Iterative reconstruction process
AssigneeCarestream Health, Inc.
InventorRichard A. Simon
Life of this patent
Estimating the term…
Abstract
An iterative algorithmic method determines spatial distribution of attenuation values of an object based on measured projection data of the object. An algorithm generates estimated projection data based on an estimated spatial distribution of the attenuation values. Correction data is determined based on a difference between the measured projection data and the estimated projection data. Spatially extended correction data is back projected to update the estimated spatial distribution of the attenuation values. The algorithmic iterations continue until a stopping criterion is reached.
Claims19
A method of determining a three dimensional spatial distribution of attenuation values of an object, the method comprising:
- obtaining an estimate of the spatial distribution of attenuation values;
- capturing a plurality of projection images of the object;
- generating one or more estimated projection images each associated with one of the plurality of captured projection images, the one or more estimated projection images based on the estimate of the spatial distribution of attenuation values;
- generating a correction image for each of the one or more estimated projection images and its associated captured projection image;
- extending each generated correction image along at least one of a column dimension or a row dimension of each generated correction image;
- and
- updating the estimate of the spatial distribution of attenuation values to generate a current estimate of the spatial distribution of attenuation values using the generated extended correction image or images.
A method of determining a spatial distribution of attenuation values of an object, the method comprising:
- obtaining an initial estimate of the spatial distribution of attenuation values of the object;
- capturing a plurality of projection images of the object using an imaging system having a preselected field of view, whereby each captured projection image comprises an associated field of view size;
- iteratively performing the steps of:
- generating one or more estimated projection images using the initial estimate of the spatial distribution of attenuation values once and thereafter using a current estimate of the spatial distribution of attenuation values;
- comparing the one or more estimated projection images with corresponding ones of the captured projection images to generate one or more correction images corresponding to the field of view size;
- extending the one or more generated correction images each along at least one of a column dimension or a row dimension of the one or more generated correction images beyond its corresponding field of view size;
- and
- generating the current estimate of the spatial distribution of attenuation values using the one or more extended correction images.
A method of determining a three dimensional spatial distribution of attenuation values of an object using a radiographic imaging system, the method comprising:
- obtaining an estimate of the spatial distribution of attenuation values;
- capturing a plurality of projection images of the object using two or more x-ray sources each positioned at a different location in the imaging system;
- generating a plurality of estimated projection images each corresponding to one of the captured plurality of projection images using two or more x-ray sources, the plurality of estimated projection images based on the estimate of the spatial distribution of attenuation values;
- generating a correction image for each of the plurality of estimated projection images and their corresponding captured projection images;
- extending each of the plurality of generated correction images along at least one of a column dimension or a row dimension of each of the plurality of generated correction images;
- and
- updating the estimate of the spatial distribution of attenuation values using the extended correction images.
Dependencies are inferred from the claim text.