{"artifact_id":"L1-045","layer":"L1","title":"Diffusion MRI (DWI / DTI / HARDI)","domain":"Medical Imaging","sub_domain":"Water-diffusion-weighted MRI for microstructure/tractography","physics_fingerprint":{"L_DAG":3.8,"title":"Diffusion MRI (DWI / DTI / HARDI)","domain":"Medical Imaging","carrier":"radio_wave","primitives":["L.rf_excitation","L.diffusion_gradient","L.gradient_encoding","int.angular"],"sub_domain":"Water-diffusion-weighted MRI for microstructure/tractography","noise_model":"gaussian","problem_class":"nonlinear_inverse","solution_space":"4D_diffusion_tensor_or_ODF","difficulty_delta":5,"integration_axis":"angular","sensing_mechanism":"mri_fourier_encoding"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered 4D diffusion tensor or ODF 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 ~= 18); eddy_currents dominates the stability cliff; motion 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":128,"W":128,"Z":64,"SNR_dB":20,"motion":0.0,"N_directions":32,"B0_distortion":0.0,"eddy_currents":0.0,"b_max_s_per_mm2":1000,"partial_volume_CSF":0.0},"input_format":"measurement_only","problem_class":"dmri","forward_operator":"dmri_forward","epsilon_fn_center":"20.0"},"omega_bounds":{"H":64,"W":64,"Z":[16,256],"SNR_dB":[0.0,35.0],"motion":[0.0,0.5],"N_directions":[6,256],"B0_distortion":[0.0,0.3],"eddy_currents":[0.0,0.3],"b_max_s_per_mm2":[100,5000],"partial_volume_CSF":[0.0,0.3]},"epsilon_bounds":{"psnr_db":[5.0,45.0]},"allowed_problem_classes":["dmri"],"allowed_omega_dimensions":["H","W","Z","N_directions","b_max_s_per_mm2","SNR_dB","eddy_currents","motion","B0_distortion","partial_volume_CSF","eddy_currents","motion","B0_distortion","partial_volume_CSF"],"allowed_forward_operators":["dmri_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":5,"kappa":360,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0x86eda8fa6529b40c56bdcd45721d0f846b0e76b9d5a8f82f08800d56b1b062c1","chain_tx_hash":"0xae0121d4d4c450e698d264aa07d0cf545572f1c42e70b0f483a4a3c3ea2da7b9","chain_block":41552301}