Projector Color Calibration Using Reference Image Comparison
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Solution Overview
Problem
Existing projector systems face difficulties in adjusting projection image colors accurately during readjustment, especially when obstacles like chairs or tables are placed in front of the screen, as cameras need to be positioned directly in front for initial adjustments, making subsequent adjustments challenging due to varying projection light colors with observation angles.
Innovation Solution
A method involving a first generation step of projecting a test pattern by a projector and capturing the image with a camera to generate a reference image, followed by a second generation step of projecting the test pattern to generate a comparative image, and using correction data to adjust the projection conditions so that the comparative image matches the reference image, allowing for accurate color readjustment without requiring cameras to be positioned directly in front of the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cameras are positioned directly in front of the screen for initial adjustment, then color accuracy is improved, but device complexity and ease of operation deteriorate when obstacles like chairs or tables are present
Solution Approach 1:
The system performs preliminary color calibration by capturing a reference image at the optimal camera position (directly in front of the screen) during initial setup. This reference image stores the correct color information, allowing subsequent readjustments to be performed from any position by comparing against this pre-captured reference, eliminating the need to physically reposition the camera during maintenance operations.
Solution Approach 2:
The system creates a digital copy of the reference projection image captured at the optimal position. This reference image serves as a template that can be compared against images taken from any position during readjustment. The color correction is achieved by comparing the comparative image against this copied reference, allowing accurate color adjustment without requiring the camera to be physically present at the original position.
2Ease of operation
If cameras are repositioned to accommodate obstacles during readjustment, then ease of operation is improved, but measurement precision deteriorates due to varying projection light colors with observation angles
Solution Approach 1:
The system implements a feedback mechanism where the camera captures a comparative image from the current position (even if obstructed or at an angle), compares it against the stored reference image, and automatically calculates color correction values. This feedback loop allows the system to compensate for angular color variations through computational correction, maintaining accuracy regardless of camera position or obstacles present.
Solution Approach 2:
The system changes the approach from physically adjusting camera position to adjusting color parameters computationally. By capturing images at different positions and comparing against the reference, the system calculates the necessary color parameter changes to compensate for angular variations. This allows readjustment from any position while maintaining color accuracy through parameter correction rather than positional adjustment.
3Adaptability or versatility
If multiple cameras are used to capture images from different positions, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system makes the single camera universal by enabling it to perform both reference capture and readjustment functions from any position. The same camera hardware is used for initial reference image capture and for subsequent comparative image capture during readjustment, regardless of obstacles or positioning. This multi-functional use of the single camera eliminates the need for multiple cameras while maintaining adaptability to various operational scenarios.
Data Source
AI summary
A method of controlling a display system includes a first generation step of projecting a test pattern in a reference state in which a projection condition of a first projector is adjusted so that a color of a first projection image when viewed from the front becomes a desired color, and taking the first projection image corresponding to the test pattern by a first camera to generate a first reference image, a second generation step of projecting the test pattern and then taking the projection image corresponding to the test pattern by the first camera to generate a first comparative image, a third generation step of generating first correction data for correcting the projection condition so that the first comparative image coincides with the first reference image, and a correction step of correcting the projection condition based on the first correction data.