A NOVEL METHOD BASED ON THE OTSU THRESHOLD FOR INSTANTANEOUS ELIMINATION OF LIGHT REFLECTION IN PIV IMAGES

2021 ◽  
Author(s):  
Rodrigo de Lima Amaral ◽  
Vítor Augusto Andreghetto Bortolin ◽  
Bernardo Luiz Harry Diniz Lemos ◽  
Marcelo Mazzetto ◽  
Idágene A Cestari ◽  
...  
Keyword(s):  
Moving Objects ◽  
Interrogation Window ◽  
Plane Motion ◽  
New Method ◽  
Centrifugal Impeller ◽  
Light Reflection ◽  
Ventricular Assist ◽  
Scattering Of Light ◽  
Tracer Particles ◽  
Out Of Plane

Abstract The base of particle image velocimetry (PIV) is the maximization of the correlation between the distribution of particle images in an interrogation window or a volume separated by an instant of time. In real images, the unwanted reflection of light on fixed walls or moving objects can directly interfere with the correlation, deteriorating the PIV quality. In this work, a new method for automatically generating instantaneous masks based on the Otsu threshold for instantaneous elimination of light reflection in PIV images is proposed. This method separates the saturated image caused by the unwanted scattering of light from the tracer particles images through the Otsu threshold combined with the Gauss filter and Wiener adaptive local filter. This new method, called Otsu-Gauss-Wiener (OGW), was first tested using synthetic PIV images. In these tests, the authors analyzed the reflection caused by an object regarding different sizes, shapes, and intensities to evaluate the performance of the proposed method. Later, the OGW method was tested in PIV experimental cases with real adversities, for example, scattering of light on a fixed wall in a channel with periodic hills (Case B – 4th PIV Challenge), strong reflection in a centrifugal impeller (Case C – 1st PIV Challenge) and light scattering caused by an out-of-plane motion of the diaphragm of a pulsatile pediatric ventricular assist device. The results shown that the method can remove the reflections by static and moving objects using an automatic mask generated for each instantaneous image.

Out-of-Plane Motion Effects in Microscopic Particle Image Velocimetry

2003 ◽  
Vol 125 (5) ◽  
pp. 895-901 ◽  
Author(s):  
Michael G. Olsen ◽  
Chris J. Bourdon
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Laser Sheet ◽  
Plane Motion ◽  
Entire Volume ◽  
Measurement Volume ◽  
Microscopic Particle ◽  
Image Velocimetry ◽  
Out Of Plane ◽  
Signal Peak

In microscopic particle image velocimetry (microPIV) experiments, the entire volume of a flowfield is illuminated, resulting in all of the particles in the field of view contributing to the image. Unlike in light-sheet PIV, where the depth of the measurement volume is simply the thickness of the laser sheet, in microPIV, the measurement volume depth is a function of the image forming optics of the microscope. In a flowfield with out-of-plane motion, the measurement volume (called the depth of correlation) is also a function of the magnitude of the out-of-plane motion within the measurement volume. Equations are presented describing the depth of correlation and its dependence on out-of-plane motion. The consequences of this dependence and suggestions for limiting its significance are also presented. Another result of the out-of-plane motion is that the height of the PIV signal peak in the correlation plane will decrease. Because the height of the noise peaks will not be affected by the out-of-plane motion, this could lead to erroneous velocity measurements. An equation is introduced that describes the effect of the out-of-plane motion on the signal peak height, and its implications are discussed. Finally, the derived analytical equations are compared to results calculated using synthetic PIV images, and the agreement between the two is seen to be excellent.

Vibrational potentials of the low frequency out‐of‐plane motion in the ground and excited singlet electronic states of 9,10‐dihydrophenanthrene

1992 ◽  
Vol 96 (10) ◽  
pp. 7229-7236 ◽  
Author(s):  
Marek Z. Zgierski ◽  
Francesco Zerbetto ◽  
Young‐Dong Shin ◽  
Edward C. Lim
Keyword(s):  
Low Frequency ◽  
Electronic States ◽  
Plane Motion ◽  
Excited Singlet ◽  
Out Of Plane

A pOH Jump Driven by N═N Out-of-Plane Motion in the Photoisomerization of Water-Solvated Triazabutadiene

2017 ◽  
Vol 121 (26) ◽  
pp. 4939-4947
Author(s):  
Hongmei Xiao ◽  
Lishuang Ma ◽  
Weihai Fang ◽  
Xuebo Chen
Keyword(s):  
Plane Motion ◽  
Out Of Plane

Electrostatically-Driven-Leverage Actuator as an Engine for Out-of-plane Motion

2001 ◽  
pp. 740-743 ◽  
Author(s):  
Hung-Yi Lin ◽  
Hsin-Hwa Hu ◽  
Weileun Fang ◽  
Ruey-Shing Huang
Keyword(s):  
Plane Motion ◽  
Out Of Plane

Out-of-Plane Comb-Drive Lever Actuator

2000 ◽  
Author(s):  
Hung-Yi Lin ◽  
Weileun Fang
Keyword(s):  
Electrostatic Force ◽  
Plane Motion ◽  
Comb Drive ◽  
Out Of Plane ◽  
Gap Closing

Abstract In the present study, an out-of-plane motion actuator driven by the electrostatic force is designed and fabricated. The electrostatic force generated by the gap closing electrodes and the comb electrodes will be studied. Moreover, a lever motion transmitting mechanism is proposed to modulate the motion of the actuators. Although the space between the driving electrodes is limited, the lever motion transmitting mechanism could enlarge the traveling distance. The applications of the out-of-plane motion actuator are remarkably increased due to the assistant of the transmitting mechanism.

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