Xiaomi YI 4k

[3dscanreality]

hi there,
i use sometimes a xiaomi yi 4k camera... it's a camera that is always on my bag.. it's small and very handy with a decent image quality, at least, for a action cam

however with a almost fish eye type of lens, today, i have taken 107 pictures with a nice overlap of a mural when i was processing it, the supposed plane was "broken" into two planes making around 120 degrees - "V" shape.

Is it possible that the software cant figure out my camera calibration settings?

thank you

[Roberto]

Hello,

yes, it's possible. If the cameras is not present in our calibration database, Zephyr tries to guess the internal parameters from scratch with autocalibration. Autocalibration usually work quite well, but sometimes it fails, especially with fish eye / high distortion cameras.

What you can do is:
- If you have a good dataset done with that camera, you can read the internal parameters from the camera properties (fx,fy,cx,cy,k1,k2,k3,p1,p2) and copy them in the new project wizard -] modify calibration page when starting a new project. The parameters can be also be read from an xml file.
- Try to use our camera calibration tool (lapyx) to guess those parameters. Lapyx will save an xml file, you can use that file also as a template for inserting your own parameters.
- Send us a dataset (107 pictures of a mural is fine) so that we can try to calibrate it. To calibrate it manually we have to insert a few control points. Once validated, I will be glad to insert the calibration on our online database so the next time you start a new project it will automatically recognize that camera model.

[3dscanreality]

thank you
well, if you dont mind, i'm sending you via wetransfer the dataset

really thank you for your patience

[Nedo]

Good morning, i know this is an older post, but did you got the camara calibrated?
i just bought a Yi 4k+ camera for quick scans on the go,
didnt tested it yet fully, just realized zephyr didnt have the Yi 4k+ camera in the database?
I think i'l have to go through the manual camera calibration too.

Btw. this is the camera:

[Andrea Alessi]

Hi Nedo!

we have a xiaomi in our database, so it looks like you were taking photos with a different focal lenght than what we have in database! If you can send me a dataset (eiher from lapyx or from a good reconstruction) i'll gladly add the missing calibration asap!

[Nedo]

Hi Andrea,
i just started to learn lapyx, but i have some few questions, does the monitor size matters when taking photos from the noise pattern? A bigger Monitor better?
Would it work printing the noise pattern on paper and then doing the calibration?
About the YI 4K+ cam, i will try the Photo Modus first, maybe zephyr will find the exif information then, what i did so far was only using pictures from the video mode.
I will let you know the results.

Nedo

[Andrea Alessi]

Hi Nedo,

monitor size doesn't really matter. Basically the noise pattern is used because it's very feature-rich. Printing it would also help. But basically, this is done only as a very quick and failsafe mode to show something the *we* know it's feature rich. You could easily run the same process with your own photos.

Since you're now also a happy owner of the pro, you could also simply run a dataset and export the calibration once the sparse cloud has been generated

Ah yes then! video frames have no exif information whatsoever. So you'll have to make your own calibration when using frame from videos. If you're using photos, our online calibration will be downloaded.

[Nedo]

ahh now i get it, i thought there is a hidden secret mathematical algorithmic in the noise pattern for calibrating!

[Andrea Alessi]

Hehe nah, we're very transparent in every step

[Nedo]

Hi Andrea, just wanted to inform you, after some testing i found out that the scans work if you are filming at 4000x3000@30fps, that's the same resolution when you do just photos,
zephyr know this, its in the database, i had no luck while filming at 3840x2160, but thats the interesting resolution because you can record @60fps.
The 3D modells are ok, but the textures are missing alot details compared to my Nikon DSLR, so i think i will sell the camera and wait for the 8K cam

greetings Nedo

[Andrea Alessi]

Hey Nedo,

thank you! If you have a dataset you can share with us, i'll see what can be done about it

[Nedo]

Hi Andrea, i will shot a a new set with the 3840x2160 setup, and extract the pics for you.
Until then, check out here the result with the 4000x3000 setup:

[Nedo]

Andrea, can i mix cameras in 3DF Zephyr?
Lets say i use the YI 4K+ for the whole model,
and then use my Nikon for only a few parts where i need hires Textures?

[Roberto]

Yes, you can mix different cameras without problems. You can also select a subset of images to use for texturing. Sometimes it's better to select just a subset at a fixed distance or with known higher quality.