Image Coding Apparatus Reducing Quantization Parameter Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for compressing RAW data from image sensors result in large data amounts due to the need for numerous quantization parameters, making it difficult to record at a compact size while maintaining image quality.
Innovation Solution
An image coding apparatus that generates sub-band data, divides it into segments, and uses common quantization parameters for each segment, allowing for flexible quantization control and reduced data amounts by coding the quantization results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If four color channels are generated from RAW data and subjected to three-level octave division through two-dimensional discrete wavelet transform, then each channel is divided into 10 sub-bands enabling fine-grained quantization control, but 40 quantization parameters are required (4 channels × 10 sub-bands), producing a massive data amount for quantization parameters
Solution Approach 1:
The patent merges the quantization parameters of multiple sub-bands into a single common quantization parameter. Specifically, it combines the quantization parameters of four color channels (R, G1, G2, B) into one common parameter that applies to all sub-bands, thereby reducing the total number of quantization parameters from 40 to 1 while maintaining visual image quality.
Solution Approach 2:
The patent creates a universal quantization parameter that serves multiple functions across different color channels and sub-bands. The single common quantization parameter is applied universally to all four color channels and all their respective sub-bands, eliminating the need for channel-specific and sub-band-specific parameters.
2Adaptability or versatility
If a number of quantization parameters equivalent to 4×10×the number of block divisions are required for finer quantization control in predetermined block units, then flexible quantization control is achieved, but the data amount of quantization parameters becomes excessively large
Solution Approach 1:
The patent merges quantization parameters across multiple dimensions (channels and sub-bands) into a single common parameter, achieving a balance between control flexibility and data efficiency. The common quantization parameter is applied to all color channels and sub-bands, providing uniform quantization control without the overhead of numerous individual parameters.
3Reliability
If uncompressed or losslessly-compressed formats are used when recording RAW data, then image quality is preserved, but the size of the recorded RAW data becomes larger than developed compressed image data
Solution Approach 1:
The patent changes the quantization parameters to achieve lossy compression that maintains visual image quality. By using a common quantization parameter applied to all color channels and sub-bands, the patent reduces the data size of RAW data while controlling the compression artifacts to remain imperceptible, thus achieving a balance between compression ratio and perceived image quality.
Data Source
AI summary
An image coding apparatus comprising, a generating unit configured to generate a plurality of pieces of sub-band data from RAW data, a quantization parameter generating unit configured to divide each piece of sub-band data into equal numbers of segments, and generate a first quantization parameter set individually for each segment and common for the plurality of pieces of sub-band data in the same segment, a quantizing unit configured to quantize the segments of the plurality of pieces of sub-band data on the basis of the quantization parameter generated by the quantization parameter generating unit, and a coding unit configured to code a quantization result, obtained from the quantizing, for each piece of sub-band data.