Projector Distortion Correction via Shift and Zoom Parameter Tracking
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Solution Overview
Problem
Existing projector technologies face challenges in accurately correcting image distortion when displaying images on projection surfaces due to the lack of consideration for image display areas, specifically the shift and zoom positions of the projection system, which results in distorted images with incorrect aspect ratios.
Innovation Solution
An image processing device that determines target display areas based on current shift and zoom positions of the projection system, generates corrected image data by forming a target distorted image in a target formation area, and adjusts the projection system to ensure accurate distortion correction and full image display on the projection surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low-angle image projection is used, then the projector can display images on projection surfaces from a non-vertical angle, but the resulting images suffer from distortion and incorrect aspect ratios
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the relationship between projection angles and corresponding display areas in a table before actual projection. The image processing section retrieves the appropriate display area from this pre-prepared table based on the current projection angle, enabling quick distortion correction without real-time complex calculations. This resolves the contradiction by maintaining projection angle adaptability while achieving accurate distortion correction through advance preparation.
Solution Approach 2:
The patent uses copying by creating a virtual model of the projection geometry relationships. A reference display area is defined, and its relationship with the image formation area is established as a template. This reference relationship is then copied and applied to correct distortion for various projection angles by retrieving corresponding display areas from the pre-calculated table, eliminating the need for complex real-time geometric calculations while maintaining accuracy.
2Device complexity
If distortion correction is applied without considering image display areas, then the processing is simpler, but the correction accuracy is insufficient and aspect ratios become incorrect
Solution Approach 1:
The patent resolves this contradiction by performing preliminary calculation and storage of display area information in a table. The image processing section simply retrieves pre-calculated display areas based on projection angles, avoiding complex real-time calculations while ensuring high correction precision through accurate pre-computed geometric relationships.
Solution Approach 2:
The patent introduces an intermediary element - the display area table - that mediates between the projection angle input and the distortion correction output. This table serves as a lookup intermediary that contains pre-computed relationships, simplifying the processing while maintaining high precision through accurate geometric calculations performed in advance.
3Device complexity
If the projection system shift and zoom positions are not considered, then the image processing is simpler, but the target display area determination is inaccurate
Solution Approach 1:
The patent applies universality by designing the display area table to handle multiple parameters (projection angles, shift positions, zoom positions) in a unified structure. The image processing section retrieves display areas based on the current state of these parameters without needing separate processing logic for each parameter, simplifying the system while maintaining accurate determination of display areas considering all parameter variations.
Data Source
AI summary
An image processing device for a projector including an image formation section that emits light of an image, and a projection system that projects the emitted light onto a projection surface. The image processing device includes: a target display area determination section that determines, in a display area serving as a reference on the projection surface, based on a current value of a parameter, any of target display areas set for values possibly taken by the parameter within an allowable range to be targeted on a distortion-free image for display on the projection surface; a reference formation area determination section that determines, corresponding to the reference display area, based on information about a projection angle of the projector with respect to the projection surface, a reference formation area to be formed with a virtual distorted image that is supposed to be formed in the image formation section when the distortion-free image is displayed in the reference display area; and a correction application section that generates corrected image data for supply to the image formation section by correcting any provided original image data to form a target distorted image in a target formation area, which corresponds to the target display area as is defined by a relationship between the reference display area and the reference formation area, and is formed with the target distorted image that is supposed to be formed in the image formation section when the distortion-free image is displayed in the reference display area.