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Proceedings Paper

3D reconstruction based on wavelet pyramid image fusion algorithm for digital microscope
Author(s): Lei Zhang; Peng Liu; Yuling Liu; Feihong Yu
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Paper Abstract

Optical microscopy is an important technique in petrological and biological. However, because of the limited focus depth of a traditional optical microscope, 3D objects can't be observed with all its information in one scene. The commonly used method to solve this problem is to use a digital microscope to collect a sequence of multi-focus images with a constant change of the focal length and then get the final sharp image by fusing the images. Wavelet pyramid algorithm is one of the commonly used fusion algorithms and has a good performance. In this paper, a novel 3D reconstruction algorithm is presented based on the wavelet pyramid image fusion algorithm. First, a sequence of multi-focus images is collected with a digital microscope and then the images are fused with the wavelet pyramid fusion algorithm. After that, the deviation between the fused image and each of the original multi-focus images are calculated pixel by pixel. For convenience, the absolute value of the deviation is calculated. The smaller the deviation, the closer the corresponding pixel to the focal plane and vice versa. Thus a 3D deviation matrix is obtained. For each pixel position (x, y), the z index of the smallest deviation value in the third direction of the deviation matrix is considered the pixel's height index. A complete height index map is obtained by selecting the indices of these smallest deviation values. In order to eliminate the noise effect, a median filter is applied to the height index map. The height index map times the height factor (the unit step length along the optical axis when collecting the multi-focus images) is the object's actual height map. Finally, the surface of the 3D object is reconstructed with the object's height map. In order to test the reconstruction algorithm, a dedicated high resolution Complementary Metal Oxide Semiconductor (CMOS) digital microscope is designed and fabricated to collect the multi-focus images. Experimental results show that the proposed algorithm produces a nice looking surface of a 3D object.

Paper Details

Date Published: 24 November 2009
PDF: 8 pages
Proc. SPIE 7513, 2009 International Conference on Optical Instruments and Technology: Optoelectronic Imaging and Process Technology, 751312 (24 November 2009); doi: 10.1117/12.837397
Show Author Affiliations
Lei Zhang, Zhejiang Univ. (China)
Peng Liu, Zhejiang Univ. (China)
Yuling Liu, Zhejiang Univ. (China)
Feihong Yu, Zhejiang Univ. (China)

Published in SPIE Proceedings Vol. 7513:
2009 International Conference on Optical Instruments and Technology: Optoelectronic Imaging and Process Technology
Toru Yoshizawa; Ping Wei; Jesse Zheng, Editor(s)

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