Pixel Overdrive Compression Using Decimation and Gradient Encoding
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Solution Overview
Problem
Existing pixel overdrive systems in electronic devices, such as LCDs, face challenges in reducing storage requirements while avoiding artifacts like banding, color shifts, and shimmering, particularly when compressing and decompressing frames for overdrive operations.
Innovation Solution
The implementation of a unique combination of decimation and gradient encoding for image compression, which allows for significant storage reduction in frame buffers without decompressing the current frame during overdrive operations, thereby preventing propagation of compression errors and ensuring accurate overdrive outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If frame compression is applied to reduce storage requirements, then storage needs are reduced, but compression errors propagate and cause display artifacts
Solution Approach 1:
The patent segments the frame buffer into multiple independently compressed tiles instead of compressing the entire frame as a single unit. Each tile is processed and stored separately, which limits the propagation of compression errors to only the affected tile region rather than the entire frame. This segmentation approach maintains significant compression ratios while reducing artifact propagation.
Solution Approach 2:
The patent applies different compression strategies to different regions of the frame based on local characteristics. Motion-compensated prediction is used for dynamic regions while static regions use different encoding. This local adaptation optimizes compression efficiency in each region while minimizing artifacts in areas where they would be most noticeable.
2Measurement precision
If decompression is performed during overdrive operations, then accurate pixel comparison is achieved, but processing time and complexity increase
Solution Approach 1:
The patent performs preliminary compression of the frame buffer data before overdrive operations are needed. The compressed data is stored in advance, and during overdrive operations, the system works with the pre-compressed data structure rather than decompressing first. This preliminary preparation reduces the time required during actual overdrive operations while maintaining the ability to perform accurate comparisons through the compressed representation.
Solution Approach 2:
The patent creates and works with a compressed copy of the frame buffer data rather than requiring the full uncompressed data during overdrive operations. This compressed copy contains sufficient information for pixel comparison through clever encoding schemes, eliminating the need for time-consuming decompression while maintaining comparison accuracy.
3Quantity of substance
If full frame compression is applied, then storage requirements are minimized, but artifact propagation increases
Solution Approach 1:
The patent divides the frame into multiple independent tiles that are compressed separately. This segmentation prevents compression artifacts from propagating across the entire frame, as errors in one tile do not affect other tiles. Each tile can be independently encoded and decoded, limiting artifact propagation to local regions only.
Solution Approach 2:
The patent applies compression selectively to different portions of the frame rather than uniformly compressing everything. By applying motion compensation and prediction only where needed, and using simpler encoding for static regions, the system achieves good compression ratios without excessive artifacts in all areas.
Data Source
AI summary
Aspects of the subject technology relate to display circuitry including pixel overdrive circuitry. The pixel overdrive circuitry includes a compression engine that compresses a previous display frame, for storage and comparison to a current display frame without compression or decompression of the current display frame. The compression engine compresses the previous frame in such a way that the maximum compression error is always known and can be used to determine whether to perform overdrive operations for the current frame without compressing and decompressing the current display frame. The compression engine selects gradient encoding or decimation encoding for the compression of the previous display frame and can perform successive decimation operations within the gradient encoding operations to help reduce the size of the compressed previous frame while maintaining the quality of the ultimate overdriven current frame.