Fixed-Length Image Pixel Encoding for Mobile Bandwidth
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Solution Overview
Problem
Existing image compression methods, such as DPCM, result in lossy compression and variable code word lengths, making it difficult to determine the location of encoded pixels and affecting image quality during transmission, especially in mobile communication devices with limited bandwidth.
Innovation Solution
A method that encodes image pixels with fixed-length code words, indicating the encoding method used, allowing each pixel to be encoded and decoded independently without relying on other pixels, using a combination of differential pulse code modulation (DPCM) for minor changes and pulse code modulation (PCM) for major changes, with the encoding method indicated in the bit string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If DPCM compression is used to reduce data quantity, then the number of bits per pixel is reduced, but the code word length becomes variable making it difficult to determine pixel locations
Solution Approach 1:
The patent changes the parameter of code word length from variable to fixed. By allocating a predetermined fixed number of bits for each code word in the compressed image data, the system ensures that each pixel's encoded position can be precisely determined without ambiguity, while still achieving data compression through selective DPCM application.
2Productivity
If DPCM compression is used to compress image data, then transmission efficiency is improved, but image quality deteriorates due to lossy compression
Solution Approach 1:
The patent introduces dynamic selection of encoding methods based on the characteristics of each pixel or block of pixels. The system adaptively chooses between DPCM (for compression) and PCM (for quality preservation) on a per-pixel or per-block basis, allowing optimal balance between compression efficiency and image quality maintenance without requiring large buffers.
Solution Approach 2:
The patent applies different encoding qualities to different regions or pixels based on their characteristics. High-importance pixels or regions with significant detail are encoded with higher quality (PCM or less aggressive DPCM), while less critical areas use more aggressive compression, achieving overall good image quality with efficient compression.
3Quantity of substance
If compression is applied to reduce data size for mobile communication, then bandwidth usage is reduced, but encoding complexity increases
Solution Approach 1:
The patent divides the image into smaller units (pixels or blocks) and processes each independently with fixed-length code words. This segmentation approach simplifies the encoding process by eliminating the need for complex inter-pixel dependencies and large buffer management, making the compressor suitable for mobile devices with limited processing power.
4Quantity of substance
If variable length code words are used for compression, then data quantity is reduced, but decoding complexity increases and large buffers are required
Solution Approach 1:
The patent changes the code word length parameter from variable to fixed, which fundamentally simplifies the decoding process. With fixed-length code words, the decoder can directly calculate pixel positions without needing to parse variable-length sequences or manage large buffers to track code word boundaries, significantly reducing decoding complexity and memory requirements.
Data Source
AI summary
The invention relates to a method as well as a system, a device, an encoder and a decoder, and a computer software product for image processing by the method. In the invention, the number of bits is limited in the bit string of a pixel to be processed, wherein the pixel is encoded with the limited number of bits. A prediction value corresponding to said pixel is searched for. If it is found, the difference between the pixel and the prediction value is determined, to select the method for encoding the bit string of said pixel. Also, a code word is encoded in the bit string, to indicate the selected encoding method. If the prediction value is missing, the number of bits in said pixel is limited by quantizing. By means of the invention, a fixed number of bits is obtained for all encoded pixels in an image.