The file 'p1.sml.dat' is a 3d array of 8 bit data values sampled on a
128x128x54 regular grid.  the voxel size is uniform in all three
dimensions.

Each sample (one byte) is a value between 0 and 255 and represents
"time of flight" in a Magnetic Resonance Angiography data set of a
human brain.  We are mainly interested in the vessels, where the time
of flight should be relatively "high".

The file 'p1read.c' contains a sample "C" program that illustrates how
to read the data.