Dynamic Capacitance Compensation Memory Interface for LCD
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Solution Overview
Problem
Conventional Dynamic Capacitance Compensation (DCC) methods for Liquid Crystal Displays (LCDs) face challenges in minimizing chip size and reducing picture-quality deterioration, particularly due to the need for large memory storage and inefficient color sampling compression techniques that cause color changes and low compression efficiency.
Innovation Solution
An apparatus and method that includes a first line buffer for storing pixel values, an encoder for transforming and quantizing these values into bit streams, a memory for storing the bit streams, a decoder for decoding and outputting the bit streams, a second line buffer for temporarily storing decoded pixel values, and a compensation pixel value detector that calculates pixel differences between current and previous frames, allowing for efficient DCC without the need for extensive memory storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel values of previous frames are stored without compression in memory, then DCC can be performed accurately, but memory size and chip area increase significantly
Solution Approach 1:
The patent creates a compressed copy of previous frame pixel values using color sampling compression (YCbCr transformation and down-sampling). This compressed copy is stored in memory and then decoded during DCC processing, allowing accurate pixel value comparison while reducing the memory space required to store the compressed data compared to storing full-resolution uncompressed data.
Solution Approach 2:
The patent changes the parameter representation by transforming pixel values from RGB color space to YCbCr color space and applying down-sampling. This parameter transformation reduces the data volume while preserving essential image information needed for DCC calculations, thereby reducing memory requirements without significantly impacting DCC accuracy.
2Quantity of substance
If color sampling compression is used to reduce memory loads, then compression efficiency improves, but color changes and picture quality deterioration occur
Solution Approach 1:
The patent applies different compression strategies to different color components. The luminance component (Y) is compressed through down-sampling, while chrominance components (Cb, Cr) are handled through selective processing. This local quality approach allows aggressive compression where it matters least for memory reduction while preserving critical color information where needed for picture quality.
Solution Approach 2:
The patent incorporates feedback mechanisms where the decoded compressed pixel values are compared with current frame pixel values during the DCC process. This feedback loop allows the system to adjust compression parameters and decoding processes to maintain picture quality while achieving memory reduction, ensuring that the compressed data remains suitable for accurate DCC calculations.
Data Source
AI summary
There are provided an apparatus and method for performing dynamic capacitance compensation (DCC) in a liquid crystal display (LCD). The DCC apparatus includes: a first line buffer reading and temporarily storing pixel values of an image for each line; an encoder transforming and quantizing the pixel values stored for each line for each block and generating bit streams; a memory storing the generated bit streams; a decoder decoding the bit streams stored in the memory for the each block and outputting the decoded bit streams; a second line buffer reading and temporarily storing the decoded pixel values for the each block; and a compensation pixel value detector detecting a compensation pixel value for each pixel, from pixel value differences between pixel values of a current frame stored in the first line buffer and pixel values of a previous frame stored in the second line buffer. Therefore, it is possible to reduce the number of pins of a memory interface by reducing the number of memory device for storing pixel values of image data, required for performing DCC of a LCD, resulting in minimizing a chip size, and to enhance compression efficiency without visual deterioration in images.