Optics: image projectors – Distortion compensation – For projection axis inclined to screen
Reexamination Certificate
2000-11-27
2002-12-31
Dowling, William (Department: 2851)
Optics: image projectors
Distortion compensation
For projection axis inclined to screen
C353S101000
Reexamination Certificate
active
06499847
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a projection system and a projector for imaging a projected image using an imaging portion.
2. Description of Related Art
When presenting of an image by projecting the image onto a screen or the like using a projector (projective type display apparatus), the person who explains the projected image does so in front of the image by indicating the projected image using an indicating stick, a laser pointer or the like.
In such a presentation, the projected image and the designated image on the projected image are taken using a CCD camera or the like. In the image taken, the shadow of the indicating stick or fingers is detected as a low luminance region. From the configuration of the shadow, a pointing position is detected, or by detecting a high luminance region of the laser pointer, a pointing position is detected, whereby a cursor or a predetermined image is displayed in the projected image corresponding to the pointing position, or a predetermined program processing corresponding to the pointing position is performed to display the resulting image, thereby providing a presentation system for supporting presentations.
SUMMARY OF THE INVENTION
In the case of the above apparatus, when a dedicated screen is used as a portion onto which projection is performed, there is no problem since the diffusability of light is high. When, however, a portion onto which images are to be projected that includes a highly reflective member in its surface, such as a white board, is used as a screen, a high luminance region called hot spot may be generated on the white board, depending upon the position from which the image is viewed. This hot spot is a high luminance portion in the projected image which can be seen when the light source image of the light source lamp of the projector is reflected by the screen including the highly reflective member.
Thus, depending upon the position of the CCD camera, there is an influence of the hot spot. When detecting the pointing position from the distribution of the variation in luminance in the projected image, the detection of the pointing position cannot be correctly done due to the hot spot reflected light, and in some case, various proceedings based on the image taking result may not be correctly conducted.
The present invention has been made in view of the above problem. It is accordingly an object of the present invention to provide a projection system and a projector capable of reducing the influence of the hot spot and capable of processing image taking data in a satisfactory manner.
In accordance with the present invention, to achieve the above object, there is provided a projection system which may consist of a projecting portion for projecting image light onto a predetermined projection receiving portion, an image taking portion for taking a projected image obtained by the projecting portion, and a processing portion for performing a predetermined processing based on the image taking result obtained by the image taking portion, wherein an image taking lens of the image taking portion is arranged outside the reflection region of the direct reflection light of the projected image.
In accordance with the present invention, to achieve the above object, there is provided a projector which may consist of a projecting portion for projecting image light onto a predetermined projection receiving portion, and an image taking portion for taking a projected image obtained by the projecting portion, wherein an image taking lens of the image taking portion is arranged outside the reflection region of the direct reflection light of the projected image.
In these inventions, the projection light projected by the projecting portion is directly reflected by the projection receiving portion (screen) and the reflected light returns to the projecting portion, the image taking lens for taking the projected image projected onto the projection receiving portion being arranged outside the reflection region of the returning reflected light, whereby the influence of the hot spot is reduced, and it is possible to obtain correct image taking data and to process the image taking data in a satisfactory manner. In particular, as in a CCD camera, the image taking portion converts light intensity (luminance) to an electric signal, so that when the reflection of the hot spot enters the image taking area of the CCD, that portion alone exhibits high luminance, and it is difficult to detect the pointing position indicated by the person who explains in front of the screen. In the present invention, however, it is designed such that the reflection from the projection receiving portion is not taken in by the image taking lens, so that the image recognition by image taking is correct.
As the predetermined processing, for example, the position of indication on the projection receiving portion is detected by an indicating stick, a laser pointer or the like indicated in the projected image.
Preferably, the projecting portion includes a projection optical system, and when the projection optical system is a gate projection optical system which projects projection light upwardly, the image taking lens of the image taking portion is arranged at a position lower than the lower end of the projection region by the projecting portion, and when the projection optical system is a gate projection optical system which projects projection light downwardly, the image taking lens of the image taking portion is arranged at a position higher than the upper end of the projection region by the projecting portion.
Due to this arrangement, the image taking lens is arranged outside the reflection region of the reflected light obtained through direct reflection of the projection light at the projection receiving portion, and even when an image is projected onto a projection receiving portion formed of a highly reflective member, it is possible to reduce the influence of the hot spot, obtain correct image taking data, and process the image taking data in a satisfactory manner.
In an embodiment, the projecting portion and the image taking portion are formed integrally.
In this arrangement, the projecting portion and the image taking portion are formed integrally, whereby the position and angle of each portion can be easily adjusted.
Preferably, with respect to the optical axis of the projecting portion, the image taking angle of the image taking lens can be adjusted.
In this arrangement, even when the position of the projecting portion and the projection angle are changed, the image taking portion can be adjusted accordingly, whereby it is possible to correctly obtain the image taking data.
Preferably, the projection receiving portion is formed of a highly reflective material having a predetermined reflectance.
In this arrangement, even when an image is projected onto a projection receiving portion formed of a highly reflective material which is subject to generation of a hot spot, it is possible to reduce the influence of the hot spot, obtain correct image taking data, and process the image taking data in a satisfactory manner.
Examples of the projection receiving portion include a white board and a concrete wall.
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Dowling William
Oliff & Berridg,e PLC
Seiko Epson Corporation
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