CONTRAST DETERMINING APPARATUS AND METHODS

摘要

Apparatus for determining the contrast of a mark, for example lettering on a cable, uses a CCD sensor or the like to capture a two-dimensional image of the Mark. The pixel values from the CCD are thresholded into populations of black, grey and white. The average intensities of the "black" and "white" pixels are taken and an indicator of contrast obtained from the following formula: contrast = (I max - I min)/ I max where I max = average "white" pixels, I min = average "black" pixels.