A study of video-based droplet detection

The disdrometer system is a new imaged-based technique developed to measure the shape of droplets. This system contains three components: a CCD camera for capturing video images, a backlight source for illuminating drops and enhancing images, and a control unit for data acquisition and function control. In our preliminary study, we replaced raindrops with a free fall of droplets from a homemade liquid dropper. Subsequently, the high-speed CCD camera captured images of the falling droplets. We controlled the exposure time to 1 ms, which resulted in the falling droplets blurring in the assessment. To detect the droplet contours precisely, we used Pascal´s theorem to determine the best-fit ellipse shape. We concluded that the proposed image-based disdrometer system provides a promising approach to measure and monitor the falling droplets. Moreover, this instrument can be less expensive as it only requires basic maintenance for long-lasting daily use.