Sketch Beautification in Air

2015 ◽  
Author(s):  
Nianteng Feng ◽  
Prakhar Jaiswal ◽  
Rahul Rai
Keyword(s):  
Power Law ◽  
Leap Motion ◽  
Depth Sensing ◽  
Learning Time ◽  
Hand Trajectory ◽  
Contact Depth ◽  
Novice Users ◽  
Computer Based ◽  
Sketching Interface

Computer-based sketches are geometrically accurate and can be rendered formally. However, existing interfaces of sketching are complex, non-intuitive, and require considerable learning time for novice users. In our work, we aim to develop an intuitive gesture-based sketching interface that provide designers with the freedom of sketching in the air, without touching or wearing any physical device. With our novel sketching system, users could draw letters, symbols, and drawings using non-contact depth-sensing cameras, such as SoftKinetic and Leap Motion. The system records user’s hand trajectory as raw sketch. The sketch is analyzed and beautified to express user’s intent more accurately. Beautification process involves segmenting the sketch into different segments and rebuilding it to form a more beautified sketch. In this process, we use 2/3rd power law which provides novel kinematic features of segments and helps to improve beautification. Our results show encouraging performance for a broad range of writing styles and drawings in the air.

On the Discretization of the Power-Law Hemolysis Model

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Mohammad M. Faghih ◽  
Ahmed Islam ◽  
M. Keith Sharp
Keyword(s):  
Fluid Dynamics ◽  
Power Law ◽  
Velocity Fields ◽  
Radial Expansion ◽  
Complex Flows ◽  
Cfd Simulations ◽  
Large Exponent ◽  
Computer Based ◽  
Computational Fluid Dynamics Cfd ◽  
Simple Flows

Abstract Flow-induced hemolysis remains a concern for blood-contacting devices, and computer-based prediction of hemolysis could facilitate faster and more economical refinement of such devices. While evaluation of convergence of velocity fields obtained by computational fluid dynamics (CFD) simulations has become conventional, convergence of hemolysis calculations is also essential. In this paper, convergence of the power-law hemolysis model is compared for simple flows, including pathlines with exponentially increasing and decreasing stress, in gradually expanding and contracting Couette flows, in a sudden radial expansion and in the Food and Drug Administration (FDA) channel. In the exponential cases, convergence along a pathline required from one to tens of thousands of timesteps, depending on the exponent. Greater timesteps were required for rapidly increasing (large exponent) stress and for rapidly decreasing (small exponent) stress. Example pathlines in the Couette flows could be fit with exponential curves, and convergence behavior followed the trends identified from the exponential cases. More complex flows, such as in the radial expansion and the FDA channel, increase the likelihood of encountering problematic pathlines. For the exponential cases, comparison of converged hemolysis values with analytical solutions demonstrated that the error of the converged solution may exceed 10% for both rapidly decreasing and rapidly increasing stress.

Close range depth sensing cameras for virtual reality based hand rehabilitation

2014 ◽  
Vol 8 (3) ◽  
pp. 138-149 ◽  
Author(s):  
Darryl Charles ◽  
Katy Pedlow ◽  
Suzanne McDonough ◽  
Ka Shek ◽  
Therese Charles
Keyword(s):  
Virtual Reality ◽  
Young Patients ◽  
Leap Motion ◽  
Three Dimension ◽  
Hand Rehabilitation ◽  
Depth Sensing ◽  
Content Type ◽  
Health And Social Care ◽  
Close Range ◽  
Rehabilitation Tasks

Purpose – The Leap Motion represents a new generation of depth sensing cameras designed for close range tracking of hands and fingers, operating with minimal latency and high spatial precision (0.01 mm). The purpose of this paper is to develop virtual reality (VR) simulations of three well-known hand-based rehabilitation tasks using a commercial game engine and utilising a Leap camera as the primary mode of interaction. The authors present results from an initial evaluation by professional clinicians of these VR simulations for use in their hand and finger physical therapy practice. Design/methodology/approach – A cross-disciplinary team of researchers collaborated with a local software company to create three dimension interactive simulations of three hand focused rehabilitation tasks: Cotton Balls, Stacking Blocks, and the Nine Hole Peg Test. These simulations were presented to a group of eight physiotherapists and occupational therapists (n=8) based in the Regional Acquired Brain Injury Unit, Belfast Health, and Social Care Trust for evaluation. After induction, the clinicians attempted the tasks presented and provided feedback by filling out a questionnaire. Findings – Results from questionnaires (using a Likert scale 1-7, where 1 was the most favourable response) revealed a positive response to the simulations with an overall mean score across all questions equal to 2.59. Clinicians indicated that the system contained tasks that were easy to understand (mean score 1.88), and though it took several attempts to become competent, they predicted that they would improve with practice (mean score 2.25). In general, clinicians thought the prototypes provided a good illustration of the tasks required in their practice (mean score 2.38) and that patients would likely be motivated to use the system (mean score 2.38), especially young patients (mean score 1.63), and in the home environment (mean score 2.5). Originality/value – Cameras offer an unobtrusive and low maintenance approach to tracking user motion in VR therapy in comparison to methods based on wearable technologies. This paper presents positive results from an evaluation of the new Leap Motion camera for input control of VR simulations or games. This mode of interaction provides a low cost, easy to use, high-resolution system for tracking fingers and hands, and has great potential for home-based physical therapies, particularly for young people.

Fatigue at Nanoscale: An Integrated Stiffness and Depth Sensing Approach to Investigate the Mechanisms of Failure in Diamondlike Carbon Film

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
R. Ahmed ◽  
Y. Q. Fu ◽  
N. H. Faisal
Keyword(s):  
Failure Modes ◽  
Low Cycle Fatigue ◽  
Contact Stiffness ◽  
Depth Sensing ◽  
Load Range ◽  
Appreciable Change ◽  
Contact Depth ◽  
Substrate Interface ◽  
Diamondlike Carbon ◽  
Film Substrate

Nanoscale impact fatigue tests were conducted to comprehend the relative fatigue performance and failure modes of 100 nm thick diamondlike carbon (DLC) film deposited on a 4 in. diameter Si (100) wafer of 500 μm thickness. The nanofatigue tests were performed using a calibrated TriboIndenter equipped with Berkovich indenter in the load range of 300–1000 μN. Each test was conducted for a total of 999 fatigue cycles (a low cycle fatigue test). Contact depth in this load range varied from 10 to 30 nm. An integrated contact stiffness and depth sensing approach was adapted to understand the mechanisms of fatigue failure. The contact depth and stiffness data indicated some peculiar characteristics, which provided some insights into the mechanisms of cohesive and adhesive failure in thin films. Based on the contact stiffness and depth data, and surface observations of failed DLC films using atomic force microscope and scanning probe microscopy, a five-stage failure mechanism is proposed. The failure of films starts from cohesive failure via cracks perpendicular to the film/substrate interface, resulting in a decrease in contact depth with number of fatigue cycles and no appreciable change in contact stiffness. This is followed by film delamination at the film/substrate interface and release of elastic stored energy (residual stress) resulting in an increase in contact stiffness. Finally, as the film breaks apart the contact stiffness decreases with a corresponding increase in contact depth.

Analysis of power law assumptions for short-period comets and Kuiper bodies

1999 ◽  
Vol 173 ◽  
pp. 289-293 ◽  
Author(s):  
J.R. Donnison ◽  
L.I. Pettit
Keyword(s):  
Power Law ◽  
Pareto Distribution ◽  
Limited Data ◽  
Short Period ◽  
Probability Plots ◽  
Exponential Probability

AbstractA Pareto distribution was used to model the magnitude data for short-period comets up to 1988. It was found using exponential probability plots that the brightness did not vary with period and that the cut-off point previously adopted can be supported statistically. Examination of the diameters of Trans-Neptunian bodies showed that a power law does not adequately fit the limited data available.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

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