Mercurial > hg > wm
annotate Meerwald/frid2_common.c @ 21:1c4ccd635a68 v0.6
ignore *.swp
| author | Peter Meerwald-Stadler <pmeerw@pmeerw.net> |
|---|---|
| date | Sat, 28 Jan 2023 23:57:40 +0100 |
| parents | bd669312f068 |
| children |
| rev | line source |
|---|---|
| 0 | 1 #include "frid2_common.h" |
|
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
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changeset
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2 #include "signature-utils.h" |
| 0 | 3 #include "wm.h" |
| 4 | |
| 5 extern char *progname; | |
| 6 | |
| 7 void embed_low_freq(double **dcts, int cols, int rows, double alpha, int verbose) { | |
| 8 int n; | |
| 9 int row, col, dir; | |
| 10 | |
| 11 n = 0; | |
| 12 row = col = 0; | |
| 13 dir = 1; | |
| 14 while (n < nbit_signature) { | |
| 15 double d, x; | |
| 16 int embed; | |
| 17 int out; | |
| 18 | |
| 19 col -= dir; | |
| 20 row += dir; | |
| 21 if (col < 0) { dir = -1; col = 0; } | |
| 22 if (col >= cols) { dir = 1; col = cols - 1; row += 2; } | |
| 23 if (row < 0) { dir = 1; row = 0; } | |
| 24 if (row >= rows) { dir = -1; row = rows - 1; col += 2; } | |
| 25 | |
| 26 d = dcts[row][col]; | |
| 27 if (fabs(d) <= 1.0) { | |
| 28 if (verbose > 3) | |
| 29 fprintf(stderr, "%s: bit #%d - skipped (%d/%d)\n", progname, n, col, row); | |
| 30 continue; | |
| 31 } | |
| 32 | |
| 33 embed = 2 * get_signature_bit(n) - 1; | |
| 34 | |
| 35 x = (d > 0.0) ? 1.0 : -1.0; | |
| 36 out = 1; | |
| 37 while (fabs(x) < fabs(d)) { | |
| 38 x *= FORWARD_STEP(alpha); | |
| 39 out =- out; | |
| 40 } | |
| 41 | |
| 42 if (out != embed) { | |
| 43 if (fabs(d - x) < fabs(d - x * BACKWARD_STEP(alpha))) | |
| 44 x *= FORWARD_STEP(alpha); | |
| 45 else | |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
46 x *= BACKWARD_STEP(alpha); |
| 0 | 47 } |
| 48 | |
| 49 d = (x + x * BACKWARD_STEP(alpha)) / 2.0; | |
| 50 | |
| 51 if (verbose > 3) | |
| 52 fprintf(stderr, "%s: embedding bit #%d (= %d) at (%d/%d): %f -> %f\n", progname, n, get_signature_bit(n), col, row, dcts[row][col], d); | |
| 53 | |
| 54 dcts[row][col] = d; | |
| 55 | |
| 56 n++; | |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
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57 } |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
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|
58 } |
| 0 | 59 |
| 60 void embed_med_freq(double **dcts, int cols, int rows, double gamma, int seed, int verbose) { | |
| 61 // select mid-frequency (30%) coefficients | |
| 62 int start = (int) (0.35 * rows * cols + 0.5); | |
| 63 int end = (int) (0.65 * rows * cols + 0.5); | |
| 64 | |
| 65 double *vector; | |
| 66 int x = 0, y = 0, dir = 1; | |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
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67 int i, j; |
| 0 | 68 |
| 69 vector = malloc((end - start) * sizeof(double)); | |
| 70 for (i = 0; i < (end - start); i++) | |
| 71 vector[i] = 0.0; | |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
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diff
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72 |
| 0 | 73 // create pseudo-random vector |
| 74 srandom(seed); | |
| 75 for (i = 0; i < nbit_signature; i++) { | |
| 76 if (get_signature_bit(i)) | |
| 77 random(); | |
| 78 for (j = 0; j < (end - start); j++) | |
| 79 vector[j] += (double) (random() & RAND_MAX) / (double) RAND_MAX - 0.5; | |
| 80 if (!get_signature_bit(i)) | |
| 81 random(); | |
| 82 } | |
| 83 | |
| 84 for (i = 0; i < (end - start); i++) | |
| 85 vector[i] /= sqrt(nbit_signature); | |
| 86 | |
| 87 for (i = 0; i < end; i++) { | |
| 88 // zig-zag scan | |
| 89 x -= dir; | |
| 90 y += dir; | |
| 91 if (x < 0) { dir = -1; x = 0; } | |
| 92 if (x >= cols) { dir = 1; x = cols - 1; y += 2; } | |
| 93 if (y < 0) { dir = 1; y = 0; } | |
| 94 if (y >= rows) { dir = -1; y = rows - 1; x += 2; } | |
| 95 | |
| 96 // embed vector | |
| 97 if ((i - start) >= 0) { | |
| 98 // fprintf(stderr, "%d/%d: %f -> %f\n", x, y, dcts[y][x], dcts[y][x] + gamma * vector[i - start]); | |
| 99 dcts[y][x] += gamma * vector[i - start]; | |
| 100 } | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
101 } |
| 0 | 102 |
| 103 free(vector); | |
| 104 } | |
| 105 | |
| 106 double detect_low_freq(double **dcts, int cols, int rows, double alpha, double beta, int verbose) { | |
| 107 int n; | |
| 108 int row, col, dir; | |
| 109 double sum1, sum2; | |
| 110 | |
| 111 n = 0; | |
| 112 row = col = 0; | |
| 113 dir = 1; | |
| 114 sum1 = sum2 = 0.0; | |
| 115 while (n < nbit_signature1) { | |
| 116 double d, x; | |
| 117 int detect; | |
| 118 int out; | |
| 119 | |
| 120 col -= dir; | |
| 121 row += dir; | |
| 122 if (col < 0) { dir = -1; col = 0; } | |
| 123 if (col >= cols) { dir = 1; col = cols - 1; row += 2; } | |
| 124 if (row < 0) { dir = 1; row = 0; } | |
| 125 if (row >= rows) { dir = -1; row = rows - 1; col += 2; } | |
| 126 | |
| 127 d = dcts[row][col]; | |
| 128 if (fabs(d) <= 1.0) { | |
| 129 if (verbose > 3) | |
| 130 fprintf(stderr, "%s: bit #%d - skipped (%d/%d)\n", progname, n, col, row); | |
| 131 continue; | |
| 132 } | |
| 133 | |
| 134 detect = 2 * get_signature1_bit(n) - 1; | |
| 135 | |
| 136 x = (d > 0.0) ? 1.0 : -1.0; | |
| 137 out = 1; | |
| 138 while (fabs(x) < fabs(d)) { | |
| 139 x *= FORWARD_STEP(alpha); | |
| 140 out =- out; | |
| 141 } | |
| 142 | |
| 143 if (verbose > 3) | |
| 144 fprintf(stderr, "%s: detected bit #%d (= %d) at (%d/%d): %f\n", progname, n, out > 0 ? 1 : 0, col, row, d); | |
| 145 | |
| 146 set_signature2_bit(n, out > 0 ? 1 : 0); | |
| 147 sum1 += pow(fabs(d), beta) * out * detect; | |
| 148 sum2 += pow(fabs(d), beta); | |
| 149 | |
| 150 n++; | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
151 } |
| 0 | 152 |
| 153 return sum1 / sum2; | |
| 154 } | |
| 155 | |
| 156 double detect_med_freq(double **dcts, int cols, int rows, int seed, int verbose) { | |
| 157 int i, j, k; | |
| 158 int start= (int) (0.35 * rows * cols + 0.5); | |
| 159 int end = (int) (.65 * rows * cols + 0.5); | |
| 160 | |
| 161 int sum, sum1, sum2; | |
| 162 int x = 0, y = 0, dir = 1; | |
| 163 double *vector; | |
| 164 int startx, starty, startdir; | |
| 165 double corr[2]; | |
| 166 double correlation; | |
| 167 | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
168 // locate start positions |
| 0 | 169 for (i = 0; i < start; i++) { |
| 170 x -= dir; | |
| 171 y += dir; | |
| 172 if (x < 0) { dir = -1; x = 0; } | |
| 173 if (x >= cols) { dir = 1; x = cols - 1; y += 2; } | |
| 174 if (y < 0) { dir = 1; y = 0; } | |
| 175 if (y >= rows) { dir = -1; y = rows - 1; x += 2; } | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
176 } |
| 0 | 177 |
| 178 // save start positions | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
179 startx = x; |
| 0 | 180 starty = y; |
| 181 startdir = dir; | |
| 182 srandom(seed); | |
| 183 | |
| 184 vector = malloc((end - start) * sizeof(double)); | |
| 185 | |
| 186 for (i = 0; i < nbit_signature1; i++) { | |
| 187 | |
| 188 for (j = 0; j <= (end - start); j++) | |
| 189 vector[j] = (double) (random() & RAND_MAX) / (double) RAND_MAX - 0.5; | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
190 |
| 0 | 191 for (j = 0; j <= 1; j++) { |
| 192 x = startx; | |
| 193 y = starty; | |
| 194 dir = startdir; | |
| 195 corr[j] = 0; | |
| 196 | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
197 for (k = 0; start + k < end; k++) { |
| 0 | 198 x -= dir; |
| 199 y += dir; | |
| 200 if (x < 0) { dir = -1; x = 0; } | |
| 201 if (x >= cols) { dir = 1; x = cols - 1; y += 2; } | |
| 202 if (y < 0) { dir = 1; y = 0; } | |
| 203 if (y >= rows) { dir = -1; y = rows - 1; x += 2; } | |
| 204 corr[j] += dcts[y][x] * vector[k + j]; | |
| 205 } | |
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20
bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
|
206 } |
| 0 | 207 |
| 208 set_signature2_bit(i, (corr[0] >= corr[1]) ? 0 : 1); | |
| 209 } | |
| 210 | |
| 211 sum = 0; sum1 = 0; sum2 = 0; | |
| 212 for (i = 0; i < nbit_signature1; i++) { | |
| 213 sum += get_signature1_bit(i) * get_signature2_bit(i); | |
| 214 sum1 += get_signature1_bit(i) * get_signature1_bit(i); | |
| 215 sum2 += get_signature2_bit(i) * get_signature2_bit(i); | |
| 216 } | |
| 217 correlation = (double) sum / (sqrt(sum1) * sqrt(sum2)); | |
| 218 | |
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bd669312f068
suppress warnings, fix link errors
Peter Meerwald-Stadler <pmeerw@pmeerw.net>
parents:
0
diff
changeset
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219 return correlation; |
| 0 | 220 } |