scholarly journals A Simulation Analysis of an Extension of One-Dimensional Speckle Correlation Method for Detection of General In-Plane Translation

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ivana Hamarová ◽  
Petr Šmíd ◽  
Pavel Horváth ◽  
Miroslav Hrabovský
Keyword(s):  
Simulation Analysis ◽  
Speckle Pattern ◽  
Correlation Method ◽  
Object Plane ◽  
Speckle Field ◽  
Geometrical Arrangement ◽  
One Dimensional ◽  
Speckle Correlation ◽  
Speckle Patterns

The purpose of the study is to show a proposal of an extension of a one-dimensional speckle correlation method, which is primarily intended for determination of one-dimensional object's translation, for detection of general in-plane object's translation. In that view, a numerical simulation of a displacement of the speckle field as a consequence of general in-plane object's translation is presented. The translation componentsaxandayrepresenting the projections of a vectoraof the object's displacement onto bothx- andy-axes in the object plane(x,y)are evaluated separately by means of the extended one-dimensional speckle correlation method. Moreover, one can perform a distinct optimization of the method by reduction of intensity values representing detected speckle patterns. The theoretical relations between the translation componentsaxandayof the object and the displacement of the speckle pattern for selected geometrical arrangement are mentioned and used for the testifying of the proposed method's rightness.

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.

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

ATOMIC FORCE MICROSCOPE (AFM)-BASED DIGITAL IMAGE SPECKLE CORRELATION (DiSC) TECHNIQUE FOR THE MEASUREMENT OF DEFORMATION IN NANOSCALE

2004 ◽  
Vol 03 (06) ◽  
pp. 789-795
Author(s):  
X. Q. SHI ◽  
J. P. PICKERING ◽  
C. K. WONG
Keyword(s):  
Digital Image ◽  
Experimental Measurement ◽  
Plane Deformation ◽  
Measurement Techniques ◽  
Correlation Method ◽  
Electronic Packages ◽  
Wafer Level ◽  
Speckle Correlation ◽  
Atomic Force

Experimental measurement techniques for the determination of stress levels and distributions will be one of most important keys for the optimization of the design of the next generation electronic packages, e.g., nano-wafer-level packages. However, current experimental photo-mechanics techniques are often found to be insufficiently sensitive but also lacking in sufficient resolution to determine stress distributions of nanoscale electronic packages. In this study, the digital image speckle correlation method was combined with the atomic force microscopy (AFM) to develop a new experimental measurement technique, so-called nanodigital image speckle correlation (Nano-DiSC), for the determination of deformation on the nanometer scale. With the developed theoretical model, computational algorithms and nanospeckle pattern preparation method, the Nano-DiSC methodology was found to be able to measure the in-plane deformation on the sub-10 nm scale.

Diagnosis of MEMS Packages Using Speckle Correlation Method: An Application in Pressure Sensor Packaging

2000 ◽  
Author(s):  
Xiantao Yan
Keyword(s):  
Pressure Sensor ◽  
Glass Bead ◽  
Pressure Sensors ◽  
Correlation Method ◽  
Ccd Camera ◽  
Fuel Vapor ◽  
Thermal Shock Test ◽  
Sensor Applications ◽  
Speckle Correlation ◽  
Speckle Patterns

Abstract Cracked glass beads embedded in the plastic housing material of fuel vapor pressure sensors have been observed after a few hundreds of cycles of thermal shock test. In order to diagnose the root cause of the cracked glass bead, the speckle correlation method is used to in-situ measure the thermal deformation field on the surface of the glass bead. Measurements are taken at 130°C, 26°C and −40°C. The speckle patterns at different temperature are recorded digitally by a CCD camera with a resolution of 1024×1024 pixels. Every two sequential speckle patterns are compared to yield the displacement field of the sample. Then the strain fields are calculated by a finite deformation formulation. Results reveal that the material made of the glass bead is highly non-uniform, and there exists a highly tensile strain zone on the surface of the glass bead. This is correlated with the location of cracking in the bead. Moreover, there is a sliding zone along the boundary of the glass bead, which may result in leakage. As a replacement for glass bead, a metal bead embedded in housing material is examined. Experimental results show that strain level in the metal bead is lower than that in the glass bead, which will reduce disturbance on the sensor part. In addition to that, there are no potential cracking and leakage problems in the pressure sensor applications. Therefore, the metal bead is recommended for future pressure sensor applications.

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