threshold threshold Threshold Threshold threshold (Operator)
threshold threshold Threshold Threshold threshold
Signature
def threshold (image min_gray max_gray
Description
threshold threshold Threshold Threshold threshold
All points of an image fulfilling the condition are returned as one
region. If more than one gray value interval is passed (tuples for
MinGray MinGray MinGray minGray min_gray MaxGray MaxGray MaxGray maxGray max_gray MinGray MinGray MinGray minGray min_gray MaxGray MaxGray MaxGray maxGray max_gray 'min' "min" "min" "min" "min" 'max' "max" "max" "max" "max"
Attention
The usage of MinGray MinGray MinGray minGray min_gray MaxGray MaxGray MaxGray maxGray max_gray
For images of type integer, floating point values in MinGray MinGray MinGray minGray min_gray MaxGray MaxGray MaxGray maxGray max_gray MinGray MinGray MinGray minGray min_gray MaxGray MaxGray MaxGray maxGray max_gray
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.
Automatically parallelized on internal data level.
Parameters
Image Image Image image image singlechannelimage(-array) → object HImage HObject HObject Hobject (byte / direction / cyclic / int1 / int2 / uint2 / int4 / int8 / real / vector_field)
Input image.
Region Region Region region region region(-array) → object HRegion HObject HObject Hobject *
Segmented region.
MinGray MinGray MinGray minGray min_gray number(-array) → HTuple MaybeSequence[Union[int, float, str]] HTuple Htuple (real / integer / string) (double / int / long / string) (double / Hlong / HString) (double / Hlong / char*)
Lower threshold for the gray values or 'min' "min" "min" "min" "min"
Default:
128.0
Suggested values:
0.0, 10.0, 30.0, 64.0, 128.0, 200.0, 220.0, 255.0, 'min' "min" "min" "min" "min"
MaxGray MaxGray MaxGray maxGray max_gray number(-array) → HTuple MaybeSequence[Union[int, float, str]] HTuple Htuple (real / integer / string) (double / int / long / string) (double / Hlong / HString) (double / Hlong / char*)
Upper threshold for the gray values or 'max' "max" "max" "max" "max"
Default:
255.0
Suggested values:
0.0, 10.0, 30.0, 64.0, 128.0, 200.0, 220.0, 255.0, 'max' "max" "max" "max" "max"
Restriction:
MaxGray >= MinGray
Example (HDevelop)
read_image(Image,'fabrik')
sobel_dir(Image,EdgeAmp,EdgeDir,'sum_abs',3)
threshold(EdgeAmp,Seg,50,255)
skeleton(Seg,Rand)
connection(Rand,Lines)
select_shape(Lines,Edges,'area','and',10,1000000)
Example (C)
read_image(&Image,"fabrik");
sobel_amp(Image,&EdgeAmp,"sum_abs",3);
threshold(EdgeAmp,&Seg,50.0,255.0);
skeleton(Seg,&Rand);
connection(Rand,&Lines);
select_shape(Lines,&Edges,"area","and",10.0,1000000.0);
Example (C++)
#include "HIOStream.h"
#if !defined(USE_IOSTREAM_H)
using namespace std;
#endif
#include "HalconCpp.h"
using namespace Halcon;
int main (int argc, char *argv[])
{
if (argc != 4)
{
cout << "Usage : " << argv[0] << " 'image' MinGray MaxGray" << endl;
return (-1);
}
HImage image (argv[1]),
Sobel;
HWindow win;
image.Display (win);
int MinGray = atoi (argv[2]);
int MaxGray = atoi (argv[3]);
Sobel = image.SobelAmp ("sum_abs", 3);
HRegionArray rand = ((image >= MinGray) & (image <= MaxGray)).Skeleton();
HRegionArray lines = rand.Connection();
HRegionArray edges = lines.SelectShape("area", "and", 10.0, 10000000.0);
edges.Display (win);
win.Click ();
return (0);
}
Example (HDevelop)
read_image(Image,'fabrik')
sobel_dir(Image,EdgeAmp,EdgeDir,'sum_abs',3)
threshold(EdgeAmp,Seg,50,255)
skeleton(Seg,Rand)
connection(Rand,Lines)
select_shape(Lines,Edges,'area','and',10,1000000)
Complexity
Let A be the area of the input region. Then the runtime
complexity is O(A).
Result
threshold threshold Threshold Threshold threshold 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" 'empty_region_result' "empty_region_result" "empty_region_result" "empty_region_result" "empty_region_result" 'store_empty_region' "store_empty_region" "store_empty_region" "store_empty_region" "store_empty_region" set_system set_system SetSystem SetSystem set_system
Possible Predecessors
histo_to_thresh histo_to_thresh HistoToThresh HistoToThresh histo_to_thresh min_max_gray min_max_gray MinMaxGray MinMaxGray min_max_gray sobel_amp sobel_amp SobelAmp SobelAmp sobel_amp binomial_filter binomial_filter BinomialFilter BinomialFilter binomial_filter gauss_filter gauss_filter GaussFilter GaussFilter gauss_filter reduce_domain reduce_domain ReduceDomain ReduceDomain reduce_domain fill_interlace fill_interlace FillInterlace FillInterlace fill_interlace
Possible Successors
connection connection Connection Connection connection dilation1 dilation1 Dilation1 Dilation1 dilation1 erosion1 erosion1 Erosion1 Erosion1 erosion1 opening opening Opening Opening opening closing closing Closing Closing closing rank_region rank_region RankRegion RankRegion rank_region shape_trans shape_trans ShapeTrans ShapeTrans shape_trans skeleton skeleton Skeleton Skeleton skeleton
Alternatives
class_2dim_sup class_2dim_sup Class2dimSup Class2dimSup class_2dim_sup hysteresis_threshold hysteresis_threshold HysteresisThreshold HysteresisThreshold hysteresis_threshold dyn_threshold dyn_threshold DynThreshold DynThreshold dyn_threshold binary_threshold binary_threshold BinaryThreshold BinaryThreshold binary_threshold char_threshold char_threshold CharThreshold CharThreshold char_threshold auto_threshold auto_threshold AutoThreshold AutoThreshold auto_threshold dual_threshold dual_threshold DualThreshold DualThreshold dual_threshold
See also
zero_crossing zero_crossing ZeroCrossing ZeroCrossing zero_crossing background_seg background_seg BackgroundSeg BackgroundSeg background_seg regiongrowing regiongrowing Regiongrowing Regiongrowing regiongrowing
Module
Foundation