/*
* $RCSfile: ErodeDescriptor.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:57:35 $
* $State: Exp $
*/
package com.lightcrafts.mediax.jai.operator;
import com.lightcrafts.media.jai.util.AreaOpPropertyGenerator;
import java.awt.RenderingHints;
import java.awt.image.RenderedImage;
import com.lightcrafts.mediax.jai.JAI;
import com.lightcrafts.mediax.jai.KernelJAI;
import com.lightcrafts.mediax.jai.OperationDescriptorImpl;
import com.lightcrafts.mediax.jai.ParameterBlockJAI;
import com.lightcrafts.mediax.jai.PropertyGenerator;
import com.lightcrafts.mediax.jai.RenderedOp;
import com.lightcrafts.mediax.jai.registry.RenderedRegistryMode;
/**
*
* An <code>OperationDescriptor</code> describing the "Erode" operation.
*
* <p> <b>Gray Scale Erosion</b>
* is a spatial operation that computes
* each output sample by subtracting elements of a kernel from the samples
* surrounding a particular source sample.
* The mathematical formulation for erosion operation is:
*
* <p> For a kernel K with a key position (xKey, yKey), the erosion
* of image I at (x,y) is given by:
* <pre>
* max{ f: f + K(xKey+i, yKey+j) <= I(x+i,y+j): all (i,j)}
*
* "all" possible (i,j) means that both I(x+i,y+j) and K(xKey+i, yKey+j)
* are in bounds. Otherwise, the value is set to 0.
* "f" represents all possible floats satisfying the restriction.
*
* </pre>
* <p> Intuitively, the kernel is like an unbrella and the key point
* is the handle. At every point, you try to push the umbrella up as high
* as possible but still underneath the image surface. The final height
* of the handle is the value after erosion. Thus if you want the image
* to erode from the upper right to bottom left, the following would do.
*
* <p><center>
* <table border=1>
* <tr align=center><td>0</td><td>0</td><td>X</td> </tr>
* <tr align=center><td>0</td><td>X</td><td>0</td> </tr>
* <tr align=center><td><b>X</b></td><td>0</td><td>0</td> </tr>
* </table></center>
*
* <p> Note that even if every entry of a kernel is zero,
* the erosion changes the image. Different key positions
* will also lead to different erosion results for such zero kernels.
*
* <p> Pseudo code for the erosion operation is as follows.
* Assuming the kernel K is of size M rows x N cols
* and the key position is (xKey, yKey).
*
* <pre>
*
* // erosion
* for every dst pixel location (x,y){
* tmp = infinity;
* for (i = -xKey; i < M - xKey; i++){
* for (j = -yKey; j < N - yKey; j++){
* if((x+i, y+j) are in bounds of src){
* tmp = min{tmp, src[x + i][y + j] - K[xKey + i][yKey + j]};
* }
* }
* }
* dst[x][y] = tmp;
* if (dst[x][y] == infinity)
* dst[x][y] = 0;
* }
* </pre>
*
* <p> The kernel cannot be bigger in any dimension than the image data.
*
* <p> <b>Binary Image Erosion</b>
* requires the kernel to be binary, that is, to have values 0 and 1
* for each kernel entry.
* Intuitively, binary erosion slides the kernel
* key position and place it at every point (x,y) in the src image.
* The dst value at this position is set to 1 if the entire kernel lies
* within the image bounds and the src image value is 1
* wherever the corresponding kernel value is 1."
* Otherwise, the value after erosion at (x,y) is set to 0.
* Erosion usually shrinks images, but it can fill holes
* with kernels like
* <pre> [1 0 1] </pre>
* and the key position at the center.
*
* <p> Pseudo code for the binary erosion operation is as follows.
*
* <pre>
* // erosion
* for every dst pixel location (x,y){
* dst[x][y] = 1;
* for (i = -xKey; i < M - xKey; i++){
* for (j = -yKey; j < N - yKey; j++){
* if((x+i,y+j) is out of bounds of src ||
* src(x+i, y+j)==0 && Key(xKey+i, yKey+j)==1){
* dst[x][y] = 0; break;
* }
* }
* }
* }
*
* The following can be used as references for the underlying
* connection between these two algorithms.
*
* <p> Reference: An Introduction to Nonlinear Image Processing,
* by Edward R. Bougherty and Jaakko Astola,
* Spie Optical Engineering Press, 1994.
*
* It should be noted that this operation automatically adds a
* value of <code>Boolean.TRUE</code> for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> to the given
* <code>configuration</code> so that the operation is performed
* on the pixel values instead of being performed on the indices into
* the color map if the source(s) have an <code>IndexColorModel</code>.
* This addition will take place only if a value for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> has not already been
* provided by the user. Note that the <code>configuration</code> Map
* is cloned before the new hint is added to it. The operation can be
* smart about the value of the <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code>
* <code>RenderingHints</code>, i.e. while the default value for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> is
* <code>Boolean.TRUE</code>, in some cases the operator could set the
* default.
*
* <p><table border=1>
* <caption>Resource List</caption>
* <tr><th>Name</th> <th>Value</th></tr>
* <tr><td>GlobalName</td> <td>Erode</td></tr>
* <tr><td>LocalName</td> <td>Erode</td></tr>
* <tr><td>Vendor</td> <td>com.lightcrafts.media.jai</td></tr>
* <tr><td>Description</td> <td>Performs kernel based Erode on
* an image.</td></tr>
* <tr><td>DocURL</td> <td>http://java.sun.com/products/java-media/jai/forD
evelopers/jai-apidocs/javax/media/jai/operator/ErodeDescriptor.html</td
></tr>
* <tr><td>Version</td> <td>1.1</td></tr>
* <tr><td>arg0Desc</td> <td>The erode kernel.</td></tr>
* </table></p>
*
* <p><table border=1>
* <caption>Parameter List</caption>
* <tr><th>Name</th> <th>Class Type</th>
* <th>Default Value</th></tr>
* <tr><td>kernel</td> <td>com.lightcrafts.mediax.jai.KernelJAI</td>
* <td>NO_PARAMETER_DEFAULT</td>
* </table></p>
*
* </pre>
*
*
* @see com.lightcrafts.mediax.jai.KernelJAI
*
* @since JAI 1.1
*/
public class ErodeDescriptor extends OperationDescriptorImpl {
/**
* The resource strings that provide the general documentation and
* specify the parameter list for a Erode operation.
*/
private static final String[][] resources = {
{"GlobalName", "Erode"},
{"LocalName", "Erode"},
{"Vendor", "com.lightcrafts.media.jai"},
{"Description", JaiI18N.getString("ErodeDescriptor0")},
{"DocURL", "http://java.sun.com/products/java-media/jai/forDevelopers/jaiapi/<br>com.lightcrafts.mediax.jai.operator.ErodeDescriptor.html"},
{"Version", JaiI18N.getString("DescriptorVersion")},
{"arg0Desc", JaiI18N.getString("ErodeDescriptor1")}
};
/** The parameter names for the Erode operation. */
private static final String[] paramNames = {
"kernel"
};
/** The parameter class types for the Erode operation. */
private static final Class[] paramClasses = {
com.lightcrafts.mediax.jai.KernelJAI.class
};
/** The parameter default values for the Erode operation. */
private static final Object[] paramDefaults = {
NO_PARAMETER_DEFAULT
};
/** Constructor. */
public ErodeDescriptor() {
super(resources, 1, paramClasses, paramNames, paramDefaults);
}
/**
* Returns an array of <code>PropertyGenerators</code> implementing
* property inheritance for the "Erode" operation.
*
* @return An array of property generators.
*/
public PropertyGenerator[] getPropertyGenerators() {
PropertyGenerator[] pg = new PropertyGenerator[1];
pg[0] = new AreaOpPropertyGenerator();
return pg;
}
/**
* Performs binary kernel based Erode operation on the image.
*
* <p>Creates a <code>ParameterBlockJAI</code> from all
* supplied arguments except <code>hints</code> and invokes
* {@link JAI#create(String,ParameterBlock,RenderingHints)}.
*
* @see JAI
* @see ParameterBlockJAI
* @see RenderedOp
*
* @param source0 <code>RenderedImage</code> source 0.
* @param kernel The binary convolution kernel.
* @param hints The <code>RenderingHints</code> to use.
* May be <code>null</code>.
* @return The <code>RenderedOp</code> destination.
* @throws IllegalArgumentException if <code>source0</code> is <code>null</code>.
* @throws IllegalArgumentException if <code>kernel</code> is <code>null</code>.
*/
public static RenderedOp create(RenderedImage source0,
KernelJAI kernel,
RenderingHints hints) {
ParameterBlockJAI pb =
new ParameterBlockJAI("Erode",
RenderedRegistryMode.MODE_NAME);
pb.setSource("source0", source0);
pb.setParameter("kernel", kernel);
return JAI.create("Erode", pb, hints);
}
}