Patent ID: 11940508
Assignee: BEIJING UNIVERSITY OF AERONAUTICS AND ASTRONAUTICS
Field: Measurement (Instruments)
Classification: CPC G  A | IPC A  G

Claim 8:
9. The MPI and FMT-fused multimodal imaging method for the small animal according to claim 8, wherein the operation of solving the least squares problem with the L1 norm constraint through the oblique projection matching pursuit method, thereby acquiring the 3D structural fluorescence distribution of the lesion region in the body of the target object comprises:
performing a pre-selection process: selecting a node with an intensity greater than a set intensity threshold from the surface fluorescence signal Φ; adding the node to a pre-constructed pre-selected set Et; and calculating an oblique projection operator and a complementary projection operator of each node in the pre-selected set;
wherein, the oblique projection operator and the complementary projection operator are expressed as follows:

PEt=AEtAEt+

PEt⊥=I−PEt

wherein AEt denotes a column corresponding to the pre-selected set Et in the system matrix A; AEt+ denotes a pseudo inverse of AEt; PEt denotes the oblique projection operator in span(AEt); PEt⊥ denotes the complementary projection operator in an orthogonal complementary space of span(AEt); and I denotes an identity matrix;
performing a cyclic iteration process: selecting a column with a strongest correlation with a residual of a previous iteration among remaining columns in the system matrix A, and adding a number of the selected column to a support set T, wherein the correlation is calculated by an inner product of the column and the residual; and the support set comprises some column elements that meet a condition in the system matrix, and is set as an empty matrix before a first iteration; and
calculating, based on the support set, a temporary solution X and a residual rk:

X=(PEt⊥AT)†)  (1)

rk=Φ−ATX 

wherein, AT denotes an expansion of elements in the system matrix A corresponding to the support set before a current iteration; and
exiting the iteration when the residual of the current iteration is less than a preset threshold E; and outputting the temporary solution and the support set for the current iteration.