Defocus imaging

Toyoshima C and Unwin P N T 1988 Contrast transfer for frozen-hydrated specimens determination from pairs of defocus images Uitramicroscopy 25 279-92... 

Spatial resolution is a function of altitude of the backscattering region Hi, since the size of the defocus image writes D Hj — Hi)/ HfHi). With Hf 25km and Hi =11 km and if the spot is observed with a resolution of 1 arcsec, then when projected to the pupil the resolution is 5 x Hf Hi)/ Hf — Hi) 0.26m. At a 32 m, the defocus image is 2 arcmin wide. 

Van Dam, M.A., Lane, R.G., 2002, Wave-front sensing from defocused images by use of wave-front slopes, Appl. Opt. 26, 5497... 

Roddier, C., Roddier, R, 1993, Wave-front reconstruction from defocused images and the testing of ground-based optical telescopes, JOSA.A 10, 2277 (1993). 

An example of the use of Fresnel defocus imaging, diffuse dark field imaging and HRTEM to examine the same SiC-SiC interface is shown in Fig. 17.1 (Turan, 1995). All three techniques clearly indicate the presence of... 

Figure 7 (a) Wide-field image in focus and (b) corresponding defocused image of perylene diimide dye molecules embedded in a 300-nm-thick poly(/j-butyl methacrylate) matrix. 

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