Measurement algorithm of notch length of plastic parts based on video

A method for measuring the notch length of plastic parts without stopping the machine in real-time industrial environment is proposed, which can be used to measure the notch length on the assembly line. A camera is used for capturing the live images of plastic images being moving straightly. Firstly, invalid frames, clear and blurred keyframes are preprocessed respectively. Then, for the processed keyframes, the corner extraction algorithm based on contours are used to obtain all corner points and pixel length of notch. Finally, the actual length is calculated by setting constraints on positional parameters. When tested in industrial environment, our algorithm can extract the corner points and calculate the notch length accurately and quickly. The average error of corner extraction is about 0.4%, and the measurement error of notch length is less than 1%. Compared with other methods, the algorithm has the advantages of speed and accuracy in dealing with rectangular plastic notches.