Name
circularitycircularityCircularityCircularity — Shape factor for the circularity (similarity to a circle) of a region.
The operator circularitycircularityCircularityCircularityCircularity calculates the similarity of
the input region with a circle.
- Calculation:
-
If F is the area of the region and max is the maximum distance from
the center to all contour pixels, the shape factor C
is defined as:
C = min(1,C')
The shape factor C of a circle is 1. If the region
is long or has holes, C is smaller than 1.
The operator circularitycircularityCircularityCircularityCircularity especially responds to large bulges,
holes and unconnected regions. The value of C is clipped to 1.0,
because the pixel area of a region can only be an approximation of a
real circle's area. This approximation error is bigger for small
regions than for large regions.
In the documentation of this chapter (Regions / Features), you can
find an image illustrating regions which vary in their circularity.
In case of an empty region the operator circularitycircularityCircularityCircularityCircularity returns the
value 0 (if no other behavior was set (see set_systemset_systemSetSystemSetSystemSetSystem)).
If more than one region is passed the numerical values of the shape
factor are stored in a tuple, the position of a value in the tuple corresponding
to the position of the region in the input tuple.
- Multithreading type: reentrant (runs in parallel with non-exclusive operators).
- Multithreading scope: global (may be called from any thread).
- Automatically parallelized on tuple level.
Region(s) to be examined.
Circularity of the input region(s).
Assertion: 0 <= Circularity && Circularity <= 1.0
* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate: ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse: ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle: ',M_C])
fnew_line(FileId)
/* Comparison between shape factors of rectangle, circle and ellipse */
gen_rectangle1(&R1,10.0,10.0,20.0,20.0);
gen_rectangle2(&R2,100.0,100.0,0.0,100.0,20.0);
gen_ellipse(&E,100.0,100.0,0.0,100.0,20.0);
gen_circle(&C,100.0,100.0,20.0);
circularity(R1,&R1_);
circularity(R2,&R2_);
circularity(E,&E_);
circularity(C,&C_);
printf("quadrate: %g\n",R1_);
printf("rectangle: %g\n",R2_);
printf("ellipse: %g\n",E_);
printf("circle: %g\n",C_);
* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate: ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse: ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle: ',M_C])
fnew_line(FileId)
* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate: ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse: ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle: ',M_C])
fnew_line(FileId)
* Comparison between shape factors of rectangle, circle and ellipse:
gen_rectangle1(R1,10,10,20,20)
gen_rectangle2(R2,100,100,0.0,100,20)
gen_ellipse(E100,100,100,0.0,100,20)
gen_circle(C,100,100,20)
circularity(R1,M_R1)
circularity(R2,M_R2)
circularity(E100,M_E)
circularity(C,M_C)
fwrite_string(FileId,['quadrate: ',M_R1])
fnew_line(FileId)
fwrite_string(FileId,['rectangle: ',M_R2])
fnew_line(FileId)
fwrite_string(FileId,['ellipse: ',M_E])
fnew_line(FileId)
fwrite_string(FileId,['circle: ',M_C])
fnew_line(FileId)
The operator circularitycircularityCircularityCircularityCircularity returns the value 2 (H_MSG_TRUE)
if the input is not empty.
The behavior in case of empty input (no input regions available) is
set via the operator set_system('no_object_result',<Result>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>).
The behavior in case of empty region (the region is the empty set) is set via
set_system('empty_region_result',<Result>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>).
If necessary an exception is raised.
thresholdthresholdThresholdThresholdThreshold,
regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowing,
connectionconnectionConnectionConnectionConnection
roundnessroundnessRoundnessRoundnessRoundness,
compactnesscompactnessCompactnessCompactnessCompactness,
convexityconvexityConvexityConvexityConvexity,
eccentricityeccentricityEccentricityEccentricityEccentricity
area_centerarea_centerAreaCenterAreaCenterAreaCenter,
select_shapeselect_shapeSelectShapeSelectShapeSelectShape
Foundation