scholarly journals Photogrammetric reconstruction of high-resolution surface topographies and deformable wing kinematics of tethered locusts and free-flying hoverflies

2008 ◽  
Vol 6 (33) ◽  
pp. 351-366 ◽  
Author(s):  
Simon M Walker ◽  
Adrian L.R Thomas ◽  
Graham K Taylor
Keyword(s):  
High Speed ◽  
Schistocerca Gregaria ◽  
Insect Flight ◽  
Three Dimensional ◽  
Bundle Adjustment ◽  
Angle Of Incidence ◽  
Insect Wing ◽  
Wing Kinematics ◽  
Three Dimensional Measurement ◽  
Spatio Temporal

Here, we present a suite of photogrammetric methods for reconstructing insect wing kinematics, to provide instantaneous topographic maps of the wing surface. We filmed tethered locusts ( Schistocerca gregaria ) and free-flying hoverflies ( Eristalis tenax ) using four high-speed digital video cameras. We digitized multiple natural features and marked points on the wings using manual and automated tracking. Epipolar geometry was used to identify additional points on the hoverfly wing outline which were anatomically indistinguishable. The cameras were calibrated using a bundle adjustment technique that provides an estimate of the error associated with each individual data point. The mean absolute three-dimensional measurement error was 0.11 mm for the locust and 0.03 mm for the hoverfly. The error in the angle of incidence was at worst 0.51° (s.d.) for the locust and 0.88° (s.d.) for the hoverfly. The results we present are of unprecedented spatio-temporal resolution, and represent the most detailed measurements of insect wing kinematics to date. Variable spanwise twist and camber are prominent in the wingbeats of both the species, and are of such complexity that they would not be adequately captured by lower resolution techniques. The role of spanwise twist and camber in insect flight has yet to be fully understood, and accurate insect wing kinematics such as we present here are required to be sure of making valid predictions about their aerodynamic effects.

Influence of wing kinematics on aerodynamic performance in hovering insect flight

2007 ◽  
Vol 594 ◽  
pp. 341-368 ◽  
Author(s):  
FRANK M. BOS ◽  
D. LENTINK ◽  
B. W. VAN OUDHEUSDEN ◽  
H. BIJL
Keyword(s):  
Insect Flight ◽  
Fruit Fly ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Insect Wing ◽  
Wing Kinematics ◽  
Drag Forces ◽  
Kinematic Models ◽  
Characteristic Features ◽  
Lift And Drag

The influence of different wing kinematic models on the aerodynamic performance of a hovering insect is investigated by means of two-dimensional time-dependent Navier–Stokes simulations. For this, simplified models are compared with averaged representations of the hovering fruit fly wing kinematics. With increasing complexity, a harmonic model, a Robofly model and two more-realistic fruit fly models are considered, all dynamically scaled at Re = 110. To facilitate the comparison, the parameters of the models were selected such that their mean quasi-steady lift coefficients were matched. Details of the vortex dynamics, as well as the resulting lift and drag forces, were studied.The simulation results reveal that the fruit fly wing kinematics result in forces that differ significantly from those resulting from the simplified wing kinematic models. In addition, light is shed on the effect of different characteristic features of the insect wing motion. The angle of attack variation used by fruit flies increases aerodynamic performance, whereas the deviation is probably used for levelling the forces over the cycle.

REAL-TIME PHOTOGRAMMETRY AT THE DIGITAL PHOTOGRAMMETRIC STATION (DIPS) OF ETH ZURICH

1987 ◽  
Vol 41 (2) ◽  
pp. 181-199 ◽  
Author(s):  
Armin W. Gruen ◽  
Horst A. Beyer
Keyword(s):  
Real Time ◽  
Three Dimensional ◽  
Development Program ◽  
Bundle Adjustment ◽  
Object Distance ◽  
Federal Institute ◽  
Adjustment Program ◽  
Three Dimensional Measurement ◽  
Institute Of Technology ◽  
Processing Steps

Real-time photogrammetry (RTP) is a non-contact three-dimensional measurement technique with a response time of one video cycle. As part of a research and development program for digital and real-time photogrammetry, the Institute of Geodesy and Photogrammety at the Swiss Federal Institute of Technology, Zurich, Switzerland, has established the Digital Photogrammetric Station (DIPS). The hardware and software of this development system is explained. Hardware aspects of solid-state cameras relevant to camera calibration for RTP are discussed. An off-line bundle adjustment program with additional parameters has been installed. An initial calibration and point positioning test using this program and existing image processing algorithms has been performed. The processing steps and results are analyzed. Accuracies, as computed from object space check points, in planimetry of 1:5000 or 0.09 pixel pitch, in depth of 0.08%c of object distance, have been achieved.

scholarly journals Tomographic particle image velocimetry of desert locust wakes: instantaneous volumes combine to reveal hidden vortex elements and rapid wake deformation

2012 ◽  
Vol 9 (77) ◽  
pp. 3378-3386 ◽  
Author(s):  
Richard J. Bomphrey ◽  
Per Henningsson ◽  
Dirk Michaelis ◽  
David Hollis
Keyword(s):  
Particle Image Velocimetry ◽  
High Speed ◽  
Particle Image ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Flow Fields ◽  
Diagnostic Methods ◽  
Tomographic Particle Image Velocimetry ◽  
Image Velocimetry ◽  
Spatio Temporal

Aerodynamic structures generated by animals in flight are unstable and complex. Recent progress in quantitative flow visualization has advanced our understanding of animal aerodynamics, but measurements have hitherto been limited to flow velocities at a plane through the wake. We applied an emergent, high-speed, volumetric fluid imaging technique (tomographic particle image velocimetry) to examine segments of the wake of desert locusts, capturing fully three-dimensional instantaneous flow fields. We used those flow fields to characterize the aerodynamic footprint in unprecedented detail and revealed previously unseen wake elements that would have gone undetected by two-dimensional or stereo-imaging technology. Vortex iso-surface topographies show the spatio-temporal signature of aerodynamic force generation manifest in the wake of locusts, and expose the extent to which animal wakes can deform, potentially leading to unreliable calculations of lift and thrust when using conventional diagnostic methods. We discuss implications for experimental design and analysis as volumetric flow imaging becomes more widespread.

THE PARALLEL CRANK-ROCKER FLAPPING MECHANISM: AN INSECT-INSPIRED DESIGN FOR MICRO AIR VEHICLES

2007 ◽  
Vol 04 (04) ◽  
pp. 625-643 ◽  
Author(s):  
ANDREW T. CONN ◽  
STUART C. BURGESS ◽  
SENG LING CHUNG
Keyword(s):  
High Speed ◽  
Beat Frequency ◽  
Unsteady Aerodynamics ◽  
Micro Air Vehicles ◽  
Indoor Environments ◽  
Insect Wing ◽  
Wing Kinematics ◽  
System A ◽  
Flying Robot ◽  
Flapping Mechanism

This paper presents a novel micro air vehicle (MAV) design that seeks to reproduce the unsteady aerodynamics of insects in their natural flight. The challenge of developing an MAV capable of hovering and maneuvering through indoor environments has led to bio-inspired flapping propulsion being considered instead of conventional fixed or rotary winged flight. Insects greatly outperform these conventional flight platforms by exploiting several unsteady aerodynamic phenomena. Therefore, reproducing insect aerodynamics by mimicking their complex wing kinematics with a miniature flying robot has significant benefits in terms of flight performance. However, insect wing kinematics are extremely complex and replicating them requires optimal design of the actuation and flapping mechanism system. A novel flapping mechanism based on parallel crank-rockers has been designed that accurately reproduces the wing kinematics employed by insects and also offers control for flight maneuvers. The mechanism has been developed into an experimental prototype with MAV scale wings (75 mm long). High-speed camera footage of the non-airborne prototype showed that its wing kinematics closely matched desired values, but that the wing beat frequency of 5.6 Hz was below the predicted value of 15 Hz. Aerodynamic testing of the prototype in hovering conditions was completed using a load cell and the mean lift force at the maximum power output was measured to be 23.8 mN.

Three-dimensional measurement by high-speed line-field Fourier-domain optical coherence tomography in vivo

2006 ◽  
Author(s):  
Shuichi Makita ◽  
Yosifumi Nakamura ◽  
Yoshiaki Yasuno ◽  
Takashi Endo ◽  
Masahiro Yamanari ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
High Speed ◽  
Three Dimensional ◽  
Fourier Domain ◽  
Optical Coherence ◽  
Line Field ◽  
Dimensional Measurement ◽  
Three Dimensional Measurement

Structured Light Field Generated by Two Projectors for High-Speed Three Dimensional Measurement

2016 ◽  
Vol 28 (4) ◽  
pp. 523-532 ◽  
Author(s):  
Akihiro Obara ◽  
◽  
Xu Yang ◽  
Hiromasa Oku ◽  
Keyword(s):  
High Speed ◽  
Light Field ◽  
Stereo Matching ◽  
Structured Light ◽  
Three Dimensional ◽  
Depth Estimation ◽  
Image Features ◽  
Depth Information ◽  
Speed Tracking ◽  
Three Dimensional Measurement

[abstFig src='/00280004/10.jpg' width='300' text='Concept of SLF generated by two projectors' ] Triangulation is commonly used to restore 3D scenes, but its frame of less than 30 fps due to time-consuming stereo-matching is an obstacle for applications requiring that results be fed back in real time. The structured light field (SLF) our group proposed previously reduced the amount of calculation in 3D restoration, realizing high-speed measurement. Specifically, the SLF estimates depth information by projecting information on distance directly to a target. The SLF synthesized as reported, however, presents difficulty in extracting image features for depth estimation. In this paper, we propose synthesizing the SLF using two projectors with a certain layout. Our proposed SLF’s basic properties are based on an optical model. We evaluated the SLF’s performance using a prototype we developed and applied to the high-speed depth estimation of a target moving randomly at a speed of 1000 Hz. We demonstrate the target’s high-speed tracking based on high-speed depth information feedback.

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