136,264 research outputs found
Probing transverse momentum dependent gluon distribution functions from hadronic quarkonium pair production
The inclusive hadronic production of ( or ) pair is
proposed to extract the transverse momentum dependent(TMD) gluon distribution
functions. We use nonrelativistic QCD(NRQCD) for the production of .
Under nonrelativistic limit TMD factorization for this process is assumed to
make a lowest order calculation. For unpolarized initial hadrons, unpolarized
and linearly polarized gluon distributions can be extracted by studying
different angular distributions.Comment: 7 pages, 3 figures, 1 tabl
Automatic Image Segmentation by Dynamic Region Merging
This paper addresses the automatic image segmentation problem in a region
merging style. With an initially over-segmented image, in which the many
regions (or super-pixels) with homogeneous color are detected, image
segmentation is performed by iteratively merging the regions according to a
statistical test. There are two essential issues in a region merging algorithm:
order of merging and the stopping criterion. In the proposed algorithm, these
two issues are solved by a novel predicate, which is defined by the sequential
probability ratio test (SPRT) and the maximum likelihood criterion. Starting
from an over-segmented image, neighboring regions are progressively merged if
there is an evidence for merging according to this predicate. We show that the
merging order follows the principle of dynamic programming. This formulates
image segmentation as an inference problem, where the final segmentation is
established based on the observed image. We also prove that the produced
segmentation satisfies certain global properties. In addition, a faster
algorithm is developed to accelerate the region merging process, which
maintains a nearest neighbor graph in each iteration. Experiments on real
natural images are conducted to demonstrate the performance of the proposed
dynamic region merging algorithm.Comment: 28 pages. This paper is under review in IEEE TI
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