the projection surface inside the frame. Measuring the tilt using,
The projector according to claim 5. The projection control unit projects a measurement image including a plurality of sets of measurement points having different distances between the measurement points as the common measurement image,
When the frame is not detected by the detection unit, the inclination is measured using a measurement point group having the longest distance between the measurement points on the projection surface;
The projector according to claim 5 or 6. The projection control unit generates a measurement image in which the distance between the measurement points is changed according to the detection result of the frame of the detection unit, and causes the projection surface to project the measurement image.
The projector according to claim 1. When the frame is detected by the detection unit, the projection control unit generates and projects a measurement image with a longer distance between the measurement points as the detected frame is larger.
The projector according to claim 8. Projecting a measurement image including a plurality of measurement points on a projection surface;
Detecting a frame in a projection range of the projection surface;
Detecting a measurement point included in the measurement image projected on the projection surface, and measuring the inclination of the projection surface with respect to the optical axis of the projection light, and
The measuring step includes measuring the inclination using a measurement point projected at a position corresponding to the detection result of the frame;
A projector control method characterized by the above.

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