Rotating Camera System for In-Flight Propeller Blade Deformation Measurements

2016 ◽  
pp. 619-628
Author(s):  
Fritz Boden ◽  
Bolesław Stasicki
Keyword(s):  
Propeller Blade ◽  
Camera System ◽  
Rotating Camera ◽  
Deformation Measurements

In-flight measurements of propeller blade deformation on a VUT100 cobra aeroplane using a co-rotating camera system

2016 ◽  
Vol 27 (7) ◽  
pp. 074013 ◽  
Author(s):  
F Boden ◽  
B Stasicki ◽  
M Szypuła ◽  
P Ružička ◽  
Z Tvrdik ◽  
...  
Keyword(s):  
Propeller Blade ◽  
Camera System ◽  
Rotating Camera ◽  
Flight Measurements

scholarly journals 7.4 - Optical Rotor-Blade Deformation Measurements using a Rotating Camera

2018 ◽  
Author(s):  
F. Boden ◽  
B. Stasicki ◽  
K. Ludwikowski
Keyword(s):  
Rotor Blade ◽  
Rotating Camera ◽  
Deformation Measurements

Precise on-line Measurement of Lattice Vectors

1990 ◽  
Vol 48 (1) ◽  
pp. 530-531
Author(s):  
W.J. de Ruijter ◽  
Sharma Renu
Keyword(s):  
Electron Microscope ◽  
Measurement Errors ◽  
Dynamic Range ◽  
Structural Information ◽  
Statistical Parameter ◽  
Systematic Errors ◽  
Geometric Distortion ◽  
Crystal Silicon ◽  
Camera System ◽  
On Line

Established methods for measurement of lattice spacings and angles of crystalline materials include x-ray diffraction, microdiffraction and HREM imaging. Structural information from HREM images is normally obtained off-line with the traveling table microscope or by the optical diffractogram technique. We present a new method for precise measurement of lattice vectors from HREM images using an on-line computer connected to the electron microscope. It has already been established that an image of crystalline material can be represented by a finite number of sinusoids. The amplitude and the phase of these sinusoids are affected by the microscope transfer characteristics, which are strongly influenced by the settings of defocus, astigmatism and beam alignment. However, the frequency of each sinusoid is solely a function of overall magnification and periodicities present in the specimen. After proper calibration of the overall magnification, lattice vectors can be measured unambiguously from HREM images.Measurement of lattice vectors is a statistical parameter estimation problem which is similar to amplitude, phase and frequency estimation of sinusoids in 1-dimensional signals as encountered, for example, in radar, sonar and telecommunications. It is important to properly model the observations, the systematic errors and the non-systematic errors. The observations are modelled as a sum of (2-dimensional) sinusoids. In the present study the components of the frequency vector of the sinusoids are the only parameters of interest. Non-systematic errors in recorded electron images are described as white Gaussian noise. The most important systematic error is geometric distortion. Lattice vectors are measured using a two step procedure. First a coarse search is obtained using a Fast Fourier Transform on an image section of interest. Prior to Fourier transformation the image section is multiplied with a window, which gradually falls off to zero at the edges. The user indicates interactively the periodicities of interest by selecting spots in the digital diffractogram. A fine search for each selected frequency is implemented using a bilinear interpolation, which is dependent on the window function. It is possible to refine the estimation even further using a non-linear least squares estimation. The first two steps provide the proper starting values for the numerical minimization (e.g. Gauss-Newton). This third step increases the precision with 30% to the highest theoretically attainable (Cramer and Rao Lower Bound). In the present studies we use a Gatan 622 TV camera attached to the JEM 4000EX electron microscope. Image analysis is implemented on a Micro VAX II computer equipped with a powerful array processor and real time image processing hardware. The typical precision, as defined by the standard deviation of the distribution of measurement errors, is found to be <0.003Å measured on single crystal silicon and <0.02Å measured on small (10-30Å) specimen areas. These values are ×10 times larger than predicted by theory. Furthermore, the measured precision is observed to be independent on signal-to-noise ratio (determined by the number of averaged TV frames). Obviously, the precision is restricted by geometric distortion mainly caused by the TV camera. For this reason, we are replacing the Gatan 622 TV camera with a modern high-grade CCD-based camera system. Such a system not only has negligible geometric distortion, but also high dynamic range (>10,000) and high resolution (1024x1024 pixels). The geometric distortion of the projector lenses can be measured, and corrected through re-sampling of the digitized image.

Human Factors Evaluation of 360 Panoramic View Camera System for Ground Vehicle

2007 ◽  
Author(s):  
Cheng Li Wei ◽  
Ang Cher Wee ◽  
Chan Wai Herng ◽  
Ying Meng Fai
Keyword(s):  
Human Factors ◽  
Panoramic View ◽  
Camera System ◽  
Ground Vehicle

Deformation Measurements by Echocardiography versus Late Enhancement Magnetic Resonance Imaging in Patients with Coronary Artery Disease

2012 ◽  
Vol 8 (2) ◽  
pp. 101
Author(s):  
Brage H Amundsen ◽  
Anders Thorstensen ◽  
Asbjørn Støylen ◽  
◽  
◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Magnetic Resonance ◽  
Late Enhancement ◽  
High Temporal Resolution ◽  
Resonance Imaging ◽  
Deformation Imaging ◽  
Artery Disease ◽  
Deformation Measurements

The aim of this article is to discuss the present and future potential of deformation imaging by echocardiography and scar visualisation by magnetic resonance imaging (MRI) in patients with coronary artery disease (CAD). The two methods are clearly different: one is concerned with function, the other with morphology. Echocardiography, with its versatility of methods and high applicability, will continue to be the workhorse in cardiac imaging of patients with CAD. Important additional information can be extracted from deformation imaging methods, especially due to the high temporal resolution in tissue Doppler. Deformation measurements in 3D images are still limited by their lower resolution compared with 2D but will continue to improve. The standardisation of image analysis and the collaboration within the echocardiographic community to conduct larger studies will be important tasks in the attempt to establish evidence for the new methods. Late enhancement MRI is a method with unique properties and will continue to be an important alternative in selected patients and settings, as well as an invaluable research tool.

An Optoelectronic System for Real-Time Surface Deformation Measurements

Vestnik MEI ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 101-108
Author(s):  
Anton Yu. Poroykov ◽  
◽  
Konstantin M. Lapitskiy ◽  
Keyword(s):  
Real Time ◽  
Surface Deformation ◽  
Optoelectronic System ◽  
Deformation Measurements
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