The Reconstruction of Off-Axis Electron Holograms

The full digital reconstruction of off-axis TEM holograms involves algorithms (FFTs) which use significant CPU time even on fast computers. For example, on a Macintosh computer (G3 at 307 MHz), the reconstruction time for a 1024 by 1024 pixel image (including the display of the phase and amplitude image) is slightly below 4 seconds. On a DEC 3000 AXP 600 workstation the reconstruction time is about 8 seconds. For the live display of phase images, reconstruction procedures which speed the process by either making assumptions about the object or by using a mixture of optical and digital methods are an important tool for electron holography.