SYSTEM AND METHOD FOR DETERMINING A THRESHOLD FOR EDGE DETECTION BASED ON AN UNDIFFERENTIATED EQUALIZED SCAN LINE SIGNAL

摘要

Methods and systems better detect edges in a binary optical code. One method constructs a threshold signal to be used for comparison with an equalized undifferentiated scan line signal imperfectly representing a binary optical code. The method comprises detecting peaks in the equalized undifferentiated scan line signal (115), determining midpoints (505) between the successive detected peaks (310), and generating a smooth signal (125) based on the midpoints. The generated signal is the 'threshold signal (125). In one version of the method, the generating step comprises interpolating between successive midpoints so as to result in a signal passing through the midpoints and low-pass filtering the signal passing through the midpoints so as to result in a filtered signal, which is the threshold signal. In another version of the method, the generating step comprises performing regression using the midpoints so as to generate a signal curve that fits the midpoints according to a criterion. Software, digital and analog techniques are described.