{
  "metric": "Mean absolute RGB channel difference, 0..255; lower means smaller pixel color difference in this ROI. Not global similarity or percent.",
  "reference": "https://pub-236dc9dc170e487faec4c8b5e2d084c6.r2.dev/pages/seosoyoung-vtuber-front/sunburst-r1/reference-v1.png",
  "assembly": "assembled-crop-parts-v2.png",
  "assemblySha256": "1fbf123b7062fb5eea5894860437ca4a9a4ffdcffab6f57f2effd17eb8add4ec",
  "coordinateSystem": "original 1024x1536 canvas, no alignment/color adjustment",
  "regions": [
    {
      "region": "cheek_l",
      "sourceROI": [
        395,
        486,
        423,
        516
      ],
      "pixelCount": 840,
      "oldR6RgbMAE": 17.793650793650794,
      "generatedFaceOnlyRgbMAE": 3.096825396825397,
      "finalAssemblyRgbMAE": 4.3087301587301585,
      "finalMeanSignedRgbDifference": [
        -1.0023809523809524,
        -2.2035714285714287,
        -0.9678571428571429
      ],
      "referenceMask": "all pixels in ROI",
      "caveat": null
    },
    {
      "region": "cheek_r",
      "sourceROI": [
        579,
        486,
        607,
        516
      ],
      "pixelCount": 840,
      "oldR6RgbMAE": 17.365079365079364,
      "generatedFaceOnlyRgbMAE": 2.706746031746032,
      "finalAssemblyRgbMAE": 3.7936507936507935,
      "finalMeanSignedRgbDifference": [
        -0.8297619047619048,
        -1.3773809523809524,
        -0.34523809523809523
      ],
      "referenceMask": "all pixels in ROI",
      "caveat": null
    },
    {
      "region": "lower_cheek_l",
      "sourceROI": [
        437,
        537,
        461,
        564
      ],
      "pixelCount": 648,
      "oldR6RgbMAE": 2.4917695473251027,
      "generatedFaceOnlyRgbMAE": 0.8729423868312757,
      "finalAssemblyRgbMAE": 0.8729423868312757,
      "finalMeanSignedRgbDifference": [
        -0.3888888888888889,
        -0.5216049382716049,
        -1.2669753086419753
      ],
      "referenceMask": "all pixels in ROI",
      "caveat": null
    },
    {
      "region": "lower_cheek_r",
      "sourceROI": [
        547,
        537,
        571,
        564
      ],
      "pixelCount": 648,
      "oldR6RgbMAE": 3.807098765432099,
      "generatedFaceOnlyRgbMAE": 0.6424897119341564,
      "finalAssemblyRgbMAE": 0.6424897119341564,
      "finalMeanSignedRgbDifference": [
        -0.1867283950617284,
        0.08179012345679013,
        -0.46141975308641975
      ],
      "referenceMask": "all pixels in ROI",
      "caveat": null
    },
    {
      "region": "chin",
      "sourceROI": [
        486,
        586,
        516,
        602
      ],
      "pixelCount": 480,
      "oldR6RgbMAE": 1.1722222222222223,
      "generatedFaceOnlyRgbMAE": 0.7909722222222222,
      "finalAssemblyRgbMAE": 0.7909722222222222,
      "finalMeanSignedRgbDifference": [
        -0.5416666666666666,
        -0.54375,
        -0.9208333333333333
      ],
      "referenceMask": "all pixels in ROI",
      "caveat": null
    },
    {
      "region": "forehead_exposed_skin",
      "sourceROI": [
        530,
        300,
        562,
        330
      ],
      "pixelCount": 901,
      "oldR6RgbMAE": 22.98927118017018,
      "generatedFaceOnlyRgbMAE": 1.222345541990381,
      "finalAssemblyRgbMAE": 1.3459119496855345,
      "finalMeanSignedRgbDifference": [
        -0.40288568257491675,
        0.14317425083240842,
        0.146503884572697
      ],
      "referenceMask": "R>240 and R-G>15 and G-B>8 to exclude hair",
      "caveat": "Previous assembled hair may overlap this ROI; r6 value is pixel appearance difference, not necessarily pure skin color difference."
    }
  ],
  "limitations": [
    "Original-visible skin mask excludes hair in the forehead ROI. Existing/new hair overlap can affect assembled ROI error.",
    "These patches do not measure face shape, eye detail, hair fidelity or overall character likeness."
  ]
}