Color Conversion Device Using Dual LUTs for Storage Reduction
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Solution Overview
Problem
Conventional image processing devices require large storage capacity for color conversion lookup tables (LUTs) to maintain accuracy, but reducing LUT data capacity leads to decreased accuracy in color conversion, especially when multiple devices perform parallel processing.
Innovation Solution
A color conversion device and method that utilize two types of color conversion tables with different information amounts, allowing for parallel processing and reconversion of pixels based on attribute information to maintain accuracy while reducing storage capacity, by using a first color conversion table with more gradations for natural images and a second table with fewer gradations for image contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple LUTs are stored in each image processing device for parallel color conversion, then color conversion accuracy is maintained, but storage capacity requirements increase significantly
Solution Approach 1:
The invention segments the color conversion process into two distinct stages: a first color conversion process that operates on all pixels using a first LUT, and a second color conversion process that operates only on specific pixels (those requiring higher accuracy) using a second LUT. This segmentation allows the system to reduce overall storage requirements while maintaining accuracy where needed.
Solution Approach 2:
The invention applies local quality by differentiating the color conversion accuracy applied to different regions or types of pixels. Specifically, the second LUT with higher precision is applied selectively to pixels that require it (determined by attribute information), while other pixels use the first LUT. This ensures high accuracy is maintained locally where necessary without unnecessarily increasing storage capacity globally.
2Quantity of substance
If LUT data capacity is reduced to decrease storage requirements, then storage capacity is reduced, but color conversion accuracy decreases
Solution Approach 1:
The invention introduces dynamics by making the color conversion process adaptive based on pixel attributes. The system dynamically selects which LUT to apply to each pixel based on attribute information, allowing the color conversion accuracy to be adjusted dynamically rather than using a fixed approach for all pixels. This dynamic selection enables the system to optimize between storage capacity and accuracy on a per-pixel basis.
Solution Approach 2:
The invention changes parameters by using two LUTs with different precision levels (different information amounts) and selectively applying them based on pixel attributes. This parameter change approach allows the system to vary the color conversion precision parameter according to the specific needs of different pixels, thereby reducing overall storage requirements while maintaining necessary accuracy.
3Productivity
If parallel color conversion is performed by multiple image processing devices, then processing speed increases, but total storage capacity across all devices increases massively
Solution Approach 1:
The invention segments the LUT storage requirement across multiple devices by implementing the two-stage color conversion process in each device. Each device stores only two LUTs (first and second) instead of multiple complete LUTs, and the segmentation of the color conversion process allows parallel processing while reducing the storage burden on each individual device and the system as a whole.
Data Source
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AI summary
In order to achieve both color conversion precision and reduction in the required storage area capacity for color conversion, a color conversion unit (22) comprises: color conversion processing units (223a, 223b, 223c, 223d) that perform color conversion in parallel on colors for pixels included in each row of prescribed rows of image data input by an input unit (221) ; an attributes acquisition unit (225) that obtains the attributes information for each pixel; and a re-conversion unit (226) that re-converts the pixels after color conversion, on the basis of the attributes information. A second color conversion table used by the color conversion processing units (223b, 223c, 223d) has less information than a first color conversion table used by the color conversion processing unit (223a) for color conversion. The re-conversion unit (226) converts pixels that have been color converted using the second color conversion table inside a prescribed pixel area included in the image data for the prescribed rows, by using the pixels that have been color converted using the first color conversion table inside the prescribed pixel area.