We need to choose α1 > 1 for dense part and 0 < α2 < 1 for the sparse part.
The partial sparsity-based reconstruction of the sparse part of the scene is shown in Figure 8a.
The whole thickness of the tephra-bearing ice layer including brighter sparse part is about 20 cm on average.
In so doing, we enable the application of conventional sparse reconstruction schemes to obtain an image of the sparse part of the scene containing the stationary indoor targets.
Partial sparsity implies that the scene being imaged consists of a sparse part and a dense part, with the support of the latter assumed to be known.
where τ q 2, n is the two-way traveling time between the n th antenna and the q2th grid-point of the sparse part.
The quasi-cyclic structure of the sparse part of the parity check matrix can be better exploited to serve the layered structure of the decoding algorithm.
The dense part of the scene, corresponding to the building layout (exterior and interior walls parallel to the array and corners), consisted of 7,196 pixels, while the sparse part of the scene consisted of the remaining 12,285 pixels.
To make the encoding and decoding of LDPC codes in DVB-T2 more efficient, the sparse part of the parity check matrix is designed to be in a quasi-cyclic form [25, 26].
Finally, standard l1 norm image reconstruction was performed on the wall clutter mitigated full frequency recovered data to form an image of the sparse part of the scene, shown in Figure 8b.
