001/* 002 * $RCSfile: SynWTFilter.java,v $ 003 * $Revision: 1.1 $ 004 * $Date: 2005/02/11 05:02:34 $ 005 * $State: Exp $ 006 * 007 * Class: SynWTFilter 008 * 009 * Description: The abstract class for all synthesis wavelet 010 * filters. 011 * 012 * 013 * 014 * COPYRIGHT: 015 * 016 * This software module was originally developed by Raphaël Grosbois and 017 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel 018 * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David 019 * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research 020 * Centre France S.A) in the course of development of the JPEG2000 021 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This 022 * software module is an implementation of a part of the JPEG 2000 023 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio 024 * Systems AB and Canon Research Centre France S.A (collectively JJ2000 025 * Partners) agree not to assert against ISO/IEC and users of the JPEG 026 * 2000 Standard (Users) any of their rights under the copyright, not 027 * including other intellectual property rights, for this software module 028 * with respect to the usage by ISO/IEC and Users of this software module 029 * or modifications thereof for use in hardware or software products 030 * claiming conformance to the JPEG 2000 Standard. Those intending to use 031 * this software module in hardware or software products are advised that 032 * their use may infringe existing patents. The original developers of 033 * this software module, JJ2000 Partners and ISO/IEC assume no liability 034 * for use of this software module or modifications thereof. No license 035 * or right to this software module is granted for non JPEG 2000 Standard 036 * conforming products. JJ2000 Partners have full right to use this 037 * software module for his/her own purpose, assign or donate this 038 * software module to any third party and to inhibit third parties from 039 * using this software module for non JPEG 2000 Standard conforming 040 * products. This copyright notice must be included in all copies or 041 * derivative works of this software module. 042 * 043 * Copyright (c) 1999/2000 JJ2000 Partners. 044 * 045 * 046 * 047 */ 048 049 050package jj2000.j2k.wavelet.synthesis; 051 052import jj2000.j2k.wavelet.*; 053import jj2000.j2k.codestream.*; 054import jj2000.j2k.io.*; 055import jj2000.j2k.*; 056import java.io.*; 057 058/** 059 * This abstract class defines the methods of all synthesis wavelet 060 * filters. Specialized abstract classes that work on particular data 061 * types (int, float) provide more specific method calls while 062 * retaining the generality of this one. See the SynWTFilterInt 063 * and SynWTFilterFloat classes. Implementations of snythesis 064 * filters should inherit from one of those classes. 065 * 066 * <P>The length of the output signal is always the sum of the length 067 * of the low-pass and high-pass input signals. 068 * 069 * <P>All synthesis wavelet filters should follow the following conventions: 070 * 071 * <P>- The first sample of the output corresponds to the low-pass 072 * one. As a consequence, if the output signal is of odd-length then 073 * the low-pass input signal is one sample longer than the high-pass 074 * input one. Therefore, if the length of output signal is N, the 075 * low-pass input signal is of length N/2 if N is even and N/2+1/2 if 076 * N is odd, while the high-pass input signal is of length N/2 if N 077 * is even and N/2-1/2 if N is odd. 078 * 079 * <P>- The normalization of the analysis filters is 1 for the DC gain 080 * and 2 for the Nyquist gain (Type I normalization), for both 081 * reversible and non-reversible filters. The normalization of the 082 * synthesis filters should ensure prefect reconstruction according to 083 * this normalization of the analysis wavelet filters. 084 * 085 * <P>The synthetize method may seem very complicated, but is designed to 086 * minimize the amount of data copying and redundant calculations when 087 * used for block-based or line-based wavelet transform 088 * implementations, while being applicable to full-frame transforms as 089 * well. 090 * 091 * @see SynWTFilterInt 092 * 093 * @see SynWTFilterFloat 094 * */ 095public abstract class SynWTFilter implements WaveletFilter, 096 Markers { 097 098 /** 099 * Reconstructs the output signal by the synthesis filter, 100 * recomposing the low-pass and high-pass input signals in one 101 * output signal. This method performs the upsampling and 102 * fitering with the low pass first filtering convention. 103 * 104 * <P>The input low-pass (high-pass) signal resides in the lowSig 105 * array. The index of the first sample to filter (i.e. that will 106 * generate the first (second) output sample). is given by lowOff 107 * (highOff). This array must be of the same type as the one for 108 * which the particular implementation works with (which is 109 * returned by the getDataType() method). 110 * 111 * <P>The low-pass (high-pass) input signal can be interleaved 112 * with other signals in the same lowSig (highSig) array, and this 113 * is determined by the lowStep (highStep) argument. This means 114 * that the first sample of the low-pass (high-pass) input signal 115 * is lowSig[lowOff] (highSig[highOff]), the second is 116 * lowSig[lowOff+lowStep] (highSig[highOff+highStep]), the third 117 * is lowSig[lowOff+2*lowStep] (highSig[highOff+2*highStep]), and 118 * so on. Therefore if lowStep (highStep) is 1 there is no 119 * interleaving. This feature allows to filter columns of a 2-D 120 * signal, when it is stored in a line by line order in lowSig 121 * (highSig), without having to copy the data, in this case the 122 * lowStep (highStep) argument should be the line width of the 123 * low-pass (high-pass) signal. 124 * 125 * <P>The output signal is placed in the outSig array. The outOff 126 * and outStep arguments are analogous to the lowOff and lowStep 127 * ones, but they apply to the outSig array. The outSig array must 128 * be long enough to hold the low-pass output signal. 129 * 130 * @param lowSig This is the array that contains the low-pass 131 * input signal. It must be of the correct type (e.g., it must be 132 * int[] if getDataType() returns TYPE_INT). 133 * 134 * @param lowOff This is the index in lowSig of the first sample to 135 * filter. 136 * 137 * @param lowLen This is the number of samples in the low-pass 138 * input signal to filter. 139 * 140 * @param lowStep This is the step, or interleave factor, of the 141 * low-pass input signal samples in the lowSig array. See above. 142 * 143 * @param highSig This is the array that contains the high-pass 144 * input signal. It must be of the correct type (e.g., it must be 145 * int[] if getDataType() returns TYPE_INT). 146 * 147 * @param highOff This is the index in highSig of the first sample to 148 * filter. 149 * 150 * @param highLen This is the number of samples in the high-pass 151 * input signal to filter. 152 * 153 * @param highStep This is the step, or interleave factor, of the 154 * high-pass input signal samples in the highSig array. See above. 155 * 156 * @param outSig This is the array where the output signal is 157 * placed. It must be of the same type as lowSig and it should be 158 * long enough to contain the output signal. 159 * 160 * @param outOff This is the index in outSig of the element where 161 * to put the first output sample. 162 * 163 * @param outStep This is the step, or interleave factor, of the 164 * output samples in the outSig array. See above. 165 * 166 * 167 * 168 * 169 * */ 170 public abstract 171 void synthetize_lpf(Object lowSig, int lowOff, int lowLen, int lowStep, 172 Object highSig, int highOff, int highLen, int highStep, 173 Object outSig, int outOff, int outStep); 174 175 /** 176 * Reconstructs the output signal by the synthesis filter, 177 * recomposing the low-pass and high-pass input signals in one 178 * output signal. This method performs the upsampling and 179 * fitering with the high pass first filtering convention. 180 * 181 * <P>The input low-pass (high-pass) signal resides in the lowSig 182 * array. The index of the first sample to filter (i.e. that will 183 * generate the first (second) output sample). is given by lowOff 184 * (highOff). This array must be of the same type as the one for 185 * which the particular implementation works with (which is 186 * returned by the getDataType() method). 187 * 188 * <P>The low-pass (high-pass) input signal can be interleaved 189 * with other signals in the same lowSig (highSig) array, and this 190 * is determined by the lowStep (highStep) argument. This means 191 * that the first sample of the low-pass (high-pass) input signal 192 * is lowSig[lowOff] (highSig[highOff]), the second is 193 * lowSig[lowOff+lowStep] (highSig[highOff+highStep]), the third 194 * is lowSig[lowOff+2*lowStep] (highSig[highOff+2*highStep]), and 195 * so on. Therefore if lowStep (highStep) is 1 there is no 196 * interleaving. This feature allows to filter columns of a 2-D 197 * signal, when it is stored in a line by line order in lowSig 198 * (highSig), without having to copy the data, in this case the 199 * lowStep (highStep) argument should be the line width of the 200 * low-pass (high-pass) signal. 201 * 202 * <P>The output signal is placed in the outSig array. The outOff 203 * and outStep arguments are analogous to the lowOff and lowStep 204 * ones, but they apply to the outSig array. The outSig array must 205 * be long enough to hold the low-pass output signal. 206 * 207 * @param lowSig This is the array that contains the low-pass 208 * input signal. It must be of the correct type (e.g., it must be 209 * int[] if getDataType() returns TYPE_INT). 210 * 211 * @param lowOff This is the index in lowSig of the first sample to 212 * filter. 213 * 214 * @param lowLen This is the number of samples in the low-pass 215 * input signal to filter. 216 * 217 * @param lowStep This is the step, or interleave factor, of the 218 * low-pass input signal samples in the lowSig array. See above. 219 * 220 * @param highSig This is the array that contains the high-pass 221 * input signal. It must be of the correct type (e.g., it must be 222 * int[] if getDataType() returns TYPE_INT). 223 * 224 * @param highOff This is the index in highSig of the first sample to 225 * filter. 226 * 227 * @param highLen This is the number of samples in the high-pass 228 * input signal to filter. 229 * 230 * @param highStep This is the step, or interleave factor, of the 231 * high-pass input signal samples in the highSig array. See above. 232 * 233 * @param outSig This is the array where the output signal is 234 * placed. It must be of the same type as lowSig and it should be 235 * long enough to contain the output signal. 236 * 237 * @param outOff This is the index in outSig of the element where 238 * to put the first output sample. 239 * 240 * @param outStep This is the step, or interleave factor, of the 241 * output samples in the outSig array. See above. 242 * 243 * 244 * 245 * 246 * */ 247 public abstract 248 void synthetize_hpf(Object lowSig, int lowOff, int lowLen, int lowStep, 249 Object highSig, int highOff, int highLen, int highStep, 250 Object outSig, int outOff, int outStep); 251 252} 253 254