%0 Journal Article
%T Quantitative Schlieren Image-Noise Reduction Using Inverse Process and Multi-Path Integration
%A Ahmad Zaid Nazari
%A Yojiro Ishino
%A Fumiya Ito
%A Harumi Kondo
%A Ryoya Yamada
%A Takanori Motohiro
%A Yu Saiki
%A Yoshiaki Miyazato
%A Shinichiro Nakao
%J Journal of Flow Control, Measurement & Visualization
%P 25-44
%@ 2329-3330
%D 2020
%I Scientific Research Publishing
%R 10.4236/jfcmv.2020.82002
%X This report deals with introducing two new techniques based on a novel concept of complex brightness gradient in quantitative schlieren images, ˇ°inverse processˇ± and ˇ°multi-path integrationˇ± for image-noise reduction. Noise in schlieren images affects the projections (density thickness) images of computerized tomography (CT). One spot noise in the schlieren image appears in a line shape in the density thickness image. Noise effect like an infectious disease spreads from a noisy pixel to the next pixel in the direction of single-path integration. On the one hand, the noise in the schlieren image reduces the quality of the image and quantitative analysis and is undesirable; on the other it is unavoidable. Therefore, the importance of proper noise reduction techniques seems essential and tangible. In the present report, a novel technique ˇ°multi-path integrationˇ± is proposed for noise reduction in projections images of CT. Multi-path integration is required the schlieren brightness gradient in two orthogonal directions. The 20-directional quantitative schlieren optical system presents only images of schlieren brightness in the horizontal gradient and another 20-directional optical system seems necessary to obtain vertical schlieren brightness gradient, simultaneously. Using the ˇ°inverse processˇ±, a new technique enables us to obtain vertical schlieren brightness gradient from horizontal experimental data without the necessity of a new optical system and can be used for obtaining any optional directions of schlieren brightness gradient.
%K Noise Reduction Technique
%K Inverse Process
%K Quantitative Schlieren Optical System
%K Complex Schlieren Brightness
%K Computerized Tomography (CT)
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=100228