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Smart Matching
9.1
Smart Matching
Notes
Search accuracy
The search accuracy of the matching checker can be set to±
16, 8, 4, 2, or 1 pixel, or to sub pixels in each processing step.
The matching checker compresses the template image and
searches the search area, and the degree of compression
used in conducting the search is set by setting the search
accuracy (by setting±a certain number of pixels or sub
pixels). The accuracy setting is the unit that compresses the
template image.
For example, an accuracy setting of±16 pixels will compress
the template image in the ratio of 16×16 pixels to one. At this
setting, the search will be conducted very quickly, but the
accuracy will be lower than at other settings.
Conversely, if the image compression is performed in sub
pixel units, a highly accurate search will be performed, but the
image processing will take some time. Thus, to process the
image quickly but without compromising accuracy, try using
different settings to adjust the image compression rate so that
the Imagechecker can search the template image most
effectively.
The search is performed in five steps. In the 1st step (±16
pixels), the Imagechecker will search for images that are
roughly similar to the sample image. In the 2nd step, it will
process only the areas detected in the 1st step with a higher
degree of accuracy than in the 1st step.
It can then quickly search the template image with a high
degree of accuracy if the accuracy settings are increased in
the 3rd and 4th steps. Thus you can change fine−tune the
settings to adjust the processing time and accuracy.
When the Imagechecker is performing a search in steps to
search a compressed image, it may go outside the search
area. If this occurs, the correlation value results will be
displayed as "– – –", an undetected error will be generated
without a completed search, and the judgment will be NG.
9 − 8
OCR Type A230
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