external IR illuminators

[timprepscius]

General, Probably a smidgeon off-topic

Issue Description

Has the intel team done any testing integrating external IR illuminators? (Or anybody else for that matter)

Are there any products on the market which are known to work?

Basically, it would be great if there were a IR VCSEL product which could illuminate an entire scene (not pattern), and take timings from the RS.

[agrunnet]

It sounds like you just want to illuminate with IR light (no pattern). Yes that works. You can use any IR light sources. Doesn’t need to be VCSEL. The D4xx will see the light and be able to give depth as well.

If you want a pattern projector there are a few on the market. Please read our white paper on “best known methods” which includes a section on external projectors.

[timprepscius]

Do you have a link to this paper?

[AntoineWefit]

Might be this one :
https://www.intel.com/content/dam/support/us/en/documents/emerging-technologies/intel-realsense-technology/BKMs_Tuning_RealSense_D4xx_Cam.pdf

[timprepscius]

Thanks, I read it.

Does anyone have any experience with existing products on the market for illumination?

I need an IR illuminator which originates from the smallest point, and has the smallest physical footprint. It would be best if I could place it in front of the IR pattern projector of the D435, without obscuring the two stereo imagers. Second best would be to place it directly above the stereo imager with the least amount of distance between it and the stereo imager. (So in other words the LED illuminators built for security cameras don't work)

I have tried various LED based projectors, and they are not strong enough. They would be strong enough if the D435 could take two pictures per picture, one with the illuminator ON and one with it OFF, so as to filter out the background, but this is of course not possible. (Would be a nice feature)

Has anyone used a VCSEL based illuminator?

Or built one? Does anyone have any reference material on building one?

[agrunnet]

You want a uniform flood illumination. And you have tried 3W LEDs and they are not powerful enough? What range do you need? Indoor outdoor? Day or night?
Generally you can do 4 things to increase illumination.

1. Use more powerful LED or bank of LEDs. Basically throw power at it. But it will increase in size even though you can buy quite powerful ones.
2. Add an IR bandpass or highpass filter to the front of the left and right imager. This will increase the SNR quite a bit. Especially indoors. It will essentially be like operating the unit in the dark.
3. Trigger and burst the LEDs to camera frame. This works well for the d435 which is global shutter. A trigger signal can come off the camera and you can strobe an external light source with it. (Obviously the signal is too weak to drive the LED but can be used to trigger the LED)
4. Turn the LED on and off and subtract images. You can test this first by your self and see if it works. We are looking into adding that feature on a per frame basis.

[timprepscius]

Yes.

I'm wondering specifically about VCSELs. I have researched available LEDs. I am using one, along with a bandpass. It is barely powerful enough. I need something that can be used outside.

The laser within the D435 is powerful enough, however it is a pattern.
I need the same power, but flood.

Does anyone have any experience building VCSEL flood illumination?

[RealSense-Customer-Engineering]

[Realsense Customer Engineering Team Comment]
Hi @timprepscius,

Did you already check any VSCEL vendor to create the flood illuminator for your usage?

[timprepscius]

Yes, but if you have any suggestions, I would gladly take them.

…

On Sun, Sep 16, 2018 at 11:09 PM RealSense Customer Engineering < ***@***.***> wrote: [Realsense Customer Engineering Team Comment] Hi @timprepscius <https://github.com/timprepscius>, Did you already check any VSCEL vendor to create the flood illuminator for your usage? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#2000 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADML5k9PIskjE0IWU-b4_qy-6hxO0G54ks5ubxJ1gaJpZM4VBwNg> .

[logindiamant]

Dear collegues!

We plan to connect external IR projector with RealSense D435, eg
https://www.flir.eu/products/cli-30
https://www.flir.eu/products/cli-650/

Please tell us more about your experience connecting external projectors to a camera

[agrunnet]

You can illuminate the scene with those projectors. They do not provide any texture though (ex. No dots) so they will simply have the effect of turning on more uniform illumination.

[logindiamant]

Thanks,

Moreover, it is not easy to bue this CLI with export limitations...
Does anyone know other manufacturers VCSELs CLI? And lens/pattern/textures?