/*
* CannyHoriz.java
*
* Created on August 27, 2006, 4:32, PM
*
* To change this templatef, choose Tools | Template Manager
* and open the template in the editor.
*
* Copyright 2007 by Jon A. Webb
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the Lesser GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package jjil.algorithm;
import jjil.core.Error;
import jjil.core.Gray8Image;
import jjil.core.Image;
import jjil.core.PipelineStage;
/**
* Computes a simple horizontal edge measure. The measure is simply the difference
* between the current pixel and the one to the left, clamped between Byte.MIN_VALUE
* and Byte.MAX_VALUE. The output replaces the input.
* @author webb
*/
public class Gray8HorizSimpleEdge extends PipelineStage {
/** Creates a new instance of Gray8HorizSimpleEdge
*/
public Gray8HorizSimpleEdge() {
}
/** Compute a simple horizontal edge measure. The measure is simply the difference
* between the current pixel and the one to the left, clamped between Byte.MIN_VALUE
* and Byte.MAX_VALUE. The output replaces the input.
*
* @param image the input Gray8Image
* @throws jjil.core.Error if image is not a Gray8Image
*/
public void push(Image image) throws jjil.core.Error {
if (!(image instanceof Gray8Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY8IMAGE,
image.toString(),
null,
null);
}
Gray8Image input = (Gray8Image) image;
byte[] bIn = input.getData();
int cWidth = input.getWidth();
for (int i=0; i<input.getHeight(); i++) {
int nPrev;
int nThis = bIn[i*cWidth];
for (int j=0; j<cWidth; j++) {
nPrev = nThis;
nThis = bIn[i*cWidth + j];
int nVal = Math.max(Byte.MIN_VALUE,
Math.min(Byte.MAX_VALUE, nPrev - nThis));
bIn[i*cWidth + j] = (byte) nVal;
}
}
super.setOutput(input);
}
}