PESAC, the Generalized Framework for RANSAC-Based Methods on SIMD Computing Platforms

Abstract

This paper focuses on the computational optimization of RANSAC. We describe the Parallel Efficient Sample Consensus (PESAC) framework that allows efficient utilization of SIMD extensions and provides memory locality due to a special way of storing the input sequence of correspondences and generating a batch of samples per one main loop iteration. It is inspired by the USAC framework and has a block structure capable of implementing most modern RANSAC-based methods. We enhance it with individual blocks of sample and model restrictors that are aimed at the rejection of “bad” samples and model hypothesis before time-consuming model computation and verification blocks. We also provide a detailed description implementing 2D homography estimation problem in PESAC and benchmark the running time on the MIDV-2020 dataset of identity documents. Comparing to naive implementation, we accelerated our framework by 122 times for the document classification task (with a 6% increase in accuracy) and by 18 times for document tracking (with a 46% decrease in tracking failure rate) by using both restrictors and vector processing. This version also outperformed a number of USAC implementations from OpenCV-4.6.0 in runtime and accuracy of estimation (3 times faster, 6% greater accuracy for the classification task, and 2 times faster, 33% lower failure rate for tracking if comparing with USAC_MAGSAC).

Keywords

• Homography estimation
• identity document
• image matching
• localization
• RANSAC
• restrictors