1,240 research outputs found
Online Adaptation of Convolutional Neural Networks for Video Object Segmentation
We tackle the task of semi-supervised video object segmentation, i.e.
segmenting the pixels belonging to an object in the video using the ground
truth pixel mask for the first frame. We build on the recently introduced
one-shot video object segmentation (OSVOS) approach which uses a pretrained
network and fine-tunes it on the first frame. While achieving impressive
performance, at test time OSVOS uses the fine-tuned network in unchanged form
and is not able to adapt to large changes in object appearance. To overcome
this limitation, we propose Online Adaptive Video Object Segmentation (OnAVOS)
which updates the network online using training examples selected based on the
confidence of the network and the spatial configuration. Additionally, we add a
pretraining step based on objectness, which is learned on PASCAL. Our
experiments show that both extensions are highly effective and improve the
state of the art on DAVIS to an intersection-over-union score of 85.7%.Comment: Accepted at BMVC 2017. This version contains minor changes for the
camera ready versio
Deep Semantic Classification for 3D LiDAR Data
Robots are expected to operate autonomously in dynamic environments.
Understanding the underlying dynamic characteristics of objects is a key
enabler for achieving this goal. In this paper, we propose a method for
pointwise semantic classification of 3D LiDAR data into three classes:
non-movable, movable and dynamic. We concentrate on understanding these
specific semantics because they characterize important information required for
an autonomous system. Non-movable points in the scene belong to unchanging
segments of the environment, whereas the remaining classes corresponds to the
changing parts of the scene. The difference between the movable and dynamic
class is their motion state. The dynamic points can be perceived as moving,
whereas movable objects can move, but are perceived as static. To learn the
distinction between movable and non-movable points in the environment, we
introduce an approach based on deep neural network and for detecting the
dynamic points, we estimate pointwise motion. We propose a Bayes filter
framework for combining the learned semantic cues with the motion cues to infer
the required semantic classification. In extensive experiments, we compare our
approach with other methods on a standard benchmark dataset and report
competitive results in comparison to the existing state-of-the-art.
Furthermore, we show an improvement in the classification of points by
combining the semantic cues retrieved from the neural network with the motion
cues.Comment: 8 pages to be published in IROS 201
Object-Proposal Evaluation Protocol is 'Gameable'
Object proposals have quickly become the de-facto pre-processing step in a
number of vision pipelines (for object detection, object discovery, and other
tasks). Their performance is usually evaluated on partially annotated datasets.
In this paper, we argue that the choice of using a partially annotated dataset
for evaluation of object proposals is problematic -- as we demonstrate via a
thought experiment, the evaluation protocol is 'gameable', in the sense that
progress under this protocol does not necessarily correspond to a "better"
category independent object proposal algorithm.
To alleviate this problem, we: (1) Introduce a nearly-fully annotated version
of PASCAL VOC dataset, which serves as a test-bed to check if object proposal
techniques are overfitting to a particular list of categories. (2) Perform an
exhaustive evaluation of object proposal methods on our introduced nearly-fully
annotated PASCAL dataset and perform cross-dataset generalization experiments;
and (3) Introduce a diagnostic experiment to detect the bias capacity in an
object proposal algorithm. This tool circumvents the need to collect a densely
annotated dataset, which can be expensive and cumbersome to collect. Finally,
we plan to release an easy-to-use toolbox which combines various publicly
available implementations of object proposal algorithms which standardizes the
proposal generation and evaluation so that new methods can be added and
evaluated on different datasets. We hope that the results presented in the
paper will motivate the community to test the category independence of various
object proposal methods by carefully choosing the evaluation protocol.Comment: 15 pages, 11 figures, 4 table
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