Panasonic A230 User Manual

Smart Matching OCR Type A2309 − 129.1 Smart MatchingDeviation processingAs shown in the diagram below, deviation processing is used when you only wantabnormalities outside the object workpiece to be recognized as differences, but notdifferences in the outline area of the object workpiece.Template Want this to be judged OK.Want these to be judged NG.The Imagechecker will use the deviation data for each pixel in the results obtainedduring the subtraction processing, and will revise the portions you do not want it torecognize as differences (the outline area in the example above) to the results belowthe threshold value. By doing this, the corresponding portion will appear as the finalresults of the binarization. Deviation data is set for each pixel in the template.As shown in the diagram below, with subtraction processing alone, differences in theoutline areas (difference: 128 > threshold value: 96) are recognized as black partsin the second row, but if deviation data is also used, the results of the outline portionsbecome equal to the threshold value (difference: 128 × deviation:0.75 = 96 threshold value), and are not recognized as abnormalities. On the otherhand, abnormalities that exceed the threshold value (difference: 128 × deviation: 1.0= 128 > threshold value) are recognized as such.Area where the outlinefluctuates due to theworkpiece. Difference = 128 Deviation = 0.75Deviation = 1.0Deviation data