D455 depth data sometimes has unstable values

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Kawasyuuqq

• May 27, 2024 08:55

I am using python to import pyrealsense and run RealSense.
A few percent of the time, I am not getting the depth data correctly.
It often happens when I take a picture right after connecting to the camera, though,
In this case, no matter how many times you shoot, you will only get partial surface depth.
In most cases, reconnecting the camera with the software will fix the problem.
In most cases, even during normal imaging, the image can be acquired cleanly. (The two pictures are of the same object)

　　　　Normal data

　　　　　　Abnormal data

I would like to keep the items that can be changed in the viewer to fixed values as much as possible.
Right now I have it set up as follows

#####################################################

self.pipeline = rs.pipeline()

self.align = rs.align(rs.stream.color)

rs_config = rs.config()

rs_config.enable_stream(rs.stream.color, 1280, 720, rs.format.bgr8, 5)

rs_config.enable_stream(rs.stream.depth, 1280, 720, rs.format.z16, 5)

self.profile = self.pipeline.start(rs_config)

self.depth_sensor = self.profile.get_device().first_depth_sensor()

self.depth_sensor.set_option(rs.option.emitter_enabled, 1)

self.depth_sensor.set_option(rs.option.enable_auto_exposure, 0)

self.depth_sensor.set_option(rs.option.exposure, 5000)

self.depth_sensor.set_option(rs.option.gain, 16)

self.depth_sensor.set_option(rs.option.laser_power, 360)

self.depth_sensor.set_option(rs.option.depth_units, 0.001)

self.depth_sensor.set_option(rs.option.emitter_on_off, False)

self.depth_sensor.set_option(rs.option.emitter_always_on, 1)

#####################################################
Question 1.
How can I remedy the problem of not being able to acquire depth data properly?
Question 2
In Intel RealSense Viewer v2.55.1, I want to change the settings in the Stereo Module from within the program.
I would like to change all of the "Controls" items and possibly the "Advanced Controls" items.
How do I write a program to change each item?

Translated with DeepL.com (free version)

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• MartyG

  • May 27, 2024 09:55

  Hi Kawasyuuqq  When using auto-exposure, the first several frames may have incorrect exposure because the exposure value is still settling down (this does not occur when using manual exposure).  You can add a line to a script though to skip the first several 'bad' frames.  It should be placed directly before the wait_for_frames() line.

  for i in range(5):

   

  In regard to your second question, you can change the options in the RealSense Viewer's Controls section with code.  There are numerous options though, so if you request a specific one (such as exposure) then I can provide some Python code for it.

   

  If you plan to customize multiple Controls settings then it may be easier to set the values in the Viewer and then use the json save button near the top of the Viewer's options side-panel (beside the camera name) to export a json camera configuration file.  You can then load this json in using your script to apply the settings in the file.

   

  Most of the Advanced Controls do not have Python code available to alter them and also do not have documentation to describe what they do.  This is because the Advanced Controls interact with each other in complex ways, so Intel chose to control them automatically with machine-language algorithms instead of documenting them.

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• Kawasyuuqq

  • June 05, 2024 01:33

  Thank you very much. I tried it.

  for i in range(5):.
  　frames = self.pipeline.wait_for_frames()
  　time.sleep(10/1000)
  time.sleep(3)

  Multiple "pipeline.wait_for_frames()"
  and a 3-second wait.

  In addition, the exposure, gain, and laser power are adjusted manually.
  Each value is adjusted so that the object appears beautiful.
  (For example, if the exposure is set too high, the image will not look good every time.)
  However, it sometimes happens that the image does not stabilize during the subsequent shooting.
  When it was not stable, it was not stable even after dozens of shots.
  This can happen when using the extension repeater or not.
  In most cases, it can be fixed by disconnecting and reconnecting on the software.

   

  >If you plan to customize multiple Controls settings then it may be easier to set the values in the Viewer and then use the json save button near the top of the Viewer's options side-panel (beside the camera name) to export a json camera configuration file.  You can then load this json in using your script to apply the settings in the file.

  I understand. Thank you!

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• MartyG

  • June 05, 2024 09:02

  As manual exposure is being used, if there is an event that causes the image to become over-exposed or under-exposed then the camera will not be able to correct the image automatically if auto-exposure is not enabled.  An example of such an event would be if the camera was facing directly towards a bright light source such as the sun, causing the infrared sensor to become saturated with light. 

   

  If you do not wish to use auto-exposure then you could consider High Dynamic Range (HDR) mode, where auto-exposure is disabled and the camera can alternate between two different exposure values.  This helps the camera to deal with scenes where there are both bright and dark areas.

  https://dev.intelrealsense.com/docs/high-dynamic-range-with-stereoscopic-depth-cameras

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