{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2010:QL7KWG7EM6LJT2X7BBQFKXGFST","short_pith_number":"pith:QL7KWG7E","canonical_record":{"source":{"id":"1011.4630","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.med-ph","submitted_at":"2010-11-21T01:56:36Z","cross_cats_sorted":[],"title_canon_sha256":"88119dec8092b175f8fedfedebdc78c2d53c04c2fe205280626179612de35368","abstract_canon_sha256":"e90acca7a525041850098ddb53551db4944dca05cf59ce2641f534dd4c960ca3"},"schema_version":"1.0"},"canonical_sha256":"82feab1be4679699eaff0860555cc594d842416efba80e397124d5dcd678b968","source":{"kind":"arxiv","id":"1011.4630","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1011.4630","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"arxiv_version","alias_value":"1011.4630v1","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1011.4630","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"pith_short_12","alias_value":"QL7KWG7EM6LJ","created_at":"2026-05-18T12:26:12Z"},{"alias_kind":"pith_short_16","alias_value":"QL7KWG7EM6LJT2X7","created_at":"2026-05-18T12:26:12Z"},{"alias_kind":"pith_short_8","alias_value":"QL7KWG7E","created_at":"2026-05-18T12:26:12Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2010:QL7KWG7EM6LJT2X7BBQFKXGFST","target":"record","payload":{"canonical_record":{"source":{"id":"1011.4630","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.med-ph","submitted_at":"2010-11-21T01:56:36Z","cross_cats_sorted":[],"title_canon_sha256":"88119dec8092b175f8fedfedebdc78c2d53c04c2fe205280626179612de35368","abstract_canon_sha256":"e90acca7a525041850098ddb53551db4944dca05cf59ce2641f534dd4c960ca3"},"schema_version":"1.0"},"canonical_sha256":"82feab1be4679699eaff0860555cc594d842416efba80e397124d5dcd678b968","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T02:04:42.944224Z","signature_b64":"WmKozmAFpyJ6VxDhG5Ja46KdnPvA8IpTZYYKi4wFIzkJGwt+lyBk4DCvysyiOnawtwb6gyA58OzQmJdtiq+UBQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"82feab1be4679699eaff0860555cc594d842416efba80e397124d5dcd678b968","last_reissued_at":"2026-05-18T02:04:42.943458Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T02:04:42.943458Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1011.4630","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":"2026-05-18T02:04:42Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"2l2QxhXaayQkPtz/vl38WXwdJfqxAOHzqRe+mnaGQ/lRMcMPJlRAS1VgeirwZATMlfrWff2PM6iEIuvjXvVjAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-01T13:42:09.593194Z"},"content_sha256":"ee68a5943e2823fc66756d4dc1814cf5ab7b27fec0d32b47fc4bda69649e8e6a","schema_version":"1.0","event_id":"sha256:ee68a5943e2823fc66756d4dc1814cf5ab7b27fec0d32b47fc4bda69649e8e6a"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2010:QL7KWG7EM6LJT2X7BBQFKXGFST","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A constrained, total-variation minimization algorithm for low-intensity X-ray CT","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"physics.med-ph","authors_text":"Christer Ullberg, Emil Y. Sidky, Xiaochuan Pan, Yuval Duchin","submitted_at":"2010-11-21T01:56:36Z","abstract_excerpt":"Purpose: We develop an iterative image-reconstruction algorithm for application to low-intensity computed tomography (CT) projection data, which is based on constrained, total-variation (TV) minimization. The algorithm design focuses on recovering structure on length scales comparable to a detector-bin width.\n  Method: Recovering the resolution on the scale of a detector bin, requires that pixel size be much smaller than the bin width. The resulting image array contains many more pixels than data, and this undersampling is overcome with a combination of Fourier upsampling of each projection an"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1011.4630","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":"2026-05-18T02:04:42Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"mSefJFa3Peck8txTeNbWbyV5PyrCCLrUEjcwsX3/YONEMSA91g7v9Hry750somFuXQIx5pZyHSxsCULhSvzbAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-01T13:42:09.593562Z"},"content_sha256":"f5de0e6eae5097f1eda7dfb1a19cd8161f2edb342ca1406acb8209301283c3ef","schema_version":"1.0","event_id":"sha256:f5de0e6eae5097f1eda7dfb1a19cd8161f2edb342ca1406acb8209301283c3ef"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/bundle.json","state_url":"https://pith.science/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/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":"2026-06-01T13:42:09Z","links":{"resolver":"https://pith.science/pith/QL7KWG7EM6LJT2X7BBQFKXGFST","bundle":"https://pith.science/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/bundle.json","state":"https://pith.science/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/state.json","well_known_bundle":"https://pith.science/.well-known/pith/QL7KWG7EM6LJT2X7BBQFKXGFST/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2010:QL7KWG7EM6LJT2X7BBQFKXGFST","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":"e90acca7a525041850098ddb53551db4944dca05cf59ce2641f534dd4c960ca3","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.med-ph","submitted_at":"2010-11-21T01:56:36Z","title_canon_sha256":"88119dec8092b175f8fedfedebdc78c2d53c04c2fe205280626179612de35368"},"schema_version":"1.0","source":{"id":"1011.4630","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1011.4630","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"arxiv_version","alias_value":"1011.4630v1","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1011.4630","created_at":"2026-05-18T02:04:42Z"},{"alias_kind":"pith_short_12","alias_value":"QL7KWG7EM6LJ","created_at":"2026-05-18T12:26:12Z"},{"alias_kind":"pith_short_16","alias_value":"QL7KWG7EM6LJT2X7","created_at":"2026-05-18T12:26:12Z"},{"alias_kind":"pith_short_8","alias_value":"QL7KWG7E","created_at":"2026-05-18T12:26:12Z"}],"graph_snapshots":[{"event_id":"sha256:f5de0e6eae5097f1eda7dfb1a19cd8161f2edb342ca1406acb8209301283c3ef","target":"graph","created_at":"2026-05-18T02:04:42Z","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":"Purpose: We develop an iterative image-reconstruction algorithm for application to low-intensity computed tomography (CT) projection data, which is based on constrained, total-variation (TV) minimization. The algorithm design focuses on recovering structure on length scales comparable to a detector-bin width.\n  Method: Recovering the resolution on the scale of a detector bin, requires that pixel size be much smaller than the bin width. The resulting image array contains many more pixels than data, and this undersampling is overcome with a combination of Fourier upsampling of each projection an","authors_text":"Christer Ullberg, Emil Y. Sidky, Xiaochuan Pan, Yuval Duchin","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.med-ph","submitted_at":"2010-11-21T01:56:36Z","title":"A constrained, total-variation minimization algorithm for low-intensity X-ray CT"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1011.4630","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:ee68a5943e2823fc66756d4dc1814cf5ab7b27fec0d32b47fc4bda69649e8e6a","target":"record","created_at":"2026-05-18T02:04:42Z","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":"e90acca7a525041850098ddb53551db4944dca05cf59ce2641f534dd4c960ca3","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"physics.med-ph","submitted_at":"2010-11-21T01:56:36Z","title_canon_sha256":"88119dec8092b175f8fedfedebdc78c2d53c04c2fe205280626179612de35368"},"schema_version":"1.0","source":{"id":"1011.4630","kind":"arxiv","version":1}},"canonical_sha256":"82feab1be4679699eaff0860555cc594d842416efba80e397124d5dcd678b968","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"82feab1be4679699eaff0860555cc594d842416efba80e397124d5dcd678b968","first_computed_at":"2026-05-18T02:04:42.943458Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T02:04:42.943458Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"WmKozmAFpyJ6VxDhG5Ja46KdnPvA8IpTZYYKi4wFIzkJGwt+lyBk4DCvysyiOnawtwb6gyA58OzQmJdtiq+UBQ==","signature_status":"signed_v1","signed_at":"2026-05-18T02:04:42.944224Z","signed_message":"canonical_sha256_bytes"},"source_id":"1011.4630","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:ee68a5943e2823fc66756d4dc1814cf5ab7b27fec0d32b47fc4bda69649e8e6a","sha256:f5de0e6eae5097f1eda7dfb1a19cd8161f2edb342ca1406acb8209301283c3ef"],"state_sha256":"e49bc5a6a899fb079b5342e250783a0a0bfe83ee7cfb66cdb72d98e8106f479f"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"kG8rh+9MDYMGJKJBFc8QPVRnOhFxnRLjlMD/bH/CeXgacFmMp8XpfcOaiJzd+QAR4jr1AvtK3QRd3KftChGtDQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-01T13:42:09.595726Z","bundle_sha256":"f1d52ad36b17b949017bf29e9d93cfbaf4f960ddba153e5f33026f7fec94a02e"}}