Mark J. T. Smith

Exact reconstruction techniques for tree-structured subband coders

In recent years, tree-structured analysis/reconstruction systems have been extensively studied for use in subband coders for speech. In such systems, it is imperative that the individual channel signals be decimated in such a way that the number of samples coded and transmitted do not exceed the number of samples in the original speech signal. Under this constraint, the systems presented in the past have sought to remove the aliasing distortion while minimizing the overall analysis/reconstruction distortion. In this paper, it is shown that it is possible to design tree-structured analysis/reconstruction systems which meet the sampling rate condition and which result in exact reconstruction of the input signal. The conditions for exact reconstruction are developed and presented. Furthermore, it is shown that these conditions are not overly restrictive and high-quality frequency division may be performed in the analysis section. A filter design procedure is presented which allows high-quality filters to be easily designed.

Time-domain filter bank analysis: a new design theory

The authors present a new time-domain approach for the analysis and design of a broad class of general analysis/synthesis systems based on M-band filter banks. They derive a set of time-domain conditions for reconstruction which can be used directly in a filter bank design procedure. The general and unrestricted nature of this framework allows for the design of many useful banks. In addition to the complete derivation of the time-domain conditions, they also describe the associated filter bank design procedure and a number of design examples are included. >

Low delay FIR filter banks: design and evaluation

The subject of this paper is the design of low and minimum delay, exact reconstruction analysis-synthesis systems based on filter banks. It presents a time domain approach to the problem of designing FIR filter banks with adjustable reconstruction delays. It is shown that using a time domain formulation for the analysis-synthesis systems, the system delay can be considered to be relatively independent of the length of the analysis and synthesis filters. After a summary of the time domain analysis and design framework, the design of low and minimum delay systems is considered in detail. Several design examples are provided in the paper to demonstrate the performance of the design algorithm. >

A Novel Lane Detection System With Efficient Ground Truth Generation

A new night-time lane detection system and its accompanying framework are presented in this paper. The accompanying framework consists of an automated ground truth process and systematic storage of captured videos that will be used for training and testing. The proposed Advanced Lane Detector 2.0 (ALD 2.0) is an improvement over the ALD 1.0 or Layered Approach with integration of pixel remapping, outlier removal, and prediction with tracking. Additionally, a novel procedure to generate the ground truth data for lane marker locations is also proposed. The procedure consists of an original process called time slicing, which provides the user with unique visualization of the captured video and enables quick generation of ground truth information. Finally, the setup and implementation of a database hosting lane detection videos and standardized data sets for testing are also described. The ALD 2.0 is evaluated by means of the user-created annotations accompanying the videos. Finally, the planned improvements and remaining work are addressed.

New framework for modulated perfect reconstruction filter banks

A new formulation for the analysis and design of modulated filter banks is introduced. The formulation provides a broad range of design flexibility within a compact framework and allows for the design of a variety of computationally efficient modulated filter banks with different numbers of bands and virtually arbitrary lengths. A unique feature of the formulation is that it provides explicit control of the input-to-output system delay in conjunction with perfect reconstruction. Design examples are given to illustrate the methodology.

A new algorithm for efficient low delay filter bank design

Historically, exact reconstruction FIR filter banks have had system delays of L-1, where L is the length of the analysis and synthesis filters. Recently it was shown that the system delay could be made less than L-1, which is attractive in applications like speech coding where excessive delays are annoying. In this paper, a formulation and new design algorithm are introduced for two-band low-delay filter banks. The formulation is related to that of two-band lattice filter banks and provides a broad range of design flexibility within a compact framework. Both exact reconstruction and specified system delay are guaranteed by the structure of the framework.

Short Wavelength Infrared Face Recognition for Personalization

The paper describes an application of practical technologies to implement a low cost, consumer grade, single chip biometric system based on face recognition using infra-red imaging. The paper presents a system that consists of three stages that contribute in the face detection and recognition process. Each stage is explained with its individual contribution alongside results of tests performed for that stage. The system shows a high recognition rate when full frontal face images are led to the system. The paper further discusses the application based approach in the automotive world with plans for further study. Recognition rates of the overall system are also presented.

Circuit implementation of a 2-D gradient source localizer [temperature localization]

Gradient field localization, such as chemical and heat source location, is a complex problem, yet few designs have been proposed. Examples are locating fires, thermal leaks in insulation, explosive vapors, illegal substances, and chemical leaks. In this paper, we propose one 4 sensor stationary array to localize the direction-of-arrival (DOA) of a temperature source and model the approach on our previous biologically-inspired array processing technique. Several variants of the algorithm are shown, and with each degree of sophistication, it significantly reduces the DOA variance caused by noisy measurement conditions. Next, a clean 4/8-sensor version of the array was constructed, and it is shown that sensor cooperation improves the adaptation in diffusive, turbulent, and noisy environments.

Detecting lane markers in a complex environment using a single camera approach

Lane detection is an important application of driver assistance. In this paper, a new technique for detecting lane markers that is able to cope with many complex conditions is presented. Some of these conditions include dynamic illumination, scattered shadows, and the presence of neighboring vehicles to name a few. The input image is first pre-processed with a perspective removal transformation followed by a color space conversion. Then, the core elements of the proposed technique consisting of template matching, lane region merging, elliptical projections, and parametric tracking are explained. A formal error metric used in performance evaluation is also introduced. Finally, quantitative analyses show that the developed system performs well in real-world driving conditions with variations in illumination, traffic, and road surface quality.