Jan Borgosz

An improved variogram analysis of the maximum expected disparity in stereo images

This paper concerns the method of estimation of one of the initial parameters for stereo image processing - the maximum expected disparity value. An automatic assessment of this parameter would benefit in improvement of automation and performance of stereo methods. The authors have developed an improved version of the heuristic method of estimation of the maximum disparity value for real stereo images. It is based on statistical analysis of the spatial correlation between stereo images - the so called image variograms, used so far only to single images and extended to the processing of stereo views by authors of this paper.

Dual-band Capacitive Feed Antenna for Nonlinear Junction Detection Device

The paper presents an antenna design for use in a nonlinear junction detection device. To achieve wide bandwidth a capacitive feed technique is used in which small probe feed elements are coupled to the radiating patch. In order to minimize the overall antenna size both receiving and transmitting antenna elements have been integrated into one dual-band structure having two separate excitation ports. High isolation between ports is achieved to avoid direct interferences between a transmitter and a receiver. Results of theoretical analysis are presented agree well with the experimental ones.

A Comparative Study of Performance and Implementation of Some Area-Based Stereo Algorithms

The paper presents a comparison of a practical implementation of some area-based stereo algorithms. There are many stereo algorithms known that employ area based processing for matching of two or more images. However, much less information is available on practical implementations and applications of such methods, as well as their advantages and limitation. The work has been done to fill this gap and facilitate choice of the right stereo algorithm for machine vision applications, often using off-the-shelf cameras

Gradient Based Dense Stereo Matching

This paper contains a study on image matching techniques based on image gradients. Gradients of the intensity signal play the very important role in the human visual system and also in computer vision. Since the onset of computer image processing, features, in a form of gradients, have been used for matching. However, the second part of a matching process is a choice of the matching criterion, called a comparison measure. The main contribution of this paper is a survey of the gradient comparison measures, ended with a proposition of the two new measures that we believe are more appropriate for gradient stereo matching. The paper presents results of many experiments performed to validate our methods.

Design of electromagnetically coupled corner-series-fed antenna arrays with the application for 24 GHz doppler sensors

This paper presents a comprehensive analysis and design of electromagnetically coupled corner-series-fed antenna arrays. A theoretical modeling approach is used to estimate the required coupling level and the amplitude distribution across the radiating elements. The 4x1 antenna array has been designed with the use of Arlon copper- cladded foam, manufactured and measured. The obtained results are in a good agreement with the calculated ones and confirm the usefulness of the proposed design method. The designed antenna is suitable for operation in 24 GHz motion Doppler sensors; moreover, it can be used as a subarray of larger antenna arrays.

Fuzzy Nonparametric Measures for Image Matching

Many correlation measures have been already proposed for image matching. The special group with quite different statistical properties constitute the nonparametric measures. Their virtue in the task of image matching lies mostly in the known distribution function and resistance against local image fluctuations and outliers. In this paper the fuzzy enhancement of the nonparametric measures is proposed. It allows for better representation of the local relations among image pixels. The presented concepts are underpinned by many experiments which results are also provided and discussed.

Maximum disparity threshold estimation for stereo imaging systems via variogram analysis

Estimation of the highest disparity value is very important for proper operation of any stereo matching algorithm. Choice of a too big or too small disparity range may cause severe errors in an output disparity map. A guess of this parameter by human is the method which is used very often during experiments, however it is not suitable in real time or autonomous vision systems. In the same way, a usage of the constant disparity range gives often poor results. The paper describes a innovative method of the automatic estimation of a maximum disparity for the real time stereo imaging systems. After short review of the most popular methods of the maximum disparity estimation, we present our method based on the variogram analysis. Finally the experimental results for the real images are also presented.

A Proposal of Jitter Analysis Based on a Wavelet Transform

The paper puts forth a proposal for a new jitter measurement method based on a wavelet transform usage. There are many problems associated with the generation jitter free reference clock for measurements. The proposed method does not need a reference clock which is its main advantage over known methods that rely on reference clock usage. Additionally, presented wavelet transform applied to the jitter signals allows for more detailed analysis than offered by other methods. Comparison of classic and wavelet approach is presented. Problems like wavelet function type, order and post processing methods are also indicated.

Multilayer surface-mount 3dB directional coupler for application in balanced modulators

A 3-dB coupled-line surface-mount directional coupler has been designed. As a base substrate a common FR4 laminate has been used. Three-strip coupled-line configuration of the coupled lines has been chosen in order to achieve good return loses and high isolation of the designed coupler. The designed coupler has been used in the development of balanced modulators. Measurement results of the designed directional coupler and modulators are shown.

Control Messaging Channel for Distributed Computer Systems

The paper addresses the problem of communication among modules of the distributed computer systems. Such systems can be characterized as a connection of many self-contained sub-modules which are either governed by a distinguished unit or are connected in a peer-to-peer fashion. At the same time it is required that the modules communicate reliably with each other without excessive delays and transmission errors. However, very often, due to the nature of embedded systems, these requirements are not matched by the computational power of the system participants. In this paper we present a novel protocol especially designed and implemented for embedded systems. The main advantage of the presented solution consists in the properly balanced proportions between transmission reliability and algorithm complexity. The latter allows implementations starting from the simplest, even 8-bit, microprocessor platforms. There is also no constraint on the used lowest-level protocol layers, electrically or optically connecting components of a system. The paper provides also details of a practical realization in a form of class hierarchies and code.