Computer-generated holograms (CGHs), such as those used in optical testing, are created by etching patterns into an optical substrate. Imperfections in the etching can cause small scale surface roughness that varies across the pattern. The variation in this roughness affects the phase and amplitude of the wavefronts in the various diffraction orders. A simplified model is developed and validate...

It has been more than 36 years since Lohmann and Paris first described computer generated holograms (CGHs) [1] and CGHs have been used to test aspheric optical elements for more than 35 years [2]. Computer generated holograms are now widely used in the testing of aspheric optical elements and it is expected that their use in aspheric testing will greatly increase the next few years as the super...

This review paper deals about the main optical NDT (Non-Destructive Testing) method known as, electronic speckle Interferometry. Optical metrology is a field of physics, which includes theoretical and experimental methods to estimate physical parameters, using the light wavelength as fundamental scale. Most of the modern industries need quick and reliable measurement methods for measuring defor...

Optical plasma diagnostic systems often require a complex optical path involving mirrors, lenses and windows. The use of optical fibres could significantly simplify the design of such a system. Radiation-induced effects, namely induced absorption and luminescence, may compromise the integration of optical fibres in the diagnostic system. However, recent developments of new fused silica glass ty...

James Webb Space Telescope Optical Telescope Element (OTE) is a three mirror anastigmat consisting of a 6.5 m primary mirror (PM), secondary mirror (SM) and a tertiary mirror. The primary mirror is made out of 18 segments. The telescope and instruments will be assembled at Goddard Space Flight Center (GSFC) to make it the Optical Telescope Element-Integrated Science Instrument Module (OTIS). Th...

Despite their promising improvements in performance and power efficiency, the possibilities of reconfigurable computing in multiprocessor environments are still mainly unexplored. This paper presents a new framework for rapid testing of multicores with application-specific reconfigurable accelerators. The design exploration is a multi-step flow that performs automatic generation of fine-grained...

the aim of present study is to investigate the kinematics of tool-workpiece’s relative movement in conventional and ultrasonic-vibration assisted turning (uat). the kinematic analysis of uat shows that the movement of cutting tool edge relative to the workpiece resulted from the cutting speed, feed speed and tool’s vibration affects the lateral machined surface of workepiece and leaves a repeat...

This section contains a review of physical fundamentals and results of practical implementation of methods of nondestructive testing (NDT) and evaluation. It also presents relevant information on magnetic, electrical, eddy current, HF electromagnetic, infrared, optical, acoustic, radiographic, penetrant and other (such as vibration, leakage testing and integrated) methods of NDT and evaluation ...

Problem statement: Instead of using Fiber Bragg Grating (FBG) to develop the coded spectrums, which consist of expensive elements, the grating also are highly sensitive to environmental changes and this will contribute to the increment of capital and operational expenditures (CAPEX and OPEX). Approach: This study presented the development of low-cost 16-ports encoding device for Optical Code Di...

Optical flow can be used to segment a moving object from its background provided the velocity of the object is distinguishable from that of the background, and has expected characteristics. Existing optical flow techniques often detect flow (and thus the object) in the background. To overcome this, we propose a new optical flow technique, which only determines optical flow in regions of motion....