Use of a speckle reduction technique to improve the reconstruction image quality of CCD-based optical computed tomography scanner

This study proposed a speckle reduction technique (SRT) that employs a rotating diffuser in the parallel beam optical computed tomography (CT). Results showed that the mean and standard deviation of the gray level are 89.79 +/- 4.53 and 89.16 +/- 2.88 for reconstruction images without SRT and with SRT, respectively. The proposed SRT effectively removed ring artifacts. In addition, two image processing techniques, namely, the mean and Wiener filters, were also used to improve the reconstructed images. The image processing technique alone effectively reduced ring artifacts, but some fluctuations were still observed in the line profiles of the reconstructed images. Results proved that the proposed SRT is a simple method that is easily implemented to improve image quality for parallel beam optical CT. The combination of SRT and image filters was suggested to achieve the best image reconstruction quality through the full removal of ring artifacts. (C) 2015 Elsevier B.V. All rights reserved.