{"artifact_id":"L1-088","layer":"L1","title":"4D-STEM — pixelated-detector scanning diffraction imaging","domain":"Electron Microscopy","sub_domain":"Momentum-resolved electron ptychography","physics_fingerprint":{"L_DAG":4.5,"title":"4D-STEM — pixelated-detector scanning diffraction imaging","domain":"Electron Microscopy","carrier":"electron","primitives":["L.illumination.convergent_probe","S.scan.raster","L.diffraction","L.modulus_squared","int.spatial"],"sub_domain":"Momentum-resolved electron ptychography","noise_model":"shot_poisson","problem_class":"nonlinear_inverse","solution_space":"complex_2D","difficulty_delta":10,"integration_axis":"angular","sensing_mechanism":"4d_stem_diffraction"},"observable_profile":{"metric":"PSNR_dB","regime":"Existence of the recovered complex 2D 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 ~= 40); probe_aberration dominates the stability cliff; scan_distortion 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":128,"W":128,"kV":200,"N_q":128,"pixel_A":0.3,"dose_e_per_A2":10000,"scan_distortion":0.0,"probe_aberration":0.0,"partial_coherence":1.0},"input_format":"measurement_only","problem_class":"stem_ptychography","forward_operator":"stem_ptychography_forward","epsilon_fn_center":"24.0"},"omega_bounds":{"H":[32,1024],"W":[32,1024],"kV":[60,300],"N_q":[32,1024],"pixel_A":[0.1,2.0],"dose_e_per_A2":[100,100000],"scan_distortion":[0.0,0.05],"probe_aberration":[0.0,0.3],"partial_coherence":[0.6,1.0]},"epsilon_bounds":{"psnr_db":[10.0,40.0]},"allowed_problem_classes":["stem_ptychography"],"allowed_omega_dimensions":["H","W","N_q","pixel_A","kV","dose_e_per_A2","probe_aberration","scan_distortion","partial_coherence","probe_aberration","scan_distortion","detector_gain","partial_coherence"],"allowed_forward_operators":["stem_ptychography_forward"]},"hardness_fn":{"type":"epsilon_fn","delta":10,"kappa":800,"metric":"PSNR_dB"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0x7cd537f25ca9dedbb219a2a693607d677a0daf6fe75a8b693c8b436e3fa150cf","chain_tx_hash":"0x0a49debd1fc8f2593e9823c630231c10af5a8eca5c4863f0cfd0dacee167530b","chain_block":41554184}