{
  "coordinate_space": "960x640 fitted picture region, original aspect preserved; manual samples ~8px outline / ~24px approximate torso-landmark uncertainty (blur and pose)",
  "curtain": {
    "type": "static projected fabric outline",
    "source_time": 3.8,
    "samples": [
      [
        303.0,
        420.0
      ],
      [
        325.0,
        435.0
      ],
      [
        350.0,
        449.0
      ],
      [
        375.0,
        455.0
      ],
      [
        400.0,
        451.0
      ],
      [
        425.0,
        441.0
      ],
      [
        445.0,
        423.0
      ]
    ],
    "quadratic_coefficients_x_minus_375": [
      -0.006518149381309275,
      0.026420907399263845,
      454.36004197272945
    ],
    "quadratic_vertical_rms_px": 1.185598675345792,
    "catenary_family": {
      "rms_vertical_px": 1.7413700287833715,
      "scale": 800.0,
      "linear_coefficients": [
        -8370.613337889836,
        8825.02355549207
      ]
    },
    "claim": "Neither model identifies a physical law or chain shape; decorative fabric under unknown supports/perspective."
  },
  "diver": {
    "type": "unregistered screen-space approximate torso-landmark positions, not world trajectory",
    "samples_time_xy": [
      [
        1.2,
        596.0,
        282.0
      ],
      [
        1.5,
        614.0,
        276.0
      ],
      [
        1.8,
        624.0,
        240.0
      ],
      [
        2.1,
        556.0,
        212.0
      ],
      [
        2.4,
        534.0,
        226.0
      ],
      [
        2.7,
        484.0,
        220.0
      ],
      [
        3.0,
        452.0,
        234.0
      ],
      [
        3.3,
        444.0,
        276.0
      ]
    ],
    "parametric_quadratic_coefficients": [
      [
        -28.3068783068783,
        35.476190476190396,
        614.8571428571431
      ],
      [
        55.95238095238091,
        -263.6111111111109,
        529.1785714285713
      ]
    ],
    "rms_2d_px": 21.57717323381135,
    "claim": "Camera follows; changing body pose and camera motion invalidate ballistic inference."
  },
  "steel": {
    "type": "projected coil outline",
    "source_time": 0.1,
    "samples": [
      [
        518.0,
        296.0
      ],
      [
        470.0,
        263.0
      ],
      [
        436.0,
        230.0
      ],
      [
        421.0,
        193.0
      ],
      [
        448.0,
        177.0
      ],
      [
        500.0,
        183.0
      ],
      [
        567.0,
        218.0
      ],
      [
        615.0,
        269.0
      ]
    ],
    "quadratic_coefficients_x_minus_500": [
      -0.001177277685278427,
      0.3356125469511345,
      234.37980959641231
    ],
    "rms_vertical_px": 36.22974363000345,
    "claim": "Single-valued quadratic poorly describes curling material; not a measured helix or parabola."
  }
}