JP3996610B2 - Projector apparatus and image distortion correction method thereof - Google Patents

Description

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

  In the projector apparatus, image distortion correction that occurs when the screen does not face the projector apparatus is described in the specification of Japanese Patent Application No. 2002-018407.

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

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

  Among them, the correction method for the screen is still a correction that relies on manual operation as usual. If only the trapezoidal distortion correction only in the vertical direction or the horizontal direction is possible, manual correction can be easily performed, but the oblique direction. As for the distortion correction, the correction operation is very difficult.

  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 the projection optical axis inclined with respect to a screen (see, for example, Patent Document 1).

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

  In addition, there is a projector device that can detect the distance from the projection lens to the screen, calculate the tilt angle from the detection result, and automatically provide distortion correction (see, for example, Patent Documents 4, 5, and 6). ).

Further, as a method for binarizing the brightness data of a captured image, there is a method for determining a threshold for binarization from a histogram of the entire image, for example, a method for determining a threshold by a discriminant analysis technique (for example, Non-patent document 1).
JP 2002-44571 A JP 2001-83949 A Japanese Patent Application Laid-Open No. 2001-169211 JP-A-4-355740 JP 2000-81593 A 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 of providing a distance measuring device independently of the original function of the projector and using a projected image. Further, in order to measure the 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. As for the projected image, the position and the size of the screen largely change depending on the state of the projection lens. Therefore, by simply measuring the positional relationship between the projector and the screen, correction suitable for the image actually displayed is made. It is unknown.

  In addition, regarding the position being measured, an accurate position cannot be indicated due to the installation error of the distance measuring device or the variation in the mechanical positional relationship between the projection lens and the display device.

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

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 projector device of the present invention is
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
An image distortion correction circuit that deforms an image signal supplied to the display device,
The image sensor images the screen;
The image distortion correction circuit is configured so that the shape of the projection image generated from the supply image matches the area of the screen based on the positional relationship between the entire image on the projection display screen and the captured screen. Transforming the supply image ,
The projection lens projects a first projection display position detection pattern displayed on the display device;
The image sensor images the projected first projection display position detection pattern,
The projection lens projects a second projection display position detection pattern displayed on the display device;
The image sensor images the projected second projection display position detection pattern,
The entire projection display screen image is calculated based on the captured first and second projection display position detection patterns,
The first projection display position detection pattern includes a first white region;
The second projection display position detection pattern includes a second white region;
The first white region is a region obtained by reducing the entire display region to 3/4 each of the vertical and horizontal directions on the display device, and is located at the center of the entire display region,
The second white area is an area obtained by reducing the entire display area to ½ each in the vertical and horizontal directions on the display device, and is located in the center of the entire display area .
A projector apparatus according to another embodiment of the present invention is provided.
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
An image distortion correction circuit that deforms an image signal supplied to the display device,
The image sensor images the screen;
The image distortion correction circuit is configured so that the shape of the projection image generated from the supply image matches the area of the screen based on the positional relationship between the entire image on the projection display screen and the captured screen. Transforming the supply image,
The projection lens projects a first projection display position detection pattern displayed on the display device;
The image sensor images the projected first projection display position detection pattern,
The projection lens projects a second projection display position detection pattern displayed on the display device;
The image sensor images the projected second projection display position detection pattern,
The entire projection display screen image is calculated based on the captured first and second projection display position detection patterns,
The first projection display position detection pattern includes a first white region;
The second projection display position detection pattern indicates the center of the entire display area of the display device .
In this case, the first white area may be an area obtained by reducing the entire display area to 3/4 each of the vertical and horizontal directions on the display device, and may be located at the center of the entire display area .

The projector device of the present invention is
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
A correction coefficient calculation unit for calculating a correction coefficient;
An image distortion correction circuit for deforming a supply image to the display device according to the correction coefficient,
The projection lens projects a test image displayed on the display device;
The image sensor captures the projected test image,
The correction coefficient calculation unit calculates the correction coefficient based on the captured test image .
In this case, a distance detector for obtaining a positional relationship between the screen and the projection lens is provided.
A plurality of test patterns are arranged near the four corners of the test image,
The distance detector obtains the positional relationship by calculating the distance between the projected test pattern and the projection lens,
The correction coefficient calculation unit may calculate the correction coefficient based on the positional relationship .
The test pattern may be a cross shape .
The test image may include four test patterns .
The test image may include only three test patterns .
The test image may include the test pattern in a mesh shape .
Further, a manual adjustment operation unit that manually controls the image distortion correction circuit may be provided .
The manual adjustment operation unit may be a pointer control / display unit that controls and displays a pointer .
The image sensor may capture an image through the projection lens.
A projector apparatus according to another embodiment of the present invention is provided.
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
An image distortion correction circuit that deforms an image signal supplied to the display device,
The image sensor images the screen;
The image distortion correction circuit deforms the supplied image based on a positional relationship between the entire image on the projection display screen and the captured screen.
In this case, the image distortion correction circuit may deform the supply image so that the shape of the projection image generated from the supply image matches the area of the screen.
Further, the image distortion correction circuit may deform the supplied image so that the shape of the projection image generated from the image signal matches the area obtained by reducing the screen.
The image sensor captures the projected image and the screen,
The image distortion correction circuit may further deform the supplied image so that the shape of the projection image generated from the image signal matches the area of the screen.
Further, the position of the entire image on the projection display screen may be obtained in advance by calibration during production in a factory.
The position of the entire projection display screen image may be obtained by calibration as an initial state to be used.
Further, the projection lens projects a projection display position detection pattern displayed on the display device,
The image sensor images the projected projection display position detection pattern,
The entire projection display screen image may be calculated based on the captured projection display position detection pattern.
The projection lens projects a first projection display position detection pattern displayed on the display device,
The image sensor images the projected first projection display position detection pattern,
The projection lens projects a second projection display position detection pattern displayed on the display device;
The image sensor images the projected second projection display position detection pattern,
The entire projection display screen image may be calculated based on the captured first and second projection display position detection patterns.
The first projection display position detection pattern includes a first white area,
The second projection display position detection pattern may include a second white area.
Further, the first white area is an area reduced to 3/4 of the entire display area on the display device, and is located at the center of the entire display area,
The second white area may be an area obtained by reducing the entire display area to 1/2 in the vertical and horizontal directions on the display device, and may be located at the center of the entire display area.
The first projection display position detection pattern includes a first white area,
The second projection display position detection pattern may indicate the center of the entire display area of the display device.
The first white area may be an area obtained by reducing the entire display area to 3/4 in the vertical and horizontal directions on the display device, and may be located at the center of the entire display area.
Further, when the captured screen is not included in the entire image of the projection display screen, the image distortion correction circuit is arranged so that a projection image generated from the supply image is included in the screen. Movement or similar enlargement or reduction may be performed.
Further, a manual adjustment operation unit that manually controls the image distortion correction circuit may be provided.
The manual adjustment operation unit may be a pointer control / display unit that controls and displays a pointer.
The image sensor may capture an image through the projection lens.
An image distortion correction method for a projector device according to the present invention includes:
Project the test image displayed on the display device through the projection lens,
The projected test image is captured by an image sensor disposed in the vicinity of the projection lens,
Calculating a correction coefficient based on the captured test image;
A supply image to the display device is deformed according to the correction coefficient.
An image distortion correction method for a projector device according to another aspect of the present invention includes:
Take an image of the screen with an image sensor located near the projection lens,
The supply image to the display device is deformed based on the positional relationship between the entire projected display screen image and the captured screen.
The present invention relates to a projector composed of a dot matrix that magnifies and projects a display device onto a screen, and detects the position of the screen relative to the projected image display range when the screen is projected in a state of not facing the projector. Then, image distortion correction is performed so that the projected image fits the screen.

  In addition, the present invention relates to a projector that is composed of a dot matrix and projects a display device on a screen by enlarging and projecting the display device. The distance to the corner of the corner is detected, and the tilt angle of the projected image is calculated from the difference between the distances, thereby detecting the distortion of the image and performing the inverse correction to correct the image distortion.

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

  However, correction can be performed by the same means as long as the distances from the projection lens to the four corners of the rectangle can be known without using a two-dimensional image sensor. An example of this means is also given.

  In order to detect the distance from the projection lens to the four corners on the display screen or a portion close to the four corners by the two-dimensional image sensor, a rotational position detection sensor is attached to the focus adjustment mechanism of the projection lens. The distance between the rotational position detection sensor and the in-focus 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 other hand, the image is displayed out of focus at the out-of-focus position. When this display image is captured by the two-dimensional image sensor, the contrast of the captured image is maximized at the focused position. By detecting the position where the contrast becomes maximum, it is possible to detect the position where the focus is achieved.

  Knowing the distance from the projection lens to the screen using the signal from the rotation position detection sensor mounted on the focus adjustment mechanism at the in-focus position and the distance data from the projection lens previously detected and stored be able to.

  In order to know the focus position, it is possible to effectively assist the focus adjustment operation by displaying in advance on the display device an image that allows easy focus detection.

  Up to four corners on the projected screen can be imaged by the two-dimensional image sensor. 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 determined. You can know at the same time.

  With the above operation, it is possible to know the distance from the projection lens to the four corners of the screen, and as a result, it is possible to detect the angle at which the projector and the screen are inclined with respect to each other and to calculate the distance. Image distortion correction is automatically realized by reversely correcting image distortion.

  The present invention has the following effects.

  In the distance measuring method of the present invention, as a distance measuring device, one image sensor, a projected image (using a function of projecting an image which is a basic function of the device), a point where the focus is achieved, and a focus in the projection lens It can be detected by using the position. As can be seen, the configuration as a distance measuring device is made using the original function of the projector device, and is different from the conventional technology that can be used separately. Additional functions as a distance measuring device include a focus position sensor (position sensor using a variable resistor) to be added to the lens, a test pattern generation circuit, and a single image sensor. In order to detect, it is necessary to measure at three or more locations, so that there is an effect that the cost can be greatly reduced as compared to using a distance measuring device separately.

  As for the relative relationship with the projected image, the method of the present invention measures the distance using the projected image, so that the position of the projected image itself can be accurately grasped and is displayed on the screen. In order to detect that the projected image is in focus, there is an effect that 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 means a difference between the wide side and the tele side in the case of a zoom lens. Therefore, there is an effect that the function can be realized more accurately and at a lower cost than the method shown in the prior art.

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

( First reference example )
FIG. 1 shows a first reference example .

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

  When the raster scan type camera is the image sensor 5, the image capturing result from the camera is captured so that the image capturing unit 6 can recognize it as one picture. The video that can be captured by the image sensor 5 is 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, a projector is installed so that the whole screen surface of the installed screen 4 may be covered, and the position of the screen 4 is detected from the image sensor captured image 21. The normal screen 4 has a white surface or a surface color that reflects light, and the outer surface (frame) is a surface that displays a projected image represented by black. It is a different color. The screen 4 can be detected by a method of recognizing boundary points of different brightness and color from the image pickup result of the image sensor 5 and calculating the boundary line. The boundary line can be calculated by drawing asymptotic lines for the vertical and horizontal separation positions of the screen 4. It is also possible to detect the four corners of the screen that are the intersections from the vertical and horizontal separation positions.

  The detected screen positions can be combined with the detection results of the entire projection display screen described above, 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.

  Means for distortion correction are described in the specification of Japanese Patent Application No. 2002-018407. If distortion correction is performed using the distortion correction means and distortion correction is performed so as to match the detected screen position, a projector image can be projected in a form that closely matches the target screen surface.

Next, the operation of the first reference example will be described.

  In the block diagram of FIG. 1, the procedure of automatic adjustment is shown below.

  First, in manufacturing or calibration of the projector device, specific display such as all white or 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 is a diagram showing the situation.

  The position of the image sensor 5 is arranged inside the entire image sensor captured image 21 so that the entire projector projection display screen entire image 22 can be captured. The image sensor 5 captures the entire projector projection display screen image 22 and detects the position of the entire projector projection display screen image 22 when the image sensor 5 captures the image.

  When the entire projector projection display screen image 22 is captured by the image sensor 5, the image is captured as a normal trapezoidal or slightly curved image depending on 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 projector projection display screen image 22, and if a cross hatch signal or the like is displayed, the projector projection display screen The specific position of the entire image 22 can be roughly determined from the line position of the cross hatch signal, and it is possible to know in detail in which position of the image sensor 5 the entire image projected on the projector projection screen 22 is captured.

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

  In the block diagram of FIG. 1, the calibration is performed by inputting the all white signal or the cross hatch signal from the video input unit 10 and setting the image distortion correction circuit 11 to be no distortion, through the display device driving circuit 12 and the display device 2. The display device driving circuit 12 is provided with a test pattern generation circuit, and the projector generates a display by generating the signal.

  At the time of calibration, it is convenient at the time of calibration if the screen 4 on which the image is projected is a large object so that the entire image captured by the image sensor 21 is within the screen. The projected display image is picked up by the image sensor 5 and taken into the apparatus as image data by the image take-in unit 6.

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

  The position of the image captured by the image capture unit 6 is detected by the projection display position detection unit 7. In the position detection, the horizontal and vertical positions x and y on the captured image 21 of the image sensor and the horizontal and vertical display positions xp and yp of the entire projector projection display screen image 22 are detected. The relationship is expressed in a one-to-one relationship. In a simple manner, the positional relationship can be expressed by only some representative points. For example, the positions of the four corners of the entire projector projection display screen image 22 or several representative positions of the entire projector projection display screen image 22 are shown.

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

  Next, the actual screen 4 is installed and the operation of detecting the position of the screen 4 is started. In order to display 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 imaging the installed screen 4 with the image sensor 5 is a screen position image 24 of FIG.

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

  The screen position of the fetched data is detected by the screen position detection unit 8.

  A first configuration of the screen position detector 8 is shown in FIG. The brightness data 14 of the captured image is input to the binarization means 15. The binarization unit 15 determines a binarization threshold value from the histogram of the entire image. For example, the threshold value is determined by a discriminant analysis method (see Non-Patent Document 1). This method examines the brightness of each pixel in the image and classifies it into two areas, a bright part and a dark part. Since the screen 4 is usually white and brighter than other parts of the screen, it 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 that is the output of the binarizing means 15 is input to the straight line detecting means 16. The straight line detection means 16 traces the boundary between the bright part and the dark part, obtains the boundary line, and divides the boundary line into straight line parts. FIG. 5 shows how four straight lines L1, L2, L3, and L4 are detected. Further, with respect to the detected straight line, the intersection detection 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 obtained.

  A second configuration of the screen position detector 18 is shown in FIG. The brightness data 14 of the captured image is input to the edge detection means 19. The edge detection means 19 compares each pixel with an adjacent pixel value, and determines that an edge exists in the pixel when the difference between the pixel values is larger than a preset threshold value. Then, an edge image as shown in FIG. 7 is obtained. Depending on the setting of the threshold, 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. Similarly to the first configuration, the intersection detection means 17 obtains intersections of adjacent ones with respect to the obtained straight line, and obtains the positions of the four corners of the screen 4.

  The detected position is located in the entire projector projection display screen image 22, and the screen distortion detection unit 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 and is transformed into a shape matching the shape of the screen, and is displayed on the display device 2 via the display device driving circuit 12. Then, it is projected and displayed on the screen 4.

( Second reference example )
As a second reference example , a case where the screen position image 24 does not fall within the range of the entire projector projection display screen image 22 after the screen position is detected can be considered (FIG. 8).

  At this time, the conventional treatment cannot provide a satisfactory image for the user. As shown in FIG. 8, as a coping method, after detecting the screen position, the image projected onto the screen 4 can be obtained by performing enlargement / reduction of the shape and moving the position within the screen. The size and position of an image that satisfies a rectangular shape and that is within the range of the entire projector projection display screen image 22 are calculated, and the image is displayed at the position of the display device 2 corresponding to the position. Thus, an image that can satisfy the user practically can be provided.

  This can be achieved by including processing for satisfying the above conditions in the screen distortion detector 9.

( Third reference example )
Regarding the attachment of the image sensor, as shown in FIG. 9 and the method of the first embodiment that is positioned in the vicinity of the projection lens 3, the image passing 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 for imaging. If the half mirror 13 is movable so as to be interrupted between the display device 2 and the projection lens 3 only when the image sensor 5 is picked up, it will not be affected by the half mirror 13 during normal use.

( First Embodiment of the Invention)
FIG. 10 shows a first embodiment of the present invention.

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

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

  When the raster scan type camera is the image sensor 5, the image capturing result from the camera is captured so that the image capturing unit 6 can recognize it as one picture. The image that can be 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.

  A factory that manufactures a projector in advance based on 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) in a projector incorporating the image sensor 5 Remember me.

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

  Next, the focus positions of the four corners on the display screen when the image is projected onto the actual screen 4 are detected by changing the focus position of the lens and comparing the focus profile, and the projector moves the screen onto the screen. Each distance to the four corners of the projected display screen can be known.

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

  First, a test pattern for measuring the focus at the four corners of the screen is a pattern as shown in FIG. 11 as a representative example. The outer periphery shows the display area of the display device 2. The screen cross-shaped test pattern is projected so as to be positioned at the four corners of the screen, and the 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 stored in the projector body. With the focus profile in FIG. 12, it is possible to detect the distance from the screen 4 at each point by detecting the focused position at the four corners of the screen. If the focus profile is slightly shifted at the four corners of the screen, the focus profile 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 and the projection lens 3 can be grasped more accurately than in the prior art.

  If the distances 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 grasped.

  Assuming that the screen 4 is a plane, the plane constituting the projected screen can be expressed by an inclination angle of the xy axis with respect to the projector. When the screen 4 has a square 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 the projected screen is distorted, it is not necessary to consider the relationship between the square screen frame and the projected screen, but only the positional relationship between the plane on which the projected screen is displayed and the projector. .

  Further, if 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 the screen 4 is assumed to be a plane, the display screen shape to be corrected can also be known.

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

  The change in the enlargement ratio is proportional to the ratio of the projection distance. For example, when the projection display is performed at a projection distance of 1 m and when the projection display is performed at a projection distance of 2 m, the enlargement ratio is doubled.

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

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

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

  The lens focus position at that time is detected by the lens focus position detector 27, whereby the distance of 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 factor. The image distortion can be corrected according to the detected screen tilt.

( Second Embodiment of the Invention)
When the screen is limited to a plane, distance detection can be performed at three points instead of four points. If the screen is assumed to be a plane, the image projection state can be expressed by the rotation of the a axis and the b axis shown in FIG. To represent rotation on the a-axis and b-axis, if two points indicating the inclination / position of the b-axis with respect to the a-axis and one point for indicating the rotation angle with respect to the b-axis are determined, the inclination can be obtained. .

( Third 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 distance detection points in a mesh shape and performing interpolation between detection points by linear interpolation or high-order curve interpolation, Automatic image distortion correction can be realized.

( Fourth embodiment of the invention)
The first to third embodiments and the first to third reference examples of the present invention described above are methods for automatically correcting the trapezoidal distortion correction caused by the tilted projection of an image. This is a method of detecting the screen position with respect to the entire position of the projection display screen of the projector using an image sensor built in the projector, and correcting the image distortion so that the projected image fits the screen. In this method, the projection display on the image sensor is performed. The entire screen needs to be detected in advance by calibration, and the entire position of the projection display screen in this case is a fixed value.

  At this time, there are a method of positioning the image sensor through the projection lens so that it is guided by a half mirror or the like, and a method of positioning in the vicinity of the projection lens in the projection direction. If the position of the projection lens does not match the imaging position of the image sensor as in the case, the overall position of the projection display screen imaged on the image sensor changes due to tilt projection, and the degree of this change is the degree of tilt projection. This is a method in which the entire position of the projection display screen is detected in advance by calibration. This is because the projection display screen does not match the actual position of the projection display screen on the image sensor at the time of projection. When detecting the position and correcting the image distortion so that the projected image fits 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 full 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 line of the entire projection display screen is located outside the screen, and it is expected that there are various objects outside the screen, so it is directly from the image captured by the image sensor. It is difficult to detect.

In the fourth embodiment of the present invention, a pattern is displayed on the screen, its position is detected, and the position of the entire projection display screen is calculated from the position, thereby detecting the position of the entire projection display screen. It can be done.

  Thereby, even if the image sensor is located away from the projection lens, the position of the entire projection display screen can be accurately detected.

Referring to FIG. 18, there is shown a projector device having an automatic image distortion correction function as a fourth embodiment of the present invention.

  1 is a light source (lamp) of a 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 directed to the projection direction to capture 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 captured by the image sensor. A projection display position detection unit that detects the display position of the projected video in the image, 8 is a screen position detection unit that detects the screen position in the image captured by the image sensor, and 41 is the position of the entire projection display screen from the result of 7. The projection display screen overall position calculation unit for calculating the screen distortion, 9 is a screen distortion detection for detecting screen distortion from the relative positions of 41 and 8. , 10 is a video input unit for inputting video projected by the projector, 11 is an image distortion correction circuit for correcting distortion based on the result of 9, and 12 is a display device drive for displaying video from 11 on the display device 2 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 fourth 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, the image sensor 5 captures an image, the image capturing unit 6 captures the captured image, and the image sensor optical distortion correction circuit 33 captures the image sensor 5. Correct optical distortion. The captured image is like a 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 by using optical distortion correction data prepared in advance. .

  Next, the position of the entire projection display screen is detected by a method in which two types of all white patterns are displayed on the inner side of the screen 4 to detect the positions and are calculated from the results.

  First, the display pattern generation unit 23 displays an all-white pattern whose length and width are 75% of the whole projector projection display screen on the screen 4, and this pattern is imaged by the image sensor 5 and the image capturing unit 6. After the captured image is taken in, and the optical distortion in the image sensor 5 is corrected by the image sensor optical distortion correction circuit 33, the position is detected by the projection display position detection unit 7, and the projection display screen overall position calculation unit 41 is detected. send. Next, the display pattern generation unit 23 displays an all-white pattern whose vertical and horizontal lengths are 50% of the entire projector projection display screen on the screen 4, and this pattern is captured by the image sensor 5. 6, the captured image is captured 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 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 boundary between the% all white display image 34 and the 50% all white display image 35, respectively, and the projection display screen whole position calculation unit In 41, the position of the entire projector projection display screen image 22 is calculated from the relative position of the 75% all white display image 34 and the 50% all white display image 35.

  Next, the display device 2 is determined from the relative positional relationship between the screen position detected by the screen position detection unit 8 in the screen distortion detection unit 9 and the position of the entire projector projection display screen image 22 detected by the projection display screen overall position calculation unit 41. Find the position of the screen 4 above. Thereby, the final target image shape of the distortion correction is known, and the image distortion correction circuit 11 performs distortion correction on the video signal from the video input unit 10 so as to obtain the final target image shape of the distortion correction detected by the screen distortion detection unit 9, and then projects. To do.

  The distortion correction means is described in the specification of Japanese Patent Application No. 2002-018407, etc., and the distortion correction is performed using the distortion correction means, and the distortion correction is performed so as to match the detected screen position. , The projector video can be projected in a manner that matches the target screen surface.

  Note that the two patterns need not have a ratio of 75% or 50%, but may not be all white.

  In the above example, two white patterns of 75% and 50% are displayed and their positions are detected to calculate the position of the entire projector projection display screen image 22. 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.

( Fourth reference example )
FIG. 22 shows a projector apparatus having an automatic image distortion correction function as a fourth reference example .

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 correction is performed once by the method of the fourth embodiment of the present invention described above, and then the image distortion is corrected. The corrected projection display position and the screen position are compared and corrected by feedback control so as to match.

In the above-described fourth 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 projection display screen image 22 calculated by the projection display screen overall position calculation unit 41, The position of the screen 4 on the display device 2 can be known and the final target image shape of the distortion correction can be known. The image distortion correction circuit 11 corrects the distortion so as to match the screen position and matches the target screen surface. If the image sensor 5 is optically distorted and cannot be corrected by the image sensor optical distortion correction circuit 33, the image 4 projected on the screen 4 and the image 4 subjected to image distortion correction coincide with each other. do not do. In other words, when optical distortion is complicated and calculation is difficult, or it is difficult to prepare optical distortion correction data in advance, for example, to measure optical distortion characteristics for each projector device to be produced and create data If it takes time and is not realistic, optical distortion correction as in the fourth embodiment described above cannot be performed.

For this reason, in this reference example, 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. Instead of the display device drive circuit 12, the generated pattern output is input to the image distortion correction circuit 11 so that the image distortion correction is applied.

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

  Next, the detected shape is reduced as shown in FIG. 23 and stored in the image distortion correction data unit 40. The image distortion correction circuit 11 performs image distortion correction based on the data stored in the image distortion correction data unit 40. The output signal of the image distortion correction circuit 11 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 the error 32 of the calculation of the overall position of the projection display screen 41 in the projection display screen overall position calculation unit 41 due to the optical distortion of the image sensor 5.

  A 100% all-white pattern, that is, a projector full-screen display image size pattern is displayed from the display pattern generation unit 23, the pattern is captured by the image sensor 5, the captured image is captured by the image capturing unit 6, and the projected display position is displayed. The detection unit 7 detects the projection display position. Here, since the output of the screen distortion detector 9 is reduced as described above, this 100% all white pattern is displayed inside the screen 4 as in the reduced display range 31 of FIG.

  When the image is not reduced, that is, when the image distortion correction is performed in the entire projector projection display screen range 38 shown in FIG. 23, the display range 30 is not reduced, and an error due to the optical distortion of the image sensor 5 at that time is optical. It becomes a portion of 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 compared. The image distortion correction data in the image distortion correction data section 40 is updated so that the value changes in a direction that matches the screen position. The projection display detected by the projection display position detection unit 7 is performed by repeatedly imaging the displayed 100% all-white pattern, detecting the projection display screen position, comparing with the screen position, and updating the image distortion data. Control is performed so that the screen position coincides with the screen position detected by the screen position detector 8. At this time, since the position of the pattern projected outside the screen cannot be detected correctly, the image distortion correction data is always updated so as to match the screen from the inside of the screen.

( Fifth embodiment of the invention)
FIG. 25 shows a fifth embodiment . In addition to the block diagram (FIG. 10) of the first embodiment, a pointer control / display unit 42 on the screen is added.

  The actual image distortion correction operation is limited by its circuit configuration, and as shown in FIG. 26, the center image 43 and the outer periphery image 44 are displayed, the screen 4 includes the center image 43, and the outer periphery portion. Have the video 44 installed so that it does not protrude. This action implicitly instructs the user the image distortion correction operation range, and when performing automatic correction, the correction operation can be performed within the circuit limit, and the image distortion correction operation limit. It will no longer be possible to perform corrections by.

  However, it is difficult to automatically detect the screen 4 when a pattern or the like is displayed on the screen 4 or an outer frame of the screen 4 or a transmissive screen is used.

  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 automatic correction is used as it is, and the four corners are instructed by the pointer, thereby performing the image correction manually, A user-friendly operation flow can be constructed, and the user can perform an image distortion correction operation in a minimum time.

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

  After the automatic adjustment is unsuccessful, a point that can be pointed is explicitly displayed at the four corners of the center image 43 to indicate that the part can be pointed. After that, the four corners of the center image 43 are matched with the four corners of the screen 4 by using the pointers provided in the apparatus, thereby associating the positions on the display screen with the four corners of the screen. The image distortion correction circuit 11 can perform correction by performing correction.

It is a figure which shows the form of the 1st reference example . It is a figure which shows the image sensor captured image example. It is a figure which shows the example of a screen position image. It is a figure which shows the 1st structure of a screen position detection part. It is a figure which shows a mode that four straight lines of L1, L2, L3, and L4 were detected. It is a figure which shows the 2nd structure of a screen position detection part. It is a figure which shows a mode that the edge image was obtained. It is a figure which shows the case where a screen position image does not enter into the range of a projector full screen display image after performing screen position detection. It is a figure which shows the 3rd reference example imaged by guide | inducing the image which passed through the projection lens to an image sensor with a half mirror. It is a figure which shows the 1st Embodiment of this invention. It is a figure which shows the test pattern for measuring the focus of four corners of a screen. It is a figure which shows the relationship (focus profile) of the focus position of the lens corresponding to the position where the distance from a projector to a screen and the projected image focused. It is a figure which shows the case where the projector and the flat screen are facing directly. It is a figure which shows the case where a flat screen inclines with respect to a projector. It is a figure which shows the case where the projector and the flat screen are facing directly. It is a figure which shows the case where a flat screen inclines with respect to a projector. If the screen is assumed to be a plane, it is a diagram showing that an image projection state can be expressed by rotation about the a-axis and the b-axis. It is a figure which shows the 4th Embodiment of this invention. It is a figure which shows the example of an image sensor captured image (a projector projection display screen whole image and a screen position image). It is a figure which shows the image sensor captured image example (75% all white display image and 50% all white display image). It is a figure which shows the image sensor image example (75% all white display image and center display image). It is a figure which shows the 4th reference example . It is a figure which shows the image on a display device. It is a figure which shows the projection image on a screen. It is a figure which shows the 5th Embodiment of this invention. It is a figure which shows having a center part image | video and an outer peripheral part image | video displayed, and having a screen installed in the form which includes a central part image | video and does not protrude an outer peripheral part image | video. It is a figure which shows performing image correction manually by using the center part image | video used at the time of automatic correction | amendment as it is, and instruct | indicating the four corners with a pointer.

Explanation of symbols

1 Light source (lamp)
2 Display device (LCD panel)
DESCRIPTION OF SYMBOLS 3 Projection lens 4 Screen 5 Image sensor 6 Image capture part 7 Projection display position detection part 8, 18 Screen position detection part 9 Screen distortion detection part 10 Image input part 11 Image distortion correction circuit 12 Display device drive circuit 13 Half mirror 14 Image Lightness 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 detection unit 27 Lens focus position detection unit 28 Distance detection unit Correction coefficient calculation unit 29 Projection display screen position-screen position comparison unit 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 Display range reduced 38 38 Image 40 Distortion correction data section 41 Projection display screen overall position calculation section 42 Pointer control / display section on screen 43 Center section video 44 Perimeter section video

Claims (3)

A projector device,
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
An image distortion correction circuit that deforms an image signal supplied to the display device,
The image sensor images the screen;
The image distortion correction circuit is configured so that the shape of the projection image generated from the supply image matches the area of the screen based on the positional relationship between the entire image on the projection display screen and the captured screen. Transforming the supply image ,
The projection lens projects a first projection display position detection pattern displayed on the display device;
The image sensor images the projected first projection display position detection pattern,
The projection lens projects a second projection display position detection pattern displayed on the display device;
The image sensor images the projected second projection display position detection pattern,
The entire projection display screen image is calculated based on the captured first and second projection display position detection patterns,
The first projection display position detection pattern includes a first white region;
The second projection display position detection pattern includes a second white region;
The first white region is a region obtained by reducing the entire display region to 3/4 each of the vertical and horizontal directions on the display device, and is located at the center of the entire display region,
The projector device according to claim 1, wherein the second white area is an area obtained by reducing the entire display area to ½ each of the vertical and horizontal directions on the display device, and is located at the center of the entire display area . A projector device,
A display device for displaying images;
A projection lens for projecting the image;
An image sensor disposed in the vicinity of the projection lens;
An image distortion correction circuit that deforms an image signal supplied to the display device,
The image sensor images the screen;
The image distortion correction circuit is configured so that the shape of the projection image generated from the supply image matches the area of the screen based on the positional relationship between the entire image on the projection display screen and the captured screen. Transforming the supply image,
The projection lens projects a first projection display position detection pattern displayed on the display device;
The image sensor images the projected first projection display position detection pattern,
The projection lens projects a second projection display position detection pattern displayed on the display device;
The image sensor images the projected second projection display position detection pattern,
The entire projection display screen image is calculated based on the captured first and second projection display position detection patterns,
The first projection display position detection pattern includes a first white region;
The projector apparatus, wherein the second projection display position detection pattern indicates a center of an entire display area of the display device. The projector device according to claim 2, wherein
The first white region is a region obtained by reducing the entire display region to 3/4 each of the vertical and horizontal directions on the display device, and is located at the center of the entire display region .

Images