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Automotive Lane Tracker Home

Automotive Lane Tracker as part of DOT/NHTSA's DASCAR Project & Beyond

------- T O C --------- 

Summary of Features
History of development
-Delivery of prototype

Other's Approaches 
Need for Lane Trackers
The Future

Features List
Performance Specs
System Components

Next Generation Version

-Next Gen: Closer Look

NIR LASER illuminates pavement on alternate scans; <p> the resulting target image derives from the difference.
move your mouse over image for animation

---------- 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).

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. 

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! 

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. 

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.


--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.

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."

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.


 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. 

---------- 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: ---------- 

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


 Copyright 1999 2000  2001  2002  Web Author: Glen A. Williamson  webmaster@williamson-labs.com

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