Institut National D'optique

Systemes Pavemetrics Inc.

John Laurent

Michel Doucet

Denis Boulanger

Richard Habel

Mario Talbot

Measuring a distance to a surface while compensating for variations in a transverse position and/or low speed displacement of the instrument. One method includes retrieving a predetermined transversal distance from a longitudinal feature at which to extract a relevant distance; retrieving a distance set; retrieving a position of the longitudinal feature relative to the distance set; extracting a range point at the predetermined transversal distance from the longitudinal feature; adding the extracted point to a longitudinal distance set. In another method, if two sensors are provided with an overlap in the transversal direction, extracting a range point at a predetermined transversal position; adding the extracted range point to a longitudinal distance set; retrieving a pitch angle of the instrument; calculating a local slope of the surface using an overlapping transversal point, the pitch angle and the separation length; calculating a height variation using the local slope and a longitudinal separation.

Method and apparatus for compensating lateral displacements and low speed variations in the measure of a longitudinal profile of a surface

There is provided a vision system and a method for scanning a traveling surface such a road to detect surface defects thereof such as cracks. The vision system, which is mountable on a vehicle, is provided with a linear imaging system for imaging successive adjacent transversal linear portions of the traveling surface as the vehicle advances. The vision system is also provided with laser line projecting means angularly projecting a laser line onto the transversal linear portion of the traveling surface to be imaged in a substantially coplanar relationship with the linear imaging system. The present vision system is particularly devised to be immune to surrounding light conditions variations to provide optimum cracks image contrast for both transverse and longitudinal cracks.

Vision system and a method for scanning a traveling surface to detect surface defects thereof

An apparatus for sensing position data of a light pattern created by a known light source on an object, comprising an optical system for collecting an incident light beam of the light pattern and transmitting the incident light beam to a beam splitter. The beam splitter has a known reflection/transmission ratio, such that the incident light beam from the light pattern received on the surface of the beam splitter results in a transmission channel, transmitted through the beam splitter, and a reflective channel, reflected from the beam splitter, with intensities of the transmission channel and the reflective channel varying as a function of a position of the incident light beam on the surface of the beam splitter. Detectors detect the intensities of the reflective channel and of the transmission channels. Dimensions of points of the light pattern on the object are calculable as a function of the intensity of the reflective channel and of the intensity of the transmission channel.

Position-sensing device for 3-D profilometers

A sensor and method for taking range measurements of a target object using a TDI device as a detector are provided. The device is positioned to detect reflections of a structured light beam on the target object. To avoid losing the range information in the TDI process, the exposition of the device to the reflection of the light beam is restricted to the first integration period of the acquisition cycle of the TDI device, so that the output of the device provides line by line an image of the light beam on the target object during this first integration period.

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Saint-Augustin-de-Desmaures, Canada

John Laurent