DepthAI Hallucinates Depth Data

AndrewHatstat

Sometimes the depth data I get from my depthai module seems to have large areas of incorrect depth filled in with high confidence. Is this a known issue or am I doing something wrong? The problem seems to manifest as peninsulas of filled in depth data running horizontally across the image near a depth edge. See attached images. Is there some setting I can change to fix this? My current settings:

stereo_depth->setDefaultProfilePreset(dai::node::StereoDepth::PresetMode::HIGH_ACCURACY);

// Options: MEDIAN_OFF, KERNEL_3x3, KERNEL_5x5, KERNEL_7x7 (default)

stereo_depth->initialConfig.setMedianFilter(dai::MedianFilter::KERNEL_5x5);

stereo_depth->setLeftRightCheck(true);

stereo_depth->setExtendedDisparity(false);

stereo_depth->setSubpixel(true);

stereo_depth->initialConfig.setDisparityShift(0);

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erik

Hi AndrewHatstat ,

It seems like this confidence isn't very high in this region:

So I'd suggest lowering stereo confidence to get more accurate results. I'd also suggest checking Improving Stereo Accuracy documentation.

Thanks, Erik

AndrewHatstat

The incorrect depth comes from the high confidence region. Lowering the threshold to 100 does change the size and shape a bit, but it makes holes in other parts of the image. I see there is a new library version with brightness thresholds. The trouble areas seem to be along high contrast regions that are nearly saturated. Perhaps the brightness filters will help.

erik

Hi AndrewHatstat , I agree, best to try it out - though it might invalidate a lot of the depth map that was previously detected correctly.

AndrewHatstat

erik Reducing the max brightness filter from the default 256 to 255 significantly shrinks the erroneous depth artifact. As you guessed it also creates some new depth holes in saturated areas, for example in the white label on the box. I suppose the key take away is try to avoid saturating the image. In this case I was using auto exposure and the default gain setting.

erik

Hi AndrewHatstat ,
In general, stereo sensors have quite good dynamic range, but it will be hard to have all "blacks" above 0 and all "whites" below 255, as sensors in RVC2 don't do actual HDR. So usually AE will accomplish that all dark pixels are below 0, and will rather over saturate bright pixels, so quite a few of them will be 255.
Thanks, Erik