Fig 1.
Visualization of a row-column array.
(a) shows N column arrays with N connections, (b) shows N row arrays with N connections, (c) shows the row column arrangement with 2N connections.
Fig 2.
Two-way radiation pattern (i.e. PSF) of a 5 mm × 5 mm, 32 × 32 elements row-column array.
The -6 dB resolution weakens from 0.5 mm in spot size to 0.9 mm as the focusing and scatterer moves from 5 mm to 20 mm away from the aperture. Side lobes can be seen below -30 dB. Side lobe shape is highly influenced by the natural focusing tendency of the row-column beamforming method.
Fig 3.
A flow chart representing the proposed system.
(a) shows the a top level implementation of the CRC-UIS. (b) shows the signal processing unit in more detail.
Fig 4.
Fan beams originating from the ultrasound transducer.
Black squares indicate available readings, white squares indicate absent readings that need to be estimated.
Fig 5.
Visualization of the uncertainty layer within the state-observation model.
This is a 2-D slice of the full 3-D lattice. The layers (from top to bottom) are state, observation, and uncertainty layer.
Fig 6.
Pairwise relationship illustrated in the state-observation-uncertainty model.
The red window shows a clique, and pairwise connectivity of points within that clique is shown in red lines.
Fig 7.
(a) shows the first artificial phantom with 4 cysts of equal size, (b) shows the second phantom with 4 cysts of decreasing size.
Table 1.
Quantitative results for the simulated phantoms.
For both the first and second phantoms, it is clear that CRC-UIS outperforms other system when it comes to PSNR and ENL, with the exception of the first phantom in the fully addressed 2-D array, where PSNR values were close.
Table 2.
Quantitative results for the real phantom.
Similar results to the simulated data tests, where CRC-UIS outperformed the baseline RC system when it comes to SNR and ENL.
Fig 8.
Visual assessment of our proposed CRC-UIS (top center) as opposed to other systems in literature.
The first phantom is shown in (a), CRC-UIS reconstruction is shown in (b), Baseline RC system shown in (c) with a dynamic range of 40 dB, integrated apodization system [7] shown in (d) with a dynamic range of 60 dB, fully addressed 2-D array shown in (e) with a dynamic range of 30 dB, and column-row-parallel system [13] shown in (f) with a dynamic range of 30 dB.
Fig 9.
Visual assessment of our proposed CRC-UIS (top center) as opposed to other systems in literature.
The second phantom is shown in (a), CRC-UIS reconstruction is shown in (b), Baseline RC system shown in (c) with a dynamic range of 40 dB, integrated apodization system [7] shown in (d) with a dynamic range of 60 dB, fully addressed 2-D array shown in (e) with a dynamic range of 30 dB, and column-row-parallel system [13] shown in (f) with a dynamic range of 30 dB.
Fig 10.
Visual assessment of our proposed CRC-UIS (left side) as opposed to the baseline RC system (right side).
CRC-UIS reconstruction shows better noise reduction while maintaining the shape of the phantom. 40 dB is the dynamic range.
Fig 11.
A closer look at the CRC-UIS reconstruction.
The four wire targets (shown in blue, green, yellow and pink) have a more consistent shape and size. They are also more clearly visible. A region in the background (shown in red) shows a better suppression of noise when compared to the one in the baseline RC system reconstruction.
Fig 12.
A closer look at the baseline RC system reconstruction.
Only two of the four wire targets (blue and green) are clearly visible, and they do not have a consistent shape or size. A region in the background (shown in red) shows unsuppressed ringing noise.