Edge Drawing: A combined real-time edge and segment detector

We present a novel edge segment detection algorithm that runs real-time and produces high quality edge segments, each of which is a linear pixel chain. Unlike traditional edge detectors, which work on the thresholded gradient magnitude cluster to determine edge elements, our method first spots sparse points along rows and columns called anchors, and then joins these anchors via a smart, heuristic edge tracing procedure, hence the name Edge Drawing (ED). ED produces edge maps that always consist of clean, perfectly contiguous, well-localized, one-pixel wide edges. Edge quality metrics are inherently satisfied without a further edge linking procedure. In addition, ED is also capable of outputting the result in vector form as an array of chain-wise edge segments. Experiments on a variety of images show that ED produces high quality edge maps and runs up to 10% faster than the fastest known implementation of the Canny edge detector (OpenCV’s implementation).     

EDTriangles: a high-speed triangle detection algorithm with a false detection control

We present a high-speed method for triangular object detection. The proposed method utilizes the recently developed, real-time edge segment detection algorithm, Edge Drawing; hence, the name EDTriangles, which consists of a detection stage and a validation stage. In the detection stage, EDTriangles extracts edge segments from the image using Edge Drawing and converts these edge segments into line segments, which are then converted into line pairs according to the angles between the line segments and the distance between their endpoints. Next, the line pairs are combined together using some heuristics to generate many triangle candidates, some of which are valid detections and some invalid. Finally, in the validation stage the candidate triangles are validated using the Helmholtz principle and number of false alarms computation to eliminate false detections. Experimental results show that EDTriangles runs very fast, detects various types of triangular objects ranging from narrow to wide-angled triangles and offers a higher detection performance compared to some of the well-known triangle detection algorithms found in the literature.     

QoS guarantee for multimedia traffic in smart homes

With the advent of home networking and widespread deployment of broadband connectivity to homes, a wealth of new services with real-time Quality of Service (QoS) requirements have emerged, e.g., Video on Demand (VoD), IP Telephony, which have to co-exist with traditional non-real-time services such as Web browsing and file downloading over the Transmission Control Protocol (TCP). The co-existence of such real-time and non-real-time services demands the residential gateway (RG) to employ bandwidth management algorithms to control the amount of non-real-time TCP traffic on the broadband access link from the Internet Service Provider (ISP) to the RG so that the bandwidth requirements of the real-time traffic are satisfied. In this paper we propose an algorithm to control the aggregate bandwidth of the incoming non-real-time TCP traffic at the RG so that QoS requirements of the real-time traffic can be guaranteed. The idea is to limit the maximum data rates of active TCP connections by dynamically manipulating their flow control window sizes based on the total available bandwidth for the non-real-time traffic. We show by simulation results that our algorithm limits the aggregate bandwidth of the non-real-time TCP traffic thus granting the real-time traffic the required bandwidth.     

A scalable bandwidth guaranteed distributed continuous media file system using network attached autonomous disks

Repository for continuous media data differs from that of the traditional text-based data both in storage space and streaming bandwidth requirements. The file systems used for continuous media streams need to support large volumes and high bandwidth. We propose a scalable distributed continuous media file system built using autonomous disks. Autonomous disks are attached directly to the network and are able to perform lightweight processing. We discuss different ways to realize the autonomous disk, and describe a prototype implementation on a Linux platform using PC-based hardware. We present the basic requirements of the continuous media file system and present the design methodology and a prototype Linux-based implementation of the distributed file system that supports the requirements. We present experimental results on the performance of the proposed file system prototyped using autonomous disks. We show that the performance of the file system scales linearly with the number of disks and the number of clients. The file system performs much superior to NFS running on the same hardware platform and can deliver higher raw disk bandwidth to the applications. We also present bandwidth and time sensitive read/write procedures for the file system and show that the file system can provide strict bandwidth guarantees for continuous media streams.     

Enabling peer-to-peer communication for hosts in private address realms using IPv4 LSRR option and IPv4+4 addresses

Enabling peer-to-peer (P2P) communication for hosts behind network address translation (NAT) boxes is an important and difficult problem. Existing proposals, for example, UPnP, MIDCOM, TURN, STUN, STUNT, P2PNAT, NATBlaster among others, offer only partial, limited and non-deterministic solutions. A framework that offers a complete solution to the P2P communication problem is presented. The proposed framework is based on the use of IPv4+4 addresses and the standard IPv4 Loose Source Record Route (LSRR) option and requires no changes whatsoever to end-host protocol stacks and Internet routers. The only requirement is a simple upgrade of border routers with a new LSRR-based packet-forwarding algorithm for the P2P traffic. The implementation of a Linux-based border router that runs the proposed forwarding algorithm is detailed, and how P2P applications can benefit from this framework is described.