opticflow_calculator.h File Reference

Calculate velocity from optic flow. More...

#include "std.h"
#include "inter_thread_data.h"
#include "lib/vision/image.h"
#include "lib/v4l/v4l2.h"

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Data Structures
struct	opticflow_t

Functions
void	opticflow_calc_init (struct opticflow_t *opticflow, uint16_t w, uint16_t h)
	Initialize the opticflow calculator. More...
void	opticflow_calc_frame (struct opticflow_t *opticflow, struct opticflow_state_t *state, struct image_t *img, struct opticflow_result_t *result)
	Run the optical flow on a new image frame. More...
void	calc_fast9_lukas_kanade (struct opticflow_t *opticflow, struct opticflow_state_t *state, struct image_t *img, struct opticflow_result_t *result)
	Run the optical flow with fast9 and lukaskanade on a new image frame. More...
void	calc_edgeflow_tot (struct opticflow_t *opticflow, struct opticflow_state_t *state, struct image_t *img, struct opticflow_result_t *result)
	Run the optical flow with EDGEFLOW on a new image frame. More...

Detailed Description

Calculate velocity from optic flow.

Using images from a vertical camera and IMU sensor data.

Definition in file opticflow_calculator.h.

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Data Structure Documentation

struct opticflow_t

Definition at line 40 of file opticflow_calculator.h.

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Data Fields
bool	derotation	Derotation switched on or off (depended on the quality of the gyroscope measurement)
bool	fast9_adaptive	Whether the FAST9 threshold should be adaptive.
uint16_t	fast9_min_distance	Minimum distance in pixels between corners.
uint16_t	fast9_padding	Padding used in FAST9 detector.
struct point_t *	fast9_ret_corners	Corners.
uint16_t	fast9_rsize	Amount of corners allocated.
uint8_t	fast9_threshold	FAST9 corner detection threshold.
bool	got_first_img	If we got a image to work with.
struct image_t	img_gray	Current gray image frame.
bool	just_switched_method
uint8_t	max_iterations	The maximum amount of iterations the Lucas Kanade algorithm should do.
uint8_t	max_track_corners	Maximum amount of corners Lucas Kanade should track.
bool	median_filter	Decides to use a median filter on the velocity.
uint8_t	method	Method to use to calculate the optical flow.
struct image_t	prev_img_gray	Previous gray image frame.
struct FloatRates	prev_rates	Gyro Rates from the previous image frame.
struct timeval	prev_timestamp	Timestamp of the previous frame, used for FPS calculation.
uint8_t	pyramid_level	Number of pyramid levels used in Lucas Kanade algorithm (0 == no pyramids used)
uint16_t	search_distance	Search distance for blockmatching alg.
uint16_t	subpixel_factor	The amount of subpixels per pixel.
uint8_t	threshold_vec	The threshold in x, y subpixels which the algorithm should stop.
uint16_t	window_size	Window size for the blockmatching algorithm (general value for all methods)

Function Documentation

void calc_edgeflow_tot	(	struct opticflow_t *	opticflow,
		struct opticflow_state_t *	state,
		struct image_t *	img,
		struct opticflow_result_t *	result
	)

Run the optical flow with EDGEFLOW on a new image frame.

Parameters

[in]	*opticflow	The opticalflow structure that keeps track of previous images
[in]	*state	The state of the drone
[in]	*img	The image frame to calculate the optical flow from
[out]	*result	The optical flow result

Definition at line 404 of file opticflow_calculator.c.

References opticflow_state_t::agl, calc_previous_frame_nr(), calculate_edge_displacement(), calculate_edge_histogram(), opticflow_result_t::corner_cnt, opticflow_t::derotation, DISP_RANGE_MAX, opticflow_result_t::div_size, edge_flow_t::div_x, edge_flow_t::div_y, opticflow_result_t::divergence, draw_edgeflow_img(), FLOAT_RATES_ZERO, opticflow_result_t::flow_der_x, opticflow_result_t::flow_der_y, opticflow_result_t::flow_x, edge_flow_t::flow_x, opticflow_result_t::flow_y, edge_flow_t::flow_y, opticflow_result_t::fps, edge_hist_t::frame_time, getAmountPeaks(), image_t::h, opticflow_t::just_switched_method, line_fit(), MAX_HORIZON, MAX_WINDOW_SIZE, opticflow_t::median_filter, opticflow_result_t::noise_measurement, OPTICFLOW_FOV_H, OPTICFLOW_FOV_W, FloatRates::p, FloatRates::q, opticflow_state_t::rates, edge_hist_t::rates, RES, opticflow_t::search_distance, opticflow_t::subpixel_factor, opticflow_result_t::surface_roughness, timeval_diff(), opticflow_result_t::tracked_cnt, image_t::ts, update_median_filter(), opticflow_result_t::vel_x, opticflow_result_t::vel_y, vel_y_filt, image_t::w, opticflow_t::window_size, edge_hist_t::x, edgeflow_displacement_t::x, edge_hist_t::y, and edgeflow_displacement_t::y.

Referenced by opticflow_calc_frame().

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void calc_fast9_lukas_kanade	(	struct opticflow_t *	opticflow,
		struct opticflow_state_t *	state,
		struct image_t *	img,
		struct opticflow_result_t *	result
	)

Run the optical flow with fast9 and lukaskanade on a new image frame.

Parameters

[in]	*opticflow	The opticalflow structure that keeps track of previous images
[in]	*state	The state of the drone
[in]	*img	The image frame to calculate the optical flow from
[out]	*result	The optical flow result

Definition at line 218 of file opticflow_calculator.c.

References opticflow_state_t::agl, analyze_linear_flow_field(), cmp_flow(), opticflow_result_t::corner_cnt, opticflow_t::derotation, opticflow_result_t::div_size, linear_flow_fit_info::divergence, opticflow_result_t::divergence, opticflow_t::fast9_adaptive, fast9_detect(), FAST9_HIGH_THRESHOLD, FAST9_LOW_THRESHOLD, opticflow_t::fast9_min_distance, opticflow_t::fast9_padding, opticflow_t::fast9_ret_corners, opticflow_t::fast9_rsize, opticflow_t::fast9_threshold, opticflow_result_t::flow_der_x, opticflow_result_t::flow_der_y, opticflow_result_t::flow_x, flow_t::flow_x, opticflow_result_t::flow_y, flow_t::flow_y, opticflow_result_t::fps, get_size_divergence(), opticflow_t::got_first_img, image_t::h, image_copy(), image_show_flow(), image_show_points(), image_switch(), image_to_grayscale(), opticflow_t::img_gray, opticflow_t::just_switched_method, LINEAR_FIT, opticflow_t::max_iterations, opticflow_t::max_track_corners, opticflow_t::median_filter, opticflow_result_t::noise_measurement, opticflow_calc_init(), OPTICFLOW_FOV_H, OPTICFLOW_FOV_W, OPTICFLOW_FX, OPTICFLOW_FY, OPTICFLOW_MAX_TRACK_CORNERS, opticFlowLK(), FloatRates::p, opticflow_t::prev_img_gray, opticflow_t::prev_rates, opticflow_t::prev_timestamp, opticflow_t::pyramid_level, FloatRates::q, opticflow_state_t::rates, SIZE_DIV, opticflow_t::subpixel_factor, linear_flow_fit_info::surface_roughness, opticflow_result_t::surface_roughness, opticflow_t::threshold_vec, timeval_diff(), opticflow_result_t::tracked_cnt, image_t::ts, update_median_filter(), opticflow_result_t::vel_x, opticflow_result_t::vel_y, vel_y_filt, image_t::w, and opticflow_t::window_size.

Referenced by opticflow_calc_frame().

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void opticflow_calc_frame	(	struct opticflow_t *	opticflow,
		struct opticflow_state_t *	state,
		struct image_t *	img,
		struct opticflow_result_t *	result
	)

Run the optical flow on a new image frame.

Parameters

[in]	*opticflow	The opticalflow structure that keeps track of previous images
[in]	*state	The state of the drone
[in]	*img	The image frame to calculate the optical flow from
[out]	*result	The optical flow result

Definition at line 567 of file opticflow_calculator.c.

References calc_edgeflow_tot(), calc_fast9_lukas_kanade(), opticflow_t::just_switched_method, and opticflow_t::method.

Referenced by opticflow_module_calc().

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void opticflow_calc_init	(	struct opticflow_t *	opticflow,
		uint16_t	w,
		uint16_t	h
	)

Initialize the opticflow calculator.

Parameters

[out]	*opticflow	The new optical flow calculator
[in]	*w	The image width
[in]	*h	The image height

Definition at line 175 of file opticflow_calculator.c.

References opticflow_t::derotation, opticflow_t::fast9_adaptive, opticflow_t::fast9_min_distance, opticflow_t::fast9_padding, opticflow_t::fast9_ret_corners, opticflow_t::fast9_rsize, opticflow_t::fast9_threshold, FLOAT_RATES_ZERO, opticflow_t::got_first_img, image_create(), IMAGE_GRAYSCALE, opticflow_t::img_gray, init_median_filter(), opticflow_t::max_iterations, opticflow_t::max_track_corners, opticflow_t::median_filter, opticflow_t::method, OPTICFLOW_DEROTATION, OPTICFLOW_FAST9_ADAPTIVE, OPTICFLOW_FAST9_MIN_DISTANCE, OPTICFLOW_FAST9_PADDING, OPTICFLOW_FAST9_THRESHOLD, OPTICFLOW_MAX_ITERATIONS, OPTICFLOW_MAX_TRACK_CORNERS, OPTICFLOW_MEDIAN_FILTER, OPTICFLOW_METHOD, OPTICFLOW_PYRAMID_LEVEL, OPTICFLOW_SEARCH_DISTANCE, OPTICFLOW_SUBPIXEL_FACTOR, OPTICFLOW_THRESHOLD_VEC, OPTICFLOW_WINDOW_SIZE, opticflow_t::prev_img_gray, opticflow_t::prev_rates, opticflow_t::pyramid_level, opticflow_t::search_distance, opticflow_t::subpixel_factor, opticflow_t::threshold_vec, vel_y_filt, and opticflow_t::window_size.

Referenced by calc_fast9_lukas_kanade().

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