Advertisement
OCR Type A230
Smart Matching
9.1
Smart Matching
Subtraction processing
Performs subtraction processing on the points detected by the matching checker.
The results are output as the area of the portion where the search image and
template images do not match. It overlaps the search image and the template image
at the detected points, and processes them as follows:
The Imagechecker calculates the difference in brightness between the search
image (f(x,y)) and the template (g(x,y)). If the absolute value of the difference is
larger than the threshold level (th), the result will be 1; if it is smaller, the result will
be 0. It will search for the number of pixels where the result is 1 to find the area size
(S) of the differential, and will output that number as the result. It can perform the
same filter processing as other binary checkers on pixels where the result is 1.
Search image
Template
Difference calculation
Difference = 64
Difference = 128
Binarization
Difference = 0
Threshold level = 96
Final results
Subtraction results
9 − 11
Advertisement
