{"artifact_id":"L1-054","layer":"L1","title":"Photon-Counting CT (PCCT) — spectral detector CT","domain":"Medical Imaging","sub_domain":"Energy-resolved direct-conversion CT","physics_fingerprint":{"L_DAG":4.5,"title":"Photon-Counting CT (PCCT) — spectral detector CT","domain":"Medical Imaging","carrier":"x_ray","primitives":["L.xray_source","S.scan.angular","D.pcd_detector","L.spectral_decompose","L.backproject","int.angular"],"sub_domain":"Energy-resolved direct-conversion CT","noise_model":"shot_poisson","problem_class":"nonlinear_inverse","solution_space":"3D_material_decomposition","difficulty_delta":10,"integration_axis":"angular","sensing_mechanism":"photon_counting_ct"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered 3D material decomposition is guaranteed within the declared Omega bounds. Uniqueness is local rather than global (non-convex landscape); convergence depends on initialisation and priors. Stability is moderately conditioned (kappa_eff ~= 25); charge_sharing dominates the stability cliff; pulse_pileup and the remaining mismatch parameters contribute higher-order bias terms. Photon-shot-noise-limited (poisson counting) sets the irreducible data-fidelity floor, while TV / wavelet-sparsity / deep priors stabilise recovery at the ill-conditioned end of Omega.","secondary":"SSIM"},"size_tiers":{"center_spec":{"omega":{"H":512,"W":512,"Z":256,"mAs":100,"pixel_mm":0.25,"pulse_pileup":0.0,"N_energy_bins":5,"N_projections":720,"beam_hardening":0.0,"charge_sharing":0.05,"k_edge_calibration":0.0},"input_format":"measurement_only","problem_class":"pcct","forward_operator":"pcct_forward","epsilon_fn_center":"28.0"},"omega_bounds":{"H":256,"W":256,"Z":[64,2048],"mAs":[1,500],"pixel_mm":[0.05,1.0],"pulse_pileup":[0.0,0.5],"N_energy_bins":[2,16],"N_projections":[180,2880],"beam_hardening":[0.0,0.3],"charge_sharing":[0.0,0.3],"k_edge_calibration":[0.0,0.1]},"epsilon_bounds":{"psnr_db":[5.0,45.0]},"allowed_problem_classes":["pcct"],"allowed_omega_dimensions":["H","W","Z","N_projections","N_energy_bins","mAs","pixel_mm","charge_sharing","pulse_pileup","beam_hardening","k_edge_calibration","charge_sharing","pulse_pileup","beam_hardening","k_edge_calibration"],"allowed_forward_operators":["pcct_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":10,"kappa":500,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0xf3a17a4cef566a2d434a04aa0a839ae9bcb8d1f11af8cd9ef236ef70d4e7d136","chain_tx_hash":"0x2af601a4544eeb51a482ce435bb1dca49cdf0af5b543684bd5a39809d06724ec","chain_block":41553359}