Determination of optimal number of projections and parametric sensitivity analysis of operators for parallel-ray transmission tomography using hybrid continuous genetic algorithm.

In this work, a hybrid continuous genetic algorithm (HCGA) based methodology has been developed for optimization of number of projections for parallel-ray transmission tomography. The HCGA calculations with filtered back-projection (FBP) utilize 8 bits for both head and lung phantoms. The effect of selection operator through proportionate, truncation, and tournament schemes has been analyzed along with the introduction of a mixed-selection scheme. Image quality has been measured using root-mean-squared error, Euclidean error and peak signal-to-noise ratios. The sensitivity of reconstructed image quality on various mutation operators, namely standard, gradient-, and offset-based schemes, has been analyzed along with the effect of number of projections. The number of projections has resulted in maximization of image quality while minimizing the radiation hazard involved. The results of HCGA have been compared with FBP as a deterministic technique and simulated annealing (SA) as a stochastic technique for IRT approximation. For the 8 × 8 head and lung phantoms, HCGA, SA, FBP, have resulted PSNR values correspondingly as 40.47, 33.92, 8.28 and 26.38, 20.36, 12.98 dB. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 10–21, 2007 [ABSTRACT FROM AUTHOR]