3 Replies Latest reply on Nov 6, 2018 8:35 AM by MartyG

    d435 - visible light filter

    fubs

      I am using the d435 in various locations at night time for stereoscopic IR footage, which sometimes include e.g. halogen lamp sources, which flicker and hence mess with my motion detection algorithms.

      It would seem that a visible light filter would do the trick (which i assumed would be inbuilt but isn't). Does anyone have a suggestion for an off the shelf visible light filtering solution for this camera?

        • 1. Re: d435 - visible light filter
          MartyG

          The current 5.10.6 firmware update added a fix for flickering when auto-exposure is on, which may help to stabilize your image.  The disruptive effects of gas-based lights such as fluorescent may also be reduced by running the stream at an FPS that is close to the frequency that the light is operating at.  In the case of fluorescent lights, this has been 30 FPS for some people and 60 FPS for others, depending on the particular lights in their location.

           

          If you are using IR dot pattern projection to add texture to a scene for the purposes of improving depth analysis, an external LED based IR projector may give better results than the laser-based IR projector inside the camera, especially for reducing laser speckle.

           

          In recent discussions about IR filtering, a few users have sought to construct their own filter covers to replace the transparent material on the front of the camera casings.  It is possible to buy non-reflective acrylic / perspex from companies that will cut it to size for you.  An alternative is to place a micro-thin IR film over the imager lens.

           

          The links below to these recent discussions may be useful to you.

           

          Lens specification for D400/D435 cameras · Issue #2566 · IntelRealSense/librealsense · GitHub

           

          Which transparent material will generate the least interference with the D435?

          • 2. Re: d435 - visible light filter
            fubs

            The firmware update did the trick indeed. I was playing with polyester filters but then would have had to make an attraption to bend them to avoid newton rings (or replace the flat surface), so this firmware update is much welcomed news.

            • 3. Re: d435 - visible light filter
              MartyG

              Great news that the firmware update was a solution for you!