Hohage, Thorsten

[["dc.bibliographiccitation.firstpage","11552"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","11569"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Robisch, Anna-Lena"],["dc.contributor.author","Luke, D. R."],["dc.contributor.author","Homann, C."],["dc.contributor.author","Hohage, Thorsten"],["dc.contributor.author","Cloetens, Peter"],["dc.contributor.author","Suhonen, H."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2017-09-07T11:46:15Z"],["dc.date.available","2017-09-07T11:46:15Z"],["dc.date.issued","2014"],["dc.description.abstract","We illustrate the errors inherent in the conventional empty beam correction of full field X-ray propagation imaging, i.e. the division of intensities in the detection plane measured with an object in the beam by the intensity pattern measured without the object, i.e. the empty beam intensity pattern. The error of this conventional approximation is controlled by the ratio of the source size to the smallest feature in the object, as is shown by numerical simulation. In a second step, we investigate how to overcome the flawed empty beam division by simultaneous reconstruction of the probing wavefront (probe) and of the object, based on measurements in several detection planes (multi-projection approach). The algorithmic scheme is demonstrated numerically and experimentally, using the defocus wavefront of the hard X-ray nanoprobe setup at the European Synchrotron Radiation Facility (ESRF). (C) 2014 Optical Society of America"],["dc.identifier.doi","10.1364/OE.22.011552"],["dc.identifier.fs","604845"],["dc.identifier.gro","3142122"],["dc.identifier.isi","000336957700017"],["dc.identifier.pmid","24921276"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12635"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/4789"],["dc.language.iso","en"],["dc.notes.intern","WoS Import 2017-03-10 / Funder: [SFB 755]"],["dc.notes.intern","Merged from goescholar"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Institut für Numerische und Angewandte Mathematik"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Fakultät für Mathematik und Informatik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.gro","x-ray imaging"],["dc.title","Reconstruction of wave front and object for inline holography from a set of detection planes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","6490"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","6506"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Maretzke, Simon"],["dc.contributor.author","Bartels, Matthias"],["dc.contributor.author","Krenkel, Martin"],["dc.contributor.author","Salditt, Tim"],["dc.contributor.author","Hohage, Thorsten"],["dc.date.accessioned","2017-09-07T11:54:34Z"],["dc.date.available","2017-09-07T11:54:34Z"],["dc.date.issued","2016"],["dc.description.abstract","Like many other advanced imaging methods, x-ray phase contrast imaging and tomography require mathematical inversion of the observed data to obtain real-space information. While an accurate forward model describing the generally nonlinear image formation from a given object to the observations is often available, explicit inversion formulas are typically not known. Moreover, the measured data might be insufficient for stable image reconstruction, in which case it has to be complemented by suitable a priori information. In this work, regularized Newton methods are presented as a general framework for the solution of such ill-posed nonlinear imaging problems. For a proof of principle, the approach is applied to x-ray phase contrast imaging in the near-field propagation regime. Simultaneous recovery of the phase-and amplitude from a single near-field diffraction pattern without homogeneity constraints is demonstrated for the first time. The presented methods further permit all-at-once phase contrast tomography, i.e. simultaneous phase retrieval and tomographic inversion. We demonstrate the potential of this approach by three-dimensional imaging of a colloidal crystal at 95nm isotropic resolution. (C) 2016 Optical Society of America"],["dc.identifier.doi","10.1364/OE.24.006490"],["dc.identifier.gro","3141708"],["dc.identifier.isi","000373395700102"],["dc.identifier.pmid","27136840"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/13243"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/191"],["dc.notes.intern","WoS Import 2017-03-10"],["dc.notes.intern","Merged from goescholar"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","PUB_WoS_Import"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Institut für Numerische und Angewandte Mathematik"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.subject.gro","x-ray imaging"],["dc.title","Regularized Newton methods for x-ray phase contrast and general imaging problems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","013821"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Physical Review. A"],["dc.bibliographiccitation.lastpage","10"],["dc.bibliographiccitation.volume","91"],["dc.contributor.author","Homann, C."],["dc.contributor.author","Hohage, Thorsten"],["dc.contributor.author","Hagemann, J."],["dc.contributor.author","Robisch, A.-L."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2015-01-29T09:09:40Z"],["dc.date.accessioned","2021-10-11T11:36:16Z"],["dc.date.available","2015-01-29T09:09:40Z"],["dc.date.available","2021-10-11T11:36:16Z"],["dc.date.issued","2015"],["dc.description.abstract","Extended wavefronts are used for coherent full field imaging of objects based on solving the inverse Fresnel diffraction problem. To this end, the conventional data correction step is given by division of the recorded object image by the intensity pattern of the empty beam. This division of intensities in the detection plane is a rather crude approximation for the separation of the complex valued object and probing fields. Here we present a quantitative error estimate, along with its mathematical proof, and confirm the prediction with numerical simulations. Finally the problem is illustrated with experimental results."],["dc.identifier.doi","10.1103/PhysRevA.91.013821"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11553"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/90770"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1094-1622"],["dc.relation.issn","1050-2947"],["dc.relation.orgunit","Fakultät für Physik"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 3.0"],["dc.rights.access","openAccess"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0/"],["dc.subject","empty-beam correction; near-field imaging; Validity"],["dc.subject.gro","x-ray imaging"],["dc.title","Validity of the empty-beam correction in near-field imaging"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]