FAILURE MAP
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FA-79096 / Image orientation metadata / Open access

Front camera rotation adds the device turn like the back camera · case 01

Landscape selfies are saved upside down.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The mirrored front sensor composes the device rotation in the same direction as the back sensor.

VERIFIED REPAIR

For the mirrored sensor subtract the device rotation from its 270 degree mount.

Unsuccessful approach: Using the back-camera mount angle with the subtraction is off by a half turn.

Case 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].

Why this case matters

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.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    gx, gy, prev_r, camera = x
    if gx * gx + gy * gy < 300 * 300 or abs(gx) == abs(gy):
        r = prev_r
    elif abs(gy) > abs(gx):
        r = 0 if gy > 0 else 180
    else:
        r = 90 if gx > 0 else 270
    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}
    if camera == 'front':
        total = (270 + r) % 360
        return [from_km[(total // 90, 1)], r]
    total = (90 + r) % 360
    return [from_km[(total // 90, 0)], r]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[439, -411, 180, 'front'], [4, 90]], [[298, 553, 180, 'front'], [5, 0]], [[925, 721, 90, 'front'], [4, 90]], [[-382, -382, 180, 'back'], [8, 180]], [[50, -890, 180, 'back'], [8, 180]], [[53, -848, 270, 'back'], [8, 180]], [[247, -67, 270, 'back'], [1, 270]], [[686, -373, 90, 'front'], [4, 90]]], [[[-835, 686, 0, 'front'], [2, 270]], [[648, -194, 90, 'front'], [4, 90]], [[-926, 466, 0, 'back'], [1, 270]], [[110, -610, 0, 'back'], [8, 180]], [[-900, 900, 270, 'back'], [1, 270]], [[-869, 635, 270, 'back'], [1, 270]], [[-239, -597, 180, 'back'], [8, 180]], [[-993, 66, 0, 'front'], [2, 270]]], [[[-994, 954, 180, 'front'], [2, 270]], [[-176, 109, 270, 'front'], [2, 270]], [[-552, 552, 270, 'front'], [2, 270]], [[486, 992, 270, 'back'], [6, 0]], [[54, 63, 0, 'back'], [6, 0]], [[-86, -105, 270, 'back'], [1, 270]], [[-134, -182, 180, 'back'], [8, 180]], [[717, 36, 90, 'front'], [4, 90]]], [[[-522, 369, 0, 'front'], [2, 270]], [[213, 206, 270, 'front'], [2, 270]], [[-996, 271, 270, 'front'], [2, 270]], [[137, 86, 180, 'back'], [8, 180]], [[116, 53, 90, 'back'], [3, 90]], [[-183, 181, 180, 'back'], [8, 180]], [[-651, 121, 180, 'back'], [1, 270]], [[-899, 899, 90, 'front'], [4, 90]]], [[[-1000, -619, 90, 'front'], [2, 270]], [[-869, -869, 0, 'front'], [5, 0]], [[634, -189, 90, 'front'], [4, 90]], [[816, 260, 0, 'back'], [3, 90]], [[-188, 149, 180, 'back'], [8, 180]], [[-532, 686, 180, 'back'], [6, 0]], [[-67, 67, 270, 'back'], [1, 270]], [[-52, -248, 270, 'front'], [2, 270]]]]
labels = ["regression: front sensor rotation direction", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: front sensor rotation direction 0[2, 90][4, 90]Failed
repair trap 1[5, 0][5, 0]Passed
combined fault 2[2, 90][4, 90]Failed
control 3[8, 180][8, 180]Passed
control 4[8, 180][8, 180]Passed
boundary 5[8, 180][8, 180]Passed
boundary 6[1, 270][1, 270]Passed
control 7[2, 90][4, 90]Failed

SHA-256 / 92713c64e9382ddbc8001dfa5651d98c84874f5a17f9db8c8ee8ffee10f64bca

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    gx, gy, prev_r, camera = x
    if gx * gx + gy * gy < 300 * 300 or abs(gx) == abs(gy):
        r = prev_r
    elif abs(gy) > abs(gx):
        r = 0 if gy > 0 else 180
    else:
        r = 90 if gx > 0 else 270
    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}
    if camera == 'front':
        total = (90 - r) % 360
        return [from_km[(total // 90, 1)], r]
    total = (90 + r) % 360
    return [from_km[(total // 90, 0)], r]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[439, -411, 180, 'front'], [4, 90]], [[298, 553, 180, 'front'], [5, 0]], [[925, 721, 90, 'front'], [4, 90]], [[-382, -382, 180, 'back'], [8, 180]], [[50, -890, 180, 'back'], [8, 180]], [[53, -848, 270, 'back'], [8, 180]], [[247, -67, 270, 'back'], [1, 270]], [[686, -373, 90, 'front'], [4, 90]]], [[[-835, 686, 0, 'front'], [2, 270]], [[648, -194, 90, 'front'], [4, 90]], [[-926, 466, 0, 'back'], [1, 270]], [[110, -610, 0, 'back'], [8, 180]], [[-900, 900, 270, 'back'], [1, 270]], [[-869, 635, 270, 'back'], [1, 270]], [[-239, -597, 180, 'back'], [8, 180]], [[-993, 66, 0, 'front'], [2, 270]]], [[[-994, 954, 180, 'front'], [2, 270]], [[-176, 109, 270, 'front'], [2, 270]], [[-552, 552, 270, 'front'], [2, 270]], [[486, 992, 270, 'back'], [6, 0]], [[54, 63, 0, 'back'], [6, 0]], [[-86, -105, 270, 'back'], [1, 270]], [[-134, -182, 180, 'back'], [8, 180]], [[717, 36, 90, 'front'], [4, 90]]], [[[-522, 369, 0, 'front'], [2, 270]], [[213, 206, 270, 'front'], [2, 270]], [[-996, 271, 270, 'front'], [2, 270]], [[137, 86, 180, 'back'], [8, 180]], [[116, 53, 90, 'back'], [3, 90]], [[-183, 181, 180, 'back'], [8, 180]], [[-651, 121, 180, 'back'], [1, 270]], [[-899, 899, 90, 'front'], [4, 90]]], [[[-1000, -619, 90, 'front'], [2, 270]], [[-869, -869, 0, 'front'], [5, 0]], [[634, -189, 90, 'front'], [4, 90]], [[816, 260, 0, 'back'], [3, 90]], [[-188, 149, 180, 'back'], [8, 180]], [[-532, 686, 180, 'back'], [6, 0]], [[-67, 67, 270, 'back'], [1, 270]], [[-52, -248, 270, 'front'], [2, 270]]]]
labels = ["regression: front sensor rotation direction", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: front sensor rotation direction 0[2, 90][4, 90]Failed
repair trap 1[7, 0][5, 0]Failed
combined fault 2[2, 90][4, 90]Failed
control 3[8, 180][8, 180]Passed
control 4[8, 180][8, 180]Passed
boundary 5[8, 180][8, 180]Passed
boundary 6[1, 270][1, 270]Passed
control 7[2, 90][4, 90]Failed

SHA-256 / 4fcf2ffc49cf67304761bbeeea5e1e52a26020b59b0dd59b9b6a49e1f5849643

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    gx, gy, prev_r, camera = x
    if gx * gx + gy * gy < 300 * 300 or abs(gx) == abs(gy):
        r = prev_r
    elif abs(gy) > abs(gx):
        r = 0 if gy > 0 else 180
    else:
        r = 90 if gx > 0 else 270
    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}
    if camera == 'front':
        total = (270 - r) % 360
        return [from_km[(total // 90, 1)], r]
    total = (90 + r) % 360
    return [from_km[(total // 90, 0)], r]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[[[439, -411, 180, 'front'], [4, 90]], [[298, 553, 180, 'front'], [5, 0]], [[925, 721, 90, 'front'], [4, 90]], [[-382, -382, 180, 'back'], [8, 180]], [[50, -890, 180, 'back'], [8, 180]], [[53, -848, 270, 'back'], [8, 180]], [[247, -67, 270, 'back'], [1, 270]], [[686, -373, 90, 'front'], [4, 90]]], [[[-835, 686, 0, 'front'], [2, 270]], [[648, -194, 90, 'front'], [4, 90]], [[-926, 466, 0, 'back'], [1, 270]], [[110, -610, 0, 'back'], [8, 180]], [[-900, 900, 270, 'back'], [1, 270]], [[-869, 635, 270, 'back'], [1, 270]], [[-239, -597, 180, 'back'], [8, 180]], [[-993, 66, 0, 'front'], [2, 270]]], [[[-994, 954, 180, 'front'], [2, 270]], [[-176, 109, 270, 'front'], [2, 270]], [[-552, 552, 270, 'front'], [2, 270]], [[486, 992, 270, 'back'], [6, 0]], [[54, 63, 0, 'back'], [6, 0]], [[-86, -105, 270, 'back'], [1, 270]], [[-134, -182, 180, 'back'], [8, 180]], [[717, 36, 90, 'front'], [4, 90]]], [[[-522, 369, 0, 'front'], [2, 270]], [[213, 206, 270, 'front'], [2, 270]], [[-996, 271, 270, 'front'], [2, 270]], [[137, 86, 180, 'back'], [8, 180]], [[116, 53, 90, 'back'], [3, 90]], [[-183, 181, 180, 'back'], [8, 180]], [[-651, 121, 180, 'back'], [1, 270]], [[-899, 899, 90, 'front'], [4, 90]]], [[[-1000, -619, 90, 'front'], [2, 270]], [[-869, -869, 0, 'front'], [5, 0]], [[634, -189, 90, 'front'], [4, 90]], [[816, 260, 0, 'back'], [3, 90]], [[-188, 149, 180, 'back'], [8, 180]], [[-532, 686, 180, 'back'], [6, 0]], [[-67, 67, 270, 'back'], [1, 270]], [[-52, -248, 270, 'front'], [2, 270]]]]
labels = ["regression: front sensor rotation direction", "repair trap", "combined fault", "control", "control", "boundary", "boundary", "control"]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (labels[i % len(labels)], i), solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: front sensor rotation direction 0[4, 90][4, 90]Passed
repair trap 1[5, 0][5, 0]Passed
combined fault 2[4, 90][4, 90]Passed
control 3[8, 180][8, 180]Passed
control 4[8, 180][8, 180]Passed
boundary 5[8, 180][8, 180]Passed
boundary 6[1, 270][1, 270]Passed
control 7[4, 90][4, 90]Passed

SHA-256 / c73e206cdf9f232f74b4cb3c0da1f405eac814e40902415076b385c8771ea430

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:49:41.204104+00:00.

Case digest / 6654bbb3df1fa78cd291b056e58df0c619348d31b1ab7111360b20b3b4610ae1