Abstract
Minimization of labeling effort for person reidentification in camera networks is an important problem
as most of the existing popular methods are supervised and
they require large amount of manual annotations, acquiring
which is a tedious job. In this work, we focus on this labeling
effort minimization problem and approach it as a subset
selection task where the objective is to select an optimal
subset of image-pairs for labeling without compromising
performance. Towards this goal, our proposed scheme first
represents any camera network (with k number of cameras)
as an edge weighted complete k-partite graph where each
vertex denotes a person and similarity scores between
persons are used as edge-weights. Then in the second
stage, our algorithm selects an optimal subset of pairs by
solving a triangle free subgraph maximization problem on
the k-partite graph. This sub-graph weight maximization
problem is NP-hard (at least for k ? 4) which means for
large datasets the optimization problem becomes intractable.
In order to make our framework scalable, we propose two
polynomial time approximately-optimal algorithms. The
first algorithm is a 1/2-approximation algorithm which
runs in linear time in the number of edges. The second
algorithm is a greedy algorithm with sub-quadratic (in
number of edges) time-complexity. Experiments on three
state-of-the-art datasets depict that the proposed approach
requires on an average only 8-15% manually labeled pairs
in order to achieve the performance when all the pairs are
manually annotated