suppress tiny bins that are most likely due to floating-point inaccuracy

Device/Detector/IDetector.cpp

@@ -42,12 +42,21 @@ inline size_t ycoord(size_t index, size_t sizeY)
 IDetector::RoiOfAxis::RoiOfAxis(const Scale& axis, double _lower, double _upper)
     : lower(_lower)
     , upper(_upper)
-    , lowerIndex(axis.closestIndex(lower))
-    , upperIndex(axis.closestIndex(upper))
-    , roiSize(upperIndex - lowerIndex + 1)
-    , detectorSize(axis.size())
 {
     ASSERT(lower < upper);
+    detectorSize = axis.size();
+    lowerIndex = axis.closestIndex(lower);
+    upperIndex = axis.closestIndex(upper);
+    // suppress tiny bins that are most likely due to floating-point inaccuracy
+    if (axis.bin(lowerIndex).binSize() < 1e-12 * axis.span() / axis.size()) {
+        ASSERT(lowerIndex < axis.size() - 1);
+        ++lowerIndex;
+    }
+    if (axis.bin(upperIndex).binSize() < 1e-12 * axis.span() / axis.size()) {
+        ASSERT(upperIndex > 0);
+        --upperIndex;
+    }
+    roiSize = upperIndex - lowerIndex + 1;
 }
 
 std::pair<double, double> IDetector::RoiOfAxis::bounds() const