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Automotive
Lane Tracker Home
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| Automotive
Lane Tracker as part
of DOT/NHTSA's DASCAR
Project & Beyond |
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T O C ---------
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---------- SUMMARY
of FEATURES: ----------
* Operates Day and Night.
* Line Position Update every 1/2 inch @ 60 MPH.
* Vehicle Shadow/Line-boundary confusion eliminated.
* Line Position Accuracy = 0.5%
* Ambient light cancellation 30dB avg.
* Multiple Line Tracking.
* Road-Edge Tracking.
* Motion artifact suppression > 35dB.
* Auto Exposure: Electronic.
* Compact design: not visible to drivers.
* Optional: Scanning "Barcoded" Line Data.
* Inexpensive: projected cost of manufacture < $310.00 @ 9k units
(excluding NRE).
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Design
Paradigm:
The
design is still viable for certain applications that require speed of detection,
high resolution, accuracy, and most importantly, Reliability.
This design uses hardwired logic
as opposed to the "Stored Program" Control (DSP, CPU, etc.) approach--albeit,
it is Host supervised.
The reason for this approach, is
its inherent superior Reliability (no blue screens), as well as Speed,
and it is very cost effective.
Also, since the controlling functions
will be implemented in an FPLA (Field Programmable Logic Array), updates,
threshold and coefficient changes (even, conditional branching) can be
made on the fly.
There is no CPU bound image processing
required; the final absolute lane position data value is instantaneously
available, the are no calculations or LUTs (look Up Table) required.
In fact, the data value (lateral
position) delivered, is from the center of the highway marking (white/yellow
line), regardless of its width; this feature also aids in detecting the
roadway edge boundaries where there is no white/yellow line.
Finally, it is also capable of detecting
multiple lines or boundaries.
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An Application:
Each year there are thousands of highway deaths and tens of thousands of
serious injuries due to "Run-Off-Road" accidents.
Everything from simple driver inattentiveness, to fatigue, to driving-while-impaired,
are responsible.
The cost to the nation is the thousands of lives lost, and tens of
Billions of dollars.
This is a much more common cause of single vehicle fatalities than is
generally thought. The high profile multiple vehicle accidents--including
large "eighteen wheelers," capture the headlines.
One very effective prevention to this needless carnage, is the installation
of so-called, "Rumble Strips" along the roadway edge.
Rumble strips are deep, regularly spaced grooves cut into the pavement
along the roadway edge--orthogonal to the vehicle's direction of travel.
--alerting drivers in a very sudden and "Upright" way.
As the vehicle approaches the near-edge of the roadway and the vehicle's
tires encounter the grooves, there is a sudden and immediate BUZZING! sound
telegraphed up the steering column, as well as, throughout the entire vehicle.
In all but the most impaired driver, the response is imminent and Life
Saving!
TOP
As effective and proven as Rumble Strips are, the task of implementing,
and maintaining this feature on the nation's vast highway infrastructure
will be enormous. Besides the installation costs the maintenance costs
of the roadway will be increased due to the fast deterioration of the roadway
edge (reduced resistance to wear due to the grooving). Also there is accelerated
tire wear, on the vehicle's right hand side tires.
Enter the "Virtual Rumble Strip" The use of a device on the vehicle
that can continuously monitor the vehicle's Lateral Position on the roadway
could signal the driver's predicted run-off in time to prevent
The concept of the "Virtual Rumble Strip," as a preventative measure
against the thousands of "run-off" highway accidents is enormous. If this
concept proves to be effective, the need for OEM lane trackers could even
reach the family automobile. |
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--Development--
In the intervening time, development was delayed due to a modification
in NHTSA's requirements, i.e., in addition to detecting and tracking the
retroreflective White/Yellow Lines, it was determined that there was a
need to detect and track non-retroreflective plain painted lines, as well.
Needless to say, this increased the difficulty of what was already
a difficult task, hence the added delay in delivery and testing of the
prototype.
--Prototype Delivery--
In early September, of last year, the prototype was delivered to
VTRC near Marysville, Ohio, where it was tested and accepted. At that time
there were negotiations started for the follow-on next generation version,
that would be suitable for manufacture.
However, it is my understanding, that because of budgetary allocations
within NHTSA, that the design and manufacture of the next generation units
is on indefinite Hold.
This is indeed unfortunate, because the design and application of
this lane tracker's unique technology offers a robust and inexpensive answer
to a problem that has plagued highway instrumentation specialists for years.
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--Other's Attempts--
In recent times, the other attempts at lane tracking (Lateral Position
Monitoring) have sought to utilize video cameras, DSP hardware with Image
Recognition software to solve the problem.
Aside from the latency caused by the video camera's frame rate--18
inches per sample @ 60 MPH --the image processing time limits any Real
Time use of this approach.
NTHSA's original requirement was for the lane tracker as an instrumentation
device, but DASCAR's creator, insisted--among other things--that it be
manufacturable and inexpensive. We believe that we succeeded in that requirement.
--Need--
Presently there is a genuine need for reliable, fast and relatively
inexpensive lane trackers as sensors for Vehicle Safety Systems on fleet
vehicles--especially large trucks.
The concept of the "Virtual Rumble Strip," as a preventative measure
against the thousands of "run-off" highway accidents is enormous. If this
concept proves to be effective, the need for OEM lane trackers could even
reach the family automobile. However, on this subject, I'm sure I am "preaching
to the choir."
--Future--
The technology and intellectual property related to the present
embodiment of the Lane Tracker, has always been and remains, the property
of Williamson Associates.
There is still development work required to make the Lane Tracker
a manufacturable device. |
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| ---------- PERFORMANCE
SPECIFICATIONS: ----------
1).. Detects white and yellow retroreflective and non-retroreflective
lines: Day and Night.
2).. Line Position Data: every 1/2 inch @ 60 MPH. (Design supports
sample every 1/10 inch @ 60MPH.)
3).. Vehicle Shadow/Line-boundary confusion is completely eliminated
by the systems ambient light cancellation scheme.
4).. Resolution: Line Position Accuracy--after calibration
= 0.5% of total scanned distance--worst case (orthogonal to the direction
of travel).
5).. Ambient light (sun light, etc.) cancellation > 12dB worst
case; average = 30dB. (measurement made with AGC = off.)
6).. Motion artifact suppression, > 35dB (all conditions)
7).. Line Beginning and Ending acquisition error < 1/2 inch
at 60 MPH.
8).. Auto Exposure: electronic auto exposure control by adaptive
scan rate. Errors due to rapid shadow entry/exit are eliminated by the
fast electronic exposure control and our artifact prediction & lockout.
9).. Multiple Line Detection & Tracking is supported (presently
it is using 2nd line lockout, detecting and tracking only a single line).
10).. Road-Edge Only Detection: the system is capable of detecting
the roadway edge/shoulder boundary--useful in the absence of line markings.
11).. System design allows the possible reading of embedded (invisible)
"barcoded" data in the white lines, conveying pertinent roadway information
such as: speed limit, "safe" speed limit; new construction advisory, etc.
(a.. Also, active programmable barcoding devices could be placed
at critical locations conveying real-time information: accident notification,
road surface icing alerts, etc.
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| ---------- SYSTEM
COMPONENTS: ----------
A.. Camera: The camera is a compact, all weather design, consisting
of a CCD Sensor Array and LASER Illuminator combination, which is normally
enclosed in the vehicle's side mirror nacelle.
B.. Host Interface and Controller subsystem: The system architecture
is based on Host control; however, for ease of troubleshooting it can run
autonomously, allowing easier hardware/software conflict resolution. |
| ---------- NEXT GENERATION:
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The present system consists of about 50 ICs, half analog and half
digital.
The next generation system will consist of two ICs: aside from the
CCD linear array, there will be one 12 bit Flash ADC--located in the camera
head, and one custom ASIC serving as the controller and Host interface.
Next
Gen: Closer Look
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Copyright 1999 2000 2001 2002
Web Author: Glen A. Williamson webmaster@williamson-labs.com
Suggestions are Solicited, P l e a s e !
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