AIR (Automated Image Registration) is a program suite for volume-based image registration constructed by Roger P. Woods from UCLA School of Medicine.It reads and writes Analyze volume files and can work with 4x4 transformation matrices stored in its own file format with the filename extension .air. It is especially designed for neuroimaging applications and has primarily been used in research-oriented functional neuroimaging with brain scans from positron emission tomography and magnetic resonance scanners.