com.openinventor.imageviz.engines.edgedetection.gradient

Class SoGradientOperatorProcessing2d

java.lang.Object

com.openinventor.inventor.Inventor

com.openinventor.inventor.misc.SoBase

com.openinventor.inventor.fields.SoFieldContainer

com.openinventor.inventor.engines.SoEngine

com.openinventor.imageviz.engines.SoImageVizEngine

com.openinventor.imageviz.engines.edgedetection.gradient.SoGradientOperatorProcessing2d

All Implemented Interfaces:

SafeDisposable

public class SoGradientOperatorProcessing2d
extends SoImageVizEngine

SoGradientOperatorProcessing2d engine provides different algorithms to extract the edges of a 2D image. For an introduction, see:

• section Images Filters
• section Edge Detection
• Introduction to Gradient

The SoGradientOperatorProcessing2d engine provides different algorithms to extract the edges of an image.

Note: You may normalize the filtered image, i.e. divide the output gray levels by the sum of absolute values of the kernel coefficients. If not, be aware that overflow may occur.

• Canny-Deriche: It performs a recursive gradient computation to get the gradient in X and Y directions. It is an FIR (finite impulse response) filter. To minimize the effect of noise, it smooths the image before computing the gradient. A smoothing scale parameter determines the smoothing intensity. If the value is large, noise will be reduced but edges will be less sharp and only the most significant edges will survive. It is important to select the right coefficient to lower the noise just enough without defocusing the edges. Then it gets the maximum of these images with a gradient magnitude operation. For color images it calculates the maximum of intensity or the euclidian mean.
• Shen-Castan: It calculates the gradient of Shen and Castan. It is a recursive and exponential filter that smooths an object and then extracts its edges. It is based on the Shen operator :

The highest is, the more edges we get. For color images it calculates the maximum of intensity or the euclidian mean.

• Canny: It performs an approximation to get the Canny-Deriche in X and Y directions using a convolution kernel 7x5 for X and 5x7 for Y. Result is nearly the same than Canny Deriche but process is much faster.
• Gaussian: It performs a convolution with the derivatives of a Gaussian function along each image axis.
• Sobel: It performs a convolution with the Sobel Kernel.
• Prewitt: It performs a convolution with the Prewitt Kernel.

See also:

SoRadialGradientCenteredProcessing2d, SoMorphologicalGradientProcessing.

File format/default:

GradientOperatorProcessing2d {

inImage	NULL
gradientOperator	CANNY_DERICHE
gradientMode	AMPLITUDE_MAX_OF_MAGS
standardDeviation	60.0f

}

Library references: gradient

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SoGradientOperatorProcessing2d.GradientModes
static class	SoGradientOperatorProcessing2d.GradientOperators

Nested classes/interfaces inherited from class com.openinventor.imageviz.engines.SoImageVizEngine

SoImageVizEngine.ComputeModes, SoImageVizEngine.EventArg, SoImageVizEngine.Neighborhood3ds

Nested classes/interfaces inherited from class com.openinventor.inventor.Inventor

Inventor.ConstructorCommand

Field Summary

Fields

Modifier and Type	Field and Description
SoSFEnum<SoGradientOperatorProcessing2d.GradientModes>	gradientMode Select an output mode.
SoSFEnum<SoGradientOperatorProcessing2d.GradientOperators>	gradientOperator Select the gradient operator.
SoSFImageDataAdapter	inImage The input image.
SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter>	outAmplitudeImage The output gradient amplitude image.
SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter>	outGradientXImage The output X-gradient image.
SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter>	outGradientYImage The output Y-gradient image.
SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter>	outOrientationImage The output gradient orientation image.
SoSFFloat	standardDeviation The standard deviation.

Fields inherited from class com.openinventor.imageviz.engines.SoImageVizEngine

onBegin, onEnd, onProgress

Fields inherited from class com.openinventor.inventor.Inventor

VERBOSE_LEVEL, ZeroHandle

Constructor Summary

Constructors

Constructor and Description
SoGradientOperatorProcessing2d() Constructor.

Method Summary

Methods inherited from class com.openinventor.imageviz.engines.SoImageVizEngine

abortEvaluate, isEvaluating, startEvaluate, waitEvaluate

Methods inherited from class com.openinventor.inventor.engines.SoEngine

copy, getByName, getOutput, getOutputName

Methods inherited from class com.openinventor.inventor.fields.SoFieldContainer

copyFieldValues, copyFieldValues, enableNotify, fieldsAreEqual, get, getAllFields, getEventIn, getEventOut, getField, getFieldName, hasDefaultValues, isNotifyEnabled, set, setToDefaults

Methods inherited from class com.openinventor.inventor.misc.SoBase

dispose, getName, isDisposable, isSynchronizable, setName, setSynchronizable, touch

Methods inherited from class com.openinventor.inventor.Inventor

getNativeResourceHandle

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

inImage

public final SoSFImageDataAdapter inImage

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

gradientOperator

public final SoSFEnum<SoGradientOperatorProcessing2d.GradientOperators> gradientOperator

Select the gradient operator. . Default is CANNY_DERICHE

gradientMode

public final SoSFEnum<SoGradientOperatorProcessing2d.GradientModes> gradientMode

Select an output mode. . Default is AMPLITUDE_MAX_OF_MAGS

standardDeviation

public final SoSFFloat standardDeviation

The standard deviation. Default value is 60.0f.

outGradientXImage

public final SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter> outGradientXImage

The output X-gradient image. Default value is NULL. Supported types include: grayscale binary label color image.

outGradientYImage

public final SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter> outGradientYImage

The output Y-gradient image. Default value is NULL. Supported types include: grayscale binary label color image.

outAmplitudeImage

public final SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter> outAmplitudeImage

The output gradient amplitude image. Default value is NULL. Supported types include: grayscale binary label color image.

outOrientationImage

public final SoImageVizEngineOutput<SoSFImageDataAdapter,SoImageDataAdapter> outOrientationImage

The output gradient orientation image. Default value is NULL. Supported types include: grayscale binary label color image.

Constructor Detail

SoGradientOperatorProcessing2d

public SoGradientOperatorProcessing2d()

Constructor.