Robust object detection using a Radial Reach Filter (RRF)

We propose a new method for background modeling. Our method is based on the two complementary approaches. One uses the probability density function(PDF) to approximate background model. The PDF is estimated non-parametrically by using Parzen density estimation. And foreground object is detected based on the estimated PDF. The other method is based on the evaluation of the local texture at pixel-level resolution while reducing the effects of variations in lighting. Fusing their approach realize robust object detection under varying illumination. Several experiments show the effectiveness of our approach.

An understanding of light and its interaction with matter is essential to produce images. As the modeling of light sources, light transport and light reflection improves, it becomes possible to render images with increasing realism. The central motivation behind this thesis is to improve realism in computer graphics images by more accurate local shading models and to assist the user to obtain the desired lighting effects with these more complex models. The first part of the thesis addresses the problem of rendering surfaces illuminated by extended (linear and area) light sources. To compute the light reflected by a surface element in a given direction, one needs to determine the unoccluded regions (shadowing) of each light source and then to compute the light reflection (shading) from each of these regions. Traditionally, point light sources are distributed on the lights to approximate both the shadowing and the shading. Instead, an efficient analytical solution is developed for the shading. Shadowing from extended light sources is a fairly expensive process. To give some insights on the complexity of computing shadows, some properties of shadows and algorithms are presented. To reduce the cost of computing shadows from linear light sources, two acceleration schemes, extended from ray tracing, are introduced and evaluated. The second part of this thesis addresses the problem of achieving a desired shading effect by building up systems of constraints. This approach is called inverse shading. It allows a user to obtain a desired lighting effect by interacting directly with the scene model. An interactive modeling system has been built to study the introduction of rendering issues into the modeling process itself. Two rendering aspects are considered: shading and shadows. By specifying a highlight position and size, the unique direction of a directional light source as well as the surface glossiness are determined. Interactively moving this highlight on the surface redefines the light direction while changing its size redefines the surface glossiness. By manipulating shadow volumes (the volume within which a particular light cannot be completely seen), the light source definition and position can be modified. By assigning colours to various points in a 3D scene, information about the colour of a surface as well as other surface characteristics can be deduced. This relatively new concept of defining the causes by manipulating the effects is expected to have a major impact on the design of future computer graphics modeling systems. It begins a new family of tools for the design of more intuitive user interfaces.

This paper examines the epistemological model based upon the Enlightenment paradigm that underlies Modern Western thought and discusses other forms of writing and production of knowledge. Based on the the work of Michel Foucault, Walter Benjamin, Giorgio Agamben and others, we consider the production of knowledge in darkness. We start out with an evaluation of the effects of an epistemology of light and the potential of thought in the absence of light. We present an analysis of the relationship of that epistemology with forms of organization and urban lighting, as well as the production of invisible subjectivities. In a writing exercise conducted in a zone of shadows, we relate a story which binds the production of light and shadow and their productive power within contemporary urban society. Finally, this study affirms the power of shadows and the need to devise strategies that allow us to write in or with darkness and with those invisible subjectivities which inhabit it.Keywords: epistemology, writing, cities, subjectivities, powerResumoNesse artigo refletimos sobre o modelo epistemológico pautado na ideia de luzes constituinte do pensamento Ocidental Moderno, discutindo outras formas de escrever e produzir conhecimento. A partir de autores como Michel Foucault, Walter Benjamin e Giorgio Agamben, propomos uma reflexão sobre a produção do conhecimento no escuro. Iniciamos abordando os efeitos da epistemologia da luminosidade e a potência de se pensar nas sombras. Em seguida, analisamos a relação dessa epistemologia com as formas de organização e iluminação das cidades e a produção de subjetividades invisíveis. Em um exercício de escrita a partir de uma zona sombria, trazemos uma história que amarra a produção de luzes e sombras e seu poder produtivo na sociedade urbana contemporânea. Ao final, afirmamos a potência das sombras e a necessidade de construção de estratégias que nos permitam escrever no e com o escuro e com aquelas subjetividades invisíveis que o habitam.Palavras-chave: epistemologia, escrita, cidade, subjetividades, potência AbstractThis paper examines the epistemological model based upon the Enlightenment paradigm that underlies Modern Western thought and discusses other forms of writing and production of knowledge. Based on the the work of Michel Foucault, Walter Benjamin, Giorgio Agamben and others, we consider the production of knowledge in darkness. We start out with an evaluation of the effects of an epistemology of light and the potential of thought in the absence of light. We present an analysis of the relationship of that epistemology with forms of organization and urban lighting, as well as the production of invisible subjectivities. In a writing exercise conducted in a zone of shadows, we relate a story which binds the production of light and shadow and their productive power within contemporary urban society. Finally, this study affirms the power of shadows and the need to devise strategies that allow us to write in or with darkness and with those invisible subjectivities which inhabit it.Keywords: epistemology, writing, cities, subjectivities, powerAbstractThis paper examines the epistemological model based upon the Enlightenment paradigm that underlies Modern Western thought and discusses other forms of writing and production of knowledge. Based on the the work of Michel Foucault, Walter Benjamin, Giorgio Agamben and others, we consider the production of knowledge in darkness. We start out with an evaluation of the effects of an epistemology of light and the potential of thought in the absence of light. We present an analysis of the relationship of that epistemology with forms of organization and urban lighting, as well as the production of invisible subjectivities. In a writing exercise conducted in a zone of shadows, we relate a story which binds the production of light and shadow and their productive power within contemporary urban society. Finally, this study affirms the power of shadows and the need to devise strategies that allow us to write in or with darkness and with those invisible subjectivities which inhabit it.Keywords: epistemology, writing, cities, subjectivities, power

Digital image processing forms core research area with in computer science disciplines. Rapid growth of image processing technologies has been used digital images more and more prominent in our daily life. Brightness preservation is a technique of improving the image brightness so that the limitations contained in these images is used for various applications in a better way. The contrast enhancement techniques capable to clean up the unwanted noises and enhance the image’s brightness and contrast. In this project aimed to recover the original form of the image and video taken without presence of proper lighting effect. The previous techniques used are histogram equalization, gamma correction for contrast and brightness enhancement in image, here the improved version to overcome the noise and contrast enhancement by the FFT, Bi-log transformation and NTSC are used for both image and video quality improvement.

A framework is suggested to segment the foreground in image sequences using background subtraction based on the reconstructed background image for each frame. First, the consecutive frames are taken as inputs for a motion estimation algorithm to calculate the motion vector between frames. Second, an incomplete background image can be achieved by cutting moving parts from origin images. Then, all the incomplete background images from the same sequence can be used to model the background by probabilistic principle component analysis with missing data. The background image can be estimated for each frame. Finally, a simple background subtraction can segment the foreground. The effectiveness of our method is demonstrated in different illumination conditions and compared to the commonly used Gaussian mixture models method.

Smart CCTV (Closed-Circuit Television) technology has increasingly been developed in the last few years to judge the situation and notify the administrator or take immediate action for security and surveillance reasons. Currently the methods to detect object motion typically include the Frame Difference Method (FDM) which can detect moving objects and the Background Subtraction Method (BSM) which is able to detect motionless objects. Those results can be obtained only if there were some background images ready in advance. The Adaptive Background Subtraction Method (ABSM) also could not recognize an object very well if there are rapid scene changes or an object does not move relatively for a long time. To resolve such a problem, in this research, a filmed image has been divided into the regular sized blocks and then, only the necessary parts of the previous frame image are updated in real-time and a background image was generated so that it is insensible to surrounding environment changes such as object motion, noise or light variations. We proposed a novel moving object detection method which showed high performance with regard to the MSE (Mean Squared Error) and the accuracy of detecting the moving object contours compared to other existing methods. We also evaluated quantitatively the detectability for a moving object region by quickly creating a background image even if it is difficult to shoot a background image or we do not have the baseline image prepared in advance. The proposed method could be used for cases that any background image does not exist or hard to be generated. It is also good for observation of many places at the same time with only a single CCTV system since it is especially robust to abrupt scene changes.

Detecting moving objects by using an adaptive background model is a critical component for many vision-based applications. In this paper, we propose a novel background modeling algorithm for traffic video surveillance based on objects dynamicity. Our algorithm is based on the definition of background as a set of static objects and on the observation that a static object is a set of pixels having the same appearance in long time interval. The normalized RGB color is used to describe the appearance under change lighting conditions, and a binary label is introduced to capture the dynamicity of objects over time. Finally, the cardinality function, calculated in each continued time period, is used to select persistent appearance corresponding to background objects. An update formula is proposed to reconstruct background model periodically based on current frame and last background image. Experimental results from several video sequences validate the effectiveness of the proposed algorithm

The ray tracing algorithmis well-known for its ability to generate high-quality images and its flexibility to support advanced rendering and lighting effects. Interactive ray tracing has been shown to work well on clusters of PCs and supercomputers but direct hardware support for ray tracing has been difficult to implement.In this paper, we present a new, scalable, modular, and highly efficient hardware architecture for real-time ray tracing. It achieves high performance with extremely low memory bandwidth requirements by efficiently tracing bundles of rays. The architecture is easily configurable to support a variety of workloads. For OpenGL-like scenes our architecture offers performance comparable to state-of-the-artrasterization chips. In addition, it supports all the usual ray tracing features including exact shadows, reflections, and refraction and is capable of efficiently handling complex scenes with millions of triangles. The architecture and its performance in different configurations is analyzed based on cycle-accurate simulations.

Computer-generated imagery has become a central point in large and quickly growing areas such as computer animation, visual effects, architecture, high-quality visualization, and product design. A common requirement to all these areas is the efficient simulation of light transport from the light source to the sensor for image synthesis. This is a challenging task, as light can travel along all kinds of paths, and some paths are hard to find when computing the result numerically. The process of light propagation in a virtual scene is described by a path integral equation. This path integral is defined over the path space, the space of all possible light paths, on which photons travel from a light source to a virtual sensor. Monte Carlo approaches are employed for computing the path integral, where paths are stochastically generated (sampled). The integration, to compute an image of a virtual scene, in this space is challenging because of the mathematical properties of the integrand. In addition, the demand for both image quality and quantity requires shorter image rendering times, while imposing higher scene complexity at the same time. We provide several solutions to the problems arising with difficult light paths, especially these involving specular and glossy materials, as well as improve the rendering convergence with difficult illumination effects. Some physical phenomena, such as perfectly specular reflection, cause singularities in the path integral, and thus are hard or even impossible to sample. We propose an approach to adaptively smooth difficult components of light transport, which makes them samplable while still ensuring convergence to the exact solution. It uses regularization for paths which cannot be sampled in an unbiased way. To introduce as little bias as possible, we selectively regularize individual interactions along paths, and also derive the regularization consistency conditions. Additionally, in order to control the bias introduced by kernel smoothing, which is another means to sample complex light transport, we developed an adaptive bandwidth selection method. We have also analyzed the convergence rate for kernel smoothing methods in light transport. On the other hand, even not perfectly specular, i.e., glossy, materials can be as difficult to sample. We propose a new way for representing light paths for more efficient exploration of the path space. Based on this, we propose a new mutation strategy, to be used with Markov chain Monte Carlo methods such as Metropolis light transport, which is well-suited for all configurations of surface scattering. A different yet related problem is the creation of virtual scenes with photorealistic lighting. It can be challenging because it often requires interactive feedback and edits to the scene that are propagated consistently. To alleviate this process, we propose a set of visualization and manipulation tools, which allow the designers to grasp virtual illumination and to alter the physical laws of light transport for convenient illumination setup and analysis, as well as for achieving artistic goals.

We investigated in three separate experiments the perceived achromatic colour, transparency, and phenomenal attributes of concentric-circle neon-brightness-spreading displays. Stimuli were obtained by varying the luminances of the outer arc (OA) and inner arc (IA) of circle, while keeping the background luminance constant. In the first experiment, observers modified the luminance of an adjustable region to match the achromatic colour of the central area of the displays; additional adjustments were performed on sets of control figures without IA (subjective figures) and without OA. In the second experiment, observers judged the transparency of the central area of the displays using either numerical ratings or dichotomous judgments. In the third experiment, they used four possible categories (light, shadow, filter, opaque) to describe the appearance of the displays. Only displays with intermediate background luminance were perceived as non-transparent. Displays with intermediate IA luminance were seen as transparent filters, whereas those with intermediate OA luminance were categorised as either lights or shadows, depending on luminance polarity. Adjustment data show that a simple contrast rule accounts well for induction effects in OA-only and IA-only figures. Data concerning complete figures show an interaction between OA and IA luminances in determining the percept; in particular, the contrast effect of OA luminance appears modulated by IA luminance in a nonmonotonic fashion. We discuss the implications of these findings on our current understanding of the mechanisms of neon brightness and colour spreading.

Real-time shadowed crowds, especially under locally lit environments, po se several distinct challenges. Current solutions for crowds are either very simplistic for multiple lights or only handle a single directional light with shadows. This work focuses on bringing hundreds of local lights with high fidelity shad ows for crowds into the real-time domain. Each light is given the ability to cast shadows for all objects (dynamic and static ) within the scene, and all the levels of detail used for representing the crowds correctly interact with the lighting conditions. In this paper we introduce depth augmented billboards for crowds, to allow for improved quality under lo cal lights, including self-shadowing. Through use of the GPU fragment programs; this extension is entirely imple mented on the graphics card for minimal performance impact.

With the rapid urbanization, problems caused by heat-island effect have become more and more serious. It is necessary to make rapid and effective monitoring of the distribution of heat islands in cities. In this paper, the Landsat7 ETM~+ image of Nanjing was investigated as an example. A correlation model was built between ground temperature and image brightness of TM6, and in this way, the distribution of temperatures in Nanjing was obtained. The urban vegetation can be classified into forest, interspersed tree and herbaceous plant based on the NDVI value. At the same time, the other ground objects can be classified by supervised classification. In addition, the authors probed into the correlation coefficient between the ground covers and the temperature distribution from the angle of fragmentation degree. It can be concluded that different fragmentation degrees of urban greening exert different effects on the temperature of ground surface.

Helical CT was used on a trial basis for secondary screening of lung cancer, and its clinical usefulness is discussed in this report. The subjects 157 patients with abnormal shadows on plain chest X-ray images acquired between November 1993 and August 1994. Imaging parameters used for screening CT were as follows: 50 mA, 120 kV, a couch-top movement speed of 20 mm/s, and a beam width of 10 mm. The entire lung field was scanned during a single breath-hold. Reconstructed images were generated at 10-mm intervals by the 180 degree interpolation method, and films were produced. Images of the entire lung field were made during a single breath-hold in all patients. Abnormal shadows were detected in 73 of 157 patients by screening CT. These 73 patients included 14 with lung cancer, 53 with benign lesions, one under observation, and five others. The average diameter of the tumors was 11.1 mm. The lung cancers detected all arose in the periphery, and were classified into stage I (10 paeitents), stage IIIA (3 patients), and stage IV with bone metastases (1 patient). Lung cancers in clinical stage I (3 patients) and stage IV (1 patient) were difficult to see on plain chest X-ray films. We conclude that screening CT is useful for early diagnosis of lung cancer because the entire lung field can be imaged during a single breath-hold. Therefore, helical CT can be expected to be useful in screening for lung cancer.

Publication in the conference proceedings of EUSIPCO, Trieste, Italy, 1996

Artificial light decreases the amplitude of daily rhythms in human lifestyle principally by permitting activity and food intake to occur during hours of darkness, and allowing day-time activity to occur in dim light, indoors. Endogenous circadian timing mechanisms that oscillate with a period of 24 h have evolved to ensure physiology is synchronized with the daily variations in light, food, and social cues of the environment. Artificial light affects the synchronization between these oscillators, and metabolic disruption may be one consequence of this. By dampening the amplitude of environmental timing cues and disrupting circadian rhythmicity, artificial lighting might initiate metabolic disruption and contribute to the association between global urbanization and obesity. The aim of this review is to explore the historical, physiological, and epidemiological relationships between artificial light and circadian and metabolic dysfunction.