D.M. Gavrila
V. Philomin
Image Understanding Systems
DaimlerChrysler Research
Ulm 89081, Germany dariu.gavrila@DaimlerChrysler.com Computer Vision Laboratory
University of Maryland
College Park, MD 20742, U.S.A. vasi@cs.umd.edu ABSTRACT
This paper presents an e cient shape-based object detection method based on Distance Transforms and describes its use for real-time vision on-board vehicles.
The method uses a template hierarchy to capture the variety of object shapes; e cient hierarchies can be generated o ine for given shape distributions using stochastic optimization techniques i.e. simulated annealing. Online, matching involves a simultaneous coarse-to- ne approach over the shape hierarchy and over the transformation parameters. Very large speedup factors are typically obtained when comparing this approach with the equivalent brute-force formulation; we have measured gains of several orders of magnitudes.
We present experimental results on the real-time detection of tra c signs and pedestrians from a moving vehicle. Because of the highly time sensitive nature of these vision tasks, we also discuss some hardwarespeci c implementations of the proposed method as far as SIMD parallelism is concerned.
if he makes a wrong turn in a one-way street or if he is speeding. Alternatively, a system to detect pedestrians might reduce the accident rate by taking either passive or active measures to deal with upcoming collisions.
In this paper, we present a shape-based method which can be used for that purpose; it is general enough to detect objects of arbitrary shapes. Models or other parametrizations need not to be established explicitly, which is an advantage when dealing with non-rigid objects such as pedestrians. Instead, the method is able to generate an e cient representation from example shapes o -line; matching proceeds on-line using a novel variant of Distance Transform DT - based matching.
The outline of the
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