MTRI deploys multiple sensors aboard its fleet of unmanned autonomous vehicles (UAVs) to collect critical project data.
Optical Cameras
To enable high-resolution Structure-from-Motion photogrammetry, we currently focus
on the Nikon D800
series of cameras, including the 36 mp Nikon D800/D810 and the 45.7 mp Nikon D850,
most frequently
using a 50mm prime lens. From distances in the 25-30m range (80-100 feet), this enables
sub-cm 3D
sensing useful for high resolution assessment of transportation infrastructure such
as roads and bridges.
Other UAVs come with built-in cameras, such as the 20 mp onboard the latest Mavic
2 Pro small
quadcopter that includes 4K video capability.
Nikon D850 camera ready for deployment from a Bergen hexacopter to support a bridge inspection
A Bergen hexacopter with Nikon D810 system onboard is landing after collecting mapping information to help locate areas of Eurasian watermilfoil in coastal Lake Huron
A Nikon D800 36 mp photo was used to help automatically assess unpaved road condition in Michigan
This 36mp Nikon D800 image of a poor-quality bridge deck was used to demonstrate automated assessment of bridge deck defects such as location and size of spalling.
This 36mp Nikon D810 helped to identify the size of a patch of invasive Eurasian watermilfoil in Lake Huron.
Thermal Sensors
We have deployed several FLIR thermal sensors, including the Tau2, Vue Pro, Vue Pro R, and Duo Pro systems, primarily for finding subsurface delaminations in concrete bridge decks. Thermal anomalies can be indicative of where concrete has begun to delaminate, creating subsurface air gaps that warm up differentially and create an identifiable pattern on the bridge deck surface.
FLIR Duo Pro and FLIR Vue Pro R sensors are being flown to identify thermal anomalies at a bridge in Michigan.
FLIR Vue Pro and Vue Pro R units mounted on a UAS to help with bridge inspection in Michigan
Analysis results show that areas of likely concrete delamination can be identified using thermal imaging collected via UAV for a demonstration bridge in Michigan.
Lidar (Light Detection and Ranging) Sensor
We have a customized lidar setup and mount able to deploy lidar sensors such as the VLP-16 system, creating 3D points clouds of bridges and ground surfaces. These can be used to find bridge spalling and ground features that would ordinarily be hard to identify.
The VLP-16 lidar mounted for deployment onboard the Bergen Quad-8 UAV
Example of a lidar point cloud collected for a Michigan bridge to help with condition assessment
Ground Penetrating Radar (GPR) Sensor and Antenna Configuration
We deploy a four-port, wideband, low frequency stepped frequency continuous wave (SFCW) radar using an AKELA vector network analyzer, with ability to transmit 256 frequencies between 500mhz and 2000 mhz. This GPS sensor system was deployed on our Bergen Quad-8 UAV to demonstrate buried object detection.
Bergen Quad-8 UAV with radar and antennas attached and ready for a GPR data collection flight
Contour plots of the 3D images generated about each buried target; coordinates are relative to the target’s ground truth position
Lightweight Portable Radiometer (LPR)
MTRI has developed a lightweight portable radiometer (LPR) system to enable spectroscopy at lower cost than traditional systems, with the ability to be deployed from UAS platforms such as our Bergen hexacopter UAS. It uses two OceanOptics STS sensors with measurements of upwelling radiance and downwelling irradiance from 350 to 1000 nm with 1.5 nm spectral resolution. The LPR has recently been deployed to create spectral profiles of submerged aquatic vegetation and harmful algal blooms.
LPR system mounted on a hexacopter UAS
Spectral profile of aquatic vegetation collected with the LPR deployed from a Bergen hexacopter UAS
Tetracam Multispectral Camera
We have deployed the Tetracam Micro-MCA6 tunable six-band multispectral camera to identify submerged aquatic vegetation species in the Great Lakes, with a focus on identifying the invasive plant Eurasian watermilfoil. We have also modified the bands to collect harmful algal bloom data and identify areas with high concentrations of dissolved organic carbon at river mouths. We can apply different polarization filters to help identify anthropogenic features in images or improve monitoring of aquatic areas.
Tetracam 6-band multispectral camera ready for deployment over a Michigan lake for identifying the extent of different species of submerged aquatic vegetation
Example of a Tetracam multispectral image displayed in color-infrared (red edge, red, and green) bands
Example of a vegetation map created using a multispectral Tetracam image where the red-edge (720nm) band helped identify dense areas of Eurasian watermilfoil near the water’s surface