IMAGE-PROCESSING SYSTEM TO ANALYZE DROPLET DISTRIBUTIONS IN SPRAYS

An image processing system that automatically analyzes the size distributions in fuel spray video images was developed. Images are generated by using pulsed laser light to freeze droplet motion in the spray sample volume under study. This coherent illumination source produces images that contain droplet diffraction patterns representing the droplet's degree of focus. Thousands of images are recorded per sample volume to get an ensemble average of the distribution at that spray location. After image acquisition the recorded video frames are replayed and analyzed under computer control. The analysis is performed by extracting feature data describing droplet diffraction patterns in the iamges. This allows the system to select droplets from image anomalies and measure only those droplets considered in focus. The system was designed to analyze sprays from a variety of environments. Currently these are an ambient spray chamber, a high pressure, high temperature spray facility, and a running engine.