16 research outputs found
End-to-end Lane Detection through Differentiable Least-Squares Fitting
Lane detection is typically tackled with a two-step pipeline in which a
segmentation mask of the lane markings is predicted first, and a lane line
model (like a parabola or spline) is fitted to the post-processed mask next.
The problem with such a two-step approach is that the parameters of the network
are not optimized for the true task of interest (estimating the lane curvature
parameters) but for a proxy task (segmenting the lane markings), resulting in
sub-optimal performance. In this work, we propose a method to train a lane
detector in an end-to-end manner, directly regressing the lane parameters. The
architecture consists of two components: a deep network that predicts a
segmentation-like weight map for each lane line, and a differentiable
least-squares fitting module that returns for each map the parameters of the
best-fitting curve in the weighted least-squares sense. These parameters can
subsequently be supervised with a loss function of choice. Our method relies on
the observation that it is possible to backpropagate through a least-squares
fitting procedure. This leads to an end-to-end method where the features are
optimized for the true task of interest: the network implicitly learns to
generate features that prevent instabilities during the model fitting step, as
opposed to two-step pipelines that need to handle outliers with heuristics.
Additionally, the system is not just a black box but offers a degree of
interpretability because the intermediately generated segmentation-like weight
maps can be inspected and visualized. Code and a video is available at
github.com/wvangansbeke/LaneDetection_End2End.Comment: Accepted at ICCVW 2019 (CVRSUAD-Road Scene Understanding and
Autonomous Driving
CurveFormer: 3D Lane Detection by Curve Propagation with Curve Queries and Attention
3D lane detection is an integral part of autonomous driving systems. Previous
CNN and Transformer-based methods usually first generate a bird's-eye-view
(BEV) feature map from the front view image, and then use a sub-network with
BEV feature map as input to predict 3D lanes. Such approaches require an
explicit view transformation between BEV and front view, which itself is still
a challenging problem. In this paper, we propose CurveFormer, a single-stage
Transformer-based method that directly calculates 3D lane parameters and can
circumvent the difficult view transformation step. Specifically, we formulate
3D lane detection as a curve propagation problem by using curve queries. A 3D
lane query is represented by a dynamic and ordered anchor point set. In this
way, queries with curve representation in Transformer decoder iteratively
refine the 3D lane detection results. Moreover, a curve cross-attention module
is introduced to compute the similarities between curve queries and image
features. Additionally, a context sampling module that can capture more
relative image features of a curve query is provided to further boost the 3D
lane detection performance. We evaluate our method for 3D lane detection on
both synthetic and real-world datasets, and the experimental results show that
our method achieves promising performance compared with the state-of-the-art
approaches. The effectiveness of each component is validated via ablation
studies as well