How to reduce Blind Spots

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How to reduce Blind Spots Powered By Docstoc
					2009


   How to reduce Blind
   Spots




               Bebiana Macedo
                   Nr. 1548832
                     23-01-2009
Table of contents
Abstract ......................................................................................................................................... 3
Introduction .................................................................................................................................. 4
Part 1 – Blind spot areas ............................................................................................................... 5
(Automobile view) ......................................................................................................................... 5
Part 2 – Solutions Analyses ........................................................................................................... 8
       How to correctly set mirrors to avoid blind spots ............................................................ 8
       Vehicles’ technological Solutions ....................................................................................... 9
       Cameras’ solution.................................................................................................................. 9
       Sensors’ solution ................................................................................................................. 10
       Improvements on road design.......................................................................................... 11
Part 3 – Discussion ...................................................................................................................... 13
References................................................................................................................................... 15




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Abstract:
        This essay features a discussion about a great danger that emerges on traffic
along roads, which is the existence of blind spots. The objective of this research is the
evaluation of the present situation, analyzing possible improvements on vehicles, road
design and human behaviour, in order to avoid accidents caused by the existence of
these blind zones. Therefore, the solutions that this essay describes are focused on
mirror’s adjustment, technological systems (i.e. cameras and sensors), and
intersections design improvements. However, as this problem has a vast array of
solutions, there are a lot of dissimilar opinions about which one should be applied or
which aggregation of different resorts. Consequently, it is difficult to draw consistent,
effective and irrefutable conclusions without further research. The data used in this
essay is based mainly in the work done by (Sotelo & Barriga, 2008), (Blanc & Steux,
2007), (Kiefer & Hankey, 2007) and (Kojima, Sato, Ohta, Taya & Kameda, 2005).




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Introduction:
       In the current day and age, and considering the growing enlargement in motor
vehicles use, it is not possible to ignore the problems of safety in transportation,
making it imperative to develop means to respond to its hazards. This essay focuses on
the research and analysis of methods to counter the immense blind spot issue, as it is
considered one of the great causes of traffic accidents.

        The term blind spot can be utilized in various and distinct perspectives like in
Anatomy, where it is seen as the area in the retina of the eye which is insensitive to
light; Radar Transmissions, to refer to areas where the reception of wave’s information
is poor; or in an Automobile view, where blind spot zones are the regions or directions
in which vision is obscured, that is, areas on which drivers cannot make a good
assessment of the surrounding situation – what is happening and who or what is
nearby – rendering any action possibly prejudicial, and extremely dangerous.

        In this essay, the perspective of Blind Spot that will be explored is the
Automobile view, where the existence of these areas is a huge danger for traffic
circulation. Nowadays, the number of accidents, and people injured on them, caused
by the existence of these regions is so large that it is imperative to reflect about the
issue, and develop techniques to prevent further accidents, in a timely fashion.

       This blind spot matter can be analyzed either by investigating it from driver’s
point of view, inside the vehicle, or by examining the road design, in particular the
intersections drawings.

        This essay will present a literature review, and subsequent analysis on some of
the solutions presently available for the two problems approaches mentioned above,
including its operational methodologies and results (on part two). Furthermore, it will
draw conclusions about the matter at hand and its presented outcomes, including
possible improvements (on part three), in order to answer the research question in the
basis of this article:

           Is it possible to develop the road and car’s facilities in order to
                           reduce the blind spot areas?




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Part 1 – Blind spot areas
(Automobile view)

         Blind spots can be defined as areas around a vehicle which cannot be seen by a
driver while seated in his regular driving position, either by occlusion of the field-of-
view, by the vehicle’s support pillar, when looking through the windshield (as
illustrated on Figure 1), or by scanning the vehicle’s rear and side view mirrors, without
turning the head to view the area directly.




                     Figure 1 – In red blind spot created from car’s support pillar




        The traditional vehicles’ mirrors position may originate large blind spot zones,
like the ones displayed on Figure 2. The major problem that emerges with the
existence of these invisible areas occurs during lane changes, when the driver has to
remark and check in an appropriate mean all that is surrounding him to have
situational awareness, while manoeuvring the vehicle, in order to avert a potential
collision.




                    Figure 2 – Settings of visibility of traditional mirrors positions




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       Moreover, the vehicle’s dimension also influences the length and extension of
blind spot areas in all directions (rear, front and side, as in Figure 3). Larger vehicles
produce larger areas of obstructed view. For example, the traffic advisory for
passenger cars that are circulating behind trucks is not to follow too close to them, in
order of trying to avoid enter in the large rear blind spot zone that exists behind them.
In general, to circulate in a safe way, small vehicles should leave the space equivalent
to 4 cars between the one in front and the one behind, however when the one in the
front is a sizable vehicle, like a truck, these space should be greater, typically
corresponding to 20-25 car lengths.




                                 Figure 3 – Truck’s blind spot




        Furthermore, and at the present time, most of the accidents inside urban
centres occur in road intersections which have areas of hindered vision, the so called
blind spot areas. This is caused either by vehicles in an erroneous position or with large
dimensions (like in Figure 4), or by an improper road design which makes the
perception of the situation at the crossing exceedingly difficult. In addition, other kind

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of common collisions, which normally take place in urban intersections, due to blind
zones, are motor vehicles/bicycles collisions.




               Figure 4 – Example of an intersection Blind spot caused by a large vehicle




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Part 2 – Solutions Analyses
       Currently there are several studies addressing the blind spot problem from
many different approaches, for instance, on how to correctly position the vehicle’s
mirrors, and on technological solutions to enhance the spatial perception of the driver,
namely during lane changes, or even studies about possible improvements in
intersections facilities.



       How to correctly set mirrors to avoid blind spots:
       The easiest way to prevent blind spots is having the car’s mirrors under the
correct adjustment.

        During driving lessons, students are often taught to set the outside mirrors in a
frame in which both sides of the car are visible. However, with the development of the
studies around the existence of blind zones, and how to avoid them, experts believe
that this is not the most suitable orientation for the mirrors. This method produces an
overlap between the area covered by the rear view mirror and the areas covered by
the outside view mirrors. With this configuration the view will be duplicated, when it
should be a complement between what is shown with the different mirrors, possibly
originating a blind zone big enough to hide an entire vehicle approaching from either
the rear or any side. As a result, the same experts consider that the accurate side
mirrors’ position is obtained by rotating both of them 15 degrees outward, as shown
on Figure 5. Like exposed on this figure, with this mirror’s configuration there is a large
reduction in the blind zones.

        In Figure 5, on the left side is depicted the visibility with the mirrors set in a
“traditional” position and on the right with the referred rotation.

        Moreover, with this modification drivers do not need to rotate their head so
far, nor to look over their shoulders, in order to see the traffic on the other lanes. It is
only required to glance on the outside and rear mirrors. (Technology News, May-June
2006)




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                      Figure 5 – Blind spot for different mirrors’ orientation




       Vehicles’ technological Solutions:
       Among vehicles’ technological solutions, there are numerous variants, which
include changes in car’s design, more explicitly: convex mirrors, microcontrollers,
radars, sensors and cameras. Most of these, already reached a select few market
segments.

       In this essay the vehicles’ technological solution analysed is focused on the
comparison between the utilization of cameras above the vehicles’ lateral/side mirrors
and their appropriate software, and sensors bellow vehicles’ side mirrors and at the
vehicles’ rear.

    There are many studies about how to employ these cameras’ and sensors’
alternatives, and they have already been applied by some car’s manufactures. So, all
the explanation that I will describe will take into account three articles written by
Sotelo & Barriga, 2008; Blanc & Steux, 2007; and Kiefer & Hankey, 2007 and the
implementation of it made by Volvo’s Fabricates.



       Cameras solution:
       The cameras solution has the purpose of visually detect the existence of
another vehicle or motorcycle on the driver's blind spot. This system is named vision-
based system for blind spot detection (BSD).

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        This cameras solution is a passive system that does not origin any interference
with other vehicles. It is also the most cost-effective and suitable solution for mass
automobile production.
        The BSD technique is composed by a digital camera, mounted above the lateral
mirror that captures 30 images per second, a computer system equipped with a
Pentium IV (running Linux software) and OpenCV libraries (where CV stands for
Computer Vision), and a driver’s front display. The system aims the detecting of
vehicles as well as motorcycles with the execution of a computer algorithm, and to
show the images obtained by the side-view camera, on the driver’s front display.
        The operation of this system is based on the analyses of camera images using
optical flow techniques, in order to detect pixels of vehicles that are moving in the
same direction as the vehicle in which the system is mounted on.
        These optical flow techniques are supported by a double phase detection
mechanism to grant vehicles recognition. At the first phase, a pre-detector system tries
to determine whether the detected cluster is a potential vehicle, according to the size
of the detected pixels. In the second step, another detector looks for the appearance
of vehicles’ frontal parts. Hence, any object looking like the frontal part of a vehicle is
considered as a probable vehicle.
        Therefore, this system gives the information of vehicles approaching to the
driver’s blind spot, in a range of 20m at its rear, being active at all speeds above
10Km/h, and detecting vehicles that are driven from a minimum of 20Km/h slower to a
maximum of 70Km/h faster.
        Nevertheless, this camera-based system has the same limitations as the human
eyes, so it will not function in conditions of poor visibility, for instance, during fog,
mist, or flying snow, but in such cases the driver receives a message alerting that the
system is non-operational. Furthermore, it will not react to parked cars, road barriers,
lampposts and other static objects. Besides, it is not suitable for the detection of
pedestrians, bicycles and small motorcycles, due to their short dimension when
compared with other vehicles.



       Sensors solution:
    On the other hand, there are the infrared and sensor-based methods that emit
beams or waves. These are active systems that provide mirrors light illumination when
identifying another potential vehicle in their blind area, the method is called effect of a
side blind zone alert (SBZA).

    The SBZA system employs infrared sensors set at vehicle’s rearview mirror and rear
bumper, and light emitting diodes (LEDs) mounted below the left and right outside
mirrors. These sensors cover a zone of approximately one lane over from both sides
and back of the vehicle. Their working method is based on the activation of the LEDs if
the driver switches on the turn signal, denoting his intention of going on either
direction. If the system detects a vehicle in the desired direction, it activates the red
LEDs on the appropriate side mirror and, simultaneously, an acoustic signal is
activated, notifying the driver of the presence of that other vehicle.

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    Nonetheless, this solution has some shortcomings as it may cause interference
with other vehicles equipped with devices alike, and cannot perceive rapidly
approaching vehicles, making it a poor warning system for lane changes. However, it is
a reasonable system for planning lane changes, as it gives indication of incoming
vehicles. In other words, it is an “unsafe warning system to change lanes but a safe
system to start the planning of a lane change” as it assists, but not substitute driver’s
attention, the use of a glance, the turning of the head above the shoulders, and the
employment of turn signals to show the intention of changing the lane. This system
makes possible, and helps the driver to make, an appropriate decision and execution
of a safe lane change.



        Improvements on road design:
       As the most number of traffic accidents inside cities’ centre occur in crossing
intersections, normally due to poor visibility, the majority of the studies made in order
to solve this problem have as possible solutions the utilization of roadside surveillance
cameras or the simple installation of traffic light signalization systems.

       Nowadays, there are frequently mirrors installed at a large number of urban
intersections that indirectly cover unsighted zones hidden by buildings, walls or
improper vehicle’s location. However, those traffic mirrors still have unsighted zones.
Hence, recent studies demonstrate that a possible improvement could be the
implementation of roadside surveillance cameras, the so called NaviView system.
(Kojima & Sato, 2005)

       These roadside surveillance cameras connected with virtual traffic mirrors will
show geometrically reshaped images based on Augmented Reality techniques, thus
permitting the drivers direct identification of vehicles coming from those unsighted
zones as early as possible, that is, with the utilization of this method drivers can have a
better perception of the traffic along the crossing intersections. By means of the video
treatment, the image displayed on the virtual mirrors is larger and clearer so the users
can shorten the delay for detection of coming vehicles in dead zones, effectively
reducing the number of traffic accidents at those crossing intersections and, of course,
ensuring their safety.

       In the mean time, a simpler way to figure out this kind of hazardous road design
that does not allow people to discern the incoming vehicles to the crossing
intersections, is installing traffic lights at all lane intersections to oblige drivers to stop
and wait for their turn to go ahead.

       Furthermore, it is essential to consider the bicycles’ problems at intersections.
A possible solution to avoid the dangerous situations that emerge from these crossing

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roads is the utilization of special lanes for this type of transportation, like exposed in
Figure 6. In this image, on the right is shown the normal intersection case where
bicycles circulate exactly in the same lanes as the other vehicles, whilst at the left is
shown the same intersection, providing special lanes used only by bicycles. This
improvement on traffic regulation brings added safety to this mean of transportation,
however it do not excuse the attention and respect of the laws from driver and cyclists
as every time that a manoeuvre like this is performed, there is always a risk associated
with it.




                         Figure 6 – Intersections for bicycles




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Part 3 – Discussion
       After all the research made to analyse if there is any possibility of reducing, as
much as possible, the subsistence of blind spots, results in a sizable number of
techniques, solutions and opinions.

         Most of those techniques are extremely connected, like for instance, the
utilization of cameras and sensors inside the vehicles, as both render possible the
detection of incoming vehicles and only differ in the way of presenting the results of
their analyses. The first solution shows the lead in a display on the front of the driver,
at its turn the second solution is based upon the activation of LEDs and audible
warning signals. On balance, to decide which one is the better it is needed to ponder
their advantages and disadvantages. As both of them are not infallible, I think that the
distinguish that can be made, to decide which one is the most appropriate and
efficient to fulfill the goal of preventing the blind spots, is looking at their difference on
detection rate and costs. So, I consider that the cameras’ system is the better one, as it
has a rate of correct detection of 99%, since the manufactures opinions is that they are
low price systems and still the fact of being a passive system that do not disturb other
vehicles. Nevertheless, the vehicles producers jointed these both techniques, as for
illustration Volvo made.

        However, the opinions about the choice on the enhanced method that should
be applied in vehicles or intersections, is not consensual by investigators, analysts,
governmental heads and automobiles’ producers as each one tries to “take the water
to its mill”. For example, while the manufactures of vehicles defends that the
improvements on vehicles’ equipment is the best alternative, most of the independent
analysts defend that the correct adjustment of vehicle’ mirrors is enough. In the mean
time, the governmental heads support the idea that improvements on road designs as
the implementation of duly co-ordinate traffic lights signals and the properly location
of consensual mirrors on intersections is sufficient, because these solutions are
cheaper, while investigators/scientists support the idea of mount and develop new
types of mirrors as they recover the visual display of the situation, nominated by the
use of virtual mirrors. Even so, the prime shortcoming of these mirrors is that they may
draw driver’s concentration too much and disturb their safe driving, working like a
distraction and not as a mean of preventing hazard situations.

        So, it is impossible to get a no doubt belief on which choice would be better,
but it is possible to ensure that there are enough and good choices to prevent the
blind spots, and then decrease the number of accidents mitigated by that zones,
increasing the safety on traffic transportation.




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         Attainment with all those conclusions, the answer obtained to this essay’s
research question is: yes, through the development made until these days, there are as
much as necessary barriers to prevent vehicles collisions and accidents provoked by
blind zones. However, it is needed to have in mind that the 100% of elimination of
blind spots is impossible, so the drivers must take the proper attention and precaution
while they are doing the hazardous manoeuvres, like change lanes or crossing roads
intersections and, even when their vehicles or the road design had been improved with
all or some of these new technologies, it is not endorsement a total reliability on them.




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 References:
Sotelo & Barriga. (2008). Blind spot detection using vision for automotive applications.
Paper presented at Journal of Zhejiang University SCIENCE A.

Blanc & Steux. (2007). LaRASideCam: a Fast and Robust Vision-Based Blindspot
Detection System

Kiefer & Hankey. (2007). Lane change behavior with a side blind zone alert system

Kojima, Sato, Ohta, Taya & Kameda. (2005). NaviView: Visual Assistance by Virtual
Mirrors at Blind Intersection

http://www.homesteadschools.com/traffic/course/Chap11.htm

http://en.wikipedia.org/wiki/Blind_spot_(automobile)

http://www.ctre.iastate.edu/pubs/tech_news/2005/may-jun/crash_analyses.htm

http://test-www.dmv.ca.gov/images/dlhdbk/dl600_img_33.jpg

http://www.wayward-volvo.org/drop/volvo_scc.html




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