IR Image with auto ir exposure is dimmer than manual on D415 cameras

• MartyG

  • January 27, 2022 23:15

  Hi Karthikeyan Yuvraj  I am reminded of a phenomenon demonstrated in the link below where the exposure and gain of the camera would drop to minimum level if auto-exposure was enabled and the camera was directly facing sunlight and therefore darken the infrared image. 

  https://github.com/IntelRealSense/librealsense/issues/4928

  In such circumstances, facing the camera away from the sunlight or holding a hand over the camera lenses for several seconds should result in auto-exposure correcting the image.

   

  Is your D415 in a location where it might be directly observing sunlight or a similar strong light source head-on, please?

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• Karthikeyan Yuvraj

  • January 31, 2022 16:21

  Hello MartyG,
  Thanks a lot for your reply. The camera is in an indoor location (and no sunlight), but the camera is facing straight ahead at the whiteboard (which is bright), maybe this is causing it?. Also, based on the thread you shared, can a firmware update fix this?.

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• MartyX Grover

  • January 31, 2022 17:22
  • Edited

  If the whiteboard had a reflective surface and light was being projected onto it then I can see how it could create a glare from the reflection that could have a negative impact on image quality.  

   

  There was a past case (in the link below) where a camera was located indoors in an office and tests with strong light projections such as an external flash and a laser pointer caused the camera to react as though it had faced the sun.

  https://github.com/IntelRealSense/librealsense/issues/5209#issuecomment-564483334

   

  Intel's camera tuning guide offers advice about dealing with strong light, such as defining an auto-exposure Region of Interest in the bottom half of the image.

  https://dev.intelrealsense.com/docs/tuning-depth-cameras-for-best-performance#section-use-sunlight-but-avoid-glare

   

  The negative effects on the image of glare from reflections can also be greatly negated by purchasing and applying a physical thin-film linear polarization filter product over the lenses on the outside of the camera.  Intel's guide on optical filters provides information about this in section 4.4 When to use polarizers and waveplates

  https://dev.intelrealsense.com/docs/optical-filters-for-intel-realsense-depth-cameras-d400#section-4-the-use-of-optical-filters

  Any polarizer filter should work so long as it is linear (ones from 3D glasses will not work).  You can find examples by searching stores such as Amazon for the term linear polarization filter sheet

   

  Intel added a fix to the firmware as far back as firmware version 5.11.4 to correct the problem of the IR image going black when exposed to strong light whilst auto-exposure was enabled.  What firmware version is your camera using, please?

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• Karthikeyan Yuvraj

  • January 31, 2022 21:54
  • Edited

  thanks for the reply. My camera is at 05.11.01.100

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• Karthikeyan Yuvraj

  • January 31, 2022 22:11

  Ok fyi, I updated the camera to the latest version 05.13.00.50 and still, we have the same issue. 

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• MartyG

  • January 31, 2022 22:29

  Are you using RealSense SDK version 2.50.0

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