Inspections consist of a set of overlapping photographs of an entire roof or structure, enabling the client to get a clear view of a roof’s condition. These images can include chimneys, valleys, and guttering, and are available to the client anytime from the comfort of their office.
Images are shot in high resolution using a lightweight camera drone, delivering 48MP / 4K images with digital zoom capabilities for close inspections.
Example of a roof inspection showing valleys, gulleys, flat roof section & leading
Example of a chimney inspection showing inaccessible areas of roof & chimney
Examples of Inspection Images
A survey consists of a similar set of overlapping images but in a more accurate Photogrammetric form. These are far more precise in terms of positioning — centimetre rather than just metre accuracy of general inspection images. They can be used for various measurements and in industry-specific applications like CAD (Computer Aided Design) or BIM (Building Information Modelling).
https://www.thamesvalleydrones.co.uk/survey-grade-drone-roof-building-land-surveys
Photogrammetry is a technique that uses multiple images to produce a point cloud of data — images and their precise location (cm accuracy) in relation to each other, the site/location, and its position on the Earth’s surface.
These images require a specialist drone with RTK (Real Time Kinematic) or PPK (Post-Processing Kinematic). These GPS correction technologies provide precise real-time GPS data for processing in survey-grade photogrammetry software.
Photogrammetry and geo-referenced data
Essentially, photogrammetry takes overlapping images and location data and stitches them together to create a true digital 3D model of the physical world — a digital twin. This is achieved by cross-referencing geo-referenced drone images and base station signals, using a recognized earth coordinate system like WCS, UCS, or EPSG.
Georeferenced data is data associated with a specific location on Earth. This process, called georeferencing, allows users to determine the exact location of any point in the data.
This photogrammetric process enables the production of various useful outputs.
Point Cloud
The first part of this photogrammetry process is to generate a point cloud from the data (images & position). The point cloud can be processed into a fully textured three-dimensional object (model).
The point cloud and its models can then be used to take measurements, calculate volumes, produce geo-referenced data for import into CAD and other architectural and construction applications, generate 2D or 3D orthomosaics and 3D models of an object or surface. A 3D orthomosaic is essentially a digital twin of a real earth object.
Orthomosaics are images that are geometrically corrected for perspective, lens distortion, and camera angle, to create a perfectly straight-down view of all objects in the frame—similar to Google Earth but at much higher resolution.
Example of a survey grid (to collect the data):
https://www.thamesvalleydrones.co.uk/barclaycard-grids
Example of point cloud data:
https://www.thamesvalleydrones.co.uk/barclaycard-point-cloud
Example of an orthomosaic:
https://www.thamesvalleydrones.co.uk/barclaycard-orthomosaic
Example of a 3D model (roof only):
https://sketchfab.com/3d-models/project-65884-iss3d-1c335792245b44d983adec514fd48063
Example of a set of inspection images:
https://www.thamesvalleydrones.co.uk/barclaycard-survey-images
Example inspection image:
https://www.thamesvalleydrones.co.uk/barclaycard-sample
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