Why are my map and anchor residuals worse when I use control points

Introduction

Problem description

Using control points makes the quality of the scan worse and not better.  

Troubleshooting procedure

1 An issue with the surveyed control points file

To determine if it is this issue, contact the person who surveyed the points.

2 An issue with the sensor frame (IMMS calibration file), in particular with the belt hook sizes.

To determine if it is this issue issue, open the sensor_frame.xml file from the problematic Dataset and compare it to a sensor_frame.xml file of another device (which is known to function well). On an example below, the problematic device is left and good one is right. If you look at the L size of the belt hook, you can see that the z value is ~10cm off from the other VLX. Also comparing the L size to other sizes (M, S, XS) we see that the values don't go in an equal sequence with around 3cm space between the (along z axis). This is a good indicator that something is wrong with the calibration file and you have to consult Neeti or Humberto from MAP team to generate a new file.

3 An issue when capturing control points.

Last but not least, to verify if the issue is coming from the 3rd root cause, check the control points location on the panorama images and compare them to the marker on the quality map. For example, points 68 and 69 are placed on the container (what we call wall-mounted points). The black cross that marks their location on the quality map (picture below) should therefore be directly on the white line representing the surface of the container. However, this is not the case and it indicates that the Add button was pressed too soon or too late.

For comparison, a wall-mounted control point should look like this, directly on the wall:

You will know if you have captured a wall-mounted control point correctly during the scanning if the circular yellow marker looks perpendicular to the viewing perspective. Compare how it looks for a control point on the floor and the one on the wall (named "wall1"):

Reference

Review how to correctly capture a control point, refer to the documentation on control points.