Found in some bokhen folder from DJI a infrared photo, looks like they use it to determinate depth.

It's not an infrared photo, it's a depth map.

Yes meaby you are right but it's in jpg format so it's a photo Good to know they are implementing the technology not only to one thing like gesture control. I bet this can be used I many different things.

was this on the sd card? its probably the depth map for touch to focus to work after the image has been captured

Was in my phone , in one of the 10+ folders that DJI go 4 made.

yup, that will be the depth image for the app to allow touch to focus to work if it was on your phone.
You could use it on the original image if you wanted to be a bit more creative than just using the app.Use it as an alpha map with the lens blur effect in photoshop

https://www.psdbox.com/tutorials ... stic-depth-of-field

Thinking about it you could even make a 3D image using the depth map and the original image.
This video would get you started