7,398 research outputs found
What-and-Where to Match: Deep Spatially Multiplicative Integration Networks for Person Re-identification
Matching pedestrians across disjoint camera views, known as person
re-identification (re-id), is a challenging problem that is of importance to
visual recognition and surveillance. Most existing methods exploit local
regions within spatial manipulation to perform matching in local
correspondence. However, they essentially extract \emph{fixed} representations
from pre-divided regions for each image and perform matching based on the
extracted representation subsequently. For models in this pipeline, local finer
patterns that are crucial to distinguish positive pairs from negative ones
cannot be captured, and thus making them underperformed. In this paper, we
propose a novel deep multiplicative integration gating function, which answers
the question of \emph{what-and-where to match} for effective person re-id. To
address \emph{what} to match, our deep network emphasizes common local patterns
by learning joint representations in a multiplicative way. The network
comprises two Convolutional Neural Networks (CNNs) to extract convolutional
activations, and generates relevant descriptors for pedestrian matching. This
thus, leads to flexible representations for pair-wise images. To address
\emph{where} to match, we combat the spatial misalignment by performing
spatially recurrent pooling via a four-directional recurrent neural network to
impose spatial dependency over all positions with respect to the entire image.
The proposed network is designed to be end-to-end trainable to characterize
local pairwise feature interactions in a spatially aligned manner. To
demonstrate the superiority of our method, extensive experiments are conducted
over three benchmark data sets: VIPeR, CUHK03 and Market-1501.Comment: Published at Pattern Recognition, Elsevie
Joint Detection and Tracking in Videos with Identification Features
Recent works have shown that combining object detection and tracking tasks,
in the case of video data, results in higher performance for both tasks, but
they require a high frame-rate as a strict requirement for performance. This is
assumption is often violated in real-world applications, when models run on
embedded devices, often at only a few frames per second.
Videos at low frame-rate suffer from large object displacements. Here
re-identification features may support to match large-displaced object
detections, but current joint detection and re-identification formulations
degrade the detector performance, as these two are contrasting tasks. In the
real-world application having separate detector and re-id models is often not
feasible, as both the memory and runtime effectively double.
Towards robust long-term tracking applicable to reduced-computational-power
devices, we propose the first joint optimization of detection, tracking and
re-identification features for videos. Notably, our joint optimization
maintains the detector performance, a typical multi-task challenge. At
inference time, we leverage detections for tracking (tracking-by-detection)
when the objects are visible, detectable and slowly moving in the image. We
leverage instead re-identification features to match objects which disappeared
(e.g. due to occlusion) for several frames or were not tracked due to fast
motion (or low-frame-rate videos). Our proposed method reaches the
state-of-the-art on MOT, it ranks 1st in the UA-DETRAC'18 tracking challenge
among online trackers, and 3rd overall.Comment: Accepted at Image and Vision Computing Journa
Structured learning of metric ensembles with application to person re-identification
Matching individuals across non-overlapping camera networks, known as person
re-identification, is a fundamentally challenging problem due to the large
visual appearance changes caused by variations of viewpoints, lighting, and
occlusion. Approaches in literature can be categoried into two streams: The
first stream is to develop reliable features against realistic conditions by
combining several visual features in a pre-defined way; the second stream is to
learn a metric from training data to ensure strong inter-class differences and
intra-class similarities. However, seeking an optimal combination of visual
features which is generic yet adaptive to different benchmarks is a unsoved
problem, and metric learning models easily get over-fitted due to the scarcity
of training data in person re-identification. In this paper, we propose two
effective structured learning based approaches which explore the adaptive
effects of visual features in recognizing persons in different benchmark data
sets. Our framework is built on the basis of multiple low-level visual features
with an optimal ensemble of their metrics. We formulate two optimization
algorithms, CMCtriplet and CMCstruct, which directly optimize evaluation
measures commonly used in person re-identification, also known as the
Cumulative Matching Characteristic (CMC) curve.Comment: 16 pages. Extended version of "Learning to Rank in Person
Re-Identification With Metric Ensembles", at
http://www.cv-foundation.org/openaccess/content_cvpr_2015/html/Paisitkriangkrai_Learning_to_Rank_2015_CVPR_paper.html.
arXiv admin note: text overlap with arXiv:1503.0154
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