IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 16, NO. 5, OCTOBER 2015 2599
Vision-Based Nighttime Vehicle Detection
Using CenSurE and SVM
Naoya Kosaka and Gosuke Ohashi, Member, IEEE
Abstract—In this paper, we propose a method for detecting
vehicles from a nighttime driving scene taken by an in-vehicle
monocular camera. Since it is difficult to recognize the shape of
the vehicles during nighttime, vehicle detection is based on the
headlights and the taillights, which are bright areas of pixels
called blobs. Many research studies using automatic multilevel
thresholding are being conducted, but these methods are prone to
get affected by the ambient light because it uses the luminance of
the whole image to derive the thresholds. Owing to such reasons,
we focused on the Laplacian of Gaussian operator, which derives
the response of luminance difference between the blob and its
surroundings. Compared with automatic multilevel thresholding,
Laplacian of Gaussian operator is more robust to the ambient
light. However, the computational cost to derive the response
of this operator is large. Therefore, we used a method called
Center Surround Extremas to detect the blobs in high speed. Since
the detected blobs include nuisance lights, we had to determine
whether the blob is a light of a vehicle or not. Thus, we classified
them according to the features of the blob using support vector
machines. Then, we detected vehicle traffic lane and specified
the region where the vehicle may exist. Finally, we classified the
blobs based on the movements across the frames. We applied the
proposed method to nighttime driving sequences and confirmed
the effectiveness of the classification process used in this method
and that it could process within frame rate.
Index Terms—Intelligent transport systems, nighttime driving
scenes, vehicle detection, Center Surround Extremas.
I. INTRODUCTION
R
ECENTLY, many researches on Intelligent Transport
Systems (ITS) are being conducted. As part of ITS, the
approaches based on vehicle detection from images taken by
a camera mounted on a vehicle have been conducted [1], [2].
Researches using a vehicle-mounted camera for various on-
road applications are attracting attention, because the cost of
the camera is lower than other sensors, such as radar, and it can
identify the shape, color, and size of an object in high speed ow-
ing to th e develo pment of arithmetic capacity of the c omputer.
Based on computer vision, a system that measures the distance
to the object to warn drivers o f the dangers of possible collision
and a system th at prevents the vehicle fro m deviating from the
lane are being developed. From such a background, the aim of
this stud y is to detect vehicles from images at nighttime for the
Manuscript recei ved September 22, 2014; revised December 26, 2014 and
March 9, 2015; accepted March 12, 2015. Date of publication May 7, 2015;
date of current version September 25, 2015. The Associate Editor for this paper
was B. Morris.
The authors are with the Department of Electrical and Electronic Engineer-
ing, Shizuoka University, Hamamatsu 432-8561, Japan (e-mail: tegooha@ipc.
shizuoka.ac.jp).
Color versions of one or more of the figures in this paper are available online
at http://ieeexplore.ieee.org.
Digital Object Identifier 10.1109/TITS.2015.2413971
application of automatic headlight controller, which switches
between low and high beams depending on the existence of
other vehicles. At nighttime, if there are no oncoming and
leading vehicles existing in front of one’s vehicle, headlights
are preferred to be controlled to high beam to ensure visibility.
On the other hand, if oncoming or leading vehicle appears in
front, in order not to dazzle the driver, the headlight must be
dipped to low beam. Automating this operation would reduce
the driver’s operation error, leading to safe driving.
In daytime, vehicle detection is based on the shape of the
vehicles [3]–[8]. However, because of its low visibility at night-
time, it is difficult to recognize shape; hence, detection at night-
time is based on the headlights and taillights of the vehicles,
which have high luminance [9]–[17]. In previous studies, to
segment the blobs, they proposed methods of binarization using
a simple threshold [9] or an automatic multilevel thresholding
using multilevel thresholds to the images [10]–[18]. In these
methods, however, under various ambient light conditions, it
may be difficult to correctly segment the blob. In addition,
a scene that contains vehicles close to and far from one’s
vehicle may become difficult to detect because the luminance
corresponds to the distance from the camera. Moreover, since
the headlights of onco ming vehicle an d the taillights of lead-
ing vehicle have different luminances, the detection becomes
more difficult. In these researches, after detecting blobs using
multilevel thresholding, the blobs are classified based on their
size and shape, but as the threshold changes in frames, the
feature of size and shape would be different and would affect
the classification. The examples of segmented im age using
Otsu thresholding, which automatically selects the appropriate
threshold for segmenting the image into two classes, are shown
in Fig. 1. The two class-segmented results of the original
images shown in Fig. 1(a) and (c) are shown in Fig. 1(b) and (d),
respectively. There are scenes that could extract lights as shown
in Fig. 1(b), but scenes in which ambient light conditions
change like in Fig. 1(c), it is difficult to extract the lights of
the vehicle.
We focused on the response of Laplacian of Gaussian (LoG)
operator, to extract the bright region when compared with
the surroundings (contrast) without simply extracting the high
luminance area. The LoG operator detects objects brighter than
the surrounding area; hence, it is more robust than multilevel
thresholding, which uses the luminance of the whole image to
determine the threshold. To correspond to the various sizes of
the light of the vehicle, it is necessary to derive response from
multiple scales of LoG operator, but the calculation time is large
for practical use. Therefore, we use Center Surround Extremas
(CenSurE) [19], which uses an integral image for deriving
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