699 research outputs found
Object-based Illumination Estimation with Rendering-aware Neural Networks
We present a scheme for fast environment light estimation from the RGBD
appearance of individual objects and their local image areas. Conventional
inverse rendering is too computationally demanding for real-time applications,
and the performance of purely learning-based techniques may be limited by the
meager input data available from individual objects. To address these issues,
we propose an approach that takes advantage of physical principles from inverse
rendering to constrain the solution, while also utilizing neural networks to
expedite the more computationally expensive portions of its processing, to
increase robustness to noisy input data as well as to improve temporal and
spatial stability. This results in a rendering-aware system that estimates the
local illumination distribution at an object with high accuracy and in real
time. With the estimated lighting, virtual objects can be rendered in AR
scenarios with shading that is consistent to the real scene, leading to
improved realism.Comment: ECCV 202
The Evolution of First Person Vision Methods: A Survey
The emergence of new wearable technologies such as action cameras and
smart-glasses has increased the interest of computer vision scientists in the
First Person perspective. Nowadays, this field is attracting attention and
investments of companies aiming to develop commercial devices with First Person
Vision recording capabilities. Due to this interest, an increasing demand of
methods to process these videos, possibly in real-time, is expected. Current
approaches present a particular combinations of different image features and
quantitative methods to accomplish specific objectives like object detection,
activity recognition, user machine interaction and so on. This paper summarizes
the evolution of the state of the art in First Person Vision video analysis
between 1997 and 2014, highlighting, among others, most commonly used features,
methods, challenges and opportunities within the field.Comment: First Person Vision, Egocentric Vision, Wearable Devices, Smart
Glasses, Computer Vision, Video Analytics, Human-machine Interactio
Re-identification and semantic retrieval of pedestrians in video surveillance scenarios
Person re-identification consists of recognizing individuals across different sensors of a camera
network. Whereas clothing appearance cues are widely used, other modalities could
be exploited as additional information sources, like anthropometric measures and gait. In
this work we investigate whether the re-identification accuracy of clothing appearance descriptors
can be improved by fusing them with anthropometric measures extracted from
depth data, using RGB-Dsensors, in unconstrained settings. We also propose a dissimilaritybased
framework for building and fusing multi-modal descriptors of pedestrian images for
re-identification tasks, as an alternative to the widely used score-level fusion. The experimental
evaluation is carried out on two data sets including RGB-D data, one of which is a
novel, publicly available data set that we acquired using Kinect sensors.
In this dissertation we also consider a related task, named semantic retrieval of pedestrians
in video surveillance scenarios, which consists of searching images of individuals using
a textual description of clothing appearance as a query, given by a Boolean combination of
predefined attributes. This can be useful in applications like forensic video analysis, where
the query can be obtained froma eyewitness report. We propose a general method for implementing
semantic retrieval as an extension of a given re-identification system that uses any
multiple part-multiple component appearance descriptor. Additionally, we investigate on
deep learning techniques to improve both the accuracy of attribute detectors and generalization
capabilities. Finally, we experimentally evaluate our methods on several benchmark
datasets originally built for re-identification task
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