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OpenDroneMap – Simple Images into 3D

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Re: OpenDroneMap – Simple Images into 3D

#21

Post by linsomniac »

This morning I was watching a "video editing" youtube video where he made a 3D terrain object to load into Davinci Resolve (commercial but free for personal use), and track to the palm of his hand so it looked like the terrain was floating above his palm.

He used http://terrain.party/ to get height information as an image (lighter colors are high, darker are low), then a script scrape together images from Google Maps, which he transformed using the height information.

At that point he was using a GUI to view the resulting 3D object and manipulate the camera and lighting. Blew my mind.

I followed it part of the way, but got stuck with getting the google images. He was doing a valley close to an object recognizable from space close to the coast, I was trying to find the cabin we stayed at last weekend in rural Colorado.

Pretty mindblowing what you can do with free video editing software today.

https://www.youtube.com/watch?v=qP6wVajeI_M

Re: OpenDroneMap – Simple Images into 3D

#22

Post by mavhc »

linsomniac wrote: post #21

This morning I was watching a "video editing" youtube video where he made a 3D terrain object to load into Davinci Resolve (commercial but free for personal use), and track to the palm of his hand so it looked like the terrain was floating above his palm. He used http://terrain.party/ to get height information as an image (lighter colors are high, darker are low), then a script scrape together images from Google Maps…

Google Earth Pro is now free, and has an export high res image function

Re: OpenDroneMap – Simple Images into 3D

#23

Post by [deleted] »

jcims wrote: post #4

Are there editors that allow you to manipulate point clouds or ‘digital surface models’? (Not sure what those are) I’d like to use something like this to digitize my property and model changes to it (building, landscaping, etc).

[deleted]

Re: OpenDroneMap – Simple Images into 3D

#24

Post by yeldarb »

ViktorV wrote: post #15
yeldarb wrote: post #13

I assume this uses GPS data to help with stitching the photos together. Do drones capture orientation data beyond GPS position (for example, pitch, yaw, gimbal direction)? I have tried adding motion graphics to some of my drone videos in After Effects but as far as I can tell it discards all of the metadata and infers the camera position based solely on the video frames. This is really slow and imprecise; I’ve been w…

I don't think it uses GPS for that. You can match two partially overlapping images. From the movement of the feature points in the overlapping areas you can calculate your camera orientation, and thus the 3d point cloud of feature points ( or something close to this ). I think it is called structure from movement, the readme links a paper, maybe it's worth reading for you.

Interesting, is there a technical reason for not using that extra data to help with the process?

For example, another commenter mentioned

> Some materials don't really contain any surface details that the algorithms could use to attach feature points to, so they will be blank. Large white walls and large windows are especially difficult.

Seems like you might be able to position some of these with orientation data from the camera.

Re: OpenDroneMap – Simple Images into 3D

#25

Post by gloflo »

ViktorV wrote: post #15
yeldarb wrote: post #13

I assume this uses GPS data to help with stitching the photos together. Do drones capture orientation data beyond GPS position (for example, pitch, yaw, gimbal direction)? I have tried adding motion graphics to some of my drone videos in After Effects but as far as I can tell it discards all of the metadata and infers the camera position based solely on the video frames. This is really slow and imprecise; I’ve been w…

I don't think it uses GPS for that. You can match two partially overlapping images. From the movement of the feature points in the overlapping areas you can calculate your camera orientation, and thus the 3d point cloud of feature points ( or something close to this ). I think it is called structure from movement, the readme links a paper, maybe it's worth reading for you.

Would a high-quality pre-registration via precise coordinates and orientation yield better (and faster) results though? If the algorithm did not have to guess the camera parameters I would imagine a benefit.

Re: OpenDroneMap – Simple Images into 3D

#27

Post by Fission »

dwiel wrote: post #26

Does anyone have any experience with the ZED camera? They claim they can generate 3d maps down to 1cm resolution without LIDAR using these kinds of methods.

The ZED camera works by using two high-resolution RGB camera, finding matching points between the two, and using that to calculate depth. Because they are using high-resolution RGB cameras, they can generate very high resolution depth maps. However, this is also their main drawback; with just RGB images, depth map calculation will fail on texture-poor surfaces, such as plain white walls, because it's very difficult to match points.

They are fundamentally performing photogrammetry with two cameras at a fixed distance.

Re: OpenDroneMap – Simple Images into 3D

#28

Post by Fission »

yeldarb wrote: post #24
ViktorV wrote: post #15

Earlier quoted context omitted.

I don't think it uses GPS for that. You can match two partially overlapping images. From the movement of the feature points in the overlapping areas you can calculate your camera orientation, and thus the 3d point cloud of feature points ( or something close to this ). I think it is called structure from movement, the readme links a paper, maybe it's worth reading for you.

Interesting, is there a technical reason for not using that extra data to help with the process? For example, another commenter mentioned > Some materials don't really contain any surface details that the algorithms could use to attach feature points to, so they will be blank. Large white walls and large windows are especially difficult. Seems like you might be able to position some of these with orientation data fro…

The GPS data is probably being used as a prior. The GPS metadata is accurate but imprecise, while SFM more precise. GPS is likely used for pose initialization, while SFM is then used to refine the pose.

Re: OpenDroneMap – Simple Images into 3D

#29

Post by Fission »

gloflo wrote: post #25
ViktorV wrote: post #15

Earlier quoted context omitted.

I don't think it uses GPS for that. You can match two partially overlapping images. From the movement of the feature points in the overlapping areas you can calculate your camera orientation, and thus the 3d point cloud of feature points ( or something close to this ). I think it is called structure from movement, the readme links a paper, maybe it's worth reading for you.

Would a high-quality pre-registration via precise coordinates and orientation yield better (and faster) results though? If the algorithm did not have to guess the camera parameters I would imagine a benefit.

In practice, there are a couple of ways to handle this. In one case, EXIF data gives you a lot of information (sensor size, camera/drone make, etc.) that you can extract very good camera intrinsics from. This information can also be fed into big EXIF databases, from which you can obtain pretty accurate camera parameters.

Additionally, camera intrinsic calibration is a relatively solved problem, especially if you know that every single camera has the same intrinsics.

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