SoZeroCrossingsProcessing2d Class Reference
[Edge Marking]

ImageViz SoZeroCrossingsProcessing2d engine More...

#include <ImageViz/Engines/EdgeDetection/EdgeMarking/SoZeroCrossingsProcessing2d.h>

Inheritance diagram for SoZeroCrossingsProcessing2d:
SoImageVizEngine SoEngine SoFieldContainer SoBase SoRefCounter SoTypedObject

List of all members.

Public Member Functions

 SoZeroCrossingsProcessing2d ()

Public Attributes

SoSFImageDataAdapter inImage
SoImageVizEngineOutput
< SoSFImageDataAdapter,
SoImageDataAdapter * > 
outBinarylImage

Detailed Description

ImageViz 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.

SoZeroCrossings_image01.png

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.

SoZeroCrossings_image02.png

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


Library references: zero_crossings


Constructor & Destructor Documentation

SoZeroCrossingsProcessing2d::SoZeroCrossingsProcessing2d (  ) 

Constructor.


Member Data Documentation

The input image.

Default value is NULL. Supported types include: grayscale binary label color image.

The output binary image.

Default value is NULL. Supported types include: binary image.


The documentation for this class was generated from the following file:

Open Inventor Toolkit reference manual, generated on 12 Feb 2024
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