Abstract
We developed a telecentric 3D measurement system based on the fringe projection technique to measure phases corresponding to the 3D shape of bumps on a surface. A measurement algorithm based on an area scan camera with a flexibly programmable region of interest (ROI) was applied to reconstruct the 3D model. Only the pixel information within the ROI is stored, which reduces the data volume and processing and accelerates the area scan acquisition. Experiments showed that the fringe projection system provided good linearity between the calibration and optical data with excellent accuracy. A reflectometry sensor was implemented to provide a correction offset to the bump height in a protection layer in a subsequent high-speed inspection.
Highlights
The development of optical 3D shape measurement methods is rapidly gaining importance in the manufacturing industry due to its capability of measuring and reconstructing real 3D moving objects [1,2,3,4]
This paper presents a major effort towards improving the performance of 3D shape measurement systems based on fringe projection and phase shifting
This paper presents a novel designed module that works with an improved frame rate This paper presents a novel designed module that works with an improved frame and is compatible with the hardware system by adjusting the region of interest (ROI)
Summary
The development of optical 3D shape measurement methods is rapidly gaining importance in the manufacturing industry due to its capability of measuring and reconstructing real 3D moving objects [1,2,3,4]. The phase-shifting technique is based on using multiple projections of various stripe patterns to provide continuous phase maps and is the most well-known method for obtaining the absolute phase and corresponding object height. Three-dimensional imaging systems based on the fringe projection technique measure the absolute phase corresponding to the 3D shape of an object surface. A novel measurement algorithm was developed that is based on an area scan camera with a flexibly programmable region of interest (ROI) sensor area containing selectable rows to simultaneously acquire three fringe images with 120◦ phase shifts. A spectroscopic reflection model and Fourier transform (FT) analysis algorithm, which are applicable in the case of a silicon substrate covered by a thick semitransparent PI layer on top of another semitransparent insulating film, were developed to accurately determine the thickness of each transparent film and their contributions to the bump height measurement error. Eliminating the strong reflection effect of the silicon substrate in optical measurements is not easy; spectroscopic reflection model fitting may be the best way to clearly identify the multiple interfaces between the air and silicon substrate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
