Classi icat ion of Ground Vehicles Using Acoustic
Signal Processing and Neural Network Classi ier
Manisha Kandpa1
1
,
Varun Kumar Kakar
2
, Gaurav Verma
3
1 Asst Professor, Deptt o fElectronics & Communication Engineering,
Jaipur National Universiy, Jaipur, Rajasthan, India
2
Asst Professor, Deptt ofElectronics & Communication Engineering,
B. T Kumaon Institute of Technoloy, Dwarahat, Uttarakhand, India
Asst Professor, Deptt ofElectronics & Communication Engineering,
Jypee universiy ofInformation and Technoloy, Noida-62, Uttar Pradesh, India
Abstract: Almost all moving vehicles generate some kind of noise
that can be due to the vibrations of engine, rotational parts,
bumping and friction of the vehicle tires with the ground, wind
effects, gears, fans etc. this sound provides an important clue or
characteristic pattern to recognize the vehicle type. Similar
vehicles working in comparable conditions would have a similar
acoustic signature that could be used for recognition.
Characteristic patterns may be extracted either in time domain
or frequency domain or a combination of these two i.e. time
frequency domain. Classi ication of ground vehicles based on
acoustic signals can be employed effectively in battleield
surveillance, traic control, military and many other
applications. In this paper we present eicient and less complex
method for feature extraction in time domain with the help of
Fourier transform. The recorded signals and their feature
vectors have to be stored and assigned to pre-existing categories
or classes i.e. these feature vectors will give us our database in
matrix form, which is used for vehicle classi icat ion in neural
network classi ier.
Keywords: Feature Extraction, Acoustic Signature, Energy Index,
Fourier Transform, Classi ication, Neural network classi ier.
I. INTRODUCTION
On road traic density has been increasing constantly
in recent years. Smart traic management systems are needed
to avoid traic congestions and accidents to ensure the safety
of road users. Although Traic surveillance systems based on
video cameras cover a broad range of different tasks, such as
vehicle count, lane occupancy, speed measurements and
classi ication, but if we use integration of data rom video,
audio, inrared, ultrasonic or inductive loop sensors then it
helps us to improve recognition rates and robustness as well as
reduces ambiguity and uncertainty of systems which depends
only on video images. So multi sensor nodes with integrated
data usion can be represented as a key for reliable and
conident trafic management systems in uture. Distinction
between different vehicle types such as cars, motorbikes,
busses or trucks provides useful information about road
utilization and traic statistics that is very useful for trafic
management systems. In this paper, we are presenting a
technique for vehicle identiication and classi ication by using
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its sound characteristics. Acoustic vehicle classiication is an
example of the pattern recognition theory. Almost all moving
vehicles produce typical characteristic sounds that are mainly
inluenced by their engine vibrations and riction between the
tires and road. From these characteristic sounds, some
attributes are extracted, called as features while a set of
features is called as feature vector, also sometimes referred as
acoustic signature. In classi ication problems this feature
vector is used to label that vehicle to one of the predeined
classes. The ability to recognize unknown pattens (vehicles)
is the e ic iency of classi ication.
An acoustic vehicle classi ication system mainly
consists of four stages [1]: Sensing, Segmentation, Feature
extraction and Classiication. The sensing part handles all
practical issues for physical sensors such as the microphone
setup, positioning, etc. S. Erb deines the scope of the sens ing
unit in a trafic management system as to collect raw data
rom a transducer in order to provide the sensor node with
information about traic condition [1]. Intrusive sensors like
inductive loop detectors, magnetometers or magnetic sensors
are oten used by transportation agencies [2]. They are put
under the pavement and work as vehicle detection devices. By
installing such sensors, speed and vehicle length may be
estimated and, based upon this information, lane occupancy,
gap and even the type of vehicle may be classi ied with
acceptable accuracy [3]. Due to the enclosed sensor form,
trafic has to be stopped and the road must be ton up every
time sensors are installed or maintained. The segmentation
algorithm is used to locate relevant information of individual
vehicles within the input data stream provided by the sensors .
In general aiplanes, helicopters, wind, steps, speech and other
vehicles create interfering sounds that have different acoustic
features in comparison to vehicles. Segmentation algorithm is
used to separate sound data of individual vehicle rom the
recorded sound. We may be able to extract a favorable time
interval for each vehicle, by using microphones on both sides
of the road for two way driving directions but there are still
some restrictions. When the gap between adjacent vehicles is
short, the valid time interval for the extraction of vehicle
sounds also becomes very small, which of course complicates
the calculation of reliable sound. Although microphone