Determination of speckle size and object support from autocorrelation of speckle pattern arrays

1997 ◽  
Author(s):  
David F. Olson ◽  
Robert E. Pierson
Keyword(s):  
Speckle Pattern ◽  
Speckle Size

scholarly journals A New Pattern Quality Assessment Criterion and Defocusing Degree Determination of Laser Speckle Correlation Method

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4728
Author(s):  
Wenxin Hu ◽  
Zhipeng Sheng ◽  
Keyu Yan ◽  
Hong Miao ◽  
Yu Fu
Keyword(s):  
Quality Assessment ◽  
Speckle Pattern ◽  
Correlation Method ◽  
Quality Criterion ◽  
Laser Speckle ◽  
Widespread Application ◽  
Speckle Correlation ◽  
Speckle Patterns ◽  
Speckle Size

The laser speckle correlation method has found widespread application for obtaining information from vibrating objects. However, the resolution and accuracy of the laser speckle correlation method as they relate to the defocusing degree have not been analyzed sufficiently. Furthermore, the possible methods for speckle pattern quality assessment and enhancement have not been studied. In this study, the resolution and accuracy of the laser speckle correlation method are analyzed, and it is found that they are affected by the defocusing degree and speckle pattern quality, respectively. A new speckle pattern quality criterion combining the mean intensity gradient and frequency spectrum was proposed, called CMZ. The quality of the speckle pattern is higher when the CMZ is closer to zero. The proposed criterion was verified by simulated speckle patterns and real speckle patterns with different speckle sizes, densities, and gray contrasts. In the experimental setup stage, a suitable defocusing degree can be selected based on the resolution requirement and optimal speckle size, and other experimental parameters can be determined according to the CMZ criterion. Rotation and vibration experiments verified the effectiveness of the laser speckle correlation method and confirmed the reliability of the experiment preparation based on proposed CMZ criterion.

A new approach for determination of a mean speckle size in simulated speckle pattern

Measurement ◽  
2016 ◽  
Vol 88 ◽  
pp. 271-277 ◽  
Author(s):  
Ivana Hamarová ◽  
Pavel Horváth ◽  
Petr Šmíd ◽  
Miroslav Hrabovský
Keyword(s):  
Speckle Pattern ◽  
New Approach ◽  
Speckle Size

Optimum determination of speckle size to be used in electronic speckle pattern interferometry

1995 ◽  
Vol 34 (1) ◽  
pp. 87 ◽  
Author(s):  
Takeaki Yoshimura ◽  
Minniu Zhou ◽  
Keiji Yamahai ◽  
Zhang Liyan
Keyword(s):  
Speckle Pattern ◽  
Electronic Speckle Pattern Interferometry ◽  
Speckle Size

scholarly journals Methods for Determination of Mean Speckle Size in Simulated Speckle Pattern

2014 ◽  
Vol 14 (3) ◽  
pp. 177-182 ◽  
Author(s):  
I. Hamarová ◽  
P. Šmíd ◽  
P. Horváth ◽  
M. Hrabovský
Keyword(s):  
Gaussian Beam ◽  
Speckle Pattern ◽  
Two Dimensional ◽  
One Dimensional ◽  
Theoretical Predictions ◽  
Speckle Patterns ◽  
Speckle Size ◽  
The Mean ◽  
The One

Abstract This paper deals with computation of mean speckle size in a speckle pattern generated through a numerical simulation of speckle after reflection of a Gaussian beam off a rough object’s surface. Within this simulation various speckle patterns are obtained by means of change in a parameter of the Gaussian beam. The mean speckle size is computed through two approaches using both the two-dimensional and the one-dimensional normalized autocorrelation function in intensity. Additionally, we propose a distinct optimization of the determination of the mean speckle size by reduction of intensity values representing detected speckle patterns. Results of the determination of the mean speckle size are compared with theoretical predictions

scholarly journals A new simulation method for laser speckle imaging to investigate hemodynamics

2019 ◽  
Vol 128 ◽  
pp. 02001
Author(s):  
X Sang ◽  
D Li ◽  
B Chen
Keyword(s):  
Speckle Pattern ◽  
Simulation Method ◽  
Laser Speckle ◽  
Contrast Imaging ◽  
Laser Speckle Imaging ◽  
Speckle Imaging ◽  
Dynamic Speckle ◽  
Speckle Size ◽  
The One

Speckle simulation is a powerful protocol to investigate the properties of speckle and evaluate image processing method. However, only static speckle images can be simulated by available methods without considering time-integrated effect of CCD. A time–integrated dynamic speckle simulation method basedon coherent imaging was developed. Through the new simulation method, the effect of speckle size on LSCI was investigated. The smaller the speckle size is, the higher the spatial resolution become.But the one-dimensional speckle size should exceed two pixels to sample the speckle pattern. The characteristics of existing speckle contrast imaging methods were studied based on spatial statistics, and optimal parameters are given to obtain accurate and less noisy image. In general, the new simulation method for laser speckle imaging is a powerful tool to monitor blood flow in vivo and lay a solid foundation for the study of hemodynamics.

scholarly journals Precise Detection of Wrist Pulse Using Digital Speckle Pattern Interferometry

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Hengfei Zhang ◽  
Sijin Wu ◽  
Weixian Li ◽  
Yonghong Wang ◽  
Mingli Dong ◽  
...  
Keyword(s):  
Speckle Pattern ◽  
Precise Determination ◽  
Diagnostic Methods ◽  
Digital Speckle Pattern Interferometry ◽  
Efficient Detection ◽  
Comprehensive Information ◽  
Arterial Pulsation ◽  
Length Width ◽  
Digital Speckle

Pulse diagnosis is one of the four diagnostic methods of traditional Chinese medicine. However it suffers from the lack of objective and efficient detection method. We propose a noncontact optical method to detect human wrist pulse, aiming at the precise determination of the temporal and spatial distributions of pulse. The method uses the spatial-carrier digital speckle pattern interferometry (DSPI) to measure the micro/nanoscale skin displacement dynamically. Significant improvements in DSPI measurement have been made to allow the DSPI to detect the comprehensive information of the arterial pulsation at locations of Cun, Guan, and Chi. The experimental results prove that the spatiotemporal distributions of pulse can be obtained by the proposed method. The obtained data can be further used to describe most of the pulse parameters such as rate, rhythm, depth, length, width, and contour.

Determination of the Regional Function of the Heart

2002 ◽  
Author(s):  
Evren U. Azeloglu ◽  
Glenn R. Gaudette ◽  
Irvin B. Krukenkamp ◽  
Fu-Pen Chiang
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Speckle Pattern ◽  
Strain Tensor ◽  
Ccd Camera ◽  
Speckle Interferometry ◽  
Left Ventricular ◽  
Stroke Work ◽  
Regional Function

Unlike many other engineering designs, the heart, a pressure vessel, shows variations within its chambers and surface in terms of mechanical function. This necessitates a whole field technique with high spatial resolution. Computer aided speckle interferometry (CASI), a nondestructive examination technique, is herein developed for this purpose. A speckle pattern was created on the surface of isolated rabbit hearts. Images of the beating hearts werc acquired with a charge-couple device (CCD) camera for one second at a rate of 50 frames per second. CASI was used to determine the 2-D displacement vectors over regions of approximately 4 × 6 mm. Regional area stroke work (the integral of the left ventricular pressure with respect to area), the first invariant of the 2-D strain tensor, and the principle strains were used to determine the regional function. After occluding the blood supply to a region of the heart, significant changes were detected in all the previously mentioned parameters. Commonly used techniques cannot determine 2-D strain and lack the high spatial resolution of CASI. Determination of the 2-D strain can provide useful data on the functionality of the heart.

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