nonmax_suppression_ampnonmax_suppression_ampNonmaxSuppressionAmpNonmaxSuppressionAmpnonmax_suppression_amp (Operator)
Name
nonmax_suppression_ampnonmax_suppression_ampNonmaxSuppressionAmpNonmaxSuppressionAmpnonmax_suppression_amp — Suppress non-maximum points on an edge.
Signature
def nonmax_suppression_amp(img_amp: HObject, mode: str) -> HObject
Description
nonmax_suppression_ampnonmax_suppression_ampNonmaxSuppressionAmpNonmaxSuppressionAmpNonmaxSuppressionAmpnonmax_suppression_amp suppresses all points in the
regions of the image ImgAmpImgAmpImgAmpImgAmpimgAmpimg_amp whose gray values are
not local (directed) maxima. In contrast to
nonmax_suppression_dirnonmax_suppression_dirNonmaxSuppressionDirNonmaxSuppressionDirNonmaxSuppressionDirnonmax_suppression_dir, a direction image is not needed.
Two modes of operation can be selected:
- 'hvnms'
A point is labeled as a local maximum if its gray value
is larger than or equal to the gray values within a search
space of pm 5 pixels, either horizontally or vertically.
Non-maximum points are removed from the region, gray
values remain unchanged.
- 'loc_max'
A point is labeled as a local maximum if its gray value
is larger than or equal to the gray values of its eight
neighbors.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
Parameters
ImgAmpImgAmpImgAmpImgAmpimgAmpimg_amp (input_object) singlechannelimage(-array) → objectHImageHObjectHImageHobject (byte / uint2 / real)
Amplitude (gradient magnitude) image.
ImageResultImageResultImageResultImageResultimageResultimage_result (output_object) singlechannelimage(-array) → objectHImageHObjectHImageHobject * (byte / uint2 / real)
Image with thinned edge regions.
ModeModeModeModemodemode (input_control) string → HTuplestrHTupleHtuple (string) (string) (HString) (char*)
Select horizontal/vertical or undirected NMS.
Default value:
'hvnms'
"hvnms"
"hvnms"
"hvnms"
"hvnms"
"hvnms"
List of values: 'hvnms'"hvnms""hvnms""hvnms""hvnms""hvnms", 'loc_max'"loc_max""loc_max""loc_max""loc_max""loc_max"
Result
nonmax_suppression_ampnonmax_suppression_ampNonmaxSuppressionAmpNonmaxSuppressionAmpNonmaxSuppressionAmpnonmax_suppression_amp returns 2 (H_MSG_TRUE) if all parameters
are correct. The behavior with respect to the input images and
output regions can be determined by setting the values of the flags
'no_object_result'"no_object_result""no_object_result""no_object_result""no_object_result""no_object_result", 'empty_region_result'"empty_region_result""empty_region_result""empty_region_result""empty_region_result""empty_region_result", and
'store_empty_region'"store_empty_region""store_empty_region""store_empty_region""store_empty_region""store_empty_region" with set_systemset_systemSetSystemSetSystemSetSystemset_system.
If necessary, an exception is raised.
Possible Predecessors
sobel_ampsobel_ampSobelAmpSobelAmpSobelAmpsobel_amp
Possible Successors
thresholdthresholdThresholdThresholdThresholdthreshold,
hysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThresholdHysteresisThresholdhysteresis_threshold
Alternatives
local_maxlocal_maxLocalMaxLocalMaxLocalMaxlocal_max,
nonmax_suppression_dirnonmax_suppression_dirNonmaxSuppressionDirNonmaxSuppressionDirNonmaxSuppressionDirnonmax_suppression_dir
See also
skeletonskeletonSkeletonSkeletonSkeletonskeleton
References
S.Lanser: “Detektion von Stufenkanten mittels rekursiver Filter nach
Deriche”; Diplomarbeit; Technische Universität München, Institut
für Informatik, Lehrstuhl Prof. Radig; 1991.
J.Canny: “Finding Edges and Lines in Images”; Report, AI-TR-720;
M.I.T. Artificial Intelligence Lab., Cambridge, MA; 1983.
Module
Foundation