smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2 (Operator)
Name
smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2 — Smallest surrounding rectangle with any orientation.
Signature
Herror smallest_rectangle2(const Hobject Regions, double* Row, double* Column, double* Phi, double* Length1, double* Length2)
Herror T_smallest_rectangle2(const Hobject Regions, Htuple* Row, Htuple* Column, Htuple* Phi, Htuple* Length1, Htuple* Length2)
void SmallestRectangle2(const HObject& Regions, HTuple* Row, HTuple* Column, HTuple* Phi, HTuple* Length1, HTuple* Length2)
void HRegion::SmallestRectangle2(HTuple* Row, HTuple* Column, HTuple* Phi, HTuple* Length1, HTuple* Length2) const
void HRegion::SmallestRectangle2(double* Row, double* Column, double* Phi, double* Length1, double* Length2) const
static void HOperatorSet.SmallestRectangle2(HObject regions, out HTuple row, out HTuple column, out HTuple phi, out HTuple length1, out HTuple length2)
void HRegion.SmallestRectangle2(out HTuple row, out HTuple column, out HTuple phi, out HTuple length1, out HTuple length2)
void HRegion.SmallestRectangle2(out double row, out double column, out double phi, out double length1, out double length2)
Description
The operator smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2 determines the smallest
surrounding rectangle of a region, i.e., the rectangle with the smallest
area of all rectangles containing the region.
For this rectangle the center,
the inclination and the two radii are calculated.
The calculation of the rectangle is based on the center coordinates of
the region pixels.
In the documentation of this chapter (Regions / Features), you can
find an image illustrating regions which vary in the length and phi of their
smallest surrounding rectangle.
The operator is applied when, for example, the location of a scenery of
several regions (e.g., printed text on a rectangular paper or
in rectangular print (justified lines)) must be found.
The parameters of smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2 are chosen in such a way
that they can be used directly as input for the operators
disp_rectangle2disp_rectangle2DispRectangle2DispRectangle2DispRectangle2 and gen_rectangle2gen_rectangle2GenRectangle2GenRectangle2GenRectangle2.
If more than one region is passed in RegionsRegionsRegionsRegionsregions the results are
stored in tuples, the index of a value in the tuple corresponding to the
index of a region in the input. In case of empty region all parameters
have the value 0.0 if no other behavior was set (see set_systemset_systemSetSystemSetSystemSetSystem).
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
RegionsRegionsRegionsRegionsregions (input_object) region(-array) → objectHRegionHRegionHobject
Regions to be examined.
RowRowRowRowrow (output_control) rectangle2.center.y(-array) → HTupleHTupleHtuple (real) (double) (double) (double)
Line index of the center.
ColumnColumnColumnColumncolumn (output_control) rectangle2.center.x(-array) → HTupleHTupleHtuple (real) (double) (double) (double)
Column index of the center.
PhiPhiPhiPhiphi (output_control) rectangle2.angle.rad(-array) → HTupleHTupleHtuple (real) (double) (double) (double)
Orientation of the surrounding rectangle (arc measure)
Assertion: - pi / 2 < Phi && Phi <= pi / 2
Length1Length1Length1Length1length1 (output_control) rectangle2.hwidth(-array) → HTupleHTupleHtuple (real) (double) (double) (double)
First radius (half length) of the surrounding
rectangle.
Assertion: Length1 >= 0.0
Length2Length2Length2Length2length2 (output_control) rectangle2.hheight(-array) → HTupleHTupleHtuple (real) (double) (double) (double)
Second radius (half width) of the surrounding
rectangle.
Assertion: Length2 >= 0.0 && Length2 <= Length1
Example (HDevelop)
read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)
Example (HDevelop)
read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)
Example (HDevelop)
read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)
Example (HDevelop)
read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)
Example (HDevelop)
read_image(Image,'fabrik')
regiongrowing(Image,Regions,5,5,6,100)
smallest_rectangle2(Regions,Row,Column,Phi,Length1,Length2)
gen_rectangle2(Rectangle,Row,Column,Phi,Length1,Length2)
dev_set_draw ('margin')
dev_display(Rectangle)
Complexity
If F is the area of the region and N is the number of supporting points
of the convex hull, the runtime complexity is O(sqrt(F) + N^2).
Result
The operator smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2SmallestRectangle2 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.
Possible Predecessors
thresholdthresholdThresholdThresholdThreshold,
regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowing,
connectionconnectionConnectionConnectionConnection,
runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeatures
Possible Successors
disp_rectangle2disp_rectangle2DispRectangle2DispRectangle2DispRectangle2,
gen_rectangle2gen_rectangle2GenRectangle2GenRectangle2GenRectangle2
Alternatives
elliptic_axiselliptic_axisEllipticAxisEllipticAxisEllipticAxis,
smallest_rectangle1smallest_rectangle1SmallestRectangle1SmallestRectangle1SmallestRectangle1
See also
smallest_circlesmallest_circleSmallestCircleSmallestCircleSmallestCircle,
set_shapeset_shapeSetShapeSetShapeSetShape
Module
Foundation