{
  "id": "t06_ordering",
  "order": 6,
  "tag": "null",
  "eyebrow": "06 \u00b7 Ordering & gates",
  "title": "The full ellipse gate rejects the sampled static pixels",
  "question": "Does motionless ground pass the complete per-window ellipse filter, including its amplitude floor?",
  "finding": "The corrected per-window shape gate accepts 14.3% of pyramid and 12.9% of desert pixels. After the 0.005 px minor-axis floor, the full gate accepts 0.0% and 0.0%. The earlier shuffle comparison is retained as a diagnostic only.",
  "limitations": "One scene per class and 1,500 dependent pixels. Arbitrary look permutations change correlations between overlapping sub-apertures, so the shuffle statistic is not a calibrated physical null test. The new independent-scene controls replace it as the primary null comparison. Shape-only acceptance is not a false positive of the full gate; sensitivity must also be tested on physical positives.",
  "method": "For each of 26 contiguous W25 windows, choose the best ellipse mode from 1\u20136, then apply adjusted R\u00b2 \u2265 0.25, axis ratio \u2265 0.1 and minor axis \u2265 0.005 px. Pixel acceptance requires at least one fully accepted window. Legacy shuffle results use 60 arbitrary order permutations and are descriptive only.",
  "figures": [
    {
      "file": "results/t06_ordering/figs/t06_permutation.png",
      "caption": "<b>Check all parts of a gate.</b> The right panel excludes the amplitude floor; including it rejects all sampled static pixels. The two shuffle panels are historical diagnostics: permutations do not preserve overlapping-look covariance, so their nominal 5% reference is not a validated false-alarm rate. Per-window selection has been corrected and the scene results rerun."
    }
  ],
  "metrics": {
    "frac_perm_significant": {
      "pyramid pixels": 0.052,
      "empty desert": 0.052
    },
    "ellipse_shape_gate_pass": {
      "pyramid pixels": 0.14333333333333334,
      "empty desert": 0.12933333333333333
    },
    "ellipse_shape_gate_pass_shuffled": {
      "pyramid pixels": 0.12133333333333333,
      "empty desert": 0.12333333333333334
    },
    "ellipse_full_gate_pass": {
      "pyramid pixels": 0.0,
      "empty desert": 0.0
    },
    "median_minor_axis_px": {
      "pyramid pixels": 0.00041976938828380074,
      "empty desert": 0.0004554515787950196
    },
    "median_best_ellipse_adjR2": {
      "pyramid pixels": 0.1989118904338385,
      "empty desert": 0.1898702074840315
    },
    "n_pixels": 1500,
    "n_permutations": 60,
    "runtime_s": 310.1640989780426
  },
  "date": "2026-09-20",
  "provenance": {
    "python": "3.11.3",
    "numpy": "2.4.6",
    "source_sha256": "fa82266809b4aa73e698f2f8ecb4315477aab0ff7205fcaa217616d791d717ff"
  }
}