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3D Scanning
Client specific surveys Traditionally datasets captured are based on discreet points. Discreet point datasets must be fully specified by the be client and thoroughly understood by the field surveyor. Any missed or faulty data or a change in specification from the client requires a revisit by the surveyor. During the life time of a project areas will be resurveyed many times to suit the particular needs of different specialists.		Architect >> Specialised survey Structural Engineer >> Specialised survey Civil Engineer >> Specialised survey Asset Management >> Specialised survey
Central disseminator of spatial information Scan data is multidiscipline – the information rich data set can be manipulated to meet the needs of many specialists. New information can be extracted from the data set at any time during the entire life of a project. If managed properly it becomes a central disseminator of information.		Architect << Scan Data Set Structural Engineer << Civil Engineer << Asset Management <<
High-Definition Surveying Systems The added value to deliverable products has encouraged investment into a new generation of 3D Scanners.
Leica HDS 3000 • Time of flight laser distance measurement • Laser beam is swept vertically by mirrors and rotates around Horizontally Plane • Dual windows allow 360º x 270º field of view compared to the tradition 45º x 45º • Over 1200 points are measured each second • 6mm positional accuracy at 50m • Point capture up to 200m away • User-specified scan area and density, data filtering, scan scripting and automatic target recognition facilitate intelligent data capture • Automatically calibrated photo overlays • Software allows much larger data sets to be manipulated, necessary from the 20 million plus points created from a 360º scan
Leica HDS 4500 • Phase difference distance measurement from a continuous beam • Laser beam rotates around both horizontal and vertical plane 360º - 310º field of view • Ultra-high speed – from 100,000 to 500,000 points per second • Accuracy of 5mm at normal range • Short range – maximum distance 50m
ABA developing Kinematic 3D Scanning The system known as the GRP5000 combines the HDS4500 and Leica GRP 100 rail trolley.The scanner is mounted on the trolley and fixed perpendicular to the track. The beam rotates at 33 scans per second and records10,000 points per revolution. Integrated sensors for chainage, gauge, cant and time measurement: • Chainage accuracy: 2cm • Gauge measurement accuracy: 0.3mm • Cant measurement accuracy: 0.1mm • Time stamped every: 20mm
Graphical interface allows full measurement control Density of measurement - The speed at which the trolley is pushed along the track determines the density of the scan. 1km/hr represents a progression along the track of 8mm ensuring all detail is picked up. - Chainage-specific profiles can be scanned by remaining stationary for just a few seconds. The user specifies the reference stationing The actual cross section measurement is shown in real time. This can be compared to a clearance profile. A radio modem within the trolley allows operator to control tracking devices from the keyboard.
Coordinating scan data Data is acquired as either: Relative Measurements • Profiles are measured relative to the track positions • Given the true position of the track the real world coordinates of data can be calculated during post processing Absolute Measurements • Full survey of track axis with absolute 3D coordinates in real time • The actual position of the trolley is tracked with total stations using automatic target tracking or GPS and transferred via the radio modem to the laptop • Simultaneously all the sensor values are measured and all the information is stored. The computed track position is calculated and displayed in real time
Processing Massive amounts of storage capacity are required. At 1.5 MB of data recorded in one second approximately 500 MB of raw data per 100m is stored. Software allows the scan to be viewed with a deroled projection at almost photo resolution and profiles can be extracted at any chainage.
Cross Section at Ch 590.000 3d measured data can be easily viewed in psuedo-photographic form.
Cross Section at Ch 625.000 Every detail appearing in the scan is measured to millimetre accuracy.
3D View of St. James’s Park station Ch 628 – Ch 640 Continuous kinematic scanning builds into a dimensionally accurate virtual world.
Clash detection A clearance map can be overlayed on the projection to highlight clashes.
Data extraction Spatial information from any point with in the scan area can be directly extracted from the data base. Extracted data can be presented as a full 3D wire frame or 2D profiles in any format required by the client. (AutoCAD, MOSS, ClearRoute, ASCII). Minimum or Maximum Profiles over a given chainage. The greyscale images and clash detection reports can be directly annotated and delivered in a number of packages.
Why Kinematic Scanning? Productivity Track Survey at 1km per hour Accuracy Accuracy comparable with other survey methods Density No detail is left out, everything is measured, including adjacent rail Access The portable and light weight design allows easy access Clash Detection Given an envelope clash detection can viewed in real time and later presented visually Multidiscipline Extra information can be extracted at any time for different professionals Asset Management High resolution image provides a permanent record of all track side infrastructure Flexible outputs Spatial information can be tailored to client's need
View the evolution to 3D Scanning >>