Posted by
Montana on
URL: http://official-rtab-map-forum.206.s1.nabble.com/Missing-Frames-tp7840p7928.html
Thanks for the reply. I've collected some data directly from the sensors with nothing else running to help shed some light on the issue.
For all of these the columns are the DELTAS (time between frames) for color+depth of the following functions, in their native units:
frame.get_timestamp(), frame.get_frame_metadata(RS2_FRAME_METADATA_FRAME_TIMESTAMP), frame.get_frame_metadata(RS2_FRAME_METADATA_TIME_OF_ARRIVAL)
First dataset is from only the D435I with GLOBAL_TIME_ENABLED=0 (off)
69.89, 66720, 66
67.77, 66720, 67
65.66, 66720, 67
5,918.18, 66720, 67
67.27, 66720, 66
67.28, 66720, 67
69.37, 66720, 68
65.17, 66720, 66
69.38, 66720, 67
67.27, 66720, 67
65.17, 66720, 66
67.28, 66720, 67
69.37, 66720, 66
67.28, 66720, 67
67.27, 66720, 67
67.27, 66720, 66
67.28, 66720, 67
69.37, 66720, 67
2,595.55, 66720, 67
67.06, 66720, 66
Second dataset is from only the D435I with GLOBAL_TIME_ENABLED=1 (on)
68.67, 66720, 67
66.60, 66720, 66
66.59, 66720, 67
66.59, 66720, 67
100.86, 66720, 67
64.51, 66720, 66
68.68, 66720, 67
66.59, 66720, 67
64.51, 66720, 66
68.68, 66720, 67
66.59, 66720, 67
66.59, 66720, 67
64.52, 66720, 66
68.67, 66720, 67
68.68, 66720, 67
66.59, 66720, 67
66.59, 66720, 66
66.60, 66720, 67
66.59, 66720, 67
86.49, 66720, 66
Third dataset is from both the D435I and T265 with GLOBAL_TIME_ENABLED=1 (on)
66.79, 66720, 67
485.06, 66720, 66
66.76, 66720, 67
68.84, 66720, 67
66.76, 66720, 67
66.76, 66720, 66
66.75, 66720, 67
66.76, 66720, 67
68.85, 66720, 67
66.75, 66720, 66
64.68, 66720, 67
68.84, 66720, 67
66.76, 66720, 66
68.84, 66720, 67
66.76, 66720, 67
64.67, 66720, 66
428.70, 66720, 67
66.73, 66720, 67
66.72, 66720, 66
As you can see the first column, representing frame.get_timestamp() and the supposed sensor timestamp for when the sample was taken, is entirely unreliable. I went ahead and installed realsense and rtabmap on a windows PC, and the same issue seems to apply there as well. Using only an D435I and global timestamps there are few, if any, instances of the missing frame error. Using the dual mode with the T265 plugged in and they seem to crop up often. I feel like someone else should have seen this behavior, since these are pretty popular sensors, but maybe there is some other option or influencing factor. Meanwhile I have been rewriting the realsense2 camera driver to account for this and some other issues, but it may not be suitable to give back to the project when I am done.