Determination of Optimum Values of Control Parameters to Reduce Laser Speckle Noise for Projection Moire´ System

2011 ◽  
Author(s):  
Sungbum Kang ◽  
Jie Gong ◽  
I. Charles Ume
Keyword(s):  
Regression Analysis ◽  
Measurement Error ◽  
Control Parameter ◽  
Noise Control ◽  
Laser Interferometry ◽  
Speckle Noise ◽  
Laser Speckle ◽  
Control Parameters ◽  
Plane Displacement ◽  
Projection Moire

Projection moire´ technique using laser interferometry to generate grating patterns is one of the major techniques for out-of-plane displacement or warpage measurement of electronic packaging devices. Laser speckle is one of the most crucial sources of noise that increase measurement error and decrease repeatability of projection moire´ systems. The aim of this work is to reduce the laser speckle noise by optimizing the noise control parameters (laser power, camera exposure and camera gain) to minimize the measurement error and maximize the repeatability of the projection moire´ system. Taguchi’s design experimental method is used to formulate the experimental layout, to investigate the effect of the each control parameter on the measurement error and repeatability, and to determine the best possible parameter levels. Regression analysis is employed to precisely find the optimum values of the each control parameter. The validation test shows that the approach using Taguchi method and regression analysis is well established to optimize the noise control parameters of the projection moire´ system.

scholarly journals Sub-Diffraction Visible Imaging Using Macroscopic Fourier Ptychography and Regularization by Denoising

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3154 ◽  
Author(s):  
Zhixin Li ◽  
Desheng Wen ◽  
Zongxi Song ◽  
Gang Liu ◽  
Weikang Zhang ◽  
...  
Keyword(s):  
Phase Retrieval ◽  
State Of The Art ◽  
Imaging Technique ◽  
Speckle Noise ◽  
Laser Speckle ◽  
Coherent Imaging ◽  
Quantitative Metrics ◽  
Visible Imaging ◽  
Flow Algorithm ◽  
Diffraction Imaging

Imaging past the diffraction limit is of significance to an optical system. Fourier ptychography (FP) is a novel coherent imaging technique that can achieve this goal and it is widely used in microscopic imaging. Most phase retrieval algorithms for FP reconstruction are based on Gaussian measurements which cannot extend straightforwardly to long range, sub-diffraction imaging setup because of laser speckle noise corruption. In this work, a new FP reconstruction framework is proposed for macroscopic visible imaging. When compared with existing research, the reweighted amplitude flow algorithm is adopted for better signal modeling, and the Regularization by Denoising (RED) scheme is introduced to reduce the effects of speckle. Experiments demonstrate that the proposed method can obtain state-of-the-art recovered results on both visual and quantitative metrics without increasing computation cost, and it is flexible for real imaging applications.

A simple projection moiré system to measure displacements of aircraft structures

2007 ◽  
Vol 42 (6) ◽  
pp. 477-495 ◽  
Author(s):  
U Galietti ◽  
K Genovese ◽  
L Lamberti ◽  
D Posa
Keyword(s):  
Analytical Model ◽  
Large Scale ◽  
Industrial Applications ◽  
Processing Method ◽  
Simple Analytical Model ◽  
Aerodynamic Loads ◽  
Out Of Plane ◽  
Plane Displacement ◽  
Good Agreement ◽  
Projection Moire

This work presents a simple projection moiré system (PMS) to measure displacements of large-scale aeronautical components. The system includes standard optics, uses a standard fringe-processing method, and relies on a simple analytical model to recover topographic information. An extensive calibration campaign, based on design of experiments, is conducted in order to find the best analytical model for retrieving the out-of-plane displacement field from the moiré pattern and to find the optimal combination of parameters involved in the measurement system. In order to check the suitability of the present PMS device for practical industrial applications, distortions induced by aerodynamic loads on a landing-light glazing of an Airbus A340 are measured. Experimental results are in good agreement with other measurements carried out independently.

Control of Laser Speckle Noise Using Liquid Crystals

2011 ◽  
Vol 50 (9S2) ◽  
pp. 09NE14 ◽  
Author(s):  
Hirokazu Furue ◽  
Atsuo Terashima ◽  
Masato Shirao ◽  
Yukio Koizumi ◽  
Masatoshi Ono
Keyword(s):  
Liquid Crystals ◽  
Speckle Noise ◽  
Laser Speckle

Measurement error in regression analysis

1980 ◽  
Vol 9 (7) ◽  
pp. 717-723
Author(s):  
Amitava Mitra ◽  
Khursheed Alam
Keyword(s):  
Regression Analysis ◽  
Measurement Error

scholarly journals A colony count model for the control of drinking water distribution systems

2005 ◽  
Vol 9 (2) ◽  
pp. 189-205
Author(s):  
A. Kerneis ◽  
A. Déguin ◽  
M. Feinberg
Keyword(s):  
Organic Matter ◽  
Process Control ◽  
Residence Time ◽  
Distribution Systems ◽  
Control Parameter ◽  
Control Parameters ◽  
Supply Water ◽  
Biodegradable Organic Matter

The purpose of this study is to select a process control parameter for monitoring microbial regrowth in a network and to develop a more accurate and relevant quality control of supply water. Two parameters were examined as potential process control parameters: the water residence time in the network and the concentration of biodegradable organic matter. Residence time calculations were carried out and validated by tracer studies in a branched network and then in a simply looped network. The measurement of the natural dissolved organic carbon (DOC) consumption in the network was preferred to the determination of any in vitro biodegradation. The measurement of consumption requires the determination of DOC in treated water and in supply water. It is simpler and less expensive than other biodegradable organic matter determinations. A model for colony counts as a function of the residence time was developed in order to demonstrate that this parameter can be used for process controlling. This model was very well adjusted to data collected in a network in winter, spring and summer. This process control parameter was then used in order to locate and estimate the quantity of water whose colony counts exceed the European directive guide level. Accurate correlation measurements between colony counts and DOC consumed in the network were carried out in three distinct systems. No significant correlations were measured. For these three networks, biodegradable organic matter measurements based on DOC determinations were demonstrated to be unreliable process control parameters for monitoring bacterial regrowth.

Warpage Measurement Using Projection Moire´ System and Two Automatic Image Segmentation Algorithms

2007 ◽  
Author(s):  
Wei Tan ◽  
I. Charles Ume
Keyword(s):  
Image Segmentation ◽  
Electronic Packages ◽  
Printed Wiring Board ◽  
Segmentation Algorithms ◽  
Out Of Plane ◽  
Cte Mismatch ◽  
Image Models ◽  
Wiring Board ◽  
Plane Displacement ◽  
Projection Moire

Out-of-plane displacement (warpage) has been a major reliability concern for board-level electronic packaging. Printed wiring board (PWB) and component warpage results from CTE mismatch among the materials that make up the PWB assembly (PWBA). Warpage occurring during surface-mount assembly reflow processes and normal operations may lead to serious reliability problems. In this paper, a projection moire´ warpage measurement system and two types of automatic image segmentation algorithms were presented. In order to use the projection moire´ technique to separately determine the warpage of a PWB and assembled electronic packages in a PWBA, two image segmentation algorithms based on mask image models and active contour models (snakes) were developed. They were used to detect package locations in a PWBA displacement image generated by the projection moire´ system. The performances of the mask image and snake approaches based on their resolutions, processing rates, and measurement efficiencies were evaluated in this research. Real-time composite Hermite surface models were constructed to estimate the PWB warpage values underneath the electronic packages. The above automatic image segmentation algorithms were integrated with the projection moire´ system to accurately evaluate the warpage of PWBs and assembled chip packages individually.

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