JP2004260785A - Projector with distortion correction function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which automatically performs correction in an oblique direction to a screen with ease. <P>SOLUTION: The projector comprises an image capture unit 6 which obtains an image picked-up by an image sensor 5, an image sensor optical distortion correction circuit 33 to correct the optical distortion of the image sensor, a projection display position detection unit 7 to detect the display position of a projected video in the image, a screen position detection unit 8 to detect the screen position in the image, a projection display image whole position calculation unit 41 to calculate the whole position of the projection display image according the projection display position detection unit 7, a screen distortion detection unit 9 to detect the distortion on the screen from a relative position of the screen position detection unit 8 and the projection display image whole position calculation unit 41. The projector also has a video input unit 10 for inputting the video to be projected by the projector, an image distortion correction circuit 11 for correcting the distortion according to the screen distortion detection unit 9, a display device driving circuit 12 for displaying the image from the image distortion correction circuit 11 on a display device 2. The projector is further provided with a display pattern generation unit 23 for generating a projection display position detection pattern for the projection display position detection unit 7. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a projection display device (hereinafter, referred to as a projector device), and particularly to a projector device having an automatic image distortion correction function.

  Regarding image distortion correction that occurs when the screen is not directly facing the projector device in the projector device, the distortion correction means is described in the specification of Japanese Patent Application No. 2002-018407.

  Conventionally, trapezoidal distortion caused by tilt projection of an image is generally processed only in the vertical direction, and the projector is installed at a position facing the screen in the horizontal direction.

  However, in recent years, a horizontal keystone distortion correction function has appeared, and vertical, horizontal, and oblique corrections have become possible.

  Among them, the correction method for the screen is still manually dependent, and it is easy to manually correct trapezoidal distortion only in the vertical or horizontal direction, but it can be corrected in the diagonal direction. For the distortion correction, it has been very difficult to correct the distortion.

  As a conventional technique, there is a projection-type lattice display device that corrects distortion of a projected image when an image is projected with a projection optical axis inclined with respect to a screen (for example, see Patent Document 1).

  Further, there is a projector device which can automatically provide distortion correction in an oblique direction by providing an image taken from a viewpoint different from that of a projector (for example, see Patent Documents 2 and 3).

  Further, there is a projector device capable of detecting a distance from a projection lens to a screen, calculating an inclination angle from the detection result, and automatically providing distortion correction (for example, see Patent Documents 4, 5, and 6). ).

Further, as a method of binarizing brightness data of a captured image, there is a method of determining a threshold for binarization from a histogram of the entire image, and for example, there is a method of determining a threshold by a method of discriminant analysis (for example, Non-Patent Document 1).
JP 2002-44571 A JP 2001-83949 A JP 2001-169221 A JP-A-4-355740 JP-A-2000-81593 JP 2000-122617 A Otsu, "Automatic threshold selection method based on discrimination and least square criterion", IEICE Transactions, Vol. J63-D, No. 4, p. 349-356

  However, the above-described conventional technology does not employ a method in which a distance measuring device is provided independently of the original function of the projector and a projected image is used. Further, in order to measure distances at a plurality of positions, a plurality of distance measuring devices are required.

  Further, the relative positional relationship with the projected image is not shown. The projected image greatly changes its position and screen size depending on the state of the projection lens. Therefore, simply measuring the positional relationship between the projector and the screen alone makes a correction suitable for the image actually being projected. It is unknown.

  Also, the position at which the measurement is being performed cannot be accurately indicated due to an installation error of the distance measuring device, a variation in the mechanical positional relationship between the projection lens and the display device, and the like.

  In addition, the measurement position of the distance measuring device and the screen position do not always coincide with each other, such as when a frame or the like exists immediately outside the screen and protrudes forward, or when the screen itself is recessed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a projector device that can automatically and automatically provide correction in an oblique direction with respect to distortion of an image projected and displayed on a screen.

  The present invention relates to a projector configured by a dot matrix, which projects a display device on a screen by enlarging and projecting the display device, and detects a position of the screen with respect to a projected image display range when the screen is projected in a state where the screen is not directly facing the projector. Then, image distortion correction is performed so that the projected image fits on the screen.

  A two-dimensional image sensor (camera) is used for screen detection.

  The position of the entire projection image is calibrated in advance so as to correspond to the two-dimensional detection position (horizontal and vertical directions) of the image sensor.

  The position of the entire projected image on the image sensor is compared with the position of the screen, and image distortion correction is performed so that the display on the display device fits in the position of the screen.

  According to the present invention, the processing from the capture of the image sensor to the calculation of the distortion correction data to the image distortion correction circuit can be performed by the internal calculation of the CPU.

  Until now, a similar correction function has been proposed for a system that can be provided by providing an image taken from a viewpoint different from that of a projector. Alternatively, by arranging the image sensors in such a positional relationship as to be integrated, the image sensors can be built in the projector, and the object function of the present invention can be achieved by the device alone.

  Further, the present invention relates to a projector configured by a dot matrix, which projects a display device on a screen by enlarging and projecting the display device. The distance to the corner is detected, the tilt angle of the projected image is calculated from the difference between the distances, the image distortion is detected, and the inverse correction is performed to perform image distortion correction.

  A two-dimensional image sensor (camera) is used for screen detection.

  However, if the distance from the projection lens to the surface on which the image is displayed to the four corners of the rectangle can be known without using a two-dimensional image sensor, the correction can be performed by the same means. An example of this means will also be given.

  In order to detect the distance from the projection lens to the four corners or a portion close to the four corners on the display screen using a two-dimensional image sensor, a rotation position detection sensor is mounted on the focus adjustment mechanism of the projection lens. The distance between the rotational position detection sensor and the focused projection lens is detected and stored in advance by a calibration operation. At the position where the optical focus is achieved, the image displayed on the display device is projected and displayed without blur on the display state of the screen. Conversely, at a position where the focus is not focused, the image is displayed out of focus. When the two-dimensional image sensor captures this display image, the contrast of the captured image is maximized at the position where focus is achieved. By detecting the position where the contrast becomes maximum, the position where the focus is achieved can be detected.

  The distance from the projection lens to the screen can be known by using the signal from the rotation position detection sensor mounted on the furcus adjustment mechanism at the position where the focus is achieved, and the data of the distance from the projection lens detected and stored in advance. be able to.

  In order to know the focus position, an image in which focus detection can be easily performed is displayed on the display device in advance, so that the focus adjustment operation can be effectively assisted.

  The two-dimensional image sensor can image up to the four corners on the projected screen. For example, by rotating the focus adjustment mechanism over the entire adjustment range, the focus positions at the four corners on the screen can be set. You can know at the same time.

  By the above operation, the distance from the projection lens to the four corners of the screen can be known, and as a result, it is possible to detect how much the projector and the screen are tilted from the directly-facing position. The image distortion is automatically corrected by reversely correcting the image distortion.

  Also, the present invention is a projector device comprising means for displaying a pattern on a screen to detect the position thereof, and calculating the position of the entire projection display screen of the projector from the position, and displaying the pattern on the screen. By detecting the position and calculating the position of the entire projection display screen from the position, the position of the entire projection display screen can be accurately detected even when the image sensor is located farther than the projection lens. Can be done.

  Further, in the projector device according to the present invention, by providing a means for correcting the optical distortion of the image sensor, the position of the entire projection display screen is accurately calculated from the position of the pattern on the screen even if there is optical distortion of the image sensor. Therefore, the relative position between the screen position and the entire position of the projection display screen can be accurately obtained.

  Furthermore, even when it is difficult to directly determine the optical distortion, the position of the projection display screen on which the image distortion correction was once performed is detected, and the image distortion correction is updated by comparing with the screen position to perform the image distortion correction. The apparatus is provided with a means capable of controlling the position of the projection display screen so as to match the screen position.

  For image distortion correction, the means for correcting the distortion are described in the specification of Japanese Patent Application No. 2002-018407, and for the automation of image distortion correction, the means for automatically correcting the distortion is described in the specification of the present invention. However, the present invention provides a method for correcting image distortion that occurs when the screen is not directly facing the projector device in the projector device.

  In the present invention, when projection is performed on an object that cannot be completely covered by the image distortion correction automated by the above means, the test pattern and the like used for the automatic image distortion correction are diverted as they are, and manual correction is performed. It is possible.

  This provides a means for performing a distortion correction operation without delay on an automatic (impossible) → manual user interface in response to an attempt to perform image distortion.

  The present invention has the following effects.

  Conventionally, when the screen is not directly opposed to the projector, so-called trapezoidal distortion correction has been manually adjusted or corrected by detecting the inclination of the projector.

  By using the projector device of the present invention, an image to be displayed is automatically displayed in a form conforming to the display surface of the screen. There is an effect that it looks as if a normal image is displayed.

  In addition, by using the projector device of the present invention, the tilt of the screen can be detected, and the displayed image is automatically corrected to a shape corresponding to the tilt of the screen. There is an effect that the displayed image can be observed as an image without distortion that matches the aspect ratio.

  In addition, by using the projector device of the present invention, the tilt of the screen can be detected, and the displayed image is automatically corrected to a shape corresponding to the tilt of the screen. There is an effect that the displayed image can be observed as an image without distortion that matches the aspect ratio.

  In the distance measuring method of the present invention, one image sensor, a projected image (using a function of projecting an image, which is a basic function of the device), a focus point, and a focus in the projection lens are used as the distance measuring device. It can be detected by using the position. As can be seen from the above, the configuration as the distance measuring device is made in a form utilizing the original function of the projector device, and is different from the conventional technology which can be used separately. Additional functions as a distance measuring device are a focus position sensor (position sensor using a variable resistor) added to the lens, a test pattern generation circuit, and a single image sensor. Since three or more distance measurements are required for detection, there is an effect that the cost can be greatly reduced as compared with using a separate distance measurement device.

  Regarding the relative relationship with the projected image, in the method of the present invention, since the distance is measured using the projected image, the position of the projected image itself can be accurately grasped, and on the screen. Since it is detected that the projected image is in focus, the distance from the projection lens to the image projected on the screen can be detected regardless of the setting state of the lens and the like. The state of the lens and the like means a difference between a wide side and a tele side in the case of a zoom lens. Therefore, there is an effect that the function can be realized more accurately and at lower cost than the method shown in the related art.

  As described above, according to the present invention, the three-dimensional inclination of the screen can be detected and corrected by projecting a test pattern using fewer components and the original function of the projector than the method shown in the related art. Therefore, it is more effective than the method shown in the related art.

  In addition, the projector device of the present invention displays a pattern on a screen by providing a means for displaying a pattern on a screen, detecting the position thereof, and calculating a position of the entire projection display screen of the projector from the position. By detecting the position and calculating the position of the entire projection display screen from the position, the position of the entire projection display screen can be accurately detected even when the image sensor is located farther from the projection lens. There is an effect that it can be performed.

  Further, in the projector device according to the present invention, by providing a means for correcting the optical distortion of the image sensor, the position of the entire projection display screen is accurately calculated from the position of the pattern on the screen even if there is optical distortion of the image sensor. And the relative position between the screen position and the entire position of the projection display screen can be accurately obtained.

  Furthermore, even when it is difficult to directly determine the optical distortion, the position of the projection display screen on which the image distortion correction was once performed is detected, and the image distortion correction is updated by comparing with the screen position to perform the image distortion correction. Providing means for controlling the position of the projection display screen so as to match the screen position has the effect that the relative position between the screen position and the entire position of the projection display screen can be accurately obtained.

  In addition, the center image used in the automatic correction of the present invention is used as it is, and the four corners are indicated by pointers, and the image correction is performed manually. There is an effect that adjustment can be performed as a final means in a series of operations on a screen, a wall, and the like that can only be detected by the camera.

  In addition, by displaying the center part image and the outer part image, including the center part image, and installing the screen inside the outer part image, the limit value of the signal processing circuit can be indicated implicitly, thereby correcting Has the effect of eliminating the situation in which it is impossible.

(First Embodiment of the Invention)
FIG. 1 shows a first embodiment of the present invention.

  Here, it is assumed that a projected image can be projected to a screen 4 via a light source (lamp) 1, a display device (liquid crystal panel) 2, and a projection lens 3. The image sensor 5 is located adjacent to the projection lens 3 and negligible compared to the distance to the screen 4. Typically, a raster scan type camera can be used as the image sensor 5 so as to capture the projected and displayed image and the shape of the screen 4.

  When a raster scan type camera is used as the image sensor 5, the image capturing result from the camera is captured by the image capturing unit 6 so as to be recognized as one picture. The image captured by the image sensor 5 has a range larger than the entire screen to be projected and displayed. First, the entire screen to be projected and displayed is captured by the image sensor 5 in advance, and the position of the entire screen to be projected and displayed on the image sensor captured image 21 is stored (FIG. 2).

  Next, the projector is installed so as to cover the entire screen surface of the installed screen 4, and the position of the screen 4 is detected from the image sensor captured image 21. The normal screen 4 has a surface on which a projected image is displayed is white or has a surface color reflecting light, and a portion (frame) outside the surface is a surface on which a projected image represented by black is displayed. It has a different color. The screen color and the frame can be detected by a method of recognizing a boundary point having different brightness and color from an image pickup result by the image sensor 5 and calculating a boundary line. The boundary line can be calculated by drawing an asymptotic line at each of the vertical and horizontal dividing positions of the screen 4. From the vertical and horizontal separation positions, it is also possible to detect the four corners of the screen that are the intersections.

  The detected screen position is combined with the above-described detection result of the entire projection display screen, and their relative positions can be determined. By knowing the relative position, the display position of the image on the display device 2 can be known, and the final target image shape for distortion correction can be known.

  The means for correcting distortion is described in the specification of Japanese Patent Application No. 2002-018407 or the like. If the distortion correction is performed using the distortion correction means and the distortion is corrected so as to match the detected screen position, the projector image can be projected in a form that exactly fits the target screen surface.

  Next, the operation of the first exemplary embodiment of the present invention will be described.

  The procedure of the automatic adjustment in the block diagram of FIG. 1 will be described below.

  First, at the stage of manufacturing or calibrating the projector device, a specific display such as all white or a cross hatch (lattice pattern) is performed on the display device 2 to detect the image position of the entire projection display screen on the image sensor.

  FIG. 2 shows a diagram showing this state.

  The position of the image sensor 5 is arranged inside the entire image 21 captured by the image sensor so that the entire image 22 of the projector display screen can be captured. The entire image 22 of the projector display screen is captured by the image sensor 5, and the position of the entire image 22 of the projector display screen in imaging by the image sensor 5 is detected.

  When the entire image 22 of the projector display screen is captured by the image sensor 5, the image is usually captured as a trapezoidal or slightly curved image due to the mounting accuracy of the image sensor 5, lens distortion, and the like.

  If an all white image is displayed, the four corners of the display image can be easily detected from the image of the entire image 22 of the projector projection display screen. If a cross hatch signal or the like is displayed, the projector projection display screen can be displayed. The specific position of the whole image 22 can be roughly determined from the line position of the cross hatch signal, and it becomes possible to know in detail where the whole image 22 of the projector projection display screen is taken in the image sensor 5.

  Similarly, by performing the display indicating the position on the entire image 22 of the projector projection display screen, it is possible to define the relationship between the position of the entire image 22 of the projector projection display screen and the position of the image sensor image 21.

  In the calibration, in the block diagram of FIG. 1, the all white signal or the cross hatch signal or the like is input from the video input unit 10, the image distortion correction circuit 11 is set to have no distortion, and the display device 2 is passed through the display device driving circuit 12. Or a test pattern generating circuit is provided in the display device driving circuit 12 to generate the above-mentioned signal to perform the projector display.

  At the time of calibration, it is convenient to perform the calibration if the screen 4 on which the image is projected is made a large object so that the entire image sensor captured image 21 fits within the screen. The projected display image is captured by the image sensor 5 and captured by the image capturing unit 6 as image data.

  The captured image at that time is shown in the example of the image sensor captured image in FIG. As described above, the entire projector projection display screen image 22 is rectangular when projected on the screen 4, but has some distortion when captured by the image sensor 5.

  The position of the image captured by the image capturing unit 6 is detected by the projection display position detecting unit 7. The position detection is performed on the image sensor captured image 21 between the horizontal and vertical x and y positions, and the horizontal and vertical display positions xp and yp in the entire projector projection display screen image 22. This is done in a way that represents the relationship one-on-one. For simplicity, it is also possible to express the above positional relationship with only some representative points. For example, it is the position of the four corners of the whole image 22 of the projector projection display screen, or the representative position of several points of the whole image 22 of the projector projection display screen.

  With the above operation, the calibration work is completed. As described above, the calibration operation is performed at the time of production at a factory or as an initial state of use.

  Next, the actual screen 4 is set, and the operation for detecting the position of the screen 4 is started. From the viewpoint of displaying an image on the entire screen, the entire projector projection display screen image 22 is installed so as to cover the entire screen 4. An example of an image obtained by capturing the screen 4 installed by the image sensor 5 is the screen position image 24 in FIG.

  As described above, the screen position is detected by utilizing the fact that the brightness and color of the frame portion are different from the original image display position which is the reflection surface. An image captured as shown in FIG. 3 by the image sensor 5 is captured by the image capturing unit 6 as data.

  The screen position is detected by the screen position detector 8 in the captured data.

  FIG. 4 shows a first configuration of the screen position detecting section 8. The brightness data 14 of the captured image is input to the binarization unit 15. The binarization unit 15 determines a binarization threshold from the histogram of the entire image. For example, a threshold is determined by a discriminant analysis technique (see Non-Patent Document 1). In this method, the brightness of each pixel in an image is checked, and the pixels are classified into two regions, a bright portion and a dark portion. The screen 4 is usually white and brighter than other parts of the screen, and thus is classified as a bright part. As a result, the screen portion in the image is cut out as shown in FIG. The binary image data output from the binarizing unit 15 is input to the straight line detecting unit 16. The straight line detecting means 16 traces the boundary between the bright part and the dark part, obtains the boundary, and divides the boundary into straight parts. FIG. 5 shows a state where four straight lines L1, L2, L3, and L4 are detected. Further, with respect to the detected straight line, the intersection detecting means 17 detects C1 as the intersection of L1 and L4, C2 as the intersection of L1 and L2, C3 as the intersection of L2 and L3, and C4 as the intersection of L3 and L4. As described above, the positions of the four corners of the screen 4 are determined.

  FIG. 6 shows a second configuration of the screen position detection unit 18. The brightness data 14 of the captured image is input to the edge detection unit 19. In the edge detecting means 19, each pixel is compared with an adjacent pixel value, and when the difference between the pixel values is larger than a preset threshold value, it is determined that the pixel has an edge. Then, an edge image as shown in FIG. 7 is obtained. Depending on the setting of the threshold value, an edge having a certain thickness is detected. In this case, a known thinning method is applied to output an edge image having a width of about one pixel. The straight line fitting means 20 performs straight line fitting on the obtained edge portion. Actually, a straight line equation is applied to the edge portion to determine straight lines L1 to L4. As in the first configuration, the intersection detecting means 17 obtains intersections of adjacent ones with the obtained straight line, and obtains the positions of the four corners of the screen 4.

  The detected position is located in the entire image 22 of the projector projection display screen, and the screen distortion detector 9 determines the relative positional relationship between the screen position and the display range of the display device 2. The image distortion correction circuit 11 displays an image in the form of a video to be displayed on the display device 2 determined by the screen distortion detection unit 9.

  As a result, the video signal input from the video input unit 10 passes through the image distortion correction circuit 11, is transformed into a shape conforming to the screen shape, and is displayed on the display device 2 via the display device drive circuit 12. The image is projected and displayed on the screen 4.

(Second embodiment of the invention)
As a second embodiment of the present invention, it is conceivable that the screen position image 24 does not fall within the range of the entire projector projection display screen image 22 after performing the screen position detection (FIG. 8).

  At this time, a satisfactory image cannot be provided to the user by the conventional treatment. As shown in FIG. 8, as a countermeasure, an image projected on the screen 4 is detected by detecting the screen position, and then performing similar scaling and moving the position within the screen. Calculating the size and position of an image that satisfies that it is within the range of the entire image 22 of the projector projection display screen while maintaining the rectangle, and displaying the image at the position on the display device 2 corresponding to the position. Accordingly, an image that can practically satisfy the user can be provided.

  This can be achieved by incorporating a process that satisfies the above conditions into the screen distortion detection unit 9.

(Third Embodiment of the Invention)
Regarding the mounting of the image sensor, the method according to the first embodiment in which the image sensor is located near the projection lens 3 and, as shown in FIG. 9, the image passed through the projection lens 3 is guided to the image sensor 5 by the half mirror 13. There is a method according to the third embodiment in which an image is picked up by the third embodiment. The half mirror 13 is not affected by the half mirror 13 during normal use as long as it is movable so as to be inserted between the display device 2 and the projection lens 3 only when the image sensor 5 captures an image.

(Fourth Embodiment of the Invention)
FIG. 10 shows a fourth embodiment of the present invention.

  When the screen is in the state of a so-called wall, the frame of the screen cannot be captured by the method of the first embodiment of the invention. At this time, the following method can be used.

  Here, it is assumed that a projected image can be projected to a screen 4 via a light source (lamp) 1, a display device (liquid crystal panel) 2, and a projection lens 3. The image sensor 5 is located adjacent to the projection lens 3 and negligible compared to the distance to the screen 4. Typically, a raster scan type camera can be used as the image sensor 5 so as to capture the projected and displayed image and the shape of the screen 4.

  When a raster scan type camera is used as the image sensor 5, the image capturing result from the camera is captured by the image capturing unit 6 so as to be recognized as one picture. The image captured by the image sensor 5 has a range in which the entire screen to be projected and displayed can be captured.

  First, means for measuring the distance between the projection lens and the screen on which the image is projected and projected will be described.

  In a projector having a built-in image sensor 5, the relationship between the distance from the projector to the screen 4 and the focus position of the lens corresponding to the position where the projected image is in focus (hereinafter referred to as a focus profile) is determined in advance by a factory that manufactures the projector. Is stored.

  By this operation, in a scene used by the user, the focus position of the lens in focus is detected, and the distance from the projector to the focused screen 4 can be known by comparing the focus position with the focus profile. it can.

  Next, the in-focus position at each of the four corners on the display screen when projected on the actual screen 4 is detected by changing the focus position of the lens and illuminating the focus profile. It is possible to know the respective distances to the four corners of the projected display screen.

  Hereinafter, a method of obtaining the distances from the projector to the four corners of the display screen will be described in detail.

  First, a representative example of a test pattern for measuring the focus at the four corners of the screen is a pattern as shown in FIG. The outer periphery indicates a display area of the display device 2. A cross-shaped test pattern is projected so as to be located at the four corners of the screen, and a focus point at the position of the cross-shaped test pattern is detected. The relationship between the position of the focus point and the distance (focus profile) is measured in advance as shown in FIG. This measurement is usually performed when the projector is manufactured, and is stored in the projector body. By detecting a focus position at which focus is achieved at four corners of the screen by the focus profile of FIG. 12, it is possible to detect the distance from the screen 4 at each point. If the focus profiles are slightly shifted at the four corners of the screen, the focus profiles may be created for each of the four points. By the above measurement, the distance between the projection lens 3 and the test pattern positions at the four corners on the screen 4 from the projection lens 3 and the projection lens 3 can be more accurately grasped than in the prior art.

  If the distance from the projector to the four corners of the display screen can be known, the positional relationship between the projector and the screen 4 can be understood.

  Assuming that the screen 4 is a plane, the plane constituting the projected screen can be represented by an inclination angle of the xy axis with respect to the projector. If the screen 4 has a rectangular shape with a frame, the rotation angle is further added to the relationship between the projected screen and the screen plane. However, when considering only how to distort the projected screen purely, there is no need to consider the relationship between the square screen frame and the projected screen, only the positional relationship between the plane on which the projected screen is displayed and the projector. .

  Also, the three-dimensional inclination of the screen 4 is calculated from the distance from the projector to the four corners of the display screen, and if the screen 4 is assumed to be flat, the display screen shape to be corrected can be known.

  In the projected and displayed screen, the projected magnification in the screen changes depending on the inclination angle of the flat screen. FIGS. 13 and 15 show the case where the projector and the flat screen face each other. FIGS. 14 and 16 show the case where the flat screen is inclined with respect to the projector.

  The change in the magnification is proportional to the ratio of the projection distance. For example, in the case where the projection display is performed at the projection distance of 1 m and the case where the projection display is performed at the projection distance of 2 m, the enlargement ratio is twice.

  The magnification of the screen can be expressed as a ratio from the center of the screen. That is, by measuring the distance and calculating the ratio of each of the positions 1, 2, 3, and 4 representing the four corners of the screen, the difference in the enlargement ratio can be calculated. And a coefficient for operating the distortion correction means described in the specification of Japanese Patent Application No. 2002-018407.

  In the block diagram of FIG. 10, the procedure of the automatic adjustment is described below.

  In FIG. 10, a specific pattern appears at the corner of the projection screen field, and the focus adjustment of the optical lens is operated to detect the best focus point of each specific pattern by the focus detection unit 26.

  The lens focus position at that time is detected by the lens focus position detection unit 27, so that the distance to the best focus point is calculated.

  The distance detection unit correction coefficient calculation unit 28 generates a correction coefficient corresponding to each distance.

  The correction coefficient is obtained by calculating the inclination angle φ of the screen 4 shown in FIG. 14 for each of the xy axes from the distance from the projector to the four corners, and calculating the change in the enlargement ratio. , The image distortion can be corrected according to the detected screen tilt.

(Fifth Embodiment of the Invention)
When the screen is limited to a flat surface, distance detection can be performed at three points instead of four points. Assuming that the screen is flat, the projected state of the image can be represented by the rotation about the a-axis and the b-axis shown in FIG. In order to express the rotation on the a-axis and the b-axis, if two points indicating the inclination / position of the b-axis with respect to the a-axis and one point indicating the rotation angle with respect to the b-axis are determined, the inclination can be obtained. .

(Sixth Embodiment of the Invention)
Even when the screen is a curved screen, it is possible to calculate the image distortion correction coefficient by increasing the points to be detected in a mesh shape and performing interpolation between detection points by linear interpolation or higher-order curve interpolation, Automatic image distortion correction can be realized.

(Seventh Embodiment of the Invention)
The first to sixth embodiments of the present invention are directed to a method for automatically correcting trapezoidal distortion caused by tilt projection of an image by using an image sensor built in the projector. This method detects the screen position relative to the entire display screen position and corrects the image distortion so that the projected image matches the screen.However, this method requires that the entire projection display screen on the image sensor be detected in advance by calibration. In this case, the entire position of the projection display screen is a fixed value.

  At this time, as a method of incorporating the image sensor, there are a method of guiding an image through a projection lens by a half mirror or the like to take an image, and a method of positioning the image in the vicinity of the projection lens in a projection direction. If the position of the projection lens does not match the imaging position of the image sensor as in the case, the entire position of the projection display screen imaged on the image sensor by the tilt projection changes, and the degree of this change is the degree of the tilt projection. In this method, the entire position of the projection display screen is detected in advance by calibration because the size of the projection display screen does not match the actual position of the entire projection display screen on the image sensor during projection. When detecting the position and performing image distortion correction so that the projected image fits on the screen Will occur a difference, screen and projected projector image can not match.

  For this reason, it is sufficient to detect the position of the entire projection display screen every time the screen position is detected. However, in the automatic image distortion correction using the screen position detection, the entire screen display image of the projector is detected for the screen position detection. Since the projection is performed so as to cover the screen, the boundary of the entire projection display screen is located outside the screen, and it is expected that there are various objects outside the screen. It is difficult to detect.

  In the seventh embodiment of the present invention, the position of the entire projection display screen can be detected by displaying the pattern on the screen and detecting the position, and calculating the position of the entire projection display screen from the position. You can do it.

  This makes it possible to accurately detect the position of the entire projection display screen even if the image sensor is located farther than the projection lens.

  Referring to FIG. 18, there is shown a projector device having an automatic image distortion correcting function according to a seventh embodiment of the present invention.

  1 is a light source (lamp) of the projector, 2 is a display device (liquid crystal panel), 3 is a projection lens of the projector, 4 is a screen for projecting an image, and 5 is a projection direction for capturing the screen and the projected image. 6 is an image capturing unit that captures an image captured by the image sensor, 33 is an image sensor optical distortion correction circuit for correcting optical distortion of the image sensor, and 7 is an image captured by the image sensor. A projection display position detection unit that detects a display position of a projection image in an image, 8 is a screen position detection unit that detects a screen position in an image captured by an image sensor, and 41 is a position of the entire projection display screen from the result of 7 A projection display screen overall position calculation unit 9 for calculating the screen distortion from the relative position of 41 and 8; And 10, an image input unit for inputting an image projected by the projector, 11 an image distortion correction circuit for correcting distortion based on the result of 9, and 12 a display device drive for displaying the image from 11 on the 2 display device A circuit 23 is a display pattern generation unit that generates a pattern for detecting the projection display position at 7.

    The operation of the seventh embodiment of the present invention will be described with reference to FIG.

  The projector is installed so that the entire projection display screen of the projector covers the screen 4, an image is captured by the image sensor 5, the captured image is captured by the image capturing unit 6, and the image sensor 5 corrects the image by the image sensor optical distortion correction circuit 33. To correct optical distortion. The captured image is like the screen position image 24 in FIG. 19, and the screen position detection unit 8 detects the position of the screen 4 by detecting the boundary of the screen position image 24. Here, the correction of the optical distortion in the image sensor 5 in the image sensor optical distortion correction circuit 33 may be performed by calculation, or may be performed using optical distortion correction data prepared in advance. .

  Next, the position of the entire projection display screen is detected by displaying two types of all-white patterns inside the screen 4 as follows, detecting the position, and calculating from the result.

  First, the display pattern generation unit 23 displays an all-white pattern on the screen 4 having a length and width of 75% of the entire projector projection display screen. The pattern is imaged by the image sensor 5 and the image capture unit 6 is displayed. Then, the captured image is captured, and the optical distortion in the image sensor 5 is corrected by the image sensor optical distortion correction circuit 33. Then, the position is detected by the projection display position detection unit 7, and the position is detected by the projection display screen entire position calculation unit 41. send. Next, the display pattern generation unit 23 displays on the screen 4 an all-white pattern in which the length and width are 50% of the entire projector projection display screen. At 6, the captured image is fetched and the position is detected by the projection display position detection unit 7 and sent to the entire projection display screen position calculation unit 41.

  At this time, the captured 75% all-white pattern and the 50% all-white pattern are like the 75% all-white display image 34 and the 50% all-white display image 35 in FIG. The positions of the 75% all-white display image 34 and the 50% all-white display image 35 are detected by detecting the boundaries between the% all-white display image 34 and the 50% all-white display image 35, respectively, and the entire projection display screen position calculation unit In step 41, the position of the entire projector projection display screen image 22 is calculated from the relative positions of the 75% all white display image 34 and the 50% all white display image 35.

  Next, the display device 2 is determined based on the relative positional relationship between the screen position detected by the screen position detector 8 and the position of the entire projector projected display screen image 22 detected by the projected display screen overall position calculator 41. The position of the screen 4 above is determined. Thereby, the final target image shape of the distortion correction can be known, and the image distortion correction circuit 11 performs distortion correction on the video signal from the video input unit 10 so as to have the final target image shape of the distortion correction detected by the screen distortion detection unit 9 and projects the image signal. I do.

  The means for distortion correction is described in the specification of Japanese Patent Application No. 2002-018407, etc., and performs distortion correction using the above-described distortion correction means, and corrects the distortion to match the detected screen position. Is performed, the projector image can be projected in a form that matches the target screen surface.

  The two patterns need not be 75% and 50%, and may not be all white.

  In the above-described example, two full white patterns of 75% and 50% are displayed and their positions are detected to calculate the position of the entire image 22 of the projector projection display screen. For example, as shown in FIG. It is also possible to display the pattern of the white display image 34 and the pattern of the center display image 36 indicating the center, detect the position, and calculate the position of the entire projector projection display screen image 22 from the relative position.

(Eighth Embodiment of the Invention)
FIG. 22 shows a projector device having an automatic image distortion correcting function according to an eighth embodiment of the present invention.

  In the present embodiment, the optical distortion correction of the image sensor 5 is not directly performed as compared with FIG. 18, but the image distortion is once corrected by the method of the above-described seventh embodiment of the present invention. The projection display position after correction and the screen position are compared, and correction is performed by feedback control so that they match.

  In the above-described seventh embodiment, when the relative positional relationship is obtained from the screen position detected by the screen position detection unit 8 and the position of the entire projector projection display screen image 22 calculated by the entire projection display screen position calculation unit 41, The position of the screen 4 on the display device 2 is known so that the final target image shape of the distortion correction can be known, and the image distortion correction circuit 11 performs distortion correction so as to match the screen position and adjusts to the target screen surface. When the image sensor 5 has optical distortion and cannot be corrected by the image sensor optical distortion correction circuit 33, the image projected on the screen 4 and the image distortion corrected image are matched with the screen 4. do not do. That is, when optical distortion is complicated and calculation is difficult, or it is difficult to prepare optical distortion correction data in advance.For example, it is necessary to measure optical distortion characteristics for each projector device to be produced and create data. If it is time-consuming and impractical, the optical distortion correction as in the seventh embodiment cannot be performed.

  For this reason, in the present embodiment, a projection display screen position-screen position comparison unit 29 and an image distortion correction data unit 40 are added instead of the image sensor optical distortion correction circuit 33 of FIG. Are input not to the display device driving circuit 12 but to the image distortion correction circuit 11 so that the generated pattern output is subjected to image distortion correction.

  First, the image distortion correction circuit 11 does not perform image distortion correction, that is, the image signal from the image input unit 10 is output to the display device drive circuit 12 as it is, and the same method as in the above-described seventh embodiment is used. , The position of the screen 4 is detected by the screen position detection unit 8, the position of the entire projector projection display screen is calculated by the whole projection display screen position calculation unit 41, and the screen distortion detection unit 9 calculates the display device from the relative positional relationship between them. The final target image shape for distortion correction is detected by obtaining the position of the screen on 2.

  Next, the detected shape is reduced as shown in FIG. 23 and stored in the image distortion correction data section 40. The image distortion correction circuit 11 performs image distortion correction based on the data stored in the image distortion correction data section 40. So that the output signal of the image distortion correction circuit 11 that has been subjected to the image distortion correction is projected. At this time, since the output of the screen distortion detection unit 9 is reduced and stored in the image distortion correction data unit 40, the projected image is displayed inside the screen as shown in FIG. Here, the reduction is performed in a range that is not displayed outside the screen 4 in consideration of an error 32 in the calculation of the entire position of the projector display screen in the entire projection display screen position calculation unit 41 due to the optical distortion of the image sensor 5.

  The display pattern generator 23 displays a 100% all white pattern, that is, a pattern of the full screen display image size of the projector. The detection unit 7 detects the projection display position. Here, since the output of the screen distortion detection unit 9 is reduced as described above, this 100% all white pattern is displayed inside the screen 4 as shown in the reduced display range 31 in FIG.

  When the image is not reduced, that is, when the image distortion correction is performed on the entire range 38 of the projector projection display screen detected in FIG. 23, the display range 30 is not reduced. Error 32 due to distortion.

  Next, the position of the projection display screen detected by the projection display position detection unit 7 and the screen position detected by the screen position detection unit 8 are compared by the projection display screen position-screen position comparison unit 29, and the projection display screen position is determined. The image distortion correction data of the image distortion correction data unit 40 is updated so that the image changes in a direction corresponding to the screen position. Then, the imaging of the displayed 100% all-white pattern, the detection of the projected display screen position, the comparison with the screen position, and the update of the image distortion data are repeated, and finally the projected display detected by the projected display position detecting unit 7. Control is performed so that the screen position matches the screen position detected by the screen position detection unit 8. At this time, since the position of the pattern projected outside the screen cannot be correctly detected, the image distortion correction data is always updated from the inside of the screen so as to match the screen.

(Ninth Embodiment of the Invention)
FIG. 25 shows a ninth embodiment. In addition to the block diagram of the fourth embodiment (FIG. 10), a pointer control / display unit 42 on the screen is added.

  The actual image distortion correction operation has a limit depending on the circuit configuration. As shown in FIG. 26, the center image 43 and the outer image 44 are displayed, and the screen 4 includes the center image 43 and the outer image is displayed. The video 44 is installed so as not to protrude. This action implicitly instructs the user on the operating range of the image distortion correction, and when performing the automatic correction, the correction operation can be performed within the circuit limit. This makes it impossible to execute the correction by the correction.

  However, it is difficult to automatically detect the screen 4 when a pattern or the like is displayed on the screen 4 or the outer frame of the screen 4 or in a case of a transmission type screen.

  In such a case, conventionally, a completely different manual correction mode has been provided (for example, disclosed in Patent Document 1).

  In the embodiment of the present invention, as shown in FIG. 27, the center image 43 used at the time of the above automatic correction is used as it is, and the four corners are indicated by pointers, thereby performing the image correction manually. An uninterrupted operation flow can be constructed, and the user can perform the image distortion correction operation in a minimum time.

  The automatic adjustment method is the same as in the fourth embodiment, and the subsequent manual adjustment operation will be described.

  After the automatic adjustment has failed, points that can be pointed at the four corners are explicitly displayed on the center image 43 to indicate that the point can be pointed. Thereafter, the position on the display screen and the four corners of the screen are associated with each other by matching the four corners of the center image 43 with the four corners of the screen 4 by a pointer provided in the apparatus. The correction can be performed by performing the correction in the image distortion correction circuit 11 to be performed.

It is a figure showing a 1st embodiment of the present invention. FIG. 3 is a diagram illustrating an example of an image captured by an image sensor. It is a figure showing the example of a screen position image. FIG. 3 is a diagram illustrating a first configuration of a screen position detection unit. It is a figure showing signs that four straight lines of L1, L2, L3, and L4 were detected. FIG. 9 is a diagram illustrating a second configuration of the screen position detection unit. It is a figure showing signs that an edge image was obtained. FIG. 11 is a diagram illustrating a case where the screen position image does not fall within the range of the projector full-screen display image after performing the screen position detection. FIG. 11 is a diagram illustrating a third embodiment in which an image that has passed through a projection lens is guided by a half mirror to an image sensor to capture an image. It is a figure showing a 4th embodiment of the present invention. FIG. 4 is a diagram showing a test pattern for measuring focus at four corners of a screen. FIG. 4 is a diagram illustrating a relationship (focus profile) between a distance from a projector to a screen and a focus position of a lens corresponding to a position where a projected image is in focus. FIG. 3 is a diagram illustrating a case where a projector and a flat screen face each other. It is a figure showing the case where a flat screen is inclined to a projector. FIG. 3 is a diagram illustrating a case where a projector and a flat screen face each other. It is a figure showing the case where a flat screen is inclined to a projector. FIG. 7 is a diagram showing that a projected state of an image can be represented by rotation on the a-axis and the b-axis, assuming that the screen is a plane. It is a figure showing a 7th embodiment of the present invention. FIG. 5 is a diagram illustrating an example of an image captured by an image sensor (a whole image of a projector projection display screen and a screen position image). It is a figure which shows the image pick-up image example (75% all white display image and 50% all white display image) of an image sensor. It is a figure which shows the example of a captured image of an image sensor (75% all white display image and center display image). It is a figure showing an 8th embodiment of the present invention. FIG. 3 is a diagram illustrating an image on a display device. It is a figure showing a projection picture on a screen. It is a figure showing a 9th embodiment of the present invention. It is a figure which shows a center part image and an outer peripheral part image, and shows that a screen is installed so that a central part image is included and an outer peripheral part image does not protrude. FIG. 14 is a diagram showing that image correction is manually performed by using the center image used at the time of automatic correction as it is and pointing the four corners with pointers.

Explanation of reference numerals

1 light source (lamp)
2 Display device (liquid crystal panel)
Reference Signs List 3 Projection lens 4 Screen 5 Image sensor 6 Image capture unit 7 Projection display position detection unit 8, 18 Screen position detection unit 9 Screen distortion detection unit 10 Image input unit 11 Image distortion correction circuit 12 Display device drive circuit 13 Half mirror 14 Image Brightness data 15 Binarization means 16 Straight line detection means 17 Intersection detection means 19 Edge detection means 20 Straight line fitting means 21 Image sensor captured image 22 Projector projection display screen whole image 23 Display pattern generation unit 24 Screen position image 25 Position / size Corrected display image 26 Focus detector 27 Lens focus position detector 28 Distance detector correction coefficient calculator 29 Projection display screen position-screen position comparator 30 Non-reduced display range 31 Reduced display range 32 Error due to optical distortion 3 3 Image Sensor Optical Distortion Correction Circuit 34 75% All White Display Image 35 50% All White Display Image 36 Center Display Image 37 Image on Display Device 38 Detected Projector Projection Display Screen Entire Range 39 38 Display Range Reduced 38 Image 40 Distortion correction data part 41 Projection display screen whole position calculation part 42 Pointer control / display part on screen 43 Central part image 44 Outer part image

Claims (20)

A projector device that enlarges and projects an image displayed on a display device that performs dot matrix display,
An image distortion correction circuit that realizes correction of image distortion by deforming the display on the display device, and an image sensor that can capture an image projected and displayed and a screen installed near the projection screen. Prepare,
A function of calculating the position of the screen from the position of the display screen of the projector device from the image captured by the image sensor, and the shape of the screen installed near the projection screen; A projector device that can display an image matched to the screen by the image distortion correction circuit based on the information of (1). 2. The projector device according to claim 1, wherein the image sensor is located near a projection lens that enlarges and projects the projected and displayed image. The projector device according to claim 1, wherein the image sensor can capture an image passing through a projection lens with the image sensor. 2. The projector device according to claim 1, wherein when the image projected and displayed and the shape of the screen are identified, the positions of the four corners are detected to identify the positions. . 2. The projector device according to claim 1, wherein when the image projected and displayed and the shape of the screen are identified, some representative points on the image are identified. 3. 2. The projector device according to claim 1, wherein an image for a test is projected and displayed when the image sensor identifies the image. 2. The projector device according to claim 1, wherein the display position and the size of the image on the display device can be changed by a similar shape of the detected screen shape. Projector device. 8. The projector device according to claim 7, wherein when a position of the display screen of the screen is different from a position of the display screen of the projector device, the display screen of the screen overlaps with the display screen of the projector device. A projector device that can display an image on a part. A projector device that enlarges and projects an image displayed on a display device that performs dot matrix display,
An image distortion correction circuit that realizes correction of image distortion by deforming the display on the display device, and an image sensor that can capture an image projected and displayed and a screen installed near the projection screen. Prepare,
By calculating distances between a plurality of points on the display screen of the projector device and the projector device from the image captured by the image sensor, the positional relationship between the projector device and the screen is detected, and the detected positional relationship is calculated. A projector device that can display an image in a desired shape on the screen by the image distortion correction circuit based on information. The projector device according to claim 9, wherein the image sensor is positioned near a projection lens that enlarges and projects the projected and displayed image. The projector device according to claim 9, wherein the image sensor can capture an image passing through a projection lens with the image sensor. The projector device according to claim 9, wherein a distance from the projector device to the screen is detected by detecting a state in which the image is in focus using the projected and displayed image. Projector device. The projector device according to claim 9, wherein when identifying the positional relationship between the projector device and the screen, some representative points on an image are identified. The projector device according to claim 9, wherein an image for a test is projected and displayed when detecting a positional relationship between the projector device and the screen. 14. The projector device according to claim 13, wherein, as means for identifying some representative points on the image, a specific representative point blinks and the blinking state is identified by the image sensor. Projector device configured to be recognized as a specific position. When the shape and position of the screen cannot be calculated by the method of the projector device according to claim 1, an automatic image distortion correction function by the method of the projector device according to claim 9 is automatically executed, and the image distortion is reduced. Projector device with a function to correct the image. 2. The projector device according to claim 1, wherein the position of the entire projection display screen is detected by displaying a pattern on the screen and detecting the position, and calculating the position of the entire projection display screen from the position. A projector device comprising: 18. The projector according to claim 17, further comprising: a unit configured to correct optical distortion of the image sensor. 18. The projector device according to claim 17, wherein a means for comparing the position of the projection display screen after distortion correction and the screen position to correct an error due to optical distortion of the image sensor, and feeding back the result of the comparison. A projector device comprising means for updating distortion correction so that the position of the projected display screen after distortion correction matches the screen position. 13. The projector device according to claim 12, wherein after the automatic adjustment has failed, displaying a central portion image and an outer peripheral portion image, including the central portion image, and the inner side than the outer peripheral portion image. By installing the screen, instruct the user of the limit of the image distortion correction range, eliminate the uncorrectable state, by using a pointer to match the four corners of the center image to the four corners of the screen, A projector device that associates a position on a display screen with four corners of the screen and performs correction by the image distortion correction circuit.

Images