Figure 4

Resolution maps and wire phantom images collected for the freehand OpUS probe. (a) Lateral resolution map. (b) Axial resolution map, (a,b presented on the same color scale). (c) Measured resolutions along the lateral centre of the imaging plane (marked on (a and b)). (d) DaS-reconstructed, freehand OpUS image of a single tungsten wire (diameter: 27 µm, acting as a point scatterer) located approximately centrally in the imaging plane, collected at 3 averages. (e) DaS-reconstructed, freehand OpUS image of fifteen tungsten wires (diameter: 15 µm) arranged at 2 mm intervals to 30 mm imaging depth. (d) and (e) are presented on the same logarithmic scale.