{"artifact_id":"L1-074","layer":"L1","title":"Talbot-Lau Grating Interferometry (X-ray phase-contrast imaging)","domain":"Coherent Imaging","sub_domain":"Grating-based phase and dark-field imaging","physics_fingerprint":{"L_DAG":3.4,"title":"Talbot-Lau Grating Interferometry (X-ray phase-contrast imaging)","domain":"Coherent Imaging","carrier":"x_ray","primitives":["K.transmit.grating","F.propagation.fresnel","L.modulation.analyzer","int.spatial"],"sub_domain":"Grating-based phase and dark-field imaging","noise_model":"shot_poisson","problem_class":"linear_inverse","solution_space":"triplet_2D_fields","difficulty_delta":3,"integration_axis":"temporal","sensing_mechanism":"grating_interferometry"},"observable_profile":{"metric":"phase_PSNR_dB","regime":"Well-conditioned linear Fourier extraction of three contrast channels from K phase-stepped frames (K >= 3 required; K = 8 typical for noise averaging). Stability dominated by grating alignment and vibration; dark-field channel degrades when visibility V < 0.15.","secondary":"darkfield_SNR"},"size_tiers":{"center_spec":{"omega":{"H":1024,"W":1024,"K_steps":8,"V_center":0.3,"E_mean_keV":40.0,"alignment_tilt":0.0,"grating_period_um":4.8,"grating_period_drift":0.0,"photon_count_per_pixel":10000},"input_format":"K_phase_stepped_intensity_frames","problem_class":"grating_phase_contrast_imaging","forward_operator":"talbot_lau_three_grating","epsilon_fn_center":"30.0 dB phase PSNR"},"omega_bounds":{"H":[256,4096],"W":[256,4096],"K_steps":[3,16],"V_center":[0.05,0.6],"E_mean_keV":[10.0,120.0],"alignment_tilt":[0.0,0.02],"grating_period_um":[1.0,10.0],"phase_step_jitter":[0.0,0.1],"grating_period_drift":[0.0,0.05],"source_coherence_loss":[0.0,0.5],"photon_count_per_pixel":[100,1000000]},"epsilon_bounds":{"psnr_db":[18.0,42.0]},"allowed_problem_classes":["grating_phase_contrast_imaging","xray_phase_tomography"],"allowed_omega_dimensions":["H","W","K_steps","grating_period_um","E_mean_keV","V_center","photon_count_per_pixel","grating_period_drift","alignment_tilt","phase_step_jitter","source_coherence_loss"],"allowed_forward_operators":["talbot_lau_three_grating","edge_illumination","moire_deflectometry"]},"hardness_fn":{"type":"epsilon_fn","delta":3,"kappa":400,"metric":"phase_PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0x0ba11dfeb8a6b1207f64364b2c77952da6b41f189d4405907b04d3c6973de6f1","chain_tx_hash":"0xacbb7730764cd90afc9010534172c04ecfbee959079c125f5f74cd721093ab9a","chain_block":41554170}