Arithmetic Code Amount Estimation Using Context-Based Lookup Tables
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Solution Overview
Problem
Conventional methods for estimating code amounts after arithmetic coding in image data processing are inefficient, leading to difficulties in real-time processing and precision, especially with large data amounts.
Innovation Solution
A code amount estimating device that calculates estimated code amounts using symbol occurrence probability information, probability interval ranges, and context indices, allowing for high-speed and precise estimation by referencing tables for symbol strings and updating probability intervals and occurrence probabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If arithmetic coding is performed on binary data with large data amount, then compression rate is improved, but real-time processing becomes difficult and code amount measurement cannot be performed in real time
Solution Approach 1:
The patent pre-calculates and stores code amount information for various binary symbol strings in a table during the design phase. This preliminary action allows the system to quickly retrieve pre-computed code amounts during real-time processing without performing complex arithmetic coding calculations, thus resolving the contradiction between achieving high compression rates and maintaining real-time processing capability.
2Productivity
If provisional coding is performed without performing arithmetic coding for code amount estimation, then processing speed is improved, but estimation precision deteriorates because the estimation method differs from actual arithmetic coding
Solution Approach 1:
The patent creates a simplified copy of the arithmetic coding process by pre-calculating code amounts based on the actual arithmetic coding algorithm and storing these results in a table. During estimation, the system retrieves values from this table rather than performing full arithmetic coding. This copying approach maintains estimation precision by preserving the mathematical relationships of the original algorithm while achieving high processing speed through table lookup.
3Measurement precision
If code amount information tables are created for all possible binary symbol strings, then estimation precision is improved, but data storage requirements increase significantly
Solution Approach 1:
The patent extracts only the essential code amount information needed for estimation from the complete set of possible binary symbol strings and stores these extracted values in a compact table. By taking out only the necessary information rather than storing data for all theoretically possible strings, the system achieves sufficient estimation precision while keeping storage requirements manageable.
Data Source
AI summary
To provide a code amount estimating device which can perform, at high speed and with high precision, estimation of code amount obtained after arithmetic coding. The code amount estimating device includes a context index calculation unit which calculates a context index of a binary symbol included in binary data, and an estimate code amount calculation unit which calculates an estimate code amount for the binary data based on symbol occurrence probability information stored in association with the calculated context index and on a held probability interval range. The estimate code amount calculation unit estimates the code amount for the binary data according to code amount information indicating an association between (i) a combination of a binary symbol string including one or more binary symbols, symbol occurrence probability information, and a probability interval range and (ii) an estimate code amount for the binary symbol string.