xiaomi yi barrel distortion correction

fjunk

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hello,

I got a new xiaomi yi camera. It is nice. I had previously a sjcam 5000. I was used to correct barrel using mogrify (magick)
mogrify -distort barrel "0 0 -0.3" *.JPG
see previous thread: https://dashcamtalk.com/forum/threa...nous-shooting-and-some-other-questions.10662/

optical is slightly different from the scjcam. The correction is not as so good. Does someone has acceptable values to apply.

Note: i am using a linux based portable (ubuntu). So i would prefer open-source solution.

Regard.
 
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This camera has implemented warping function in itself, if you use my C&C, you can do "warp_enable" to autocorrect images for fisheye, i don't know if official apps have this implemented.
 
Thanks for your answer.

I know that the camera has a built in mechanism to correct the distortion. This feature is available with the official application. It is not really what i am looking for.

I am looking to get parameters to correct photo or video as post-processing. I like to get 'raw' data and then be able to process it. I would like to get similar information as for:
https://gist.github.com/KonradIT/ee685aee15ba1c3c44b4

by the way, does anyone know if it is possible to tune the white balence or exposure?

regards
 
well, you can only choose metering mode (spot/center/average), white ballance is a no-go unless you capture RAW image. But the output from it is far worse than from jpg as there is no proper decoder yet.

And for the fisheye - you'll have to do some experiments with "calibrated" picture sheet, you can find those freely on google.
 
The lens rectification option is a little useless in my opinion. And its hard to turn it on and off depending on circumstances. A proper post processing solution would be much better indeed.
Lets hope someone gives the proper command line for the Yi Cameras lens. Mogrify works good.
 
Hello, i played a little with convert/mogrify (image magick).

I did a script to change values of the barrel transformation command:
convert YDXJ0292_01.jpg -virtual-pixel black -distort Barrel "0 0 -0.3$i" result/ydxj0292_convert_03_$i.jpg

Here are some results:
https://www.dropbox.com/sh/jygskae5g4ymz6a/AADGNl45RxBlszWmVYjU1jKna?dl=0

Folder original contains original pictures. YDXJ0291 uses XI XIAMO lens correction, YDXJ0292 no correction
folder barrel contains a set of picture result of barrel correction with parameters from "0 0 -0.30" to "0 0 -0.35". From my point of view, best result is "0 0 -0.33".
folder scaling_1.5 plays with the scaling of the picture. It uses values from "0 0 -0.35 1.5" to "0 0 -0.39 1.5". here, best resutl is "0 0 -0.38 1.5".

This is really not an official value/setting. I am pretty sure that someone may define better values. It is interessting to notice that the xiaomi yi lens correction crops really a lot the picture.

I didn't try to find out values for video. If someone has already settings (using kdenlive openshot), it would be nice to share it.

Regards.
 
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