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

#include "std.h"
#include <sys/time.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	flow_t

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

Functions
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...

void	image_yuv422_downsample (struct image_t input, struct image_t output, uint16_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, uint16_t subpixel_factor)
	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_flow (struct image_t img, struct flow_t vectors, uint16_t points_cnt, uint8_t subpixel_factor)
	Shows the flow from a specific point to a new point This works on YUV422 and Grayscale images. More...

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

Detailed Description

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

Definition in file image.h.

Data Structure Documentation

struct image_t

Definition at line 42 of file image.h.

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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.
uint16_t	h	Image height.
struct timeval	ts	The timestamp of creation.
enum image_type	type	The image type.
uint16_t	w	Image width.

struct point_t

Definition at line 54 of file image.h.

Data Fields
uint16_t	x	The x coordinate of the point.
uint16_t	y	The y coordinate of the point.

struct flow_t

Definition at line 60 of file image.h.

Collaboration diagram for flow_t:

Data Fields
int16_t	flow_x	The x direction flow in subpixels.
int16_t	flow_y	The y direction flow in subpixels.
struct point_t	pos	The original position the flow comes from.

Enumeration Type Documentation

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)

Definition at line 34 of file image.h.

Function Documentation

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 325 of file image.c.

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

Referenced by opticFlowLK().

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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 77 of file image.c.

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

Referenced by opticflow_calc_frame().

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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 38 of file image.c.

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

Referenced by bebop_front_camera_thread(), cv_blob_locator_func(), cv_window_func(), detect_window(), opticflow_calc_init(), opticflow_module_calc(), opticFlowLK(), qrscan(), video_thread_function(), video_thread_periodic(), and viewvideo_function().

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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 357 of file image.c.

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

Referenced by opticFlowLK().

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

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

Definition at line 479 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 image_show_flow().

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void image_free ( struct image_t * img )

Free the image.

Parameters

[in] *img The image to free

Definition at line 63 of file image.c.

References image_t::buf.

Referenced by cv_blob_locator_func(), cv_window_func(), detect_window(), opticflow_module_calc(), opticFlowLK(), video_thread_function(), video_thread_periodic(), and viewvideo_function().

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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 302 of file image.c.

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

Referenced by opticFlowLK().

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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 395 of file image.c.

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

Referenced by opticFlowLK().

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

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

Definition at line 456 of file image.c.

References flow_t::flow_x, flow_t::flow_y, image_draw_line(), flow_t::pos, point_t::x, and point_t::y.

Referenced by opticflow_calc_frame().

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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 431 of file image.c.

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

Referenced by opticflow_calc_frame().

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void image_subpixel_window	(	struct image_t *	input,
		struct image_t *	output,
		struct point_t *	center,
		uint16_t	subpixel_factor
	)

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.

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

Definition at line 247 of file image.c.

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

Referenced by opticFlowLK().

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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 97 of file image.c.

Referenced by opticflow_calc_frame().

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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 116 of file image.c.

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

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

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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 149 of file image.c.

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

Referenced by colorfilter_func().

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void image_yuv422_downsample	(	struct image_t *	input,
		struct image_t *	output,
		uint16_t	downsample
	)

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

2^X image of typ 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 downsampel facter (must be downsample=2^X)

Definition at line 213 of file image.c.

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

Referenced by viewvideo_function().

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Data Structures

Enumerations

Functions

Detailed Description

Data Structure Documentation

Enumeration Type Documentation

Function Documentation