The Vantage Research Ultrasound System is a powerful and flexible platform for developing new ultrasonic technologies for biomedical ultrasound, materials science/non-destructive evaluation, and many other applications in research and development.
Read the interview below with Dr. Ron Daigle, Founder and CTO of Verasonics, to learn more about some of the technical aspects of Vantage software architecture and capabilities. Our objective with this interview is to assist current and potential users in gaining a greater breadth of knowledge about this innovative instrument. Dr. Daigle has over 30 years experience in ultrasound research and development and is the author on 32 ultrasound publications and named as an inventor on 10 ultrasound patents.
What would you say are the primary advantages of the Vantage software?
Dr. Daigle: The Vantage software provides the user with full control over all components of an ultrasound system. This allows the user to experiment with custom transmit waveforms, unique scanning sequences and new processing methods. The software allows the user to program to a virtual ultrasound system that completely abstracts the hardware and software components into objects whose attributes are easily specified. And as they become familiar with the MATLAB®-based Verasonics programming interface, users can very quickly implement their ideas for new ultrasound modalities.
Why did Verasonics choose MATLABTM as the interface for controlling the Vantage system?
Dr. Daigle: MATLAB is the high level language used for sequence programming, and user programmed signal and image processing. MATLAB was chosen based on its widespread use in academic institutions and their research labs, and its rich set of built-in functions for data processing, image display and user interface development. In addition, functions coded in other languages such as Java, .NET, Fortran, C and C++ are easily integrated with MATLAB to supplement the processing environment.
Does the use of MATLAB slow down the rate of acquisition and processing of ultrasound data?
Dr. Daigle: The MATLAB language is used only for specifying the sequence programming of the Vantage systems and for user interface controls. Acquisition of ultrasound data is controlled by a hardware sequencer that operates completely independently from the software for deterministic timing of acquisition events. All software processing functions provided by Verasonics are programmed in C or C++ for speed of execution and incorporated into a MEX function (MATLAB External processing function) that is called at the start of sequence execution. In the C environment, processing is highly optimized using multiple threads of execution and SIMD (Single Instruction Multiple Data) vector instructions, enabling real-time software image reconstruction, Doppler processing and image display processing. The MATLAB programming environment is only re-entered for changes in system programming or execution of user provided processing functions (which if desired can also be coded in C or other supported languages.
Can we program the system using C or C++?
Dr. Daigle: For sequence programming, a MATLAB script for defining sequence objects is the only supported model for Vantage users. For user processing functions operating on acquired data, programming can be done in C or C++ and called as external processing functions invoked by sequence events.
Can I use another program such as PYTHON or LabView for controlling the Vantage system?
Dr. Daigle: Any program that is compatible and integrates with MATLAB to allow calling of MATLAB functions can be used to control the Vantage system. MathWorks provides an API (Application Programming Interface) for Python that allows Python to call MATLAB as the computational engine. The MathWorks support site has a number of examples for using MATLAB with LabView.
What Vantage parameters and functions for data acquisition can be controlled by software?
Dr. Daigle: The Vantage software provides the user with full control of all transmit and receive data acquisition parameters, including transmit waveform generation, receive amplifier characteristics, A/D sample rate, and post-digitizer filtering and signal conditioning.
Does the Vantage system allow access to the data before beamforming?
Dr. Daigle: Yes – the digital data from all receive channels are stored in host memory and can be accessed by user provided functions.
If I acquire data using the Vantage system, but want to process it using my own software and signal processing programs, can I do that?
Dr. Daigle: Yes – as mentioned earlier, the user can write their own processing functions in a variety of languages that can be called at defined points in a sequence of events, and access acquired or partially processed data.
What capabilities are included in the Vantage Image Reconstruction software?
Dr. Daigle: The Vantage reconstruction software computes the complex echo signal value at points in the medium imaged by the transducer. The signal value represents the returned echo of the transmit waveform from the media point, as received and focused by the aperture of receiving elements. Multiple acquisitions can be processed and combined for synthetic aperture applications or for frequency or spatial compounding. Geometric regions in the media can be defined to restrict processing to specific spatial locations.
If I acquire ultrasound data from another source, can I process it using the Vantage reconstruction software?
Dr. Daigle: This is possible with proper formatting of the ultrasound data. The format would need to be identical to the format of the acquired data obtained using a sequence program written for the Vantage system. In other words, individual channel data sampled at the sequence defined rate and length could be stored in a Vantage software receive buffer and loaded into the system software for processing.
Please describe the documentation that is provided for customers.
Dr. Daigle: The Vantage software is extensively documented. The primary documentation for programming the system consists of the Sequence Programming Manual and the Sequence Programming Tutorial. A separate User Manual details setup and operation of the system, and numerous other documents describe tools and unique features of the software. For the most part, they are accessible to users when they download our software.
Do you include any sample programs to help new users get started?
Dr. Daigle: Over 700 example scripts are provided with the software for programming various transducer types for a variety of scanning methods. Many transducers have high image quality example scripts that can be used to obtain diagnostic quality images. All of these examples can be used as provided, or can be modified by the user to develop new techniques.
How easy is it to modify the software to allow for novel applications and unique requirements?
Dr. Daigle: The Vantage software allows full control over all aspects of the ultrasound system. There is a learning curve for programming the system, which is more easily managed by someone familiar with the MATLAB language, the workings of an ultrasound system and how signals from the transducer are acquired and processed. The object-oriented approach to programming considerably shortens this learning curve, allowing the user to focus on the desired characteristics of processing, rather than on programming details of the hardware and software. In addition, a number of software tools written in MATLAB are provided to help the developer analyze their data acquisition control scripts, and to visualize programmed transmit waveforms, beam patterns and the acquired data.
If I want to commercialize my application, can I do so without MATLAB ?
Dr. Daigle: Several researchers have developed breakthrough applications using Vantage and commercialized them. Verasonics licenses its technology to companies, both large and small, for use in their commercial products. We have made several improvements to make it easier for our licensees to replace the MATLAB interface with their own graphical user interface that communicates with our lower-level software. Other researchers have ported their applications for use on other ultrasound systems.