2020-05-13

Bugfix: HDMAPMDK-1211 found a solution

• Root cause: unreasonable segmentation of the production line

Root cause analysis

It can be seen that segmentation occurred before the lane change was complete (the lane center line was crossing the lane line), and such segmentation may cross Rp.

Since the lane border observation information attached to the lane center shape points faithfully records the lane lines on both sides based on geometry using the scan line method without semantic filtering, the lane center line that intersects with the lane line will record that lane line simultaneously in both left and right lane border refs at the location where the lane line crosses the lane.

In the current code logic, when filtering the border refs of intersecting lane lines based on semantics, the border refs to be deleted are inferred according to the lane change type.

However, the current logic fails when encountering such segmentation, leading to this issue.

Solution

The core point is to find the lane change trend of the intersecting lane lines. Considering that such segmentation may cross the Rp, filtering should not be performed on a per-Rp basis.

1. First, organize lane lines into paths using edge lifting (considering future graph reconstruction): Seq[LaneCenter]
2. Find the lane center to be corrected and the lane border to be corrected (assuming that such lane centers are definitely caused by lane changes)
3. Calculate the lane change trend of the lane center based on the lane center path
4. Perform filtering

Assigned to Ziliang

Interviewed one person, didn’t pass.