Read SPIDER files

Read and write files in SPIDER format

Description

SPIDER is a free image processing system for electron microscopy. It is used for three-dimensional reconstruction of single particle macromolecules, multivariate statistical classification, and electron tomography. See the extensive documentation and many available techniques at www.wadsworth.org/spider_doc/spider/docs/master.html

SPIDER has its own binary format for images and volumes. The SPIDER M-file collection lets users read SPIDER images, volumes, image stacks, and textual document files directly into Matlab data types for processing and visualization.

• MATLAB release: MATLAB 7.6 (R2008a)

[Charles Sindelar]

Thank you Bill for a very useful set of routines.
I have discovered a problem with writeSPIDERfile.m when it is used with Octave, an open-source matlab equivalent, so I thought I would share the fix. The problem is that the header length is computed wrong by the line:

labrec = uint32(1024 / lenbyt);

In Octave, at least, "uint32" seems to perform a rounding operation, whereas the correct operation is a "floor". So, the following fix appears to work just fine:

labrec = uint32(floor(1024 / lenbyt));