Wavelet Coefficient Reordering for Low-Latency Image Encoding
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Solution Overview
Problem
Conventional image compression techniques, such as JPEG and JPEG 2000, face delays in transmitting encoded image data due to the need to finalize header information after completing encoding of an entire frame or field, leading to increased latency between the transmitting and receiving sides.
Innovation Solution
An encoding device and method that perform hierarchical filtering on image data to generate sub-bands of coefficient data, rearrange and entropy encode these data in a predetermined order, and packetize them with headers, allowing for incremental transmission and decoding, thereby reducing delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional image compression techniques (JPEG, JPEG 2000) are used to encode entire frames or fields before transmission, then high compression ratios and image quality are achieved, but significant delay time occurs between transmitting side and receiving side
Solution Approach 1:
The patent divides the image data into multiple blocks and processes each block independently through filtering and encoding. This segmentation allows incremental transmission of encoded data without waiting for complete frame encoding, thereby reducing delay time while maintaining image quality through systematic processing of divided regions
Solution Approach 2:
The patent performs filtering processing on image data before encoding to generate coefficient data in advance. By preprocessing the image data through filtering and organizing coefficient data beforehand, the system enables faster subsequent encoding and transmission, reducing the overall delay between transmitting and receiving sides
2Manufacturing precision
If wavelet transformation coding is used to eliminate block distortion, then image quality is improved, but encoding efficiency and delay time are worsened due to complete frame encoding requirements
Solution Approach 1:
The patent applies wavelet transformation coding to divided blocks rather than complete frames. By segmenting the image into multiple blocks and processing each block independently through wavelet transformation, the system eliminates block distortion within each block while enabling incremental encoding and transmission, thus improving both image quality and encoding efficiency
Solution Approach 2:
The patent performs wavelet transformation on partial blocks rather than waiting for complete frame processing. By applying the transformation to available blocks incrementally and transmitting encoded data as it becomes available, the system achieves good image quality without the excessive delay associated with complete frame encoding
Data Source
AI summary
An encoding device includes a filter unit that performs a filtering processing as to image data, for a line block including image data of a number of lines for generating coefficient data of one line of a sub-band of at least a lowest band component. The filter unit generates a plurality of sub-bands made up of coefficient data broken down by frequency band. The encoding device also includes a storage unit that stores coefficient data generated by the filter unit, for the line block. The encoding device further includes a coefficient rearranging unit that rearranges the coefficient data, for each line block, in an order in which a synthesizing processing, for generating image data by synthesizing the coefficient data of a plurality of sub-bands which have been divided into frequency bands, is to be executed. An encoding unit encodes the coefficient data rearranged by the coefficient rearranging unit.