Optimization of digital holographic setup by a fuzzy logic prediction system

基于模糊逻辑预测系统的数字全息方案优化

Expert Systems with Applications, Volume 56, 1 September 2016, Pages 177-185

Gulhan Ustabas Kaya, Okan Erkaymaz, Zehra Sarac

Abstract:In this study, the optimization of the digital holography setup is achieved by a using fuzzy logic prediction system. In fact, when this optimization process is experimentally performed, some parameters are changed in the setup. These parameters affect directly the obtained image quality after a reconstruction process, which is determined by normalized root mean square. The aim of this study is to achieve the optimization of digital holographic setup by using both experimental and fuzzy logic prediction systems. Furthermore, the required time during the experimental optimization can be lowered by using a numerical method like the fuzzy logic prediction system. Here, the experimental optimization results and the optimization results obtained by the fuzzy logic prediction system are compared. It is offered that the designed experimental system can be optimized by using an artificial intelligent tool. The applied fuzzy logic prediction model is used the first time for optimization of hologram recording setup. As a result, it is reached a conclusion that the optimization of digital holographic setup can be numerically performed by the fuzzy logic prediction system. Moreover, while digital holographic setup is experimentally designed, the required time for optimization is reduced, as well.

On the mode I fracture analysis of cracked Brazilian disc using a digital image correlation method

基于数字图像关联方法的裂纹巴西圆盘模式I断裂分析

Optics and Lasers in Engineering, Volume 78, March 2016, Pages 99-105

Mohammad Abshirini, Nasser Soltani, Parisa Marashizadeh

Abstract:Mode I of fracture of centrally cracked Brazilian disc was investigated experimentally using a digital image correlation (DIC) method. Experiments were performed on PMMA polymers subjected to diametric-compression load. The displacement fields were determined by a correlation between the reference and the deformed images captured before and during loading. The stress intensity factors were calculated by displacement fields using William׳s equation and the least square algorithm. The parameters involved in the accuracy of SIF calculation such as number of terms in William׳s equation and the region of analysis around the crack were discussed. The DIC results were compared with the numerical results available in literature and a very good agreement between them was observed. By extending the tests up to the critical state, mode I fracture toughness was determined by analyzing the image of specimen captured at the moment before fracture. The results showed that the digital image correlation was a reliable technique for the calculation of the fracture toughness of brittle materials.

New measurement possibilities of deformation anomalies and complete stress field distributions by portable digital-holographic gauge camera

用便携式数字全息测量摄像仪进行变形异常及完整应力场分布测量的可能性探索

Procedia Structural Integrity, Volume 2, 2016, Pages 2307-2314

Ferenc Gyímesi, András Szigethy, Venczel Borbély, Rafael T. Kiss

Abstract:Holographic interferometric deformation measurements have more than half century behind them. However, up to last decade they have been restricted mostly to laboratory measurements. The turning-point was the advent of three technical novelties: small solid state lasers, high resolution digital image sensors and fast enough computers. This started the long awaited transfer process from the closed laboratory rooms toward the real industrial environment. The Laser-FALCONEYE (L-FE) digital-holographic gauge camera is one of the forerunners in this transfer process which is still far from end. The dozen examples of applications to be outlined here intend to support this process further more. The examples can be divided in two main areas: deformation distribution measurements and stress distribution measurements based on stress-relief deformation measurement at diagnostic blind-hole drilling. The measured materials are mainly metals - but plastics, glasses, ceramics and rocks, too, have been measured with success.

A new wavelet-based reconstruction algorithm for twin image removal in digital in-line holography

一种新的基于小波的重构算法在数字同轴全息孪生像消除中的应用

Optics and Lasers in Engineering, Volume 82, July 2016, Pages 159-172

Jamel Hattay, Samir Belaid, Taoufik Aguili, Denis Lebrun

Abstract:Two original methods are proposed here for digital in-line hologram processing. Firstly, we propose an entropy-based method to retrieve the focus plane which is very useful for digital hologram reconstruction. Secondly, we introduce a new approach to remove the so-called twin images reconstructed by holograms. This is achieved owing to the Blind Source Separation (BSS) technique. The proposed method is made up of two steps: an Adaptive Quincunx Lifting Scheme (AQLS) and a statistical unmixing algorithm. The AQLS tool is based on wavelet packet transform, whose role is to maximize the sparseness of the input holograms. The unmixing algorithm uses the Independent Component Analysis (ICA) tool. Experimental results confirm the ability of convolutive blind source separation to discard the unwanted twin image from in-line digital holograms.