nx_motion.nx

buildroot/runtime/nx_motion.nx

18817 B459 linesdepth 5pulls 6 transitivereach 3 importersview sourcekind librarytopic motion

docs dependencies structs consts functions

about

nx_motion.nx -- frame-to-frame motion (Lucas-Kanade optical flow). Brightness-constancy + small-motion assumption: I(x, y, t) = I(x + u, y + v, t + 1) Taylor expand: I_x * u + I_y * v + I_t = 0 Over an N-pixel window this is N equations in 2 unknowns; solve via 2x2 least-squares (normal equations + Cramer's rule). What this unlocks: + motion detection (frame diff) + tracking (per-pixel flow vectors) + camera-motion estimation (mean flow direction) + scene-cut detection (flow magnitude spike) + activity recognition substrate Returns flow in Q8 sub-pixel precision (1 unit = 1/256 pixel). 5x5 integration window default. genealogy_id: lucas_kanade_1981 + horn_schunck_1981 lineage_id: gradient_based_optical_flow + 2x2_least_squares

dependencies 2 imports · 3 importers

imports: syscalls.nxnx_image.nx

imported by: nx_dynaoracle.nxnx_dynaoracle_gate.nxnx_motion_test.nx

structs

97	struct FlowField
323	struct MotionPyr

consts

32	const NX_MOTION_Q: i64 = 256 // Q8 sub-pixel
33	const NX_MOTION_WIN: i64 = 5 // 5x5 integration
40	const NX_MOTION_LK_DOMAIN_Q8: i64 = (NX_MOTION_WIN / 2) * NX_MOTION_Q
321	const NX_MOTION_PYR_MAX: i64 = 6
334	const NX_MOTION_PYR_BYTES: i64 = 72

functions

46	func nx_motion_frame_diff(a: Image, b: Image) -> *Image called by 1: main calls 3: nx_image_alloc nx_image_get nx_image_set
71	func nx_motion_temporal_grad_into(frame1: Image, frame2: Image, dst: ImageS64) -> ImageS64 called by 2: nx_motion_lucas_kanade_into nx_motion_temporal_grad calls 2: nx_image_get nx_image_s64_set
109	func nx_motion_lucas_kanade_into(frame1: Image, frame2: Image, called by 2: nx_motion_lucas_kanade nx_motion_mean_flow_pyr calls 5: nx_image_sobel_x_into nx_image_sobel_y_into nx_motion_temporal_grad_into nx_image_s64_set nx_image_s64_get
212	func nx_motion_mean_flow_rect_bounded(flow: *FlowField, mag_threshold: i64, max_mag_q8: i64, called by 2: nx_motion_mean_flow_rect nx_motion_mean_flow_pyr calls 1: nx_image_s64_get
269	func nx_motion_mean_flow_rect(flow: *FlowField, mag_threshold: i64, called by 1: nx_motion_mean_flow calls 1: nx_motion_mean_flow_rect_bounded
278	func nx_motion_mean_flow(flow: *FlowField, mag_threshold: i64, called by 1: main calls 1: nx_motion_mean_flow_rect
290	func nx_motion_temporal_grad(frame1: Image, frame2: Image) -> *ImageS64 called by 1: main calls 2: nx_image_s64_alloc nx_motion_temporal_grad_into
295	func nx_motion_lucas_kanade(frame1: Image, frame2: Image) -> *FlowField called by 1: main calls 2: nx_image_s64_alloc nx_motion_lucas_kanade_into
339	func nx_motion_pyr_levels(w: i64, h: i64) -> i64 called by 1: nx_motion_pyr_new
355	func nx_motion_pyr_new(w: i64, h: i64) -> *MotionPyr called by 1: main calls 3: nx_motion_pyr_levels nx_image_s64_alloc nx_image_alloc
387	func nx_motion_copy_into(src: Image, dst: Image) -> *Image called by 1: nx_motion_mean_flow_pyr calls 2: nx_image_set nx_image_get
402	func nx_motion_mean_flow_pyr(p: MotionPyr, f1: Image, f2: *Image, mag_threshold: i64, called by 1: main calls 5: nx_motion_copy_into nx_image_downsample2_into nx_image_shift_into nx_motion_lucas_kanade_into nx_motion_mean_flow_rect_bounded