An analysis of the function of a spatial domain filter employed in recent optical syntheses of molecular images from electron holograms is presented. The device is effective in ridding the primary image region of the naturally arising background intensity which, unless filtered, can severely obscure the image. The filter also introduces artifacts, however, which may confuse the interpretation of images, and excessive filtering reduces resolving power. It is shown how to calculate the effect of the filter variables in order to secure a reasonable compromise between resolution, backgroubackground noise, and spurious rings.
© 1979 Optical Society of AmericaPDF Article