Simulating Partial Occlusion in Post-Processing Depth-of-Field Methods

GPU Pro 4 ◽  
2013 ◽  
pp. 203-216
2013 ◽  
Vol 278-280 ◽  
pp. 50-53
Author(s):  
Qing Hua Lv ◽  
Xiao Zhu ◽  
Zhong Bao Xu ◽  
Zhong Sheng Zhai ◽  
Shuang Zou

Abstract. A diffraction limited circularly symmetric optical imaging system with “0,π” phase pupil mask was studied, which extended depth of field. The optimal radiuses of the mask in the different amount of defocus are calculated, which in a certain contrast value 0.05 and 0.1, can provide the largest spatial frequency band. On the other hand, the effect of mask manufacturing error is analyzed, and the performance of the simulation imaging system has been verified experimentally that the image system still can obtain the high quality output images even without any post-processing.


2014 ◽  
Vol 40 (1) ◽  
pp. 29-40 ◽  
Author(s):  
L.M. Ledesma-Carrillo ◽  
M. Lopez-Ramirez ◽  
C.A. Rivera-Romero ◽  
A. Garcia-Perez ◽  
G. Botella ◽  
...  

Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.


Author(s):  
Emil Bernstein

An interesting method for examining structures in g. pig skin has been developed. By modifying an existing technique for splitting skin into its two main components—epidermis and dermis—we can in effect create new surfaces which can be examined with the scanning electron microscope (SEM). Although this method is not offered as a complete substitute for sectioning, it provides the investigator with a means for examining certain structures such as hair follicles and glands intact. The great depth of field of the SEM complements the technique so that a very “realistic” picture of the organ is obtained.


Author(s):  
A.M. Jones ◽  
A. Max Fiskin

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.


Author(s):  
K. Culbreth

The introduction of scanning electron microscopy and energy dispersive x-ray analysis to forensic science has provided additional methods by which investigative evidence can be analyzed. The importance of evidence from the scene of a crime or from the personal belongings of a victim and suspect has resulted in the development and evaluation of SEM/x-ray analysis applications to various types of forensic evidence. The intent of this paper is to describe some of these applications and to relate their importance to the investigation of criminal cases.The depth of field and high resolution of the SEM are an asset to the evaluation of evidence with respect to surface phenomena and physical matches (1). Fig. 1 shows a Phillips screw which has been reconstructed after the head and shank were separated during a hit-and-run accident.


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