Evaluating Signature Matching in a Multi-Sensor Vehicle Classification System (extended)

Chengjie Zhang and John Heidemann
USC/Information Sciences Institute

Abstract

Many academic sensornet systems consider the problem of tracking targets as they move through a fixed field of sensors. Such applications must relate sensor detections to specific targets, yet prior work has often ignored this problem, assuming either a single target, sufficient spatial separation that target-to-sensor mapping is clear, or some out-of-band detection-to-target mapping. There has been little study of algorithms to associate detections with targets, and effects of their accuracy on detection results, particularly in environments with dense targets. We explore the question of detection-to-target mapping in the context of a vehicle classification system for urban roadways, where vehicles pass fixed sensors at varying but frequent rates. We develop several signature matching algorithms that relate detections at different sensors to same or different vehicles. We evaluate these algorithms with data taken in a field test of live traffic compared against ground truth obtained through manual analysis of video and the resulting matching recall is over 78%. We investigate the effects of mapping accuracy on length-based vehicle classification. We show that accurate signature matching is critical to multi-sensor algorithms. We compare our matching algorithms against an oracle (perfect information), and find that all matching reduces end-to-end accuracy somewhat, but a poor matching algorithm reduce accuracy by 21%, while our best algorithm reduces it by only 10% in our case study. Finally, we quantify the degree of correlation between matching correctness and classification accuracy.

Availability

This paper is available in several formats: abstract web page with pointers and cites, PDF, paper copies can be obtained by mail to the authors. Copyright terms for this paper appear below.

Reference

Zhang11c

Chengjie Zhang and John Heidemann. Evaluating Signature Matching in a Multi-Sensor Vehicle Classification System (extended) . Technical Report ISI-TR-2011-675, USC/Information Sciences Institute, November, 2011. <http://www.isi.edu/~johnh/PAPERS/Zhang11c.html>.

@techreport{Zhang11c,
	author = "Chengjie Zhang and John Heidemann",
	title = "Evaluating Signature Matching in a Multi-Sensor Vehicle Classification System (extended) ",
	institution = "USC/Information Sciences Institute",
	year = "2011",
	number = "ISI-TR-2011-675",
	month = "November",
	keywords = "signature matching, multi-sensor",
	url = "http://www.isi.edu/~johnh/PAPERS/Zhang11c.html",
	pdfurl = "http://www.isi.edu/~johnh/PAPERS/Zhang11c.pdf",
	myorganization = "USC/Information Sciences Institute",
	copyrightholder = "authors",
}

Copyright

This paper is copyright © 2011 by its authors. Permission to make digital or hard copies of part or all of this work for personal use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that new copies bear this notice and the full citation on the first page. Abstracting with credit is permitted.

To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission of the authors.