Event-Based Weak Oil Impurity Detection

Machine vision-based methods are usually applied to detect impurities in transparent liquids like water or alcohols. Oils have higher viscosity and lower light transmittance, so traditional vision detection methods do not work well. A weak oil impurity detection algorithm was proposed using event stream data. In this method, the binary image of the oil was firstly captured using an event camera. To reduce the noise interference from the event camera, image filtering and morphological operations were applied. Then, image algebra operations were used to remove the oil container’s bottom pattern. Finally, impurity detection was performed through the YOLOv5 network. Three common edible oils serve as the experimental samples. Small flying insects, raw material fragments, metal fragments, hair strands, and tin beads of various sizes are selected as the weak impurities. Experiments were performed on a dataset containing 3000 sample images. To the best of our knowledge, existing algorithms can detect impurities with the minimum size of 0.4mm, and most of the experimental samples are transparent liquids. The proposed method can be applied to detect impurities in water and oils, and the detectable impurity size limit is 0.2mm.