Method for detecting surface defects e.g. cracks at plastic surface of corrugated pipe, involves testing differential image between two partial region images to determine whether coherent regions are provided with grey values

摘要

The method involves receiving an image from a surface of an object i.e. pipe section (2), by a camera. The image is divided into number of partial region images (4), and an inverted partial region image (12) is produced from a partial region image (6). The inverted partial region image is superimposed with another partial region image (8). A differential image (14) between the partial region images is tested to determine whether coherent regions are provided with grey values that differ from a tolerance value. The two partial region images are partially overlapped. An independent claim is also included for a device for detecting surface defects.