--- a/liboctave/fNDArray.cc
+++ b/liboctave/fNDArray.cc
@@ -41,6 +41,14 @@
 #include "oct-locbuf.h"
 #include "mx-op-defs.h"
 
+FloatNDArray::FloatNDArray (const charNDArray& a)
+  : MArrayN<float> (a.dims ())
+{
+  octave_idx_type n = a.numel ();
+  for (octave_idx_type i = 0; i < n; i++)
+    xelem (i) = static_cast<unsigned char> (a(i));
+}
+
 #if defined (HAVE_FFTW3)
 #include "oct-fftw.h"