Mercurial > hg > wm

comparison Meerwald-dir/cmp_xia_sig.c @ 24:9f20bce6184e v0.7

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
move directories, support netpbm 11
author Peter Meerwald-Stadler <pmeerw@pmeerw.net>
date Fri, 20 Dec 2024 13:08:59 +0100
parents Meerwald/cmp_xia_sig.c@f83ef905a63d
children
comparison
equal deleted inserted replaced
23:71dd4b96221b 24:9f20bce6184e
1 #include "wm.h"
2
3 char *progname;
4
5 void usage(void) {
6 fprintf(stderr, "usage: %s [-h] [-C] [-o file] [-v n] -s file file\n\n", progname);
7 fprintf(stderr, "\t-C\t\toutput correlation only\n");
8 fprintf(stderr, "\t-h\t\tprint usage\n");
9 fprintf(stderr, "\t-o file\t\toutput file\n");
10 fprintf(stderr, "\t-v n\t\tverbosity level\n");
11 fprintf(stderr, "\t-s file\t\toriginal signature file\n");
12 exit(0);
13 }
14
15 int main(int argc, char *argv[]) {
16
17 FILE *in = stdin;
18 FILE *out = stdout;
19 FILE *sig = NULL;
20
21 char signature_name[MAXPATHLEN];
22 char output_name[MAXPATHLEN] = "(stdout)";
23 char input_name[MAXPATHLEN] = "(stdin)";
24
25 int c, i, j, n;
26 int in_level;
27 double *cumul_watermark, *orig_watermark;
28 int *cumul_watermark_count;
29 int sig_n, in_n;
30 double sig_a;
31 int sig_l;
32 int sig_e, sig_f;
33 double s1, s2, s3;
34 double correlation, maxcorrelation;
35 char line[32];
36
37 int verbose = 0;
38 int correlation_only = 0;
39
40 progname = argv[0];
41
42 while ((c = getopt(argc, argv, "h?Co:s:v:")) != EOF) {
43 switch (c) {
44 case 'h':
45 case '?':
46 usage();
47 break;
48 case 'C':
49 correlation_only = 1;
50 break;
51 case 'o':
52 if ((out = fopen(optarg, "w")) == NULL) {
53 fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
54 exit(1);
55 }
56 strcpy(output_name, optarg);
57 break;
58 case 's':
59 if ((sig = fopen(optarg, "r")) == NULL) {
60 fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
61 exit(1);
62 }
63 strcpy(signature_name, optarg);
64 break;
65 case 'v':
66 verbose = atoi(optarg);
67 if (verbose < 0) {
68 fprintf(stderr, "%s: verbosity level %d out of range\n", progname, verbose);
69 exit(1);
70 }
71 break;
72 }
73 }
74
75 argc -= optind;
76 argv += optind;
77
78 if (argc > 1) {
79 usage();
80 exit(1);
81 }
82
83 if (argc == 1 && *argv[0] != '-') {
84 if ((in = fopen(argv[0], "r")) == NULL) {
85 fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
86 exit(1);
87 }
88 else
89 strcpy(input_name, argv[0]);
90 }
91
92 if (!sig) {
93 fprintf(stderr, "%s: original signature file not specified, use -s file option\n", progname);
94 exit(1);
95 }
96
97 fgets(line, sizeof(line), sig);
98 if (strspn(line, "XASG") < 4) {
99 fprintf(stderr, "%s: original signature file %s invalid\n", progname, signature_name);
100 exit(1);
101 }
102
103 fgets(line, sizeof(line), in);
104 if (strspn(line, "XAWM") < 4) {
105 fprintf(stderr, "%s: watermark file %s invalid\n", progname, input_name);
106 exit(1);
107 }
108
109 fscanf(sig, "%d\n", &sig_n);
110 fscanf(in, "%d\n", &in_n);
111 if (sig_n != in_n) {
112 fprintf(stderr, "%s: watermark length mismatch (original %d, input %d)\n", progname, sig_n, in_n);
113 exit(1);
114 }
115 if (sig_n <= 0 || sig_n > 32000) {
116 fprintf(stderr, "%s: invalid original watermark length %d\n", progname, sig_n);
117 exit(1);
118 }
119 if (in_n != sig_n) {
120 fprintf(stderr, "%s: invalid watermark length %d, does not match signature length\n", progname, in_n);
121 exit(1);
122 }
123
124 fscanf(sig, "%lf\n", &sig_a);
125 fscanf(sig, "%d\n", &sig_l);
126 fscanf(sig, "%d\n", &sig_e);
127 fscanf(sig, "%d\n", &sig_f);
128 fscanf(sig, "%*[^\n\r]\n");
129
130 orig_watermark = malloc(sig_n * sizeof(double));
131 for (i = 0; i < sig_n; i++)
132 fscanf(sig, "%lf\n", &orig_watermark[i]);
133 fclose(sig);
134
135 fscanf(in, "%d\n", &in_level);
136
137 cumul_watermark = malloc(in_n * sizeof(double));
138 cumul_watermark_count = malloc(in_n * sizeof(int));
139
140 for (i = 0; i < in_n; i++) {
141 cumul_watermark_count[i] = 0;
142 cumul_watermark[i] = 0.0;
143 }
144
145 /*
146 * normalized correlation
147 * Craver, S., "Can Invisible Watermarks Resolve Rightful Ownership?", IBM Research Report, 1996, p. 5
148 */
149
150 maxcorrelation = -10000.0;
151 for (i = 0; i < in_level; i++) {
152 fscanf(in, "%d\n", &n);
153
154 s1 = s2 = s3 = 0.0;
155 for (j = 0; j < n; j++) {
156 double in_x, sig_x;
157
158 sig_x = orig_watermark[j % sig_n];
159 fscanf(in, "%lf\n", &in_x);
160
161 s1 += sig_x * in_x;
162 s2 += in_x * in_x;
163 s3 += sig_x * sig_x;
164
165 if (verbose > 2)
166 fprintf(stderr, "%s: level %d; orig %f input %f\n", progname, i, sig_x, in_x);
167
168 cumul_watermark[j % in_n] += in_x;
169 cumul_watermark_count[j % in_n]++;
170 }
171
172 correlation = s1 / sqrt(s2 * s3);
173 if (correlation > maxcorrelation)
174 maxcorrelation = correlation;
175
176 if (!correlation_only)
177 fprintf(out, "%s: correlation subband %d: %f\n", progname, i, correlation);
178 }
179
180 s1 = s2 = s3 = 0.0;
181 for (i = 0; i < in_n; i++) {
182 double in_x, sig_x;
183
184 if (cumul_watermark_count[i] <= 0) continue;
185 in_x = cumul_watermark[i] / (double) cumul_watermark_count[i];
186 sig_x = orig_watermark[i];
187
188 s1 += sig_x * in_x;
189 s2 += in_x * in_x;
190 s3 += sig_x * sig_x;
191 }
192
193 correlation = s1 / sqrt(s2 * s3);
194 if (!correlation_only)
195 fprintf(out, "%s: cumultative correlation: %f\n", progname, correlation);
196
197 if (correlation > maxcorrelation)
198 maxcorrelation = correlation;
199
200 if (!correlation_only)
201 fprintf(out, "%s: max. correlation: %f\n", progname, maxcorrelation);
202 else
203 fprintf(out, "%f\n", maxcorrelation);
204
205 fclose(out);
206 fclose(in);
207
208 free(orig_watermark);
209 free(cumul_watermark);
210 free(cumul_watermark_count);
211
212 exit(0);
213 }

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.