Lookup Table Color Conversion Using Matrix Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing color matching processing methods for image signals in non-standard color spaces degrade image quality due to interpolation calculations when primary colors like white do not coincide with lookup table grid points.
Innovation Solution
An image processing apparatus and method that assigns primary colors directly to grid points in a lookup table using two matrices to convert image signals from a uniform color space to the color space of an output device, eliminating the need for interpolation calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lookup table is used for color space conversion, then processing time is reduced, but image quality degrades when primary colors do not coincide with grid points due to interpolation calculation
Solution Approach 1:
The patent pre-calculates and stores exact color values for primary colors (white, red, green, blue) at specific grid points in the lookup table before actual color conversion operations. This preliminary preparation ensures that when these primary colors need to be converted, their exact values are directly available from the table without requiring interpolation, thus maintaining both high processing speed and accurate color reproduction.
2Productivity
If interpolation calculation is used to obtain primary color values from lookup table grid points, then processing is faster, but color fidelity is lost
Solution Approach 1:
The patent introduces an intermediary preprocessing step that calculates and stores the exact color space values for primary colors at predetermined grid points in the lookup table. This intermediary data layer acts as a bridge between the general-purpose lookup table structure and the specific requirement for accurate primary color values, allowing fast direct retrieval without interpolation while maintaining color fidelity.
3Ease of manufacture
If standard color space assignment is used, then lookup table generation is simplified, but support for non-standard color spaces is lost
Solution Approach 1:
The patent applies local quality by treating different regions of the color space differently: for primary colors (white, red, green, blue), it ensures exact grid point alignment and direct value storage; for other colors, it allows standard interpolation methods. This localized approach maintains simplicity where possible while providing enhanced accuracy where needed, and supports both standard and non-standard color spaces through the flexible matrix transformation approach.
Data Source
AI summary
An image processing apparatus decides a grid point coordinate on a lookup table corresponding to a predetermined color; calculates, based on association between a signal of the predetermined color in the uniform color space designated by a first color space information and the decided grid point coordinate, a first matrix for converting each signal in the uniform color space into a grid point coordinate; calculates, based on association between the signal of the predetermined color in the uniform color space designated by a second color space information and the decided grid point coordinate, a second matrix for converting each grid point coordinate into a signal in the uniform color space; and generates a lookup table for converting each grid point coordinate into a signal in the second color space by using the second matrix and the second color space information.