Hierarchical Template Matching for Robust Visual Tracking with Severe Occlusions

To tackle the problem of severe occlusions in visual tracking, we propose a hierarchical template-matching method based on a layered appearance model. This model integrates holistic- and part-region matching in order to locate an object in a coarse-to-fine manner. Furthermore, in order to reduce ambiguity in object localization, only the discriminative parts of an object＇ s appearance template are chosen for similarity computing with respect to their cornerness measurements. The similarity between parts is computed in a layer-wise manner, and from this, occlusions can be evaluated. When the object is partly occluded, it can be located accurately by matching candidate regions with the appearance template. When it is completely occluded, its location can be predicted from its historical motion information using a Kalman filter. The proposed tracker is tested on several practical image sequences, and the experimental results show that it can consistently provide accurate object location for stable tracking, even for severe occlusions.

Silver hierarchical structures grown on microstructured silicon in chip for microfluidic integrated catalyst and SERS detector

In this Letter, silver（Ag） hierarchical nanostructures grown on black silicon（BS） are used as the catalyst and a surface-enhanced Raman scattering（SERS） detector integrated in a microfluid. The BS is fabricated via femtosecond laser ablation in an atmosphere of sulfur hexafluoride, and then hydrogenated with hydrofluoric acid. As formed, the BS substrate directly acts as a reducing template to grow silver hierarchical nano-structures.Particularly, Ag-BS composite micro/nano-structures can be in-situ constructed in silicon-based microchannels.These structures simultaneously serve as integrated catalytic reactors and a SERS substrate for sensing. The sensitivity is tested to be as low as 10-8mol∕L using Rhodamine 6G.

Versatile nanosphere lithography technique combining multiple-exposure nanosphere lens lithography and nanosphere template lithography

A versatile nanosphere composite lithography（NSCL） combining both the advantages of multiple-exposure nanosphere lens lithography（MENSLL） and nanosphere template lithography（NSTL） is demonstrated. By well controlling the development, washing and the drying processes, the nanosphere monolayer can be well retained on the substrate after developing and washing. Thus the NSTL can be performed based on MENSLL to fabricate nanoring, nanocrescent and hierarchical multiple structures. The pattern size and the shape can be systemically tuned by shrinking nanospheres by using dry etching and adjusting the tilted angle. It is a natural nanopattern alignment process and possesses a great potential in the scope of nano-science due to its low cost,simplicity, and versatility for variuos nano-fabrications.