Omron FH-1 series User Manual page 533

Edge Detection Method
The following two types of edge detection method are available.
• Projection (Density method)
A projected waveform is formed relative to the density level. The intersection of the density and the
threshold (edge level) is detected as an edge.
With an image with high noise level or image with blurry edges, the density method is suitable as it
allows you to specify the density and color of the edges to be detected.
• Differential
A differential processing is performed to calculate the change in density between neighboring pixels.
A differential waveform with the largest density set as 100% of the region is created, and the maxi-
mum value (peak point) of the differential waveform that exceeds the threshold (edge level) is
detected as an edge.
With an image with low contrast, the differential method is suitable as it normalizes the differences
between the neighboring pixels for processing.
Vision System FH/FHV/FZ5 Series User's Manual (Z365)
255
Detection as an edge
255
Density
(Density level)
0
Density average
Change in density
255
200
150
Differential value
(Change in density)
100
50
0
170 133 70 20
Detection as an edge
Edge level
255 170 133 70 20
85 37 63 50
Detection as an edge
Edge level
Appendices
A
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