// Catalano Imaging Library
// The Catalano Framework
//
// Copyright © Diego Catalano, 2012-2016
// diego.catalano at live.com
//
//    This library 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 2.1 of the License, or (at your option) any later version.
//
//    This library 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 GNU Lesser General Public
//    License along with this library; if not, write to the Free Software
//    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
//
package Catalano.Imaging.Tools;

/**
 * Kernels for convolution filter.
 * @author Diego Catalano
 */
public final class ConvolutionKernel{

    /**
     * Don't let anyone instantiate this class.
     */
    private ConvolutionKernel() {}

    /**
     * -1 -1 -1
     * 
-1 8 -1
     * 
-1 -1 -1
     */
    public static int[][] Laplacian = {
        {-1, -1, -1},
        {-1, 8, -1},
        {-1, -1, -1}};

    /**
     * -1 0 1
     * 
-2 0 2
     * 
-1 0 -1
     */
    public static int[][] SobelVertical = {
        {-1, 0, 1},
        {-2, 0, 2},
        {-1, 0, 1}};

    /**
     * -1 -2 -1
     * 
0 0 0
     * 
1 2 1
     */
    public static int[][] SobelHorizontal = {
        {-1, -2, -1},
        {0, 0, 0},
        {1, 2, 1}};
    
    /**
     * -1 0 1
     * 
0 0 0
     * 
1 0 -1
     */
    public static int[][] SobelCross3x3 = {
        {-1, 0, 1},
        {0, 0, 0},
        {1, 0, -1}};
    
    /**
     * -1 -2 0 2 1
     * 
-2 -4 0 4 0
     * 
0 0 0 0 0
     * 
2 4 0 -4 -2
     * 
1 2 0 -2 -1
     */
    public static int[][] SobelCross5x5 = {
        {-1, -2, 0, 2, 1},
        {-2, -4, 0, 4, 0},
        {0, 0, 0, 0, 0},
        {2, 4, 0, -4, -2},
        {1, 2, 0, -2, -1}};
    
    /**
     * 1 2 1
     * 
-2 -4 -2
     * 
1 2 1
     */
    public static int[][] SobelHorizontalSD3x3 = {
        {1, 2, 1},
        {-2, -4, -2},
        {1, 2, 1}};
    
    /**
     * 1 4 6 4 1
     * 
0 0 0 0 0
     * 
-2 -8 -12 -8 -2
     * 
0 0 0 0 0
     * 
1 4 6 4 1
     */
    public static int[][] SobelHorizontalSD5x5 = {
        {1, 4, 6, 4, 1},
        {0, 0, 0, 0, 0},
        {-2, -8, -12, -8, -2},
        {0, 0, 0, 0, 0},
        {1, 4, 6, 4, 1}};
    
    /**
     * 1 -2 1
     * 
2 -4 2
     * 
1 -2 1
     */
    public static int[][] SobelVerticalSD3x3 = {
        {1, -2, 1},
        {2, -4, 2},
        {1, -2, 1}};
    
    /**
     * 1 0 -2 0 1
     * 
4 0 -8 0 4
     * 
6 0 -12 0 6
     * 
4 0 -8 0 4
     * 
1 0 -2 0 1
     */
    public static int[][] SobelVerticalSD5x5 = {
        {1, 0, -2, 0, 1},
        {4, 0, -8, 0, 4},
        {6, 0, -12, 0, 6},
        {4, 0, -8, 0, 4},
        {1, 0, -2, 0, 1}};

    /**
     * 1 0 -1
     * 
1 0 -1
     * 
1 0 -1
     */
    public static int[][] PrewittHorizontal = {
        {1, 0, -1},
        {1, 0, -1},
        {1, 0, -1 }};

    /**
     * 1 1 1
     * 
0 0 0
     * 
-1 -1 -1
     */
    public static int[][] PrewittVertical= {
        {1, 1, 1},
        {0, 0, 0},
        {-1, -1, -1 }};

    /**
     * 1 0
     * 
0 -1
     */
    public static int[][] RobertsHorizontal = {
        {1,0},
        {0,-1}};

    /**
     * 0 1
     * 
-1 0
     */
    public static int[][] RobertsVertical = {
        {0,1},
        {-1,0}};
    
    /**
     * 3 10 3
     * 
0 0 0
     * 
-3 -10 -3
     */
    public static int[][] ScharrHorizontal = {
        {3, 10, 3},
        {0, 0, 0},
        {-3, -10, -3}};
    
    /**
     * 3 0 -3
     * 
10 0 -10
     * 
3 0 -3
     */
    public static int[][] ScharrVertical = {
        {3, 0, -3},
        {10, 0, -10},
        {3, 0, -3}};
    
    /**
     * 0 0 -1 0 0
     * 
0 -1 -2 -1 0
     * 
-1 -2 16 -2 -1
     * 
0 -1 -2 -1 0
     * 
0 0 -1 0 0
     */
    public static int[][] LaplacianOfGaussian = {
        {0, 0, -1, 0, 0},
        {0, -1, -2, -1, 0},
        {-1, -2, 16, -2, -1},
        {0, -1, -2, -1, 0},
        {0, 0, -1, 0, 0}};
    
    /**
     * Smooth Noise Robust (Horizontal).
     * This mask use 1/32 conv(mask) as weight.
     * Combines isotropic noise suppression and precise gradient estimation.
     * References: http://www.holoborodko.com/pavel/image-processing/edge-detection/
     */
    public static int[][] SmoothNoiseRobust_Horizontal = {
        {-1, -2, -1},
        {-2, -4, -2},
        {0, 0, 0},
        {2, 4, 2},
        {1, 2, 1}};
    
    /**
     * Smooth Noise Robust (Vertical).
     * This mask use 1/32 conv(mask) as weight.
     * Combines isotropic noise suppression and precise gradient estimation.
     * References: http://www.holoborodko.com/pavel/image-processing/edge-detection/
     */
    public static int[][] SmoothNoiseRobust_Vertical = {
        {-1, -2, 0, 2, 1},
        {-2, -4, 0, 4, 2},
        {-1, -2, 0, 2, 1}};
}