Motionless active depth from defocus system using smart optics for camera autofocus applications

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Date
2016-04-29
Authors
Amin, M. Junaid
Riza, Nabeel A.
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Society of Photo-Optical Instrumentation Engineers (SPIE)
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Abstract
This paper describes a motionless active Depth from Defocus (DFD) system design suited for long working range camera autofocus applications. The design consists of an active illumination module that projects a scene illuminating coherent conditioned optical radiation pattern which maintains its sharpness over multiple axial distances allowing an increased DFD working distance range. The imager module of the system responsible for the actual DFD operation deploys an electronically controlled variable focus lens (ECVFL) as a smart optic to enable a motionless imager design capable of effective DFD operation. An experimental demonstration is conducted in the laboratory which compares the effectiveness of the coherent conditioned radiation module versus a conventional incoherent active light source, and demonstrates the applicability of the presented motionless DFD imager design. The fast response and no-moving-parts features of the DFD imager design are especially suited for camera scenarios where mechanical motion of lenses to achieve autofocus action is challenging, for example, in the tiny camera housings in smartphones and tablets. Applications for the proposed system include autofocus in modern day digital cameras.
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Keywords
Depth from defocus , Computational imaging , Coherent radiation , Cameras Imaging systems , Imaging systems , Projection systems , Distance measurement , Image processing , Optical sensors
Citation
Amin, M. J. and Riza, N. A. (2016) 'Motionless active depth from defocus system using smart optics for camera autofocus applications', Proceedings of SPIE, 9896, Optics, Photonics and Digital Technologies for Imaging Applications IV, 98960N, SPIE Photonics Europe, 2016, Brussels, Belgium, 29 April. doi: 10.1117/12.2227753
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© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.