We recently worked with a company who purchased a True View 410 3D Imaging System (3DIS) along with a DJI M600 drone and assorted accessories. This customer wanted to also purchase a camera for those times when they wanted to use photogrammetry rather than colorized LIDAR. An example of a photogrammetric use case might be dense texture modeling of a build facade. This request made us realize that some prospective customers are not aware that the True View 410 is effectively 3 mapping sensors in one:
The directions to the scanner that tell it how to operate are contained in a file on the USB Memory Stick (UMS) that is plugged into the True View 410 prior to power on. The True View 410 reads this Core Configuration File (CCF) on bootup. You can tell the system which mode to function in using parameters in this file.
Before discussing these operational modes, lets first consider the sensor complement. The True View 410 includes dual photogrammetric cameras canted at 25 degrees off-vertical. This gives a wide 120 degree cross-track field of view. These cameras are specifically designed for photogrammetric mapping by virtue of their fixed focus lens, mechanical shutter and electronic mid-exposure pulse (MEP, a signal that allows time synchronization of the images with the GNSS). The LIDAR sensor is a 430,000 pulse per second Quanergy M8 Ultra that has been calibrated to mapping standards. Finally, all this is positioned and synchronized using an Applanix (a Trimble company) APX-15, a UAV survey grade Positioning and Orientation System (POS).
The 3D Imaging Sensor (3DIS) mode is the default for the True View 410. This means that it will simultaneously collect imagery and laser scan (LIDAR) data. The included workflow processing software, True View Evo, will automatically recognize 3DIS mode and lead you through post-processing to a stunning colorized, 3D point cloud (Figure 1).
LIDAR Mode collects LIDAR data with the cameras deactivated. All drone LIDAR systems except the GeoCue True View sensors are of this type. If you can get a camera, it is an extra cost add-in that is not tightly integrated in post-processing. If you operate in LIDAR Only mode, True View Evo post-processing will produce a high accuracy 3D point cloud but it will not have RGB colorized points like the 3DIS mode. Why would you run in this mode? It is a real stretch of the imagination but perhaps you are flying at night and thus camera imaging would not be possible.
Finally, there is the photogrammetry only mode. To enter this mode, you instruct the True View 410 (via its CCF file) to activate only the cameras. This will give you a dual, oblique camera photogrammetry system. The POS is fully active in this mode and True View Evo will encode the images with their precise location and orientation at the time of exposure. We include workflow paths from True View Evo to popular photogrammetry software such as Metashape and Pix4D.
So the message here is that an investment in the True View 410 gets you all three sensor modes. Yet another reason the True View 410 has, by far, the shortest Return on Investment (ROI) of any general purpose drone LIDAR system.