摘要:
A method is provided for reconstructing an image of an object that includes image elements. The method includes accessing measurement data associated with the image elements, introducing an auxiliary variable to transform an original problem of reconstructing the image to a constrained optimization problem, and solving the constrained optimization problem using a method of multipliers to create a sequence of sub-problems and solve the sequence of sub-problems. Solving the sequence of sub-problems includes reconstructing the image by optimizing a first objective function. The first objective function is optimized by iteratively solving a nested sequence of approximate optimization problems. An inner loop iteratively optimizes a second objective function approximating the first objective function. An outer loop utilizes the solution of the second objective function to optimize the first objective function.
摘要:
A method is provided for reconstructing an image of an object that includes image elements. The method includes accessing measurement data associated with the image elements, introducing an auxiliary variable to transform an original problem of reconstructing the image to a constrained optimization problem, and solving the constrained optimization problem using a method of multipliers to create a sequence of sub-problems and solve the sequence of sub-problems. Solving the sequence of sub-problems includes reconstructing the image by optimizing a first objective function. The first objective function is optimized by iteratively solving a nested sequence of approximate optimization problems. An inner loop iteratively optimizes a second objective function approximating the first objective function. An outer loop utilizes the solution of the second objective function to optimize the first objective function.
摘要:
A method is provided for iteratively reconstructing an image of an object. The method includes accessing measurement data associated with the image, and using a simultaneous algorithm to reconstruct the image. Using the simultaneous algorithm to reconstruct the image includes determining a scaling factor that is voxel-dependent, and applying the voxel-dependent scaling factor to a gradient of an objective function to reconstruct the image.
摘要:
A method is provided for iteratively reconstructing an image of an object. The method includes accessing measurement data associated with the image, and using a simultaneous algorithm to reconstruct the image. Using the simultaneous algorithm to reconstruct the image includes determining a scaling factor that is voxel-dependent, and applying the voxel-dependent scaling factor to a gradient of an objective function to reconstruct the image.
摘要:
A method for reconstructing an image of an object that includes a plurality of image elements. The method includes accessing image data associated with a plurality of image elements, and reconstructing an image of the object by optimizing an objective function, where the objective function is optimized by iteratively solving a nested sequence of approximate optimization problems. The algorithm is composed of nested iterative loops, in which an inner loop iteratively optimizes an objective function approximating the outer loop objective function, and an outer loop that utilizes the solution of the inner loop to optimize the original objective function.
摘要:
A method for reconstructing an image of an object that includes a plurality of image elements. The method includes accessing image data associated with a plurality of image elements, and reconstructing an image of the object by optimizing an objective function, where the objective function is optimized by iteratively solving a nested sequence of approximate optimization problems. The algorithm is composed of nested iterative loops, in which an inner loop iteratively optimizes an objective function approximating the outer loop objective function, and an outer loop that utilizes the solution of the inner loop to optimize the original objective function.
摘要:
Methods are provided for iteratively reconstructing an image signal to generate a reconstructed image signal. In one embodiment, sub-iterations of each iteration are performed on pixel or voxel subsets. The subsets may be composed of neighboring or spatially separated pixel or voxels and may extend in the z-direction. In one embodiment, an update step of the iterative reconstruction involves the direct inversion of an approximation of a Hessian matrix associated with the respective subsets. In further embodiments, non-negativity or other limitations or constraints on update values may be enforced.
摘要:
The present disclosure is directed to a plasticizer, polymeric compositions containing the plasticizer, and conductors coated with the polymeric composition. The plasticizer includes (i) an epoxidized fatty acid methyl ester, (ii) an epoxidized natural oil, and (iii) an epoxidized tallate ester. Polymeric compositions containing a polymeric resin and the plasticizer exhibit a weight loss less than 50 mg/cm2 after exposure to 100° C. for seven days. Conductors coated with the polymeric composition (containing the plasticizer) pass the low temperature unwind test of UL719 and exhibit a weight loss less than 50 mg/cm2 after exposure to 100° C. for seven days.
摘要翻译:本公开涉及含增塑剂的增塑剂,聚合物组合物和涂覆有聚合物组合物的导体。 增塑剂包括(i)环氧化脂肪酸甲酯,(ii)环氧化天然油,和(iii)环氧化的酯酸酯。 含有聚合物树脂和增塑剂的聚合物组合物在暴露于100℃下显示重量损失小于50mg / cm 2,持续7天。 用聚合物组合物(含增塑剂)涂覆的导体通过UL719的低温退火试验,并且在暴露于100℃下显示出低于50mg / cm 2的重量减少7天。
摘要:
Disclosed is a halogen-free, flame retardant thermoplastic resin composition based on polypropylene and one or more thermoplastic elastomers with an organic nitrogen- and/or phosphorus-based intumescent flame retardant comprising a piperazine component. The composition is processed easily to make a wire and cable sheath exhibiting a balance of high flame retardancy, good flexibility, high wet electrical resistance and excellent heat deformation properties, and which passes the VW-I flame retardancy test, the UL1581 heat deformation test at 150° C. and the wet electrical resistance test, and also exhibits good tensile and flexibility properties. Also disclosed is a wire and cable sheath made from the composition.
摘要:
The present disclosure relates to iterative reconstruction of images. In certain embodiments, a deconvolution filter is used to approximate the inversion of a Hessian matrix associated with the reconstruction. In one such embodiment, the desired image is not reconstructed directly in the iterative process. Instead, an image is reconstructed that yields the desired image when filtered by the deconvolution filter.