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Augmented reality is popular and rapidly growing direction. It is successfully used in medicine, education, engineering and entertainment. In the paper, basic principles of typical augmented reality system are described. An efficient hybrid visual tracking algorithm is proposed. The approach is based on combining of the optical flow technique with direct tracking methods. It is demonstrated that developed...
Nowadays automatic methods based on artificial intelligence are rapidly growing. In the paper, a problem of automatic target recognition in synthetic aperture radar images is described. It is demonstrated, that two different machine learning instruments can provide very high classification accuracy. In particular, support vector machines with proper optimization and developed local feature set gives...
SAR is a very popular instrument for imaging of the ground surface. Possibility of high-resolution image formation makes it superior tool for various information extraction tasks. In the paper, a problem of automatic target recognition is comprehensively analyzed. An idea of azimuth and range target profiles fusion is proposed. It is demonstrated, that usage of a proper image preprocessing with appropriate...
Synthetic aperture radar (SAR) is a powerful tool for remote sensing of the Earth surface. In the paper, several applications of pattern detection and recognition algorithms for extraction of information from SAR images are discussed. In particular, an idea of usage of optical flow techniques for automatic estimation of the moving target displacements from a sequence of single-look SAR images is proposed...
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...
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. In addition, the linear road segments...
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...
Synthetic aperture radar is a popular instrument for high-resolution imaging. Usage of state-of-the-art image and signal processing solutions allows to significantly increase the efficiency of such systems. In the paper two important applications of computer vision algorithms are described. In particular, usage of local feature extraction algorithms for the radar image stitching. This results in the...
Autofocusing is one of the key steps in the high-resolution SAR imaging. In the paper several important improvements to the recently developed local-quadratic map-drift autofocus are proposed. Important SAR image preprocessing steps applied before the local Doppler rate errors estimation are described. The weighting scheme for the evaluation of residual cross-track acceleration components is developed...
Autofocusing is one of the key steps in the high-resolution SAR imaging. In the paper several important improvements to the recently developed local-quadratic map-drift autofocus are proposed. Important SAR image preprocessing steps applied before the local Doppler rate errors estimation are described. The weighting scheme for the evaluation of residual cross-track acceleration components is developed...
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...
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...
The accuracy of trajectory measurements is one of the crucial factors in high-resolution SAR imaging. Common navigation systems often do not fulfill the requirements that results in significant image quality degradation. In the paper, a new autofocus algorithm for the reconstruction of the SAR platform trajectory deviations is proposed. The approach is based on the estimation of the Doppler rate errors...
Presence of phase errors in radar data is a crucial problem for high-resolution SAR imaging. In the paper, a new idea for representation of an arbitrary phase error by its local approximations is proposed. Within such approach, a general analytical expression for the resolution degradation of multi-look SAR images is derived. The principle of local approximations is also used in a novel autofocusing...
The quality of high-resolution SAR imaging is strictly related with the precision of the platform trajectory measurements. This is one of the crucial points in the case of image formation from light-weight aircrafts and UAV platforms, which undergone significant trajectory instabilities in real flight conditions. In the paper, a new approach for the residual range-dependent phase error restoration...
Insufficient accuracy of trajectory measurements is a pressing problem for modern high-resolution airborne SAR systems. In the paper, a novel method for the estimation of residual trajectory deviations from SAR data is proposed. The method is based on the map-drift autofocus principle used to estimate the cross-track components of the aircraft acceleration on short time intervals. The estimated acceleration...
Uncompensated phase errors lead to quality degradation of SAR images what is especially critical for high-resolution systems. In the paper, a novel approach to the stripmap autofocus is proposed. The idea of the method is to estimate the local quadratic phase errors by processing small data blocks. The conventional map-drift autofocus (MDA) algorithm is used for such estimation. Then, by a double...
Instabilities of the antenna beam orientation lead to radiometric errors in SAR images. This is one of the most difficult problems for the application of the range-Doppler algorithm, which implies a straight-line flight with a constant orientation. In the paper, we propose a radiometric correction approach for compensation of such instabilities.
The application of the clutter-lock technique in case of fast and significant instabilities of the antenna orientation leads to strong geometric distortions in SAR images. In the paper we propose a radiometric correction approach which could be used with SAR processing algorithms without clutter-lock. The technique has been tested by using a Ku-band airborne SAR system, installed on a light-weight...
Small airborne SAR systems suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions in SAR images. In the paper, we describe a time-domain multi-look stripmap SAR processing algorithm with built-in geometric correction. In the algorithm, the azimuth reference functions and range migration curves are designed...
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