| 61. |
- Imran, Muhammad
(författare)
-
Investigation of Architectures for Wireless Visual Sensor Nodes
- 2011
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wireless visual sensor network is an emerging field which has proveduseful in many applications, including industrial control and monitoring,surveillance, environmental monitoring, personal care and the virtual world.Traditional imaging systems used a wired link, centralized network, highprocessing capabilities, unlimited storage and power source. In manyapplications, the wired solution results in high installation and maintenancecosts. However, a wireless solution is the preferred choice as it offers lessmaintenance, infrastructure costs and greater scalability.The technological developments in image sensors, wirelesscommunication and processing platforms have paved the way for smartcamera networks usually referred to as Wireless Visual Sensor Networks(WVSNs). WVSNs consist of a number of Visual Sensor Nodes (VSNs)deployed over a large geographical area. The smart cameras can performcomplex vision tasks using limited resources such as batteries or alternativeenergy sources, embedded platforms, a wireless link and a small memory.Current research in WVSNs is focused on reducing the energyconsumption of the node so as to maximise the life of the VSN. To meet thischallenge, different software and hardware solutions are presented in theliterature for the implementation of VSNs.The focus in this thesis is on the exploration of energy efficientreconfigurable architectures for VSNs by partitioning vision tasks on software,hardware platforms and locality. For any application, some of the vision taskscan be performed on the sensor node after which data is sent over the wirelesslink to the server where the remaining vision tasks are performed. Similarly,at the VSN, vision tasks can be partitioned on software and the hardwareplatforms.In the thesis, all possible strategies are explored, by partitioning visiontasks on the sensor node and on the server. The energy consumption of thesensor node is evaluated for different strategies on software platform. It isobserved that performing some of the vision tasks on the sensor node andsending compressed images to the server where the remaining vision tasks areperformed, will have lower energy consumption.In order to achieve better performance and low power consumption,Field Programmable Gate Arrays (FPGAs) are introduced for theimplementation of the sensor node. The strategies with reasonable designtimes and costs are implemented on hardware-software platform. Based onthe implementation of the VSN on the FPGA together with micro-controller,the lifetime of the VSN is predicted using the measured energy values of theplatforms for different processing strategies. The implementation resultsprove our analysis that a VSN with such characteristics will result in a longerlife time.
|
|
| 62. |
- Imran, Muhammad, et al.
(författare)
-
Low Complexity Background Subtraction for Wireless Vision Sensor Node
- 2013
-
Ingår i: Proceedings - 16th Euromicro Conference on Digital System Design, DSD 2013. - 9780769550749 ; , s. 681-688
-
Konferensbidrag (refereegranskat)abstract
- Wireless vision sensor nodes consist of limited resources such as energy, memory, wireless bandwidth and processing. Thus it becomes necessary to investigate lightweight vision tasks. To highlight the foreground objects, many machine vision applications depend on the background subtraction technique. Traditional background subtraction approaches employ recursive and non-recursive techniques and store the whole image in memory. This raises issues like complexity on hardware platform, energy requirements and latency. This work presents a low complexity background subtraction technique for a hardware implemented VSN. The proposed technique utilizes existing image scaling techniques for scaling down the image. The downscaled image is stored in memory of microcontroller which is already there for transmission. For subtraction operation, the background pixels are generated in real time through up scaling. The performance, and memory requirements of the system is compared for four image scaling techniques including nearest neighbor, averaging, bilinear, and bicubic. The results show that a system with lightweight scaling techniques, i.e., nearest neighbor and averaging, up to a scaling factor of 8, missed on average less than one object as compared to a system which uses a full original background image. The proposed approach will reduce the cost, design/implementation complexity and the memory requirement by a factor of up to 64.
|
|
| 63. |
- Imran, Muhammad, et al.
(författare)
-
Low complexity FPGA based background subtraction technique for thermal imagery
- 2015
-
Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450336819 ; , s. 1-6
-
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.
|
|
| 64. |
- Imran, Muhammad, et al.
(författare)
-
Pre-processing Architecture for IR-Visual Smart Camera Based on Post-Processing Constraints
- 2016
-
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.
|
|
| 65. |
- Imran, Muhammad, et al.
(författare)
-
STC-CAM1, IR-visual based smart camera system
- 2015
-
Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450336819 ; , s. 195-196
-
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.
|
|
| 66. |
|
|
| 67. |
- Jantsch, A, et al.
(författare)
-
Comparison of Six Languages for System Level Descriptions of Telecom Systems
- 2001
-
Ingår i: Electronic Chips & Systems Design Languages. - Boston, Mass. : Kluwer Academic Publishers. - 0792373111 ; , s. 320-
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Language evaluation for various purposes is an often repeated exercise in industry and academia. Due to the large number of influencing factors the dependence of the result on implicit or explicit assumptions is not always apparent and clear. Based on a systematic evaluation method with a large number of criteria we compare six languages with respect to the suitability as a system specification and description language for telecom applications. The languages under evaluation are VHDL, C++, SDL, Haskell, Erlang, and ProGram, which represent different paradigms. The evaluation method allows to give specific emphasis on particular aspects in a controlled way, which we use to make separate comparisons for pure software systems, pure hardware systems and mixed HW/SW systems.
|
|
| 68. |
- Jantsch, A, et al.
(författare)
-
Conparison of six languages for system level descriptions of telecom systems
- 1998
-
Ingår i: Proceedings / FDL'98 / First International Forum on Design Languages. - Lausanne : Swiss Federal Inst. Of techn.. ; , s. 160-
-
Konferensbidrag (refereegranskat)abstract
- Language evaluation for various purposes is an often repeated exercise in industry and academia. Due to the large number of influencing factors the dependence of the result on implicit or explicit assumptions is not always apparent and clear. Based on a systematic evaluation method with a large number of criteria we compare six languages with respect to the suitability as a system specification and description language for telecom applications. The languages under evaluation are VHDL, C++, SDL, Haskell, Erlang, and ProGram, which represent different paradigms. The evaluation method allows to give specific emphasis on particular aspects in a controlled way, which we use to make separate comparisons for pure software systems, pure hardware systems and mixed HW/SW systems.
|
|
| 69. |
|
|
| 70. |
- Khursheed, Khursheed, et al.
(författare)
-
Bi-Level Video Codec for Machine Vision Embedded Applications
- 2013
-
Ingår i: Elektronika Ir Elektrotechnika. - : Kaunas University of Technology (KTU). - 1392-1215. ; 19:8, s. 93-96
-
Tidskriftsartikel (refereegranskat)abstract
- Wireless Visual Sensor Networks (WVSN) are feasible today due to the advancement in many fields of electronics such as Complementary Metal Oxide Semiconductor (CMOS) cameras, low power electronics, distributed computing and radio transceivers. The energy budget in WVSN is limited due to the small form factor of the Visual Sensor Nodes (VSNs) and the wireless nature of the application. The images captured by VSN contain huge amount of data which leads to high communication energy consumptions. Hence there is a need for designing efficient algorithms which are computationally less complex and provide high compression ratio. The change coding and Region of Interest (ROIs) coding are the options for data reduction of the VSN. But, for higher number of objects in the images, the compression efficiency of both the change coding and ROI coding becomes worse than that of image coding. This paper explores the compression efficiency of the Bi-Level Video Codec (BVC) for several representative machine vision applications. We proposed to implement image coding, change coding and ROI coding at the VSN and to select the smallest bit stream among the three. Results show that the compression performance of the BVC for such applications is always better than that of change coding and ROI coding.
|
|
