Make lower limit to 'width' (ie. stddev) of normal distribution function.

1 files changed, 13 insertions, 1 deletions

diff --git a/src/powerlist.cc b/src/powerlist.cc
index 1888733..96f2c9b 100644
--- a/src/powerlist.cc
+++ b/src/powerlist.cc
@@ -32,6 +32,14 @@
 
 #include <hugin.hpp>
 
+/**
+ * Minimum sample set size.
+ * Smaller means wider 'velocity groups'.
+ * Limited by sample set size, ie. only kicks in if sample set size is smaller
+ * than this number.
+ */
+#define MIN_SAMPLE_SET_SIZE 10
+
 // Enable to calculate power on old samples without power attribute
 //#define AUTO_CALCULATE_POWER
 
@@ -213,8 +221,12 @@ Sample *PowerList::get(level_t level)
 
   float power_span = power_max - power_min;
 
+  // Width is limited to at least 10. Fioxes problem with instrument with a
+  //  sample set smaller than MIN_SAMPLE_SET_SIZE.
+  float width = fmax(samples.size(), MIN_SAMPLE_SET_SIZE);
+
   // Spread out at most 1.5 samples away from center 
-  float stddev = power_span / samples.size() * 1.5;
+  float stddev = power_span / width * 1.5;
 
   // Cut off mean value with stddev/2 in both ends in order to make room for
   //  downwards expansion on velocity 0 and upwards expansion on velocity 1.