Three-dimensional CT data processing for inspection

Wenjian Wang; Lan Han; Xiaogu Wu; William G. Wee

doi:10.1117/12.339877

28 January 1999 Three-dimensional CT data processing for inspection

Wenjian Wang, Lan Han, Xiaogu Wu, William G. Wee

Proceedings Volume 3586, Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware III; (1999) https://doi.org/10.1117/12.339877
Event: Nondestructive Evaluation Techniques for Aging Infrastructures and Manufacturing, 1999, Newport Beach, CA, United States

Abstract

For workpiece inspection applications such as internal edge measurement verifications, 3D data processing for detecting the internal and external surface of the object is required. Rather than detecting edge points on each slice of CT image and stacking them up, we detect the 3D surface points directly from a sequence of CT images. Using this strategy, surfaces whose normals are vertical to the slices can be detected. We present a set of 3D edge detection methods, facet-model-based, morphology-based, and wavelet-based for evaluation. The facet-model-based surface detection method uses facet model to estimate the local 3D directional derivatives and location of the zeros of the second 3D directional derivatives along the direction of gradient. Subvoxel accuracy can be achieved using this method. The morphology-based method performs a 3D dilation-erosion residue operation first. Then the zero crossings of the residue result images are detected, and the surface points are extracted. The wavelet-based method performs a 3D wavelet transform on the CT images, and the local maxima of the gradient are detected and marked as surface points. The performance of these surface detectors are compared. Finally, as an illustration, we apply the facet-model-based method on a set of engine blade CT images with resolution of 5 mil by 5 mil and the measurements of thickness of wall are taken. A linear regression model is used to correct the systematic error. The results are very close to the direct optical measurements of cut-up sections of the blade with a maximum error of 3 mil.

Citation Download Citation

Wenjian Wang, Lan Han, Xiaogu Wu, and William G. Wee "Three-dimensional CT data processing for inspection", Proc. SPIE 3586, Nondestructive Evaluation of Aging Aircraft, Airports, and Aerospace Hardware III, (28 January 1999); https://doi.org/10.1117/12.339877

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available