A real-time realization of an automatic dynamic range adjustment method on a smart mobile device for point-of-care ultrasound imaging

Dynamic range (DR) is one of the most essential parameters that determine the image quality and feature representation in ultrasound B-mode imaging. Thus, the automatic DR adjustment (ADRA) method was previously proposed for reducing user dependency and improving image quality. In this paper, for a smart phone based point-of-care ultrasound imaging system, the real-time realization of the ADRA method on a smart phone using a mobile GPU is presented. The ADRA method was implemented on the NEXUS 4 running on the Android 4.3 by utilizing the several graphics pipelines supported from the OpenGL ES platform. For evaluating the real-time ADRA method, 200 frames of in vivo abdominal data were acquired by a 3.5-MHz convex array transducer from with a commercial ultrasound scanner equipped with a research package (Accuvix V10, Samsung Medison, Seoul, Korea). The GPU-based ADRA method showed the enhanced contrast-to-noise ratio (CNR) compared to the conventional method with a fixed DR value, i.e., 3.89±0.71 vs. 3.35±0.88, respectively. In addition, it showed a higher frame rate (i.e., >60 frames/sec) compared to the CPU-based ADRA method while providing the comparable CNR value. These results indicate that the ADRA method can be successfully supported in the smartphone while improving the image quality with less user dependency.