Dynamics range enhancement in digital fringe projection technique

2015 ◽  
Vol 39 ◽  
pp. 243-251 ◽  
Author(s):  
Gelareh Babaie ◽  
Mehrdad Abolbashari ◽  
Faramarz Farahi
2020 ◽  
Vol 20 (3) ◽  
pp. 139-144
Author(s):  
Cheng-Yang Liu ◽  
Tzu-Ping Yen ◽  
Chien-Wen Chen

AbstractThe three-dimensional (3-D) micro-scale surface imaging system based on the digital fringe projection technique for the assessments of microfiber and metric screw is presented in this paper. The proposed system comprises a digital light processing (DLP) projector, a set of optical lenses, a microscope, and a charge coupled device (CCD). The digital seven-step fringe patterns from the DLP projector pass through a set of optical lenses before being focused on the target surface. A set of optical lenses is designed for adjustment and size coupling of fringe patterns. A high-resolution CCD camera is employed to picture these distorted fringe patterns. The wrapped phase map is calculated by seven-step phase-shifting calculation from these distorted fringe patterns. The unwrapping calculation with quality guided path is introduced to compute the absolute phase values. The dimensional calibration methods are used to acquire the transformation between real 3-D shape and the absolute phase value. The capability of complex surface measurement for our system is demonstrated by using ISO standard screw M1.6. The experimental results for microfiber with 3 μm diameter indicate that the spatial and vertical resolutions can reach about 3 μm in our system. The proposed system provides a fast digital imaging system to examine the surface features with high-resolution for automatic optical inspection industry.


2014 ◽  
Vol 487 ◽  
pp. 572-575
Author(s):  
Zaliman Sauli ◽  
Vithyacharan Retnasamy ◽  
Nor Shakirina Nadzri ◽  
Christopher John Veriven

Digital fringe projection technique using phase shifting method has been studied extensively for generatingthree dimensional (3D) surface information. The aim of this paper is to develop a simple automated optical inspection (AOI) system using fringe projection technique to capture image of an object. A three step phase shifting is used to generate the saw tooth image to retrieve the information of the pixel coordinate and surface dimension. The calibration of the camera and projector is observed to contribute a great significant on the measurement accuracy. The developed system is capable to measure the object surface dimension and perform the 3D reconstruction with high speed and good precision.


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