Description

Introduction

Various Departments of Transportation (DOTs), both nationally and internationally, are developing and incorporating automated road quality inspection equipment. “It is well known that the characteristics of the road surface, especially for the surface layer, are essential to satisfy some primary requests, such as user safety and noise pollution. Road performances are being evaluated and classified by the adoption of certain parameters that affect various characteristics of the road, one of which is the surface texture; it is strictly related also to the tire-road contact.1

The issue

Road inspection is notoriously challenging due to dynamic changes in reflectivity of the road aggregate, cracks, expansion joints and bright sunlight. High sampling rates are needed to be able to see and record the road surface profile as the inspection vehicle drives at normal speed.

Laser Road Quality Measurement

The solution

The Microtrak™ series laser scanner from MTI Instruments incorporates high speed, line scan, and CMOS sensors that sample at up to 40,000 samples per second. While a dichroic filter cuts down on ambient light, a high-speed closed loop servo controls the intensity of the laser to optimize for average road conditions.

Road Quality Laser Measurement - laser mounted under vehicle

The cut time feature detects loss of signal where the laser spot falls into a crack and the line scan sensor can’t detect a return. In this event, the laser sensor processor automatically holds the last known value for a short period of time (user programmable) until the laser spot on the road surface again becomes visible. Typically, the LTS-300-200 laser sensor head is the best choice due to its 300 mm standoff and 200 mm measuring range. The laser heads are IP-67 sealed against the environment and can tolerate up to 16 G’s of vibration.

Let our application engineers put you on the road with the Microtrak™.

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