Interior imaging using spatial frequency sampling

1981 ◽  
Vol 2 (3-4) ◽  
pp. 203-207
Author(s):  
E. El-Shirbini ◽  
D. A. Sinclair ◽  
I. R. Smith
Keyword(s):  
Spatial Frequency ◽  
Frequency Sampling

Spatial frequency sampling look-up table method for computer-generated hologram

2016 ◽  
Vol 55 (4) ◽  
pp. 043101
Author(s):  
Kai Zhao ◽  
Yingqing Huang ◽  
Xiaoyu Jiang ◽  
Xingpeng Yan
Keyword(s):  
Spatial Frequency ◽  
Computer Generated Hologram ◽  
Table Method ◽  
Look Up Table ◽  
Frequency Sampling

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

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