Depth issue on the black surface resolution
Hi, I'm planning to use Realsense camera, especially 'D' series.
However, based on my experience with other RGBD camera measuring depth with IR sensors, I remember that black surfaces are not detected well.
I read the specification about D405, D435, and I found that they get depth data through stereoscopic way.
I don't have so much expertise in camera, so, my point of view, the word 'stereoscopic' seems that those cameras are not using IR sensors and measuring with stereo RGB sensor.
And my question is,
1. What I understood about 'stereoscopic' is right?
2. Are those cameras ('D' series) can detect the surface which is the weakness of IR cameras (black surface or etc.)?
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Hi Sohwa427 Thanks very much for your questions.
1. RealSense 400 Series stereo cameras do not use RGB to generate depth data. The camera has a left and right infrared sensor (hence the term 'stereo') and captures a raw left and right infrared image and constructs a depth frame from them. Intel's Beginner's Guide to Depth at the link below provides an explanation of the basic principles of stereo depth.
https://www.intelrealsense.com/beginners-guide-to-depth/
The precise explanation of how a 400 Series camera constructs a depth frame is below. It is taken from pages 18 and 19 of the data sheet document for the 400 Series.
https://dev.intelrealsense.com/docs/intel-realsense-d400-series-product-family-datasheet
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The stereo vision implementation consists of a left imager, right imager and an optional infrared projector. The infrared projector projects a non-visible static IR pattern to improve depth accuracy in scenes with low texture. The left and right imagers capture the scene and send imager data to the depth imaging (vision) processor, which calculates depth values for each pixel in the image by correlating points on the left image to the right image and via the shift between a point on the Left image and the Right image. The depth pixel values are processed
to generate a depth frame. Subsequent depth frames create a depth video stream.**********
2. It is a general physics principle (not specific to RealSense) that dark gray or black absorbs light and so makes it more difficult for depth cameras to read depth information from such surfaces. The darker the color shade, the more light that is absorbed and so the less depth detail that the camera can obtain. Casting a strong light source onto such a surface can help to bring out depth detail.
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Thank you MartyG, for the great, kind comment!
I will read the documents you gave! Thank you again.
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