Moving Image Coding With Cross-File Tampering Detection
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Solution Overview
Problem
Existing moving image coding technologies are incompatible with compression-coded moving image streams divided into files, making it difficult to detect tampering in such streams.
Innovation Solution
A moving image coding apparatus and method that generates and multiplexes time-continuity information, position information, and inspection information with the coded bitstream, allowing for the detection of tampering by comparing these elements across frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If moving image compression technology embeds code signal of preceding frame to detect tampering, then tampering detection capability is improved, but compatibility with file-divided compression coded streams deteriorates
Solution Approach 1:
The patent divides the moving image stream into multiple file segments (first file, second file, etc.) while maintaining tampering detection capability across segment boundaries. Each file contains inspection information that can independently verify tampering within that file, enabling the system to work with file-divided compression coded streams.
Solution Approach 2:
The patent introduces position information and inspection information as intermediary elements that bridge the gap between compression coding and tampering detection. These intermediaries are embedded in the coded bitstream and enable verification without requiring access to original uncompressed frames or preceding frame code signals.
2Measurement precision
If inspection information is generated from coded information at specific positions, then detection precision is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary actions by embedding position information and inspection information during the coding process itself. The position information generation unit and inspection information generation unit operate during coding to pre-calculate and embed verification data, so that tampering detection can be performed later without complex real-time analysis.
Solution Approach 2:
The patent creates simplified copies of verification data (inspection information) that are embedded in the bitstream. Instead of requiring complex reconstruction of original frames for verification, the system uses these copied inspection information values that can be directly compared to detect tampering.
Data Source
AI summary
A moving image coding apparatus adapted to code moving images including time-continuous frames is provided. A moving image coding unit outputs a coded bitstream in which the moving images are coded. A position information generation unit generates position information in a frame, based on time-continuity information indicating time continuity of the frames. A coded information acquisition unit acquires coded information on the moving images, based on the position information. An inspection information generation unit generates inspection information from the coded information. A multiplexing unit multiplexes the bitstream and the inspection information.