document: Three-dimensional particle image tracking for dilute particle-liquid flows in a pipe A three-dimensional -LRB- 3D -RRB- particle image tracking technique was used to study the coarse spherical particle-liquid flows in a pipe . The flow images from both the front view and the normal side view , which was reflected into the front view by a mirror , were recorded with a CCD camera and digitized by a PC with an image grabber card . An image processing program was developed to enhance and segment the flow image , and then to identify the particles . Over 90 % of all the particles can be identified and located from the partially overlapped particle images using the circular Hough transform . Then the 3D position of each detected particle was determined by matching its front view image to its side view image . The particle velocity was then obtained by pairing its images in successive video fields . The measurements for the spherical expanded polystyrene particle-oil flows show that the particles , like the spherical bubbles in laminar bubbly flows , tend to conglomerate near the pipe wall and to line up to form the particle clusters . As liquid velocity decreases , the particle clusters disperse and more particles are distributed in the pipe centre region
doc_bio_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O B I O O O O O O O O O O O
extractive_keyphrases: ccd camera 3d position particle clusters hough transform
abstractive_keyphrases: three-dimensional particle image tracking dilute particle-liquid flows two-phase flow pipe flow stereo-imaging technique phase distribution spherical expanded polystyrene particle spherical bubble wiener filter image segmentation region growing technique image recognition image matching