D435 depth accuracy without infrared projector
We use our D435 cameras in outdoor conditions where temperatures can vary widely (roughly -30C to 55C). From reading RealSense documentation and posts in this support community, I know that the infrared projector will switch off if the infrared laser temperature is below 0C or above 60C, but that the RGB stereo depth readings will likely still be available.
That leads me to two questions:
- What is the difference in depth sensing accuracy with and without the infrared projector?
- Are there temperatures at which even RGB stereo depth readings will deteriorate? In particular, is there a temperature on the low end (e.g., -20C) at which the RGB camera will stop working or the RGB stereo depth readings will deteriorate significantly?
Thanks in advance for the help!
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1. The dot pattern projection cast onto surfaces in the scene aids the camera in analyzing surfaces for depth information. If the projector is off then the depth image will continue to be generated but is likely to have holes in it where no depth data is present.
Where depth data is present on the image, the depth value may be inaccurate due to the difficulty in reading the surfaces.
The D455 camera model supports a thermal compensation feature that automatically adjusts the camera's calibration according to the current temperature.
If external lighting is installed near the camera though then it could use that ambient light instead of the dot pattern for depth analysis. This could be an infrared lamp with invisible light if the outdoor scene must not be illuminated with a conventional visible lamp.
2. The external temperature of the camera casing can affect the internal operating temperature. It may be difficult for the internal temperature to drop as far as 0 degrees though so long as the camera is powered and actively streaming. When the camera is inactive (unpowered), it is rated to withstand exposure to up to -40 degrees C for a short time.
Setting the camera's Laser Power setting to its maximum power value of '360' instead of the default of '156' may help to increase internal temperature during operation.
There is not specific data about how extreme cold would affect a RealSense camera's RGB sensor. In general though, electronics have the potential to become impaired in freezing temperature.
Just as external casing temperature affects internal temperature, a rise in internal temperature should cause the external casing temperature to rise.
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