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nx_undertone_class.nx

buildroot/runtime/nx_undertone_class.nx

9719 B274 linesdepth 3pulls 3 transitivereach 7 importersview sourcekind tool
docsdependenciesstructsconstsfunctions

about

nx_undertone_class.nx -- Tier 4 skin-undertone classification. Tier 4 of nxc2/docs/IMAGE_VALIDATION_AMBIGUITY_LADDER.md. Where ITA (nx_skin_tone_ita) classifies the LIGHT-TO-DARK axis (luminance + b*), undertone classifies the CHROMA TYPE axis (cool / warm / neutral) -- the dimension that makes the SAME ITA band look "golden" vs "pink". Standard cosmetic-industry definition (Suzuki 1987, Fitzpatrick 1988 supplement, Robinson-Bostom & DiGiovanna 2010): h_ab = atan2(b*, a*) -- CIELab hue angle in degrees For typical skin h_ab falls in [30, 80] degrees. Within that range: h_ab > 55 -> WARM (golden / yellow leaning) 45..55 -> NEUTRAL (balanced) h_ab < 45 -> COOL (pink / red leaning) Outside [20, 90]: classifier returns INVALID_RANGE -- the pixel sample isn't typical-skin chroma; caller likely fed a non-skin region. Confidence proxy in Q10: distance from nearest threshold. Larger distance from the WARM/COOL boundary = higher confidence in the classification. genealogy_id: suzuki_1987_robinson_2010 lineage_id: substrate_skin_chroma_v1

dependencies 3 imports · 3 importers

nx_syscalls.nx nx_runtime.nx nx_tier.nx nx_undertone_class.nx nx_image_grade_v0.nx nx_image_grade_v1.nx nx_image_grade_v2.nx

imports: nx_syscalls.nxnx_runtime.nxnx_tier.nx

imported by: nx_image_grade_v0.nxnx_image_grade_v1.nxnx_image_grade_v2.nx

call flow from main pre-order; caps 40 nodes / depth 6 declared; ↻ = already shown

main nx_undertone_classify sys_mmap _ut_atan2_q10 _ut_cordic_angle_q10 _ut_distance_from_boundary

structs

70struct NxUndertoneResult

consts

40const NX_MAGIC_46080: i64 = 46080
41const NX_MAGIC_27203: i64 = 27203
42const NX_MAGIC_14373: i64 = 14373
43const NX_MAGIC_7296: i64 = 7296
44const NX_MAGIC_3662: i64 = 3662
45const NX_MAGIC_1833: i64 = 1833
46const NX_MAGIC_1024: i64 = 1024
48const NX_UT_Q10: nx_int = 1024
51const NX_UT_INVALID: nx_int = 0
52const NX_UT_COOL: nx_int = 1
53const NX_UT_NEUTRAL: nx_int = 2
54const NX_UT_WARM: nx_int = 3
55const NX_UT_N_CLASSES: nx_int = 4
58const NX_UT_THR_WARM_Q10: nx_int = 56320 // 55 deg
59const NX_UT_THR_NEUTRAL_LO: nx_int = 46080 // 45 deg
60const NX_UT_THR_VALID_LO: nx_int = 20480 // 20 deg
61const NX_UT_THR_VALID_HI: nx_int = 92160 // 90 deg
66const NX_UT_CONF_DEG_MAX: nx_int = 35
79const NX_UT_RESULT_BYTES: nx_size = 48
88const NX_UT_CORDIC_ITERS: nx_int = 8

functions

90func _ut_cordic_angle_q10(i: nx_int) -> nx_int
called by 1: _ut_atan2_q10
102func _ut_atan2_q10(y_q10: nx_int, x_q10: nx_int) -> nx_int
called by 1: nx_undertone_classify calls 1: _ut_cordic_angle_q10
153func _ut_distance_from_boundary_q10(h_q10: nx_int, verdict: nx_int) -> nx_int
called by 1: nx_undertone_classify
173func nx_undertone_classify(a_q10: nx_int, b_q10: nx_int) -> *NxUndertoneResult
called by 4: _igv0_lab_undertonenx_image_grade_v1nx_image_grade_v2main calls 3: sys_mmap_ut_atan2_q10_ut_distance_from_boundary_q10
220func main() -> nx_int
calls 1: nx_undertone_classify