Progressive JPEG Decoder Using Modified Scans
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Solution Overview
Problem
The increasing resolution of progressive JPEG images requires longer decoding times, which is inefficient for embedded devices with baseline JPEG decoder support, as adding a progressive JPEG decoder incurs significant costs and necessitates new hardware development.
Innovation Solution
A progressive JPEG decoder is developed that utilizes a processing unit to generate modified progressive scans, coupled with a baseline JPEG decoder including a Huffman decoder, inverse quantization unit, and inverse transform unit, allowing for decoding using existing baseline JPEG decoder hardware by adding zero and sign maps to enhance decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a progressive JPEG decoder is added to support progressive JPEG image decoding, then the ability to decode progressive JPEG images is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent makes the existing baseline JPEG decoder hardware perform multiple functions by processing modified progressive scan data. The same decoder circuitry that normally processes baseline JPEG scans is adapted to process progressive JPEG scans through data transformation, eliminating the need for separate progressive JPEG decoding hardware.
Solution Approach 2:
The patent introduces a processing unit that acts as an intermediary between the progressive JPEG data stream and the baseline JPEG decoder. This processing unit transforms progressive scan data into a format compatible with baseline JPEG decoding, allowing the existing decoder to handle progressive images without direct hardware modification.
2Adaptability or versatility
If software decoding is used for progressive JPEG images, then progressive JPEG images can be decoded, but the decoding time increases significantly
Solution Approach 1:
The patent replaces software-based progressive JPEG decoding with a hardware-based solution. By using the existing hardware JPEG decoder with modified input data, the system achieves faster decoding speeds compared to software implementation, while maintaining progressive JPEG compatibility.
3Manufacturing precision
If image resolution increases, then image quality improves, but the decoding time increases proportionately
Solution Approach 1:
The patent performs preliminary processing of the progressive scan data to convert it into baseline JPEG-compatible format before decoding. This pre-processing step organizes the data in a way that allows the hardware decoder to process high-resolution images more efficiently, reducing the proportional increase in decoding time that would otherwise occur with higher resolutions.
Data Source
AI summary
A progressive JPEG (joint photographic experts group) decoder is disclosed. The progressive JPEG decoder includes a processing unit that receives a plurality of progressive scans and generates a plurality of modified progressive scans (MPSs). A baseline JPEG decoder, coupled to the processing unit, includes a Huffman decoder, an inverse quantization unit and an inverse transform unit. The Huffman decoder receives a current MPS and generates a set of transform coefficients corresponding to the current MPS. The processing unit adds a set of transform coefficients corresponding to a previous MPS to the set of transform coefficients corresponding to the current MPS, and the processing unit generates quantization indices. The inverse quantization unit estimates inverse quantization values based on the quantization indices. The inverse transform unit estimates inverse transform decoded values based on the estimated inverse quantization values and generates a set of pixels corresponding to the current MPS.