{"abstract":"Photos taken with the phone lying almost flat get a random orientation from sensor noise.","category":"Image orientation metadata","checks":8,"contract":"Input [gx, gy, previous_rotation, camera] with gravity in milli-g in the portrait device frame (x right, y down). Device rotation: keep the previous bucket when the in-plane magnitude is below 300 mg or |gx| == |gy| (hysteresis); otherwise gy dominates -> 0 (gy > 0) or 180, gx dominates -> 90 (gx > 0) or 270. The back sensor is mounted at 90 degrees and needs (90 + r) mod 360 clockwise; the mirrored front sensor is mounted at 270 and needs (270 - r) mod 360 with the mirror bit. The tag comes from (quarter turns, mirror) via 1:(0,0) 2:(0,1) 3:(2,0) 4:(2,1) 5:(3,1) 6:(1,0) 7:(1,1) 8:(3,0). Return [tag, r].","contract_signature":"x","evaluation_group":"w2-image-orientation-metadata-capture-accelerometer","failed_approach":"An L1 norm threshold keeps diagonal readings that exceed 300 mg in Euclidean length only.","family":"w2-image-orientation-metadata-capture-accelerometer-flat-threshold","id":"FA-79081","implementations":{"attempt":{"sha256":"cff9f395f3bb8e921d253b890c946b5b8c1e088aa749845206db21bc1d5835a7","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    gx, gy, prev_r, camera = x\n    if abs(gx) + abs(gy) < 300 or abs(gx) == abs(gy):\n        r = prev_r\n    elif abs(gy) > abs(gx):\n        r = 0 if gy > 0 else 180\n    else:\n        r = 90 if gx > 0 else 270\n    from_km = {(0, 0): 1, (0, 1): 2, (2, 0): 3, (2, 1): 4, (3, 1): 5, (1, 0): 6, (1, 1): 7, (3, 0): 8}\n    if camera == 'front':\n        total = (270 - r) % 360\n        return [from_km[(total // 90, 1)], r]\n    total = (90 + r) % 360\n    return [from_km[(total // 90, 0)], r]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[[[247, -67, 270, 'back'], [1, 270]], [[-206, 207, 90, 'front'], [4, 90]], [[-382, -382, 180, 'back'], [8, 180]], [[50, -890, 180, 'back'], [8, 180]], [[298, 553, 180, 'front'], [5, 0]], [[53, -848, 270, 'back'], [8, 180]], [[743, -746, 270, 'back'], [8, 180]], [[201, -186, 180, 'back'], [8, 180]]], [[[-64, 236, 90, 'back'], [3, 90]], [[-230, 73, 180, 'back'], [8, 180]], [[-177, 195, 270, 'back'], [1, 270]], [[-926, 466, 0, 'back'], [1, 270]], [[110, -610, 0, 'back'], [8, 180]], [[-900, 900, 270, 'back'], [1, 270]], [[-869, 635, 270, 'back'], [1, 270]], [[-232, -166, 90, 'front'], [4, 90]]], [[[232, -182, 180, 'back'], [8, 180]], [[-237, -89, 90, 'back'], [3, 90]], [[153, 257, 270, 'front'], [2, 270]], [[741, -322, 270, 'back'], [3, 90]], [[486, 992, 270, 'back'], [6, 0]], [[54, 63, 0, 'back'], [6, 0]], [[-134, -182, 180, 'back'], [8, 180]], [[-73, 247, 90, 'back'], [3, 90]]], [[[137, 86, 180, 'back'], [8, 180]], [[-213, -186, 90, 'back'], [3, 90]], [[-186, 190, 270, 'back'], [1, 270]], [[230, 230, 270, 'back'], [1, 270]], [[66, -283, 180, 'front'], [7, 180]], [[116, 53, 90, 'back'], [3, 90]], [[-651, 121, 180, 'back'], [1, 270]], [[175, -26, 270, 'back'], [1, 270]]], [[[6, -76, 270, 'front'], [2, 270]], [[54, 289, 270, 'back'], [1, 270]], [[-107, 977, 90, 'back'], [6, 0]], [[816, 260, 0, 'back'], [3, 90]], [[994, 659, 180, 'front'], [4, 90]], [[-532, 686, 180, 'back'], [6, 0]], [[-22, 28, 0, 'front'], [5, 0]], [[-52, -248, 270, 'front'], [2, 270]]]]\nlabels = [\"regression: flat-device magnitude threshold\", \"repair trap\", \"combined fault\", \"control\", \"control\", \"boundary\", \"boundary\", \"control\"]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (labels[i % len(labels)], i), solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"9753b5b7fcbac82f95806e409dd6a86ab5b7d590cdf2bda613ca5aac66df72bf","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    gx, gy, prev_r, camera = x\n    if gx * gx + gy * gy < 300 or abs(gx) == abs(gy):\n        r = prev_r\n    elif abs(gy) > abs(gx):\n        r = 0 if gy > 0 else 180\n    else:\n        r = 90 if gx > 0 else 270\n    from_km = {(0, 0): 1, (0, 1): 2, (2, 0): 3, (2, 1): 4, (3, 1): 5, (1, 0): 6, (1, 1): 7, (3, 0): 8}\n    if camera == 'front':\n        total = (270 - r) % 360\n        return [from_km[(total // 90, 1)], r]\n    total = (90 + r) % 360\n    return [from_km[(total // 90, 0)], r]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[[[247, -67, 270, 'back'], [1, 270]], [[-206, 207, 90, 'front'], [4, 90]], [[-382, -382, 180, 'back'], [8, 180]], [[50, -890, 180, 'back'], [8, 180]], [[298, 553, 180, 'front'], [5, 0]], [[53, -848, 270, 'back'], [8, 180]], [[743, -746, 270, 'back'], [8, 180]], [[201, -186, 180, 'back'], [8, 180]]], [[[-64, 236, 90, 'back'], [3, 90]], [[-230, 73, 180, 'back'], [8, 180]], [[-177, 195, 270, 'back'], [1, 270]], [[-926, 466, 0, 'back'], [1, 270]], [[110, -610, 0, 'back'], [8, 180]], [[-900, 900, 270, 'back'], [1, 270]], [[-869, 635, 270, 'back'], [1, 270]], [[-232, -166, 90, 'front'], [4, 90]]], [[[232, -182, 180, 'back'], [8, 180]], [[-237, -89, 90, 'back'], [3, 90]], [[153, 257, 270, 'front'], [2, 270]], [[741, -322, 270, 'back'], [3, 90]], [[486, 992, 270, 'back'], [6, 0]], [[54, 63, 0, 'back'], [6, 0]], [[-134, -182, 180, 'back'], [8, 180]], [[-73, 247, 90, 'back'], [3, 90]]], [[[137, 86, 180, 'back'], [8, 180]], [[-213, -186, 90, 'back'], [3, 90]], [[-186, 190, 270, 'back'], [1, 270]], [[230, 230, 270, 'back'], [1, 270]], [[66, -283, 180, 'front'], [7, 180]], [[116, 53, 90, 'back'], [3, 90]], [[-651, 121, 180, 'back'], [1, 270]], [[175, -26, 270, 'back'], [1, 270]]], [[[6, -76, 270, 'front'], [2, 270]], [[54, 289, 270, 'back'], [1, 270]], [[-107, 977, 90, 'back'], [6, 0]], [[816, 260, 0, 'back'], [3, 90]], [[994, 659, 180, 'front'], [4, 90]], [[-532, 686, 180, 'back'], [6, 0]], [[-22, 28, 0, 'front'], [5, 0]], [[-52, -248, 270, 'front'], [2, 270]]]]\nlabels = [\"regression: flat-device magnitude threshold\", \"repair trap\", \"combined fault\", \"control\", \"control\", \"boundary\", \"boundary\", \"control\"]\nfor i, (args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (labels[i % len(labels)], i), solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic bounded teaching model with a stipulated contract; it makes no claim of conformance to any published specification. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-image-orientation-metadata-capture-accelerometer-flat-threshold","generated_at":"2026-09-29T14:49:41.160684+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Camera, phone and scanner images carry an orientation hint separately from the stored pixels; galleries, thumbnailers, editors and upload pipelines must interpret it consistently or photos appear sideways, mirrored or doubly rotated.","root_cause":"The squared in-plane magnitude is compared with 300 rather than 300 squared, so the hold never triggers.","sha256":"6ab43105fbfcdd39201e0addbf0899ca115b92b76d051145a01f303621467b32","title":"Flat-device detection compares squared magnitude to an unsquared threshold · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":41.895,"exit_code":1,"observations":[{"actual":[3,90],"check":"regression: flat-device magnitude threshold 0","expected":[1,270],"passed":false},{"actual":[5,0],"check":"repair trap 1","expected":[4,90],"passed":false},{"actual":[8,180],"check":"combined fault 2","expected":[8,180],"passed":true},{"actual":[8,180],"check":"control 3","expected":[8,180],"passed":true},{"actual":[5,0],"check":"control 4","expected":[5,0],"passed":true},{"actual":[8,180],"check":"boundary 5","expected":[8,180],"passed":true},{"actual":[8,180],"check":"boundary 6","expected":[8,180],"passed":true},{"actual":[3,90],"check":"control 7","expected":[8,180],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: flat-device magnitude threshold 0\", \"actual\": [3, 90], \"expected\": [1, 270], \"passed\": false}, {\"check\": \"repair trap 1\", \"actual\": [5, 0], \"expected\": [4, 90], \"passed\": false}, {\"check\": \"combined fault 2\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 3\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 4\", \"actual\": [5, 0], \"expected\": [5, 0], \"passed\": true}, {\"check\": \"boundary 5\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"boundary 6\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 7\", \"actual\": [3, 90], \"expected\": [8, 180], \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.777,"exit_code":1,"observations":[{"actual":[3,90],"check":"regression: flat-device magnitude threshold 0","expected":[1,270],"passed":false},{"actual":[5,0],"check":"repair trap 1","expected":[4,90],"passed":false},{"actual":[8,180],"check":"combined fault 2","expected":[8,180],"passed":true},{"actual":[8,180],"check":"control 3","expected":[8,180],"passed":true},{"actual":[5,0],"check":"control 4","expected":[5,0],"passed":true},{"actual":[8,180],"check":"boundary 5","expected":[8,180],"passed":true},{"actual":[8,180],"check":"boundary 6","expected":[8,180],"passed":true},{"actual":[3,90],"check":"control 7","expected":[8,180],"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression: flat-device magnitude threshold 0\", \"actual\": [3, 90], \"expected\": [1, 270], \"passed\": false}, {\"check\": \"repair trap 1\", \"actual\": [5, 0], \"expected\": [4, 90], \"passed\": false}, {\"check\": \"combined fault 2\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 3\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 4\", \"actual\": [5, 0], \"expected\": [5, 0], \"passed\": true}, {\"check\": \"boundary 5\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"boundary 6\", \"actual\": [8, 180], \"expected\": [8, 180], \"passed\": true}, {\"check\": \"control 7\", \"actual\": [3, 90], \"expected\": [8, 180], \"passed\": false}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}