Tracking Quality

introduction there are essentially two possible issues to look for when considering the tracking quality of the system noise this is sometimes referred to as "jitter" and is essentially small erratic movements in the cg graphic when the camera is stationary it's really important to understand a few things about noise though to some degree it is always present, typically though with a properly calibrated camera bar and good tracking environment, then it should be imperceptible to the eye the quality of the tracking points will normally be the determining factor in how much noise is present that is to say, you could have a perfectly calibrated camera bar but lots of noise/jitter in the graphic because you are working in a bad tracking environment (lots of moving points and changing lighting) you can never calibrate yourself out of not having enough tracking points! when using natural tracking, it's not uncommon for noise to gradually present itself over extended usage, this is expected and can be managed in a number of ways locking the pointcloud or refreshing the pointcloud (either manually using alt+r or using the auto refresh option set in the full ui preferences) the clip below shows a representation of what we mean by noise/jitter this page will discuss how the camera bar calibration can be improved to minimize noise due to calibration and assumes the tracking environment is adequate scale issues with scale are typically diagnosed by cg graphics gradually drifting from where they have been placed as the camera moves further from them this typically indicates that the tracking is moving more/less than the actual camera is moving some experience is required to identify whether this drifting in the graphic is due to stereo however, as it could also be caused by issues with lens calibration, witness to main relationship or even the graphic being poorly positioned in 3d space additionally, high pixel errors immediately after starting tracking (above 0 5), or the dropping in and out of detection of large groups of tracking points are typically indicative of a poor calibration before conducting any camera bar calibration, make sure that the issue you are experiencing is not a result of bad lens calibration bad positioning of a graphic/zero point bad witness to main relationship camera bar calibration should be treated as a last resort after confirming everything else is working as intended steps to improve bundle adjustment we can try and improve the camera bar calibration by conducting what we refer to as a " bundle adjustment " this is a process where the camera bar improves it's calibration based off the pointcloud for the bundle adjustment to work well it's important that there is a good tracking environment around the camera bar good stable tracking points in a close to medium range to the camera bar, around 2 10 metres stable consistent lighting flat textured surfaces posters, logos etc bad points mostly far away, camera bar at the top of a tower, or looking out a window for example trees/foliage moving lighting reflective surfaces once you've set the camera bar up in an area that has good tracking, the following steps can be taken put the camera bar into "raw" mode, this is done in the preferences of the full ui clear our the pointcloud so that we start with a fresh pointcloud start tracking, there is no need to set an origin/zero point move the camera bar so that around 10 30 key positions are generated, this is typically 2 3 metres of movement make sure the camera bar is looking at a good tracking area when doing this movement select " re optimize all the parameters " from the devices > camera bar > advanced calibration menu ncam reality will attempt to improve the calibration, a pop up window will display showing the user how the calibration has been modified pressing cancel, will disregard the calibration completely, pressing ok will temporarily save the calibration until the next time the ncam reality software is restarted this is done intentionally as it allows you to test the quality of the calibration without committing permanently to it start the system tracking again and decide if the tracking quality has improved if it has, the calibration can be made permanent by choosing " save current parameters " from the same " advanced calibration " dropdown menu if the system seems to be operating worse than before, simply restart ncam reality without saving the calibration to revert to the prior calibration after saving the updated calibration, ncam reality must be restarted! the following video demonstrates the process issues refinement failure occasionally the bundle adjustment can fail to resolve a solution, this is displayed to the user by the following error message this can be caused by trying to do a bundle adjustment with too large of a pointcloud try deleting the pointcloud and retrying the process with slightly less movement of the camera bar if the process consistently fails, it suggests that there is an underlying problem with the camera bar calibration, contact support\@ncam tech com for further troubleshooting support factory reset it is possible to revert the camera bar back to it's original calibration this may be required if a very bad bundle adjustment has been conducted and saved to the bar for instance simply select " reset to factory calibration " from the devices dropdown menu