Research Of Raindrop Size Distribution Measurement Based On Machine Vision

RSD (Raindrop Size Distribution) contains abundant microphysical character of precipitation, is an important parameter in the aspect of remote sensing attenuation、 artificial influence the weather and water and soil conservation Therefore, many scholars put forward many methods of RSD measurement, the method filter paper is extensively used, because of its easy operation and low cost but the method of diameter measurement is complicated, labor-intensive, long testing cycle, inefficient, subjectivity. So machine vision technology is used in the process of diameter measurement, with its non-contact, high speed, good stability advantage instead of the method of filter paper diameter measurement, which greatly improved the detection efficiency.According to the requirements of the Office of the artificial rainfall in Jilin Province, the measurement research of RSD characteristic parameter is carried out, and the key is overlap particles segmentation. The rain stain left on filter paper is treated by image preprocessing and divided into separate particles and overlap particles. The separate particles can be measured by calculating the stain pixies, but the overlap particles can not. Firstly, Canny edge detection operator is used to extract the outline of the boundaries of overlapping stain, and concave point is got by the method of sum of vertical distance between the point and chord approximating curvature.Secondly according to the relationship between concave points and stain number, Bresenham algorithm for strain-line is used to connect candidate concave points and separated overlapping stain particles. At last, the stain diameter is measured by the relationship of stain diameter, raindrop diameter, and stain pixels, and the concept of particle size distribution is used to calculate the average rainfall intensity.The program and GUI (Graphic User Interface) is accomplished by the software of MATLAB, The experimental results showed that the machine vision technology to replace manual processing of raindrop size splash image to quickly, accurately and efficiently to achieve the statistics of the rainfall raindrop diameter...