background_segbackground_segBackgroundSegBackgroundSegbackground_seg (Operator)
background_segbackground_segBackgroundSegBackgroundSegbackground_seg — Determine the connected components of the background of given regions.
Signature
def background_seg(foreground: HObject) -> HObject
Description
background_segbackground_segBackgroundSegBackgroundSegbackground_seg determines connected components of the
background of the foreground regions given in ForegroundForegroundForegroundforegroundforeground.
This operator is normally used after an edge operator in order to
determine the regions enclosed by the extracted edges. The
connected components are determined using 4-neighborhood.
Execution Information
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Processed without parallelization.
Parameters
ForegroundForegroundForegroundforegroundforeground (input_object) region(-array) → objectHRegionHObjectHObjectHobject
Input regions.
BackgroundRegionsBackgroundRegionsBackgroundRegionsbackgroundRegionsbackground_regions (output_object) region-array → objectHRegionHObjectHObjectHobject *
Connected components of the background.
Example (HDevelop)
* Simulation of background_seg:
background_seg(Foreground,BackgroundRegions)
complement(Foreground,Background)
get_system('neighborhood',Save)
set_system('neighborhood',4)
connection(Background,BackgroundRegions)
set_system('neighborhood',Save)
* Segmentation with edge filter:
read_image(Image,'fabrik')
sobel_dir(Image,Sobel,Dir,'sum_sqrt',3)
threshold(Sobel,Edges,20,255)
skeleton(Edges,Margins)
background_seg(Margins,Regions)
Example (C)
/* Segmentation with edge filter: */
read_image(&Image,"fabrik");
sobel_dir(Image,&Sobel,&Dir,"sum_sqrt",3);
threshold(Sobel,&Edges,20,255);
skeleton(Edges,&Margins);
background_seg(Margins,&Regions);
Example (HDevelop)
* Simulation of background_seg:
background_seg(Foreground,BackgroundRegions)
complement(Foreground,Background)
get_system('neighborhood',Save)
set_system('neighborhood',4)
connection(Background,BackgroundRegions)
set_system('neighborhood',Save)
* Segmentation with edge filter:
read_image(Image,'fabrik')
sobel_dir(Image,Sobel,Dir,'sum_sqrt',3)
threshold(Sobel,Edges,20,255)
skeleton(Edges,Margins)
background_seg(Margins,Regions)
Example (HDevelop)
* Simulation of background_seg:
background_seg(Foreground,BackgroundRegions)
complement(Foreground,Background)
get_system('neighborhood',Save)
set_system('neighborhood',4)
connection(Background,BackgroundRegions)
set_system('neighborhood',Save)
* Segmentation with edge filter:
read_image(Image,'fabrik')
sobel_dir(Image,Sobel,Dir,'sum_sqrt',3)
threshold(Sobel,Edges,20,255)
skeleton(Edges,Margins)
background_seg(Margins,Regions)
Complexity
Let F be the area of the background, H and W be the height and
width of the image, and N be the number of resulting regions.
Then the runtime complexity is O(H + sqrt(F) * sqrt(N)).
Result
background_segbackground_segBackgroundSegBackgroundSegbackground_seg always returns the value 2 (
H_MSG_TRUE)
. The
behavior in case of empty input (no regions given) can be set via
set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)set_system("no_object_result",<Result>)
and the behavior in case of an empty input region via
set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)set_system("empty_region_result",<Result>).
If necessary, an exception is raised.
Possible Predecessors
thresholdthresholdThresholdThresholdthreshold,
connectionconnectionConnectionConnectionconnection,
regiongrowingregiongrowingRegiongrowingRegiongrowingregiongrowing,
pouringpouringPouringPouringpouring,
class_ndim_normclass_ndim_normClassNdimNormClassNdimNormclass_ndim_norm
Possible Successors
select_shapeselect_shapeSelectShapeSelectShapeselect_shape
Alternatives
complementcomplementComplementComplementcomplement,
connectionconnectionConnectionConnectionconnection
See also
thresholdthresholdThresholdThresholdthreshold,
hysteresis_thresholdhysteresis_thresholdHysteresisThresholdHysteresisThresholdhysteresis_threshold,
skeletonskeletonSkeletonSkeletonskeleton,
expand_regionexpand_regionExpandRegionExpandRegionexpand_region,
set_systemset_systemSetSystemSetSystemset_system,
sobel_ampsobel_ampSobelAmpSobelAmpsobel_amp,
edges_imageedges_imageEdgesImageEdgesImageedges_image,
robertsrobertsRobertsRobertsroberts,
bandpass_imagebandpass_imageBandpassImageBandpassImagebandpass_image
Module
Foundation