Abstract: The invention relates to a method and an arrangement implementing the method of inspecting the surface of an object (106), the method comprising providing a movement between the object and the arrangement for inspecting the surface of the object, the surface of the object being radiated with optical radiation. Said radiation is directed to different imaging fields (108, 110) of the surface of the object so that at least one property of each radiation is different in the different imaging fields. For the creation of image information from the same surface area of the object at different radiations, an image is produced of the imaging fields and the image information of the same surface area obtained from different imaging fields is compared and/or combined to create surface inspection information.

Abstract: In a method an an apparatus for automatic inspection of moving surfaces using at least three different illumination/observation channels, the surface to be inspected under a bright field condition is illuminated by a first beam of light from a first light source. The light of the first beam of light reemitted from the surface is received by a light sensitive sensor device to obtain a first signal. Then, the surface is illuminated under a dark field condition by a second beam of light and by a third beam of light from a second and a third light source, respectively, the first, second and third beams of light having different characteristics. The light of the second beam of light and the light of the third beam of light, respectively, reemitted from the surface are received by the light sensitive sensor device to obtain a second signal and a third signal. Finally, a physical property of the surface is derived from the first, second and third signals.

Abstract: A method and an apparatus for measuring the wall thickness of a plastic article, particularly of a hollow rotation-symmetrical plastic article. According to the method, the wall of the plastic article is subjected to infra-red radiation and the intensity of, e.g., the continuously transmitted radiation is measured at preselected points, said intensity being a function of the wall thickness to be measured. At the same time, on one hand, the plastic article and, on the other hand, a radiation source and/or a radiation detector are set in an axial and rotational movement in relation to each other.