Calculation of the influence of lateral chromatic aberration on image quality across the visual field

1987 ◽  
Vol 4 (8) ◽  
pp. 1673 ◽  
Author(s):  
L. N. Thibos
Keyword(s):  
Visual Field ◽  
Image Quality ◽  
Chromatic Aberration ◽  
Lateral Chromatic Aberration

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

scholarly journals Removing lateral chromatic aberration in bright field optical microscopy

2015 ◽  
Vol 23 (11) ◽  
pp. 14380 ◽  
Author(s):  
Miguel Guzmán-Altamirano ◽  
Braulio Gutiérrez-Medina
Keyword(s):  
Optical Microscopy ◽  
Chromatic Aberration ◽  
Bright Field ◽  
Lateral Chromatic Aberration

A neural and computational model for the chromatic control of accommodation

1990 ◽  
Vol 5 (6) ◽  
pp. 547-555 ◽  
Author(s):  
D. I. Flitcroft
Keyword(s):  
Image Quality ◽  
Computational Model ◽  
Cortical Neurons ◽  
Chromatic Aberration ◽  
Refractive State ◽  
Spatial Frequencies ◽  
Proposed Model ◽  
Band Pass ◽  
Chromatic Cues ◽  
Chromatic Processing

AbstractAccommodation is more accurate with polychromatic stimuli than with narrowband or monochromatic stimuli. The aim of this paper is to develop a computational model for how the visual system uses the extra information in polychromatic stimuli to increase the accuracy of accommodation responses. The proposed model is developed within the context of both trichromacy and also the organization of spatial and chromatic processing within the visual cortex.The refractive error present in the retinal image can be estimated by comparing image quality with and without small additional changes in refractive state. In polychromatic light, the chromatic aberration of the eye results in differences in ocular refractive power for light of different wavelengths. As a result, the refractive state of the eye can be estimated by comparing image quality in the three types of cone photoreceptor. The ability of cortical neurons to perform such comparisons on image quality with a crude form of spatial-frequency analysis is examined theoretically. It is found that spatially band-pass chromatically opponent neurons (that may correspond to double opponent neurons) can perform such calculations and that chromatic cues to accommodation are extracted most effectively by neurons responding to spatial frequencies of between 2 and 8 cycles/deg.

scholarly journals TTL Alignment for Excimer Laser Aligner. Real-Time SMART with Correcting Lateral Chromatic Aberration.

1993 ◽  
Vol 59 (1) ◽  
pp. 101-106
Author(s):  
Tatsuhiko HIGASHIKI ◽  
Toru TOJO ◽  
Mitsuo TABATA ◽  
Takeshi NISHIZAKA ◽  
Hisakazu YOSHINO ◽  
...  
Keyword(s):  
Real Time ◽  
Excimer Laser ◽  
Chromatic Aberration ◽  
Lateral Chromatic Aberration
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