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rectangularityRectangularityRectangularityrectangularityrectangularity🔗

Short description🔗

rectangularityRectangularityRectangularityrectangularityrectangularity — Shape factor for the rectangularity of a region.

Signature🔗

rectangularity( region Regions, out real Rectangularity )void Rectangularity( const HObject& Regions, HTuple* Rectangularity )static void HOperatorSet.Rectangularity( HObject regions, out HTuple rectangularity )def rectangularity( regions: HObject ) -> Sequence[float]

def rectangularity_s( regions: HObject ) -> floatHerror rectangularity( const Hobject Regions, double* Rectangularity )

Herror T_rectangularity( const Hobject Regions, Htuple* Rectangularity )

HTuple HRegion::Rectangularity( ) const

HTuple HRegion.Rectangularity( )

Description🔗

The operator rectangularityRectangularity calculates the rectangularity of the input regions.

To determine the rectangularity, first a rectangle is computed that has the same first and second order moments as the input region. The computation of the rectangularity measure is finally based on the area of the difference between the computed rectangle and the input region normalized with respect to the area of the rectangle.

In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their rectangularity.

For rectangles rectangularityRectangularity returns the value 1. The more the input region deviates from a perfect rectangle, the less the returned value for Rectangularityrectangularityrectangularity will be.

In case of an empty region the operator rectangularityRectangularity returns the value 0 (if no other behavior was set (see set_systemSetSystem)). If more than one region is passed the numerical values of the rectangularity are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.

Attention🔗

For input regions which orientation cannot be computed by using second order moments (as it is the case for square regions, for example), the returned Rectangularityrectangularityrectangularity is underestimated by up to 10% depending on the orientation of the input region.

Execution information🔗

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🔗

Regionsregionsregions (input_object) region(-array) → objectHObjectHRegionHObjectHobject

Region(s) to be examined.

Rectangularityrectangularityrectangularity (output_control) real(-array) → (real)HTuple (double)HTuple (double)Sequence[float]Htuple (double)

Rectangularity of the input region(s).

Assertion: 0 <= Rectangularity && Rectangularity <= 1.0

Result🔗

The operator rectangularityRectangularity 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>). The behavior in case of empty region (the region is the empty set) is set via set_system('empty_region_result',<Result>). If necessary an exception is raised.

Combinations with other operators🔗

Combinations

Possible predecessors

thresholdThreshold, regiongrowingRegiongrowing, connectionConnection

Alternatives

circularityCircularity, compactnessCompactness, convexityConvexity, eccentricityEccentricity

See also

contlengthContlength, area_centerAreaCenter, select_shapeSelectShape

References🔗

P. L. Rosin: “Measuring rectangularity”; Machine Vision and Applications; vol. 11; pp. 191-196; Springer-Verlag, 1999.

Module🔗

Foundation