scholarly journals OpenOpticalFlow_PIV: An Open Source Program Integrating Optical Flow Method with Cross-Correlation Method for Particle Image Velocimetry

2021 ◽  
Vol 9 ◽  
Author(s):  
Tianshu Liu ◽  
David M. Salazar
Keyword(s):  
Particle Image Velocimetry ◽  
Optical Flow ◽  
Open Source ◽  
Cross Correlation ◽  
Particle Image ◽  
Correlation Method ◽  
Flow Method ◽  
Optical Flow Method ◽  
Source Program ◽  
Image Velocimetry

Hybrid Optical-Flow-Cross-Correlation Method for Particle Image Velocimetry

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Tianshu Liu ◽  
David M. Salazar ◽  
Hassan Fagehi ◽  
Hassan Ghazwani ◽  
Javier Montefort ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Optical Flow ◽  
Hybrid Method ◽  
Cross Correlation ◽  
Particle Image ◽  
Intensity Change ◽  
Flow Method ◽  
Optical Flow Method ◽  
Air Jet ◽  
Image Velocimetry

Abstract A hybrid method for particle image velocimetry (PIV) is developed to overcome the limitations of the optical flow method applied to PIV images with large displacements. The main elements of the hybrid method include a cross-correlation scheme for initial estimation, a shifting scheme for generating a shifted image, and an optical flow scheme for obtaining a refined high-resolution velocity field. In addition, a preprocessing scheme is used for correcting the illumination intensity change. The accuracy of the hybrid method is evaluated through simulations in a parametric space in comparison with the typical correlation methods and optical flow method. Further quantitative comparisons are made in PIV measurements in a circular air jet.

scholarly journals The Optical Flow Method Research of Particle Image Velocimetry

2015 ◽  
Vol 99 ◽  
pp. 918-924 ◽  
Author(s):  
Wang Hongwei ◽  
Huang Zhan ◽  
Gong Jian ◽  
Xiong Hongliang
Keyword(s):  
Particle Image Velocimetry ◽  
Optical Flow ◽  
Particle Image ◽  
Flow Method ◽  
Optical Flow Method ◽  
Image Velocimetry

Multi-Cross-Correlation Method in Particle Image Velocimetry

2011 ◽  
Vol 27 (3) ◽  
pp. 365-377
Author(s):  
T.-W. Hsu ◽  
C.-Y. Shin ◽  
S.-H. Ou ◽  
Y.-T. Li
Keyword(s):  
Particle Image Velocimetry ◽  
Cross Correlation ◽  
Particle Image ◽  
Processing System ◽  
Correlation Method ◽  
Seeding Density ◽  
Image Velocimetry ◽  
Accuracy Of Measurements ◽  
Out Of Plane ◽  
Particle Images

ABSTRACTA multi-cross-correlation method (MCCM) was developed in a particle image velocimetry (PIV) auto-processing system to reduce spurious vectors and improve accuracy of measurements. This technique is an improvement based on conventional cross-correlation method (CCM). Four typical neighboring interrogation windows were specified to be overlapped and calculated by MCCM. A high cross-correlation value is obtained in which many particle images match up with their corresponding spatially shifted partners, and small cross-correlation peaks due to interference of noises during experiments are reduced. Several parameters such as out-of-plane motions, particle size, and seeding density are considered for checking both MCCM and conventional PIV algorithms. The examination gives authenticity to the merits of MCCM for avoiding particles loss or mistaken velocity vectors.

Optical-Flow Algorithm for Near-Wake Analysis of Axisymmetric Blunt-Based Body at Low-Speed Conditions

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
The Hung Tran ◽  
Lin Chen
Keyword(s):  
Optical Flow ◽  
Cross Correlation ◽  
Transient Flow ◽  
Wake Flow ◽  
Near Wake ◽  
Dominant Type ◽  
Low Speed ◽  
Flow Method ◽  
Optical Flow Method ◽  
Flow Algorithm

Abstract In this study, ability of an optical-flow algorithm in extracting wake structure of axisymmetric model was investigated. The initial data for optical-flow processing were obtained in low-speed conditions by particle image velocimetry method. The Reynolds number based on the model diameter was around ReD = 1.97 × 104 in this study. Both the time-averaged and transient flow characteristics of near-wake flow were illustrated and examined by the optical-flow analysis method proposed. The processing results of optical-flow method showed good agreement with conventional cross-correlation methods. The ability of optical-flow method to extract flow fields was, thereby, confirmed for blunt-based flow at low-speed conditions. This study showed that the antisymmetric flow behavior of the near wake is the dominant type at low-speed conditions. Differing to traditional methods and cross-correlation results, the optical-flow results showed a frequency at around StD = 0.015 of the near wake for the first time, which is connected to vortex shedding behavior of the wake flow.

scholarly journals Particle image velocimetry with optical flow

1998 ◽  
Vol 25 (3) ◽  
pp. 177-189 ◽  
Author(s):  
G. M. Quénot ◽  
J. Pakleza ◽  
T. A. Kowalewski
Keyword(s):  
Particle Image Velocimetry ◽  
Optical Flow ◽  
Particle Image ◽  
Image Velocimetry
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