The advance of digital recording and energy filtering now makes it possible to extract quantitative crystal structure information in an accuracy close to or better than the x-ray method. The extraction of structure information employs the refinement technique by comparing theory and experiment using chisquare criteria of

For the unit cell or crystal orientation determination, the experiment yx is the line equation of Kikuchi or HOLZ lines, and/or positions of convergent beam disks or diffraction spots. Lines, or disks, can be measured directly from the digitally recorded two-dimensional patterns using techniques of image processing and transformation such as Hough. A practical method for measuring unit cell parameters was described by [1]. For the determination of atomic positions, the experiment yx is the diffracted intensities of medium and high order reflections. For the measurement of charge density, the yx is the energy-filtered diffracted intensities of low order reflections or high order reflections coupled with a low order reflections.