Large Displacement Detection Using Improved Lucas–Kanade Optical Flow

Abstract

Displacement is critical when it comes to the evaluation of civil structures. Large displacement can be dangerous. There are many methods that can be used to monitor structural displacements, but every method has its benefits and limitations. Lucas–Kanade (LK) optical flow is recognized as a superior computer vision displacement tracking method, but it only applies to small displacement monitoring. An upgraded LK optical flow method is developed in this study and used to detect large displacement motions. One motion controlled by a multiple purpose testing system (MTS) and a free-falling experiment were designed to verify the developed method. The results provided by the upgraded LK optical flow method showed 97 percent accuracy when compared with the movement of the MTS piston. In order to capture the free-falling large displacement, the pyramid and warp optical flow methods are included in the upgraded LK optical flow method and compared with the results of template matching. The warping algorithm with the second derivative Sobel operator provides accurate displacements with 96% average accuracy.

Gas–Liquid Two-Phase Flow Measurement Based on Optical Flow Method with Machine Learning Optimization Model

“…This method has been commonly applied for analysis and recording without computing every pixel in the video, focusing solely on the bubble features within the pipeline. The pyramid optical flow method addresses the challenge of high-speed motion in video frames when the flow rate is large, while the L-K optical flow method is more suitable for fitting the optical flow at lower speeds [28,29].…”

Phase-Based Optical Flow Method with Optimized Parameter Settings for Enhancing Displacement Measurement Adaptability

“…Cheng et al [1] proposed a method utilizing unmanned aerial vehicles (UAVs) and Digital Image Correlation (DIC) technology for measuring bridge vibrations. Al-Qudah et al [2] proposed an improved Lucas-Kanade (LK) optical flow method for detecting large displacement motions in structures. Dong et al [3] proposed an improved feature matching strategy, where manually crafted descriptors are replaced with learned descriptors from the visual geometry group of Oxford University, aiming to achieve higher precision in structural displacement measurement.…”

Spatio-Trajectorial Optical Flow for Higher-Order Deformation Analysis in Solid Experimental Mechanics

“…and strain rate [2], or acceleration [3], from standard and complex motion patterns gains importance in the field of experimental mechanics. In particular, the robustness of evaluation methods to extract those fields from experimental data also under difficult conditions becomes important in this context [4][5][6]. These issues represent the main goal of the methods and investigations proposed in this paper.…”