TWO COLOUR VISION SYSTEM

A vision system for viewing the end face of product mounted in a machine which in use produces measurements relating to the area of the end face and of at least one constituent part of the product which is visible in the end face. The end face is illuminated by light of two different wavelengths. One wavelength illuminates an area which contains both the end face and surrounding parts of the machine, while light of the other wavelength from a laser source produces a pattern of parallel spaced apart lines of light of the other wavelength. The parallel lines cross the end face at a specific given angle. Gating excludes video signal of parallel lines in the image which are not at the specific angle to leave a residual video signal corresponding to the end face. A full color video signal of the field of view is gated by the mask.