| 11. |
- Imran, Muhammad, et al.
(författare)
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Low complexity FPGA based background subtraction technique for thermal imagery
- 2015
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Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450336819 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Embedded smart camera systems are gaining popularity for a number of real world surveillance applications. However, there are still challenges, i.e. variation in illumination, shadows, occlusion, and weather conditions while employing the vision algorithms in outdoor environments. For safety-critical surveillance applications, the visual sensors can be complemented with beyond-visual-range sensors. This in turn requires analysis, development and modification of existing imaging techniques. In this work, a low complexity background modelling and subtraction technique has been proposed for thermal imagery. The proposed technique has been implemented on Field Programmable Gate Arrays (FPGAs) after in-depth analysis of different sets of images, characterizing poor signal-to-noise ratio challenges, e.g. motion of high frequency background objects, temperature variation and camera jitter etc. The proposed technique dynamically updates the background on pixel level and requires a single frame storage as opposed to existing techniques. The comparison of this approach with two other approaches show that this approach performs better in different environmental conditions. The proposed technique has been modelled in Register Transfer Logic (RTL) and implementation on the latest FPGAs shows that the design requires less than 1 percent logics, 47 percent block RAMs, and consumes 91 mW power consumption on Artix-7 100T FPGA.
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| 12. |
- Imran, Muhammad, et al.
(författare)
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Pre-processing Architecture for IR-Visual Smart Camera Based on Post-Processing Constraints
- 2016
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Konferensbidrag (refereegranskat)abstract
- In embedded vision systems, the efficiency of pre-processing architectures have a ripple effect on post-processing functions such as feature extraction, classification and recognition. In this work, we investigated a pre-processing architecture for smart camera system, integrating a thermal and vision sensors, by considering the constraints of post-processing. By utilizing the locality feature of the system, we performed pre-processing on the camera node by using FPGA and post-processing on the client device by using the microprocessor platform, NVIDIA Tegra. The study shows that for outdoor people surveillance applications with complex background and varying lighting conditions, the pre-processing architecture, which transmits thermal binary Region-of-Interest (ROI) images, offers better classification accuracy and smaller complexity as compared to alternative approaches.
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| 13. |
- Imran, Muhammad, et al.
(författare)
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STC-CAM1, IR-visual based smart camera system
- 2015
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Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450336819 ; , s. 195-196
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Konferensbidrag (refereegranskat)abstract
- Safety-critical applications require robust and real-time surveillance. For such applications, a vision sensor alone can give false positive results because of poor lighting conditions, occlusion, or different weather conditions. In this work, a visual sensor is complemented by an infrared thermal sensor which makes the system more resilient in unfavorable situations. In the proposed camera architecture, initial data intensive tasks are performed locally on the sensor node and then compressed data is transmitted to a client device where remaining vision tasks are performed. The proposed camera architecture is demonstrated as a proof-ofconcept and it offers a generic architecture with better surveillance while only performing low complexity computations on the resource constrained devices.
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| 14. |
- Krug, Silvia, et al.
(författare)
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A Case Study on Energy Overhead of Different IoT Network Stacks
- 2019
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Ingår i: 2019 IEEE 5th World Forum on Internet of Things (WF-IoT). - : IEEE. - 9781538649817 - 9781538649800 ; , s. 528-529
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Konferensbidrag (refereegranskat)abstract
- Due to the limited energy budget for sensor nodes in the Internet of Things (IoT), it is crucial to develop energy efficient communications amongst others. This need leads to the development of various energy-efficient protocols that consider different aspects of the energy status of a node. However, a single protocol covers only one part of the whole stack and savings on one level might not be as efficient for the overall system, if other levels are considered as well. In this paper, we analyze the energy required for an end device to maintain connectivity to the network as well as perform application specific tasks. By integrating the complete stack perspective, we build a more holistic view on the energy consumption and overhead for a wireless sensor node. For better understanding, we compare three different stack variants in a base scenario and add an extended study to evaluate the impact of retransmissions as a robustness mechanism. Our results show, that the overhead introduced by the complete stack has an significant impact on the nodes energy consumption especially if retransmissions are required.
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| 15. |
- Krug, Silvia, et al.
(författare)
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IoT Communication Introduced Limitations for High Sampling Rate Applications
- 2018
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Ingår i: GI/ITG KuVS Fachgespräch Sensornetze 13. & 14. September 2018, Braunschweig : Technical Report.
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Konferensbidrag (refereegranskat)abstract
- Networking solutions for the Internet of Things aretypically designed for applications that require low data rates andfeature rare transmission events. The initial assumption leads to asystem design towards minimal data transfers and packet sizes.However, this can become a challenge, if applications requiredifferent traffic patterns or cooperative interaction betweendevices. Applications requiring a high sampling rate to capturethe desired phenomenon produce larger amounts of data thatneed to be transported. In this paper, we present a studyhighlighting some of the challenging aspects for such applicationsand how the choice of communication technology can limit bothapplication behavior and network structure.
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| 16. |
- Krug, Silvia, et al.
(författare)
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Modeling and Comparison of Delay and Energy Cost of IoT Data Transfers
- 2019
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Ingår i: IEEE Access. - 2169-3536. ; 7, s. 58654-58675
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Tidskriftsartikel (refereegranskat)abstract
- Communication is often considered as the most costly component of a wireless sensor node. As a result, a variety of technologies and protocols aim to reduce the energy consumption for the communication especially in the Internet of Things context. In order to select the best suitable technology for a given use case, a tool that allows the comparison of these options is needed. The goal of this paper is to introduce a new modular modeling framework that enables a comparison of various technologies based on analytical calculations. We chose to model the cost for a single data transfer of arbitrary application data amounts in order to provide flexibility regarding the data amount and traffic patterns. The modeling approach covers the stack traversal of application data and thus in comparison to other approaches includes the required protocol overhead directly. By applying our models to different data amounts, we are able to show tradeoffs between various technologies and enable comparisons for different scenarios. In addition, our results reveal the impact of design decisions that can help to identify future development challenges.
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| 17. |
- Krug, Silvia, et al.
(författare)
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Suitability of Communication Technologies for Harvester-Powered IoT-Nodes
- 2019
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Ingår i: IEEE International Workshop on Factory Communication Systems - Proceedings, WFCS. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728112688
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Konferensbidrag (refereegranskat)abstract
- The Internet of Things introduces Internet connectivity to things and objects in the physical world and thus enables them to communicate with other nodes via the Internet directly. This enables new applications that for example allow seamless process monitoring and control in industrial environments. One core requirement is that the nodes involved in the network have a long system lifetime, despite limited access to the power grid and potentially difficult propagation conditions. Energy harvesting can provide the required energy for this long lifetime if the node is able to send the data based on the available energy budget. In this paper, we therefore analyze and evaluate which common IoT communication technologies are suitable for nodes powered by energy harvesters. The comparison includes three different constraints from different energy sources and harvesting technologies besides several communication technologies. Besides identifying possible technologies in general, we evaluate the impact of duty-cycling and different data sizes. The results in this paper give a road map for combining energy harvesting technology with IoT communication technology to design industrial sensor nodes.
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| 18. |
- Lawal, Najeem, et al.
(författare)
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Design exploration of a multi-camera dome for sky monitoring
- 2016
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Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450347860 ; , s. 14-18
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Konferensbidrag (refereegranskat)abstract
- Sky monitoring has many applications but also many challenges to be addressed before it can be realized. Some of the challenges are cost, energy consumption and complex deployment. One way to address these challenges is to compose a camera dome by grouping cameras that monitor a half sphere of the sky. In this paper, we present a model for design exploration that investigates how characteristics of camera chips and objective lenses affect the overall cost of a node of a camera dome. The investigation showed that by accepting more cameras in a single node can result in a reduced total cost of the system. This concludes that by using suitable design and camera placement technique, a cost-effective solution can be proposed for massive open-area i.e. sky monitoring.
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| 19. |
- Nie, Yali, et al.
(författare)
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Automatic Detection of Melanoma with Yolo Deep Convolutional Neural Networks
- 2019
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Ingår i: 2019 E-Health and Bioengineering Conference (EHB). - : IEEE. - 9781728126036
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Konferensbidrag (refereegranskat)abstract
- In the past three years, deep convolutional neural networks (DCNNs) have achieved promising performance in detecting skin cancer. However, improving the accuracy and efficiency of the automatic detection of melanoma is still urgent due to the visual similarity of benign and malignant dermoscopy. There is also a need for fast and computationally effective systems for mobile applications targeting caregivers and homes. This paper presents the You Only Look Once (Yolo) algorithms, which are based on DCNNs applied to the detection of melanoma. The Yolo algorithms comprise YoloV1, YoloV2, and YoloV3, whose methodology first resets the input image size and then divides the image into several cells. According to the position of the detected object in the cell, the network will try to predict the bounding box of the object and the class confidence score. Our test results indicate that the mean average precision (mAP) of Yolo can exceed 0.82 with a training set of only 200 images, proving that this method has great advantages for detecting melanoma in lightweight system applications.
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| 20. |
- Rydblom, Staffan, 1975-
(författare)
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Measuring Water Droplets to Detect Atmospheric Icing
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes the exploration of a method to measurethe droplet size and the concentration of atmospheric liquid water. The purpose is to find a cost effective technique to detect the conditions for icing on structures.Icing caused by freezing atmospheric water can be a signifi- cant problem for infrastructure such as power lines, roads and air traffic. About one third of the global installed wind power capacity is located in cold climates, where icing of rotor blades is one of the major challenges.The icing process is complex and the result depends on a combination of the aerodynamic shape of the structure or airfoil, the velocity of the air and its contained water, the temperature, the mixing of snow and water, the concentration of liquid water and the Droplet Size Distribution (DSD).The measurement method is based on a shadowgraph imag- ing system using light emitting diode (LED) light as background illumination and digital image processing. A prototype instru- ment has been constructed. The components were selected keeping the possibility of low-cost volume production in mind. The applications of a commercial instrument based on this tech- nique are e.g. real-time in-situ icing condition measurements and assimilation and verification of data in numerical weather models.The work presented shows that measurements of the size and concentration of water droplets using shadowgraph images can be used for the comparison and validation of Numerical Weather Prediction (NWP) models and other instruments. The accuracy of the particle size measurement is high. The accuracy of the concentration measurement has the potential to become high due to the single-particle measurement range calibraiton. The precision of the instrument depends mainly on the number of images that is used to find each measurement value. The real-time performance of the instrument is limited by the image retrieval and processing speed and depends on the precisionrequired.
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