Image Coding Apparatus Dynamic Typical Color Selection
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Solution Overview
Problem
Conventional color palette-image coding methods require extensive calculation and memory resources to determine typical colors for image blocks, making them inefficient for hardware packaging and requiring large memory capacity.
Innovation Solution
An image coding apparatus that acquires pixel blocks, calculates distances between target pixels and pre-determined typical colors, and assigns indices based on minimum distance, reducing the need for histogram calculation and memory usage by dynamically selecting and adding new typical colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If histogram calculation is performed for all colors in the image block to determine typical colors, then color representation accuracy is improved, but memory capacity requirements increase significantly
Solution Approach 1:
The patent extracts only the necessary color information from the image block by identifying typical colors through direct pixel comparison rather than calculating histograms for all colors. This selective extraction approach maintains color representation accuracy while significantly reducing memory requirements, as only typical color values and their frequencies need to be stored rather than complete histograms for all possible colors.
Solution Approach 2:
The patent performs preliminary action by pre-determining typical colors for the image block before actual coding operations. These typical colors are established in advance through a single pass analysis, and then reused during the coding process without requiring repeated histogram calculations, thereby reducing both memory usage and computational overhead.
2Measurement precision
If histogram calculation is performed whenever one typical color is generated, then typical color determination accuracy is improved, but calculation costs increase greatly
Solution Approach 1:
The patent performs preliminary action by determining all typical colors in a single pass through the image block data. Rather than repeatedly calculating histograms whenever a typical color is generated, the system identifies typical colors upfront by comparing pixels against existing typical colors and accumulating frequency counts in one efficient operation, significantly improving calculation efficiency while maintaining accuracy.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining a continuous accumulation process for typical color frequencies during a single pass through the image data. The system continuously updates frequency counts for each typical color as pixels are processed, eliminating the need for discrete, repeated histogram calculations and thereby maintaining high calculation efficiency throughout the encoding process.
3Loss of information
If histogram is calculated for all colors in the image block, then complete color distribution information is obtained, but processing time increases
Solution Approach 1:
The patent extracts only the essential color distribution information needed for effective coding by identifying typical colors and their frequencies rather than calculating complete histograms for all possible colors. This selective extraction maintains sufficient color distribution information for accurate representation while significantly reducing processing time by avoiding unnecessary calculations for colors that do not represent significant portions of the image.
Solution Approach 2:
The patent applies partial action by calculating color distribution information only for typical colors that actually appear in the image block rather than computing histograms for all possible colors in the color space. This partial calculation approach provides sufficient color distribution information for effective compression while dramatically reducing processing time by focusing computational resources only on relevant colors.
Data Source
AI summary
According to one embodiment, an acquisition unit acquires a pixel block having a predetermined size from image data to be coded. A comparison unit calculates a distance between a color of a target pixel in the pixel block and each of a plurality of typical colors, and selects a typical color of which the distance is a minimum distance from the plurality of typical colors. A decision unit assigns a first index representing the selected typical color to the target pixel if the minimum distance is smaller than a first threshold, assigns a second index representing a new typical color to the target pixel if the minimum distance is larger than the first threshold, and adds the color of the target pixel as the new typical color when the second index is assigned. A coding unit codes the selected typical color, the new typical color, the first index and the second index.