Comment by laen | Hacker News Reader

Comment by laen | Hacker News Reader

I've been trying to get my organization to use ODM, but finding it difficult. The problem is analogous to the issues that Gimp has to Photoshop or Linux to Windows -- ease of use. Additionally, even if you properly configure the software the quality still is not comparable to the big proprietary players in the photogrammetry field: Bentley Systems; Pix4D; Drone Deploy.

A major reason for the quality issues is that the major drone manufacturers work directly with the proprietary photogrammetry software providers in the field to optimize the algorithms to their drones. These drone manufacturers then promote these proprietary solutions. This puts ODM at a disadvantage as there is no short-term financial incentive for manufacturers to promote ODM.

Like other fields, the proprietary photogrammetry industry is increasing moving to implementing their solutions exclusively in the cloud. This is forcing folks to give up their data and building a data moat - a problem for my organization.

I hope ODM keeps developing and becomes as ubiquitous as linux. Its quality is getting close for my organization to consider its implementation. Keep up the great work!

Are you aware of solutions like Alicevision/Meshroom (MPLv2)?

https://alicevision.org/

Thanks for championing ODM! :) It's true that proprietary systems have had a lead in development for a long time, but especially of late the software has gotten really good. If you haven't tried the software in a while, I'd recommend updating and giving it another try.

The quality issue is an interesting one; I remember having a discussion with a client that was considering transitioning away from Bentley's ContextCapture (CC) and they mentioned that CC was generating much denser point clouds compared to ODM. CC tends to generate very good looking point cloud models, except its algorithms extract points from a mesh interpolation approach, so sometimes you end up with points where geometrically there shouldn't be any. Sure they look good, but is that "good" quality?

> A major reason for the quality issues is that the major drone manufacturers work directly with the proprietary photogrammetry software providers in the field to optimize the algorithms to their drones.

Would you care to elaborate? My belief is that all the photogrammetry engine wants is that the drone manufacturer does as few processing as possible on the images, in order to not alter the geometry. I don't see what kind of algorithms coming from the drone manufacturer would help, and therefore I don't see how that's a problem for ODM.

Direct knowledge of the lens distortion model and complete control of the image generation, with perfect knowledge and use of the associated metadata tags, can certainly give an engine a leg up in some cases. One example I can think of is the Parrot Sequoia which is a camera that works OK-ish in ODM, but works flawlessly with Pix4D (which is owned by Parrot).

But none of that is private data, right? It feels like "tuning". Surely one could characterise Sequoia to improve the camera model, and I doubt they encrypt the exif data, do they? Also Sequoia is a bit of a special example here, that most likely has been carefully tuned by Pix4D. But DJI most probably does nothing for Pix4D that ODM couldn't access.

Not criticising ODM (I love OpenSfM and ODM), on the contrary: I feel like those are not fundamental limitations of ODM, and one could put the work of improving support for specific cameras without the need for proprietary information available only to Parrot employees.

Or am I missing something?

EXIF data is not encrypted, but often times is not documented (or documented well). DJI has many differences between models (even between firmware versions). They also sell DJI Terra, which is their own photogrammetry solution.

The point being that you are correct, these are not limitations of ODM, but in some cases it does give vendors a head start (a leg up) in implementing good support for certain cameras, especially multispectral cameras like the Sequoia.

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