In this project, four samples with different light absorption properties were photographed and detected. The experimental results showed that the outline and colour of the droplets could be clearly observed on the sample pictures with the naked eye, proving the excellent imaging performance of the system. Meanwhile, the Python code was used to detect the image, and the minimum diameter of the circular droplet was 1.25μm, and the minimum area of the irregularshaped droplet was 0.13μm², which proved that the system could detect the quantity and size of micron and submicron particles, as well as the distinguishment of complex-colour samples. Finally, with the validation method of spot drawing-printing-detection, it was calculated that the diameter detection error of the system is -15%, and the area detection error is -25%, both of which were within the acceptable range, which proved the system could detect particles with high accuracy.