Projector Keystone Correction Using Guide Area Markers
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Solution Overview
Problem
Existing projectors face challenges in accurately correcting keystone distortion when projecting images due to errors in the correction process and the need for extensive calculations, leading to distorted images on non-rectangular surfaces.
Innovation Solution
An electronic apparatus and method that performs keystone correction by using a user-set guide area, employing markers and transformation matrices to project images onto a rectangular area of maximum size corresponding to the input image's aspect ratio, utilizing a processor to identify and correct the guide area based on captured images and user input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a projector captures a projection surface using an image sensor and calculates distorted angle, then keystone correction can be performed, but correction errors significantly affect angle calculation accuracy and require extensive calculations
Solution Approach 1:
The patent introduces a guide area as an intermediary element between the projection surface and the calculation process. The guide area provides predefined reference points and geometric constraints that simplify angle calculation. Instead of directly calculating distorted angles from captured images (which requires complex correction processes), the system uses the guide area's known geometry as a mediator to derive projection parameters, significantly reducing computational complexity while maintaining accuracy.
2Manufacturing precision
If keystone correction is performed without a guide area, then projection can be done on any surface, but image distortion occurs and correction accuracy is poor
Solution Approach 1:
The patent applies preliminary action by pre-defining guide areas with known geometric properties before projection. The guide area is established in advance on the projection surface, providing predetermined reference points and constraints. This preliminary setup enables accurate keystone correction by giving the system known geometric references to work from, rather than attempting to calculate corrections from arbitrary captured images of unknown geometry.
3Measurement precision
If extensive calculations are performed for handling captured images, then angle calculation can be attempted, but processing time increases and error propagation occurs
Solution Approach 1:
The patent extracts only the essential geometric information needed for projection by using the guide area's predefined structure. Instead of performing extensive calculations on entire captured images, the system extracts key reference points from the guide area (such as corner coordinates and edge definitions) and uses these extracted elements directly for calculating projection parameters. This extraction approach minimizes processing time while maintaining accuracy by focusing computation only on necessary geometric relationships.
Data Source
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AI summary
Disclosed is an electronic apparatus. The electronic apparatus comprises: an image projection unit; and a processor which controls the image projection unit to project a test image including a plurality of markers onto a projection surface, identifies first information indicating the position of each of the plurality of markers in the test image, second information based on a captured image captured of the projection surface from an external device, and information about a guide area, and performs keystone correction so that an image corresponding to the guide area is projected based on the first information, the second information, and the information about the guide area.