27 research outputs found
Deep Learning for Vanishing Point Detection Using an Inverse Gnomonic Projection
We present a novel approach for vanishing point detection from uncalibrated
monocular images. In contrast to state-of-the-art, we make no a priori
assumptions about the observed scene. Our method is based on a convolutional
neural network (CNN) which does not use natural images, but a Gaussian sphere
representation arising from an inverse gnomonic projection of lines detected in
an image. This allows us to rely on synthetic data for training, eliminating
the need for labelled images. Our method achieves competitive performance on
three horizon estimation benchmark datasets. We further highlight some
additional use cases for which our vanishing point detection algorithm can be
used.Comment: Accepted for publication at German Conference on Pattern Recognition
(GCPR) 2017. This research was supported by German Research Foundation DFG
within Priority Research Programme 1894 "Volunteered Geographic Information:
Interpretation, Visualisation and Social Computing
HoughNet: neural network architecture for vanishing points detection
In this paper we introduce a novel neural network architecture based on Fast
Hough Transform layer. The layer of this type allows our neural network to
accumulate features from linear areas across the entire image instead of local
areas. We demonstrate its potential by solving the problem of vanishing points
detection in the images of documents. Such problem occurs when dealing with
camera shots of the documents in uncontrolled conditions. In this case, the
document image can suffer several specific distortions including projective
transform. To train our model, we use MIDV-500 dataset and provide testing
results. The strong generalization ability of the suggested method is proven
with its applying to a completely different ICDAR 2011 dewarping contest. In
previously published papers considering these dataset authors measured the
quality of vanishing point detection by counting correctly recognized words
with open OCR engine Tesseract. To compare with them, we reproduce this
experiment and show that our method outperforms the state-of-the-art result.Comment: 6 pages, 6 figures, 2 tables, 28 references, conferenc
Object Recognition from very few Training Examples for Enhancing Bicycle Maps
In recent years, data-driven methods have shown great success for extracting
information about the infrastructure in urban areas. These algorithms are
usually trained on large datasets consisting of thousands or millions of
labeled training examples. While large datasets have been published regarding
cars, for cyclists very few labeled data is available although appearance,
point of view, and positioning of even relevant objects differ. Unfortunately,
labeling data is costly and requires a huge amount of work. In this paper, we
thus address the problem of learning with very few labels. The aim is to
recognize particular traffic signs in crowdsourced data to collect information
which is of interest to cyclists. We propose a system for object recognition
that is trained with only 15 examples per class on average. To achieve this, we
combine the advantages of convolutional neural networks and random forests to
learn a patch-wise classifier. In the next step, we map the random forest to a
neural network and transform the classifier to a fully convolutional network.
Thereby, the processing of full images is significantly accelerated and
bounding boxes can be predicted. Finally, we integrate data of the Global
Positioning System (GPS) to localize the predictions on the map. In comparison
to Faster R-CNN and other networks for object recognition or algorithms for
transfer learning, we considerably reduce the required amount of labeled data.
We demonstrate good performance on the recognition of traffic signs for
cyclists as well as their localization in maps.Comment: Submitted to IV 2018. This research was supported by German Research
Foundation DFG within Priority Research Programme 1894 "Volunteered
Geographic Information: Interpretation, Visualization and Social Computing
Temporally Consistent Horizon Lines
The horizon line is an important geometric feature for many image processing
and scene understanding tasks in computer vision. For instance, in navigation
of autonomous vehicles or driver assistance, it can be used to improve 3D
reconstruction as well as for semantic interpretation of dynamic environments.
While both algorithms and datasets exist for single images, the problem of
horizon line estimation from video sequences has not gained attention. In this
paper, we show how convolutional neural networks are able to utilise the
temporal consistency imposed by video sequences in order to increase the
accuracy and reduce the variance of horizon line estimates. A novel CNN
architecture with an improved residual convolutional LSTM is presented for
temporally consistent horizon line estimation. We propose an adaptive loss
function that ensures stable training as well as accurate results. Furthermore,
we introduce an extension of the KITTI dataset which contains precise horizon
line labels for 43699 images across 72 video sequences. A comprehensive
evaluation shows that the proposed approach consistently achieves superior
performance compared with existing methods
CONSAC: Robust Multi-Model Fitting by Conditional Sample Consensus
We present a robust estimator for fitting multiple parametric models of the
same form to noisy measurements. Applications include finding multiple
vanishing points in man-made scenes, fitting planes to architectural imagery,
or estimating multiple rigid motions within the same sequence. In contrast to
previous works, which resorted to hand-crafted search strategies for multiple
model detection, we learn the search strategy from data. A neural network
conditioned on previously detected models guides a RANSAC estimator to
different subsets of all measurements, thereby finding model instances one
after another. We train our method supervised as well as self-supervised. For
supervised training of the search strategy, we contribute a new dataset for
vanishing point estimation. Leveraging this dataset, the proposed algorithm is
superior with respect to other robust estimators as well as to designated
vanishing point estimation algorithms. For self-supervised learning of the
search, we evaluate the proposed algorithm on multi-homography estimation and
demonstrate an accuracy that is superior to state-of-the-art methods.Comment: CVPR 202
Quantitative electron microscopy for microstructural characterisation
Development of materials for high-performance applications requires accurate and useful analysis tools. In parallel with advances in electron microscopy hardware, we require analysis approaches to better understand microstructural behaviour. Such improvements in characterisation capability permit informed alloy design.
New approaches to the characterisation of metallic materials are presented, primarily using signals collected from electron microscopy experiments. Electron backscatter diffraction is regularly used to investigate crystallography in the scanning electron microscope, and combined with energy-dispersive X-ray spectroscopy to simultaneusly investigate chemistry. New algorithms and analysis pipelines are developed to permit accurate and routine microstructural evaluation, leveraging a variety of machine learning approaches. This thesis investigates the structure and behaviour of Co/Ni-base superalloys, derived from V208C. Use of the presently developed techniques permits informed development of a new generation of advanced gas turbine engine materials.Open Acces