scholarly journals Selection of Key Frames for 3D Reconstruction in Real Time

Algorithms ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 303
Author(s):  
Alan Koschel ◽  
Christoph Müller ◽  
Alexander Reiterer
Keyword(s):  
3D Reconstruction ◽  
Real Time ◽  
Inertial Sensors ◽  
Motion Blur ◽  
Fast Fourier Transformation ◽  
3D Data ◽  
Complex Image ◽  
Key Frames ◽  
Required Quality ◽  
Selection Of

Cameras play a prominent role in the context of 3D data, as they can be designed to be very cheap and small and can therefore be used in many 3D reconstruction systems. Typical cameras capture video at 20 to 60 frames per second, resulting in a high number of frames to select from for 3D reconstruction. Many frames are unsuited for reconstruction as they suffer from motion blur or show too little variation compared to other frames. The camera used within this work has built-in inertial sensors. What if one could use the built-in inertial sensors to select a set of key frames well-suited for 3D reconstruction, free from motion blur and redundancy, in real time? A random forest classifier (RF) is trained by inertial data to determine frames without motion blur and to reduce redundancy. Frames are analyzed by the fast Fourier transformation and Lucas–Kanade method to detect motion blur and moving features in frames to label those correctly to train the RF. We achieve a classifier that omits successfully redundant frames and preserves frames with the required quality but exhibits an unsatisfied performance with respect to ideal frames. A 3D reconstruction by Meshroom shows a better result with selected key frames by the classifier. By extracting frames from video, one can comfortably scan objects and scenes without taking single pictures. Our proposed method automatically extracts the best frames in real time without using complex image-processing algorithms.

Tobacco’s Appeal to the Senses and the Early Modern Smoker’s Still Life

2020 ◽  
pp. 123-150
Author(s):  
Julia Saviello
Keyword(s):  
Still Life ◽  
Sense Data ◽  
Complex Image ◽  
Starting Point ◽  
Depth Analysis ◽  
Tobacco Pipes ◽  
Five Senses ◽  
The Senses ◽  
Cut Tobacco ◽  
Selection Of

Smell and taste – of the five senses these are the two most strongly stimulated by smoking tobacco. The article presents an in-depth analysis of the reflection of both these forms of sensory perception in textual and visual sources concerning the early consumption of the herb. In a first step, tobacco’s changing reception, first as medicine and then as stimulant, is traced through the years of its increasing distribution in Europe, starting in the middle of the 16th century. As this overview reveals, at that time the still little known substance gave rise to new forms of sense perception. Following recent studies on smell and gustation, which have stressed the need to take into account the interactions between these senses, the article probes the manifold stimulation of the senses by tobacco with reference to allegorical representations and genre scenes addressing the five senses. The smoking of tobacco was thematized in both of these art forms as a means of visualizing either smell or taste. Yet, these depictions show no indication of any deliberate engagement with the exchange of sense data between mouth and nose. The question posed at the end of this paper is whether this holds true also for early smoker’s still lifes. In the so-called toebakjes or rookertjes, a subgenre of stilllife painting that, like tobacco, was still a novelty at the beginning of the 17th century, various smoking paraphernalia – such as rolled or cut tobacco, pipes and tins – are arrayed with various kinds of foods and drinks. Finally, the article addresses a selection of such smoker’s still lifes, using the toebakje by Pieter Claesz., probably the first of its kind, as a starting point and the work by Georg Flegel as a comparative example. Through their selection of objects, both offer a complex image of how tobacco engages different senses.

Network Selection in Wireless Heterogeneous Environment Based on Available Bandwidth Estimation

2019 ◽  
Vol 12 ◽  
Author(s):  
Kiran Ahuja ◽  
Brahmjit Singh ◽  
Rajesh Khanna
Keyword(s):  
Real Time ◽  
Estimation Error ◽  
Network Selection ◽  
Bandwidth Estimation ◽  
Heterogeneous Environment ◽  
Bootstrap Approximation ◽  
Available Bandwidth ◽  
Internet Connection ◽  
Available Bandwidth Estimation ◽  
Selection Of

Background: With the availability of multiple options in wireless network simultaneously, Always Best Connected (ABC) requires dynamic selection of the best network and access technologies. Objective: In this paper, a novel dynamic access network selection algorithm based on the real time is proposed. The available bandwidth (ABW) of each network is required to be estimated to solve the network selection problem. Method: Proposed algorithm estimates available bandwidth by taking averages, peaks, low points and bootstrap approximation for network selection. It monitors real-time internet connection and resolves the selection issue in internet connection. The proposed algorithm is capable of adapting to prevailing network conditions in heterogeneous environment of 2G, 3G and WLAN networks without user intervention. It is implemented in temporal and spatial domains to check its robustness. Estimation error, overhead, estimation time with the varying size of traffic and reliability are used as the performance metrics. Results: Through numerical results, it is shown that the proposed algorithm’s ABW estimation based on bootstrap approximation gives improved performance in terms of estimation error (less than 20%), overhead (varies from 0.03% to 83%) and reliability (approx. 99%) with respect to existing techniques. Conclusion: Our proposed methodology of network selection criterion estimates the available bandwidth by taking averages, peaks, and low points and bootstrap approximation method (standard deviation) for the selection of network in the wireless heterogeneous environment. It monitors real-time internet connection and resolves internet connections selection issue. All the real-time usage and test results demonstrate the productivity and adequacy of available bandwidth estimation with bootstrap approximation as a practical solution for consistent correspondence among heterogeneous wireless networks by precise network selection for multimedia services.

scholarly journals Evaluation of Optimal Vibrotactile Feedback for Force-Controlled Upper Limb Myoelectric Prostheses

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5209 ◽  
Author(s):  
Andrea Gonzalez-Rodriguez ◽  
Jose L. Ramon ◽  
Vicente Morell ◽  
Gabriel J. Garcia ◽  
Jorge Pomares ◽  
...  
Keyword(s):  
Real Time ◽  
Upper Limb ◽  
Closed Loop ◽  
Fine Tuning ◽  
Vibrotactile Feedback ◽  
Loop Control ◽  
Myoelectric Prostheses ◽  
Amplitude Level ◽  
Real Time Application ◽  
Selection Of

The main goal of this study is to evaluate how to optimally select the best vibrotactile pattern to be used in a closed loop control of upper limb myoelectric prostheses as a feedback of the exerted force. To that end, we assessed both the selection of actuation patterns and the effects of the selection of frequency and amplitude parameters to discriminate between different feedback levels. A single vibrotactile actuator has been used to deliver the vibrations to subjects participating in the experiments. The results show no difference between pattern shapes in terms of feedback perception. Similarly, changes in amplitude level do not reflect significant improvement compared to changes in frequency. However, decreasing the number of feedback levels increases the accuracy of feedback perception and subject-specific variations are high for particular participants, showing that a fine-tuning of the parameters is necessary in a real-time application to upper limb prosthetics. In future works, the effects of training, location, and number of actuators will be assessed. This optimized selection will be tested in a real-time proportional myocontrol of a prosthetic hand.

Real-time Approximation of Photometric Polygonal Lights

2020 ◽  
Vol 3 (1) ◽  
pp. 1-18
Author(s):  
Christian Luksch ◽  
Lukas Prost ◽  
Michael Wimmer
Keyword(s):  
Real Time ◽  
Specular Reflection ◽  
Near Field ◽  
Measurement Data ◽  
Data Sets ◽  
Photometric Measurement ◽  
Integration Technique ◽  
Time Approximation ◽  
Light Emitter ◽  
Selection Of

We present a real-time rendering technique for photometric polygonal lights. Our method uses a numerical integration technique based on a triangulation to calculate noise-free diffuse shading. We include a dynamic point in the triangulation that provides a continuous near-field illumination resembling the shape of the light emitter and its characteristics. We evaluate the accuracy of our approach with a diverse selection of photometric measurement data sets in a comprehensive benchmark framework. Furthermore, we provide an extension for specular reflection on surfaces with arbitrary roughness that facilitates the use of existing real-time shading techniques. Our technique is easy to integrate into real-time rendering systems and extends the range of possible applications with photometric area lights.

scholarly journals Real-Time Compression for Tactile Internet Data Streams

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1924
Author(s):  
Patrick Seeling ◽  
Martin Reisslein ◽  
Frank H. P. Fitzek
Keyword(s):  
Real Time ◽  
Data Streams ◽  
Control Loop ◽  
Real World Data ◽  
Perceptual Coding ◽  
Great Flexibility ◽  
Broad Application ◽  
Time Compression ◽  
Perceptual Threshold ◽  
Selection Of

The Tactile Internet will require ultra-low latencies for combining machines and humans in systems where humans are in the control loop. Real-time and perceptual coding in these systems commonly require content-specific approaches. We present a generic approach based on deliberately reduced number accuracy and evaluate the trade-off between savings achieved and errors introduced with real-world data for kinesthetic movement and tele-surgery. Our combination of bitplane-level accuracy adaptability with perceptual threshold-based limits allows for great flexibility in broad application scenarios. Combining the attainable savings with the relatively small introduced errors enables the optimal selection of a working point for the method in actual implementations.

scholarly journals Nanometre-Scale Visualization of Chemical Parameter Changes by T1-Weighted ODMR Imaging Using a Fluorescent Nanodiamond

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 68
Author(s):  
Takahiro Fujisaku ◽  
Ryuji Igarashi ◽  
Masahiro Shirakawa
Keyword(s):  
Magnetic Resonance ◽  
Laser Pulse ◽  
Real Time ◽  
Physical Parameters ◽  
Biological Processes ◽  
Chemical Parameter ◽  
Ph Conditions ◽  
Optically Detected ◽  
Life Phenomena ◽  
Selection Of

The dynamics of physical parameters in cells is strongly related to life phenomena; thus, a method to monitor and visualize them on a single-organelle scale would be useful to reveal unknown biological processes. We demonstrate real-time nanometre-scale T1-weighted imaging using a fluorescent nanodiamond. We explored optically detected magnetic resonance (ODMR) contrast at various values of interval laser pulse (τ), showing that sufficient contrast is obtained by appropriate selection of τ. By this method, we visualized nanometre-scale pH changes using a functionalized nanodiamond whose T1 has a dependence on pH conditions.

scholarly journals Development of a Colorimetric Sensor for Autonomous, Networked, Real-Time Application

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5857
Author(s):  
Brandy J. Johnson ◽  
Anthony P. Malanoski ◽  
Jeffrey S. Erickson
Keyword(s):  
Real Time ◽  
Field Trials ◽  
Wireless Sensor ◽  
Broad Area ◽  
Ongoing Effort ◽  
Environmental Air ◽  
Further Development ◽  
Real Time Application ◽  
Selection Of ◽  
Event Occurrence

This review describes an ongoing effort intended to develop wireless sensor networks for real-time monitoring of airborne targets across a broad area. The goal is to apply the spectrophotometric characteristics of porphyrins and metalloporphyrins in a colorimetric array for detection and discrimination of changes in the chemical composition of environmental air samples. The work includes hardware, software, and firmware design as well as development of algorithms for identification of event occurrence and discrimination of targets. Here, we describe the prototype devices and algorithms related to this effort as well as work directed at selection of indicator arrays for use with the system. Finally, we review the field trials completed with the prototype devices and discuss the outlook for further development.

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