scholarly journals Multi-functional star tracker — future perspectives

10.14311/1486 ◽  
2011 ◽  
Vol 51 (6) ◽  
Author(s):  
J. Roháč ◽  
M. Řeřábek ◽  
R. Hudec
Keyword(s):  
State Of The Art ◽  
Field Of View ◽  
Star Tracker ◽  
Wide Field ◽  
Small Field ◽  
Future Perspectives ◽  
Precise Information ◽  
Current State ◽  
Fish Eye ◽  
Small Field Of View

This paper focuses on the idea of a multi-functional wide-field star tracker (WFST) and provides a description of the current state-of-the-art in this field. The idea comes from a proposal handed in to ESA at the beginning of 2011. Star trackers (STs) usually have more than one object-lens with a small Field-of-View. They provide very precise information about the attitude in space according to consecutive evaluation of star positions. Our idea of WFST will combine the functions of several instruments, e.g. ST, a horizon sensor, and an all-sky photometry camera. WFST will use a fish-eye lens. There is no comparable product on the present-day market. Nowadays, spacecraft have to carry several instruments for these applications. This increases the weight of the instrumentation and reduces the weight available for the payload.

scholarly journals Visually Guided Microassembly with Active Zooming

2006 ◽  
Vol 18 (6) ◽  
pp. 787-794
Author(s):  
Xiaodong Tao ◽  
◽  
Hyungsuck Cho ◽  
Youngjun Cho ◽  
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Depth Of Field ◽  
Wide Field ◽  
Small Field ◽  
Depth Of Focus ◽  
Large Depth ◽  
Small Depth ◽  
Wide Field Of View ◽  
Small Field Of View

Vision techniques used in automatic microassembly are limited by inherent problems such as small depth of focus and small field of view. Microassembly must, however, initially detect microparts in a wide field of view and large depth of field while maintaining high resolution. We propose microassembly using active zooming that can overcome these limitations. For a small field of view, active zooming prevents the target from getting out of the field of view during microassembly. For a small depth of focus, our proposal is based on focus measure to maintain clear target image in the field of view during microassembly. Two-step assembly thus ensures zoom microscopy maintaining a wide field of view and large depth of field initially and high resolution at the end. Peg-in-hole assembly experiments confirmed the feasibility of our proposal.

scholarly journals State of the art in the teaching of digestive ultrasound

2020 ◽  
Vol 1 (1) ◽  
pp. 71
Author(s):  
Giovanni Maconi ◽  
Mafalda Sousa
Keyword(s):  
State Of The Art ◽  
Core Competencies ◽  
Field Of View ◽  
Gastrointestinal Disorders ◽  
Small Field ◽  
Resonance Imaging ◽  
Gastrointestinal Ultrasound ◽  
Comparable Accuracy ◽  
Definition Of ◽  
Small Field Of View

Gastrointestinal ultrasound (GIUS) has been increasingly used for the management of gastrointestinal disorders due to its potentialities as a cheap, widely available and safe examination with comparable accuracy to other techniques such as Computed Tomography or Magnetic Resonance Imaging. However, some limitations have been stated to justify its underuse such as its dependency on the operator, small field of view and penetration and need of expertise. However, most of these limitations are inherent to any technique. The main problems with GIUS are lack of standardized definitions, adequate training programs and measures to assess the quality. The definition of universally applicable standardized measurements, the implementation of an internationally recognized curriculum as well as an agreed set of core competencies and the assessment of performance will hopefully overcome its potential limitations and implement its utilization universally in clinical practice.

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

Wide-field-of-view star tracker camera

1991 ◽  
Author(s):  
Isabella T. Lewis ◽  
Arno G. Ledebuhr ◽  
Timothy S. Axelrod ◽  
Joseph F. Kordas ◽  
Robert Hills
Keyword(s):  
Field Of View ◽  
Star Tracker ◽  
Wide Field ◽  
Wide Field Of View

Improvement in imaging common temporal bone pathologies at 3 T MRI: small structures benefit from a small field of view

2017 ◽  
Vol 72 (3) ◽  
pp. 267.e1-267.e12 ◽  
Author(s):  
M. Schulze ◽  
K. Reimann ◽  
A. Seeger ◽  
U. Klose ◽  
U. Ernemann ◽  
...  
Keyword(s):  
Temporal Bone ◽  
Field Of View ◽  
Small Field ◽  
Small Field Of View

scholarly journals Study on project trajectory of air-to-ground missile with strapdown seeker under multi constraints

2021 ◽  
Vol 39 (1) ◽  
pp. 141-147
Author(s):  
Junmin Zhao ◽  
Cong Nie ◽  
Guannan Chang ◽  
Meibo Lyu ◽  
Xinguo Li
Keyword(s):  
Good Condition ◽  
Field Of View ◽  
Small Field ◽  
Target Acquisition ◽  
Moving Targets ◽  
Proportional Navigation ◽  
Terminal Stage ◽  
Guidance Law ◽  
Terminal Guidance ◽  
Small Field Of View

The air-to-ground missile with strapdown seeker may have the problems, including small field of view(FOV), limited overload, and fall angle constraint. To solve the above mentioned problem, a phased guidance scheme is proposed. In this scheme, the attack trajectory is divided into the following six stages, including glided stage, fall angle constraint stage, target acquisition and adjustment stage, terminal guidance stage and blind zone stage. The glided stage is designed to increase range, the terminal fall angle is attained ahead of time at fall angle constraint stage. The aim of target acquisition and adjustment stage is to adjust the missile attitude, so that the target will fall within the FOV of the seeker. It creates good condition to capture the target for strapdown seeker. In the terminal stage, the guidance law of proportional navigation and attitude track are used to fit the needs of FOV constraint and attack accuracy. The simulation result shows that the project trajectory can solve the application of attacking moving targets for air-to-ground missile with strapdown seeker under multi constraints.

scholarly journals Brain organoids and insights on human evolution

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 760 ◽  
Author(s):  
Alysson R. Muotri
Keyword(s):  
Stem Cells ◽  
Human Brain ◽  
Human Health ◽  
Human Evolution ◽  
Pluripotent Stem Cells ◽  
Disease Modeling ◽  
State Of The Art ◽  
Future Perspectives ◽  
Promising Technique ◽  
Current State

Human brain organoids, generated from pluripotent stem cells, have emerged as a promising technique for modeling early stages of human neurodevelopment in controlled laboratory conditions. Although the applications for disease modeling in a dish have become routine, the use of these brain organoids as evolutionary tools is only now getting momentum. Here, we will review the current state of the art on the use of brain organoids from different species and the molecular and cellular insights generated from these studies. Besides, we will discuss how this model might be beneficial for human health and the limitations and future perspectives of this technology.

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