Method for maximizing the contrast of an image

摘要

A method 100 maximizes the contrast between light and dark markings 13 that carry information. The markings are illuminated by a variable output light source 16, and a reflected image is received by a detector 18 and processed by a controller 20. The method calculates a histogram of the reflected image at step 102, and the method determines at step 104 if the histogram has one peak or two peaks. The method increases at step 110 or decreases at step 112 the output of the light source 16 by adding or subtracting a small step amount to or from the current light level of the light source 16. The method 100 is a continuously repeating loop, and the method increases or decreases the light level of the source of illumination with substantially every loop to oscillate about an equilibrium light level that provides maximum contrast.

主权项

1. A method for maximizing contrast in an optical system adapted for detecting a pattern formed from a plurality of dark and light markings and having a light source with a variable light level, the method comprising:
illuminating a portion of the pattern with light from the light source at an existing light level; gathering an image of the illuminated portion of the pattern; calculating a histogram from the image; identifying at least one peak in the calculated histogram; determining whether a brightest peak is near saturation; and increasing the light level from the light source when the brightest peak is not near saturation.