Package com.openinventor.imageviz.engines.edgedetection.edgemarking

Class SoZeroCrossingsProcessing2d

  • All Implemented Interfaces:
    SafeDisposable
    @Deprecated(since="2023.2")
public class SoZeroCrossingsProcessing2d
extends SoImageVizEngine
    Deprecated.
    As of Open Inventor 2023.2. ImageViz API is replaced by the new ImageDev toolkit.
    SoZeroCrossingsProcessing2d engine. For an introduction to edge marking, see section Introduction to Edge Marking.

    Zero-crossings are points where the Laplacian switches from positive to negative values, and vice versa.

    A simple zero-crossing detection is obtained by thresholding the Laplacian to retain positive intensities, then detecting the boundaries of the binary image, as in Figure 1. Such zero-crossing points are not precisely located.

    Figure 1: Thresholding a laplacian to determine the zero crossings ZERO-CROSSINGS is even better to mark a point if the laplacian changes its sign in its 3x3 neighbourhood, and if the laplacian magnitude is smaller than all magnitudes in that neighbourhood, as in Figure 2.

    Figure 2: Zero-crossing a laplacian Compared to thresholding of a gradient, zero-crossings have the advantage of producing closed curves of 1 pixel thickness. This is most interesting when precise object boundary detection is the goal.

    File format/default:

    ZeroCrossingsProcessing2d {

      inImage NULL
    }


    Library references: zero_crossings

    • Constructor Detail

      • SoZeroCrossingsProcessing2d

        public SoZeroCrossingsProcessing2d()
        Deprecated.
        Constructor.