WIP: Building roof type classification

[arno]

Hi all,

I have started working on a new challenge after the machine learning feature detection. This time the aim is to be able to classify the roof types of buildings based on the imagery of the building. I have already found a nice scientific article that describes an approach for this. So I want to see if I can get that working in scenProc. I have no idea yet how long it will take to get this really working, but I will use this thread to keep you up to date about the progress.

 

[arno]

The basic approach of the algorithm is to extract the roof images and then all align them horizontally and resize them to the same size. That allows characteristics of them to be compared and different types to be classified. For now I focus on the 4 vertex building footprints only, as the more complex ones need to be split into rectangles before feeding them to the algorithm.

The first challenge is that the building footprints and the imagery I have do not align very well for many of the buildings (see the image below). That means the extracted roof image has a lot of noise in it and that makes it hard to collect good data to train the algorithm with.

I might have a look at detecting the building footprints first, so that they align better with the imagery. But on the other hand that can be a complex task as well.

 

[Clutch Cargo]

Now there's a nice little challenge! So is the idea down the road by detecting the roof types you might be able to create "non-square" autogen buildings?

 

[arno]

Autogen buildings are always rectangular, but with the 3D buildings that scenproc can make you can work around this. I tested that on a statewide scale already. But my dream is to have the correct roof type on each building, now I assign them randomly.

 

[=Hollywood=]

That is awesome Arno!

Hey Arno along similar lines have you seen this?

 

[arno]

I guess I should check that video for some inspiration. The current approach for the vegetation does not seem to work that well for buildings.

 

[arno]

I had a look at the video by now, unfortunately it does not provide that much detail (those are in the model that is just downloaded). But being able to do something like that in scenProc would be cool. However I have no idea what kind of techniques they exactly used, they just call it deep learning. I'll see if I can find some scientific articles on this.

 

[arno]

I haven't given up on this idea yet. To be able to classify the roof types correctly, I will first have to have building footprints that match well with the imagery. So I am looking at adding the footprint detection to scenProc. Will be a nice journey that will allow me to learn more about machine learning again. I'll keep you posted about the progress.