Abstract: A projector for enlarging and projecting the display image on a light valve onto a screen is provided with: an infrared photodetector for photodetecting infrared light that is emitted by an electronic pen that is manipulated on the screen and that is provided with an infrared light emission device and ultrasonic generator; at least two ultrasonic receivers for detecting ultrasonic waves that are emitted by the electronic pen; means for measuring the distance to a screen; and means for supplying coordinate data in which the position of the electronic pen on the screen, which has been calculated based on output of the infrared photodetector, output of the ultrasonic generator, and output of the means for measuring the distance to the screen, has been normalized by the length of a side of a projected rectangular image that has been enlarged and projected.

Abstract: A luminance correcting apparatus has a sensor for detecting luminances of reflected lights of projected lights individually in each of at least two colors which are reflected from a screen, a first memory for storing information representing luminances of the reflected lights in the respective colors which are detected by the sensor, a second memory for storing information representing predetermined reference luminances of the reflected lights in the respective colors, and a luminance correcting data generator for generating luminance correcting data by comparing the information stored in the first memory and the information stored in the second memory.

Abstract: An electronic whiteboard system has light emitting elements mounted on ultrasonic wave receivers of a signal processor, and an imager device for imaging the light emitting elements and a projection test pattern of a projector to acquire a positional relationship between the light emitting elements and an image projected from the projector. The electronic whiteboard system can facilitate initialization of the coordinates with the acquired positional relationship.

Abstract: A projector has an acceleration sensor for detecting a tilt angle of the projector, a manual controller for manually setting a correction amount for a keystone distortion correction, an auto/manual switch, an upper edge basis corrector for determining parameters for an upper edge basis keystone distortion correction, a lower edge basis corrector for determining parameters for a lower edge basis keystone distortion correction, and an image processor for performing a keystone distortion correction on the image on the basis of the upper edge or lower edge in accordance with parameters applied thereto from the upper edge basis corrector or lower edge basis corrector to display the corrected image on a liquid crystal panel or the like. As the auto/manual switch selects an automatic adjustment, the acceleration sensor and upper edge basis corrector are connected to the image processor. As a manual adjustment is selected, the manual controller and lower edge basis corrector are connected to the image processor.

Abstract: The present invention is addresses to the conventional problem that when the distortion of a projected image that is obliquely projected onto a screen is corrected, an imaging device that is installed near a projection lens for performing an electronic blackboard function directly captures the distortion-corrected image but fails to perform the electronic blackboard function. According to the present invention, an image which is distorted from a rectangular shape into a horizontal and trapezoidal shape in a direction opposite to the direction of the distortion on the screen is displayed on a light bulb and projected through the projection lens. The distortion of the image displayed on the screen is corrected, and the image is visually perceived as a corrected projected image having a rectangular profile. At this time, the imaging device which has captured the corrected projected image outputs a captured image.

Abstract: A projector for enlarging and projecting the display image on a light valve onto a screen is provided with: an infrared photodetector for photodetecting infrared light that is emitted by an electronic pen that is manipulated on the screen and that is provided with an infrared light emission device and ultrasonic generator; at least two ultrasonic receivers for detecting ultrasonic waves that are emitted by the electronic pen; means for measuring the distance to a screen; and means for supplying coordinate data in which the position of the electronic pen on the screen, which has been calculated based on output of the infrared photodetector, output of the ultrasonic generator, and output of the means for measuring the distance to the screen, has been normalized by the length of a side of a projected rectangular image that has been enlarged and projected.

Abstract: The projection display device stores, in a frame memory, a shot image of a test pattern for cases where the obstacle is not represented in the region of the projection; compares, at a comparison unit, a shot image of the test pattern for the case where the obstacle is represented in the region of the projection, with the stored shot image of the test pattern in order to detect an obstacle present in the region of the projection; generates, at an image-mask enlargement-processing unit, an image mask section having a region larger than the region of the detected obstacle; and effects, at a luminance control unit, a control to reduce the luminance in the image mask section.

Abstract: A projector having a tilt angle measurement device is provided with: a projection device for projecting an image onto a projection surface; a tilt angle measurement device for calculating the tilt angle that is formed between the axis of projection of the projection device and the projection surface; and an image control unit for controlling the output image from the projection device in accordance with the tilt angle that is calculated and thus correcting distortion in the image that is projected onto the projection surface.

Abstract: A projector has a distortion correcting circuit for correcting a distorted quadrangular projected image, which is projected onto a projection surface along a projection optical axis inclined in at least one of leftward, rightward, upward, and downward directions, into a rectangular corrected image, such that one of the vertexes B, D on the opposite ends of either one of two diagonal lines of the rectangular corrected image is positioned on one side La of the outer edge of a projection range of the projected image and the other vertex on another side Lb that is positioned adjacent to the one side La.

Abstract: A projection type display device includes a distortion corrector for correcting a projected image for distortions when the image is projected with a projection optical axis tilted with respect to a screen. The distortion corrector comprises a tilt angle generator for finding a tilt angle of the projection optical axis, and a display image corrector for correcting the display image using the tilt angle. The display image corrector comprises a two-dimensional table for storing corrected coordinates for four vertexes of the display image employing a vertical tilt angle and a horizontal tilt angle as variables, and a fixed point determiner for selecting one of the four vertexes as a fixed point.

Abstract: A projector for enlarging and projecting the display image on a light valve onto a screen is provided with: an infrared photodetector for photodetecting infrared light that is emitted by an electronic pen that is manipulated on the screen and that is provided with an infrared light emission device and ultrasonic generator; at least two ultrasonic receivers for detecting ultrasonic waves that are emitted by the electronic pen; means for measuring the distance to a screen; and means for supplying coordinate data in which the position of the electronic pen on the screen, which has been calculated based on output of the infrared photodetector, output of the ultrasonic generator, and output of the means for measuring the distance to the screen, has been normalized by the length of a side of a projected rectangular image that has been enlarged and projected.

Abstract: A luminance correcting apparatus has a sensor for detecting luminances of reflected lights of projected lights individually in each of at least two colors which are reflected from a screen, a first memory for storing information representing luminances of the reflected lights in the respective colors which are detected by the sensor, a second memory for storing information representing predetermined reference luminances of the reflected lights in the respective colors, and a luminance correcting data generator for generating luminance correcting data by comparing the information stored in the first memory and the information stored in the second memory.

Abstract: An electronic whiteboard system has light emitting elements mounted on ultrasonic wave receivers of a signal processor, and an imager device for imaging the light emitting elements and a projection test pattern of a projector to acquire a positional relationship between the light emitting elements and an image projected from the projector. The electronic whiteboard system can facilitate initialization of the coordinates with the acquired positional relationship.

Abstract: A projector has a distortion correcting circuit for correcting a distorted quadrangular projected image, which is projected onto a projection surface along a projection optical axis inclined in at least one of leftward, rightward, upward, and downward directions, into a rectangular corrected image, such that one of the vertexes B, D on the opposite ends of either one of two diagonal lines of the rectangular corrected image is positioned on one side La of the outer edge of a projection range of the projected image and the other vertex on another side Lb that is positioned adjacent to the one side La.

Abstract: A projector for enlarging and projecting the display image on a light valve onto a screen is provided with: an infrared photodetector for photodetecting infrared light that is emitted by an electronic pen that is manipulated on the screen and that is provided with an infrared light emission device and ultrasonic generator; at least two ultrasonic receivers for detecting ultrasonic waves that are emitted by the electronic pen; means for measuring the distance to a screen; and means for supplying coordinate data in which the position of the electronic pen on the screen, which has been calculated based on output of the infrared photodetector, output of the ultrasonic generator, and output of the means for measuring the distance to the screen, has been normalized by the length of a side of a projected rectangular image that has been enlarged and projected.

Abstract: Projector has projection optical system for projecting an image onto a projection surface and optical zoom mechanism for actuating projection optical system to enlarge and reduce the image projected onto the projection surface. Projector also has distortion correcting circuit for correcting distorted quadrilateral projected images, which are projected onto the projection surface along an optical axis that is oblique vertically and horizontally to the projection surface, into respective square corrected images, zoom setting detector for detecting a zoom setting of optical zoom mechanism, and CPU for generating corrective data to be set in distortion correcting circuit based on the zoom setting detected by zoom setting detector.

Abstract: The present invention is addresses to the conventional problem that when the distortion of a projected image that is obliquely projected onto a screen is corrected, an imaging device that is installed near a projection lens for performing an electronic blackboard function directly captures the distortion-corrected image but fails to perform the electronic blackboard function. According to the present invention, an image which is distorted from a rectangular shape into a horizontal and trapezoidal shape in a direction opposite to the direction of the distortion on the screen is displayed on a light bulb and projected through the projection lens. The distortion of the image displayed on the screen is corrected, and the image is visually perceived as a corrected projected image having a rectangular profile. At this time, the imaging device which has captured the corrected projected image outputs a captured image.

Abstract: A projector has an acceleration sensor for detecting a tilt angle of the projector, a manual controller for manually setting a correction amount for a keystone distortion correction, an auto/manual switch, an upper edge basis corrector for determining parameters for an upper edge basis keystone distortion correction, a lower edge basis corrector for determining parameters for a lower edge basis keystone distortion correction, and an image processor for performing a keystone distortion correction on the image on the basis of the upper edge or lower edge in accordance with parameters applied thereto from the upper edge basis corrector or lower edge basis corrector to display the corrected image on a liquid crystal panel or the like. As the auto/manual switch selects an automatic adjustment, the acceleration sensor and upper edge basis corrector are connected to the image processor. As a manual adjustment is selected, the manual controller and lower edge basis corrector are connected to the image processor.

Abstract: The projection display device stores, in a frame memory, a shot image of a test pattern for cases where the obstacle is not represented in the region of the projection; compares, at a comparison unit, a shot image of the test pattern for the case where the obstacle is represented in the region of the projection, with the stored shot image of the test pattern in order to detect an obstacle present in the region of the projection; generates, at an image-mask enlargement-processing unit, an image mask section having a region larger than the region of the detected obstacle; and effects, at a luminance control unit, a control to reduce the luminance in the image mask section.

Abstract: A projector having a tilt angle measurement device is provided with: a projection device for projecting an image onto a projection surface; a tilt angle measurement device for calculating the tilt angle that is formed between the axis of projection of the projection device and the projection surface; and an image control unit for controlling the output image from the projection device in accordance with the tilt angle that is calculated and thus correcting distortion in the image that is projected onto the projection surface.