Determination of Shape and Fall Velocity of Raindrops by lmage Processing

Ken-ichiro MURAMOTO  

IEICE TRANSACTIONS on Information and Systems   Vol.E78-D   No.8   pp.1051-1057
Publication Date: 1995/08/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Image Processing, Computer Graphics and Pattern Recognition
image processing,  raindrop,  shape,  fall velocity,  rainfall rate,  

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A computer-based system for the automatic determination of the physical parameters of rainfall was developed. The measuring device consists of a light source and two TV cameras. Images of raindrops that fell through the slit were observed on a frosted glass plate as shadow images which were photographed simultaneously by two TV cameras with different shutter speeds and analyzed. The data indicated that the shape of raindrops were spheroid in case of small diameter but were slightly deformed into an oblate spheroid in case of larger diameter, and the fall velocity tends to increase with increasing size of raindrops. Rainfall rates calculated from the shape and velocity were compared with those measured directly and found to agree.