The Most Boring Model on the Internet
Its never a good idea to test software capabilities when the pressure is on to deliver a job. The manual may well claim everything works out of the box but its a high risk strategy.
Which is how we came to find ourselves standing in a field flying a drone. There is a little job coming up that will need an aerial platform and Grahame Knott of Deeper Dorset was kind enough to loan a drone.
The most boring 3D model in the history of 3D models. A flat grassy field. the only distraction of note is my lovely wife sitting on the grass.
The job in question demands some very accurate landing. The area for the drone to land is tiny and there will be no second chances. But as we know photogrammetry to be addictive I couldn’t help myself. So I scanned the field using the onboard GoPro Hero 3 Black.
Rolling Shutters
The Hero 3 Black has a design feature called a rolling shutter. You can read more about it here but the main issues rolling shutter caused with previous versions of Photoscan Pro were generating gently curving models. Over short distances no one will notice but the greater the distance then the curve becomes apparent.
My garden serving as a GoPro test bed. The model gently curves in both axis.
Thing is, those GoPro cameras are really useful tools and Grahame and I are sending a few to the depths of the English Channel soon. Having a underwater camera that will capture stills for photogrammetry would be a huge benefit to the project. And if we lose it the replacement won’t break the bank – unlike a housed DSLR.
Photoscan 1.4
Its been out a while now but Photoscan 1.4 now allows us to fix the rolling shutter issue. Tucked away on the Camera Calibration dialog is a new tick box called Rolling Shutter Compensation.
Enable rolling shutter compensation – the tick box to solve GoPro Hero 3 alignment issues.
With rolling shutter compensation enabled the camera alignment delivers the results as intended.
Summary
The older GoPros have their uses. Deeper Dorset team just bought a pile of them and whilst they won’t replace the DSLR for photogrammetry they will have definitely have their uses.
If you have gotten this far its only fair you have the chance to take a peek at the most boring 3D model in the history of 3D models. Enjoy!