Optical distortion in the field of a lithotripter shock wave

1995 ◽  
Vol 34 (28) ◽  
pp. 6465 ◽  
Author(s):  
M. T. Carnell ◽  
D. C. Emmony
Keyword(s):  
Shock Wave ◽  
Optical Distortion

scholarly journals Registration Error Analysis for Augmented Reality

1997 ◽  
Vol 6 (4) ◽  
pp. 413-432 ◽  
Author(s):  
Richard L. Holloway
Keyword(s):  
Augmented Reality ◽  
Error Analysis ◽  
Optical Distortion ◽  
Calibration Error ◽  
Head Tracking ◽  
System Delay ◽  
System Calibration ◽  
The Real ◽  
Registration Error ◽  
Real Environment

Augmented reality (AR) systems typically use see-through head-mounted displays (STHMDs) to superimpose images of computer-generated objects onto the user's view of the real environment in order to augment it with additional information. The main failing of current AR systems is that the virtual objects displayed in the STHMD appear in the wrong position relative to the real environment. This registration error has many causes: system delay, tracker error, calibration error, optical distortion, and misalignment of the model, to name only a few. Although some work has been done in the area of system calibration and error correction, very little work has been done on characterizing the nature and sensitivity of the errors that cause misregistration in AR systems. This paper presents the main results of an end-to-end error analysis of an optical STHMD-based tool for surgery planning. The analysis was done with a mathematical model of the system and the main results were checked by taking measurements on a real system under controlled circumstances. The model makes it possible to analyze the sensitivity of the system-registration error to errors in each part of the system. The major results of the analysis are: (1) Even for moderate head velocities, system delay causes more registration error than all other sources combined; (2) eye tracking is probably not necessary; (3) tracker error is a significant problem both in head tracking and in system calibration; (4) the World (or reference) coordinate system adds error and should be omitted when possible; (5) computational correction of optical distortion may introduce more delay-induced registration error than the distortion error it corrects, and (6) there are many small error sources that will make submillimeter registration almost impossible in an optical STHMD system without feedback. Although this model was developed for optical STHMDs for surgical planning, many of the results apply to other HMDs as well.

Study on Aero-Optical Distortion Simulation of High Refraction Index Gradient Regions in Hypersonic Turbulent Flow

2009 ◽  
Vol 29 (11) ◽  
pp. 2952-2957 ◽  
Author(s):  
吴琳 Wu Lin ◽  
房建成 Fang Jiancheng ◽  
杨照华 Yang Zhaohua
Keyword(s):  
Turbulent Flow ◽  
Refraction Index ◽  
Optical Distortion ◽  
Index Gradient

Les effets de la refraction atmospherique sur les coordonnees tangentielles en astrometrie

1979 ◽  
Vol 89 ◽  
pp. 39-65
Author(s):  
J. Dommanget
Keyword(s):  
Optical Distortion ◽  
Relative Importance ◽  
Atmospheric Refraction ◽  
Photographic Images ◽  
Celestial Sphere

The astrometric plate reduction needs the knowledge of formulae expressing the transformation of the configuration of stellar positions on the celestial sphere into the corresponding observed figure of the photographic images on the plate. This transformation includes phenomena such as the atmospheric refraction, the optical distortion, the plate position on the instrument, etc. of which the relative importance may vary from one case to another and may lead thus to various formulae.

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