/*
* Gray8LinComb.java
* Forms the linear combination of two gray images
*
* Created on September 9, 2006, 10:25 AM
*
* To change this template, 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.Ladder;
/**
* Computes linear combination of two Gray8Images. Result is
* (a*first image + b*second image) / c. The signed image values are shifted so
* the minimum value is 0 and the result is then shifted back to the signed
* range.<br>
* Intended to be used as a combination stage in a ladder operation.
* @author webb
*/
public class Gray8LinComb implements Ladder.Join {
private int nA;
private int nB;
private int nC;
/**
* Creates a new instance of Gray8LinComb
* @param a Multiplier for first image.
* @param b Multiplier for second image.
* @param c Divisor for linear combination.
* @throws jjil.core.Error if the divisor (c) is 0.
*/
public Gray8LinComb(int a, int b, int c) throws jjil.core.Error {
if (c == 0) {
throw new Error(
Error.PACKAGE.CORE,
jjil.core.ErrorCodes.MATH_DIVISION_ZERO,
null,
null,
null);
}
this.nA = a;
this.nB = b;
this.nC = c;
}
/**
* Computes the linear combination of the two images, forming a*the first image
* + b *the second image, all divided by c.
* @param imageFirst the first image (and output)
* @param imageSecond the second image
* @return the linear combination of the two byte images, replacing the first.
* @throws jjil.core.Error if either image is not a gray 8-bit
* image, or they are of different sizes.
*/
public Image doJoin(Image imageFirst, Image imageSecond)
throws jjil.core.Error
{
if (!(imageFirst instanceof Gray8Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY8IMAGE,
imageFirst.toString(),
null,
null);
}
if (!(imageSecond instanceof Gray8Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY8IMAGE,
imageSecond.toString(),
null,
null);
}
if (imageFirst.getWidth() != imageSecond.getWidth() ||
imageSecond.getHeight() != imageSecond.getHeight()) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_SIZES_DIFFER,
imageFirst.toString(),
imageSecond.toString(),
null);
}
Gray8Image gray1 = (Gray8Image) imageFirst;
Gray8Image gray2 = (Gray8Image) imageSecond;
byte[] data1 = gray1.getData();
byte[] data2 = gray2.getData();
for (int i=0; i<data1.length; i++) {
int nD1 = data1[i] - Byte.MIN_VALUE;
int nD2 = data2[i] - Byte.MIN_VALUE;
data1[i] = (byte) Math.min(
Byte.MAX_VALUE,
Math.max(Byte.MIN_VALUE,
((nD1 * this.nA + nD2 * this.nB) / this.nC) +
Byte.MIN_VALUE));
}
return gray1;
}
}