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PavemetricsSoftware and Hardwareimprovements using 1mmx 1mm resolution 3D roadsurface dataVision Technology for Inspection of Transportation InfrastructuresPAVEMETRICS Systems Inc.150 Boulevard René-Lévesque Est, Suite 1820Québec, Québec, CANADAG1R 5B1www.pavemetrics.com

PavemetricsPavemetrics: Sensors forInfrastructure Inspection Founded 2009; a “Spinoff” of Canada’sNational Optics Institute(INO)3D sensor developmentAutomated dataprocessing algorithmdevelopmentTechnology used forRoads, Runways, Rails,Tunnels (400 systems)40 countries2

PavemetricsTechnologies Offered LCMS LRIS - Line Scan Imaging LRMS – Rut measurementsystem3

PavemetricsTechnologies Offered LCMS LRIS - Line Scan Imaging LRMS – Rut measurementsystem4

PavemetricsTechnologies OfferedLCMS - 25

PavemetricsAPPLICATION: Roads6

PavemetricsSpecificationsLCMS-1 vs LCMS - 2SpecificationsLCMS -1LCMS-2Acquisition Rate5,600 profiles/s28,000 profiles/sRange Accuracy/Resolution0.5mm / 0.25mm0.25mm / 0.05mm*Lateral Resolution1mm1mmField of View (lateral)4m4mData rate per km0.6 Gb/km3 Gb/km7

PavemetricsStorage needsSpecificationsLCMS-2Data rate per km3Gb/km10,000 mile network48Tb16 units x 50 8008

PavemetricsImproved vertical resolution ASTM and AASHTO standards utilized by the road profiling industry(ASTM E950, AASHTO M328, 56, 57) require the use of sensors witha vertical resolution of 0.05 mm or greater. vertical resolution specifications previously published byPavemetrics for the LCMS were not based on comparable testmethods adopted by other line lasers (RoLine, Gocator) currentlyaccepted in the industry.9

PavemetricsGocator model 2342A-3B-12Resolution and Test MethodLMI Gocator 2300 & 2880 Series User Manual,Document revision: D The vertical resolution (Z)of the Gocator is reportedas 0.013 – 0.037 mm Selcom’s test to determineresolution involves multiplescans of an object with adiffuse, painted whitesurface (a calibrationtarget) Resolution is defined as the“maximum variability ofheight measurementsacross multiple frames,with a 95% confidence”10

PavemetricsLCMS Resolution EvaluationProcedure 1/3 The objective of thePavemetrics’ test was tolikewise establish resolutionby determining the “maximumvariability of heightmeasurements across multipleframes, with a 95%confidence” The first step in the evaluationwas to create a similarcalibration target The Pavemetrics-developedtarget is a precision-machinedcylinder with a diffuse, paintedsurfaceClose-up View of Pavemetrics’ CalibrationTarget11

PavemetricsLCMS Resolution EvaluationProcedure 2/3 A computer-controlled, highaccuracy, translation table was thenused to control the position of thecalibration target/object in relation tothe LCMS The LCMS is setup to scan within itsworking range and is initialized forscanning the target While the LCMS was scanning, thetranslation table was used to movethe target away from the sensor at astep distance of 0.05 mm This movement produced a change invertical distance (of 0.05 mm) whichthe LCMS was used to measureComputer-controlled TranslationTable12

PavemetricsLCMS Resolution EvaluationProcedure 3/3 The cylinder was put into rotation in order tosimulate the motion of a vehicle. LCMS height/distance measurements were madeacross multiple frames with outputs at 1 inchintervals with the LCMS. Likewise, the variability of height measurementsmade across multiple frames was then analyzed The analysis established the maximum variability ofheight measurements made by the LCMS acrossmultiple frames to be 0.012-0.042 mm at aconfidence level of 95%13

PavemetricsLCMS-2 – Crack detection Same road sections were scanned with boththe LCMS 1 and LCMS 2 LCMS 1 scans were at the standard 5mminterval LCMS 2 scans were at 5mm, 2mm and 1mmfor comparison purposes14

PavemetricsExample 1 – 5mm LCMS 115

PavemetricsExample 1 – 5mm LCMS 216

PavemetricsExample 1 – 2mm LCMS 217

PavemetricsExample 1 – 1mm LCMS 218

LCMS 2 – 1MMLCMS 2 – 2MMLCMS 2 – 5MMLCMS 1 – 5MMPavemetricsExample 1 – AllConfigurations19

PavemetricsExample 2 – 5mm LCMS 120

PavemetricsExample 2 – 5mm LCMS 221

PavemetricsExample 2 – 2mm LCMS 222

PavemetricsExample 2 – 1mm LCMS 223

LCMS 2 – 1MMLCMS 2 – 2MMLCMS 2 – 5MMLCMS 1 – 5MMPavemetricsExample 2 – AllConfigurations24

PavemetricsExample 3 – 5mm LCMS 125

PavemetricsExample 3 – 5mm LCMS 226

PavemetricsExample 3 – 2mm LCMS 227

PavemetricsExample 3 – 1mm LCMS 228

LCMS 2 – 1MMLCMS 2 – 2MMLCMS 2 – 5MMLCMS 1 – 5MMPavemetricsExample 3 – AllConfigurations29

PavemetricsExample 4 – 5mm LCMS 130

PavemetricsExample 4 – 5mm LCMS 231

PavemetricsExample 4 – 2mm LCMS 232

PavemetricsExample 4 – 1mm LCMS 233

LCMS 2 – 1MMLCMS 2 – 2MMLCMS 2 – 5MMLCMS 1 – 5MMPavemetricsExample 4 – AllConfigurations34

PavemetricsLCMS-2 – Crack detection The LCMS 2 provides more complete crack detectionand is more sensitive to finer cracks Improvements are apparent even if you operate anLCMS 2 using a 5mm collection interval However 2mm and 1mm intervals will furtherimprove results35

PavemetricsNew Feature – Man madeobject detectionOpen ManholeCoverClosed ManholeCoverStorm-drain36

PavemetricsProblem (Example 1)Total Crackingis 3.2 meters( 10.5 feet);100% is falsecracking This pavement is inexcellent shape; not a crackto be seen However, there is a smallbreak in the surface aroundthe edge of the manholecover This generates 3.2 m offalse cracking 100% of this cracking isfalse37

PavemetricsSolution We deliberately detectthe MMO first in orderto exclude it fromcrack detection This also allows us toadd value byinventorying it Now the crackingquantity here is 0meters; which iscorrect38

PavemetricsData That Are Reported Bounding box: the X, Y location of box which is drawn aroundthe detected object (can relate back to GPS and milepoint) Area: the calculated area of the object Radius: only reported for manholes, radius of the manhole Width and Height: width and height of the drain or its boundingbox Perimeter: list of points that form the perimeter of the object,useful for highlighting the object in images used for reporting Type: two types reported at present; closed manhole or stormdrain/open man-hole39

PavemetricsLCMSRoadInspect InterfaceType: 0 (Closed Manhole)Bounding Box Height: 2.9 feetBounding Box Width: 2.9 feetRadius: 1.4 feetLocation: 3.6 meters in X and 6.4 in Y.40

PavemetricsExample 2: Without MMODetectionTotal Crackingis 5 meters( 16 feet);100% is falsecracking41

PavemetricsExample 2: With MMODetection42

PavemetricsExample 3: Without MMODetectionTotal Crackingis 6.35 meters;false crackingis 4.07m.180% overreporting.43

PavemetricsExample 3: With MMODetection44

PavemetricsExample 4: Without MMODetectionTotal Crackingis 23.79meters; falsecracking is1.66m.8% overreporting.45

PavemetricsExample 4: With MMODetection46

PavemetricsLCMS-2 Laser class47

PavemetricsLCMS-2 Laser class48

PavemetricsRunway 08-26, Montmagny,QC

PavemetricsRunway 08-26, Montmagny,QC

PavemetricsRunway 08-26, Montmagny,QC900 m30 m

PavemetricsSurvey SpecificationsTotal length of runway: 900 metersTotal width of runway: 30 meters6 surveyed control points were used (3 on each end of the runway)44 surveyed test points were distributed over the entire runway surface.Total survey time 15 minutesTotal survey length 12kmNumber of scans used to cover runway surface: 11* (total in bothdirections)*A large number of scans were used to insure overlap between runs

PavemetricsSurvey (11 runs with approx.1m overlap between runs)Run 3Run 2900 mRun 1Ctrl. pointOverlap zone349 points de collageOverlap zone

PavemetricsTie Points (every 40m)349 tie points were automatically generated and used to automatically stitch the 11 runs

PavemetricsTie Points

PavemetricsControl Points6 surveyed control points (located on the ends of the runway) were used to align the Pavemetrics data to the traditional survey

PavemetricsControl Points (manual)Green: Position of control point beforealignment.Orange: Alignment pointGreen: Position of control point afteralignment

PavemetricsRunway 08-26 - result30 m900 metres

PavemetricsRunway 08-26 - result

PavemetricsRunway 08-26 - result

PavemetricsAccuracy AnalysisThe accuracy of the LDTM solution was evaluatedusing 44 survey targets which were painted on therunwayDue to the shape of the painted targets X, Ycoordinates were difficult to match, howeverelevation data (Z) was excellentWhat wewanted!What we got!

PavemetricsSurvey Target LocationsOverlaid on Pavemetrics’ DataSurveyed test points used to evaluate the accuracy of the LDTM solution

PavemetricsAccuracy analysisRTK Base GNSS used for the post-processing Base station was in La Pocatière, QC which is 62 km from the siteSurvey time was only 15 minutesData preparation and processing time took 3 hoursThe entire runway LDTM surface data was then alignedto the 44 surveyed points using a best fit algorithm inorder to minimise overall errors

PavemetricsConclusionsAccuracy versus survey results:Average RMS Error [X; Y; Z] [0.016; 0.011; 0.003]mAs expected X, Y accuracy was lower because of shape ofpainted survey markers.Elevation accuracy was an amazing 3mm overall!

PavemetricsLAS file output (10cm x10cm)

PavemetricsQuestions ?66

Gocator model 2342A-3B-12 Resolution and Test Method The vertical resolution (Z) of the Gocator is reported as 0.013 -0.037 mm Selcom's test to determine resolution involves multiple scans of an object with a diffuse, painted white surface (a calibration target) Resolution is defined as the "maximum variability of height .