Panel Self Refresh Controller for Lossless Still Image Compression
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Solution Overview
Problem
The existing display devices with Panel Self-Refresh (PSR) technology face challenges in reducing the size of the remote frame buffer while preventing loss of original image data, leading to increased manufacturing costs and difficulty in incorporating the buffer within the sink unit, and there is a need for a method to efficiently compress images within limited hardware capacity.
Innovation Solution
A display device with an eDP interface that includes a still image detector, a compressor for lossless data compression, and a PSR controller to analyze input images, compress still images using a stored algorithm, and determine if the compressed data can fit within the frame buffer, activating the PSR mode only when the compressed data size is equal to or less than the buffer size, thereby reducing power consumption and preventing data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a large-size remote frame buffer is used to store original image data for PSR mode, then power consumption is reduced and battery life is extended, but manufacturing costs increase and it becomes difficult to incorporate the buffer in the sink unit
Solution Approach 1:
The patent extracts only the essential data needed for PSR operation by transmitting differential data (changes between frames) rather than complete original image data. This allows the remote frame buffer to be smaller since it only needs to store differential information and a reference frame, not the entire original image data, thereby reducing manufacturing costs and complexity while maintaining power-saving functionality
Solution Approach 2:
The patent changes the data representation parameter from storing complete image data to storing differential data (changes). By transmitting only the differences between current and reference frames, the data size is significantly reduced, enabling a smaller remote frame buffer that can be incorporated in the sink unit while still achieving power consumption reduction through PSR mode
2Ease of manufacture
If the remote frame buffer size is reduced to lower manufacturing costs, then ease of manufacture improves, but there is a risk of losing original image data during compression
Solution Approach 1:
The patent creates a reference frame copy that is stored in the remote frame buffer along with differential data. This reference frame serves as a backup copy of the original image data, ensuring that even with a reduced buffer size, the complete original information is preserved and can be used to reconstruct images without loss, thereby maintaining data integrity while reducing manufacturing costs
Solution Approach 2:
The patent performs preliminary compression of image data into differential form before transmission and storage. By pre-processing the data to extract only necessary changes and storing both the differential data and reference frame in advance, the system ensures that no original image data is lost while minimizing the buffer size required, thus achieving both ease of manufacture and data reliability
3Device complexity
If lossless compression is applied to reduce frame buffer size, then manufacturing costs are reduced, but the compression algorithm requires additional processing time and computational resources
Solution Approach 1:
The patent applies partial compression by transmitting only differential data (changes between frames) rather than compressing entire images. This partial action approach reduces the compression processing time and computational resources required, while still achieving significant frame buffer size reduction. The reference frame is transmitted once and reused for multiple differential comparisons, minimizing repeated compression operations
Data Source
AI summary
A display device includes a source unit; and a sink unit connected with the source unit via an embedded display port interface for signal transmission between the source and sink units and to enable a panel self refresh (PSR) mode for reducing power consumption; a still image detector that is included in the source unit, and analyzes an input image to detect a still image; a compressor that is included in the source unit and losslessly compresses data of the still image by using a previously stored compression algorithm; and a PSR controller that is included in the source unit, compares a size of the losslessly compressed data with a size of a frame buffer of the sink unit in order to determine whether the data of the still image can be stored in the frame buffer in a losslessly compressed format without loss.