{"artifact_id":"L1-157","layer":"L1","title":"PET-MR Fusion (molecular + multi-contrast soft tissue)","domain":"Multimodal Fusion","sub_domain":"Simultaneous or sequential PET + multi-contrast MR imaging","physics_fingerprint":{"L_DAG":3.8,"title":"PET-MR Fusion (molecular + multi-contrast soft tissue)","domain":"Multimodal Fusion","carrier":"photon","primitives":["L.mr_multi_contrast","L.pet_activity_map","L.registration","L.attenuation_from_mr","int.spatial"],"sub_domain":"Simultaneous or sequential PET + multi-contrast MR imaging","noise_model":"gaussian","problem_class":"nonlinear_inverse","solution_space":"4D_pet_mr_fused","difficulty_delta":5,"integration_axis":"spatial","sensing_mechanism":"pet_mr_fusion"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered 4D pet mr fused 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 ~= 16); mr_based_attenuation_error dominates the stability cliff; motion_between_scans and the remaining mismatch parameters contribute higher-order bias terms. Additive gaussian thermal/electronic noise 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":256,"W":256,"Z":128,"SNR_dB":22,"truncation":0.0,"motion_between_scans":0.0,"susceptibility_distortion":0.0,"mr_based_attenuation_error":0.0},"input_format":"measurement_only","problem_class":"pet_mr_fusion","forward_operator":"pet_mr_fusion_forward","epsilon_fn_center":"24.0"},"omega_bounds":{"H":128,"W":128,"Z":[32,512],"SNR_dB":[0.0,35.0],"truncation":[0.0,0.3],"motion_between_scans":[0.0,10.0],"susceptibility_distortion":[0.0,0.3],"mr_based_attenuation_error":[0.0,0.3]},"epsilon_bounds":{"psnr_db":[5.0,40.0]},"allowed_problem_classes":["pet_mr_fusion"],"allowed_omega_dimensions":["H","W","Z","mr_based_attenuation_error","motion_between_scans","truncation","susceptibility_distortion","SNR_dB","mr_based_attenuation_error","motion_between_scans","truncation","susceptibility_distortion"],"allowed_forward_operators":["pet_mr_fusion_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":5,"kappa":320,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0xadbe9829004e25702f4a55073114dea1c8b4534c9fe88e7db27e79a6757dfc74","chain_tx_hash":"0xf1449e0212c8dcee45ae95d39c2d02393a7c66c210006488134e9abaf0f4bffd","chain_block":41554241}