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Optical Engineering

Shape from focus using principal component analysis in discrete wavelet transform
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Paper Abstract

We introduce a new approach for 3-D shape recovery based on discrete wavelet transform (DWT) and principal component analysis (PCA). A small 3-D neighborhood is considered to incorporate the effect of pixels from previous as well as next frames. The intensity values of the pixels in the neighborhood are then arranged into a vector. DWT is applied on each vector to decompose it into approximation and wavelet coefficients. PCA is then applied on modified energies of wavelet components. The first feature in the eigenspace, as it contains maximum variation, is employed to compute the depth. The performance of the proposed approach is tested and is compared with existing methods by using synthetic and real image sequences. The evaluation is gauged on the basis of unimodality and monotonicity of the focus curve. Resolution, accuracy, root mean square error (RMSE), and correlation metrics have been applied to evaluate the performance. Experimental results and comparative analysis demonstrate the effectiveness of the proposed method.

Paper Details

Date Published: 1 May 2009
PDF: 9 pages
Opt. Eng. 48(5) 057203 doi: 10.1117/1.3130232
Published in: Optical Engineering Volume 48, Issue 5
Show Author Affiliations
Muhammad Tariq Mahmood, Gwangju Institute of Science and Technology (Korea, Republic of)
Seong-O Shim, Gwangju Institute of Science and Technology (Korea, Republic of)
Tae-Sun Choi, Gwangju Institute of Science and Technology (Korea, Republic of)

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