--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Meerwald-dir/kim_common.c	Fri Dec 20 13:08:59 2024 +0100
@@ -0,0 +1,60 @@
+#include "wm.h"
+#include "kim_common.h"
+
+
+// find the largest absolute coefficient of a subband
+double find_subband_largest_coeff(Image_tree s, int subband, int verbose) {
+  int i, j;
+  double max;
+
+  max = 0.0;
+  for (i = 5; i < s->image->height-5; i++)
+    for (j = 5; j < s->image->width-5; j++) {
+      double coeff;
+
+      coeff = fabs(get_pixel(s->image, i, j));
+      if (coeff > max) 
+        max = coeff;
+    }
+
+  if (verbose > 8)
+    fprintf(stderr, "  subband %f\n", max);
+
+  return max;
+}
+
+// find largest absolute coefficient of the detail subbands (LH, HL, HH) of 
+// a decomposition level
+double find_level_largest_coeff(Image_tree p, int verbose) {
+  double h, v, d;
+
+  h = find_subband_largest_coeff(p->horizontal, HORIZONTAL, verbose);
+  v = find_subband_largest_coeff(p->vertical, VERTICAL, verbose);
+  d = find_subband_largest_coeff(p->diagonal, DIAGONAL, verbose);
+
+  return MAX(h, MAX(v, d));
+}
+
+// calculate the significance threshold given the maximum absolute
+// coefficient at a decomposition level
+double calc_level_threshold(double max_coeff, int verbose) {
+  double threshold;
+
+  threshold = pow(2.0, floor(log(max_coeff) / log(2.0)) - 1.0);
+
+  if (verbose > 7)
+    fprintf(stderr, "  max %f, threshold %f\n", max_coeff, threshold);
+
+  return threshold;
+}
+
+// calculate an appropriate embedding strength for a given decomposition level
+// and a base alpha strength
+double calc_level_alpha_detail(double alpha, int maxlevels, int level, int verbose) {
+  double level_alpha;
+
+  level_alpha = alpha / pow(2.0, level - 1);
+
+  return level_alpha;
+}
+