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OpenDroneMap – Simple Images into 3D

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Re: OpenDroneMap – Simple Images into 3D

#31

Post by bronco21016 »

jcvhaarst wrote: post #5

What kind of image quality would one need to get something useful out of this. Useful : Create a 3d model of a house with surrounding trees, so I can see the effect of those trees on a planned solar installation. Or create a 3d model of a garden to see where the sun and shadow are over the course of the year.

I love the idea of your proposed application. However, I don’t see it as a problem needing solving. It’s fairly easy to survey a solar installation and potential shadows using basic trigonometry and sun charts. I would imagine many solar installers can do this in under an hour.

I was running some experiments with Drone Deploy and my DJI Mavic to document road damage and flooding in my neighborhood because the city has neglected to maintain our storm water infrastructure. Perhaps I wasn’t using high enough overlap but I found I could not get quality orthophotos at the desired resolution because of too many trees. Using a higher altitude (lower resolution) would yield quality orthophotos but then the details I wanted to see like potholes and standing water were not clear enough. My point is I think these tools can work really well when the conditions are right, as evidenced by all of the high quality samples and demos, but there are still a lot of situations where you’re just not going to get very high quality due to conditions of the subject area.

Re: OpenDroneMap – Simple Images into 3D

#32

Post by punnerud »

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…

OpenDroneMap use a text file where you specify image name and pixels with their corresponding GPS coordinates for those pixels. Pitch, yaw, gimbal direction can probably help you with optimizing those algorithm. I am thinking of using OpenCV for image recognition of a large “chess board”, from there it should be easy to get both the GPS-coordinates and pixels in the images seeing this calibration board.

Re: OpenDroneMap – Simple Images into 3D

#33

Post by mohaine »

fsloth wrote: post #7

It would be nice to know how this compares with other open source and commercial photogrammetric offerings. Free: - AliceVision https://alicevision.github.io/ - Colmap https://colmap.github.io/ - etc. Commercial: - Agisoft Metashape (formerly Photoscan) https://www.agisoft.com/ - Zephyr 3D https://www.3dflow.net/3df-zephyr-pro-3d-models-from-photos/ - Drone deploy https://www.dronedeploy.com/ - etc etc etc See also:…

We are using ODM for generating orthomosaic photos and it produced better results than the commercial offerings we have seen (In some cases MUCH better). Note this did require us to tweak the settings some but overall it was pretty easy process.

Things of Note: 1) ODM didn't quite scale as well to very large number of photos. (I think this may have been fixed now). 2) Our use case was pretty brutal. ~1 cm resolution photos of a mostly uniform row crop fields. Some of the other tools were really bad at not rotating the rows 90 deg in parts of the field. 3) I was in on the POC and selection process but not the production runs so I'm not sure how things have changed over the last year. 4) Some of the comparisons where with different photos (Looking at a custom full path) 5) We didn't look at 3d much at all, but it was pretty cool to be able to see 3d tractor tire marks across and freshly planted field. The 3d quality would really fall off at the edges when there was less overlap. I think it was only good in relative hight as well but our tests were very flat.

Re: OpenDroneMap – Simple Images into 3D

#34

Post by mohaine »

truesy wrote: post #30

Used this pretty extensively, and followed their dev branches. FWIW if you want quality results the best option is Agisoft, on a GPU machine w/ some custom python to automate.

FWIW, ODM was slightly better quality than Photoscan in our tests. We only tested orthomosaics but ODM had less error to our ground control points (note we didn't feed the givens into these tests) and less aberrations.

Re: OpenDroneMap – Simple Images into 3D

#35

Post by mohaine »

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…

All ODM needs is a centroid Lat/Lon from the EXIF tags on each photo. You can optionally add a text file that gives a pixel an exact Lat/Lon. From this it matches features from the photos to calculate the exact pitch, yaw, direction. I think you can specify those in the EXIF but it is really hard (i.e. expensive) to get these to high enough quality to render the final image.

In our case the high quality gimbals where more than our drones. (~$15k each)

Re: OpenDroneMap – Simple Images into 3D

#36

Post by andrey-g »

mavhc wrote: post #22
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

Not that high -- 4800 x 2848 is the max resolution.

Re: OpenDroneMap – Simple Images into 3D

#37

Post by punnerud »

Fission wrote: post #27
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 t…

You can solve this edge case using a light source, with a method called “structured light”: https://en.m.wikipedia.org/wiki/Structured-light_3D_scanner

Re: OpenDroneMap – Simple Images into 3D

#38

Post by Leherenn »

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…

Depends on the drones, but professional photogrammetry drones certainly do. You often have position (latitude, longitude and altitude in WGS-84), attitude (yaw, pitch, roll) which already contains the gimbal orientation (e.g. the drone applies the lever arm to go from the IMU position to the camera optical center and output those) along with their covariances (accuracy) as well as timestamping. If the camera has a rolling shutter, you might even have imu data (i.e. accelerations) to correct distortions. Another important data for the reconstruction is the focal length.

Ultimately, it is the job of the reconstruction software to use those data. Usually, they use them to initialise the process, and use the covariances as constraints, then they run their optimiser based on that. If your accuracies were too tight, the reconstruction will often fail as they trust you on the accuracies. However, the better/more accurate the data (e.g. RTK data), the faster/easier it is for the software to do its job.

Re: OpenDroneMap – Simple Images into 3D

#40

Post by archanox »

fsloth wrote: post #7

It would be nice to know how this compares with other open source and commercial photogrammetric offerings. Free: - AliceVision https://alicevision.github.io/ - Colmap https://colmap.github.io/ - etc. Commercial: - Agisoft Metashape (formerly Photoscan) https://www.agisoft.com/ - Zephyr 3D https://www.3dflow.net/3df-zephyr-pro-3d-models-from-photos/ - Drone deploy https://www.dronedeploy.com/ - etc etc etc See also:…

I was thinking the same thing about OpenAerialMap https://openaerialmap.org/
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