Why does my D455 measure a larger range at the edge and a smaller range at the center？

[AmazingSealock]

Required Info
Camera Model	D455
Firmware Version	05.12.06.00
Operating System & Version	ubuntu18.04
Kernel Version (Linux Only)	4.15.0-123-generic
Platform	PC
SDK Version	v2.36.0 }
Language	c++
Segment	Robot

Issue Description

When looking for a flat plate four meters away, it was found that the center area could not be measured, but by turning the camera, the edge area could be measured.

This is when the camera is centered on the plate no plate

This is when the tablet appears at the edge of a deep image you can see there is a dark red plate The distance is about 4m, So , why do I meet this problem. This is that plate.

[MartyG-RealSense]

Hi @AmazingSealock If you are observing the set of six plates in a black framework, it is possible that the camera is interpreting it as a repetitive pattern. Having horizontal or vertical repeating patterns in a scene (such as window blinds or a row of fence posts) can confuse the camera. Turning the camera may disrupt that repetitive pattern.

The subject of repetitive patterns is discussed in the link below.

https://github.com/IntelRealSense/librealsense/issues/6713

Within that case, links to resources about methods that may help to negate the effect are provided.

https://github.com/IntelRealSense/librealsense/issues/6713#issuecomment-651114720

Repetitive patterns and ways to combat them are also discussed in the link below.

https://github.com/IntelRealSense/librealsense/issues/4082

[AmazingSealock]

Thank you @MartyG-RealSense, I've now switched to looking for a bucket in the depth Image, but there's still a problem. It doesn't look like the repetitive pattern caused this. I've already calibrated my D455.

[MartyG-RealSense]

For the D455, the recommended optimal depth accuracy resolution - like with the D435 and D435i models - is 848x480 . If you have been using 1280x720 for depth, (like the RGB resolution in the Viewer image above) do your results improve if you use 848x480 please?

[MartyG-RealSense]

Hi @AmazingSealock Do you require further assistance with this case, please? Thanks!

[MartyG-RealSense]

Case closed due to no further comments received.

[AmazingSealock]

Thank you, I sovlede this problem!

[MartyG-RealSense]

Great to hear - thanks for the update :)