Photogrammetric Investigation of the Flying Shape of Spinnakers in a Twisted Flow Wind Tunnel

2009 ◽  
Author(s):  
Kai Graf ◽  
Olaf Müller
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
High Resolution ◽  
Wind Tunnel ◽  
Wind Velocity ◽  
Digital Cameras ◽  
Pattern Recognition Methods ◽  
Twisted Flow ◽  
High Resolution Images ◽  
The Impact

This paper describes a method for the acquisition of the flying shape of spinnakers in a twisted flow wind tunnel. The method is based on photogrammetry. A set of digital cameras is used to obtain high resolution images of the spinnaker from different viewing angles. The images are post-processed using image-processing tools, pattern recognition methods and finally the photogrammetry algorithm. Results are shown comparing design versus flying shape of the spinnaker and the impact of wind velocity and wind twist on the flying shape. Finally some common rules for optimum spinnaker trimming are investigated and examined.

Splash formation by spherical drops

2001 ◽  
Vol 427 ◽  
pp. 73-105 ◽  
Author(s):  
LIOW JONG LENG
Keyword(s):  
High Resolution ◽  
Quantitative Data ◽  
Water Surface ◽  
High Speed ◽  
Scaling Laws ◽  
Capillary Wave ◽  
Water Drop ◽  
Qualitative And Quantitative ◽  
High Resolution Images ◽  
The Impact

The impact of a spherical water drop onto a water surface has been studied experimentally with the aid of a 35 mm drum camera giving high-resolution images that provided qualitative and quantitative data on the phenomena. Scaling laws for the time to reach maximum cavity sizes have been derived and provide a good fit to the experimental results. Transitions between the regimes for coalescence-only, the formation of a high-speed jet and bubble entrapment have been delineated. The high-speed jet was found to occur without bubble entrapment. This was caused by the rapid retraction of the trough formed by a capillary wave converging to the centre of the cavity base. The converging capillary wave has a profile similar to a Crapper wave. A plot showing the different regimes of cavity and impact drop behaviour in the Weber–Froude number-plane has been constructed for Fr and We less than 1000.

scholarly journals Intercomparison of Unmanned Aircraftborne and Mobile Mesonet Atmospheric Sensors

2016 ◽  
Vol 33 (8) ◽  
pp. 1569-1582 ◽  
Author(s):  
Adam L. Houston ◽  
Roger J. Laurence ◽  
Tevis W. Nichols ◽  
Sean Waugh ◽  
Brian Argrow ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
Vertical Velocity ◽  
Humidity Sensor ◽  
Heavy Precipitation ◽  
Unmanned Aircraft ◽  
Sensor Performance ◽  
The Tempest ◽  
Aircraft System ◽  
The Impact

AbstractResults are presented from an intercomparison of temperature, humidity, and wind velocity sensors of the Tempest unmanned aircraft system (UAS) and the National Severe Storms Laboratory (NSSL) mobile mesonet (NSSL-MM). Contemporaneous evaluation of sensor performance was facilitated by mounting the Tempest wing with attached sensors to the NSSL-MM instrument rack such that the Tempest and NSSL-MM sensors could collect observations within a nearly identical airstream. This intercomparison was complemented by wind tunnel simulations designed to evaluate the impact of the mobile mesonet vehicle on the observed wind velocity.The intercomparison revealed strong correspondence between the temperature and relative humidity (RH) data collected by the Tempest and the NSSL-MM with differences generally within sensor accuracies. Larger RH differences were noted in the presence of heavy precipitation; however, despite the exposure of the Tempest temperature and humidity sensor to the airstream, there was no evidence of wet bulbing within precipitation. Wind tunnel simulations revealed that the simulated winds at the location of the NSSL-MM wind monitor were ~4% larger than the expected winds due to the acceleration of the flow over the vehicle. Simulated vertical velocity exceeded 1 m s−1 for tunnel inlet speeds typical of a vehicle moving at highway speeds. However, the theoretical noncosine reduction in winds that should result from the impact of vertical velocity on the laterally mounted wind monitor was found to be negligible across the simulations. Comparison of the simulated and observed results indicates a close correspondence, provided the crosswind component of the flow is small.

scholarly journals Imaging Large Tissue Samples at High Resolution

2000 ◽  
Vol 8 (7) ◽  
pp. 31-31
Author(s):  
Robert Meyer
Keyword(s):  
High Resolution ◽  
Fundamental Problem ◽  
Digital Cameras ◽  
Image Capture ◽  
Tissue Samples ◽  
Video Cameras ◽  
Conventional Technology ◽  
High Resolution Images ◽  
Display Resolution ◽  
Frame Grabber

To those scientists and researchers who use microscopes with video or digital cameras for the purpose of capture and display, there has always existed a fundamental problem, namely, imaging large tissue samples at high resolution.For some time, conventional technology has allowed video cameras to be attached to microscopes. The signal generated by these cameras can be captured and saved to a computer's hard drive using a frame grabber. A typical image capture and display resolution is 640 by 480 (307,200) pixels. Although the image produced is ‘good’, it is by no means considered ‘high resolution’. For the sake of discussion, ‘high resolution’ is defined as greater than 1,000 x 1,000 (1,000,000) pixels. High resolution images are essential for medical applications. Today's modern digital cameras can meet or exceed this value. The human eye, if compared to these examples, has the equivalent resolution of greater than 5,000 x 5,000 (25,000,000) pixels.

An integral design strategy combining optical system and image processing to obtain high resolution images

2016 ◽  
Author(s):  
Jiaoyang Wang ◽  
Lin Wang ◽  
Ying Yang ◽  
Rui Gong ◽  
Xiaopeng Shao ◽  
...  
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
Optical System ◽  
Design Strategy ◽  
High Resolution Images

A new automatic and interactive tree ring measurement system based on a line scan camera

1992 ◽  
Vol 68 (1) ◽  
pp. 138-141 ◽  
Author(s):  
Régent Guay ◽  
Réjean Gagnon ◽  
Hubert Morin
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
Tree Ring ◽  
Measurement System ◽  
Analysis Techniques ◽  
Image Processing And Analysis ◽  
Line Scan ◽  
Computerized Image Processing ◽  
On Line ◽  
High Resolution Images

A new automatic tree ring measurement system which uses computerized image processing and analysis techniques is presented. It is based on a line scan camera instead of a conventional TV camera so it can give high resolution images over long paths (many centimeters). On-line ring validation is possible by comparison with those on other radii. Also, the system is highly interactive so its decisions can be modified by the operator.

Processing of high-resolution images of irradiated ceramics

1993 ◽  
Vol 51 ◽  
pp. 210-211
Author(s):  
M.E. Lewis ◽  
L.C. Qin ◽  
A.N. Sreeram ◽  
L.W. Hobbs
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
Mathematical Morphology ◽  
Underlying Structure ◽  
Scale Morphology ◽  
Ordered Structures ◽  
Image Processing And Analysis ◽  
High Resolution Images ◽  
Lead Pyrophosphate ◽  
The Relationship

Mathematical morphology as an image processing and analysis tools is both a science and an art. The theory of mathematical morphology is rooted in topology, where a set-theoretic framework is the basis of binary morphology. Gray-scale morphology is an extension into the space of functions. This rigorous formulation has provided powerful transformations, operating directly on the information content of an image. However, it is up to the investigator’s creativity to devise the appropriate criteria for each problem at hand.The main focus of the present study is the analysis of image contrast and the relationship with the underlying structure of the material. Image processing and analysis methods based on mathematical morphology were applied to high resolution micrographs of irradiated ceramics: electronirradiated tridymite and ion-irradiated lead pyrophosphate single crystal.The interesting feature of these images is the presence of periodic, aperiodic and partially ordered structures, Fig.s la and 2a.

scholarly journals Applying Pattern Recognition to High-Resolution Images to Determine Cellular Signaling Status

2017 ◽  
Vol 16 (6) ◽  
pp. 438-446 ◽  
Author(s):  
Michael F. Lohrer ◽  
Darrin M. Hanna ◽  
Yang Liu ◽  
Kang-Hsin Wang ◽  
Fu-Tong Liu ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
High Resolution ◽  
Cellular Signaling ◽  
High Resolution Images
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