Share Email Print

Proceedings Paper

An edge-from-focus approach to 3D inspection and metrology
Author(s): Fuqin Deng; Jia Chen; Jianyang Liu; Zhijun Zhang; Jiangwen Deng; Kenneth S. M. Fung; Edmund Y. Lam
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

We propose an edge-based depth-from-focus technique for high-precision non-contact industrial inspection and metrology applications. In our system, an objective lens with a large numerical aperture is chosen to resolve the edge details of the measured object. By motorizing this imaging system, we capture the high-resolution edges within every narrow depth of field. We can therefore extend the measured range and keep a high resolution at the same time. Yet, on the surfaces with a large depth variation, a significant amount of data around each measured point are out of focus within the captured images. Then, it is difficult to extract the valuable information from these out-of-focus data due to the depth-variant blur. Moreover, these data impede the extraction of continuous contours for the measurement objects in high-level machine vision applications. The proposed approach however makes use of the out-of-focus data to synthesize a depth-invariant smoothed image, and then robustly locates the positions of high contrast edges based on non-maximum suppression and hysteresis thresholding. Furthermore, by focus analysis of both the in-focus and the out-of-focus data, we reconstruct the high-precision 3D edges for metrology applications.

Paper Details

Date Published: 27 February 2015
PDF: 8 pages
Proc. SPIE 9405, Image Processing: Machine Vision Applications VIII, 94050E (27 February 2015); doi: 10.1117/12.2074757
Show Author Affiliations
Fuqin Deng, ASM Pacific Technology Ltd. (Hong Kong, China)
Jia Chen, Harbin Institute of Technology (China)
Jianyang Liu, Southwest Jiaotong Univ. (China)
Zhijun Zhang, ASM Pacific Technology Ltd. (Hong Kong, China)
Jiangwen Deng, ASM Pacific Technology Ltd. (Hong Kong, China)
Kenneth S. M. Fung, ASM Pacific Technology Ltd. (Hong Kong, China)
Edmund Y. Lam, The Univ. of Hong Kong (Hong Kong, China)

Published in SPIE Proceedings Vol. 9405:
Image Processing: Machine Vision Applications VIII
Edmund Y. Lam; Kurt S. Niel, Editor(s)

© SPIE. Terms of Use
Back to Top
Sign in to read the full article
Create a free SPIE account to get access to
premium articles and original research
Forgot your username?