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Uncertainty of digital image correlation under video compression and DSP optimization.
Applied Optics
|April 3, 2024
Summary
High Efficiency Video Coding (HEVC/H.265) compression impacts digital image correlation (DIC) accuracy. Optimized digital speckle patterns (DSPs) with 8-pixel speckle sizes achieve high compression ratios with minimal error.
Area of Science:
- Optical techniques
- Image processing
- Materials science
Background:
- High spatial resolution video storage and transmission pose challenges for image-based optical techniques.
- Digital image correlation (DIC) is sensitive to image quality, making video compression a potential source of uncertainty.
Purpose of the Study:
- To assess the uncertainty of digital image correlation (DIC) when applied to videos compressed using High Efficiency Video Coding (HEVC/H.265).
- To investigate the impact of HEVC/H.265 compression on the accuracy and stability of DIC measurements.
- To re-evaluate and optimize digital speckle patterns (DSPs) for DIC under video compression.
Main Methods:
- Evaluation criteria for DIC accuracy under compression were established.
- H.265 video compression stability was studied using varying quantization parameters (QPs) and compression ratios (CRs).
- Deformation uncertainty was analyzed under uniform translation and non-uniform sinusoidal deformation.
- Optimized DSPs with different speckle sizes and randomness were compressed and evaluated.
Main Results:
- The study provides a criterion for evaluating DIC accuracy affected by compression.
- H.265 compression stability was analyzed across different QPs and CRs.
- Deformation uncertainty was quantified under various loading conditions.
- Re-optimized DSPs, particularly those with 8-pixel speckle sizes, demonstrated feasibility under H.265 compression, achieving high CRs with acceptable error margins.
Conclusions:
- HEVC/H.265 video compression introduces uncertainty into DIC measurements.
- Optimized DSPs are crucial for maintaining DIC accuracy under compressed video conditions.
- Feasible high compression ratios for DIC videos are achievable with carefully selected DSPs, validated on a defective bending beam specimen.
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