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comparison Meerwald/cmp_cox_sig.c @ 0:be303a3f5ea8

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import
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Sun, 12 Aug 2007 13:14:34 +0200
parents
children f83ef905a63d
comparison
equal deleted inserted replaced
-1:000000000000 0:be303a3f5ea8
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-s file\t\toriginal signature file\n");
11 fprintf(stderr, "\t-v n\t\tverbosity level\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;
26 int sig_n, in_n;
27 double sig_a, in_a;
28 double sig_mean, sig_variance;
29 double s1, s2, s3;
30 char line[32];
31
32 int verbose = 0;
33 int correlation_only = 0;
34
35 progname = argv[0];
36
37 while ((c = getopt(argc, argv, "h?Co:s:v:")) != EOF) {
38 switch (c) {
39 case 'h':
40 case '?':
41 usage();
42 break;
43 case 'C':
44 correlation_only = 1;
45 break;
46 case 'o':
47 if ((out = fopen(optarg, "w")) == NULL) {
48 fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
49 exit(1);
50 }
51 strcpy(output_name, optarg);
52 break;
53 case 's':
54 if ((sig = fopen(optarg, "r")) == NULL) {
55 fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
56 exit(1);
57 }
58 strcpy(signature_name, optarg);
59 break;
60 case 'v':
61 verbose = atoi(optarg);
62 if (verbose < 0) {
63 fprintf(stderr, "%s: verbosity level %d out of range\n", progname, verbose);
64 exit(1);
65 }
66 break;
67 }
68 }
69
70 argc -= optind;
71 argv += optind;
72
73 if (argc > 1) {
74 usage();
75 exit(1);
76 }
77
78 if (argc == 1 && *argv[0] != '-')
79 if ((in = fopen(argv[0], "r")) == NULL) {
80 fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
81 exit(1);
82 }
83 else
84 strcpy(input_name, argv[0]);
85
86 if (!sig) {
87 fprintf(stderr, "%s: original signature file not specified, use -s file option\n", progname);
88 exit(1);
89 }
90
91 fgets(line, sizeof(line), sig);
92 if (strspn(line, "CXSG") < 4) {
93 fprintf(stderr, "%s: original signature file %s invalid\n", progname, signature_name);
94 exit(1);
95 }
96
97 fgets(line, sizeof(line), in);
98 if (strspn(line, "CXWM") < 4) {
99 fprintf(stderr, "%s: watermark file %s invalid\n", progname, input_name);
100 exit(1);
101 }
102
103 fscanf(sig, "%d\n", &sig_n);
104 fscanf(in, "%d\n", &in_n);
105 if (sig_n != in_n) {
106 fprintf(stderr, "%s: watermark length mismatch (original %d, input %d)\n", progname, sig_n, in_n);
107 exit(1);
108 }
109 if (sig_n <= 0 || sig_n > 32000) {
110 fprintf(stderr, "%s: invalid original watermark length %d\n", progname, sig_n);
111 exit(1);
112 }
113 if (in_n <= 0 || in_n > 32000) {
114 fprintf(stderr, "%s: invalid watermark length %d\n", progname, in_n);
115 exit(1);
116 }
117
118 fscanf(sig, "%lf\n", &sig_a);
119
120 fscanf(sig, "%lf\n", &sig_mean);
121 fscanf(sig, "%lf\n", &sig_variance);
122
123 /*
124 * normalized correlation
125 * Craver, S., "Can Invisible Watermarks Resolve Rightful Ownership?", IBM Research Report, 1996, p. 5
126 */
127
128 s1 = s2 = s3 = 0.0;
129 while (in_n > 0) {
130 double sig_x, in_x;
131
132 fscanf(sig, "%lf\n", &sig_x);
133 fscanf(in, "%lf\n", &in_x);
134
135 if (verbose >= 1) {
136 fprintf(stderr, "orig %f input %f\n", sig_x, in_x);
137 }
138
139 s1 += sig_x * in_x;
140 s2 += in_x * in_x;
141 s3 += sig_x * sig_x;
142
143 in_n--;
144 }
145
146 fprintf(out, "%f\n", s1 / sqrt(s2 * s3));
147
148 fclose(sig);
149 fclose(out);
150 fclose(in);
151
152 exit(0);
153 }

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