001/** 002 * Copyright (c) 2011, The University of Southampton and the individual contributors. 003 * All rights reserved. 004 * 005 * Redistribution and use in source and binary forms, with or without modification, 006 * are permitted provided that the following conditions are met: 007 * 008 * * Redistributions of source code must retain the above copyright notice, 009 * this list of conditions and the following disclaimer. 010 * 011 * * Redistributions in binary form must reproduce the above copyright notice, 012 * this list of conditions and the following disclaimer in the documentation 013 * and/or other materials provided with the distribution. 014 * 015 * * Neither the name of the University of Southampton nor the names of its 016 * contributors may be used to endorse or promote products derived from this 017 * software without specific prior written permission. 018 * 019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 029 */ 030package org.openimaj.image.processing.resize.filters; 031 032import org.openimaj.image.processing.resize.ResizeFilterFunction; 033 034/** 035 * Mitchell filter for the resample function. 036 * 037 * @author David Dupplaw (dpd@ecs.soton.ac.uk) 038 * 039 */ 040public class MitchellFilter implements ResizeFilterFunction 041{ 042 /** 043 * The singleton instance of the filter 044 */ 045 public static ResizeFilterFunction INSTANCE = new MitchellFilter(); 046 047 /** 048 * Returns the defaultSupport 049 * 050 * @return the defaultSupport 051 */ 052 @Override 053 public double getSupport() 054 { 055 return 2; 056 } 057 058 /** 059 * @see ResizeFilterFunction#filter(double) 060 */ 061 @Override 062 public double filter(double t) 063 { 064 double B, C; 065 B = C = 1d / 3d; 066 067 double tt; 068 069 tt = t * t; 070 if (t < 0) 071 t = -t; 072 if (t < 1.0) 073 { 074 t = (((12.0 - 9.0 * B - 6.0 * C) * (t * tt)) + ((-18.0 + 12.0 * B + 6.0 * C) * tt) + (6.0 - 2 * B)); 075 return (t / 6.0); 076 } 077 else if (t < 2.0) 078 { 079 t = (((-1.0 * B - 6.0 * C) * (t * tt)) + ((6.0 * B + 30.0 * C) * tt) + ((-12.0 * B - 48.0 * C) * t) + (8.0 * B + 24 * C)); 080 return (t / 6.0); 081 } 082 return (0.0); 083 } 084}