Anton Myagotin

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Reconstruction Algorithms for Parallel-Beam Computed Laminography

Synchrotron radiation computed laminography (CL) was developed to complement conventional compute... more Synchrotron radiation computed laminography (CL) was developed to complement conventional computed tomography as a non-destructive three-dimensional imaging method for the inspection of flat laterally extended objects. Recent progress in hardware at synchrotron sources allows one to record internal evolution of specimens at the micrometer scale and sub-second range but also requires increased reconstruction speed to follow structural changes on-line. This book describes computationally efficient reconstruction methods adapted to the CL acquisition geometry. From the Fourier slice theorem we derive a framework for analytic image reconstruction and outline implementation details of the reconstruction routines in spatial and Fourier domains. Different approaches reducing the reconstruction time by means of parallel and distributed computations are considered and evaluated.

Image Processing for Radiographic Sequences of Foaming Processes: on Example of Metal Foams

Since the invention of metal foams they became an attractive material for different industrial an... more Since the invention of metal foams they became an attractive material for different industrial and engineering applications. The physical backgrounds of metal foaming, relations between the microstructure of metal foams and their macroscopical properties, and controllable foaming, however, are still disputed topics. In this work we develop image processing methods for the quantitative investigation of coalescence processes, for the characterization of material flows during foaming, and for the recognition of basic structural elements such as lamella and pores. First the methods are evaluated on synthetic projection image sequences. Further, they are applied to the radiographic sequences of real metal foaming. The backgrounds of the methods are a new coalescence measure and developed technique for the detection of coalescence events, a novel combination of image processing steps for the recognition of round bubbles, and an established tensor approach for the estimation of velocity ve...

Microsystem and Microelectronic Devices Investigated by Synchrotron-Radiation Imaging Techniques

Due to increasing packing density and ongoing miniaturization there is a growing need for non-des... more Due to increasing packing density and ongoing miniaturization there is a growing need for non-destructive quality assurance of devices in microsystem technology, especially for techniques providing high spatial resolution. The tendency towards short electrical interconnections often results in burried structures which cannot be verified visually. In laboratories, various x-ray techniques are routinely applied to provide non-destructive insight into materials and devices. Successful application to microsystem devices is sometimes restricted, however, for instance due to limited spatial resolution and/or intensity of laboratory x-ray imaging setups. X-ray imaging using synchrotron radiation allows us to overcome a number of limitations. This paper introduces principles of both laboratory and synchrotron methods and shows their applications to imaging of microelectronic devices. Typical tasks of quality inspection usually accompanying the microsystem development cycle are demonstrated ...

format_quoteSRCL effectively detects µm-sized voids in flip-chip solder bumps, showcasing its precision in identifying structural defects.format_quote

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Calculation of the velocity vector field of metal foaming in radiographic sequences

Optoelectronics, Instrumentation and Data Processing

X-ray radiography is extended by a digital image processing method for measuring the velocity vec... more X-ray radiography is extended by a digital image processing method for measuring the velocity vector field of metal foaming in radiographic sequences. A tensor approach coupled with interpolation using an adaptive Gaussian window is proposed. The method was successfully tested on experimental images.

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Efficient implementation of the image rotation method using chirp Z-transform

Pattern Recognition and Image Analysis

ABSTRACT The implementation of an image rotation method based on the chirp Z-transform is present... more ABSTRACT The implementation of an image rotation method based on the chirp Z-transform is presented. Low computational costs of the algorithm are achieved by performing the chirp Z-transform using convolution in the Fourier domain. The series of numerical experiments supports the preservation of the image quality, even for multiple rotations.

Real-time image-content-based beamline control for smart 4D X-ray imaging

Journal of Synchrotron Radiation, 2016

Real-time processing of X-ray image data acquired at synchrotron radiation facilities allows for ... more Real-time processing of X-ray image data acquired at synchrotron radiation facilities allows for smart high-speed experiments. This includes workflows covering parameterized and image-based feedback-driven control up to the final storage of raw and processed data. Nevertheless, there is presently no system that supports an efficient construction of such experiment workflows in a scalable way. Thus, here an architecture based on a high-level control system that manages low-level data acquisition, data processing and device changes is described. This system is suitable for routine as well as prototypical experiments, and provides specialized building blocks to conduct four-dimensionalin situ,in vivoandoperandotomography and laminography.

Direct Fourier Inversion Reconstruction Algorithm for Computed Laminography

IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, Jan 24, 2016

Synchrotron radiation computed laminography (CL) was developed to complement conventional compute... more Synchrotron radiation computed laminography (CL) was developed to complement conventional computed tomography as a non-destructive three-dimensional (3D) imaging method for the inspection of flat thin objects. Recent progress in hardware at synchrotron sources allows one to record internal evolution of specimens at the micrometer scale and sub-second range but also requires increased reconstruction speed to follow structural changes on-line. A 3D image of the sample interior is usually reconstructed by the well-established filtered backprojection (FBP) approach. Despite of a great success in the reduction of reconstruction time via parallel computations, the FBP algorithm still remains a time consuming procedure. A promising way to shorten computation time significantly is to perform backprojection directly in frequency domain (a direct Fourier inversion (DFI) approach). The corresponding algorithms are rarely considered in the literature because of a poor performance or inferior re...

Method for Non-Destructive Flaw Diagnosis in Composite Components Provided with a Metallic or Ceramic Foam Core

Navigation of Autonomous Underwater Vehicles Using Acoustic and Visual Data Processing

In Situ Radiography of the Metal Foaming Processes: A Quantitative Analysis

Methods for evaluation of series of projection images by quantitative image analysis have been de... more Methods for evaluation of series of projection images by quantitative image analysis have been developed and applied to the investigation of metal foaming processes by in-situ real-time radiography. In-situ radiography allows one to image the temporal structure evolution during the foam-ing process and has been applied [1–5] to yield detailed information about metal foaming by the powder-metallurgical production method. Internal structural changes such as bubble ex-pansion, structural coarsening, bubble coalescence, collapse and drainage could be observed non-destructively and investigated qualitatively. In-depth statistical evaluation of two-dimensional (2d) projection image sequences was hardly ever performed up to now for the study of metal foams. In this paper we report dif-ferent methods for the quantitative analysis of 2d projection image sequences which allow us to compare characteristic statistical properties of the temporal structure evolution during foam-ing. In particular...

format_quoteCombined in-situ x-ray radiography and image processing established a quantitative measure for coalescence, pivotal for foam stability investigations.format_quote

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Global extremum searching algorithm for the AUV guidance toward an acoustic buoy

OCEANS 2011 IEEE - Spain, 2011

ABSTRACT This work presents an algorithm for the autonomous underwater vehicle (AUV) guidance tow... more ABSTRACT This work presents an algorithm for the autonomous underwater vehicle (AUV) guidance toward an acoustic signal source. A series of time-of-flight measurements for acoustic sound waves emitted by the source is used in order to determine a desired motion direction. Automatic guidance is provided utilizing an extremum search controller. Proposed algorithms were modeled and tested using numerical experiments.

Measuring system for the registration of pseudo-noise hydroacoustic signals

2008 9th International Conference on Actual Problems of Electronic Instrument Engineering, 2008

In this work we describe a developed FPGA-based measuring system that allows one to register navi... more In this work we describe a developed FPGA-based measuring system that allows one to register navigational and control pseudo-noise hydro-acoustic signals accurately and in real time. We present experiment results produced with a prototype of the measuring system in a real environment under shallow sea conditions.

Efficient volume reconstruction for parallel-beam computed laminography by filtered backprojection on multi-core clusters

IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, Jan 17, 2013

Computed laminography (CL) was developed to use X rays from synchrotron sources for high-resoluti... more Computed laminography (CL) was developed to use X rays from synchrotron sources for high-resolution imaging of the internal structure of a flat specimen from a series of twodimensional (2D) projection images. The projections are acquired by irradiation of the sample under different rotation angles where the object rotation axis is inclined with respect to the beam direction. This yields for laterally extended objects a more uniform average transmitted intensity during sample rotation compared to computed tomography (CT). The reconstruction problem of CL cannot be reduced to a data-efficient 2D case (as for parallel-beam CT) since each single slice perpendicular to the rotation axis requires a 2D region on the detector as input data for all projection directions. This paper describes a computationally efficient reconstruction procedure based on filtered backprojection (FBP) adapted to the CL acquisition geometry. From the Fourier slice theorem we derive a framework for analytic image...

AUV positioning model employing acoustic and visual data processing

This paper describes a positioning model of an autonomous underwater vehicle attaining an underwa... more This paper describes a positioning model of an autonomous underwater vehicle attaining an underwater target equipped with an acoustic buoy. The model combines acoustic and vision-based navigation principles. The acoustic guidance assumes a one-way asynchronous signal exchanging mode. A visionbased positioning employs log-polar transformations of camera images. A PID controller is used to change the vehicle position and course. The corresponding control and error functions are given. The model was implemented in a programm code and thereafter a number of numerical tests were carried out. The tests confirmed an reliability of the developed algorithms.

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Quantitative coalescence measurements for foaming metals by in situ radiography

Scripta Materialia, 2012

ABSTRACT In situ X-ray radiography and spatio-temporal image analysis yield quantitative informat... more ABSTRACT In situ X-ray radiography and spatio-temporal image analysis yield quantitative information about coalescence during metal foam formation and decay. The choice of weighting every detected coalescence event by its projected area yields reliable information about the impact of coalescence on structural coarsening. The comparison of two particle-stabilized metal foams containing ceramic particles of different sizes demonstrates that the stabilization effect is provided by solid particles which are small in comparison to the average film thickness of the foamed liquid melt.

On the implementation of computed laminography using synchrotron radiation

Review of Scientific Instruments, 2011

Hard x rays from a synchrotron source are used in this implementation of computed laminography fo... more Hard x rays from a synchrotron source are used in this implementation of computed laminography for three-dimensional (3D) imaging of flat, laterally extended objects. Due to outstanding properties of synchrotron light, high spatial resolution down to the micrometer scale can be attained, even for specimens having lateral dimensions of several decimeters. Operating either with a monochromatic or with a white synchrotron beam, the method can be optimized to attain high sensitivity or considerable inspection throughput in synchrotron user and small-batch industrial experiments. The article describes the details of experimental setups, alignment procedures, and the underlying reconstruction principles. Imaging of interconnections in flip-chip and wire-bonded devices illustrates the peculiarities of the method compared to its alternatives and demonstrates the wide application potential for the 3D inspection and quality assessment in microsystem technology.

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Phase contrast laminography based on Talbot interferometry

Optics Express, 2012

Synchrotron laminography is combined with Talbot grating interferometry to address weakly absorbi... more Synchrotron laminography is combined with Talbot grating interferometry to address weakly absorbing specimens. Integrating both methods into one setup provides a powerful x-ray diagnostical technique for multiple contrast screening of macroscopically large flat specimen and a subsequent non-destructive three-dimensional (3-D) inspection of regions of interest. The technique simultaneously yields the reconstruction of the 3-D absorption, phase, and the so-called dark-field contrast maps. We report on the theoretical and instrumental implementation of of this novel technique. Its broad application potential is exemplarily demonstrated for the field of cultural heritage, namely study of the historical Dead Sea parchment.

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Investigation of hybrid pixel detector arrays by synchrotron-radiation imaging

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2006

... By this, we are able to assess the structural perfection of components and solder joints. ...... more

Coalescence measurements for evolving foams monitored by real-time projection imaging

Measurement Science and Technology, 2009

ABSTRACT Real-time radiographic projection imaging together with novel spatio-temporal image anal... more ABSTRACT Real-time radiographic projection imaging together with novel spatio-temporal image analysis is presented to be a powerful technique for the quantitative analysis of coalescence processes accompanying the generation and temporal evolution of foams and emulsions. Coalescence events can be identified as discontinuities in a spatio-temporal image representing a sequence of projection images. Detection, identification of intensity and localization of the discontinuities exploit a violation criterion of the Fourier shift theorem and are based on recursive spatio-temporal image partitioning. The proposed method is suited for automated measurements of discontinuity rates (i.e., discontinuity intensity per unit time), so that large series of radiographs can be analyzed without user intervention. The application potential is demonstrated by the quantification of coalescence during the formation and decay of metal foams monitored by real-time x-ray radiography.

Coalescence analysis for evolving foams via optical flow computation on projection image sequences

Journal of Synchrotron Radiation, 2012

Synchrotron radiation research is rapidly expanding with many new sources of radiation being crea... more Synchrotron radiation research is rapidly expanding with many new sources of radiation being created globally. Synchrotron radiation plays a leading role in pure science and in emerging technologies. The Journal of Synchrotron Radiation provides comprehensive coverage of the entire field of synchrotron radiation research including instrumentation, theory, computing and scientific applications in areas such as biology, nanoscience and materials science. Rapid publication ensures an up-to-date information resource for scientists and engineers in the field. Crystallography Journals Online is available from journals.iucr.org J. Synchrotron Rad. (2012). 19, 483-491 Anton Myagotin et al. • Optical flow coalescence analysis for evolving foams research papers

format_quoteSynchrotron radiography's high flux density enables rapid imaging of foam evolution, essential for observing transient coalescence events.format_quote

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