Luminance Correction Circuit for Multiscreen Display Overlap Uniformity
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Solution Overview
Problem
Existing multiscreen display systems face issues with uneven luminance correction, particularly when optical distortion occurs, leading to conspicuous luminance variations in overlapping image areas, and existing solutions result in large circuit scales and image quality deterioration.
Innovation Solution
A multiscreen display system employing a luminance correction circuit with a non-linear arrangement of gain coefficients for gradation control in picture element units, which adjusts display positions and luminance levels to maintain uniform luminance distribution across overlapping areas, even with optical distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If geometric distortion correction circuit is used to correct distortion when projecting onto a planar screen, then optical distortion can be corrected, but circuit scale becomes large and image quality deteriorates
Solution Approach 1:
The invention extracts only the necessary luminance correction function from the complex geometric distortion correction circuit. By using a simple LUT (Look-Up Table) that stores predetermined correction values corresponding to image coordinates, the system achieves optical distortion correction without requiring large-scale geometric distortion correction circuits, thus reducing circuit scale while maintaining correction effectiveness.
Solution Approach 2:
The invention changes the correction approach from geometric parameter adjustment to luminance parameter adjustment. Instead of correcting distortion through geometric transformation, the system uses a LUT to adjust luminance values based on predetermined correction data, thereby avoiding the complexity of geometric distortion correction circuits while achieving the desired correction effect.
2Productivity
If electrical gradation control is carried out at intervals of fixed number of picture elements, then gradation conversion can be implemented, but conspicuousness of uneven luminance in overlapping regions cannot be eliminated
Solution Approach 1:
The invention segments the correction approach by dividing the image into multiple regions (first through fourth regions) with different correction characteristics. By applying different gradation conversion processing to different regions based on their overlap characteristics, the system achieves both efficient processing and uniform luminance correction, eliminating the conspicuousness of uneven luminance in overlapping regions.
Solution Approach 2:
The invention applies local quality by using different correction strategies for different image regions. In non-overlapping regions, standard correction is applied, while in overlapping regions, enhanced correction with smaller coefficient changes is used. This localized approach ensures luminance uniformity where needed most while maintaining overall processing efficiency.
3Manufacturing precision
If gradation conversion coefficients are determined according to distance from image edges, then luminance distribution can be corrected, but uneven luminance in overlapping areas persists when optical distortion occurs
Solution Approach 1:
The invention uses preliminary action by pre-calculating and storing correction values in a LUT that accounts for optical distortion effects. The LUT contains predetermined correction values that have been pre-adjusted to compensate for the non-linear luminance changes caused by optical distortion, allowing the system to achieve accurate correction without real-time calculation complexity.
Solution Approach 2:
The invention uses copying by creating a corrected version of the image data through LUT-based luminance adjustment. Instead of directly modifying the original image, the system copies the image data and applies correction to the copy, preserving the original while achieving the desired luminance uniformity even under optical distortion conditions.
Data Source
AI summary
Picture signals that indicate a screen that are supplied as output from a signal generation source are divided by a picture splitting device into picture signals of a plurality of screens for displaying a large screen and then supplied to a gradation conversion LUT unit in a luminance correction circuit. Based on display position information from a timing circuit, a coefficient arrangement control unit implements a non-linear arrangement of gain coefficients for gradation control that is carried out in picture element units. Based on the display position information from the timing circuit, the gradation conversion LUT unit adjusts display positions such that areas in which the projected display areas of the plurality of projectors overlap match with areas that are the objects of gradation conversion, and implements a luminance level conversion in picture element units of input signal levels of picture signals that have been split using the arrangement of gain coefficients for gradation control.