jaitools.media.jai.regionalize
Class RegionalizeDescriptor

java.lang.Object
  javax.media.jai.OperationDescriptorImpl
      jaitools.media.jai.regionalize.RegionalizeDescriptor

All Implemented Interfaces:

Serializable, javax.media.jai.OperationDescriptor, javax.media.jai.RegistryElementDescriptor

public class RegionalizeDescriptor
extends javax.media.jai.OperationDescriptorImpl

Describes the "Regionalize" operation.

This operation takes a single source image and identifies regions of connected pixels with uniform value, where value comparisons take into account a user-specified tolerance.

Note: At present, this operator only deals with a single band.

Algorithm

The operator scans the source image left to right, top to bottom. When it reaches a pixel that has not been allocated to a region yet it uses that pixel as the starting point for a flood-fill search (similar to flood-filling in a paint program). The value of the starting pixel is recorded as the reference value for the new region. The search works its way outwards from the starting pixel, testing other pixels for inclusion in the region. A pixel will be included if:

      |value - reference value| <= tolerance 

where tolerance is a user-specified parameter.

If the diagonal parameter is set to true, the flood-fill search will include pixels that can only be reached via a diagonal step; if false, only orthogonal steps are taken.

The search continues until no further pixels can be added to the region. The region is then allocated a unique integer ID and summary statistics (bounds, number of pixels, reference value) are recorded for it.

The output of the operation is an image of data type TYPE_INT, where each pixel's value is its region ID. A RegionData object can be retrieved as a property of the output image using the property name REGION_DATA_PROPERTY).

Example

 RenderedImage myImg = ...

 ParameterBlockJAI pb = new ParameterBlockJAI("regionalize");
 pb.setSource("source0", myImg);
 pb.setParameter("band", 0);
 pb.setParameter("tolerance", 0.1d);
 pb.setParameter("diagonal", false);
 RenderedOp regionImg = JAI.create("Regionalize", pb);

 // have a look at the image (this will force rendering and
 // the calculation of region data)
 jaitools.utils.ImageFrame frame = new jaitools.utils.ImageFrame();
 frame.displayImage(op, "Regions");

 // print the summary data
 RegionData regData =
    (RegionData)op.getProperty(RegionalizeDescriptor.REGION_DATA_PROPERTY);

 List<Region> regions = regData.getData();
 Iterator<Region> iter = regions.iterator();
 System.out.println("ID\tValue\tSize\tMin X\tMax X\tMin Y\tMax Y");
 while (iter.hasNext()) {
     Region r = iter.next();
     System.out.println( String.format("%d\t%.2f\t%d\t%d\t%d\t%d\t%d",
         r.getId(),
         r.getRefValue(),
         r.getNumPixels(),
         r.getMinX(),
         r.getMaxX(),
         r.getMinY(),
         r.getMaxY() ));
 

Parameters

Name	Type	Default value
band	int	0
tolerance	double	0d
diagonal	boolean	false

Since:

1.0

Version:

$Id: RegionalizeDescriptor.java 1383 2011-02-10 11:22:29Z michael.bedward $

Author:

Michael Bedward

See Also:

Serialized Form

Field Summary

static String

REGION_DATA_PROPERTY The propoerty name to retrieve the RegionData object which holds summary data for regions identified in the source image and depicted in the destination image

Fields inherited from class javax.media.jai.OperationDescriptorImpl

resources, sourceNames, supportedModes

Fields inherited from interface javax.media.jai.OperationDescriptor

NO_PARAMETER_DEFAULT

Constructor Summary

RegionalizeDescriptor()
Constructor.

Method Summary

boolean	arePropertiesSupported()
static javax.media.jai.RenderedOp	create(RenderedImage source0, int band, double tolerance, boolean diagonal, RenderingHints hints) Convenience method which constructs a ParameterBlockJAI and invokes JAI.create("regionalize", params) .

Methods inherited from class javax.media.jai.OperationDescriptorImpl

getDefaultSourceClass, getDestClass, getDestClass, getInvalidRegion, getName, getNumParameters, getNumSources, getParamClasses, getParamDefaults, getParamDefaultValue, getParameterListDescriptor, getParamMaxValue, getParamMinValue, getParamNames, getPropertyGenerators, getPropertyGenerators, getRenderableDestClass, getRenderableSourceClasses, getResourceBundle, getResources, getSourceClasses, getSourceClasses, getSourceNames, getSupportedModes, isImmediate, isModeSupported, isRenderableSupported, isRenderedSupported, makeDefaultSourceClassList, validateArguments, validateArguments, validateParameters, validateParameters, validateRenderableArguments, validateRenderableSources, validateSources, validateSources

Methods inherited from class java.lang.Object

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

Field Detail

REGION_DATA_PROPERTY

public static final String REGION_DATA_PROPERTY

The propoerty name to retrieve the RegionData object which holds summary data for regions identified in the source image and depicted in the destination image

See Also:

Constant Field Values

Constructor Detail

RegionalizeDescriptor

public RegionalizeDescriptor()

Constructor.

Method Detail

arePropertiesSupported

public boolean arePropertiesSupported()

Specified by:

arePropertiesSupported in interface javax.media.jai.RegistryElementDescriptor

Overrides:

arePropertiesSupported in class javax.media.jai.OperationDescriptorImpl

create

public static javax.media.jai.RenderedOp create(RenderedImage source0,
                                                int band,
                                                double tolerance,
                                                boolean diagonal,
                                                RenderingHints hints)

Convenience method which constructs a ParameterBlockJAI and invokes JAI.create("regionalize", params) . If an ImageLayout object is included in the RenderingHints passed to this method, any specification of the SampleModel for the destination image will be overridden such that the destination will always be TYPE_INT.

Parameters:

source0 - the image to be regionalized

band - the band to process

tolerance - tolerance for pixel value comparisons

diagonal - true to include diagonal connections; false for only orthogonal connections

hints - rendering hints (may be null)

Returns:

the RenderedOp destination