For whatever reason, Matlab 2008a doesn’t like the mex files that come with the steerable pyramid toolbox. If you try to recompile the mex files with Matlab’s built-in compiler, you will find that it crashes whenever you call buildSpyr. You can do the following to get it to work:

1. Install Visual C++ express edition.
2. Restart your computer
3. In Matlab, type mex -setup. Ask it to locate installed compilers. It should find the Microsoft C++ compiler in C:\Program Files\Microsoft Visual Studio 9.0. Select it, and it should update the options file.
4. Change your Matlab working directory to the MEX folder of the steerable pyramid toolbox. Delete all of the .mex files you see in there.
5. Type the following commands in the Matlab command window:
   1. mex corrDn.c wrap.c convolve.c edges.c
   2. mex upConv.c wrap.c convolve.c edges.c
   3. mex pointOp.c
   4. mex histo.c
   5. mex range2.c
6. Now add the MEX folder to your Matlab path, and the toolbox should use the new mex files which appear to work fine.