High Res Orthomosaics of Reflective Buildings Basically Impossible?

I want to create a high resolution orthomosaic image of the side of a building that one side is about 100 feet wide by 250 feet tall. There are some very small fasteners on the sides of the building that are an inch wide in different places that I want to see the condition of in addition to the condition of the window molding (which can be farther away). It’s almost black building that is virtually all glass except for the windows panes so it is almost like a large mirror.

What I found was to get the resolution I needed I had to fly about 20-25 feet from the side of the building. There’s no way any of the stitching programs worked because the windows are reflecting like a mirror buildings and scenery from far away. So it is almost the same as if I was taking photos of a building a half mile away and moving the drive position moves about 10 feet vertically or horizontally between shots.

The resolution I need I calculated is 0.12cm/pixel. Yep. I need about 20 pixels per inch. So I think the only way to do this project is to film in 4k and just do video then just pause the video and zoom as necessary. The problem is when you are filming that close, when the edges of the building aren’t visible and all the window panes look identical and the frame holds about 5 windowpanes and the building is 25 windowpanes wide, you can easily lose track of which windowpane you’re looking at! I think the only way you could pull off a super high-res orthomosaic of a mirrored building would be to place different color control points on the side of the building which isn’t feasible in this case.

How did you advanced on this issue.?
We have been doing facade inspection, and build a mosaic of tha facade still an issue, even it is not mirrows made.

We switched to make inspection through 4K video. counting manualy the number of floors by counting windows or pannels.

It still hard work.

Kind Regards
Mauro Abram

It sounds like this is going to be a very special piece of modeling. The program should be able to model that with no problem as long as there is some kind of frame to be seen. A completely cloudy day would be the best. It’s similar to trying to model a body of water. Never at a perpendicular position to the face you want to shoot about 45 degrees in. This needs to be done in at least two flights. Unfortunately you cannot do it in DroneDeploy. One flight needs to capture several panels at the same time. The next one can be much closer at the resolution that you need. The wider frame flight will help it stitch everything together.

What is your recomendation in terms of software to build 3D model and proceed with inspection routine
I will try and give a feedback!

Many tks!!

I would recommend trying DroneDeploy and Agisoft Photoscan. Both are available for free trials with partial (DD) or full functionality (Photoscan). If you try Photoscan, please be sure to push the Help button, select Contents and read the entire users manual as it has many tips for successfully processing of your Photos into a 3D model.


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DroneDeploy’s structure mode is almost capable of doing it, but it always makes you run a Nadir flight on top. That is not always needed so it is a waste of time and battery. Particularly when you are doing two or three flights. The other issue is that it is always looking at one point in the center of the defined plan so looks at very near-perpendicular angles in the middle and very acute angles on the ends. There use to be a 3D mode in which you had the option to not use nadir and the gimbal pitch was configurable, but that went away.
I always recommend Litchi, but you have to pay $23 for it. It allows you to create many more flight modes that are not practical for DroneDeploy to provide and quite honestly we probably don’t want them to because it would make the interface a mess like AutoPilot. With Litchi you can define each waypoint individually for all aspects of altitude, pitch and yaw if you like or you can batch-edit points. They also provide a PC browser interface for planning. I like to setup the mass of my mission there and fine tune it on my iPad.