The paper presents basic concepts of augmented reality applications and challenges in building them in the web. We describe the technical and algorithmic stack required to develop, implement and deploy the augmented reality application. Theoretical concepts behind marker detection and tracking are discussed. Two different pipelines are implemented: server-based with algorithms execution in the cloud and completely front-end solution that runs on a user device.
Synthetic aperture radar is a very popular and widely used instrument for various remote sensing tasks. One of the most challenging problems is to obtain high-quality images in the case of unstable flight conditions. In the paper the problem of full platform motion compensation is discussed. A particular attention is given to the analysis of moving targets. Algorithm for estimation of moving target parameters is developed. Experimental results with real data are illustrated.
Augmented Reality (AR) is one of the most popular and challenging fields in computer vision research. It allows to supplement real world with some kind of digital content, for example, virtual 3D objects. The key feature of Augment Reality in comparison to other image processing tools is that virtual objects are moved and rotated in 3D coordinates instead of 2D image coordinates.
High-resolution imaging with an airborne synthetic aperture radar (SAR) calls for precise trajectory measurements that can hardly be achieved with common navigation systems. In this paper, an efficient method called the local-quadratic map-drift autofocus is developed for the estimation of residual (uncompensated) motion errors directly from the received radar data. The map-drift autofocus is applied locally on short time intervals to estimate the cross-track components of the aircraft acceleration.
The idea for automatic extraction of the moving target parameters using single-antenna synthetic aperture radar is proposed. The displacements of the target are estimated from the sequence of the single-look SAR images using the Lucas-Kanade optical flow technique. It is shown that both moving target location in the SAR look and its shift direction can be extracted.
Synthetic aperture radar is a very popular and widely used instrument for various remote sensing tasks. In the paper, we propose several novel ideas for improvement of the efficiency of the modern SAR systems. At first, the problem of the automatic image stitching is considered. Instead of the common cross-correlation based solution the local features detection and description techniques are proposed. Secondly, we analyze the problem of the moving target parameters estimation.
Synthetic aperture radar (SAR) systems are very popular instrument for high-resolution image of ground surface. Unlike to optical systems, SAR can be used in all weather and lighting conditions. A basic idea of SAR technique is coherent processing of received signals on a moving platform (aircraft or satellite). The main challenge is to perform very precise measurements of platform position at each moment of time.
Intelligent transportation systems are rapidly growing mainly due to active development of novel hardware and software solutions. In the paper a problem of automatical number plate detection is considered. An efficient two-step approach based on plate candidates extraction with further classification by neural network is proposed. Stroke width transform and contours detection techniques are utilized for the image preprocessing and extraction of regions of interest.
The number plate detection is a key step affecting the overall performance of the number plate recognition system. In the paper a novel algorithm for this purpose is proposed. The approach is based on the detection of text areas using the stroke width transform. More plate candidates are detected using the specifically developed image preprocessing scheme based on set of morphological operators and contour analysis.
Formation of high-resolution SAR images from light-weight platforms is a challenging task primarily due to high instability of such platforms. Additional difficulties are related with the precision of navigation systems. In the paper the problem of residual trajectory deviations are analyzed. An efficient trajectory reconstruction method is proposed. Important practical aspects of the developed approach are discussed. Considered ideas are incorporated into the SAR processing chain.