Dictionary Compression Using Effective-Bit Matching for Digital Signals

Solution Overview

Problem

Existing information compression methods using dictionaries, such as LZ, struggle to achieve a desired compression ratio for digital signals like audio and image data due to the infrequent occurrence of similar value combinations.

Innovation Solution

The method compares input information with a dictionary using effective bit digits and outputs an index for matching bits, focusing on imbalanced binary distributions to improve compression efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional dictionary-based compression methods (LZ) are used, then the method is simple and widely applicable, but the compression ratio is insufficient for digital signals with infrequent similar value combinations

Engineering Contradiction:

Improveapplicability of compression methodVSAvoidcompression ratio

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent changes the matching parameter from requiring complete value combination matches to matching based on effective bit digits only. This parameter change allows the compression method to work effectively with digital signals where only certain bits carry meaningful information, thereby improving compression ratio while maintaining applicability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the binary data into effective bit digits and insignificant bits, applying different processing rules to each segment. This segmentation allows the compression algorithm to focus on matching only the meaningful portions of the data, increasing the frequency of successful matches and improving overall compression efficiency.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If matching is performed on all bits of input information, then complete accuracy is achieved, but the frequency of finding matching indices decreases

Engineering Contradiction:

Improvematching accuracyVSAvoidfrequency of finding matching indices

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the effective bit digits from the complete binary data for matching purposes, leaving out the insignificant bits. This extraction increases the frequency of finding matching indices by reducing the strictness of the matching criteria, while still maintaining sufficient accuracy for compression purposes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the matching parameter from requiring complete value combination matches to matching based on effective bit digits only. This parameter change allows the compression method to work effectively with digital signals where only certain bits carry meaningful information, thereby improving compression ratio while maintaining applicability.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the dictionary stores complete character strings, then the storage is comprehensive, but the memory usage increases and compression efficiency decreases

Engineering Contradiction:

Improvecompleteness of dictionary storageVSAvoidmemory usage

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts only the effective bit digits from the complete binary data for matching purposes, leaving out the insignificant bits. This extraction increases the frequency of finding matching indices by reducing the strictness of the matching criteria, while still maintaining sufficient accuracy for compression purposes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the binary data into effective bit digits and insignificant bits, applying different processing rules to each segment. This segmentation allows the compression algorithm to focus on matching only the meaningful portions of the data, increasing the frequency of successful matches and improving overall compression efficiency.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS7667630B2Information compression-encoding device, its decoding device, method thereof, program thereof, and recording medium storing the program

Publication Date: 2010.02.23 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

The present invention aims to improve the compression ratio of an encoding method using a dictionary for such as LZ77, LZ78 or LZW for a sample string of an audio signal or an image signal. According to the present invention, the samples are aligned from the MSB side (73), and for an NC-th (NC is the character size, for example, eight bits) character C1(i), the samples are partitioned by starting from the MSB side, and a partitioned portion less than NC is added with dummy bits “0” until the size reaches NC to form a character (74). In this processing, lower bits in the samples can be ignored, mask data M1(i) is created in which digits in the ignorable bit and dummy bits for each C1(i) are set to “0” and effective bits (digits) are set to “1” (75), C1(i) is compared with each character D(j) in a character string for an index j in the dictionary using M1(i) to check whether or not there are matches for effective digits portions in C1(i). If there are matches, C1(i) is considered to match D(j).