R&D is also a strong side of our team. Below list contains research papers published in the international journals and theses from a number of international conferences. If you found any interesting information, please do not hesitate to contact us.

1.

Advanced Image Tracking Approach for Augmented Reality Applications

Ievgen M. Gorovyi, Dmytro S. Sharapov

Proceedings of Signal Processing Symposium (SPSympo-2017), 12-14 September, Jachranka, Poland, pp.266-270 (2017)

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 technique allows to achieve stable and precise results. Comparative experimental results are included.

2.

Framework for Real-Time User Positioning in GPS Denied Environments

Ievgen Gorovyi, Alexey Roenko, Alexander Pitertsev,Ievgen Chervonyak, Vitalii Vovk

Proceedings of Signal Processing Symposium (SPSympo-2017), 12-14 September, Jachranka, Poland, pp.302-306 (2017)

In the paper, a system for real-time positioning is proposed. Developed signal processing algorithms for precise user localization and navigation are described. It is demonstrated that proper calibration and received signal filtering leads to improvement of positioning accuracy. Peculiarities of Bluetooth Low Energy beacons as signal sources are considered. Key components of the created software development kit are described. Experimental results of testing on mobile platforms are given.

3.

Comparative Analysis of Convolutional Neural Networks and Support Vector Machines for Automatic Target Recognition

Ievgen M. Gorovyi, Dmytro S. Sharapov

Proceedings of the 2017 Microwaves, Radar and Remote Sensing Symposium (August 29-31, Kiev, Ukraine), pp.63-66 (2017)

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 competitive results. Secondly, a novel architecture of convolutional neural network is proposed. Important practical aspects of both methods are analyzed. Experimental results for MSTAR are given.

4.

Efficient Object Classification and Recognition in SAR Imagery

Ievgen M. Gorovyi, Dmytro S. Sharapov

Proceedings of the 18th International Radar Symposium (IRS 2017), Prague, Czech Republic, June 28-30, 2017.

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 feature extraction steps allow to achieve a competitive recognition accuracy while keeping a low-dimensionality of feature vectors. Experimental results are discussed for a publicly available MSTAR dataset.

5.

Real-Time System for Indoor User Localization and Navigation using Bluetooth Beacons

Ievgen Gorovyi, Alexey Roenko, Alexander Pitertsev,Ievgen Chervonyak, Vitalii Vovk

IEEE First Ukraine Conference on Electrical and Computer Engineering (UKRCON) , Kiev, Ukraine, May 29-June 2, pp. 1025-1029, 2017.

Real-time user positioning and navigation services are widely used daily by millions of people. The challenge is that common global positioning systems fail in indoor environment or in scenes with a limited sky view. In the paper, the indoor navigation framework based on the Bluetooth beacons is proposed. Such system allows user to obtain the position in GPS denied environment on a real-time basis. Key steps for precise localizing and main components of the developed framework are considered. Initial experimental results are provided

6.

Pattern Detection and Recognition in SAR Images

Ievgen M. Gorovyi, Dmytro S. Sharapov

IEEE First Ukraine Conference on Electrical and Computer Engineering (UKRCON) , Kiev, Ukraine, May 29-June 2, pp. 123-127, 2017.

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. It is shown, how this technique can be adopted for SAR imagery. In addition, it is demonstrated that local feature descriptors can be used for automatic SAR panorama creation without information about reference platform orientation. Finally, a problem of automatic target recognition is analyzed. It is shown, that a fusion of azimuth and range profiles of the ground target allows to achieve a competitive accuracy using quite compact feature vectors.

7.

Focusing of Static and Moving Targets in Real Flight Conditions using SAR Technique

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

IEEE Radar Methods and Systems Workshop (RMSW), Kiev, Ukraine, September 27-28, 2016.

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.

8.

A Novel Algorithm for Estimation of Moving Target Parameters with Single-Antenna SAR

Ievgen M. Gorovyi and Dmytro S. Sharapov

International Conference on Mathematical Methods in Electromagnetic Theory(MMET-2016), Lviv, Ukraine , July 5-7, pp. 188-191 (2016)

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 are automatically detected from the multi-look SAR image using the Canny edge map and local pixels intensity gradient analysis. Proposed ideas are incorporated into the novel algorithm capable to unambiguously extract the moving target parameters using the single-antenna SAR system. Experimental examples obtained with X-band airborne SAR system are illustrated as well.

9.

Frame-Based SAR Processing and Automatic Moving Targets Parameters Extraction

I.M. Gorovyi, D.S. Sharapov and D.M. Vavriv

Proceedings of the 17th International Radar Symposium (IRS 2016), Krakow, Poland, May 10-12, 2016, pp.1-4 (2016)

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. It is shown that the optical flow techniques can be used for the automatic extraction of the moving target shifts from the sequence of SAR looks. Experimental examples with real SAR data are illustrated and comprehensively discussed.

10.

Efficient Two-Step Approach for Automatic Number Plate Detection

I.M. Gorovyi

International Journal of Electronics and Telecommunications, Vol. 61, #4, pp.351-356 (2015)

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. Different local feature sets are used for the final number plate detection step. Efficiency of the developed method is tested with real datasets.

11.

Robust number plate detector based on stroke width transform and neural network

I.M. Gorovyi and I.O. Smirnow

Proceedings of Signal Processing Symposium (SPSympo-2015), 10-12 June, Debe, Poland, pp.163-166 (2015)

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. The final number plate candidates are properly classified using the neural network which is learned from the training dataset. Experiment results indicate on the high performance of the developed methodology

12.

Efficient data focusing and trajectory reconstruction in airborne SAR systems

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of Signal Processing Symposium (SPSympo-2015), 10-12 June, Debe, Poland, pp.179-183 (2015)

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. The algorithm efficiency is proven via examples of real SAR data obtained with an X-band airborne SAR system.

13.

Multi-Look SAR Processing with Road Location and Moving Target Parameters Estimation

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of the 16th International Radar Symposium (IRS 2015), June 23-26, Dresden, Germany, Vol. 1, pp.581-586 (2015)

Multi-look processing is a well-known technique actively used in the SAR research community. In the paper, a method is described for the extraction of the ground moving targets parameters from a sequence of SAR look images obtained with a single-antenna SAR. The method calls for the automatic road extraction from the multi-look SAR images. The proposed road detection and location algorithm is based on the Canny edge detector and the histograms of image gradient directions. The estimated road coordinates are used for unambiguous evaluation of the moving targets parameters, namely the velocity components and the coordinates

14.

High-Performance Autofocusing for Light-Weight SAR Platforms

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of the 12th European Radar Conference (EURAD-2015), 9-11 September 2015, Paris, France, pp.556-559 (2015)

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. It is illustrated that accounting of the local image contrast leads to better estimation precision. Also it is shown that the usage of measured real antenna orientation angles results in more reliable estimation of the local Doppler rate errors. Performance of the trajectory reconstruction technique is tested with experimental data obtained with X-band airborne SAR system.

15.

Estimation of Uncompensated Trajectory Deviations and Image Refocusing for High-Resolution SAR

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of the German Microwave Conference (GeMiC-2015), 16-18 March, Nurnberg, Germany, pp.186-189 (2015)

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 on a sequence of short-time intervals. The method is capable of estimation of time-varying and range-dependent phase error functions. The key steps of the developed technique are illustrated. The method is demonstrated on experimental data obtained with an X-band airborne SAR system.

16.

Application of Computer Vision Techniques in Modern SAR Systems

I.M. Gorovyi and D.S. Sharapov

International Young Scientists Forum on Applied Physics (YSF-2015), Dnipropetrovsk, Ukraine, pp.1-4 (2015)

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 automatical panorama creation without usage of the navigation data. In addition, the road location approach based on the stroke width transform and contour analysis is proposed. Application of the developed methods is illustrated with real SAR data examples

17.

Modifications of Range-Doppler Algorithm for Compensation of SAR Platform Motion Instabilities

I.M. Gorovyi, O.O. Bezvesilniy

International Journal of Electronics and Telecommunications, Vol. 60, #3, pp.225-231 (2014)

Two modifications of the range-Doppler algorithm (RDA) have been proposed to solve problems of SAR platform motion instabilities. First, the multi-look processing based on the RDA with an extended Doppler bandwidth has been introduced for correction of radiometric errors. Second, the RDA has been modified to perform SAR image formation on short-time acquisition intervals to use it in a recently-developed local-quadratic map-drift autofocus (LQMDA) method. The performance of the methods is illustrated with experimental data obtained by airborne SAR systems

18.

A Novel Trajectory Restoration Algorithm for High-Resolution SAR Imaging

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of the 15th International Radar Symposium (IRS 2014) (June 16-18, Gdansk, Poland), pp.170-173 (2014)

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 is proposed. According to the method, the cross-track aircraft accelerations are evaluated via a specifically developed weighted estimation procedure. The reconstructed residual trajectory deviations are used for the range-dependent motion errors compensation. The corresponding experimental results are also demonstrated.

19.

X-Band SAR System for Light-Weight Aircrafts

D.M. Vavriv, O.O. Bezvesilniy, R.V. Kozhin, V.V. Vinogradov,V.A. Volkov, I.M. Gorovyi and S.S. Sekretarov

Proceedings of the 15th International Radar Symposium (IRS 2014) (June 16-18, Gdansk, Poland), pp.501-505 (2014)

In the paper, an X-band airborne SAR system developed and produced at the Institute of Radio Astronomy is described. The system is designed to be operated from light-weight aircrafts. Implemented hardware and real-time software solutions are discussed. Several original approaches to the post-processing of the recorded data are considered. Experimental results are also presented and discussed.

20.

Residual Phase Errors and Autofocusing in Airborne SAR Systems

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

Proceedings of the 2014 Microwaves, Radar and Remote Sensing Symposium (September 23-25, 2014, Kiev, Ukraine), pp.103-106 (2014)

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 approach that allows estimating and compensating of an arbitrary residual phase error function via measuring local quadratic phase errors.

21.

A new autofocus method for high-resolution synthetic aperture radar imaging

I.M. Gorovyi, O.O. Bezvesilniy and D.M. Vavriv

14th Kharkiv Young Scientists Conference on radiophysics, electronics, photonics and biophysics (YSC-2014), 14-17 October 2014, pp.1 (2014)

The quality of images obtained with a synthetic aperture radar (SAR) strictly depends on the platform trajectory measurement precision. A crucial point is that even expensive navigation systems often do not fulfill the accuracy requirements. This is especially critical for a high-resolution SAR imaging. In the paper a novel approach which can successfully handle the residual deviations is proposed.

22.

Correction of radiometric distortions in images in the case of SAR processing with range-Doppler algorithm

I.M. Gorovyi, O.O. Bezvesilniy

Radiophysics and Electronics, Vol. 4, #2, pp.45-50 (2013)

Synthetic aperture radar (SAR) is an effective instrument for the formation of high-resolution images of the earth surface. Trajectory instability is one of the factors that affect the quality of the obtained images. The problem is that even in the case of application of a common motion compensation procedure, which is necessary for synthetic aperture formation, instabilities of the antenna beam orientation are still left uncompensated. This leads to radiometric distortions in SAR images. This problem is especially critical in the case of SAR processing with frame-based algorithms based on FFT (for example, the range-Doppler algorithm), which assume the constant antenna beam orientation within the large data blocks. In this paper the method of radiometric correction of SAR images is considered in the case of processing of SAR data in the frequency domain. Its idea is based on the formation of extended number of looks which corresponds to the broadening of the processed Doppler bandwidth. It is shown that such broadening allows to compensate the influence of two effects: changes of the real antenna beam orientation angles in respect to the aircraft velocity vector and also the possible additional broadening of the Doppler bandwidth of the received signals due to the application of the common motion compensation procedure. The obtained extended number of looks is used for the restoration of the multi-look SAR image without radiometric errors. The introduced methods of radiometric correction are an efficient alternative to expensive antenna stabilization systems and actively used in operating SAR systems. The efficiency of the developed algorithms is illustrated by real SAR data examples.

23.

Effects of local phase errors in multi-look SAR images

O.O. Bezvesilniy, I.M. Gorovyi

Progress In Electromagnetics Research B, Vol. 53, pp.1-24 (2013)

The synthetic aperture radar (SAR) is a widely used instrument for high-resolution imaging from aircraft or satellite platforms. In the paper, the problem of the defocusing of multi-look SAR images by uncompensated phase errors presented in the received data is analyzed. It is shown that the phase errors on a multi-look processing interval can be effectively described in terms of local quadratic and local linear phase errors. Approximate analytical expressions are derived to describe the azimuth resolution degradation. Criteria for acceptable phase errors are given. The obtained results are verified by numerical simulations. The approach is illustrated by two typical motion errors: slow deflections of a SAR platform trajectory from a reference flight line and periodic trajectory deviations.

24.

Efficient estimation of residual trajectory deviations from SAR Data

O.O. Bezvesilniy, I.M. Gorovyi and D.M. Vavriv

Proceedings of the 10th European Radar Conference (EURAD-2013), 9-11 October 2013, Nuremberg, Germany, pp.188-191 (2013)

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 is then integrated to retrieve the residual trajectory deviations on the whole data frame. The proposed approach has been successfully tested with an X-band airborne SAR system.

25.

Local-Quadratic Map-Drift Autofocus for Synthetic Aperture Radars

O.O. Bezvesilniy, I.M. Gorovyi

Radiofizika i Radioastronomia, Vol. 17, #2, pp.182-193 (2012)

Uncompensated phase errors lead to quality degradation of images obtained by synthetic aperture radars (SAR). This effect is especially critical for systems with high spatial resolution. A novel approach to estimating residual phase errors in stripmap SAR signals is suggested. The idea of the method is to estimate the local quadratic phase errors on short time intervals with the subsequent reconstruction of the unknown phase error on the time intervals of arbitrary length. The map-drift autofocus (MDA) algorithm is used for the local estimation. The performance of the proposed method is demonstrated with real radar data examples.

26.

Estimation of Phase Errors in SAR Data by Local-Quadratic Map-Drift Autofocus

O.O. Bezvesilniy, I.M. Gorovyi and D.M. Vavriv

Proceedings of the 13th International Radar Symposium (IRS-2012), Warsaw, Poland, May 23-25, 2012, pp.376-381 (2012)

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 integration of the estimated quadratic errors, an arbitrary residual phase error for large data blocks is evaluated. The performance of the proposed method is demonstrated with data obtained with an X-band airborne SAR system.

27.

Autofocus: The Key to a High SAR Resolution

O.O. Bezvesilniy, I.M. Gorovyi and D.M. Vavriv

Proceedings of the 14th International Conference on Mathematical Methods in Electromagnetic Theory (MMET-2012), Kharkiv, Ukraine, August 28-30, 2012, pp.504-507 (2012)

Uncompensated phase errors lead to a significant quality degradation of images obtained with a synthetic aperture radar (SAR). In the paper, an efficient approach to the SAR autofocusing is proposed. The main idea of the method is the usage of independent local phase error estimates on short time intervals for an arbitrary phase error reconstruction. The residual phase error is retrieved via a double integration of the estimated time-series of the second derivative of the phase error. A high efficiency of the approach is confirmed by experimental results.

28.

SAR Processing Algorithm with Built-In Geometric Correction

O.O. Bezvesilniy, I.M. Gorovyi, S.V. Sosnytskiy, V.V. Vinogradov and D.M. Vavriv

Radiofizika i Radioastronomia, Vol. 16, #1, pp.98-108 (2011)

Synthetic aperture radar (SAR) systems onboard small aircrafts suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions in SAR images. In order to correct the distortions, we propose 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 to produce SAR images directly on a correct rectangular grid on the ground plane. The proposed technique has been successfully tested by using a Ku-band airborne SAR system installed onboard light-weight aircraft.

29.

Multi-look radiometric correction of SAR images

O.O. Bezvesilniy, I.M. Gorovyi, V.V. Vinogradov and D.M. Vavriv

Radiofizika i radioastronomiya, Vol. 16, #4, pp.424-432 (2011)

Deviations of the aircraft trajectory and instabilities of the aircraft orientation lead to non-uniform illumination of the ground by the antenna beam and, as a result, to radiometric errors in radar images obtained with airborne synthetic aperture radars (SAR). The clutter-lock technique is commonly used to avoid the radiometric errors. However, this approach leads to strong geometric distortions in SAR images in the case of fast and significant instabilities of antenna orientation. Here we propose a multi-look radiometric correction technique which can be used instead of the clutter-lock. The proposed approach has been tested by using a Ku-band airborne SAR system installed onboard a light-weight aircraft.

30.

Range-Doppler Algorithm with Extended Number of Looks

O.O. Bezvesilniy, I.M. Gorovyi, V.V. Vinogradov and D.M. Vavriv

Proceedings of the 2011 Microwaves, Radar and Remote Sensing Symposium (August 25-27, 2011, Kiev, Ukraine), pp.203-206 (2011)

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.

31.

Multi-Look Stripmap SAR Processing Algorithm with Built-In Correction of Geometric Distortions

O.O. Bezvesilniy, I.M. Gorovyi, S.V. Sosnytskiy, V.V. Vinogradov andD.M. Vavriv

Proceedings of the European Conference on Synthetic Aperture Radar (EuSAR'2010), 7-10 June 2010, Aachen, Germany, pp.712-715 (2010)

SAR systems installed on small aircrafts 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 correction of geometric distortions. In the algorithm, the azimuth reference functions and range migration curves are specially designed to produce SAR images directly on a correct rectangular grid on the ground plane. The proposed technique has been successfully tested by using a Ku-band airborne SAR system.

32.

Correction of Radiometric Errors by Multi-look Processing with Extended Number of Looks.

O.O. Bezvesilniy, I.M. Gorovyi, V.V. Vinogradov and D.M. Vavriv

Proceedings of the 11th Int. Radar Symposium (IRS-2010). June 16-18, Vilnius, Lithuania, Vol. 1, pp.26-29 (2010)

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.

33.

Multi-Look SAR Processing with Build-in Geometric Correction

O.O. Bezvesilniy, I.M. Gorovyi, S.V. Sosnytskiy, V.V. Vinogradov

Proceedings of the 11th Int. Radar Symposium (IRS-2010). June 16-18, Vilnius, Lithuania, Vol. 1, pp.30-33 (2010)

Synthetic aperture radar (SAR) systems onboard small aircrafts suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions in SAR images. In order to correct the distortions, we propose 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 to produce SAR images directly on a correct rectangular grid on the ground plane. The proposed technique has been successfully tested by using a Ku-band airborne SAR system installed onboard light-weight aircraft.

34.

Improving SAR Images: Built-In Geometric and Multi-Look Radiometric Corrections

O.O. Bezvesilniy, I.M. Gorovyi, S.V. Sosnytskiy, V.V. Vinogradov

Proceedings of the 7th European Radar Conference (EuRAD'2010), 30 September - 1 October 2010, Paris, France, pp.256-259 (2010)

Abstract—SAR systems installed on small aircrafts and UAVs suffer from trajectory deviations and instabilities of antenna orientation. These kinds of motion errors lead to significant geometric distortions and radiometric errors in SAR images. In the paper, we describe a time-domain multi-look stripmap SAR processing algorithm with built-in geometric and multi-look radiometric corrections. Geometric correction is performed due to azimuth reference functions and range migration curves specially designed to produce SAR images directly on a rectangular grid on the ground plane. Radiometric correction is based on multi-look processing with extended number of looks. The proposed techniques have been successfully tested with a Ku-band SAR system installed on a light-weight aircraft.

35.

Multi-look SAR Processing with Built-in Geometric Correction

I.M. Gorovyi, O.O. Bezvesilniy, S.V. Sosnytskiy, V.V. Vinogradov andD.M. Vavriv

6th Int. Young Scientist Conference "Modern Issues in Radio Engineering and Telecommunications" (RT-2010). April 19-24, Sevastopol, Crimea, Ukraine, pp.344 (2010) (in Russian)

In the paper a time-domain multi-look stripmap SAR processing algorithm with built-in geometric correction is considered. In the algorithm, the azimuth reference functions and range migration curves are designed to produce SAR images directly on a correct rectangular grid on the ground plane.

36.

Correction of Radiometric Errors by Multi-look Processing with Extended Number of Looks

I.M. Gorovyi, O.O. Bezvesilniy, V.V. Vinogradov and D.M. Vavriv

6th Int. Young Scientist Conference "Modern Issues in Radio Engineering and Telecommunications" (RT-2010). April 19-24, Sevastopol, Crimea, Ukraine, pp.343 (2010) (in Russian)

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.