Mateusz Walczak, Eng.

Department of Experimental Mechanics (ZMD)
Division of Non-Destructive Testing (PBN)
Laboratory of Professional Electronics
position: technician programmer
telephone: (+48) 22 826 12 81 ext.: 404
room: 529
e-mail: mwalczak

Recent publications
1.Lewandowski M., Walczak M., Karwat P., Witek B., Karłowicz P., Research and Medical Transcranial Doppler System, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.1515/aoa-2016-0074, Vol.41, No.4, pp.773-781, 2016
Abstract:

A new ultrasound digital transcranial Doppler system (digiTDS) is introduced. The digiTDS enables diagnosis of intracranial vessels which are rather difficult to penetrate for standard systems. The device can display a color map of flow velocities (in time-depth domain) and a spectrogram of a Doppler signal obtained at particular depth. The system offers a multigate processing which allows to display a number of spectrograms simultaneously and to reconstruct a flow velocity profile.
The digital signal processing in digiTDS is partitioned between hardware and software parts. The hardware part (based on FPGA) executes a signal demodulation and reduces data stream. The software part (PC) performs the Doppler processing and display tasks. The hardware-software partitioning allowed to build a flexible Doppler platform at a relatively low cost.
The digiTDS design fulfills all necessary medical standards being a new useful tool in the transcranial field as well as in heart velocimetry research.

Keywords:

Doppler system, digital signal processing, hardware-software partitioning, field programmable gate arrays

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Karwat P.-IPPT PAN
Witek B.-IPPT PAN
Karłowicz P.-other affiliation
2.Lewandowski M., Walczak M., Steifer T., Zastosowanie metody pełnej akwizycji macierzy do wizualizacji wad w technice UT Phased-Array, PRZEGLĄD SPAWALNICTWA, ISSN: 0033-2364, Vol.88, No.10, pp.43-45, 2016
Abstract:

Ultradźwiękowe systemy Phased-Array pozwalają na różne tryby skanowania i wizualizacji wad oraz zapewniają wyższą jakość inspekcji niż tradycyjne systemy jednokanałowe. Kolejnym krokiem w rozwoju tych systemów będzie metoda akwizycji pełnej macierzy oraz zaawansowane algorytmy rekonstrukcji obrazów. W artykule przedstawiono zasady działania tych technik oraz wymagania jakie stawiają one przed systemami akwizycji i przetwarzania sygnałów. Zaprezentowano także badawczy system Uniwersalnej Platformy Ultradźwiękowej, który został opracowany specjalnie do testowania i praktycznego wdrażania tych metod. Platforma posłużyła do badań i porównania dwóch metod rekonstrukcji przy wykorzystaniu akwizycji pełnej macierzy – metody STA (Synthetic Transmit Aperture) i metody PWI (Plane Wave Imaging).

Keywords:

UT Phased-Array, akwizycja pełnej macierzy, syntetyczna apertura

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Steifer T.-IPPT PAN
3.Gawlikowski M., Lewandowski M., Nowicki A., Kustosz R., Walczak M., Karwat P., Karłowicz P., The Application of Ultrasonic Methods to Flow Measurement and Detection of Microembolus in Heart Prostheses, ACTA PHYSICA POLONICA A, ISSN: 0587-4246, DOI: 10.12693/APhysPolA.124.417, Vol.124, No.3, pp.417-420, 2013
Abstract:

For the last 20 years the world cardiosurgery has presented a considerable change of attitude to mechanical circulatory support. In spite of technological progress the main problems in ventricular assist devices are: thrombosis and low accuracy of flow measurements. In this paper the prototype of multi-gate Doppler flowmeter intended for cardiac assist system ReligaHeart EXT has been presented as well as the possibility of ultrasonic micro embolus detection.

Keywords:

artificial heart, microemboli, ultrasound Doppler

Affiliations:
Gawlikowski M.-other affiliation
Lewandowski M.-IPPT PAN
Nowicki A.-IPPT PAN
Kustosz R.-other affiliation
Walczak M.-IPPT PAN
Karwat P.-IPPT PAN
Karłowicz P.-other affiliation
4.Secomski W., Nowicki A., Wójcik J., Lewandowski M., Walczak M., Tymkiewicz R., Annular array transducer and matched amplifier for therapeutic ultrasound, ARCHIVES OF ACOUSTICS, ISSN: 0137-5075, DOI: 10.2478/v10168-010-0049-6, Vol.35, No.4, pp.653-660, 2010
Abstract:

The use of therapeutic ultrasound continues to grow. A focused ultrasonic wave can increase the tissue temperature locally for the non-invasive cancer treatment or other medical applications. The authors have designed a seven-element annular array transducer operating at 2.4 MHz. Each element was excited by sine burst supplied by a linear amplifier and FPGA control circuits. The acoustic field, generated by a transducer was initially numerically simulated in a computer and next compared to water tank hydrophone measurements performed at 20, 40 and 60 mm focal depth. The results showed good agreement of the measurements with theory and the possibility to focus the ultrasound in the preselected area. The total acoustic power radiated by the annular array was equal to 2.4W.

Keywords:

ultrasonic therapy, annular array transducer, ultrasonic field

Affiliations:
Secomski W.-IPPT PAN
Nowicki A.-IPPT PAN
Wójcik J.-IPPT PAN
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Tymkiewicz R.-IPPT PAN

List of chapters in recent monographs
1.
328
Lewandowski M., Walczak M., Karwat P., Nowicki A., Karłowicz P., Polskie protezy serca, opracowanie konstrukcji, badania kwalifikacyjne, przedkliniczne i kliniczne., rozdział: Wykonanie modelu i implementacja oprogramowania do ultradźwiękowego pomiaru przepływu krwi, FRK, Zabrze. Praca zbiorowa pod redakcją: Kustosz R., Gonsior M., Jarosz A., pp.3-21, 2013

Conference papers
1.Lewandowski M., Walczak M., Witek B., Steifer T., A GPU-based Ultrasound Phased-Array Research System for Non-destructive Testing, IUS 2016, IEEE International Ultrasonics Symposium, 2016-09-18/09-21, Tours (FR), DOI: 10.1109/ULTSYM.2016.7728843, pp.1-4, 2016
Abstract:

Ultrasound Phased-Array (PA) systems for nondestructive testing (NDT) use standard beamforming for line-byline image creation. New methods utilizing full-matrix capture (FMC) enable the application of advance processing algorithms, such as the total focusing method and multi-pass adaptive techniques for enhanced flaw visualization. The effective FMC data acquisition and its real-time processing require a very high data throughput and powerful computational resources. Most commercial PA systems support some form of FMC acquisition, but the limited external data bandwidth prevents this mode of operation from being useful. We have developed a fully programmable ultrasound research system capable of performing FMC data acquisition and image reconstruction with a high framerate. The ultrasound platform is supporting up to 192 parallel TX/RX electronics channels integrated with an embedded control PC and a GPU cluster for parallel processing. The implemented software libraries give the end-user control over TX/RX schemes, the acquisition process and signal processing algorithms. This all-in-one system is a fully flexible tool for the research and evaluation of novel Phased-Array FMC imaging methods and complex signal processing algorithms.

Keywords:

GPU, ultrasound, Phased-Array

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Witek B.-IPPT PAN
Steifer T.-IPPT PAN
2.Witek B., Walczak M., Lewandowski M., Characterization of the STHV748 Integrated Pulser for Generating Push Sequences, IUS 2015, IEEE International Ultrasonics Symposium, 2015-10-21/10-24, Taipei (TW), DOI: 10.1109/ULTSYM.2015.0522, pp.1-4, 2015
Abstract:

Ultrasound transmit push sequences put a high stress on a pulser IC due to power dissipation that could result in overheating. The aim of this work was to determine the safe range of parameters of push sequences for a high-voltage, high-speed, 4-channel pulser STHV748 (STMicroelectronics). The impact of using ceramic capacitors and electrolytic capacitors on the HV supply was also examined. The reaction of the pulser was measured with three output loading conditions. A safe range of values of pulser voltage for a given transmit frequency and sequence length were determined by monitoring chip temperature. Additionally, maximum pulse repetition frequency was evaluated in function of the maximum supply voltage. The STHV748 pulser is capable of generating push sequences. The duty-cycle is a key parameter that determines the safe operating conditions of the pulser. Limiting the amplitude of the HV supply enables us to increase push burst duration or decrease the frequency of the transmit signal.

Keywords:

acoustic radiation force, shear wave imaging, push sequences, HV pulser

Affiliations:
Witek B.-IPPT PAN
Walczak M.-IPPT PAN
Lewandowski M.-IPPT PAN
3.Walczak M., Lewandowski M., Żołek N., Optimization of real-time ultrasound PCIe data streaming and OpenCL processing for SAFT imaging, IUS 2013, IEEE International Ultrasonics Symposium, 2013-07-21/07-25, Praga (CZ), DOI: 10.1109/ULTSYM.2013.0527, Vol.1, pp.2064-2067, 2013
Abstract:

Our goal is to develop a complete ultrasound platform based on real-time SAFT (Synthetic Aperture Focusing Technique) GPU processing. We are planning to integrate all the ultrasound modules and processing resources (GPU) in a single rack enclosure with the PCIe switch fabric backplane. The first developed module (RX64) provides acquisition and streaming of 64 ultrasound channels. We implemented and benchmarked data streaming from the RX64 to the GPU memory and the SAFT image reconstruction on the GPU. A high system performance was achieved using hardware assisted direct memory transfers and pipelined processing workflow. The complete system throughput, including 128 channel data transfer at 16kS per line and low-resolution 256×256 pixel image SAFT reconstruction on a single Nvidia K5000 GPU, reached 450 fps. The obtained results proved the feasibility of the ultrasound real-time imaging system with GPU SAFT processing.

Keywords:

ultrasonic imaging, synthetic aperture, GPGPU, FPGA

Affiliations:
Walczak M.-IPPT PAN
Lewandowski M.-IPPT PAN
Żołek N.-IPPT PAN
4.Lewandowski M., Walczak M., Witek B., Kulesza P., Sielewicz K., Modular & Scalable Ultrasound Platform with GPU Processing, IUS 2012, IEEE International Ultrasonics Symposium, 2012-10-07/10-10, Dresden (DE), DOI: 10.1109/ULTSYM.2012.0518, pp.2071-2074, 2012
Abstract:

The objective of our project is to develop a complete ultrasound platform with real-time GPU processing. The platform is designed to be modular and scalable both in number of ultrasound channels (64-256), as well as in communication bandwidth and processing power. By standardizing on the PCIe switch fabric, we are planning to integrate all the ultrasound modules and processing resources (GPU) in a single rack enclosure. Using PCIe direct peer-to-peer communication for transferring the data from the ultrasound acquisition modules to the GPUs, we maximize the system bandwidth and minimize CPU usage. The first developed module of our platform is RX64 - a 64-channel ultrasound acquisition PCIe card. The RX64 contains a high-end FPGA Altera Stratix IV 70 GX interfaced to: two 32-channels mixed-signal front-end ultrasound modules and two 64-bit 8GB DDR3 SO-DIMM memories for data buffering. We also develop GPU kernels for SAFT based ultrasound imaging, as well as GPU Framework for building complete signal processing pipeline.

Keywords:

ultrasonic imaging, synthetic aperture, GPU, FPGA

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Witek B.-IPPT PAN
Kulesza P.-IPPT PAN
Sielewicz K.-IPPT PAN
5.Lewandowski M., Sielewicz K., Walczak M., A Low-cost 32-channel Module with High-speed Digital Interfaces for Portable Ultrasound Systems, IUS 2012, IEEE International Ultrasonics Symposium, 2012-10-07/10-10, Dresden (DE), DOI: 10.1109/ULTSYM.2012.0159, pp.639-642, 2012
Abstract:

There is a continuous trend towards small and portable ultrasound systems with multichannel processing. The objective of the work was to develop a modular acquisition and processing platform based on the following architecture principles: limited hardware processing, external high-speed data communication and software based on SAFT processing using embedded graphics processing unit (GPU). The acquisition module connected via PCIe or USB 3.0 interface can stream either raw RF data or demodulated ones. A low-power embedded PC with embedded GPU will implement ultrasound signal processing, as well as control and visualization functions. The performed feasibility study showed that AMD APU G-Series embedded x86 CPU+GPU is capable of real-time SAFT image reconstruction at limited resolution.

Keywords:

ultrasonic imaging, synthetic aperture, medical electronics, GPU, FPGA

Affiliations:
Lewandowski M.-IPPT PAN
Sielewicz K.-IPPT PAN
Walczak M.-IPPT PAN
6.Walczak M., Kulesza P., Lewandowski M., Karwat P., Witek B., Implementacja w układzie FPGA wybranego filtru ech stałych dla wielobramkowego systemu Dopplera przezczaszkowego, 57 Otwarte Seminarium z Akustyki, 2010-09-20/09-24, Gliwice (PL), pp.209-212, 2010
Abstract:

W artykule opisano wybór i implementację filtrów ech stałych w programowalnych układach logicznych (FPGA) dla ultradźwiękowego wielobramkowego systemu przezczaszkowego przepływomierza krwi opracowywanego w Zakładzie Ultradźwięków IPPT PAN. Implementacja filtrów w FPGA miała na celu redukcję obciążenia softwarowego przetwarzania sygnałów dopplerowskich. W pracy przedstawiono badania modelowe i porównanie filtrów ech stałych o skończonej odpowiedzi impulsowej (SOI) oraz nieskończonej odpowiedzi impulsowej (NOI). Przeanalizowany został zakres stabilnej pracy filtru NOI. Wyselekcjonowany filtr górnoprzepustowy typu SOI został następnie zaimplementowany i zoptymalizowany do architektury układów FPGA oraz zastosowania w przepływomierzu. Zastosowano ekonomiczny układ FPGA Altera Cyclone III EP3C25F324C8. Opracowany filtr ech stałych realizuje 100 identycznych górnoprzepustowych filtrów typu SOI, co zapewnia filtrowanie sygnału dopplerowskiego w 100 bramkach jednocześnie. Filtry operują na 16 bitowych próbkach sygnału, a ich charakterystyka jest programowalna przez 65 16-bitowych współczynników. Zweryfikowano poprawność przetwarzania na komputerze PC w środowisku Altera Quartus II 9.1 oraz ModelSim 6.5b poprzez symulacje i porównanie odpowiedzi impulsowej oraz skokowej filtrów. W wyniku opisanych prac powstała struktura logiczna filtru ech stałych przeznaczona do implementacji w układzie FPGA Cyclone III, zajmująca 5% zasobów logicznych układu oraz 34% zasobów pamięciowych.

Keywords:

ultradźwiękowy Doppler przezczaszkowy, filtry ech stałych, cyfrowe przetwarzanie, FPGA

Affiliations:
Walczak M.-IPPT PAN
Kulesza P.-IPPT PAN
Lewandowski M.-IPPT PAN
Karwat P.-IPPT PAN
Witek B.-IPPT PAN
7.Lewandowski M., Walczak M., Nowicki A., Compact modular Doppler system with digital RF processing, IUS 2009, IEEE International Ultrasonics Symposium, 2009-09-20/09-23, Rzym (IT), DOI: 10.1109/ULTSYM.2009.5441933, pp.1848-1851, 2009
Abstract:

Doppler instruments are widely used for evaluation of the hemodynamic of vascular circulation. The objective of the work was to develop a modular acquisition and processing system to enable the construction of various ultrasound instruments. The developed system consists of two electronic boards with dimensions of 130x82mm in sandwich configuration. Digital signal processing was based on an efficient DSP (Blackfin BF537, Analog Devices, USA) with 128MB RAM and an FPGA (Cyclone III EP3C25, Altera, USA). The system can work as a standalone device with the limited user interface or as a PC peripheral under the control of the application software. The dual channel transcranial PW Doppler flowmeter with multigate processing has been the first application of the developed platform. The acquisition module provides the A/D sampling at 64 MSPS rate with 14-bits resolution and supports ultrasonic transducers within the range of 1–16 MHz. The PC software performs signal processing and visualization of color Doppler, spectrum, flow profile and audio. The developed system is a modern technical solution which enables to build portable Doppler instruments of different classes. The developed prototype of transcranial Doppler will be introduced into production soon.

Keywords:

ultrasound Doppler systems, transcranial aplications, digital RF processing, DSP, FPGA

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Nowicki A.-IPPT PAN

Conference abstracts
1.Walczak M., Lewandowski M., Żołek N., A real-time streaming DAQ for Ultrasonix Research scanner, IUS 14, IEEE International Ultrasonics Symposium, 2014-09-03/09-06, Chicago (US), DOI: 10.1109/ULTSYM.2014.0310, pp.1257-1260, 2014
Abstract:

A new 128 channel parallel acquisition module for the Ultrasonix SonixTouch ultrasound scanner was developed. Although the module provides similar functionality to the original SonixDAQ system, it presents new possibilities of real-time data streaming and processing on GPU, thanks to a fast PCIe communication interface. Direct access and processing of pre-beamformed channel data with fully programmable transmit schemes enables the research implementation of new advanced imaging modalities (eg. plane wave imaging, vector Doppler, shear wave elastography). The presented RX-DAQ system is enriched with a GPU software framework, for Python and Matlab, enabling the integration of user processing functions.

Keywords:

ultrasonic imaging, pre-beamformed data, real-time processing, GPU, FPGA

Affiliations:
Walczak M.-IPPT PAN
Lewandowski M.-IPPT PAN
Żołek N.-IPPT PAN
2.Lewandowski M., Walczak M., Karwat P., Witek B., Nowicki A., Karłowicz P., Research & Medical Doppler platform, 11th Congrès Français d'Acoustique, 2012 IOA annual meeting, 2012-04-23/04-27, Nantes (FR), pp.x1-x6, 2012
Abstract:

A new ultrasound digital transcranial Doppler system (digiTDS) is introduced. The digiTDS enables diagnosis of intracranial vessels which are difficult to penetrate for standard systems. The device can display a color map of flow velocities in time-depth domain and a spectrogram of a Doppler signal received from a particular depth. The system offers a multigate processing that allows to display simultaneously a number of spectrograms and to reconstruct a flow velocity profile. The digital signal processing in digiTDS is partitioned between hardware and software parts. The hardware part (based on FPGA) executes a signal demodulation and reduces data stream. The software part (PC) performs the Doppler processing and display tasks. The hardware-software partitioning allowed to build a flexible Doppler platform at a relatively low cost. The digiTDS design fulfills all necessary medical standards being a new useful tool in transcranial field as well as in heart velocimetry research.

Keywords:

ultrasound transcranial Doppler, RF signal processing, DSP, FPGA

Affiliations:
Lewandowski M.-IPPT PAN
Walczak M.-IPPT PAN
Karwat P.-IPPT PAN
Witek B.-IPPT PAN
Nowicki A.-IPPT PAN
Karłowicz P.-other affiliation