14,332 research outputs found
TrackletMapper: Ground Surface Segmentation and Mapping from Traffic Participant Trajectories
Robustly classifying ground infrastructure such as roads and street crossings
is an essential task for mobile robots operating alongside pedestrians. While
many semantic segmentation datasets are available for autonomous vehicles,
models trained on such datasets exhibit a large domain gap when deployed on
robots operating in pedestrian spaces. Manually annotating images recorded from
pedestrian viewpoints is both expensive and time-consuming. To overcome this
challenge, we propose TrackletMapper, a framework for annotating ground surface
types such as sidewalks, roads, and street crossings from object tracklets
without requiring human-annotated data. To this end, we project the robot
ego-trajectory and the paths of other traffic participants into the ego-view
camera images, creating sparse semantic annotations for multiple types of
ground surfaces from which a ground segmentation model can be trained. We
further show that the model can be self-distilled for additional performance
benefits by aggregating a ground surface map and projecting it into the camera
images, creating a denser set of training annotations compared to the sparse
tracklet annotations. We qualitatively and quantitatively attest our findings
on a novel large-scale dataset for mobile robots operating in pedestrian areas.
Code and dataset will be made available at
http://trackletmapper.cs.uni-freiburg.de.Comment: 19 pages, 14 figures, CoRL 2022 v
Cross-View Image Synthesis using Conditional GANs
Learning to generate natural scenes has always been a challenging task in
computer vision. It is even more painstaking when the generation is conditioned
on images with drastically different views. This is mainly because
understanding, corresponding, and transforming appearance and semantic
information across the views is not trivial. In this paper, we attempt to solve
the novel problem of cross-view image synthesis, aerial to street-view and vice
versa, using conditional generative adversarial networks (cGAN). Two new
architectures called Crossview Fork (X-Fork) and Crossview Sequential (X-Seq)
are proposed to generate scenes with resolutions of 64x64 and 256x256 pixels.
X-Fork architecture has a single discriminator and a single generator. The
generator hallucinates both the image and its semantic segmentation in the
target view. X-Seq architecture utilizes two cGANs. The first one generates the
target image which is subsequently fed to the second cGAN for generating its
corresponding semantic segmentation map. The feedback from the second cGAN
helps the first cGAN generate sharper images. Both of our proposed
architectures learn to generate natural images as well as their semantic
segmentation maps. The proposed methods show that they are able to capture and
maintain the true semantics of objects in source and target views better than
the traditional image-to-image translation method which considers only the
visual appearance of the scene. Extensive qualitative and quantitative
evaluations support the effectiveness of our frameworks, compared to two state
of the art methods, for natural scene generation across drastically different
views.Comment: Accepted at CVPR 201
Semantic Instance Annotation of Street Scenes by 3D to 2D Label Transfer
Semantic annotations are vital for training models for object recognition,
semantic segmentation or scene understanding. Unfortunately, pixelwise
annotation of images at very large scale is labor-intensive and only little
labeled data is available, particularly at instance level and for street
scenes. In this paper, we propose to tackle this problem by lifting the
semantic instance labeling task from 2D into 3D. Given reconstructions from
stereo or laser data, we annotate static 3D scene elements with rough bounding
primitives and develop a model which transfers this information into the image
domain. We leverage our method to obtain 2D labels for a novel suburban video
dataset which we have collected, resulting in 400k semantic and instance image
annotations. A comparison of our method to state-of-the-art label transfer
baselines reveals that 3D information enables more efficient annotation while
at the same time resulting in improved accuracy and time-coherent labels.Comment: 10 pages in Conference on Computer Vision and Pattern Recognition
(CVPR), 201
Layered Interpretation of Street View Images
We propose a layered street view model to encode both depth and semantic
information on street view images for autonomous driving. Recently, stixels,
stix-mantics, and tiered scene labeling methods have been proposed to model
street view images. We propose a 4-layer street view model, a compact
representation over the recently proposed stix-mantics model. Our layers encode
semantic classes like ground, pedestrians, vehicles, buildings, and sky in
addition to the depths. The only input to our algorithm is a pair of stereo
images. We use a deep neural network to extract the appearance features for
semantic classes. We use a simple and an efficient inference algorithm to
jointly estimate both semantic classes and layered depth values. Our method
outperforms other competing approaches in Daimler urban scene segmentation
dataset. Our algorithm is massively parallelizable, allowing a GPU
implementation with a processing speed about 9 fps.Comment: The paper will be presented in the 2015 Robotics: Science and Systems
Conference (RSS
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