Definitions for image utility functions. More...

#include <jwsc/config.h>
#include <stdlib.h>
#include <inttypes.h>
#include <math.h>
#include <assert.h>
#include "jwsc/base/error.h"
#include "jwsc/matrix/matrix.h"
#include "jwsc/filter/2d.h"
#include "jwsc/image/image.h"
#include "jwsc/image/image_util.h"

Include dependency graph for image_util.c:

Go to the source code of this file.

Functions
Error *	crop_image_f (Image_f *img_out, const Image_f img_in, uint32_t row, uint32_t col, uint32_t num_rows, uint32_t num_cols)
	Crops a single precision image into a padding region.
down_sample_image
Down samples an image.
Error *	down_sample_image_f (Image_f *img_out, const Image_f img_in, float row_factor, float col_factor)
	Down samples a single precision image.
extend_image
Extends an image into a padding region.
void	extend_image_f (Image_f *img_out, const Image_f img_in, uint32_t row_padding, uint32_t col_padding)
	Extends a single precision image into a padding region.
threshold_image
Thresholds an image.
void	threshold_image_f (Matrix_f *mat_out, const Image_f img_in, float t)
	Thresholds a single precision image.
threshold_matrix
Thresholds a matrix.
void	threshold_matrix_f (Matrix_f *mat_out, const Matrix_f mat_in, float t)
	Thresholds a single precision matrix.
dynamically_threshold_image
Dynamically thresholds a image.
void	dynamically_threshold_image_f (Matrix_f *mat_out, const Image_f img_in)
	Dynamically thresholds a single precision image.
dynamically_threshold_matrix
Dynamically thresholds a matrix.
void	dynamically_threshold_matrix_f (Matrix_f *mat_out, const Matrix_f mat_in)
	Dynamically thresholds a single precision matrix.

Detailed Description

Definitions for image utility functions.

Author:: Joseph Schlecht

License:: Creative Commons BY-NC-SA 3.0

Definition in file image_util.c.

Function Documentation

Error* down_sample_image_f	(	Image_f **	img_out,
		const Image_f *	img_in,
		float	row_factor,
		float	col_factor
	)

Down samples a single precision image.

Uses a Gaussian smoothing function to down sample.

Parameters:

img_out	Result parameter. If *img_out is NULL, an image is allocated; otherwise its space is re-used.
img_in	Image to down sample.
row_factor	Percentage of current number of rows to down sample the number of rows in the image to, in the range (0,1].
col_factor	Percentage of current number of columns to down sample the number of columns in the image to, in the range (0,1].

Returns:

On success, NULL is returned. On error, an Error is returned and *img_out is freed and set to NULL (if it is not img_in).

ERROR_INV_ARG Down sampling row_factor or col_factor are not in (0, 1].

Note:: If *img_out == img_in, then img_in is overwritten.

Definition at line 87 of file image_util.c.

void extend_image_f	(	Image_f **	img_out,
		const Image_f *	img_in,
		uint32_t	row_padding,
		uint32_t	col_padding
	)

Extends a single precision image into a padding region.

Parameters:

img_out	Result parameter. If *img_out is NULL, an image is allocated; otherwise its space is re-used.
img_in	Image to extend.
row_padding	Number or rows for padding on top and bottom.
col_padding	Number of columns for padding on left and right.

Note:: If *img_out == img_in, then img_in is overwritten.

Definition at line 273 of file image_util.c.

Error* crop_image_f	(	Image_f **	img_out,
		const Image_f *	img_in,
		uint32_t	row,
		uint32_t	col,
		uint32_t	num_rows,
		uint32_t	num_cols
	)

Crops a single precision image into a padding region.

Parameters:

img_out	Result parameter. If *img_out is NULL, an image is allocated; otherwise its space is re-used.
img_in	Image to crop.
row	First row to use in the cropped result.
col	First col to use in the cropped result.
num_rows	Number of rows to use in the cropped result.
num_cols	Number of cols to use in the cropped result.

Returns:

On success, NULL is returned. On error, an Error is returned and *img_out is freed and set to NULL (if it is not img_in).

ERROR_INV_ARG Region to crop is not within the input image.

Definition at line 361 of file image_util.c.

void threshold_image_f	(	Matrix_f **	mat_out,
		const Image_f *	img_in,
		float	t
	)

Thresholds a single precision image.

The image is converted to grayscale and thresholded with t as follows

    m[i,j] <  t : m[i,j] = 0
    m[i,j] >= t : m[i,j] = 1

Definition at line 438 of file image_util.c.

void threshold_matrix_f	(	Matrix_f **	mat_out,
		const Matrix_f *	mat_in,
		float	t
	)

Thresholds a single precision matrix.

The matrix is thresholded with t as follows

    m[i,j] <  t : m[i,j] = 0
    m[i,j] >= t : m[i,j] = 1

Definition at line 469 of file image_util.c.

void dynamically_threshold_image_f	(	Matrix_f **	mat_out,
		const Image_f *	img_in
	)

Dynamically thresholds a single precision image.

A threshold t is iteratively found as the average between the mean foreground and background values.

The image is converted to grayscale and thresholded with t as follows

    m[i,j] <  t : m[i,j] = 0
    m[i,j] >= t : m[i,j] = 1

Definition at line 523 of file image_util.c.

void dynamically_threshold_matrix_f	(	Matrix_f **	mat_out,
		const Matrix_f *	mat_in
	)

Dynamically thresholds a single precision matrix.

A threshold t is iteratively found as the average between the mean foreground and background values.

The matrix is thresholded with t as follows

    m[i,j] <  t : m[i,j] = 0
    m[i,j] >= t : m[i,j] = 1

Definition at line 556 of file image_util.c.

Functions

Detailed Description

Function Documentation