A Method for the Evaluation and Classification of the Orange Peel Effect on Painted Injection Moulded Part Surfaces

摘要

Orange peel effect, the wavy appearance on the surface, is one of the frequently encountered defects on the painted injection moulded parts. In this work, a method for evaluation and classification of the orange peel effect on a black-painted high-gloss surface using image processing and frequency analysis is presented. A monochrome camera is used to acquire images from the surface of the part, while an LED-bar is illuminating it. Because the part is complex shaped, in order to inspect the whole surface, a robotic manipulator is used to handle the part in front of the camera. After taking images, the region of interest (the region in the image illuminated by the light source) is selected manually. Based on the result of the image processing and frequency analysis assessing the waviness of the ROI, a score to evaluate and classify the intensity of the orange peel effect is calculated. Finally, the outcomes of this method are compared with the subjective evaluation of the experts, in order to examine the reliability of the evaluation method.