  Research in ultrasound imaging is limited in reproducibility by two factors:
First, many existing ultrasound pipelines are protected by intellectual
property, rendering exchange of code difficult. Second, most pipelines are
implemented in special hardware, resulting in limited flexibility of
implemented processing steps on such platforms.
  Methods: With SUPRA we propose an open-source pipeline for fully Software
Defined Ultrasound Processing for Real-time Applications to alleviate these
problems. Covering all steps from beamforming to output of B-mode images, SUPRA
can help improve the reproducibility of results and make modifications to the
image acquisition mode accessible to the research community. We evaluate the
pipeline qualitatively, quantitatively, and regarding its run-time.
  Results: The pipeline shows image quality comparable to a clinical system and
backed by point-spread function measurements a comparable resolution. Including
all processing stages of a usual ultrasound pipeline, the run-time analysis
shows that it can be executed in 2D and 3D on consumer GPUs in real-time.
  Conclusions: Our software ultrasound pipeline opens up the research in image
acquisition. Given access to ultrasound data from early stages (raw channel
data, radiofrequency data) it simplifies the development in imaging.
Furthermore, it tackles the reproducibility of research results, as code can be
shared easily and even be executed without dedicated ultrasound hardware.
