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1 #include "dwt_util.h"
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2 #include "wang_common.h"
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3
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4 void init_subbands(Image_tree tree) {
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5 int levels = 0;
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6 int i;
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7 Image_tree p = tree;
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8
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9 // determine # of detail subbands
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10 while (p->coarse != NULL) {
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11 levels++;
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12 p = p->coarse;
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13 }
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14
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15 // there are 3 detail subbands per level
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16 n_subbands = 3 * levels;
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17
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18 // allocate memory for subband data
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19 subbands = malloc(n_subbands * sizeof(Subband_data));
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20
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21 p = tree;
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22 i = 0;
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23 while (p->coarse != NULL) {
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24 subbands[i++] = alloc_subband(HORIZONTAL, p->horizontal);
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25 subbands[i++] = alloc_subband(VERTICAL, p->vertical);
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26 subbands[i++] = alloc_subband(DIAGONAL, p->diagonal);
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27
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28 p = p->coarse;
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29 }
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30
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31 }
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32
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33 Subband_data alloc_subband(int type, Image_tree tree) {
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34 int i;
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35 Subband_data p = malloc(sizeof(struct Subband_data_struct));
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36
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37 p->T = 0.0;
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38 p->beta = 0.0;
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39 p->Cmax = 0.0;
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40 p->tree = tree;
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41 p->level = tree->level;
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42 p->width = tree->image->width;
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43 p->height = tree->image->height;
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44 p->size = p->height * p->width;
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45 p->image = tree->image;
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46 p->type = type;
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47
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48 p->selected = malloc(p->height * sizeof(char *));
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49 p->selected[0] = calloc(p->size, sizeof(char));
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50 for (i = 1; i < p->height; i++)
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51 p->selected[i] = &(p->selected[0][i * p->width]);
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52
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53 return p;
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54 }
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55
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56 void set_subband_beta(Subband_data subband, double beta) {
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57 subband->beta = beta;
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58 }
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59
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60 void set_subbands_beta(double beta) {
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61 int i;
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62
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63 for (i = 0; i < n_subbands; i++)
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64 set_subband_beta(subbands[i], beta);
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65 }
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66
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67 void set_subbands_type_beta(int type, double beta) {
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68 int i;
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69
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70 for (i = 0; i < n_subbands; i++)
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71 if (subbands[i]->type == type)
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72 set_subband_beta(subbands[i], beta);
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73 }
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74
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75 void calc_subband_threshold(Subband_data subband) {
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76 double max;
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77 int i, j;
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78
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79 max = fabs(get_pixel(subband->image, 0, 0));
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80 for (i = 0; i < subband->height; i++)
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81 for (j = 0; j < subband->width; j++) {
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82 Pixel p = fabs(get_pixel(subband->image, i, j));
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83 if (p > max)
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84 max = p;
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85 }
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86
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87 subband->Cmax = max;
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88 subband->T = max / 2.0;
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89 }
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90
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91 void calc_subbands_threshold() {
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92 int i;
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93
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94 for (i = 0; i < n_subbands; i++)
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95 calc_subband_threshold(subbands[i]);
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96 }
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97
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98 Subband_data select_subband() {
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99 int max = 0;
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100 int i;
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101
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102 for (i = 0; i < n_subbands; i++)
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103 if ((subbands[i]->beta * subbands[i]->T) > (subbands[max]->beta * subbands[max]->T))
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104 max = i;
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105
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106 return subbands[max];
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107 }
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108
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109 int subband_coeff_isselected(Subband_data subband, int coeff) {
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110 return subband->selected[0][coeff];
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111 }
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112
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113 Pixel get_subband_coeff(Subband_data subband, int coeff) {
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114 return subband->image->data[coeff];
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115 }
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116
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117 void set_subband_coeff(Subband_data subband, int coeff, Pixel data) {
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118 subband->image->data[coeff] = data;
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119 }
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120
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121 int select_subband_coeff_from(Subband_data subband, int from) {
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122 int i;
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123
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124 for (i = from; i < subband->size; i++)
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125 if (!subband_coeff_isselected(subband, i) &&
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126 get_subband_coeff(subband, i) > subband->T)
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127 return i;
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128
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129 return -1;
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130 }
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131
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132 int select_subband_coeff(Subband_data subband) {
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133 return select_subband_coeff_from(subband, 0);
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0
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134 }
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135
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136 void mark_subband_coeff(Subband_data subband, int coeff) {
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137 subband->selected[0][coeff] = 1;
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138 }
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139
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140 void free_subband(Subband_data subband) {
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141 free(subband->selected[0]);
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142 free(subband->selected);
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143 free(subband);
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144 }
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145
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146 void free_subbands() {
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147 int i;
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148
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149 for (i = 0; i < n_subbands; i++)
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150 free_subband(subbands[i]);
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151
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152 free(subbands);
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153 }
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154
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155 #define LARGE DBL_MAX
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156
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157 Pixel figure_orig_coeff(double T, double alpha, double beta, Pixel coeff) {
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158 int p, p_min = 0;
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159 double dist_min = LARGE;
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160 double sign = (coeff >= 0) ? 1.0 : -1.0;
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161
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162 for (p = 1; p < 1.0 / (2.0 * alpha); p++) {
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163 double dist, delta;
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164
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165 delta = (1.0 + 2.0 * p * alpha) * T;
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166 dist = fabs(delta - fabs(coeff));
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167
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168 if (dist < dist_min) {
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169 dist_min = dist;
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170 p_min = p;
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171 }
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172 }
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173
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174 if (!p_min) p_min = 1;
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175 return sign * (1.0 + 2.0 * p_min * alpha) * T;
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176 }
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