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Xtion shows artifact in line mode
Dave Everett from Australia  [18 posts]
4 years
I have an Xtion Pro Live running in roborealm 320x240, line mode with the max min set at 61, 59.
No matter where the camera faces I have an artifact at about column 317 on. This does not show up in gray mode or in other programs like openni SimpleViewer.

I've attached a snap. The other peaks are somewhat odd as well, in that the camera is about 1m above the ground, facing forwards towards an open doorway at a distance of about 2m.

Dave

 
Steven Gentner from United States  [1371 posts] 4 years
Dave,

Can you include the depth map image (in grayscale) so that we can check to see if there is something wrong with the depth image capture or the line image generation.

Thanks,
STeven.
Dave Everett from Australia  [18 posts] 4 years
Here are the same views in both modes. You can see a black area on the right in the greyscale image.

  
Steven Gentner from United States  [1371 posts] 4 years
Dave,

Those black vertical lines would explain the spikes you are seeing in the line image. When you move the Xtion around do the lines stay in the exact same location or are they attached to the door hinge. (I'm assuming those are caused by a door to the room).

It could very well be that the Xtion is just not processing that part of the image correctly. The black line at the far right of the image is probably caused by adding the 4 byte alignment that Windows needs for image widths. That's being done in the NI drivers. You can use the crop module to remove those last 4 pixels if needed ... or just ignore them. I'd expect that they are always present in the same location (far right). But I'd also expect that the other 2 that we see will move with the image.

Keep in mind that both the Xtion and the Kinect use IR dots to calculate depth. Its very important that it sees those dots otherwise depth will not be calculated correctly. As those lines do seem like attributes in the image I don't think it is an encoding or transmission of data error but rather something in the scene that is IR reflective and causing the Xtion not to see its IR dots. If those lines move when you move the Xtion that would validate it.

STeven.
Dave Everett from Australia  [18 posts] 4 years
Thanks Steve, yeah the other lines are definitely a door edge too close and part of the wall that can't be seen properly.

I had been cropping, but I thought that might just be hiding a problem, however those alignment bytes would explain the issue although I could not see them in SimpleViewer, I guess the Openni app hides them.

Thanks for looking in to it.

Dave

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