zero_crossingzero_crossingZeroCrossingZeroCrossing (Operator)

Name

zero_crossingzero_crossingZeroCrossingZeroCrossing — Extract zero crossings from an image.

Signature

Description

zero_crossingzero_crossingZeroCrossingZeroCrossingZeroCrossing returns the zero crossings of the input image as a region. A pixel is accepted as a zero crossing if its gray value (in ImageImageImageImageimage) is zero, or if at least one of its neighbors of the 4-neighborhood has a different sign.

This operator is intended to be used after edge operators returning the second derivative of the image (e.g., laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss), which were possibly followed by a smoothing operator. In this case, the zero crossings are (candidates for) edges.

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 domain level.

Parameters

Result

zero_crossingzero_crossingZeroCrossingZeroCrossingZeroCrossing usually returns the value 2 (H_MSG_TRUE). If necessary, an exception is raised.

Possible Predecessors

laplacelaplaceLaplaceLaplaceLaplace, laplace_of_gausslaplace_of_gaussLaplaceOfGaussLaplaceOfGaussLaplaceOfGauss, derivate_gaussderivate_gaussDerivateGaussDerivateGaussDerivateGauss

Possible Successors

connectionconnectionConnectionConnectionConnection, skeletonskeletonSkeletonSkeletonSkeleton, boundaryboundaryBoundaryBoundaryBoundary, select_shapeselect_shapeSelectShapeSelectShapeSelectShape, fill_upfill_upFillUpFillUpFillUp

Alternatives

thresholdthresholdThresholdThresholdThreshold, dual_thresholddual_thresholdDualThresholdDualThresholdDualThreshold, zero_crossing_sub_pixzero_crossing_sub_pixZeroCrossingSubPixZeroCrossingSubPixZeroCrossingSubPix

Module

Foundation