scholarly journals Functional morphology of a lobopod: case study of an onychophoran leg

2019 ◽  
Vol 6 (10) ◽  
pp. 191200 ◽  
Author(s):  
Ivo de Sena Oliveira ◽  
Andreas Kumerics ◽  
Henry Jahn ◽  
Mark Müller ◽  
Franz Pfeiffer ◽  
...  
Keyword(s):  
High Speed ◽  
Functional Anatomy ◽  
Three Dimensional ◽  
Spatial Relationship ◽  
Muscle Fibres ◽  
High Resolution Computed Tomography ◽  
Dimensional Reconstruction ◽  
Velvet Worms ◽  
Complete Set

Segmental, paired locomotory appendages are a characteristic feature of Panarthropoda—a diversified clade of moulting animals that includes onychophorans (velvet worms), tardigrades (water bears) and arthropods. While arthropods acquired a sclerotized exoskeleton and articulated limbs, onychophorans and tardigrades possess a soft body and unjointed limbs called lobopods, which they inherited from Cambrian lobopodians. To date, the origin and ancestral structure of the lobopods and their transformation into the jointed appendages are all poorly understood. We therefore combined high-resolution computed tomography with high-speed camera recordings to characterize the functional anatomy of a trunk lobopod from the onychophoran Euperipatoides rowelli . Three-dimensional reconstruction of the complete set of muscles and muscle fibres as well as non-muscular structures revealed the spatial relationship and relative volumes of the muscular, excretory, circulatory and nervous systems within the leg. Locomotory movements of individual lobopods of E. rowelli proved far more diverse than previously thought and might be governed by a complex interplay of 15 muscles, including one promotor, one remotor, one levator, one retractor, two depressors, two rotators, one flexor and two constrictors as well as muscles for stabilization and haemolymph control. We discuss the implications of our findings for understanding the evolution of locomotion in panarthropods.

Three-dimensional reconstruction of metabolic data from quantitative autoradiography of rat brain

1984 ◽  
Vol 247 (3) ◽  
pp. E412-E419 ◽  
Author(s):  
L. S. Hibbard ◽  
R. A. Hawkins
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Brain Structures ◽  
Three Dimensions ◽  
Quantitative Autoradiography ◽  
Alignment Algorithm ◽  
Computer Methods ◽  
Mathematical Properties ◽  
Dimensional Reconstruction

Quantitative autoradiography is a powerful method for studying brain function by the determination of blood flow, glucose utilization, or transport of essential nutrients. Autoradiographic images contain vast amounts of potentially useful information, but conventional analyses can practically sample the data at only a small number of points arbitrarily chosen by the experimenter to represent discrete brain structures. To use image data more fully, computer methods for its acquisition, storage, quantitative analysis, and display are required. We have developed a system of computer programs that performs these tasks and has the following features: 1) editing and analysis of single images using interactive graphics, 2) an automatic image alignment algorithm that places images in register with one another using only the mathematical properties of the images themselves, 3) the calculation of mean images from equivalent images in different experimental serial image sets, 4) the calculation of difference images (e.g., experiment-minus-control) with the option to display only differences estimated to be statistically significant, and 5) the display of serial image metabolic maps reconstructed in three dimensions using a high-speed computer graphics system.

scholarly journals A virtual diorama. Mapping archives in situ at places of cultural significance

1970 ◽  
pp. 22-36
Author(s):  
Jonathan Westin ◽  
Gunnar Almevik
Keyword(s):  
Spatial Information ◽  
Three Dimensional ◽  
Physical Space ◽  
Cultural Significance ◽  
Dimensional Reconstruction ◽  
Historical Photographs ◽  
New Applications ◽  
Archive Material

Using the wooden church of Södra Råda as a case study, this article concerns new applications of technology to contextualise and activate archive material in situ at places of cultural significance. Using a combination of augmented reality and virtual reality, we describe a process of turning historical photographs and two-dimensional reconstruction drawings into three-dimensional virtual models that can be lined up to a physical space. The leading questions for our investigation concern how archive material can be contextualised, and how the result may be made accessible in situ and contribute to place development. The result of this research suggests possibilities for using historical photographs to faithfully reconstruct lost historical spaces as three-dimensional surfaces that contextualise documentation and offer spatial information.

scholarly journals Vortex flow and cavitation in diesel injector nozzles

2008 ◽  
Vol 610 ◽  
pp. 195-215 ◽  
Author(s):  
A. ANDRIOTIS ◽  
M. GAVAISES ◽  
C. ARCOUMANIS
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Fuel Injector ◽  
Flowing Liquid ◽  
Injection Quantity ◽  
Dimensional Reconstruction ◽  
Real Size

Flow visualization as well as three-dimensional cavitating flow simulations have been employed for characterizing the formation of cavitation inside transparent replicas of fuel injector valves used in low-speed two-stroke diesel engines. The designs tested have incorporated five-hole nozzles with cylindrical as well as tapered holes operating at different fixed needle lift positions. High-speed images have revealed the formation of an unsteady vapour structure upstream of the injection holes inside the nozzle volume, which is referred to as ‘string-cavitation’. Computation of the flow distribution and combination with three-dimensional reconstruction of the location of the strings inside the nozzle volume has revealed that strings are found at the core of recirculation zones; they originate either from pre-existing cavitation sites forming at sharp corners inside the nozzle where the pressure falls below the vapour pressure of the flowing liquid, or even from suction of outside air downstream of the hole exit. Processing of the acquired images has allowed estimation of the mean location and probability of appearance of the cavitating strings in the three-dimensional space as a function of needle lift, cavitation and Reynolds number. The frequency of appearance of the strings has been correlated with the Strouhal number of the vortices developing inside the sac volume; the latter has been found to be a function of needle lift and hole shape. The presence of strings has significantly affected the flow conditions at the nozzle exit, influencing the injected spray. The cavitation structures formed inside the injection holes are significantly altered by the presence of cavitation strings and are jointly responsible for up to 10% variation in the instantaneous fuel injection quantity. Extrapolation using model predictions for real-size injectors operating at realistic injection pressures indicates that cavitation strings are expected to appear within the time scales of typical injection events, implying significant hole-to-hole and cycle-to-cycle variations during the corresponding spray development.

Large Motion Visualization and Estimation for Fluid-Structure Simulations

2015 ◽  
Author(s):  
Tzu-Sheng Shane Hsu ◽  
Timothy Fitzgerald ◽  
Vincent Phuc Nguyen ◽  
Balakumar Balachandran
Keyword(s):  
Objective Function ◽  
High Speed ◽  
Flexible Structures ◽  
Three Dimensional ◽  
Optimization Procedure ◽  
Fluid Structure Interactions ◽  
Displacement Fields ◽  
Fluid Structure ◽  
Computational Implementation

Studies of fluid-structure interactions associated with flexible structures such as flapping wings require the capture and quantification of large motions of bodies that may be opaque. As a case study, motion capture of a free flying insect is considered by using three synchronized high-speed cameras. A solid finite element (FE) representation is used as a reference body and successive snapshots in time of the displacement fields are reconstructed via an optimization procedure. One of the original aspects of this work is the formulation of an objective function and the use of shadow matching and strain-energy regularization. With this objective function, the authors penalize the shape differences between silhouettes of the captured images and the FE representation of the deformed body. A similar method with a three-dimensional voxel cloud (VC) reconstruction is also illustrated. Challenges faced in implementing the VC method are discussed and the current computational implementation will also be covered.

Measuring the angle of attack of beating insect wings: robust three-dimensional reconstruction from two-dimensional images

1997 ◽  
Vol 200 (21) ◽  
pp. 2693-2704 ◽  
Author(s):  
A Willmott ◽  
C Ellington
Keyword(s):  
High Speed ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Longitudinal Axis ◽  
Wing Motion ◽  
Insect Wings ◽  
High Speed Film ◽  
Dimensional Reconstruction ◽  
Left And Right

A robust technique for determining the angle of attack of insect wings from film of free flight has to date proved elusive. This report describes the development of two new methods ­ the Strips and Planes techniques ­ which were designed to overcome some of the limitations experienced in previous studies. The accuracy and robustness of these novel methods were tested extensively using simulated hawkmoth wing outlines generated for a realistic range of wing positions and torsion. The results were compared with those from two existing methods ­ the Symmetry and Landmarks procedures. The performance of the latter technique will be strongly species-dependent; it could not be successfully applied to hawkmoth flight because of practical difficulties in obtaining suitable landmarks. The Planes method was the least successful of the remaining techniques, especially during those phases of the wingbeat when the orientations of the two wings relative to the camera viewpoint were similar. The Symmetry and Strips methods were tested further to investigate the effects on their performance of introducing additional camber or wing motion asymmetry. The results showed clearly that the Strips method should be the technique of choice wherever the axis of wing torsion is close to the longitudinal axis of the wing. The procedure involves the experimenter matching a model wing divided into chordwise strips to the true wing outline digitized from high-speed film. The use of strips rather than the points digitized in previous studies meant that the analysis required only one wing outline to be digitized. Symmetry of motion between the left and right wings is not assumed. The implications of requiring human input to the Strips method, as opposed to the strictly numerical algorithms of the alternative techniques, are discussed. It is argued that the added flexibility that this provides in dealing with images which have typically been recorded in suboptimal conditions outweighs the introduction of an element of subjectivity. Additional observations arising from the use of the Strips analysis with high-speed video sequences of hawkmoth flight are given.

scholarly journals Three-Dimensional Reconstruction of Blood Vessels of the Human Retina by Fractal Interpolation

2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Hichem Guedri ◽  
Jihen Malek ◽  
Hafedh Belmabrouk
Keyword(s):  
Blood Vessels ◽  
3D Model ◽  
Three Dimensional ◽  
Fractal Interpolation ◽  
Human Retina ◽  
3D Image ◽  
Random Fractal ◽  
Dimensional Reconstruction ◽  
Data Points

In this work, data from two-dimensional (2D) images of the human retina were taken as a case study. First, the characteristic data points had been removed using the Douglas–Peucker (DP) method, and subsequently, more data points were added using random fractal interpolation approach, to reconstruct a three-dimensional (3D) model of the blood vessel. By visualizing the result, we can see that all the small blood vessels in the human retina are more visible and detailed. This algorithm of 3D reconstruction has the advantage of being fast with calculation time less than 40 s and also can reduce the 3D image storage level on a disk with a reduction ratio between 78% and 96.65%.

Sign in / Sign up

Export Citation Format

Share Document