Pixel Position Correspondence for Arbitrary Projection Screens
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Solution Overview
Problem
Existing methods are unable to accurately correct image distortion on projection screens with complex surface irregularities, as they are limited to planar or quadratic surfaces, failing to specify precise pixel position correspondence for arbitrary shapes.
Innovation Solution
A system that projects reference pattern image groups with continuously changing luminance values, calculates initial phase values from photographic images, and associates these with coordinates to specify correspondence between pixels in the projected image and the projection screen, enabling accurate distortion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional distortion correction methods are used, then image distortion can be corrected on planar or quadratic surfaces, but pixel position correspondence cannot be accurately specified on arbitrary-shaped screens with complex surface irregularities
Solution Approach 1:
The patent divides the projection screen into multiple coordinate systems (screen coordinate system, camera coordinate system, and projector coordinate system) and establishes transformation relationships between them. This segmentation allows accurate pixel position correspondence to be achieved on arbitrary-shaped screens by mapping positions through intermediate coordinate systems rather than attempting direct mapping.
Solution Approach 2:
The patent introduces camera coordinate system as an intermediary to establish the relationship between the projector and the screen. By using the camera's perspective as a mediator, the system can accurately map pixel positions from the projector through the camera coordinate system to the screen coordinate system, enabling precise correspondence specification on complex surface geometries.
2Ease of operation
If projection is performed from non-assumed positions or directions, then flexibility in projector placement is improved, but image distortion increases requiring complex correction mappings
Solution Approach 1:
The patent changes the parameter representation from direct pixel coordinate mapping to a multi-coordinate system transformation approach. By introducing transformation matrices between different coordinate systems (projector, camera, and screen coordinates), the system can handle various projector placements and screen geometries through parameter transformations rather than requiring complex correction mappings for each case.
Data Source
AI summary
When an image is projected on an arbitrary projection screen, correspondence between pixels in the image to be projected and pixels in projection means is specified. Reference pattern image group generating means 73 generates a reference pattern image group formed from images for each of which a luminance value defined as a function value of a continuous function which continuously changes with changes in phase is determined by varying the phase for each image, the image group being an image group having an initial phase value continuously varied on a coordinate-by-coordinate basis along one coordinate axis. Phase calculation means 75 calculates, from changes in luminance of pixels in a plurality of photographic images obtained by photographing each image of the reference pattern image group, the initial phase values that correspond to the changes in the luminance of the respective pixels in the photographic images. Associating means 76 conducts an inverse operation of a calculation instituted by the reference pattern image group generating means to derive initial phase values from coordinates, upon the calculated initial phase values, and then uses results of the inverse operation to specify correspondence between pixels in the image to be projected and pixels in projection means 71.