{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2017:22SJ73BUKWUCL5IOV2OWAZLIUA","short_pith_number":"pith:22SJ73BU","canonical_record":{"source":{"id":"1705.06079","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2017-05-17T10:33:04Z","cross_cats_sorted":["math.OC"],"title_canon_sha256":"bfda4923fa72067fc2b4e66043b9ef391e99beef4bbf84084fcd7eea187397df","abstract_canon_sha256":"630e1185766957cfa9c99d6b8ad48fb0b7cfc2d759ea3e9bcc2db42becf4d4a5"},"schema_version":"1.0"},"canonical_sha256":"d6a49fec3455a825f50eae9d606568a01c2a4d9f289e449f104ea176963a7956","source":{"kind":"arxiv","id":"1705.06079","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1705.06079","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"arxiv_version","alias_value":"1705.06079v1","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1705.06079","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"pith_short_12","alias_value":"22SJ73BUKWUC","created_at":"2026-05-18T12:30:55Z"},{"alias_kind":"pith_short_16","alias_value":"22SJ73BUKWUCL5IO","created_at":"2026-05-18T12:30:55Z"},{"alias_kind":"pith_short_8","alias_value":"22SJ73BU","created_at":"2026-05-18T12:30:55Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2017:22SJ73BUKWUCL5IOV2OWAZLIUA","target":"record","payload":{"canonical_record":{"source":{"id":"1705.06079","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2017-05-17T10:33:04Z","cross_cats_sorted":["math.OC"],"title_canon_sha256":"bfda4923fa72067fc2b4e66043b9ef391e99beef4bbf84084fcd7eea187397df","abstract_canon_sha256":"630e1185766957cfa9c99d6b8ad48fb0b7cfc2d759ea3e9bcc2db42becf4d4a5"},"schema_version":"1.0"},"canonical_sha256":"d6a49fec3455a825f50eae9d606568a01c2a4d9f289e449f104ea176963a7956","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:20:17.183374Z","signature_b64":"uqZBMnuy8xI1hIjjR04dWg0cg1qvqHGlelcENfuFD/lOPQJBDcTvfvxQPaVPOIYs6SdyiV9RVuG8rQos29y7Dw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"d6a49fec3455a825f50eae9d606568a01c2a4d9f289e449f104ea176963a7956","last_reissued_at":"2026-05-18T00:20:17.182696Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:20:17.182696Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1705.06079","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:20:17Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"8u2dbggDuMFgL+ggJ0G9ZCo+9RYZ30GVmp+rDVc8o2+AxhzY8KZtkwJHPfuqAOLGa93M+BiMyB/ps4ZHfbkTDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-11T19:56:44.802243Z"},"content_sha256":"c77860bb8052640f57ce55051eaf52186a3d485af289b353a776ba71bd7183d2","schema_version":"1.0","event_id":"sha256:c77860bb8052640f57ce55051eaf52186a3d485af289b353a776ba71bd7183d2"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2017:22SJ73BUKWUCL5IOV2OWAZLIUA","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A Variational Reconstruction Method for Undersampled Dynamic X-ray Tomography based on Physical Motion Models","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["math.OC"],"primary_cat":"math.NA","authors_text":"Andreas Hauptmann, Hendrik Dirks, Lena Frerking, Martin Burger, Samuli Siltanen, Tapio Helin","submitted_at":"2017-05-17T10:33:04Z","abstract_excerpt":"In this paper we study the reconstruction of moving object densities from undersampled dynamic X-ray tomography in two dimensions. A particular motivation of this study is to use realistic measurement protocols for practical applications, i.e. we do not assume to have a full Radon transform in each time step, but only projections in few angular directions. This restriction enforces a space-time reconstruction, which we perform by incorporating physical motion models and regularization of motion vectors in a variational framework. The methodology of optical flow, which is one of the most common"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1705.06079","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:20:17Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"IAyGAyjD9pJPJ14YkhnDlyVurwWi4hGTSWvOr5uwNNnFcaYxYhdJz57OIDyGhF0SRkumRdVeZ//cECNPnQ7kDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-11T19:56:44.802690Z"},"content_sha256":"3b70721ce82dd765f0f613878b6c6039d27c8b0871e6f705cce12ff9d4bc60af","schema_version":"1.0","event_id":"sha256:3b70721ce82dd765f0f613878b6c6039d27c8b0871e6f705cce12ff9d4bc60af"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/bundle.json","state_url":"https://pith.science/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-06-11T19:56:44Z","links":{"resolver":"https://pith.science/pith/22SJ73BUKWUCL5IOV2OWAZLIUA","bundle":"https://pith.science/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/bundle.json","state":"https://pith.science/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/state.json","well_known_bundle":"https://pith.science/.well-known/pith/22SJ73BUKWUCL5IOV2OWAZLIUA/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2017:22SJ73BUKWUCL5IOV2OWAZLIUA","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"630e1185766957cfa9c99d6b8ad48fb0b7cfc2d759ea3e9bcc2db42becf4d4a5","cross_cats_sorted":["math.OC"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2017-05-17T10:33:04Z","title_canon_sha256":"bfda4923fa72067fc2b4e66043b9ef391e99beef4bbf84084fcd7eea187397df"},"schema_version":"1.0","source":{"id":"1705.06079","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1705.06079","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"arxiv_version","alias_value":"1705.06079v1","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1705.06079","created_at":"2026-05-18T00:20:17Z"},{"alias_kind":"pith_short_12","alias_value":"22SJ73BUKWUC","created_at":"2026-05-18T12:30:55Z"},{"alias_kind":"pith_short_16","alias_value":"22SJ73BUKWUCL5IO","created_at":"2026-05-18T12:30:55Z"},{"alias_kind":"pith_short_8","alias_value":"22SJ73BU","created_at":"2026-05-18T12:30:55Z"}],"graph_snapshots":[{"event_id":"sha256:3b70721ce82dd765f0f613878b6c6039d27c8b0871e6f705cce12ff9d4bc60af","target":"graph","created_at":"2026-05-18T00:20:17Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"In this paper we study the reconstruction of moving object densities from undersampled dynamic X-ray tomography in two dimensions. A particular motivation of this study is to use realistic measurement protocols for practical applications, i.e. we do not assume to have a full Radon transform in each time step, but only projections in few angular directions. This restriction enforces a space-time reconstruction, which we perform by incorporating physical motion models and regularization of motion vectors in a variational framework. The methodology of optical flow, which is one of the most common","authors_text":"Andreas Hauptmann, Hendrik Dirks, Lena Frerking, Martin Burger, Samuli Siltanen, Tapio Helin","cross_cats":["math.OC"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2017-05-17T10:33:04Z","title":"A Variational Reconstruction Method for Undersampled Dynamic X-ray Tomography based on Physical Motion Models"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1705.06079","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:c77860bb8052640f57ce55051eaf52186a3d485af289b353a776ba71bd7183d2","target":"record","created_at":"2026-05-18T00:20:17Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"630e1185766957cfa9c99d6b8ad48fb0b7cfc2d759ea3e9bcc2db42becf4d4a5","cross_cats_sorted":["math.OC"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"math.NA","submitted_at":"2017-05-17T10:33:04Z","title_canon_sha256":"bfda4923fa72067fc2b4e66043b9ef391e99beef4bbf84084fcd7eea187397df"},"schema_version":"1.0","source":{"id":"1705.06079","kind":"arxiv","version":1}},"canonical_sha256":"d6a49fec3455a825f50eae9d606568a01c2a4d9f289e449f104ea176963a7956","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"d6a49fec3455a825f50eae9d606568a01c2a4d9f289e449f104ea176963a7956","first_computed_at":"2026-05-18T00:20:17.182696Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:20:17.182696Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"uqZBMnuy8xI1hIjjR04dWg0cg1qvqHGlelcENfuFD/lOPQJBDcTvfvxQPaVPOIYs6SdyiV9RVuG8rQos29y7Dw==","signature_status":"signed_v1","signed_at":"2026-05-18T00:20:17.183374Z","signed_message":"canonical_sha256_bytes"},"source_id":"1705.06079","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:c77860bb8052640f57ce55051eaf52186a3d485af289b353a776ba71bd7183d2","sha256:3b70721ce82dd765f0f613878b6c6039d27c8b0871e6f705cce12ff9d4bc60af"],"state_sha256":"23ad17dd75db2c722e2e1ad2632fd488d13d5e3754c772d5934587a03cf2813f"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"V6+7oB8CJ9/xE3BJ0O/wVLP61xfPPbfcn0okVC/6/0yOu5IRfU761aSmsx7QN4x7jKrJTP9qyltXHCHqLdDfAQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-11T19:56:44.806219Z","bundle_sha256":"161ddf378f276beecc222f3711b688b9adc8143daccd5e69fa97792cb066e8c4"}}