track_keypoints() [1/2]

MAYAFLUX_API std::vector< TrackResult > MayaFlux::Kinesis::Vision::track_keypoints	(	std::span< const float >	prev_gray,
		std::span< const float >	curr_gray,
		std::span< const float >	grad_dx,
		std::span< const float >	grad_dy,
		uint32_t	w,
		uint32_t	h,
		std::span< const glm::vec2 >	prev_points,
		uint32_t	window_radius = 7,
		uint32_t	max_iterations = 20,
		float	eigen_threshold = 1e-4F,
		float	error_threshold = 0.3F
	)

Track keypoints using a pre-computed Sobel gradient of prev_gray.

Identical to the four-parameter overload but accepts caller-supplied dx and dy of the previous frame, avoiding recomputation when the gradient is already cached. dx and dy must be the Sobel gradient of prev_gray at the same w x h resolution.

Parameters

prev_gray	Previous frame, single-channel float, size w * h.
curr_gray	Current frame, single-channel float, size w * h.
grad_dx	Horizontal Sobel gradient of prev_gray, size w * h.
grad_dy	Vertical Sobel gradient of prev_gray, size w * h.
w	Image width in pixels.
h	Image height in pixels.
prev_points	Points to track in normalised [0, 1] coordinates.
window_radius	Half-size of the tracking patch in pixels.
max_iterations	Maximum Newton-Raphson iterations per point.
eigen_threshold	Minimum eigenvalue for structure tensor validity.
error_threshold	Maximum residual error to accept a track.

Returns

TrackResult per input point, same order.

Definition at line 189 of file OpticalFlow.cpp.

{
    const size_t np = prev_points.size();
    std::vector<TrackResult> results(np);
 
    P::for_each(P::par_unseq,
        std::views::iota(size_t { 0 }, np).begin(),
        std::views::iota(size_t { 0 }, np).end(),
        [&](size_t i) {
            results[i] = lk_point(
                prev_gray, curr_gray,
                grad_dx, grad_dy,
                w, h,
                prev_points[i],
                window_radius,
                max_iterations,
                eigen_threshold,
                error_threshold);
        });
 
    return results;
}

References h.