IMAGE-PROCESSING AND FINE-STRUCTURE OF HYDROXYAPATITE PARTICLES

Interpretation of high resolution electron microscope (HREM) images of small hydroxyapatite (OHAp) crystals with image processing using Four ier filtration techniques has been performed. The effects of digitizin g filter parameters in relation to the extent of possible artefacts -l ike crystal bleeding -which limit the correct image interpretation hav e been tested. Image processing for OHAp crystallites was applied in t wo different cases: (i) crystal inhomogeneities (void boundaries) wher e image provides a good test for the extension of the bleeding in reco nstructed images; (ii) beam-induced domains with different crystal str ucture (or different orientation) than the OHAp matrix where processin g provides a test on the precise location and contrast enhancement of those secondary structures.