zero_crossing🔗
Short description🔗
zero_crossing — Extract zero crossings from an image.
Signature🔗
zero_crossing( image Image, out region RegionCrossing )
Description🔗
zero_crossing returns the zero crossings of the input
image as a region. A pixel is accepted as a zero crossing if its
gray value (in Image) is zero, or if at least one of its
neighbors of the 4-neighborhood has a different sign.
This operator is intended to be used after edge operators returning
the second derivative of the image (e.g., laplace_of_gauss),
which were possibly followed by a smoothing operator. In this case,
the zero crossings are (candidates for) edges.
Execution information🔗
Execution information
-
Multithreading type: reentrant (runs in parallel with non-exclusive operators).
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Multithreading scope: global (may be called from any thread).
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Automatically parallelized on tuple level.
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Automatically parallelized on domain level.
Parameters🔗
Image (input_object) singlechannelimage(-array) → object (int1 / int2 / int4 / real)
Input image.
RegionCrossing (output_object) region(-array) → object
Zero crossings.
Result🔗
zero_crossing usually returns the value 2 (H_MSG_TRUE). If
necessary, an exception is raised.
Combinations with other operators🔗
Combinations
Possible predecessors
laplace, laplace_of_gauss, derivate_gauss
Possible successors
connection, skeleton, boundary, select_shape, fill_up
Alternatives
Module🔗
Foundation