1,721,003 research outputs found
EDCircles: A real-time circle detector with a false detection control
No full textWOS: 000313385700011We propose a real-time, parameter-free circle detection algorithm that has high detection rates, produces accurate results and controls the number of false circle detections. The algorithm makes use of the contiguous (connected) set of edge segments produced by our parameter-free edge segment detector, the Edge Drawing Parameter Free (EDPF) algorithm; hence the name EDCircles. The proposed algorithm first computes the edge segments in a given image using EDPF, which are then converted into line segments. The detected line segments are converted into circular arcs, which are joined together using two heuristic algorithms to detect candidate circles and near-circular ellipses. The candidates are finally validated by an a contrario validation step due to the Helmholtz principle, which eliminates false detections leaving only valid circles and near-circular ellipses. We show through experimentation that EDCircles works real-time (10-20 ms for 640 x 480 images), has high detection rates, produces accurate results, and is very suitable for the next generation real-time vision applications including automatic inspection of manufactured products, eye pupil detection, circular traffic sign detection, etcScientific and Technological Research Council of Turkey (TUBITAK) [111E053]We are deeply indebted to anonymous reviewers for their insightful comments, which greatly helped shape this paper for the better. We also thank the Scientific and Technological Research Council of Turkey (TUBITAK) for supporting this work with the Grant no. 111E053
Edpf: a Real-Time Parameter-Free Edge Segment Detector With a False Detection Control
No full textWOS: 000308103400004We propose a real-time, parameter-free edge/edge segment detection algorithm based on our novel edge/edge segment detector, the edge drawing (ED) algorithm; hence the name edge drawing parameter free (EDPF). EDPF works by running ED with ED's parameters set at their extremes. This produces all edge segments in a given image with numerous false detections. The detected edge segments are then validated by an "a contrario" validation step due to the Helmholtz principle, which eliminates invalid detections leaving only "meaningful" edge segments
Blind Rectification of Radial Distortion by Line Straightness
No full text24th European Signal Processing Conference (EUSIPCO) -- AUG 28-SEP 02, 2016 -- Budapest, HUNGARYWOS: 000391891900179Lens distortion self-calibration estimates the distortion model using arbitrary images captured by a camera. The estimated model is then used to rectify images taken with the same camera. These methods generally use the fact that built environments are line dominated and these lines correspond to lines on the image when distortion is not present. The proposed method starts by detecting groups of lines whose real world correspondences are likely to be collinear. These line groups are rectified, then a novel error function is calculated to estimate the amount of remaining distortion. These steps are repeated iteratively until suitable distortion parameters are found. A feature selection method is used to eliminate the line groups that are not collinear in the real world. The method is demonstrated to successfully rectify real images of cluttered scenes in a fully automatic manner.European Assoc Signal Pro
Edcircles: Real-Time Circle Detection By Edge Drawing (Ed)
No full textIEEE International Conference on Acoustics, Speech and Signal Processing -- MAR 25-30, 2012 -- Kyoto, JAPANWOS: 000312381401105We propose a real-time, parameter-free circle detection algorithm that produces accurate results with very few false positives. The algorithm makes use of the contiguous (connected) set of edge segments produced by our novel edge segment detector, the Edge Drawing (ED) algorithm; hence the name EDCircles. The proposed algorithm first fits line segments to ED's edge segments and then processes these line segments to detect circles in a given image. We show through experimentation that EDCircles works real-time, produces good results, and is very suitable for the next generation real-time automation applications including automatic inspection of manufactured products, human eye iris and pupil detection, circular traffic sign detection, etc.Inst Elect & Elect Engineers, Signal Processing Soc, IEE
Enabling peer-to-peer communication for hosts in private address realms using IPv4 LSRR option and IPv4+4 addresses
No full textWOS: 000265597700002Enabling 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.Turkish Science and Technology Research Institute (TUBITAK) [107E166]This work was partially supported by Turkish Science and Technology Research Institute (TUBITAK) grant 107E166
Edge Drawing: A combined real-time edge and segment detector
No full textWOS: 000307134900004We 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)The Scientific and Technological Research Council of Turkey (TUBITAK) [111E053]This work is partially supported by The Scientific and Technological Research Council of Turkey (TUBITAK) with Grant No. 111E053
Edlines: Real-Time Line Segment Detection By Edge Drawing (Ed)
No full text18th IEEE International Conference on Image Processing (ICIP) -- SEP 11-14, 2011 -- Brussels, BELGIUMWOS: 000298962502242We propose a linear time line segment detector that gives accurate results, requires no parameter tuning, and runs up to 11 times faster than the fastest known line segment detection algorithm in the literature; namely, the LSD by Gioi et al. The proposed algorithm also includes a line validation step due to the Helmholtz principle, which lets it control the number of false detections. Our detector makes use of the clean, contiguous (connected) chain of edge pixels produced by our novel edge detector, the Edge Drawing (ED) algorithm; hence the name EDLines. With its accurate results and blazing speed, EDLines will be very suitable for the next generation real-time computer vision applications.IEEE, IEEE Signal Proc Soc (SPS
Prediction error PDF improvement in multichannel predictive coders [Çok kanalli öngörüye dayali kodlayicilarda öngörü hata dagiliminin i·yileştirilmesi]
No full text2006 IEEE 14th Signal Processing and Communications Applications -- 17 April 2006 through 19 April 2006 -- Antalya -- 69461In this paper, multichannel predictive image coder outputs are investigated within each channel. By obtaining prediction error biases and compensating them in each channel, the total error histogram is sharpene
Pdf sharpening for multichannel predictive coders
No full textISL Altran;Galileo Avionics;Selex Sistemi Intergrati;STMicroelectronics;University of Pisa14th European Signal Processing Conference, EUSIPCO 2006 -- 4 September 2006 through 8 September 2006 -- Florence -- 90688Predictive coders that split the prediction decision into con-texts depending on the local image behaviour have proved to be practically useful and successful in image coding applications. Such predictive coders can be named as multi-channel. LOCO is a simple, yet successful example of such coders. Due to its success, a fair amount of attention has been paid for the improvement of multi-channel predictive coders. The common task for these coders is to split the pixel layout around the pixel of interest into a list of contexts or prediction rules that specifically succeeds in predicting the value in a reasonable way. The improvement proposed in this work is due to the well known observation that the pre-diction error pdfs are not identically or evenly distributed for each channel output. Although several methods have been proposed for the compensation of this situation, they mostly perturb the low complexity behaviour. In this work, it is shown that a two-pass coder is a simple, yet efficient improvement that perfectly determines channel pdf bias amounts, and the adjustment produces up to 5% compression improvement over the test images
Prediction error PDF improvement in multichannel predictive coders
No full textIEEE 14th Signal Processing and Communications Applications -- APR 16-19, 2006 -- Antalya, TURKEYWOS: 000245347800016In this paper, multichannel predictive image coder outputs are investigated within each channel. By obtaining prediction error biases and compensating them in each channel, the total error histogram is sharpened.IEE
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