Create Subversion repository

git-svn-id: http://svn.code.sf.net/p/netpbm/code/trunk@1 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 209 insertions, 0 deletions

diff --git a/analyzer/pnmpsnr.c b/analyzer/pnmpsnr.c
new file mode 100644
index 00000000..4a6bfe56
--- /dev/null
+++ b/analyzer/pnmpsnr.c
@@ -0,0 +1,209 @@
+/*
+ *  pnmpsnr.c: Compute error (RMSE, PSNR) between images
+ *
+ *
+ *  Derived from pnmpnsmr by Ulrich Hafner, part of his fiasco package,
+ *  On 2001.03.04.
+
+ *  Copyright (C) 1994-2000 Ullrich Hafner <hafner@bigfoot.de>
+ */
+
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+
+#include "pm_c_util.h"
+#include "pam.h"
+
+#define MAXFILES 16
+
+static int
+udiff(unsigned int const subtrahend, unsigned int const subtractor) {
+    return subtrahend-subtractor;
+}
+
+
+static double
+square(double const arg) {
+    return(arg*arg);
+}
+
+
+static void
+validate_input(const struct pam pam1, const struct pam pam2) {
+
+    if (pam1.width != pam2.width)
+        pm_error("images are not the same width, so can't be compared.  "
+                 "The first is %d columns wide, "
+                 "while the second is %d columns wide.",
+                 pam1.width, pam2.width);
+    if (pam1.height != pam2.height)
+        pm_error("images are not the same height, so can't be compared.  "
+                 "The first is %d rows high, "
+                 "while the second is %d rows high.",
+                 pam1.height, pam2.height);
+
+    if (pam1.maxval != pam2.maxval)
+        pm_error("images do not have the same maxval.  This programs works "
+                 "only on like maxvals.  "
+                 "The first image has maxval %u, "
+                 "while the second has %u.  Use Pnmdepth to change the "
+                 "maxval of one of them.",
+                 (unsigned int) pam1.maxval, (unsigned int) pam2.maxval);
+
+    if (strcmp(pam1.tuple_type, pam2.tuple_type) != 0)
+        pm_error("images are not of the same type.  The tuple types are "
+                 "'%s' and '%s', respectively.",
+                 pam1.tuple_type, pam2.tuple_type);
+
+    if (strcmp(pam1.tuple_type, PAM_PBM_TUPLETYPE) != 0 &&
+        strcmp(pam1.tuple_type, PAM_PGM_TUPLETYPE) != 0 &&
+        strcmp(pam1.tuple_type, PAM_PPM_TUPLETYPE) != 0)
+        pm_error("Images are not of a PNM type.  Tuple type is '%s'",
+                 pam1.tuple_type);
+}
+
+
+
+static void
+psnr_color(tuple const tuple1, tuple const tuple2,
+           double * const ySqDiffP, 
+           double * const cbSqDiffP, double * const crSqDiffP) {
+
+    double y1, y2, cb1, cb2, cr1, cr2;
+    
+    pnm_YCbCrtuple(tuple1, &y1, &cb1, &cr1);
+    pnm_YCbCrtuple(tuple2, &y2, &cb2, &cr2);
+    
+    *ySqDiffP =  square(y1  - y2);
+    *cbSqDiffP = square(cb1 - cb2);
+    *crSqDiffP = square(cr1 - cr2);
+}
+
+
+
+static void
+reportPsnr(struct pam const pam1, struct pam const pam2, 
+           double const ySumSqDiff, 
+           double const crSumSqDiff, double const cbSumSqDiff,
+           const char filespec1[], const char filespec2[]) {
+
+    bool const color = (strcmp(pam1.tuple_type, PAM_PPM_TUPLETYPE) == 0);
+
+    /* The PSNR is the mean of the sum of squares of the differences,
+       normalized to the range 0..1
+    */
+    double const yPsnr = ySumSqDiff 
+        / (pam1.width * pam1.height) 
+        / square(pam1.maxval);
+
+    if (color) {
+        double const cbPsnr = cbSumSqDiff 
+            / (pam1.width * pam1.height) 
+            / square(pam1.maxval);
+        double const crPsnr = crSumSqDiff 
+            / (pam1.width * pam1.height) 
+            / (pam1.maxval * pam2.maxval);
+
+        pm_message("PSNR between %s and %s:", filespec1, filespec2);
+        if (yPsnr > 1e-9)
+            pm_message("Y  color component: %.2f dB", 10 * log10(1/yPsnr));
+        else
+            pm_message("Y color component does not differ.");
+        if (cbPsnr > 1e-9)
+            pm_message("Cb color component: %.2f dB", 10 * log10(1/cbPsnr));
+        else
+        pm_message("Cb color component does not differ.");
+        if (crPsnr > 1e-9)
+            pm_message("Cr color component: %.2f dB", 10 * log10(1/crPsnr));
+        else
+            pm_message("Cr color component does not differ.");
+    } else {
+        if (yPsnr > 1e-9)
+            pm_message("PSNR between %s and %s: %.2f dB",
+                       filespec1, filespec2, 10 * log10(1/yPsnr));
+        else
+            pm_message("Images %s and %s don't differ.",
+                       filespec1, filespec2);
+    }
+}
+
+
+
+int
+main (int argc, char **argv) {
+    char *filespec1, *filespec2;  /* specs of two files to compare */
+    FILE *file1, *file2;
+    struct pam pam1, pam2;
+    bool color;
+        /* It's a color image */
+    double ySumSqDiff, crSumSqDiff, cbSumSqDiff;
+    tuple *tuplerow1, *tuplerow2;  /* malloc'ed */
+    int row;
+    
+    pnm_init(&argc, argv);
+
+    if (argc < 2) 
+        pm_error("Takes two arguments:  specifications of the two files.");
+    else {
+        filespec1 = argv[1];
+        filespec2 = argv[2];
+    }
+    
+    file1 = pm_openr(filespec1);
+    file2 = pm_openr(filespec2);
+
+    pnm_readpaminit(file1, &pam1, PAM_STRUCT_SIZE(tuple_type));
+    pnm_readpaminit(file2, &pam2, PAM_STRUCT_SIZE(tuple_type));
+
+    validate_input(pam1, pam2);
+
+    if (strcmp(pam1.tuple_type, PAM_PPM_TUPLETYPE) == 0) 
+        color = TRUE;
+    else
+        color = FALSE;
+
+    tuplerow1 = pnm_allocpamrow(&pam1);
+    tuplerow2 = pnm_allocpamrow(&pam2);
+    
+    ySumSqDiff = 0.0;
+    cbSumSqDiff = 0.0;
+    crSumSqDiff = 0.0;
+
+    for (row = 0; row < pam1.height; ++row) {
+        int col;
+        
+        pnm_readpamrow(&pam1, tuplerow1);
+        pnm_readpamrow(&pam2, tuplerow2);
+
+        for (col = 0; col < pam1.width; ++col) {
+            if (color) {
+                double ySqDiff, cbSqDiff, crSqDiff;
+                psnr_color(tuplerow1[col], tuplerow2[col], 
+                           &ySqDiff, &cbSqDiff, &crSqDiff);
+                ySumSqDiff += ySqDiff;
+                cbSumSqDiff += cbSqDiff;
+                crSumSqDiff += crSqDiff;
+                
+            } else {
+                unsigned int yDiffSq;
+                yDiffSq = square(udiff(tuplerow1[col][0], tuplerow2[col][0]));
+                ySumSqDiff += yDiffSq;
+            }
+        }
+    }
+
+    reportPsnr(pam1, pam2, ySumSqDiff, crSumSqDiff, cbSumSqDiff,
+               filespec1, filespec2);
+
+    pnm_freepamrow(tuplerow1);
+    pnm_freepamrow(tuplerow2);
+
+    return 0;
+}
+
+
+
+
+
+