THE FOURIER-TRANSFORM USED AS A TOOL TO EVALUATE SYSTEMS FOR DIGITIZING ELECTRON IMAGES

Image processing methods are commonly used for the structure determina tion of biological molecules using electron microscopy. However, the f irst and crucial step is to convert the electron image intensities int o numerical values to be further processed with the computer. We propo se a simple method based on the Fourier transform to evaluate characte ristics of different digital acquisition systems frequently found in l aboratories, from the video camera linked to the electron microscope t o desktop publishing scanners. Such systems have been chosen in order to represent a wide range of devices and prices.