Unbend :
A graphical interface for unbending filaments. (Download for Mac OS 10.4 and 10.5
Intel version or PowerPC version)

When you use Ruby-Helix or Unbend, please refer to the following publications:

Metlagel, Z., Y. S. Kikkawa, and M. Kikkawa
Ruby-Helix : An implementation of helical image processing based on object-oriented scripting language
J. Struc. Biol. 157:95-105, 2007