Continuous focusing of moving objects using image defocus

Gopal Surya; Murali Subbarao

doi:10.1117/12.188739

3 October 1994 Continuous focusing of moving objects using image defocus

Gopal Surya, Murali Subbarao

Proceedings Volume 2347, Machine Vision Applications, Architectures, and Systems Integration III; (1994) https://doi.org/10.1117/12.188739
Event: Photonics for Industrial Applications, 1994, Boston, MA, United States

Abstract

A Depth-from-Defocus method named STM was presented recently for stationary objects. Here we extend STM for continuous focusing of moving objects. The method is named Continuous STM or CSTM. Focusing is done by moving the lens with respect to the image detector. Two variations of CSTM - CSTM1 and CSTM2 - are presented. CSTM1 is a straight forward extension of STM described in. It involves calibration of the camera for a number (about 6 in our implementation) of discrete lens positions. In CSTM2 the camera is calibrated only for one lens position. The calibration data corresponding to other lens positions are obtained by transforming the data of the one lens position for which the camera is calibrated. In the experimental results presented here, the focusing error in lens position was about 2.25% for CSTM1 and about 3% for CSTM2.

Citation Download Citation

Gopal Surya and Murali Subbarao "Continuous focusing of moving objects using image defocus", Proc. SPIE 2347, Machine Vision Applications, Architectures, and Systems Integration III, (3 October 1994); https://doi.org/10.1117/12.188739

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