計算機を用いた弱位相物体の電子顕微鏡像の画像修正

抄録

An attempt has been made to correct electron micrographs by using a digital method. A new algorithm to estimate the parameters of CTF has been developed which is based on the calculation of the diffractogram of the electron micrographs and the technique of smooth-ing and differentiation of data based on the least squares method. Suitability of the algorithm is shown through the computer simulation of image restoration by Wiener filtering in which the estimated CTF is inserted. This algorithm has been applied to the actual electron mic-rographs of carbon foils, and image restoration has been carried out successfully. The exp-erimental results for these images are shown. The feature of the digital method of image restoration adopted here is that it can compensate the combined effects of spherical aberration, defocusing, astigmatism, and chromatic aberration, simultaneously, which is almost impossible to realize when the optical method is used alone.