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Visual tracking in wide area motion imagery (WAMI) is an important problem in security related tasks. The extremely low frame rate and the large camera motion in such videos, however, introduce challenging constraints that distinguish the task from traditional image tracking. In this study we evaluate the performance of several state-of-the-art visual(More)
In this paper, we study a novel problem of classifying covert photos, whose acquisition processes are intentionally concealed from the subjects being photographed. Covert photos are often privacy invasive and, if distributed over Internet, can cause serious consequences. Automatic identification of such photos, therefore, serves as an important initial step(More)
The advances in image acquisition techniques make recording images never easier and brings a great convenience to our daily life. It raises at the same time the issue of privacy protection in the photographs. One particular problem addressed in this paper is about covert photographs, which are taken secretly and often violate the subjects' willingness. We(More)
Classifying scenes (such as mountains, forests) is not an easy task owing to their variability, ambiguity, and the wide range of illumination and scale conditions that may apply. Bag of features (BoF) model have achieved impressive performances in many famous databases(such as the 15 scene dataset). A main drawback of the BoF model is it disregards all(More)
In this paper, a Blur Resilient target Tracking algorithm (BReT) is developed by modeling target appearance with a groupwise sparse approximation over a template set. Since blur templates of different directions are added to the template set to accommodate motion blur, there is a natural group structure among the templates. In order to enforce the solution(More)
We propose a novel local feature descriptor named Enhanced Point Descriptor (referred to as EPD) for dense stereo matching applications. The existing local feature descriptors, e.g., SIFT and SURF, can only be used to represent sparse image extreme points which make stereo matching sparsely. We design EPDs to represent common image points. To generate an(More)
We are focused on how to describe a common image point distinctively, make its descriptor concise and invariant to general image transformations. We use neighborhood pixel characteristics, including HSV color space, Gaussian-weighted gradient magnitudes and orientations, sampled in specific window around interest point to enhance the description. The(More)
The ambiguity function was employed as a merit function to design an optical system with a high depth of focus. The ambiguity function with the desired enlarged-depth-of-focus characteristics was obtained by using a properly designed joint filter to modify the ambiguity function of the original pupil in the phase-space domain. From the viewpoint of the(More)