Digital holographic camera with extended stochastic illumination for non-destructive inspection of silicon optics

2021 ◽  
Author(s):  
Gaurav Dwivedi ◽  
Lavlesh Pensia ◽  
Sanjit K Debnath ◽  
Raj Kumar
Keyword(s):  
Random Phase ◽  
Research Work ◽  
Numerical Control ◽  
Non Destructive Testing ◽  
Cnc Machine ◽  
Destructive Testing ◽  
Full Field ◽  
Specular Surface ◽  
Silicon Optics ◽  
Non Destructive

Abstract In present work, we propose a compact digital holographic camera with extended stochastic illumination for full-field non-destructive inspection of silicon optics fabricated in computerized numerical control (CNC) machine. The developed technique overcomes the limitation of digital holography imparted by definite size of active area of the recording sensor to image a specular surface. The original aspect of this research work is to develop a system that enables reconstruction and testing of specular surface. For this a dual diffuser configuration is incorporated in a compact digital holographic camera developed for non-destructive testing applications. The generation of stochastic illumination beam using the diffusers is explained by simulating propagation of a light beam through random phase function of scattering medium. The stochastic optical field produced by the combination of diffusers in the digital holographic camera makes the camera suitable for non-destructive testing of specular surface of silicon optics. The effect of number of diffusers, and their relative positions on imaging area of specular object is studied for development of an optimized configuration of digital holographic camera. Applicability of proposed scheme is demonstrated through detection of defects in silicon optics using digital holographic interferometry.

scholarly journals A Versatile Illumination System for Real-Time Terahertz Imaging

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3993
Author(s):  
Jean-Baptiste Perraud ◽  
Adrien Chopard ◽  
Jean-Paul Guillet ◽  
Pierre Gellie ◽  
Antoine Vuillot ◽  
...  
Keyword(s):  
Real Time ◽  
Signal To Noise Ratio ◽  
Beam Steering ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Full Field ◽  
Illumination System ◽  
Optimized Distribution ◽  
Non Destructive ◽  
Field Imaging

Terahertz technologies are attracting strong interest from high-end industrial fields, and particularly for non-destructive-testing purposes. Currently lacking compactness, integrability as well as adaptability for those implementations, the development and commercialisation of more efficient sources and detectors progressively ensure the transition toward applicative implementations, especially for real-time full-field imaging. In this work, a flexible illumination system, based on fast beam steering has been developed and characterized. Its primary goal is to suppress interferences induced by the coherence length of certain terahertz sources, spoiling terahertz images. The second goal is to ensure an enhanced signal-to-noise ratio on the detector side by the full use and optimized distribution of the available power. This system provides a homogeneous and adjustable illumination through a simplified setup to guarantee optimum real-time imaging capabilities, tailored to the sample under inspection. Working toward industrial implementations, different illumination process are conveniently assessed as a result of the versatility of this method.

scholarly journals Insights into Acoustically Induced PiezoLuminescence: The Visualization of Ultrasonic Beam Patterns

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 491
Author(s):  
Simon Michels ◽  
Mathias Kersemans ◽  
Guillaume Lajoinie ◽  
Michel Versluis ◽  
Philippe F. Smet
Keyword(s):  
Ultrasonic Transducers ◽  
Non Destructive Testing ◽  
Ultrasonic Beam ◽  
Destructive Testing ◽  
Full Field ◽  
Ultrasound Field ◽  
Non Destructive ◽  
Beam Patterns ◽  
Ultrasonic Investigation

Ultrasonic transducers are used in many fields of application, including medical imaging/treatment, non-destructive testing and material characterization. To assure the quality of the ultrasonic investigation transducers require regular checks for possible deterioration and accurate calibration. Current methods rely on point-by-point scanning of the ultrasound field with a needle hydrophone, which is expensive and time consuming. Recently, we have developed a new concept, in which a fast full-field visualization of the radiation field is achieved through Acoustically induced PiezoLuminescence (APL). Here, we report on an improved ultrasonic beam visualization and provide further insights into the mechanism underlying APL and mechanoluminescence.

scholarly journals Wood Density and Moisture Content Estimation by Drilling Chips Extraction Technique

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1699
Author(s):  
Roberto D. Martínez ◽  
José-Antonio Balmori ◽  
Daniel F. Llana ◽  
Ignacio Bobadilla
Keyword(s):  
Moisture Content ◽  
Research Work ◽  
Estimation Method ◽  
Dry Mass ◽  
Extraction Technique ◽  
Timber Structures ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Wide Range ◽  
Non Destructive

The novelty of this study is the development of an accurate wood moisture content (MC) estimation method based on a relatively brand-new, non-destructive testing technique (drilling chips extraction). The method is especially important in the assessment of existing timber structures, where non-destructive testing (NDT) results are affected by wood MC and should be adjusted to a reference MC, usually 12%. In the assessment of timber structures, it is not possible to determine MC by oven drying method and this should be estimated. Electrical resistance and capacitance are the conventional methods used for MC estimation. This research work aims to present an accurate MC estimation method based on the drilling chips extraction technique. For that, 99 specimens (90 × 65 × 38 mm3) from three softwood and hardwood species covering a wide range of densities (from 355 to 978 kg m−3) were tested after conditioning at five different MCs (5%, 10%, 15%, 20%, 25%). The Wood Extractor device based on the drilling chips extraction technique was used. The mass of the chips collected (drilling residue) from each drill was recorded. The results show that the MC of the chips extracted was statistically significantly different than the MC of the specimen and cannot be directly used as MC determination. However, the chips MC can be used as an estimator of specimen MC with high determination coefficients (R2 from 71% to 86%). As the main result, models to estimate density directly adjusted to a reference 12% MC from the wet and dry mass of chips extracted were developed with an R2 of 98%. In sum, the drilling chips extractor is a dependable and straightforward method to estimate MC and density from only one measurement. Density adjusted to a reference 12% MC can be directly estimated from a single model.

scholarly journals Effect of the Grain Sizes on the Ultrasonic Propagation and Attenuation on Different Types of Steels Microstructure During Non-Destructive Testing

2021 ◽  
Vol 45 (4) ◽  
pp. 329-334
Author(s):  
Irida Markja ◽  
Klodian Dhoska ◽  
Dervish Elezi ◽  
Reza Moezzi ◽  
Michal Petru
Keyword(s):  
Research Work ◽  
Ultrasonic Waves ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Ultrasonic Signals ◽  
Ultrasound Waves ◽  
Different Types ◽  
Shift Frequency ◽  
Ultrasonic Propagation ◽  
Non Destructive

In this paper we have proposed an experimental study of the steel grains sizes effect on the shift frequency of the ultrasonic waves being propagated in steels. Ultrasonic testing has been used in most inspection services for different materials as non-destructive testing. The novelty of our research work has been focused on the investigation of the new method for determining microstructure evolution of metals by using ultrasonic signals in conjunction with changes in grain size and hardness of steels. Furthermore, we have studied the microstructure of steel types S355, S275, Corten B and S275N. The microstructure results of steels have shown the changes that have been undergone from thermal and mechanical processes by using the attenuation of ultrasound waves during non-destructive testing.

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