A fast color cast detection and correction method for large-field video-image in nature scene

2018 ◽  
Author(s):  
Ke Hong ◽  
Yu Shi ◽  
Xia Hua
Keyword(s):  
Correction Method ◽  
Video Image ◽  
Large Field ◽  
Nature Scene ◽  
Color Cast

An Error Correction Method Research Based on Large Field Reflecting Telescope

2015 ◽  
Vol 35 (6) ◽  
pp. 0611005
Author(s):  
周龙峰 Zhou Longfeng ◽  
张昂 Zhang Ang ◽  
张俊波 Zhang Junbo ◽  
鲜浩 Xian Hao
Keyword(s):  
Error Correction ◽  
Correction Method ◽  
Large Field ◽  
Error Correction Method

Eccentricity Measurement of Auto-Hub's Pitch Circle

2013 ◽  
Vol 431 ◽  
pp. 121-125
Author(s):  
Shu Xia Guo ◽  
Bin Feng ◽  
Liang Zhang ◽  
Wei Zhang ◽  
Lei Wang
Keyword(s):  
Imaging System ◽  
Vision System ◽  
Correction Method ◽  
Large Field ◽  
Height Difference ◽  
Maximum Variation ◽  
Fitting Algorithm ◽  
Bolt Holes ◽  
Perspective Distortions ◽  
Telecentric Lens

In order to measure the eccentricity of auto-hubs center hole and bolt holes, a machine vision system is proposed in this article. Instead of normally used telecentric lens, a perspective lens is used in the vision system because of the large field of view. The eccentricity is calculated by sub-pixel edge extracting and circle-fitting algorithm. A correction method is put forward to compensate the systematic error resulting from the different perspective distortions of the center hole and the bolt holes because of the height difference between the center hole and the bolt holes, as well as the offset between the hubs center shaft and the optical axis of the imaging system. The maximum variation and the standard variation are calculated to analyze the measurement uncertainty. Experiments had shown that the maximum variation and the standard deviation of the corrected measured eccentricity were reduced to 1/6 and 1/8 of those without correction.

scholarly journals Inherent Geometry Correction for Diffusion EPI Using the Reference Echoes as Navigators

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Johan S. van den Brink ◽  
Jos J. Koonen
Keyword(s):  
Parallel Imaging ◽  
Reference Data ◽  
Correction Method ◽  
Field Of View ◽  
Large Field ◽  
Additional Time ◽  
Body Imaging ◽  
Starting Point ◽  
Indispensable Tool ◽  
Geometry Correction

Diffusion-weighted EPI has become an indispensable tool in body MRI. Geometric distortions due to field inhomogeneities are more prominent at large field–of–view and require correction for comparison with T2W TSE. Several known correction methods require acquisition of additional lengthy scans, which are difficult to apply in body imaging. We implement and evaluate a geometry correction method based on the already available non phase-encoded EPI reference data used for Nyquist ghost removal. The method is shown to provide accurate and robust global geometry correction in the absence of strong, local phase offsets. It does not require additional time for calibrations and is directly compatible with parallel imaging methods. The resulting images can serve as improved starting point for additional geometry correction methods relying on feature extraction and registration.

Ortho-k lenses fitting in patients with “non-typical” corneas

The Eye ◽  
2020 ◽  
Vol 22 (129) ◽  
pp. 22-29
Author(s):  
Svetlana Kravchuk ◽  
Olga Zhabina
Keyword(s):  
Correction Method ◽  
Diameter Ratio ◽  
Corneal Curvature ◽  
Individual Approach ◽  
Fitting In ◽  
Corneal Diameter ◽  
Clinical Cases

We described two clinical cases of ortho-k lenses fitting in patients with “non-typical” corneal curvature/diameter ratio. The main goal was to acknowledge effective and safe use of this myopia correction method in patients with corneal diameter greater than 11 mm. Individual approach to each patient is the key to a successful and safe ortho-k lenses fitting.

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