A novel object tracking algorithm based on compressed sensing and entropy of information

Acknowledgments This research is supported by (1) the Ph.D. Programs Foundation of Ministry of Education of China under Grant no. 20120061110045, (2) the Science and Technology Development Projects of Jilin Province of China under Grant no. 20150204007G X, and (3) the Key Laboratory for Symbol Computation and Knowledge Engineering of the National Education Ministry of China.Peer reviewedPublisher PD

Studies in ambient intelligent lighting

The revolution in lighting we are arguably experiencing is led by technical developments in the area of solid state lighting technology. The improved lifetime, efficiency and environmentally friendly raw materials make LEDs the main contender for the light source of the future. The core of the change is, however, not in the basic technology, but in the way users interact with it and the way the quality of the produced effect on the environment is judged. With the new found freedom the users can switch their focus from the confines of the technology to the expression of their needs, regardless of the details of the lighting system. Identifying the user needs, creating an effective language to communicate them to the system, and translating them to control signals that fulfill them, as well as defining the means to measure the quality of the produced result are the topic of study of a new multidisciplinary area of study, Ambient Intelligent Lighting. This thesis describes a series of studies in the field of Ambient Intelligent Lighting, divided in two parts. The first part of the thesis demonstrates how, by adopting a user centric design philosophy, the traditional control paradigms can be superseded by novel, so-called effect driven controls. Chapter 3 describes an algorithm that, using statistical methods and image processing, generates a set of colors based on a term or set of terms. The algorithm uses Internet image search engines (Google Images, Flickr) to acquire a set of images that represent a term and subsequently extracts representative colors from the set. Additionally, an estimate of the quality of the extracted set of colors is computed. Based on the algorithm, a system that automatically enriches music with lyrics based images and lighting was built and is described. Chapter 4 proposes a novel effect driven control algorithm, enabling users easy, natural and system agnostic means to create a spatial light distribution. By using an emerging technology, visible light communication, and an intuitive effect definition, a real time interactive light design system was developed. Usability studies on a virtual prototype of the system demonstrated the perceived ease of use and increased efficiency of an effect driven approach. In chapter 5, using stochastic models, natural temporal light transitions are modeled and reproduced. Based on an example video of a natural light effect, a Markov model of the transitions between colors of a single light source representing the effect is learned. The model is a compact, easy to reproduce, and as the user studies show, recognizable representation of the original light effect. The second part of the thesis studies the perceived quality of one of the unique capabilities of LEDs, chromatic temporal transitions. Using psychophysical methods, existing spatial models of human color vision were found to be unsuitable for predicting the visibility of temporal artifacts caused by the digital controls. The chapters in this part demonstrate new perceptual effects and make the first steps towards building a temporal model of human color vision. In chapter 6 the perception of smoothness of digital light transitions is studied. The studies presented demonstrate the dependence of the visibility of digital steps in a temporal transition on the frequency of change, chromaticity, intensity and direction of change of the transition. Furthermore, a clear link between the visibility of digital steps and flicker visibility is demonstrated. Finally, a new, exponential law for the dependence of the threshold speed of smooth transitions on the changing frequency is hypothesized and proven in subsequent experiments. Chapter 7 studies the discrimination and preference of different color transitions between two colors. Due to memory effects, the discrimination threshold for complete transitions was shown to be larger than the discrimination threshold for two single colors. Two linear transitions in different color spaces were shown to be significantly preferred over a set of other, curved, transitions. Chapter 8 studies chromatic and achromatic flicker visibility in the periphery. A complex change of both the absolute visibility thresholds for different frequencies, as well as the critical flicker frequency is observed. Finally, an increase in the absolute visibility thresholds caused by an addition of a mental task in central vision is demonstrated

The Carnegie Supernova Project: The Low-Redshift Survey

Supernovae are essential to understanding the chemical evolution of the Universe. Type Ia supernovae also provide the most powerful observational tool currently available for studying the expansion history of the Universe and the nature of dark energy. Our basic knowledge of supernovae comes from the study of their photometric and spectroscopic properties. However, the presently available data sets of optical and near-infrared light curves of supernovae are rather small and/or heterogeneous, and employ photometric systems that are poorly characterized. Similarly, there are relatively few supernovae whose spectral evolution has been well sampled, both in wavelength and phase, with precise spectrophotometric observations. The low-redshift portion of the Carnegie Supernova Project (CSP) seeks to remedy this situation by providing photometry and spectrophotometry of a large sample of supernovae taken on telescope/filter/detector systems that are well understood and well characterized. During a five-year program which began in September 2004, we expect to obtain high-precision u'g'r'i'BVYJHKs light curves and optical spectrophotometry for about 250 supernovae of all types. In this paper we provide a detailed description of the CSP survey observing and data reduction methodology. In addition, we present preliminary photometry and spectra obtained for a few representative supernovae during the first observing campaign.Comment: 45 pages, 13 figures, 3 tables, accepted by PAS

Fair comparison of skin detection approaches on publicly available datasets

Skin detection is the process of discriminating skin and non-skin regions in a digital image and it is widely used in several applications ranging from hand gesture analysis to track body parts and face detection. Skin detection is a challenging problem which has drawn extensive attention from the research community, nevertheless a fair comparison among approaches is very difficult due to the lack of a common benchmark and a unified testing protocol. In this work, we investigate the most recent researches in this field and we propose a fair comparison among approaches using several different datasets. The major contributions of this work are an exhaustive literature review of skin color detection approaches, a framework to evaluate and combine different skin detector approaches, whose source code is made freely available for future research, and an extensive experimental comparison among several recent methods which have also been used to define an ensemble that works well in many different problems. Experiments are carried out in 10 different datasets including more than 10000 labelled images: experimental results confirm that the best method here proposed obtains a very good performance with respect to other stand-alone approaches, without requiring ad hoc parameter tuning. A MATLAB version of the framework for testing and of the methods proposed in this paper will be freely available from https://github.com/LorisNann