A method to study the crystal defects at atomic level by high-resolution electron microscopy (HREM) is introduced. The image taken with a field-emission high-resolution electron microscope and not directly reflecting the examined crystal structure can be transformed into the structure image by means of image deconvolution in combination with dynamical scattering effect correction. The principle of image deconvolution and the procedure of technique are briefly introduced. The results of applications on the epilayer of Si_0.76Ge_0.24/Si are given. It is shown that atoms in the dislocation core structures have been distinguished individually in the deconvoluted images and the point resolution of images can be improved up to the information limit of the field-emission high-resolution electron microscope.