Abstract: A method of investigating a specimen using tomographic imaging, comprising the steps of providing a specimen and a source, directing a beam of radiation from said source to said specimen, and detecting a flux of radiation transmitted through said specimen. The method further comprises the steps of moving at least one of said specimen and said source for providing relative motion of the source with respect to the specimen; and imaging the specimen along a series of different viewing axes, which intersect a virtual reference surface that surrounds the specimen and is substantially centered thereon, wherein said combined steps of moving and imaging generate a sampling geometry on said virtual reference surface. As defined herein, the steps of moving and imaging are coordinated in such a way that said sampling geometry comprises a plurality of spaced apart line segments.

Abstract: Methods and systems for generation and use of an accelerated tomographic reconstruction preconditioner (ATRP) for accelerated iterative tomographic reconstruction are disclosed. An example method for generating an ATRP for accelerated iterative tomographic reconstruction includes accessing data for a tomography investigation of a sample and determining a trajectory of the tomography investigation of a sample. At least one toy model sample depicting a feature characteristic of the sample are accessed and at least one candidate preconditioner is selected. A first performance of each of the at least one candidate preconditioner on the one or more toy samples is determined, where the candidate preconditioners are then updated to create updated candidate preconditioners. A second performance of each of the updated candidate preconditioners on the one or more toy samples is determined determining. An ATRP is then generated based on at least the first performance and the second performance.

Abstract: A method of investigating a specimen using a tomographic imaging apparatus comprising: A specimen holder, for holding the specimen; A source, for producing a beam of radiation that can be directed at the specimen; A detector, for detecting a flux of radiation transmitted through the specimen from the source; A stage apparatus, for producing relative motion of the source with respect to the specimen, so as to allow the source and detector to image the specimen along a series of different viewing axes; A processing apparatus, for assembling output from the detector into a tomographic image of at least part of the specimen, which method comprises the following steps: Considering a virtual reference surface that surrounds the specimen and is substantially centered thereon; Considering an incoming point of intersection of each of said viewing axes with this reference surface, thereby generating a set of such intersection points corresponding to said series of viewing axes; Choosing discrete viewing axes in sa

Abstract: A method of investigating a specimen using tomographic imaging, comprising the steps of providing a specimen and a source, directing a beam of radiation from said source to said specimen, and detecting a flux of radiation transmitted through said specimen. The method further comprises the steps of moving at least one of said specimen and said source for providing relative motion of the source with respect to the specimen; and imaging the specimen along a series of different viewing axes, which intersect a virtual reference surface that surrounds the specimen and is substantially centered thereon, wherein said combined steps of moving and imaging generate a sampling geometry on said virtual reference surface. As defined herein, the steps of moving and imaging are coordinated in such a way that said sampling geometry comprises a plurality of spaced apart line segments.

Abstract: Methods and apparatuses are disclosed herein to correct for inconsistencies in CT scans based on pi-lines. An example method at least includes acquiring a plurality of projections of a sample, each projection of the plurality of projections acquired at a different location around the sample based on a trajectory, determining pairs of opposing projections from the plurality of projections based on a respective pi-line, and determining an amount of inconsistency between respective pi-line data for each pair of opposing projections, where the pi-line data is based, at least in part, on attenuation data.

Abstract: Apparatuses and methods for implementing scanning trajectories for ROI tomography are disclosed herein. An example method includes determining a first focus object distance based on a circumradius of a sample, the sample including a region of interest, determining a second focus object distance based on a radius of a smallest cylinder that contains the region of interest, determining a plurality of viewing angles from a plurality of possible viewing angles in response to the first focus object distance, where each viewing angle of the plurality of viewing angles has an associated focus object distance measured from the region of interest, and where the associated focus object distance of each of the plurality of viewing angles is less than the first focus object distance and greater than the second focus object distance, and scanning the region of interest using at least the plurality of viewing angles.

Abstract: Methods and apparatuses disclosed herein provide beam hardening correction to tomographic reconstruction using a simplification to the Alvarez-Macovski attenuation model. An example method includes simplifying a forward projection model, the forward projection model based on an Alvarez-Macovski (AM) attenuation model, wherein the simplification of the forward projection model simplifies the AM attenuation model for one of photoelectric effect only, constant density, constant atomic number, and density proportional to atomic number, and performing an iterative reconstruction of a sample using the simplified forward projection model, the iterative reconstruction weighted by a first spectrum, wherein measured image data of the sample used in the iterative reconstruction is obtained at a first energy, and wherein a reverse operation of the iterative reconstruction is a non-adjoint to the simplified forward projection model.

Abstract: Apparatuses and methods for implementing scanning trajectories for ROI tomography are disclosed herein. An example method includes determining a first focus object distance based on a circumradius of a sample, the sample including a region of interest, determining a second focus object distance based on a radius of a smallest cylinder that contains the region of interest, determining a plurality of viewing angles from a plurality of possible viewing angles in response to the first focus object distance, where each viewing angle of the plurality of viewing angles has an associated focus object distance measured from the region of interest, and where the associated focus object distance of each of the plurality of viewing angles is less than the first focus object distance and greater than the second focus object distance, and scanning the region of interest using at least the plurality of viewing angles.

Abstract: Methods and apparatuses disclosed herein provide beam hardening correction to tomographic reconstruction using a simplification to the Alvarez-Macovski attenuation model. An example method includes simplifying a forward projection model, the forward projection model based on an Alvarez-Macovski (AM) attenuation model, wherein the simplification of the forward projection model simplifies the AM attenuation model for one of photoelectric effect only, constant density, constant atomic number, and density proportional to atomic number, and performing an iterative reconstruction of a sample using the simplified forward projection model, the iterative reconstruction weighted by a first spectrum, wherein measured image data of the sample used in the iterative reconstruction is obtained at a first energy, and wherein a reverse operation of the iterative reconstruction is a non-adjoint to the simplified forward projection model.

Abstract: Methods and apparatuses are disclosed herein to correct for inconsistencies in CT scans based on pi-lines. An example method at least includes acquiring a plurality of projections of a sample, each projection of the plurality of projections acquired at a different location around the sample based on a trajectory, determining pairs of opposing projections from the plurality of projections based on a respective pi-line, and determining an amount of inconsistency between respective pi-line data for each pair of opposing projections, where the pi-line data is based, at least in part, on attenuation data.

Abstract: A method of investigating a specimen using a tomographic imaging apparatus comprising: A specimen holder, for holding the specimen; A source, for producing a beam of radiation that can be directed at the specimen; A detector, for detecting a flux of radiation transmitted through the specimen from the source; A stage apparatus, for producing relative motion of the source with respect to the specimen, so as to allow the source and detector to image the specimen along a series of different viewing axes; A processing apparatus, for assembling output from the detector into a tomographic image of at least part of the specimen, which method comprises the following steps: Considering a virtual reference surface that surrounds the specimen and is substantially centered thereon; Considering an incoming point of intersection of each of said viewing axes with this reference surface, thereby generating a set of such intersection points corresponding to said series of viewing axes; Choosing discrete viewing axes in sa

Abstract: A method of investigating a specimen using a tomographic imaging apparatus using a stage for producing relative motion of a source with respect to a specimen, so as to allow the source and a detector to image the specimen along a series of different viewing axes and a processing apparatus for assembling a tomographic image of at least part of the specimen. The investigation is carried out by considering a virtual reference surface that surrounds the specimen and is substantially centered thereon, considering an incoming point of intersection of each of said viewing axes with this reference surface, thereby generating a set of such intersection points corresponding to the series of viewing axes, choosing discrete viewing axes in the series so as to cause the set to comprise a two-dimensional lattice of points located areally on the reference surface in a substantially uniform distribution.

Abstract: OCT imaging systems are provided for imaging a spherical-type eye including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path. The reference arm path has an associated reference arm path length. A sample is also provided having an associated sample arm path coupled to the source arm and reference arm paths. A lens having a focal power optimized for a diameter of the spherical-type eye is provided along with a reference arm path length adjustment module coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference arm path length is based on an eye diameter of the subject.

Abstract: A method of investigating a specimen using a tomographic imaging apparatus, by performing, in multiple iterations, the following steps: (i) Using a Back Projection technique to produce an initial tomogram from a set of initial images; (ii) Subjecting said initial tomogram to a mathematical filtering operation, thereby producing an adjusted tomogram; (iii) Using a Forward Projection technique on said adjusted tomogram to dissociate it into a set of calculated images; (iv) Repeating steps (i)-(iii) until said calculated images satisfy an acceptance criterion.

Abstract: OCT imaging systems are provided for imaging a spherical-type eye including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path. The reference arm path has an associated reference arm path length. A sample is also provided having an associated sample arm path coupled to the source arm and reference arm paths. A lens having a focal power optimized for a diameter of the spherical-type eye is provided along with a reference arm path length adjustment module coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference arm path length is based on an eye diameter of the subject.

Abstract: OCT imaging systems are provided for imaging a spherical-type eye including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path. The reference arm path has an associated reference arm path length. A sample is also provided having an associated sample arm path coupled to the source arm and reference arm paths. A lens having a focal power optimized for a diameter of the spherical-type eye is provided along with a reference arm path length adjustment module coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference arm path length is based on an eye diameter of the subject.

Abstract: OCT imaging systems are provided for imaging a spherical-type eye including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path. The reference arm path has an associated reference arm path length. A sample is also provided having an associated sample arm path coupled to the source arm and reference arm paths. A lens having a focal power optimized for a diameter of the spherical-type eye is provided along with a reference arm path length adjustment module coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference arm path length is based on an eye diameter of the subject.

Abstract: OCT imaging systems are provided for imaging a spherical-type eye including a source having an associated source arm path and a reference arm having an associated reference arm path coupled to the source path. The reference arm path has an associated reference arm path length. A sample is also provided having an associated sample arm path coupled to the source arm and reference arm paths. A lens having a focal power optimized for a diameter of the spherical-type eye is provided along with a reference arm path length adjustment module coupled to the reference arm. The reference arm path length adjustment module is configured to automatically adjust the reference arm path length such that the reference arm path length is based on an eye diameter of the subject.

Abstract: A method of investigating a specimen using a tomographic imaging apparatus comprising: A specimen holder, for holding the specimen; A source, for producing a beam of radiation that can be directed at the specimen; A detector, for detecting a flux of radiation transmitted through the specimen from the source; A stage apparatus, for producing relative motion of the source with respect to the specimen, so as to allow the source and detector to image the specimen along a series of different viewing axes; A processing apparatus, for performing a mathematical reconstruction step whereby output from the detector is compiled into a tomographic image of at least part of the specimen, wherein said reconstruction step is performed in multiple iterations, which comprise the following steps: (i) Using a Back Projection technique to produce an initial tomogram from a set of initial images; (ii) Subjecting said initial tomogram to a mathematical filtering operation, thereby producing an adjusted tomogram; (iii) Using a

Abstract: A method of investigating a specimen using a tomographic imaging apparatus using a stage for producing relative motion of a source with respect to a specimen, so as to allow the source and a detector to image the specimen along a series of different viewing axes and a processing apparatus for assembling a tomographic image of at least part of the specimen. The investigation is carried out by considering a virtual reference surface that surrounds the specimen and is substantially centered thereon, considering an incoming point of intersection of each of said viewing axes with this reference surface, thereby generating a set of such intersection points corresponding to the series of viewing axes, choosing discrete viewing axes in the series so as to cause the set to comprise a two-dimensional lattice of points located areally on the reference surface in a substantially uniform distribution.