AMP (Autocorrelation Mapping Program) is an Intelligent Peak Search Program for Digital Electron Diffraction Images of 3D Nano-crystals. The main tasks of this program include: removal of the background noise, intensifying the signal and locating the real center and the signal positions (coordinates).

In the program, an autocorrelation algorithm is utilized creatively to intensify the signal and to center the image in the particular regular lattice. An adaptive background removal algorithm is designed to remove the central beam and to reduce the background noise.

The program is written in MATLAB for Windows OS. It has been compiled into a standalone executable program for freely download and academic use. If MATLAB software (prefer Version 7.0) is not installed, the MATLAB Component Runtime (MCR) Libraries (300M space on hard disk) need to be installed for running the program properly.

This program will generate 4 output files for each EM image: <image-name>.atc.plt (peak coordinates of autocorrelation image), <image-name>.atc.jpg (autocorrelation image), <image-name>.ctr.pks (peak coordinates of original image), and <image-name>.ctr.png (original image, accurately centered and background removed).

Snapshot 1: Main GUI of the intelligent peak search program – AMP. The image displayed on the left is a digital electron diffraction image of an aspirin nano-crystal with a strong central beam and the shadow of the beam-stop. On the right is given the panel with options for input and output of parameters.

Snapshot 2: Intermediate figures output of AMP. (A) GUI of AMP. (B) Background removed and centered image. (C) Autocorrelation image. (D) Selected peak positions of autocorrelation image. (E) Selected peak positions of centered original images (F) centered original images.