I-touch based phase shift reflectometry for shape measurement
Ahmad Zaki Jama Ludin
Date of Issue2014
School of Mechanical and Aerospace Engineering
In most industry, inspection is the key in producing quality products. As demand for quality products has been progressively vital to end-users, it is a must to have a top-notch quality control requirements and this can be done using Non Destructive Testing (NDT). There are many ways to conduct NDT and the common methods are visual, liquid penetrant, magnetic, ultrasonic, eddy current and X-ray. However, the use of non-contact based method, like visual, has been attracting interest in recent development due to their merits. Visual method includes using tools like optical or laser instruments. This visual method, or also known as optical technique, introduces the reconstruction of three-dimensional profile (3D) of the object. This technique has been the focus of recent development. With development of reflective three-dimensional computer-vision method, specular reflective objects can be inspected by NDT. This method is also known as fringe reflection technique where fringe pattern that is displayed will be reflected by the specular reflective object. This has become an effective tool for three-dimensional measurement in specular reflective objects, as it is simple, robust and is appropriate for industrial environment. A technique used to measure the three-dimensional (3D) shape is a non-contact, fast and easy to implement technique. As been said earlier, it uses the principle of a generalized fringe reflection technique. It also employs the random phase-shifting, multi-frequency phase unwrapping and calibration system in order to determine the 3D shape with as much accuracy as possible. Most system that uses this technique is usually catered for huge objects. Therefore, a compact fringe reflection system has been developed. However, there is a need to make the system works and modify it in order to obtain a perfect fringe reflection system. It will be explored and experimented on to find the possible abilities of the compact fringe reflection system.
Final Year Project (FYP)
Nanyang Technological University