Image helper functions like resizing, color filter, converters... More...

#include "std.h"
#include <sys/time.h>
#include <state.h>

Include dependency graph for image.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	image_t

struct	point_t

struct	point3d_t

struct	flow_t

struct	img_size_t

struct	crop_t

Enumerations
enum	image_type { IMAGE_YUV422 , IMAGE_GRAYSCALE , IMAGE_JPEG , IMAGE_GRADIENT , IMAGE_INT16 }

Functions
void	image_add_border (struct image_t input, struct image_t output, uint8_t border_size)
	This function adds padding to input image by mirroring the edge image elements. More...

void	image_create (struct image_t *img, uint16_t width, uint16_t height, enum image_type type)
	Create a new image. More...

void	image_free (struct image_t *img)
	Free the image. More...

void	image_copy (struct image_t input, struct image_t output)
	Copy an image from inut to output This will only work if the formats are the same. More...

void	image_switch (struct image_t a, struct image_t b)
	This will switch image a and b This is faster as image_copy because it doesn't copy the whole image buffer. More...

void	image_to_grayscale (struct image_t input, struct image_t output)
	Convert an image to grayscale. More...

uint16_t	image_yuv422_colorfilt (struct image_t input, struct image_t output, uint8_t y_m, uint8_t y_M, uint8_t u_m, uint8_t u_M, uint8_t v_m, uint8_t v_M)
	Filter colors in an YUV422 image. More...

int	check_color_yuv422 (struct image_t *im, int x, int y, uint8_t y_m, uint8_t y_M, uint8_t u_m, uint8_t u_M, uint8_t v_m, uint8_t v_M)
	Checks the color of a single pixel in a YUV422 image. More...

void	set_color_yuv422 (struct image_t *im, int x, int y, uint8_t Y, uint8_t U, uint8_t V)
	Sets Y,U,V for a single pixel. More...

void	image_yuv422_downsample (struct image_t input, struct image_t output, uint8_t downsample)
	Simplified high-speed low CPU downsample function without averaging downsample factor must be 1, 2, 4, 8 ... More...

void	image_subpixel_window (struct image_t input, struct image_t output, struct point_t *center, uint32_t subpixel_factor, uint8_t border_size)
	This outputs a subpixel window image in grayscale Currently only works with Grayscale images as input but could be upgraded to also support YUV422 images. More...

void	image_gradients (struct image_t input, struct image_t dx, struct image_t *dy)
	Calculate the gradients using the following matrix: [0 -1 0; -1 0 1; 0 1 0]. More...

void	image_calculate_g (struct image_t dx, struct image_t dy, int32_t *g)
	Calculate the G vector of an image gradient This is used for optical flow calculation. More...

uint32_t	image_difference (struct image_t img_a, struct image_t img_b, struct image_t *diff)
	Calculate the difference between two images and return the error This will only work with grayscale images. More...

int32_t	image_multiply (struct image_t img_a, struct image_t img_b, struct image_t *mult)
	Calculate the multiplication between two images and return the error This will only work with image gradients. More...

void	image_show_points (struct image_t img, struct point_t points, uint16_t points_cnt)
	Show points in an image by coloring them through giving the pixels the maximum value. More...

void	image_show_points_color (struct image_t img, struct point_t points, uint16_t points_cnt, uint8_t *color)
	Show points in an image by coloring them through giving the pixels the maximum value. More...

void	image_show_flow_color (struct image_t img, struct flow_t vectors, uint16_t points_cnt, uint8_t subpixel_factor, const uint8_t color, const uint8_t bad_color)
	Shows the flow from a specific point to a new point This works on YUV422 and Grayscale images. More...

void	image_show_flow (struct image_t img, struct flow_t vectors, uint16_t points_cnt, uint8_t subpixel_factor)

void	image_draw_crosshair (struct image_t img, struct point_t loc, const uint8_t *color, uint32_t size_crosshair)
	Draw a cross-hair on the image. More...

void	image_draw_rectangle (struct image_t img, int x_min, int x_max, int y_min, int y_max, uint8_t color)
	Draw a rectangle on the image. More...

void	image_draw_line (struct image_t img, struct point_t from, struct point_t *to)
	Draw a pink line on the image. More...

void	image_draw_line_color (struct image_t img, struct point_t from, struct point_t to, const uint8_t color)
	Draw a line on the image. More...

void	pyramid_next_level (struct image_t input, struct image_t output, uint8_t border_size)
	This function takes previous padded pyramid level and outputs next level of pyramid without padding. More...

void	pyramid_build (struct image_t input, struct image_t output_array, uint8_t pyr_level, uint16_t border_size)
	This function populates given array of image_t structs with wanted number of padded pyramids based on given input. More...

void	image_gradient_pixel (struct image_t img, struct point_t loc, int method, int dx, int dy)
	Get the gradient at a pixel location. More...

uint8_t	ker_mul_3x3 (uint8_t const source, int_fast8_t const kernel, uint8_t total, uint8_t setting, int width, int YUV)
	Kernel multiplication for a 3 x 3 kernel. More...

void	image_convolution_3x3 (struct image_t input, struct image_t output, int_fast8_t const *kernel, uint8_t kernel_total)
	Image convolution for a 3x3 kernel. More...

Detailed Description

Image helper functions like resizing, color filter, converters...

Definition in file image.h.

Data Structure Documentation

◆ image_t

struct image_t

Definition at line 44 of file image.h.

Collaboration diagram for image_t:

Data Fields
void *	buf	Image buffer (depending on the image_type)
uint8_t	buf_idx	Buffer index for V4L2 freeing.
uint32_t	buf_size	The buffer size.
struct FloatEulers	eulers	Euler Angles at time of image.
uint16_t	h	Image height.
uint32_t	pprz_ts	The timestamp in us since system startup.
struct timeval	ts	The timestamp of creation.
enum image_type	type	The image type.
uint16_t	w	Image width.

◆ point_t

struct point_t

Definition at line 58 of file image.h.

Data Fields
uint16_t	count	Number of times the point has been tracked successfully.
uint32_t	x	The x coordinate of the point.
uint16_t	x_sub	The x subpixel coordinate of the point.
uint32_t	y	The y coordinate of the point.
uint16_t	y_sub	The y subpixel coordinate of the point.

◆ point3d_t

struct point3d_t

Definition at line 68 of file image.h.

Data Fields
float	X	The x coordinate of the point.
float	Y	The y coordinate of the point.
float	Z	The y coordinate of the point.

◆ flow_t

struct flow_t

Definition at line 78 of file image.h.

Collaboration diagram for flow_t:

Data Fields
uint32_t	error	The matching error in the tracking process in subpixels.
int32_t	flow_x	The x direction flow in subpixels.
int32_t	flow_y	The y direction flow in subpixels.
struct point_t	pos	The original position the flow comes from in subpixels.

◆ img_size_t

struct img_size_t

Definition at line 86 of file image.h.

Data Fields
uint16_t	h	The height.
uint16_t	w	The width.

◆ crop_t

struct crop_t

Definition at line 92 of file image.h.

Data Fields
uint16_t	h	height of the cropped area
uint16_t	w	Width of the cropped area.
uint16_t	x	Start position x (horizontal)
uint16_t	y	Start position y (vertical)

Enumeration Type Documentation

◆ image_type

enum image_type

Enumerator
IMAGE_YUV422	UYVY format (uint16 per pixel)
IMAGE_GRAYSCALE	Grayscale image with only the Y part (uint8 per pixel)
IMAGE_JPEG	An JPEG encoded image (not per pixel encoded)
IMAGE_GRADIENT	An image gradient (int16 per pixel)
IMAGE_INT16	An image to hold disparity image data from openCV (int16 per pixel)

Definition at line 35 of file image.h.

Function Documentation

◆ check_color_yuv422()

int check_color_yuv422	(	struct image_t *	im,
		int	x,
		int	y,
		uint8_t	y_m,
		uint8_t	y_M,
		uint8_t	u_m,
		uint8_t	u_M,
		uint8_t	v_m,
		uint8_t	v_M
	)

Checks the color of a single pixel in a YUV422 image.

1 means that it passes the filter, 0 that it does not.

Parameters

[in]	im	The input image to filter
[in]	x	The x-coordinate of the pixel
[in]	y	The y-coordinate of the pixel
[in]	y_m	The Y minimum value
[in]	y_M	The Y maximum value
[in]	u_m	The U minimum value
[in]	u_M	The U maximum value
[in]	v_m	The V minimum value
[in]	v_M	The V maximum value

Returns: The success of the filter.

Definition at line 237 of file image.c.

References image_t::buf, image_t::h, and image_t::w.

Referenced by check_color_snake_gate_detection().

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◆ image_add_border()

void image_add_border	(	struct image_t *	input,
		struct image_t *	output,
		uint8_t	border_size
	)

This function adds padding to input image by mirroring the edge image elements.

Parameters

[in]	*input	- input image (grayscale only)
[out]	*output	- the output image
[in]	border_size	- amount of padding around image. Padding is made by reflecting image elements at the edge Example: f e d c b a \| a b c d e f \| f e d c b a

Definition at line 368 of file image.c.

References image_t::buf, image_t::h, image_create(), image_t::type, and image_t::w.

Referenced by pyramid_build().

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◆ image_calculate_g()

void image_calculate_g	(	struct image_t *	dx,
		struct image_t *	dy,
		int32_t *	g
	)

Calculate the G vector of an image gradient This is used for optical flow calculation.

Parameters

[in]	*dx	The gradient in the X direction
[in]	*dy	The gradient in the Y direction
[out]	*g	The G[4] vector devided by 255 to keep in range

Definition at line 573 of file image.c.

References image_t::buf, g, image_t::h, and image_t::w.

Referenced by opticFlowLK(), and opticFlowLK_flat().

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◆ image_convolution_3x3()

void image_convolution_3x3	(	struct image_t *	input,
		struct image_t *	output,
		int_fast8_t const *	kernel,
		uint8_t	kernel_total
	)

Image convolution for a 3x3 kernel.

Parameters

[in]	input	Input image
[in,out]	output	Output image
[in]	kernel	The kernel values

Definition at line 1068 of file image.c.

References image_t::buf, dest, image_t::eulers, image_t::h, IMAGE_GRAYSCALE, IMAGE_YUV422, ker_mul_3x3(), image_t::pprz_ts, image_t::ts, image_t::type, image_t::w, point_t::x, and point_t::y.

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◆ image_copy()

void image_copy	(	struct image_t *	input,
		struct image_t *	output
	)

Copy an image from inut to output This will only work if the formats are the same.

Parameters

[in]	*input	The input image to copy from
[out]	*output	The out image to copy to

Definition at line 89 of file image.c.

References image_t::buf, image_t::buf_size, image_t::eulers, image_t::h, image_t::pprz_ts, image_t::ts, image_t::type, and image_t::w.

Referenced by calc_fast9_lukas_kanade(), cv_async_function(), and undistort_image_func().

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◆ image_create()

void image_create	(	struct image_t *	img,
		uint16_t	width,
		uint16_t	height,
		enum image_type	type
	)

Create a new image.

Parameters

[out]	*img	The output image
[in]	width	The width of the image
[in]	height	The height of the image
[in]	type	The type of image (YUV422 or grayscale)

Definition at line 43 of file image.c.

References image_t::buf, image_t::buf_size, CACHE_LINE_LENGTH, image_t::h, IMAGE_GRADIENT, IMAGE_INT16, IMAGE_JPEG, IMAGE_YUV422, image_t::type, and image_t::w.

Referenced by calc_fast9_lukas_kanade(), cv_async_function(), cv_blob_locator_func(), cv_window_func(), detect_window(), image_add_border(), log_image(), opticFlowLK(), opticFlowLK_flat(), pano_unwrap_init(), pyramid_next_level(), qrscan(), set_output_image_size(), undistort_image_func(), video_capture_save(), video_thread_function(), and viewvideo_function().

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◆ image_difference()

uint32_t image_difference	(	struct image_t *	img_a,
		struct image_t *	img_b,
		struct image_t *	diff
	)

Calculate the difference between two images and return the error This will only work with grayscale images.

Parameters

[in]	*img_a	The image to substract from
[in]	*img_b	The image to substract from img_a
[out]	*diff	The image difference (if not needed can be NULL)

Returns: The squared difference summed

Definition at line 605 of file image.c.

References image_t::buf, image_t::h, and image_t::w.

Referenced by opticFlowLK(), and opticFlowLK_flat().

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◆ image_draw_crosshair()

void image_draw_crosshair	(	struct image_t *	img,
		struct point_t *	loc,
		const uint8_t *	color,
		uint32_t	size_crosshair
	)

Draw a cross-hair on the image.

Parameters

[in,out]	*img	The image to show the line on
[in]	loc	The location of the cross-hair
[in]	color	The line color as a [U, Y1, V, Y2] uint8_t array, or a uint8_t value pointer for grayscale images. Example colors: white = {127, 255, 127, 255}, green = {0, 127, 0, 127};
[in]	size_crosshair	Actually the half size of the cross hair

Definition at line 891 of file image.c.

References image_t::h, image_draw_line_color(), image_t::w, point_t::x, and point_t::y.

Referenced by draw_gate_color_polygon(), draw_gate_color_square(), image_show_flow_color(), image_show_points_color(), and snake_gate_detection().

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◆ image_draw_line()

void image_draw_line	(	struct image_t *	img,
		struct point_t *	from,
		struct point_t *	to
	)

Draw a pink line on the image.

Parameters

[in,out]	*img	The image to show the line on
[in]	*from	The point to draw from
[in]	*to	The point to draw to

Definition at line 917 of file image.c.

References image_draw_line_color().

Referenced by draw_edgeflow_img(), and qrscan().

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◆ image_draw_line_color()

void image_draw_line_color	(	struct image_t *	img,
		struct point_t *	from,
		struct point_t *	to,
		const uint8_t *	color
	)

Draw a line on the image.

Parameters

[in,out]	*img	The image to show the line on
[in]	*from	The point to draw from
[in]	*to	The point to draw to
[in]	*color	The line color as a [U, Y1, V, Y2] uint8_t array, or a uint8_t value pointer for grayscale images. Example colors: white = {127, 255, 127, 255}, green = {0, 127, 0, 127};

Definition at line 932 of file image.c.

References image_t::buf, image_t::h, IMAGE_YUV422, image_t::type, image_t::w, point_t::x, and point_t::y.

Referenced by draw_gate_color_polygon(), draw_gate_color_square(), image_draw_crosshair(), image_draw_line(), image_draw_rectangle(), and image_show_flow_color().

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◆ image_draw_rectangle()

void image_draw_rectangle	(	struct image_t *	img,
		int	x_min,
		int	x_max,
		int	y_min,
		int	y_max,
		uint8_t *	color
	)

Draw a rectangle on the image.

Parameters

[in,out]	*img	The image to show the line on
[in]	x_min	start in x
[in]	x_max	end of x
[in]	y_min	start in y
[in]	y_max	end of y
[in]	color	in [U, Y, V, Y] format

Definition at line 849 of file image.c.

References image_draw_line_color(), point_t::x, and point_t::y.

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◆ image_free()

void image_free ( struct image_t * img )

Free the image.

Parameters

[in] *img The image to free

Definition at line 75 of file image.c.

References image_t::buf.

Referenced by cv_async_function(), cv_blob_locator_func(), cv_window_func(), detect_window(), opticFlowLK(), opticFlowLK_flat(), pyramid_build(), set_output_image_size(), undistort_image_func(), video_capture_save(), video_thread_function(), and viewvideo_function().

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◆ image_gradient_pixel()

void image_gradient_pixel	(	struct image_t *	img,
		struct point_t *	loc,
		int	method,
		int *	dx,
		int *	dy
	)

Get the gradient at a pixel location.

Parameters

[in,out]	*img	The image
[in]	loc	The location at which to get the gradient
[in]	method	0 = {-1, 0, 1}, 1 = Sobel {-1, 0, 1; -2, 0, 2; -1, 0, 1}
[in]	dx	The gradient in x-direction
[in]	dy	The gradient in y-direction

Definition at line 777 of file image.c.

References image_t::buf, image_t::h, IMAGE_YUV422, image_t::type, image_t::w, point_t::x, and point_t::y.

Referenced by act_fast().

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◆ image_gradients()

void image_gradients	(	struct image_t *	input,
		struct image_t *	dx,
		struct image_t *	dy
	)

Calculate the gradients using the following matrix: [0 -1 0; -1 0 1; 0 1 0].

Parameters

[in]	*input	Input grayscale image
[out]	*dx	Output gradient in the X direction (dx->w = input->w-2, dx->h = input->h-2)
[out]	*dy	Output gradient in the Y direction (dx->w = input->w-2, dx->h = input->h-2)

Definition at line 549 of file image.c.

References image_t::buf, image_t::h, and image_t::w.

Referenced by opticFlowLK(), and opticFlowLK_flat().

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◆ image_multiply()

int32_t image_multiply	(	struct image_t *	img_a,
		struct image_t *	img_b,
		struct image_t *	mult
	)

Calculate the multiplication between two images and return the error This will only work with image gradients.

Parameters

[in]	*img_a	The image to multiply
[in]	*img_b	The image to multiply with
[out]	*mult	The image multiplication (if not needed can be NULL)

Returns: The sum of the multiplcation

Definition at line 643 of file image.c.

References image_t::buf, image_t::h, and image_t::w.

Referenced by opticFlowLK(), and opticFlowLK_flat().

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◆ image_show_flow()

void image_show_flow	(	struct image_t *	img,
		struct flow_t *	vectors,
		uint16_t	points_cnt,
		uint8_t	subpixel_factor
	)

Definition at line 726 of file image.c.

References image_show_flow_color().

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◆ image_show_flow_color()

void image_show_flow_color	(	struct image_t *	img,
		struct flow_t *	vectors,
		uint16_t	points_cnt,
		uint8_t	subpixel_factor,
		const uint8_t *	color,
		const uint8_t *	bad_color
	)

Shows the flow from a specific point to a new point This works on YUV422 and Grayscale images.

Parameters

[in,out]	*img	The image to show the flow on
[in]	*vectors	The flow vectors to show
[in]	*points_cnt	The amount of points and vectors to show
[in]	subpixel_factor
[in]	color	color for good vectors
[in]	bad_color	color for bad vectors

Definition at line 743 of file image.c.

References flow_t::flow_x, flow_t::flow_y, image_draw_crosshair(), image_draw_line_color(), LARGE_FLOW_ERROR, flow_t::pos, point_t::x, and point_t::y.

Referenced by calc_fast9_lukas_kanade(), and image_show_flow().

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◆ image_show_points()

void image_show_points	(	struct image_t *	img,
		struct point_t *	points,
		uint16_t	points_cnt
	)

Show points in an image by coloring them through giving the pixels the maximum value.

This works with YUV422 and grayscale images

Parameters

[in,out]	*img	The image to place the points on
[in]	*points	The points to sohw
[in]	*points_cnt	The amount of points to show

Definition at line 679 of file image.c.

References image_show_points_color().

Referenced by calc_fast9_lukas_kanade().

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◆ image_show_points_color()

void image_show_points_color	(	struct image_t *	img,
		struct point_t *	points,
		uint16_t	points_cnt,
		uint8_t *	color
	)

Show points in an image by coloring them through giving the pixels the maximum value.

This works with YUV422 and grayscale images

Parameters

[in,out]	*img	The image to place the points on
[in]	*points	The points to show
[in]	*points_cnt	The amount of points to show
[in]	*color	The color of the points as a [U, Y1, V, Y2] uint8_t array, or a uint8_t value pointer for grayscale images. Example colors: white = {127, 255, 127, 255}, green = {0, 127, 0, 127};

Definition at line 701 of file image.c.

References image_t::buf, idx, image_draw_crosshair(), IMAGE_YUV422, image_t::type, image_t::w, point_t::x, and point_t::y.

Referenced by image_show_points().

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◆ image_subpixel_window()

void image_subpixel_window	(	struct image_t *	input,
		struct image_t *	output,
		struct point_t *	center,
		uint32_t	subpixel_factor,
		uint8_t	border_size
	)

This outputs a subpixel window image in grayscale Currently only works with Grayscale images as input but could be upgraded to also support YUV422 images.

You can and should only ask a subpixel window of a center point that is w/2 pixels away from the edges

Parameters

[in]	*input	Input image (grayscale only)
[out]	*output	Window output (width and height is used to calculate the window size)
[in]	*center	Center point in subpixel coordinates
[in]	subpixel_factor	The subpixel factor per pixel
[in]	border_size	- amount of padding around image. Padding is made by reflecting image elements at the edge Example: f e d c b a \| a b c d e f \| f e d c b a

Definition at line 491 of file image.c.

References image_t::buf, image_t::h, image_t::w, point_t::x, and point_t::y.

Referenced by opticFlowLK(), and opticFlowLK_flat().

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◆ image_switch()

void image_switch	(	struct image_t *	a,
		struct image_t *	b
	)

This will switch image *a and *b This is faster as image_copy because it doesn't copy the whole image buffer.

Parameters

[in,out]	*a	The image to switch
[in,out]	*b	The image to switch with

Definition at line 112 of file image.c.

References b.

Referenced by calc_fast9_lukas_kanade().

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◆ image_to_grayscale()

void image_to_grayscale	(	struct image_t *	input,
		struct image_t *	output
	)

Convert an image to grayscale.

Depending on the output type the U/V bytes are removed

Parameters

[in]	*input	The input image (Needs to be YUV422)
[out]	*output	The output image

Definition at line 131 of file image.c.

References image_t::buf, dest, image_t::eulers, image_t::h, IMAGE_YUV422, image_t::pprz_ts, image_t::ts, image_t::type, and image_t::w.

Referenced by calc_fast9_lukas_kanade(), cv_window_func(), and detect_window().

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◆ image_yuv422_colorfilt()

uint16_t image_yuv422_colorfilt	(	struct image_t *	input,
		struct image_t *	output,
		uint8_t	y_m,
		uint8_t	y_M,
		uint8_t	u_m,
		uint8_t	u_M,
		uint8_t	v_m,
		uint8_t	v_M
	)

Filter colors in an YUV422 image.

Parameters

[in]	*input	The input image to filter
[out]	*output	The filtered output image
[in]	y_m	The Y minimum value
[in]	y_M	The Y maximum value
[in]	u_m	The U minimum value
[in]	u_M	The U maximum value
[in]	v_m	The V minimum value
[in]	v_M	The V maximum value

Returns: The amount of filtered pixels

Definition at line 173 of file image.c.

References image_t::buf, dest, image_t::h, image_t::ts, and image_t::w.

Referenced by colorfilter_func(), detect_gate_func(), and snake_gate_detection().

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◆ image_yuv422_downsample()

void image_yuv422_downsample	(	struct image_t *	input,
		struct image_t *	output,
		uint8_t	downsample
	)

Simplified high-speed low CPU downsample function without averaging downsample factor must be 1, 2, 4, 8 ...

2^X image of type UYVY expected. Only one color UV per 2 pixels

we keep the UV color of the first pixel pair and sample the intensity evenly 1-3-5-7-... or 1-5-9-...

input: u1y1 v1y2 u3y3 v3y4 u5y5 v5y6 u7y7 v7y8 ... downsample=1 u1y1 v1y2 u3y3 v3y4 u5y5 v5y6 u7y7 v7y8 ... downsample=2 u1y1v1 (skip2) y3 (skip2) u5y5v5 (skip2) y7 (skip2) ... downsample=4 u1y1v1 (skip6) y5 (skip6) ...

Parameters

[in]	*input	The input YUV422 image
[out]	*output	The downscaled YUV422 image
[in]	downsample	The downsample factor (must be downsample=2^X)

Definition at line 318 of file image.c.

References image_t::buf, dest, image_t::h, image_t::ts, image_t::type, and image_t::w.

Referenced by viewvideo_function().

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◆ ker_mul_3x3()

uint8_t ker_mul_3x3	(	uint8_t const *	source,
		int_fast8_t const *	kernel,
		uint8_t	total,
		uint8_t	setting,
		int	width,
		int	YUV
	)

Kernel multiplication for a 3 x 3 kernel.

Pixels outside the edges are taken to be 0.

Parameters

[in]	source	The source values
[in]	kernel	The kernel values
	total	The kernel total, set to 1 if the result should not be normalised
	setting	Variable is used to indicate which pixels the multiplication uses at a specific edges.
	YUV	A bool that adds an extra pixel offset if the YUV format is used.

Definition at line 1013 of file image.c.

References offset.

Referenced by image_convolution_3x3().

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◆ pyramid_build()

void pyramid_build	(	struct image_t *	input,
		struct image_t *	output_array,
		uint8_t	pyr_level,
		uint16_t	border_size
	)

This function populates given array of image_t structs with wanted number of padded pyramids based on given input.

Parameters

[in]	*input	- input image (grayscale only)
[out]	*output	- array of image_t structs containing image pyiramid levels. Level zero contains original image, followed by `pyr_level` of pyramid.
[in]	pyr_level	- number of pyramids to be built. If 0, original image is padded and outputed.
[in]	border_size	- amount of padding around image. Padding is made by reflecting image elements at the edge Example: f e d c b a \| a b c d e f \| f e d c b a

Definition at line 464 of file image.c.

References image_add_border(), image_free(), and pyramid_next_level().

Referenced by opticFlowLK().

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◆ pyramid_next_level()

void pyramid_next_level	(	struct image_t *	input,
		struct image_t *	output,
		uint8_t	border_size
	)

This function takes previous padded pyramid level and outputs next level of pyramid without padding.

For calculating new pixel value 3x3 Gaussian filter matrix is used: [1/4 1/2 1/4]' x [1/4 1/2 1/4] Blur and downsample is performed with two 1D convolutions (horizontal then vertical) instead of a single 2D convolution, to increase performance

Parameters

[in]	*input	- input image (grayscale only)
[out]	*output	- the output image
[in]	border_size	- amount of padding around image. Padding is made by reflecting image elements at the edge Example: f e d c b a \| a b c d e f \| f e d c b a

Definition at line 414 of file image.c.

References image_t::buf, image_t::h, image_create(), image_t::type, and image_t::w.

Referenced by pyramid_build().

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◆ set_color_yuv422()

void set_color_yuv422	(	struct image_t *	im,
		int	x,
		int	y,
		uint8_t	Y,
		uint8_t	U,
		uint8_t	V
	)

Sets Y,U,V for a single pixel.

Parameters

[in]	im	The input image to filter
[in]	x	The x-coordinate of the pixel
[in]	y	The y-coordinate of the pixel
[in]	Y	The Y-value.
[in]	U	The U-value.
[in]	V	The V value

Definition at line 279 of file image.c.

References image_t::buf, image_t::h, image_t::w, and mesonh.mesonh_atmosphere::Y.

Data Structures

Enumerations

Functions

Detailed Description

Data Structure Documentation

◆ image_t

◆ point_t

◆ point3d_t

◆ flow_t

◆ img_size_t

◆ crop_t

Enumeration Type Documentation

◆ image_type

Function Documentation

◆ check_color_yuv422()

◆ image_add_border()

◆ image_calculate_g()

◆ image_convolution_3x3()

◆ image_copy()

◆ image_create()

◆ image_difference()

◆ image_draw_crosshair()

◆ image_draw_line()

◆ image_draw_line_color()

◆ image_draw_rectangle()

◆ image_free()

◆ image_gradient_pixel()

◆ image_gradients()

◆ image_multiply()

◆ image_show_flow()

◆ image_show_flow_color()

◆ image_show_points()

◆ image_show_points_color()

◆ image_subpixel_window()

◆ image_switch()

◆ image_to_grayscale()

◆ image_yuv422_colorfilt()

◆ image_yuv422_downsample()

◆ ker_mul_3x3()

◆ pyramid_build()

◆ pyramid_next_level()

◆ set_color_yuv422()