threshold_sub_pix — Extract level crossings from an image with subpixel accuracy.
threshold_sub_pix extracts the level crossings at the level
Threshold of the input image
Image with subpixel
accuracy. The extracted level crossings are returned as
Border. In contrast to the
threshold_sub_pix does not
return regions, but the lines that separate regions with a gray
value less than
Threshold from regions with a gray value
For the extraction, the input image is regarded as a surface, in
which the gray values are interpolated bilinearly between the
centers of the individual pixels. Consistent with the surface thus
defined, level crossing lines are extracted for each pixel and
linked into topologically sound contours. This means that the level
crossing contours are correctly split at junction points. If the
image contains extended areas of constant gray value
Threshold, only the border of such areas is returned as
→object (byte / int1 / int2 / uint2 / int4 / real)
Extracted level crossings.
→(real / integer)
Threshold for the level crossings.
Default value: 128
Suggested values: 0.0, 10.0, 30.0, 64.0, 128.0, 200.0, 220.0, 255.0
read_image(Image,'fabrik') threshold_sub_pix(Image,Border,35) dev_display(Border)
threshold_sub_pix usually returns the value 2 (H_MSG_TRUE). If
necessary, an exception is raised.