com.github.ojil.algorithm.PsfGray8 Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of ojil-core Show documentation
Open Java Imaging Library.
There is a newer version: 0.0.11
/*
 * PsfGray8.java
 *
 * Created on November 3, 2007, 2:58 PM
 *
 * 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 .
 *
 */

package com.github.ojil.algorithm;

import com.github.ojil.core.Gray8Image;

/**
 * Provides point spread functions for use in inverse filtering.
 * 
 * @author webb
 */
public class PsfGray8 {
    
    /**
     * Computes a horizontal bar point spread function, with a given width. This
     * corresponds to a horizontal blur. The output image is scaled so the sum
     * of all values is 256.
     * 
     * @param nImageWidth
     *            The image width of the image to create. The image is always
     *            square so this is also the height.
     * @param nBarHalfWidth
     *            The width of the bar, divided by 2 and rounded down. The
     *            actual width is twice this width plus 1, centered on the
     *            center of the image.
     * @return A Gray8Image that can be passed to InverseFilter to remove
     *         horizontal blur.
     */
    public static Gray8Image horizBar(final int nImageWidth, final int nBarHalfWidth) {
        final Gray8Image imResult = new Gray8Image<>(nImageWidth, nImageWidth, Byte.MIN_VALUE);
        final Byte[] bData = imResult.getData();
        final int nC = nImageWidth / 2;
        final int nArea = (2 * nBarHalfWidth) + 1;
        final int nRow = nC * nImageWidth;
        for (int j = -nBarHalfWidth; j <= nBarHalfWidth; j++) {
            bData[nRow + nC + j] = (byte) (Byte.MAX_VALUE / nArea);
        }
        return imResult;
    }
    
    /**
     * Computes a disk-shaped point spread function that can be used to do
     * deblurring for circular blur. The output image is scaled so the sum of
     * the values is 256.
     * 
     * @param nImageWidth
     *            The output image width. The image is always square so this is
     *            also the height.
     * @param nRadius
     *            The radius of the disk.
     * @return A Gray8Image that can be passed to InverseFilter to remove
     *         circular blur, for example that due to defocus.
     */
    public static Gray8Image disk(final int nImageWidth, final int nRadius) {
        final Gray8Image imResult = new Gray8Image<>(nImageWidth, nImageWidth, Byte.MIN_VALUE);
        final Byte[] bData = imResult.getData();
        final int nC = nImageWidth / 2;
        final int nRadiusSq = nRadius * nRadius;
        int nArea = 0;
        // compute area of the disk. The rounding is tricky so I decided
        // to just count.
        for (int i = -nRadius; i <= nRadius; i++) {
            for (int j = -nRadius; j <= nRadius; j++) {
                if (((i * i) + (j * j)) <= nRadiusSq) {
                    nArea++;
                }
            }
        }
        for (int i = -nRadius; i <= nRadius; i++) {
            final int nRow = (nC + i) * nImageWidth;
            for (int j = -nRadius; j <= nRadius; j++) {
                if (((i * i) + (j * j)) <= nRadiusSq) {
                    bData[nRow + nC + j] = (byte) (Byte.MAX_VALUE / nArea);
                }
            }
        }
        return imResult;
    }
}