Vol. XXXVIII, Part 7B
In: Wagner W., Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B
21
n. It is an information
s through the mobile
o make use of the
ce (Shu Wang 2008).
there are nine types of
Physical surroundings,
'Stem properties, Time
Iture and Orientation
t of the defined context
targets many users and
unication environment,
ivided for both pull and
ot rely on previous user
rridor be threatened by
ation messages will be
e 7, technical based
<rs (those could be any
the corridor situation,
application purpose),
technology, and data
nd service
ing information and send
isly, the provision of the
proach would involve a
tn, since the positions of
uously transmitted to the
to be send to the devices
6). Supervisory and user
through the internet with
Dver the ROW, the actual
ined from the positioning
of occurrence is sent via
d gateway. Consequently,
mge messages among a
met. At the same time it
;nsors. A server reads the
n analyzer. Moreover, the
mshes it to the receiver.
>n on whether the corridor
end, results are sent to the
;met gateway or mobile
es and scanner, a pipeline
the ground based remote
sensing technique. Figure 8 shows top level schema of three
simple steps from receiving signal and extracting process aim
to detect moving object over corridor and to make warning
about intrusion.
Figure 8. Top Level Framework
As it’s mentioned on earlier paragraph and depicted in figure 9,
receiver input signal consist of data from sensor, reference data
which calls pattern data and feedback from the previous
records. The next step, of the extracting moving object has
three functions of revealing, de-noising and detection. This step
is usually programmed based on different remote sensing
application. The last step consists in the function of making
warn about intmsion to decision maker, estimation and event
history. Finally event history makes feed back to first step.
Receiver Input signal Extracting Moving Object Moving Object
Figure 9. Classification Schema
Image and data that are gathered recently will be compared to
the reference. For instance, if hardware processes just a few
points (no more than 5), because there is high flow rate of data,
we need a lot of time and expensive hardware. For this reason
and according to the Figure 10 the problem with scanners
especially LADAR is considered in three components.
Figure 10: Process of Object Detection schema
The first component is Classification and Filtering Process. As
far as this technique is supposed to helps us to concern certain
point instead of all the point in the corridor. Figure 10 shows
how Classification and Filtering can reduce the time to
producing report and the size of its. To put it another way,
system is looking for the similarities between recent data and
reference. For this reason the elimination of the frequent data
interaction will take into consideration. Secondly, to reduce the
process time Defining Reference process is introduced.
Additionally, Discrimination technique is of assistance
software to match recent data with typical shape and suitable
format for moving and static objects. For instance, red colour
and green can assign to moving and static objects respectively.
On the other hand, it is possible to identify whether it is human
or device? What it looks like. Regarding to the power of code,
it is also possible to recognize the dimension of objects.
For the computation of optical flow of 2D image motion the
following (Yokoyama and Poggio 2000) function is presented:
/ (x, t) . I (x + dx,t + dt) (1)
Where /Ci, t) = the spatiotemporal function of image
intensity
^ = intensity of the time
t + dt = object is assumed to remain the same
For instance; no illumination change are supposed to occur.
Equation 1 can be expanded using Taylor order as follows:
\/ T l.v+ lt= 0 (2)
Where ^ ~ ^ x ‘ = the gradient
it = temporal derivative of i (•*• O
^ = = image velocity
According to the (Barron, Fleet et al. 1994) one linear equation
is insufficient to determine 2D velocity that is known as
aperture problem. However it seems good enough to detect
moving objects. For instance, moving object on geometric
shape, (such as line circle, rectangular and....), indicates
intrusion activities.
3.2 Detecting Object
It is defined the similarity between an object of previous frame
Rprov C r 0 and an object of current frame ^c«r( ra ),
using estimated position of lines by optical flow.
{Pjlf A(n)}6 5
Equation (Bernhard Gruber SW. Location Based Services using
a Database Federation. Institute for Geoinformation) is
Detected and stored line of the current frame.
{5 4 1 S*(¿Vim )} 6 Rfprev (m) (4)
Whereas equation (4) is defined all background line as a
previous frame, then similarity is defined as follows:
p(wi, m)
y n ; ,
r£[s,l
Where l“*/ I
two objects
u
(5)
then these
is the number of element in S, and '’iJ
Rprtvtmyand R eur (m ) are considered as
the same object if the similarity of pOn.m )
value.
is non-zero
t il if Pi* R C ur{m) where P t € 5 ;
lj to otherwise . (6)
RpreArni = R cur (m ),if p(m,m r ) * 0.