9 October 1995 Phase-lead reconstruction of a photoelastic tactile sensor
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In this paper, a novel tactile photoelastic transducer for normal forces is presented. When a normal input force profile is applied to the tranduction medium, stress is generated in the photoelastic layer making it birefringent. Consequently, circularly-polarized input light becomes elliptically polarized at the output due to the introduction of a phase-lead distribution. If a circular-reflection polaridoscope is used, the output light-intensity is a circular function of the total phase-lead distribution. The first part of the paper describes the forward analysis of the transducer using finite-element analysis to determine the stress distribution in the transducer. Then, the phase-lead distribution is determined using the theory of photoelasticity. The second part of the paper describes a technique for the recovery of the phase-lead distribution from the ideal noise-free light-intensity distribution. Also, a verification method is proposed to determine whether a recovered phase-lead distribution is the correct one or not. In the third part of the paper, we consider the nonideal situation, where the light-intensity distribution is no longer noise-free. Quantization errors added to the detected light-intensity distribution are also considered. Recovering the phase-lead distribution under noisy conditions constitutes an ill-posed problem. An algorithm that accurately and effectively determines the phase-lead distribution from a noisy light-intensity distribution is presented. The inverse-tactile problem is solved using an optimization function.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ricardo E. Saad, Ricardo E. Saad, A. Bonen, A. Bonen, K. C. Smith, K. C. Smith, B. Benhabib, B. Benhabib, } "Phase-lead reconstruction of a photoelastic tactile sensor", Proc. SPIE 2570, Experimental and Numerical Methods for Solving Ill-Posed Inverse Problems: Medical and Nonmedical Applications, (9 October 1995); doi: 10.1117/12.224182; https://doi.org/10.1117/12.224182

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