Abstract: A profile of a surface of an object (12) that has a longitudinal axis is determined by arranging a camera (14) to view a portion of the surface with its viewing axis (15) substantially perpendicular to the longitudinal axis, and arranging two scanning light sources (16, 18) to define planes of illumination which define two lines on the surface, so that the camera produces an image including images of the two lines. From the separation of the two lines in the image the surface profile can be determined. The planes of illumination are preferably inclined to one another, as this can enhance sensitivity.