Fig. 5.

Maximum amplitude projections of the OA signal of gold wires in water. Raw images (top row), DAS and FD reconstructions (second and third rows) and DAS and FD with coherence factor (fourth and bottom rows) at various z-positions: at the focal plane (left column), at 250 μm and at 750 μm below the acoustic focal plane. The dotted line indicates the critical B-scan with the corresponding intensity profile below. The uneven intensity of the wires is likely attributed to uneven dust adhered to on the gold wire surface.