2017 Volume 2 Pages 47-52
This paper attempts to give an approach on the already researched areas of unsteady flow field including shockwaves which were measured integrating density gradients by using the BOS (background oriented schlieren) method. Our BOS measurement systems consists of a digital camera, a background of the stripe patterns and a LED flash lamp. Projection data have been obtained by using BOS results which are the pixel displacement distribution data in the background. In regards to our previous study, we have constructed a three-dimensional distribution data from the obtained projection data using the ART (algebraic reconstruction technique) or the PSACT (parallel computing simulated annealing computed tomography) reconstruction technique. However, upon the existing obstacles, the BOS measurement presented some partial defects of measurement data. Related to this fact in the CT artifacts occurred defects of the projection data. Therefore, we need to evaluate the projection data which is used in the CT reconstruction. In this paper, we have discussed about and evaluated the projection data which was obtained from the projection angle with a range of 0 to 180 degrees.
