Image Encode Controller Chroma Adjustment for Quantization Error
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Solution Overview
Problem
Conventional image encoders do not consider quantization errors during the encoding process, leading to a deterioration in the quality of decoded images, particularly in terms of hue and saturation.
Innovation Solution
An image encode controller is introduced, comprising a chroma component adjuster, difference generator, quantizer, inverse-quantizer, and variable codeword length encoder, which adjusts chroma components based on quantization coefficients to minimize quantization errors in hue and saturation, thereby improving the quality of decoded images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the quantization coefficient is increased to reduce encoding complexity, then the encoding process becomes simpler, but the quantization error increases and the quality of decoded image deteriorates
Solution Approach 1:
The patent applies different quantization strategies to different chroma components. Specifically, it adjusts the quantization coefficient for the second chroma component based on the first chroma component's characteristics. This local differentiation allows the system to maintain higher image quality in critical regions while keeping overall encoding complexity manageable.
Solution Approach 2:
The patent implements a feedback mechanism where the encoder calculates quantization errors for chroma components and uses this information to adjust subsequent encoding parameters. The encoder modifies the quantization coefficient for the second chroma component based on the actual quantization error of the first chroma component, creating a closed-loop system that continuously optimizes image quality.
2Ease of operation
If conventional encoding methods are used without considering quantization error, then the encoding process is simpler, but the hue and saturation quality of decoded images deteriorates
Solution Approach 1:
The patent performs preliminary calculations of quantization errors for chroma components during the encoding process. By pre-calculating these errors and using them to adjust encoding parameters before final encoding, the system maintains encoding simplicity while significantly improving hue and saturation accuracy in the decoded output.
Solution Approach 2:
The patent dynamically changes encoding parameters based on quantization error characteristics. Specifically, it adjusts the quantization coefficient for the second chroma component based on the first chroma component's quantization error. This parameter adaptation allows the system to maintain simple encoding operations while achieving superior hue and saturation precision.
3Productivity
If the quantization coefficient is increased to reduce computational load, then the processing speed increases, but the quantization error increases and image quality deteriorates
Solution Approach 1:
The patent applies different quantization strategies to different chroma components based on their specific characteristics. By locally optimizing the quantization coefficient for each chroma component, the system achieves a balance between processing speed and image quality, avoiding the need to uniformly increase quantization coefficients across all components.
Solution Approach 2:
The patent implements feedback where quantization errors are calculated and used to adjust subsequent encoding operations. This feedback mechanism allows the system to maintain higher processing speeds by dynamically optimizing quantization coefficients based on actual error characteristics, rather than using fixed high quantization coefficients that would uniformly reduce computational load at the cost of quality.
Data Source
AI summary
According to one embodiment, an image encode controller includes a chroma component adjuster, a difference generator, a quantizer, an inverse-quantizer, and a variable codeword length encoder. The chroma component adjuster adjusts an original color component in accordance with a quantization coefficient to generate an adjusted chroma component. The difference generator generates a difference pixel component. The quantizer quantizes an output of the difference generator based on the quantization coefficient. The inverse-quantizer inversely quantizes an output of the quantizer based on the quantization coefficient. The variable codeword length encoder performs variable codeword length encoding with respect to an output of the quantizer to generate encoded data. The difference generator generates the difference pixel component based on a pixel component corresponding to an i-th pixel (where i denotes natural number), the adjusted chroma component, and an output of the inverse-quantizer corresponding to the (i−1)th pixel.