Horn–Schunck optical flow applied to deformation measurement of a birdlike airfoil

Gong, Xiaoliang; Bansmer, Stephan

doi:10.1016/j.cja.2015.07.005

Cited by 13 publications

(4 citation statements)

References 13 publications

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“…These found that the precision of the Optical Flow method was approximately 40 microns, and that this was the same for both the axis in which the movement was in and the axes in which there was no movement. This corresponds to approximately 0.1 pixels, the reported precision for the Optical Flow algorithm (Gong et al 2015).…”

Section: Precision Of Optical Flowmentioning

confidence: 93%

Comprehensive investigation into the stability of Varian and Elekta kV imaging systems during arc delivery

Wright

Hassan

Mukwada

et al. 2020

Biomed. Phys. Eng. Express

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In radiotherapy treatments utilizing accelerator gantry rotation, gantry-mounted kilovoltage (kV) imaging systems have become integral to treatment verification. The accuracy of such verification depends on the stability of the imaging components during gantry rotation. In this study, a simple measurement method and accurate algorithm are introduced for investigation of the kV panel and source movement during gantry rotation. The method is based on images of a ball-bearing phantom combined with a Winston-Lutz phantom, and determines the movements of all the mechanical parameters of the kV imaging system relative to the reference at zero gantry angle. Analysis was performed on different linear accelerators and both gantry rotation directions. The precision of the method was tested and was less than 0.04 mm. This method is suitable to be included in the quality assurance testing of linacs to monitor the kV imaging system performance and provides additional mechanical information that previous tests cannot.

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Section: Precision Of Optical Flowmentioning

confidence: 93%

Comprehensive investigation into the stability of Varian and Elekta kV imaging systems during arc delivery

Wright

Hassan

Mukwada

et al. 2020

Biomed. Phys. Eng. Express

View full text Add to dashboard Cite

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“…Seeing that there are two variables but only one equation, a global smoothness constraint is commonly introduced to solve this equation. This method was first proposed by Horn and Schunck, named Horn &Schunck (HS) optical flow algorithm (Gong & Stephan, ). Supposed that the optical flow varies smoothly at global, the optical flow of image sequence should minimize the following equation:

E = \sum_{x} \sum_{y} {{false(I_{x} u + I_{y} v + I_{t} false)}^{2} + λ^{2} [{false(\nabla u false)}^{2} + {false(\nabla v false)}^{2}]} .

…”

Section: Methodsmentioning

confidence: 99%

Quantitative characterization of the carbon/carbon composites components based on video of polarized light microscope

Song

et al. 2017

Microscopy Res & Technique

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The components of carbon/carbon (C/C) composites have significant influence on the thermal and mechanical properties, so a quantitative characterization of component is necessary to study the microstructure of C/C composites, and further to improve the macroscopic properties of C/C composites. Considering the extinction crosses of the pyrocarbon matrix have significant moving features, the polarized light microscope (PLM) video is used to characterize C/C composites quantitatively because it contains sufficiently dynamic and structure information. Then the optical flow method is introduced to compute the optical flow field between the adjacent frames, and segment the components of C/C composites from PLM image by image processing. Meanwhile the matrix with different textures is re-segmented by the length difference of motion vectors, and then the component fraction of each component and extinction angle of pyrocarbon matrix are calculated directly. Finally, the C/C composites are successfully characterized from three aspects of carbon fiber, pyrocarbon, and pores by a series of image processing operators based on PLM video, and the errors of component fractions are less than 15%.

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“…The latter showed sharper motion boundaries than LK. Based on this analysis, the authors applied the Horn and Schunck algorithm with a course to fine optic flow to measure the static deformation of a birdlike flexible airfoil [17]. Different approaches were proposed to enhance optic flow estimation.…”

Section: Optic Flowmentioning

confidence: 99%

Adaptive Motion Compensated Spatial Temporal Filter of Colonoscopy Video

Azawi

2021

eijs

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Colonoscopy is a popular procedure which is used to detect an abnormality. Early diagnosis can help to heal many patients. The purpose of this paper is removing/reducing some artifacts to improve the visual quality of colonoscopy videos to provide better information for physicians. This work complements a series of work consisting of three previously published papers. In this paper, optic flow is used for motion compensation, where a number of consecutive images are registered to integrate some information to create a new image that has/reveals more information than the original one. Colon images were classified into informative and noninformative images by using a deep neural network. Then, two different strategies were used to treat informative and noninformative images. Informative images were treated by using Lucas Kanade with an adaptive temporal mean/median filter, whereas noninformative images were treated by using Lucas Kanade with a derivative of Gaussian (LKDOG) and adaptive temporal median images. Comparison showed that this work achieved better results than those achieved by the state-of-the-art strategies for the same degraded colon images data set. The new proposed algorithm reduced the error alignment by a factor of about 0.3, with a 100% successful image alignment ratio. In conclusion, this algorithm achieved better results than the state-of-the-art approaches in case of enhancing the informative images as shown in the results section; also, it helped to reveal some information from noninformative images that have very few details/no details.

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Horn–Schunck optical flow applied to deformation measurement of a birdlike airfoil

Cited by 13 publications

References 13 publications

Comprehensive investigation into the stability of Varian and Elekta kV imaging systems during arc delivery

Comprehensive investigation into the stability of Varian and Elekta kV imaging systems during arc delivery

Quantitative characterization of the carbon/carbon composites components based on video of polarized light microscope

Adaptive Motion Compensated Spatial Temporal Filter of Colonoscopy Video

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