JP2004109122A - Angle sensing device and projector equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angle sensing device and a projector of simplified configuration utilizing a line type passive auto-focusing device used on a camera, etc. <P>SOLUTION: In the device, a control circuit 5 computes a relatively horizontal tilt angle between a screen 1 and a projector 2 based on ranging operation results from the line type passive auto-focusing device 3, while computing a relatively vertical tilt angle between the screen 1 and the projector 2 based on ranging operation results from the line type passive auto-focusing device 4. Further a display driving section 7 adjusts a projection optical system 8 including a condenser lens to correct trapezoidal distortion of the projection image, based on both horizontal/vertical tilt angles and distance between ranging operational areas computed by the control circuit 5. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an angle detection device using a line-type passive distance measuring device and a projector including the same.

Conventionally, when a projector such as a liquid crystal projector is used, there is a problem that a distortion called trapezoidal distortion occurs in a projected image due to a positional relationship between the projector and the screen. As a technique for correcting the trapezoidal distortion, there is an electric correction method of generating an image having a trapezoidal distortion opposite to the projected image in a video circuit in the projector and projecting the image, and an image generated by the video circuit is not corrected. In general, there are two optical correction methods for adjusting the inclination of a condenser lens included in a projection optical system in a projector.

Conventional techniques for automatically correcting such trapezoidal distortion are described in JP-A-2000-122617, JP-A-2001-339671, and JP-A-2002-62842.

In the prior art described in Japanese Patent Application Laid-Open No. 2000-122617, a distance to a screen is detected by two active distance measurement sensors provided at different positions on the front of a liquid crystal projector, and the two detected distances and two distances are detected. The tilt angle of the liquid crystal projector with respect to the screen is calculated based on the distance between the distance sensors, and the trapezoidal distortion is corrected by the above-described method based on the calculated tilt angle.

In the related art described in Japanese Patent Application Laid-Open No. 2001-339671, an angle sensor circuit such as a gyro is provided in a projector or a screen, and trapezoidal distortion correction in the horizontal (left / right) direction and vertical ( It performs trapezoidal distortion correction in the vertical direction or combined trapezoidal distortion correction in the horizontal and vertical directions.

The prior art described in Japanese Patent Application Laid-Open No. 2002-62842 uses a camera to detect the position and tilt of the screen, and performs image processing on a screen image captured by the camera with a screen position detection unit to position the screen. And trapezoidal distortion are corrected in accordance with the detected position and inclination of the screen.
JP-A-2000-122617 (page 4, FIG. 1) JP 2001-339671 A (page 3, FIG. 1) JP-A-2002-62842 (page 10, FIG. 1)

The prior art described in Japanese Patent Application Laid-Open No. 2000-122617 uses a plurality of active distance measuring devices to detect the inclination angle of the liquid crystal projector with respect to the screen. Since the light emitting element is required, the configuration becomes large, and there is a problem that electric power for causing the light emitting element for distance measurement to emit light is required. In addition, the screen is located at a distance where the light from the light emitting element for distance measurement does not reach within the range where the projected image of the projector reaches, or the distance measuring light reflected by the screen becomes weak within the range where the projected image of the projector reaches. In such a case, there has been a problem that the distance measurement accuracy is reduced and the detection accuracy of the inclination angle of the liquid crystal projector with respect to the screen is deteriorated accordingly. Further, since only the vertical tilt angle can be detected, trapezoidal distortion caused by horizontal tilt cannot be corrected.

On the other hand, the prior art described in Japanese Patent Application Laid-Open No. 2001-339671 does not use an active distance measuring device and detects the horizontal and vertical inclination angles. However, since the angle sensors are provided on both the projector and the screen in order to detect the relative inclination angle between the projector and the screen, there has been a problem that the configuration becomes large.

The prior art described in Japanese Patent Application Laid-Open No. 2002-62842 uses a camera to detect the inclination angle of the liquid crystal projector with respect to the screen. Although the inconvenience that the configuration is increased by providing an angle sensor in both of them is solved, there is an inconvenience that a camera and a processing circuit for performing complicated image processing are required to detect the inclination angle.

An object of the present invention is to simplify the configuration of an angle detection device that does not use a light emitting element dedicated to angle detection and a projector including the same.

According to a first aspect of the present invention, a pair of lenses disposed apart from each other by a base line length, a first light receiving region on which one of a pair of images of a measurement object generated by the pair of lenses forms an image, and And a second light receiving area on which the other of the images is formed. A plurality of distance measurement calculation areas corresponding to a plurality of distance measuring directions are set in each of the first and second light receiving areas. A plurality of line sensors based on an output of the line sensor in the distance calculation area in the first light receiving area and an output of the line sensor in the distance measurement area in the second light receiving area; A line-type passive distance measuring device having a calculation unit for calculating a distance in the direction of the distance measurement; and two different measurement methods in calculation results obtained by the line-type passive distance measuring device performing the distance measurement in the plurality of distance-measuring directions. Calculation results for the distance direction and the above two distance measurement methods And a tilt angle calculation unit that calculates a tilt angle of the measurement object with respect to the base line length direction based on a value corresponding to a distance between the two distance measurement calculation areas in the first light receiving area corresponding to It is a detection device. According to such a configuration, it is possible to realize a simple inclination angle detecting device that can use a line-type passive distance measuring device used in a camera or the like.

In a second aspect based on the first aspect, a value corresponding to a distance between the two distance measurement calculation areas in the first light receiving area is set in the base line length direction of each of the two distance measurement calculation areas. And the distance of the center position. According to such a configuration, it is possible to easily detect a value corresponding to the distance between the two distance measurement calculation areas in the first light receiving area used for angle detection, thereby simplifying angle detection.

In a third aspect based on the first aspect, the value according to the distance between the two distance calculation areas in the first light receiving area is imaged on each of the two distance calculation areas. It is the distance of the position of the center of gravity of the contrast of the image. According to such a configuration, it is possible to perform angle detection that compensates for a slight shift in the distance measurement direction due to the contrast position of an image formed in each distance measurement calculation area, thereby improving the angle detection accuracy.

In the fourth invention, the measurement object is a screen on which an image is projected. According to such a configuration, the inclination angle of the screen with respect to the base line length direction can be detected.

A fifth invention is a projector for projecting an image formed based on an input video signal onto a screen, wherein the tilt angle detecting device and the image on the screen are calculated based on the tilt angle calculated by the tilt angle detecting device. And an image distortion correction unit that corrects the distortion. According to such a configuration, it is possible to realize image distortion according to a relative tilt angle between the projector and the screen with a simple configuration.

In a sixth aspect based on the fifth aspect, the plurality of line-type passive distance measuring devices having different base line length directions are different from each other, and the plurality of line-type passive distance-measuring devices are provided with a plurality of line-type passive distance measuring devices. When the plurality of line-type passive distance measuring devices measure the distance, a plurality of patterns corresponding to each base line length direction of the plurality of line-type passive distance measuring devices are provided. The prepared adjustment image is projected. According to such a configuration, it is possible to reduce the amount of adjustment image data and shorten the distance measurement time.

According to the present invention, there is provided a simple tilt angle detection device that can use a line-type passive distance measuring device used in a camera or the like, or a projector configuration that corrects trapezoidal distortion of a projected image according to a tilt angle with a screen. Simplification can be achieved.

Hereinafter, the best mode for carrying out the present invention will be described with reference to an embodiment shown in the drawings.

FIG. 1 is a diagram illustrating an example of a projector that detects an inclination angle between a screen 1 and a projector 2 and corrects trapezoidal distortion of an image projected on the screen 1 based on the detected inclination angle. 2 is a front view of FIG. Note that the tilt angle detection device is not limited to one provided in the projector, nor is it limited to one that detects a tilt angle with the screen.

In FIG. 1, a first line-type passive distance measuring device 3 forms a pair of images of a screen 1 as a measurement target by a pair of lenses 31a and 31b and a pair of lenses 31a and 31b shown in FIG. An image pickup unit 31 including a pair of line sensors 31c and 31d, which will be described later, as a first line sensor for imaging, and a calculation for performing distance measurement calculation in a plurality of different directions based on the outputs of the pair of line sensors 31c and 31d. And a unit 32 for detecting the distance to the screen 1 at a plurality of points in the horizontal (left / right) direction. The pair of lenses 31a and 31b are arranged horizontally apart by a first base line length b.

The second line-type passive distance measuring device 4 serves as a second line sensor in which a pair of images of the screen 1 is formed by the pair of lenses 41a and 41b and the pair of lenses 41a and 41b shown in FIG. The screen 1 includes an imaging unit 41 provided with a pair of line sensors 41c and 41d, which will be described later, and a calculation unit 42 that performs distance measurement calculation in a plurality of different directions based on outputs of the pair of line sensors 41c and 41d. Is detected at multiple points in the vertical (up / down) direction. The pair of lenses 41a and 41b are vertically separated by a second base line length b '.

The control circuit 5 as the first and second tilt angle calculation units performs various controls and calculations. For example, the screen 1 and the projector 2 (the first baseline) are calculated based on the distance measurement calculation results of the line-type passive distance measuring device 3. Relative to the screen 1 and the projector 2 (second base line length direction) based on the distance calculation result of the line-type passive distance measuring device 4. Calculate the vertical tilt angle.

The projection image generation unit 6 receives image data output from an image data output unit such as an external personal computer, converts the input image data into display data, and outputs the display data to the display drive unit 7.

The display drive unit 7 as the image distortion correction unit adjusts the projection optical system 8 including the condenser lens based on the horizontal and vertical inclination angles calculated by the control circuit 5 to correct the trapezoidal distortion of the projected image.

Next, the operation principle of the line type passive distance measuring device (external light triangulation method) 3, 4 will be described with reference to FIG. Note that the line-type passive distance measuring device 3 and the line-type passive distance measuring device 4 are installed at different angles, but have the same configuration. Therefore, in order to simplify the description, in this example, only the line-type passive distance measuring device 3 is used. explain. To explain the correspondence of the configuration, the pair of lenses 41a and 41b of the line-type passive distance measuring device 4 correspond to the pair of lenses 31a and 31b of the line-type passive distance measuring device 3, and the line-type passive distance measuring device 3 is used. The pair of line sensors 41c and 41d of the device 4 correspond to the pair of line sensors 31c and 31d of the line-type passive distance measuring device 3, and the imaging unit 41 of the line-type passive distance measuring device 4 has a line-type passive distance measuring device. The arithmetic unit 42 of the line-type passive distance measuring device 4 corresponds to the arithmetic unit 32 of the line-type passive distance measuring device 3.

In the figure, a pair of lenses 31a and 31b are arranged at a predetermined base line length b apart, and a pair of optical sensor arrays arranged at a focal length f from the pair of lenses 31a and 31b. An image of the measurement object (screen) 1 is formed on each of 31c and 31d via different optical paths 1A and 1B. It is assumed that the measurement target 1 exists at a position separated by a distance LC in the front direction from the pair of lenses 31a and 31b.

When the measurement object 1 is at a position at infinity, the center of the image formed on the pair of optical sensor arrays 31c and 31d is at the reference position (corresponding to the optical axis of the lenses 31a and 31b on the optical sensor arrays 31c and 31d). 31c1 and 31d1), the image is formed at a position shifted from the reference positions (31c1 and 31d1) by α when the measurement target 1 approaches the infinity position. From the principle of triangulation, the distance LC to the object 1 is LC = bf / α. Here, since the base line length b and the focal length f are constants, the distance LC can be measured by detecting the shift amount α. This is the operation principle of the passive type distance measuring device of the external light triangulation, and the arithmetic unit 32 performs this calculation.

The deviation amount α from the reference position is shown in FIG. 1 for the partial video data groups iL and iR extracted from the pair of video signals (video data strings) IL and IR output from the pair of line sensors 31c and 31d, respectively. The calculation unit 32 performs the correlation calculation to detect the correlation. Since the correlation calculation is well known, a detailed description thereof will be omitted, but in general, as shown in FIG. 3B, an area having the highest matching degree when the partial video data groups iL and iR are superimposed is defined as This is an operation of detecting overlapping partial video data groups iL and iR while relatively shifting them in the direction in which the optical sensor arrays are arranged.

When performing the correlation calculation, as shown in FIG. 3B, one of the partial video data groups iL is fixed as a reference portion according to a reference position, and the other partial video data group iR is shifted as a reference portion. Accordingly, the optical axis direction of the lens 31a can be set as the distance measurement direction. However, when the distance measurement direction is a direction from the center position of both lenses, one partial video data group iL and the other partial video data group iR may be relatively shifted.

Next, the principle of distance measurement of the line-type passive distance measuring apparatus in the case where the direction different from the front is set as the distance measuring direction will be described with reference to FIG.

In the figure, when the center of the image formed on the pair of optical sensor arrays 31c and 31d is the reference position (31c2, 31d2) when the measurement object 1 is located at infinity in the direction C to be measured, the measurement is performed. When the measurement target 1 approaches the infinity position in the distance direction C, an image of the measurement target 1 is formed at a position shifted from the reference positions (31c2, 31d2) by α. From the principle of triangulation, the distance LR to the measurement target 1 is LR = bf / (αcosβ). The angle β is the inclination angle of the distance measurement direction C with respect to the perpendicular A of the base line, and is an angle determined by determining the measurement direction C. Here, since the base line length b, the focal length f, and the cos β are constants, the distance LR can be measured by detecting the shift amount α. This is the distance measurement principle when the direction different from the front is the distance measurement direction.

Further, the distance LR ′ from the straight line having the extended base line length to the measurement target 1 is LR ′ = LRcosβ = bf / α, and the distance LR ′ can be measured by detecting the shift amount α in the same manner as described above. The angle β is not required for the calculation.

Also in this case, when performing the correlation calculation, one partial video data group iL is fixed as a reference portion and the other partial video data group iR is shifted as a reference portion as shown in FIG. 4B. The direction C shifted by an angle β with respect to the optical axis of the lens 31a can be set as the distance measurement direction. Therefore, by setting a plurality of reference positions in accordance with the ranging direction, it is possible to detect distances in a plurality of directions with one line-type passive ranging device.

In this example, the relative inclination angle between the screen 1 and the projector 2 is detected by using the line-type passive distance measuring devices 3 and 4.

When performing distance measurement in a plurality of directions with one line-type passive distance measurement device, as shown in FIG. 5, a plurality of distance measurement directions (R (right), C ( A plurality of distance measurement calculation areas (31cR, 31cC, 31cL) corresponding to a plurality of reference positions based on L (left) and L (left) are provided, and a plurality of distance measurement directions (R, C) are provided in the line sensor 31d. , L), a plurality of distance measurement calculation areas (31dR, 31dC, 31dL) corresponding to a plurality of reference positions, and a pair of distance measurement calculation areas (31cR and 31dR, 31cC and 31dC, The deviation amount from the reference position is obtained by using the partial video data in (31cL and 31dL). In this example, the distance measuring directions are three directions of R (right), C (center), and L (left), but the distance measuring direction is not limited to these, and can be changed as appropriate.

Next, the operation will be described.

When a power source or the like is turned on, the control circuit 5 determines whether or not image data has been input. If image data has been input, the control circuit 5 causes the projection image generation unit 6 to output display data corresponding to the image data. An image is projected on the screen 1 via the display driving unit 7 and the projection optical system 8, and if there is no input of image data, the adjustment contrast image data stored in the control circuit 5 in advance is output to the projection image generating unit. 6 and an image corresponding to the data is projected on the screen 1 as shown in FIG. This operation is an operation for displaying an image with contrast on the screen 1 in order to prevent deterioration of the ranging accuracy of the line-type passive ranging devices 3 and 4. As described above, light projection for preventing deterioration of the distance measurement accuracy (inclination angle detection) of the line-type passive distance measurement devices 3 and 4 is performed by using the image projection function originally provided in the projector. Is unnecessary, and the configuration can be simplified. In addition, since the distance is measured based on the image projection, the distance that can be measured depends on the distance that can be projected. Therefore, there is no need to match the distance measurement limit distance and the projection limit distance.

Here, the contrast image for adjustment will be described with reference to FIG. The adjustment contrast image 100 includes a horizontal pattern 101 for calculating a distance to the screen 1 using the line-type passive distance measuring device 3 and a distance to the screen 1 using the line-type passive distance measuring device 4. And a vertical direction pattern 102 for performing the patterning. The patterns 101 and 102 are arranged so as to be orthogonal to each other to form a cross-shaped pattern. The horizontal pattern 101 has a high-contrast shape in which two rectangular black patterns having different widths are alternately arranged in the first base line length direction, and the line-type passive distance measuring device 3 is highly accurate. Phase difference can be detected. Similarly, the vertical pattern 102 has a high-contrast shape in which two rectangular black patterns having different widths are alternately arranged in the second base line length direction. The phase difference can be detected with high accuracy. As described above, since the adjustment contrast image 100 includes the horizontal pattern 101 and the vertical pattern 102 used when the distance to the screen 1 is measured by the distance measurement devices 3 and 4, the adjustment contrast image 100 is provided. Can be reduced, and the distance measurement time can be shortened by simultaneously performing the distance measurement operations of the distance measurement devices 3 and 4.

Note that the adjustment contrast image 100 is not limited to the cross-shaped pattern shown in FIG. 12, and for example, a horizontal pattern 101 and a vertical pattern 102 are arranged so as to be orthogonal to each other as shown in FIG. It may be a T-shaped pattern or an L-shaped pattern. Further, the number and the color of the rectangular patterns having different widths constituting the horizontal pattern 101 and the vertical pattern 102 are not limited to the above, and can be appropriately changed as long as the pattern has a high contrast. Further, in this example, as shown in FIG. 12, although the horizontal pattern 101 and the vertical pattern 102 have different widths, the areas of the patterns differ from each other, but the areas of the respective patterns may be the same.

Next, the control circuit 5 operates the line-type passive distance measuring devices 3 and 4 to cause each of them to detect the distance to the screen 1 in a plurality of directions.

The control circuit 5 calculates a relative horizontal (first base line length) inclination angle between the screen 1 and the projector 2 based on the distance measurement calculation result of the line-type passive distance measurement device 3, and also controls the line-type passive distance measurement. The relative inclination angle of the screen 1 and the projector 2 in the vertical direction (second base line length direction) is calculated based on the distance measurement calculation result of the distance measurement device 4.

FIGS. 6 to 10 are diagrams for explaining an example of the above-described calculation of the inclination angle. Note that this example includes detection of a tilt angle in the horizontal (left / right) direction, detection of a tilt angle in the vertical (up / down) direction, or detection of a combined tilt angle in the horizontal and vertical directions. For the sake of understanding, hereinafter, detection of a horizontal inclination angle using the line-type passive distance measuring device 3 will be described.

FIG. 6 is a diagram for explaining the advance adjustment processing of the line-type passive distance measuring device 3 in the projector. If the line-type passive distance measuring device 3 used in the present example sets the direction different from the front as the distance measuring direction, the distance measuring operation results in the distance from the straight line with the extended base line length to the measurement target 1 instead of the original distance. (In the example of FIG. 4, LR ′ is output instead of LR). Therefore, when measuring objects 1D, 1E, and 1F on the chart 1 parallel to the base line length b direction as shown in FIG. 6, ideally, the distance measurement results (positions) of the measuring objects 1D, 1E, and 1F are obtained. Phase difference) should be the same, but in practice, the same result is unlikely to be obtained due to the influence of aberrations in the respective distance measurement calculation areas. Therefore, in this example, a correction coefficient for making these calculation results identical is calculated in advance for each distance measurement direction, and the correction coefficient is stored in an EEPROM or the like in the calculation unit, and is used for the distance measurement calculation. In addition, the correction coefficient is used to correct the variation in the calculation result of the distance measurement. Therefore, when the distance to the measurement target 1 on a straight line parallel to the base line length b direction is measured, the same calculation result is obtained regardless of the distance measurement direction (distance measurement calculation area), that is, the straight line obtained by extending the base line length. The distance to the measurement object 1 can be obtained.

FIG. 7 shows a screen 1 tilted by an angle (tilt angle) θ1 with respect to the base line length b direction (horizontal direction of the projector 2) using the line-type passive distance measuring device 3 adjusted as described above. An example of a case where the distance is calculated is shown. The distance calculation result when the distance calculation region 31cR is used is LR ', and the distance measurement result when the distance calculation region 31cL is used is LL'. A straight line passing through the ranging point 1D and parallel to the base line length b is denoted by b1, a straight line passing through the ranging point 1F on the screen 1 and parallel to the base line length b is denoted by b2, and a line perpendicular to the straight line b1 passing through the ranging point 1F. The intersection between the straight line b1 is G, the intersection between the ranging direction R and the straight line b1 is H, the intersection between the perpendicular line of the straight line b1 passing through the point H and the screen 1 is 1I, and the distance between the ranging calculation areas 31cR and 31cL is D is the distance. In this example, the intersection between the distance measurement direction R and the distance measurement calculation area 31cR is 31cR1, the intersection between the distance measurement direction L and the distance measurement calculation area 31cL is 31cL1, and the distance between the points 31cR1 and 31cL1 is set. The distance is D.

に お い て In such a situation, the distance between the ranging point 1F and the point G is LR'-LL '. That is, it is the difference between the distance LR 'and the distance LL'.

Here, as shown in FIG. 8, when the angle θ1 is small, it is noted that the distance between the ranging point 1F and the point G and the distance between the point H and the point 1I are substantially equal. The distance between them is approximately equal to LR'-LL '. Here, the angle θ1 is the inclination angle between the projector 2 and the screen 1 in the present embodiment, and it is unlikely that the angle θ1 becomes too large from the viewpoint of projecting the image projected by the projector 2 on the screen 1, so that the angle θ1 is not practically used. Even if it is assumed that the distance between H and the point 1I is LR'-LL ', there is no big problem. For example, in a case where the portable projector 2 is projected on the screen 1, the user installs the projector. Therefore, it is considered that the general adjustment of the angle between the two is usually performed by the installation of the user.

Also, as shown in FIG. 9, the distance measuring point 1D, the point H, and the triangle formed by the center of the lens 31a and the point 31cR1, the point 31cL1, and the triangle formed by the center of the lens 31a are similar. The distance from H is LL'D / f.

Therefore, as shown in FIG. 10, the inclination angle θ1 from the right triangle formed by the distance measuring point 1D, the point H, and the point 1I is:
θ1 = arctan ((LR′−LL ′) / (LL′D / f))
Can be obtained from

In the above description, the distance between the point 31cR1 and the point 31cL1 is used as the distance D between the distance measurement calculation areas 31cR and 31cL. However, for example, the center position of the distance measurement calculation area 31cR in the base line length direction and the distance measurement are used. The distance between the center positions in the base line length direction of the calculation region 31cL may be used. In this case, it is not necessary to detect the intersection with the distance measurement direction in the distance measurement calculation area, and a value corresponding to the distance between the two distance measurement calculation areas used for angle detection can be easily detected. Simplification can be achieved.

If high accuracy is required for angle detection, the distance between the center of gravity of the contrast in each distance measurement calculation area may be used as a value corresponding to the distance between the two distance measurement calculation areas used for angle detection. Good. Hereinafter, an example of this case will be described with reference to FIG.

As is well known, passive ranging includes an operation of detecting a state in which the degree of coincidence is highest when a pair of images are superimposed. However, this degree of coincidence is determined when the contrast state of the pair of images matches. It is to detect whether or not there is.

Therefore, in the case of the passive distance measurement, as shown in FIG. 11, even when a design distance measurement direction of one certain distance measurement calculation area 31cn is the direction of the arrow J, an image is formed on the distance measurement calculation area 31cn. When the image of the distance measurement target 1 is an image in which the contrast position 1K exists only in the direction of the arrow K, the actual distance measurement direction is shifted from the direction of the arrow J in the direction of the arrow K, and the distance measurement is formed in the distance measurement calculation area 31cn. If the image of the object 1 is an image in which the contrast position 1M exists only in the direction of the arrow M, the actual distance measurement direction is shifted from the direction of the arrow J in the direction of the arrow M. When the image of the distance measurement target 1 formed in the distance measurement calculation area 31cn is an image in which the contrast positions 1K and 1M exist in the arrow K direction and the arrow M direction, the actual distance measurement direction is measured from the arrow J direction. The image formed on the distance calculation area 31cn is shifted to the position of the center of gravity of the contrast.

Therefore, by using the distance of the position of the center of gravity of the contrast in each of the distance measurement calculation areas as a value corresponding to the distance between the two distance measurement calculation areas used for angle detection, a highly accurate distance D can be used. The angle detection accuracy is improved. A method of obtaining the position of the center of gravity of the contrast is known from Japanese Patent Application Laid-Open No. 8-75985. For reference, in this example, it is obtained from the following Equation 1.

In this example, serial numbers are given to the light receiving elements arranged in a line in the line sensor 31c.

As described above, it is possible to realize a simple inclination angle detecting device using a line-type passive distance measuring device used in a camera or the like.

When the inclination angles θ1 and θ2 are obtained, the control circuit 5 outputs the obtained inclination angles θ1 and θ2 to the display drive unit 7, and the display drive unit 7 calculates the inclination angles in the horizontal and vertical directions calculated by the control circuit 5. Based on this, the projection optical system 8 including the condenser lens is adjusted to correct the trapezoidal distortion of the projected image.

In the present embodiment, the projection optical system 8 including the condenser lens is adjusted based on the horizontal and vertical inclination angles calculated by the control circuit 5 to optically correct the trapezoidal distortion of the projected image. Based on the horizontal and vertical tilt angles calculated by the control circuit 5 in the projection image generation unit 6, display data of an image having a trapezoidal distortion opposite to the projection video is generated, and the trapezoidal distortion of the projection image is electrically determined. The correction may be made.

As described above, the image distortion corresponding to the relative tilt angle between the projector and the screen can be realized with a simple configuration using a line-type passive distance measuring device used in a camera or the like.

When the inclination angles θ1 and θ2 are obtained, the control circuit 5 stops the operation of the line-type passive distance measuring devices 3 and 4, and ends the angle detection operation and the trapezoidal distortion correction operation.

The control circuit 5 operates the line-type passive distance measuring devices 3 and 4 again after a predetermined time has elapsed after obtaining the inclination angles θ1 and θ2 once, and detects the inclination angles θ1 and θ2 again. The trapezoidal distortion correction operation may be performed again based on the tilt angles θ1 and θ2. With this configuration, since the image distortion is intermittently corrected, even if the installation state of the screen or the projector changes, the distortion correction according to the change can be automatically performed.

In the above example, two line-type passive distance measuring devices are used to detect inclination angles in a plurality of different directions, and trapezoidal distortion correction is performed based on each detection result. An inclination angle in one direction may be detected using a passive distance measuring device, and trapezoidal distortion correction may be performed based on the detected one inclination angle.

Further, in the above example, two line-type passive distance measuring devices detect inclination angles in two directions, that is, a vertical direction and a horizontal direction, as a plurality of different directions. The present invention is not limited to this, and can be changed as appropriate.

In the above description, the measurement target is a screen, but the measurement target is not limited to the screen, and can be changed as appropriate.

The present invention is not limited to the above-described embodiment, but can be appropriately modified and implemented without changing the gist.

FIG. 2 is a block diagram showing one embodiment of the present invention. The front view of FIG. FIG. 2 is a diagram showing a principle of distance measurement of the line-type passive distance measurement device of FIG. FIG. 2 is a diagram showing a principle of distance measurement of the line-type passive distance measurement device of FIG. FIG. 7 is a diagram showing a plurality of distance measurement calculation areas of a pair of line sensors 31c and 31d of the present example. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram showing a method of detecting an inclination angle in FIG. 1. FIG. 2 is a diagram illustrating an adjustment contrast image used for distance measurement by the line-type passive distance measurement device in FIG. 1. FIG. 2 is a diagram illustrating an adjustment contrast image used for distance measurement by the line-type passive distance measurement device in FIG. 1.

Explanation of reference numerals

3 first line-type passive ranging device 31a, 31b first pair of lenses 31c, 31d first line sensor 32 first calculating unit 4 second line-type passive ranging device 41a, 41b second One pair of lenses 41c, 41d Second line sensor 42 Second calculation unit 5 First and second tilt angle calculation unit 6 Image distortion correction unit 7 Image distortion correction unit

Claims (6)

A pair of lenses arranged apart from each other by a base length, a first light receiving region where one of a pair of images of a measurement object generated by the pair of lenses is formed, and the other of the pair of images is formed. A line sensor having a second light receiving area for imaging, wherein a plurality of distance measurement calculation areas corresponding to a plurality of distance measurement directions are set in each of the first and second light receiving areas; Based on the output of the line sensor in the distance measurement calculation area in the first light receiving area and the output of the line sensor in the distance measurement calculation area in the second light reception area, measurement is performed in the plurality of distance measurement directions. A line-type passive distance measuring device having a calculating unit for calculating a distance,
In the first light receiving area corresponding to the two different distance measurement directions, the calculation results for the two different distance measurement directions in the calculation results obtained by the line-type passive distance measurement device performing the distance measurement for the plurality of distance measurement directions. A tilt angle calculation unit that calculates a tilt angle of the measurement target with respect to the base line length direction based on a value corresponding to a distance between the two distance measurement calculation areas. 2. The distance according to claim 1, wherein the value corresponding to the distance between the two distance measurement calculation areas in the first light receiving area is the distance between the center positions of the two distance measurement calculation areas in the base line length direction. An angle detection device characterized by the above-mentioned. 2. The distance according to claim 1, wherein a value corresponding to a distance between the two distance measurement calculation areas in the first light receiving area is a distance of a contrast centroid position of an image formed in each of the two distance measurement calculation areas. An angle detection device, characterized in that: The angle detection device according to claim 1, wherein the measurement target is a screen on which an image is projected. A projector for projecting an image formed on the basis of an input video signal onto a screen, wherein the angle of the image on the screen is corrected based on the inclination angle calculated by the angle detection apparatus according to claim 4. A projector comprising an image distortion correction unit. 6. The angle according to claim 5, wherein a plurality of line-type passive distance measuring devices having different base line length directions and an inclination angle of the screen in a plurality of directions are calculated based on calculation results of the plurality of line-type passive distance measuring devices. A plurality of line-type passive distance-measuring devices projecting an adjustment image having a plurality of patterns corresponding to respective base line length directions of the plurality of line-type passive distance-measuring devices when measuring the distance. A projector characterized in that: