JP2005130239A - Projector device, and method for correcting projected image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector device capable of correcting the inclination of an image which is generated in a projected image. <P>SOLUTION: The angle and directions of rotation (clockwise, counterclockwise), which have the optical axis of a projection lens as a center and are generated by the inclination of the projector device 2, are obtained by using an angle sensor 3. A control circuit 5 generates a correction image which is obtained by performing rotation by a rotation angle about the optical axis of the projection lens in a rotating direction opposite to the rotating direction of the projection lens which is obtained by the angle sensor 3. The image corrected in inclination is converted into an image light, by using only part of the effective pixel area of a liquid crystal panel and is projected to a screen 1 through the lens. The image is projected, by using only part of the effective pixel area of the liquid crystal panel, and hence the problems wherein the image is protruded from the liquid crystal panel and the whole image is not projected, when projecting the image rotated by a prescribed angle with respect to the original image are solved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projector apparatus and a projection image correction method for correcting an image inclination generated in a projection image.

  2. Description of the Related Art Conventionally, various techniques for correcting distortion and shift generated in an image projected on a screen from a projector device have been proposed.

  In Patent Document 1 that discloses a correction device that corrects trapezoidal distortion, two active distance sensors 101 and 102 are provided at different positions on the front surface of the projector device main body 100 as shown in FIG. The distance to each is detected. The control microcomputer 104 calculates the tilt angle of the projector apparatus main body 100 with respect to the screen 200 based on the detection results of the active distance sensors 101 and 102. Based on the calculated tilt angle, the pixel data of each line is set so that the projected image light of the liquid crystal panel 103 has a trapezoidal distortion shape opposite to the trapezoidal distortion shape of the projection screen due to the inclination angle of the projector apparatus main body 100. Thinning adjustment is performed by the video circuit 105.

JP 2000-122617 A

  However, Patent Document 1 described above discloses only a technique for correcting trapezoidal distortion that occurs in the vertical and horizontal directions of a projected image, and does not consider any technique for correcting the tilt of the projected image. For example, when the pedestal on which the projector apparatus is installed is tilted around the optical axis of the projection lens, the image projected on the screen is tilted according to the tilt of the pedestal as shown in FIG.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a projector device and a projection image correction method capable of correcting the inclination of an image generated in a projection image.

  In order to achieve such an object, a projector device according to claim 1 is provided on a screen based on an angle detection unit that detects an inclination angle around an optical axis of a projection lens of the projector device, and an inclination angle detected by the angle detection unit. Control means for correcting the inclination of the projected image around the optical axis of the projection lens.

  According to the first aspect of the present invention, the angle detection means detects the tilt angle around the optical axis of the projection lens of the projector device, and corrects the tilt of the projected image according to the detected tilt angle. Therefore, even when the projector device is tilted around the optical axis of the projection lens, an image without tilt can be projected onto the screen.

  According to a second aspect of the present invention, in the projector device according to the first aspect, the control means is based on the tilt angle detected by the angle detection means and a rotation direction around the optical axis of the projection lens. An image in which the original image is tilted by the tilt angle in a rotation direction opposite to the rotation direction is generated.

  According to the second aspect of the present invention, based on the inclination angle detected by the angle detection means and the rotation direction around the optical axis of the projection lens, the original image is obtained by the inclination angle in the rotation direction opposite to the rotation direction. Generate a tilted image. Therefore, since the original image can be tilted by an angle corresponding to the tilt angle around the optical axis of the projection lens, an image without tilt can be projected onto the screen even when the projector device is tilted.

  According to a third aspect of the present invention, in the projector device according to the first or second aspect, the light from the light source is processed into projection light corresponding to the image in the pixel area, and the video light from the pixel area is passed through the lens. An image projecting means for projecting onto the screen is provided, and when projecting the image whose tilt is corrected onto the screen, the image is projected onto the screen using a part of the pixel area. .

  According to the third aspect of the present invention, when an image whose tilt is corrected is projected onto the screen, the image is projected onto the screen using a part of the pixel area. Therefore, when the original image is tilted to correct the tilt of the image, it is possible to prevent a problem that the image protrudes from the pixel area and there is a portion that cannot be projected.

  According to a fourth aspect of the present invention, in the projector device according to the third aspect, the control means compares the inclination angle detected by the angle detection means with a predetermined threshold value, and the inclination angle is the predetermined value. When the value is smaller than the threshold value, the whole of the pixel area is used to project an image before correcting the inclination onto the screen.

  According to a fourth aspect of the present invention, the inclination angle of the projector device is compared with a predetermined threshold value, and when the inclination angle is smaller than the predetermined threshold value, an image before correcting the inclination is projected onto the screen. Therefore, when the image tilt is not a concern without correcting the image, the projected image is projected by using the pixel area to the maximum without correcting the image tilt. It can be enlarged and displayed.

  The projected image correction method according to claim 5 measures the distance to the screen on which the image is projected, calculates the relative positional relationship between the screen and the projector device based on the distance information, and reduces the trapezoidal distortion of the projected image. An image projected on the screen on the basis of the tilt angle detected by the tilt angle detecting step, the tilt angle detecting step for detecting the tilt angle around the optical axis of the projection lens of the projector device, and the tilt angle detecting step. And an image correction step of correcting the inclination of the projection lens around the optical axis.

  The invention according to claim 5 calculates the tilt angle of the screen for projecting the image to correct the trapezoidal distortion of the projected image, and after correcting the trapezoidal distortion, obtains the tilt angle around the optical axis of the projection lens of the projector device. The tilt of the projected image is corrected. Accordingly, it is possible to perform trapezoidal distortion correction, which is somewhat complicated in processing, from a rectangular original image. Further, by performing the trapezoidal correction and the image inclination correction, it is possible to project an image having no shift or distortion on the screen.

  The present invention can provide a projector device capable of correcting the inclination of an image generated in a projection image and a projection image correction method thereof.

  Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the projector device 2 according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, the projector device 2 of the present embodiment receives the reflected light of the image projected on the screen 1 by the projection lens optical system 8 and determines the contrast value for determining the focal position of the projected image. An automatic focus detection device 20 that calculates the distance, a first passive distance measuring device 30 that measures the distance from the projector device 2 to the screen 1 at a plurality of points in the left-right direction (horizontal direction) of the screen 1, and the projector device 2 An image is input from the second passive distance measuring device 40 that measures the distance to the screen 1 at a plurality of points in the vertical direction (vertical direction) of the screen 1 and a device such as a personal computer (not shown) and projected onto the screen 1. A projection image generation unit 6 that outputs display data, a display drive unit 7 that outputs display data to the projection lens optical system 8, and a display drive unit A projection lens optical system 8 that projects the display data output by the screen 1 onto the screen 1, and a stepping motor that moves the projection lens optical system 8 along the optical axis in order to change the focal length of the projection lens optical system 8 An optical system drive unit 9, a memory unit 10 storing data and commands necessary for the configuration of the projector device 2, an angle sensor 3 for detecting the tilt of the projector device 2, and a control circuit 5 for controlling these units, have.

  The angle sensor 3 includes an angle sensor such as a gyro sensor. The inclination angle around the optical axis of the projection lens of the projector apparatus 2, that is, the inclination angle in the rotation direction around the optical axis of the projection lens, and the rotation direction (clockwise, counterclockwise) are obtained. For example, when the pedestal (not shown) on which the projector device 2 is installed is inclined not diagonally but obliquely, the projector device 2 is also inclined obliquely. This tilt causes the projection lens optical system 8 to tilt around the optical axis, and the image projected on the screen 1 also tilts around the optical axis of the projection lens according to the tilt of the pedestal.

  The automatic focus detection device 20 receives the reflected light of the image projected on the screen 1 by the projection lens optical system 8 and the electric signal output from the light reception sensor 21 to calculate the contrast value of the image. And an arithmetic unit 22 for calculating In this embodiment, a CCD line sensor or the like can be applied as the light receiving sensor 21.

  The contrast value appearing in the high-frequency component of the image signal has a characteristic that the contrast value is maximized at the in-focus position where the projected image is focused on the screen, and decreases as the position deviates from the in-focus position. Using this characteristic, the projection light of the image projected from the projection lens optical system 8 detects the position (focus position) of the projection lens optical system 8 when the image is formed on the screen 1.

  FIG. 2 shows a configuration diagram of the projector device 2 shown in FIG. 1 as viewed from the front. A projection lens is provided in front of the projector device 2. The projection lens is included in a projection lens optical system (which may include a condenser lens) 8, and an image is projected onto the screen 1 through the projection lens.

  As shown in FIG. 2, the first passive distance measuring device 30 includes a pair of lenses 31 a and 31 b that are spaced apart by a base line length a in the horizontal direction on the plane that forms the front of the projector device 2. An imaging unit 31 is provided. Similarly, the second passive distance measuring device 40 includes a pair of lenses 41a and 41b that are spaced apart by a base line length b in the vertical direction on the plane that forms the front of the projector device 2 as shown in FIG. It has an imaging unit 41 provided. In the present embodiment, as shown in FIG. 2, the direction parallel to the base line length a of the imaging unit 31 is referred to as the first reference direction of the projector device 2. A direction parallel to the base line length b of the imaging unit 41 is referred to as a second reference direction of the projector device 2. As shown in FIG. 3A, the first passive distance measuring device 30 calculates a tilt angle θ1 of the screen 1 with respect to the first reference direction (the horizontal direction of the projector device 2). Measure the distance to the distance measuring position. As shown in FIG. 3B, the second passive distance measuring device 40 calculates a tilt angle θ2 of the screen 1 with respect to the second reference direction (the vertical direction of the projector device 2). Measure the distance to the distance measuring position. 3A shows a top view of the projector device 2 and the screen 1 as viewed from above, and FIG. 3B shows a side view of the projector device 2 and the screen 1 as viewed from the side. It is shown.

  The configuration of the imaging unit 31 will be described with reference to FIG. A line sensor 31c is disposed below the lens 31a that receives light incident from the outside and is separated by a focal length f. A line sensor 31d is disposed below the lens 31b by a focal distance f. These line sensors 31c and 31d are composed of a pair of line CCDs having a plurality of photodetecting elements arranged in a straight line or other line type image pickup elements. The configuration of the line sensors 31c and 31d will be described later in detail for convenience of explanation. For the image formed on the line sensors 31c and 31d via the lenses 31a and 31b, the imaging unit 31 serially outputs an electrical signal corresponding to the light amount of the image via an output unit (not shown). Note that the configuration of the imaging unit 41 is the same as that of the imaging unit 31, and thus the description thereof is omitted.

  The calculation unit 32 calculates a correlation value while sequentially shifting at least one of the pair of image signals output from the line sensors 31c and 31d over a predetermined shift range. Similarly, the calculation unit 42 calculates a correlation value while sequentially shifting at least one of the pair of image signals output from the line sensors 41c and 41d over a predetermined shift range.

  The control circuit 5 generates a control signal for correcting the tilt of the image by tilting the projected image based on the tilt angle in the rotation direction around the optical axis of the projection lens detected by the angle sensor 3. The image generation unit 6 is notified.

  Further, the control circuit 5 calculates the tilt angle of the screen 1 with respect to the first reference direction of the projector device 2 based on the distance calculation result of the first passive distance measuring device 30. Similarly, the tilt angle of the screen 1 with respect to the second reference direction of the projector device 2 is calculated based on the distance calculation result of the second passive distance measuring device 40. Based on the tilt angle information, the shape of the trapezoidal distortion is obtained, and a control signal for generating a trapezoidal distortion opposite to the image projected on the screen 1 is notified to the projected image generation unit 6.

  The projection image generation unit 6 inputs image data output from an image data output unit such as an external personal computer, registers it in a memory (not shown), and reads out the image data from the memory based on a control signal from the control circuit 5. Adjust timing. Specifically, when correcting the tilt of the projection image, the image is tilted in the rotation direction opposite to the rotation direction by the tilt angle in the rotation direction around the optical axis of the projection lens obtained by the angle sensor 3. The read timing of the image data from the memory is adjusted so that the projected image is generated.

  In addition, when correcting the trapezoidal distortion, the projection image generation unit 6 generates a black signal (no video signal) corresponding to the trapezoidal distortion at the start and end of data reading of one or more lines in the horizontal direction. The reading of image data from the memory is controlled so as to be inserted. In this way, image data having a trapezoidal distortion shape opposite to the trapezoidal distortion shape generated in the projection image is generated. Note that the process of thinning out image data so as to have a trapezoidal distortion shape opposite to the trapezoidal distortion shape is generally called keystone correction.

  The display drive unit 7 functions as an image distortion correction unit, and based on the tilt angles with respect to the first reference direction and the second reference direction calculated by the control circuit 5, a projection lens optical system including a condenser lens as a projection lens (not shown) 8 is adjusted to correct the trapezoidal distortion of the projected image. The display driving unit 7 functions as an autofocus unit that automatically adjusts the focus of a projection lens (not shown). The projection lens optical system 8 projects predetermined image light on the screen 1.

  Next, the operation principle of the first passive distance measuring device (external light triangular distance measuring method) 30 will be described with reference to FIG. FIG. 4 is a diagram showing a state in which the distance to the screen 1 is measured by the first passive distance measuring device 30. The operation principle of the second passive distance measuring device 40 is the same as that of the first passive distance measuring device 30, and thus the description thereof is omitted.

  In FIG. 4A, a pair of lenses 31a and 31b are arranged apart from each other by a predetermined baseline length a extending in the horizontal direction on a plane constituting the front surface of the projector device 2. A pair of line sensors 31c and 31d that are spaced apart from the pair of lenses 31a and 31b by their focal lengths f and extend in the direction of the baseline length a are disposed below the plane that forms the front surface of the projector device 2. Yes. The line sensors 31c and 31d are arranged so that the central portions thereof are substantially located on the optical axes 31ax and 31bx of the lenses 31a and 31b, respectively. On these line sensors 31c and 31d, an image T at a certain position on the screen 1 for distance measurement (ranging) is formed via the corresponding lenses 31a and 31b. In FIG. 4A, the measurement position T on the screen 1 is imaged on the line sensors 31c and 31d through the optical paths A and B in different directions and the respective lenses 31a and 31b. .

  Assuming that the measurement position T exists at an infinite position, the measurement position T is located on the line sensors 31c and 31d at the focal length f from the pair of lenses 31a and 31b, and the optical axes 31ax of the lenses 31a and 31b. And 31bx are imaged at reference positions 31cx and 31dx. Here, when the measurement position T approaches from the infinity position along the direction A on the optical axis 31ax of the lens 31a and reaches the position LC in FIG. 4A, that is, the distance LC from the lens 31a to the screen 1, the measurement position is reached. Although T is imaged on the reference position 31cx on the line sensor 31c, it is imaged on the line sensor 31d at a position shifted by a phase difference (deviation amount) α from the reference position 31dx by the lens 31b. Is done.

  At this time, from the principle of triangulation, the distance LC to the measurement position T is obtained by LC = af / α. Here, the base line length a and the focal length f are known values known in advance, and the distance LC can be measured by detecting the phase difference (shift amount) α from the reference position 31dx on the line sensor 31d. That is, the distance to the screen 1 can be detected. This is the operating principle of a passive line sensor distance measuring device for external light triangulation. The detection of the phase difference (shift amount) α and the calculation of LC = af / α are executed by the calculation unit 32 shown in FIG.

  Detection of the phase difference (shift amount) α from the reference position 31dx of the line sensor 31d is performed by detecting the partial image data group iLm extracted from the pair of image data signal sequences IL and IR output from the pair of line sensors 31c and 31d, respectively. iRn is detected by the calculation unit 32 performing a correlation calculation.

  An outline of the correlation calculation will be described. As shown in FIG. 4B, the correlation calculation is performed by using the line sensors 31c and 31d as the line sensors 31c and 31d for the regions where the degree of coincidence is highest when the partial image data groups iLm and iRn are superimposed on each other. This is a calculation that is detected while relatively shifting. In FIG. 4B, the position of the partial image data group iLm from one line sensor 31c is fixed to the reference position 31cx and used as the reference portion. The partial image data group iRn from the other line sensor 31d is shifted one pixel at a time as a reference portion, and the partial image data group iRn having the highest degree of coincidence with the reference portion is searched. The interval between the position on the line sensor 31d that generates the partial image data group iRn having the highest degree of coincidence and the reference position 31dx of the line sensor 31d is the phase difference (deviation amount) α.

  Since each of the line sensors 31c and 31d is composed of a pair of line CCDs in which a predetermined number of photodetecting elements (pixels) are arranged on a straight line having a predetermined length, the phase difference (shift amount) α is the partial image data. It can be easily obtained from the pixel position and pixel pitch in the image data signal sequence IR of the group iRn. In this way, the distance LC to the measurement position T in the same direction A as the optical axis 31ax of the lens 31a can be measured by detecting the phase difference (deviation amount) α.

  Next, the configuration of the line sensor will be described with reference to FIG. FIG. 5 shows a configuration of a line sensor when a pair of line sensors 31c and 31d detect distances in a plurality of directions. As shown in FIG. 5, by dividing the line sensors 31c and 31d into a plurality and setting a plurality of reference positions according to the distance measuring direction, it is possible to detect distances in a plurality of directions with one distance measuring device. That is, when distance measurement in a plurality of directions is performed by the pair of line sensors 31c and 31d, a plurality of distance measurement directions (R (right) and C (center in this example) are included in the line sensor 31c as shown in FIG. ), L (left)), a plurality of distance measurement calculation areas (31cR, 31cC, 31cL) corresponding to a plurality of reference positions are provided. Similarly, a plurality of ranging calculation areas (31dR, 31dC, 31dL) corresponding to a plurality of reference positions based on a plurality of ranging directions (R, C, L) are provided in the line sensor 31d. Then, the amount of deviation from the reference position can be obtained by using partial video data in a pair of distance measurement calculation areas (31cR and 31dR, 31cC and 31dC, 31cL and 31dL) corresponding to the distance measurement direction.

  The projector device 2 of the present embodiment includes an angle sensor 3 such as a gyro sensor, and the tilt angle in the rotation direction and the rotation direction (clockwise and counterclockwise) around the optical axis of the projection lens of the projector device 2 main body. Ask. For example, when the pedestal on which the projector device 2 is installed is tilted obliquely rather than horizontally, the projector device 2 itself is also tilted around the optical axis of the projection lens, and the image projected on the screen 1 is also tilted on the pedestal. It will be tilted accordingly.

  When the angle sensor 3 determines the tilt angle and the rotation direction in the rotation direction around the optical axis of the projection lens, the projection sensor is tilted in the rotation direction opposite to the calculated rotation direction by the same angle as the tilt angle. Generate an image. In the present invention, a projection image that is rotated about the optical axis of the projection lens by the same angle as the tilt angle is generated. A corrected image obtained by rotating the original image by a predetermined angle is projected onto the screen 1 by the projection lens optical system 8.

  The projection lens optical system 8 that projects an image is provided with a liquid crystal panel that changes light from the light source into image light corresponding to the image. The image is enlarged and displayed on the screen 1 by enlarging the image light from the liquid crystal panel with the projection lens. In this embodiment, when projecting an image, not using all the effective pixel area (maximum area) of the liquid crystal panel, but generating video light using only a part of the effective pixel area and projecting the image. To do. FIG. 6 shows a case where an image is projected using all of the effective pixel area (a region indicated by a dotted line in FIG. 6), and a case where an image is projected using a part of the effective pixel area (FIG. 6). The area of the projected image projected on the screen 1 is shown in (area indicated by a solid line). As described above, by using only a part of the effective pixel area of the liquid crystal panel, a reduced projection image is projected onto the screen 1.

  However, by projecting the image using only a part of the effective pixel area of the liquid crystal panel, when the image light of the corrected image obtained by rotating the original image by a predetermined angle is generated on the liquid crystal panel, the corrected image is There is no problem that a part of the image protrudes from the effective pixel area and cannot be projected onto the screen 1.

  FIG. 7A shows a projected image before correcting the inclination of the image. A region indicated by a dotted line in FIG. 7A indicates an image range projected on the screen 1 when the entire effective pixel area of the liquid crystal panel is used. In addition, an area indicated by a solid line in FIG. 7A shows an image range projected on the screen 1 when only a part of the effective pixel area of the liquid crystal panel is used. Such an image is rotated to correct the inclination of the image. FIGS. 7B and 7C show the corrected projection images. The area indicated by diagonal lines in FIG. 7B is projected onto the screen 1 when an image projected using all of the effective pixel area (area indicated by the dotted line in FIG. 7A) is rotated. Indicates the image range. An image that is not within the dotted line range of FIG. 7B cannot be displayed on the screen 1 because it is not within the effective pixel area of the liquid crystal panel. In addition, an area indicated by diagonal lines in FIG. 7C corresponds to the screen 1 when an image projected using a part of the effective pixel area (area indicated by a solid line in FIG. 7A) is rotated. The projected image range is shown. By using a part of the effective pixel area, all of the image is located in the effective pixel area and can be displayed even if the image is subjected to the rotation process.

  In this way, in the present embodiment, the angle sensor 3 is provided to detect the tilt angle of the projector device 2 itself, and the image is corrected based on the detected tilt angle so that the projected image has no tilt, and the image is projected. Thus, it is possible to automatically correct the inclination of the image.

  Next, the operation procedure of this embodiment will be described with reference to the flowchart shown in FIG. First, an image pattern for phase difference detection is projected on the screen 1 by the projection lens optical system 8 (step S1). An image pattern of white and black vertical stripes is used as the phase difference detection image so that the phase difference can be easily detected by the first passive distance measuring device 30 and the second passive distance measuring device 40. The reflected light of the phase difference detection image projected on the screen 1 is received by the first passive distance measuring device 30 and the second passive distance measuring device 40, and from the projector device 2 to a plurality of measurement positions on the screen 1. Is measured (step S2). Reflected light of the phase difference detection image is received by the line sensors 31c, 31d, 41c, and 41d, and deviations (phase differences) from the reference positions of the line sensors are detected by the calculation units 32 and 42, respectively. The distance to the object (measurement position on the screen 1) is measured. The calculation unit 32 performs a correlation calculation on the partial image data groups extracted from the pair of image data signal sequences output from the line sensors 31c and 31d, and detects the shift amount. Similarly, the calculation unit 42 performs a correlation calculation on the image data output from the line sensors 41c and 41d, and detects a deviation amount. The distance measurement data measured by the first passive distance measuring device 30 and the second passive distance measuring device 40 is transmitted to the control circuit 5.

Next, angle calculation is performed using distance measurement data (step S3). Using the distance measurement data of the first passive distance measuring device 30, an inclination angle θ1 with respect to the horizontal direction (first reference direction) of the screen 1 is obtained. Similarly, an inclination angle θ2 with respect to the vertical direction (second reference direction) of the screen 1 is obtained using distance measurement data of the second passive distance measuring device 40. Hereinafter, the angle calculation will be described by taking as an example a method of calculating the tilt angle θ1 of the screen 1 with respect to the first reference direction from the distance measurement data of the first passive distance measuring device 30. As shown in FIG. 9, the inclination angle of the screen 1 with respect to the first reference direction (horizontal direction of the projector device 2) of the first passive distance measuring device 30 is θ1, and the distance measurement calculation area 31cL is set to the distance measurement position 1A. The distance calculation result is L1, the distance calculation result for the distance measurement position 1B using the distance calculation area 31cR is L2, the distance between the distance measurement position 1A and the optical axis L is L1 ′, When the distance between the ranging position 1B and the optical axis L is L2 ′, the inclination angle θ1 is
tan θ1 = (L2−L1) / (L1 ′ + L2 ′)
Is required.

  Here, L1: L1 ′ = f: P (1a−k) holds due to the similarity of the triangles. When this is expanded, L1 '= PL1 (1a-k) / f. Here, 1a is the pixel number corresponding to the contrast centroid position of the distance measurement position 1A imaged in the distance calculation calculation area 31cL, k is the pixel number of the line sensor corresponding to the optical axis, P is the pixel pitch of the line sensor, f Is the focal length. Similarly, L2 'can be expressed by L2' = PL2 (1b-k) / f. Here, 1b is a pixel number corresponding to the contrast gravity center position of the distance measurement position 1B imaged in the distance measurement calculation area 31cR. P and f are constants obtained at the design stage and the like, and these values are stored in the control circuit 5 in advance. In addition, since the method for obtaining the contrast center-of-gravity position is a known technique (see, for example, JP-A-8-75985), the description thereof is omitted in this embodiment. A similar method can be applied to a method of calculating the inclination angle θ2 of the screen 1 with respect to the second reference direction based on the distance measurement data of the second passive distance measuring device 40.

  Next, trapezoidal distortion generated in the projected image is obtained from the obtained inclination angles θ1 and θ2 of the screen 1, and keystone correction is performed (step S4). The memory unit 10 records how much distortion occurs in the projected image due to the obtained tilt angles θ1 and θ2. The control circuit 5 refers to the memory unit 10 to obtain the trapezoidal distortion shape in the horizontal direction and the vertical direction, and generates image data having a trapezoidal distortion shape opposite to the obtained trapezoidal distortion shape.

  An example of generating an image for correcting trapezoidal distortion from an original image of N lines in the vertical direction and M lines in the horizontal direction will be described. FIG. 10A shows a trapezoidal distortion shape on the original image determined from the tilt angle, and FIG. 10B) shows a trapezoidal distortion shape opposite to the trapezoidal distortion shape shown in FIG. The converted original image is shown. From the information of the inclination angle, for example, as shown in FIG. 10A, it is determined that the image portion of the L-th line from the bottom is distorted to M-2p pixels, and the p pixels at both ends thereof are trapezoidal distortion and no image is displayed. Suppose that In this case, as shown in FIG. 10B, the control circuit 5 displays an image at the center M-2p pixel in the NL line from the bottom, and a black signal at the p pixel portions at both ends. A control signal is generated so that (or no signal) is displayed. In this way, image data having a trapezoidal distortion shape opposite to the trapezoidal distortion shape of the projection image is generated.

  Next, the angle sensor 3 is used to determine the tilt angle and the rotation direction (clockwise, counterclockwise) about the optical axis of the projection lens (step S5). When the pedestal on which the projector device 2 is installed is tilted obliquely rather than horizontally, the projector device 2 main body is also tilted around the optical axis of the projection lens.

  Next, the original image is rotated by the tilt angle obtained by the angle sensor 3 to generate a corrected image (step S6). A corrected image is generated by rotating in the rotation direction opposite to the rotation direction obtained by the angle sensor 3 by the tilt angle in the rotation direction around the optical axis of the projection lens. Projection light of the corrected image is generated by the liquid crystal panel, and the generated projection light is projected onto the screen 1 via the projection lens. In this embodiment, when projecting an image, not all the effective pixel area (maximum area) of the liquid crystal panel is used, but video light is generated using only a part of the effective pixel area, and the image is displayed on the screen 1. Is projected. For this reason, even if it is a corrected image obtained by rotating the original image by the tilt angle obtained by the angle sensor 3, the corrected image does not protrude from the effective pixel area of the liquid crystal panel, and the entire corrected image is displayed on the screen. 1 can be projected.

  Next, a second embodiment of the present invention will be described. In this embodiment, the inclination angle of the rotation direction around the optical axis of the projection lens obtained by the angle sensor 3 is compared with a predetermined value set in advance. The predetermined value is set to an angle at which the inclination of the image is not worrisome even if inclination correction is not performed (preferably 5 degrees or an angle before and after this). Such a predetermined value is compared with the inclination angle obtained by the angle sensor 3, and when the inclination angle is smaller than the predetermined value, the projection of the image performed using a part of the liquid crystal panel is performed. The entire effective pixel area is used. Note that the image projected on the screen 1 is an original image whose image tilt is not corrected. In this way, the present embodiment can enlarge and project a projected image when image tilt correction is not performed.

  The operation procedure of this embodiment is shown in the flowchart of FIG. As shown in the flowchart of FIG. 11, the angle sensor 3 obtains the rotation angle and rotation direction (clockwise, counterclockwise) about the optical axis of the projection lens (step S14), and the obtained inclination angle The predetermined value is compared (step S15). When the inclination angle is smaller than the predetermined value (step S15 / YES), the entire effective pixel area of the liquid crystal panel is used to enlarge the size of the projected image (step S17). Since other procedures are the same as those in the first embodiment, the description thereof is omitted.

  The embodiment described above 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. For example, in the above-described embodiment, the inclination of the image is corrected by correcting the rotation of the image. However, the inclination of the image may be corrected by adjusting the attitude of the projector device itself. In the above-described embodiment, when the image is rotated, the image does not have to be rotated about the optical axis of the projection lens.

It is a block diagram which shows the structure of the projector apparatus of an Example. It is a figure which shows the structure which looked at the projector apparatus from the front. (A) is a figure for demonstrating the inclination angle with respect to the horizontal direction of the screen 1, (B) is a figure for demonstrating the inclination angle with respect to the vertical direction of the screen 1. FIG. It is the figure which showed a mode that a screen distance-measures with a passive ranging device. It is a figure which shows the structure of a line sensor. It is the figure which showed the range of the image projected on the screen 1 when the use area of a liquid crystal panel is changed. (A) is a figure which shows the case where the inclination has arisen in the projection image, (B) is the image projected on a screen after rotation correction, when all the liquid crystal panels are used for the projection of an image. (C) is a diagram showing an image projected on the screen after the rotation correction when a part of the liquid crystal panel is used for projecting the image. 3 is a flowchart illustrating an operation procedure according to the first exemplary embodiment. It is a figure for demonstrating the calculation method of the inclination angle of the screen. It is a figure for demonstrating the method of correct | amending trapezoid distortion. 10 is a flowchart illustrating an operation procedure according to the second embodiment. It is a block diagram which shows the structure of the conventional projector apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screen 2 Projector apparatus 3 Angle sensor 5 Control circuit 6 Projection image production | generation part 7 Display drive part 8 Projection lens optical system 9 Optical system drive part 10 Memory part 20 Automatic focus detection apparatus 21 Light reception sensor 22 Calculation part 30 1st passive ranging Device 31 Imaging unit 31a, 31b Lens 31c, 31d Line sensor 32 Calculation unit 40 Second passive distance measuring device 41 Imaging unit 41a, 41b Lens 41c, 41d Line sensor 42 Calculation unit

Claims (5)

An angle detection means for detecting an inclination angle around the optical axis of the projection lens of the projector device;
And a control unit that corrects an inclination of the image projected on the screen around the optical axis of the projection lens based on the inclination angle detected by the angle detection unit. The control means, based on the tilt angle detected by the angle detection means and the rotation direction around the optical axis of the projection lens, displays the original image by the tilt angle in the rotation direction opposite to the rotation direction. The projector device according to claim 1, wherein an inclined image is generated. Image projection means for processing light from a light source into projection light corresponding to an image in a pixel area, and projecting image light from the pixel area onto a screen via a lens;
3. The projector according to claim 1, wherein when the image with the corrected tilt is projected onto the screen, the image is projected onto the screen using a part of the pixel area. The control means compares the inclination angle detected by the angle detection means with a predetermined threshold value. When the inclination angle is smaller than the predetermined threshold value, the control means uses all of the pixel area. The projector apparatus according to claim 3, wherein an image before tilt correction is projected onto the screen. A trapezoidal distortion correction step of measuring a distance to a screen to project an image, calculating a relative positional relationship between the screen and the projector device based on the distance information, and correcting a trapezoidal distortion of the projected image;
An inclination angle detection step of detecting an inclination angle around the projection lens of the projector device;
An image correction step of correcting an inclination of the image projected on the screen around the projection lens based on the inclination angle detected by the inclination angle detection step.

Images