High level functions to handle apertures

Functions
void	cpl_apertures_dump (const cpl_apertures *self, FILE *fp)
	Dump a cpl_apertures to an opened file pointer.
cpl_apertures *	cpl_apertures_extract (const cpl_image *self, const cpl_vector *sigmas, cpl_size *pisigma)
	Simple detection of apertures in an image.
cpl_apertures *	cpl_apertures_extract_mask (const cpl_image *self, const cpl_mask *selection)
	Simple apertures creation from a user supplied selction mask.
cpl_apertures *	cpl_apertures_extract_sigma (const cpl_image *self, double sigma)
	Simple apertures detection in an image using a provided sigma.
cpl_apertures *	cpl_apertures_extract_window (const cpl_image *self, const cpl_vector *sigmas, cpl_size llx, cpl_size lly, cpl_size urx, cpl_size ury, cpl_size *pisigma)
	Simple detection of apertures in an image window.
cpl_size	cpl_apertures_get_bottom (const cpl_apertures *self, cpl_size ind)
	Get the bottommost y position in an aperture.
cpl_size	cpl_apertures_get_bottom_x (const cpl_apertures *self, cpl_size ind)
	Get the x position of the bottommost y position in an aperture.
double	cpl_apertures_get_centroid_x (const cpl_apertures *self, cpl_size ind)
	Get the X-centroid of an aperture.
double	cpl_apertures_get_centroid_y (const cpl_apertures *self, cpl_size ind)
	Get the Y-centroid of an aperture.
double	cpl_apertures_get_flux (const cpl_apertures *self, cpl_size ind)
	Get the flux of an aperture.
cpl_bivector *	cpl_apertures_get_fwhm (const cpl_image *self, const cpl_apertures *aperts)
	Compute FWHM values in x and y for a list of apertures.
cpl_size	cpl_apertures_get_left (const cpl_apertures *self, cpl_size ind)
	Get the leftmost x position in an aperture.
cpl_size	cpl_apertures_get_left_y (const cpl_apertures *self, cpl_size ind)
	Get the y position of the leftmost x position in an aperture.
double	cpl_apertures_get_max (const cpl_apertures *self, cpl_size ind)
	Get the maximum value of an aperture.
double	cpl_apertures_get_max_x (const cpl_apertures *self, cpl_size ind)
	Get the average X-position of an aperture.
double	cpl_apertures_get_max_y (const cpl_apertures *self, cpl_size ind)
	Get the average Y-position of an aperture.
cpl_size	cpl_apertures_get_maxpos_x (const cpl_apertures *self, cpl_size ind)
	Get the X-position of the aperture maximum value.
cpl_size	cpl_apertures_get_maxpos_y (const cpl_apertures *self, cpl_size ind)
	Get the Y-position of the aperture maximum value.
double	cpl_apertures_get_mean (const cpl_apertures *self, cpl_size ind)
	Get the mean value of an aperture.
double	cpl_apertures_get_median (const cpl_apertures *self, cpl_size ind)
	Get the median value of an aperture.
double	cpl_apertures_get_min (const cpl_apertures *self, cpl_size ind)
	Get the minimum value of an aperture.
cpl_size	cpl_apertures_get_minpos_x (const cpl_apertures *self, cpl_size ind)
	Get the X-position of the aperture minimum value.
cpl_size	cpl_apertures_get_minpos_y (const cpl_apertures *self, cpl_size ind)
	Get the Y-position of the aperture minimum value.
cpl_size	cpl_apertures_get_npix (const cpl_apertures *self, cpl_size ind)
	Get the number of pixels of an aperture.
double	cpl_apertures_get_pos_x (const cpl_apertures *self, cpl_size ind)
	Get the average X-position of an aperture.
double	cpl_apertures_get_pos_y (const cpl_apertures *self, cpl_size ind)
	Get the average Y-position of an aperture.
cpl_size	cpl_apertures_get_right (const cpl_apertures *self, cpl_size ind)
	Get the rightmost x position in an aperture.
cpl_size	cpl_apertures_get_right_y (const cpl_apertures *self, cpl_size ind)
	Get the y position of the rightmost x position in an aperture.
cpl_size	cpl_apertures_get_size (const cpl_apertures *self)
	Get the number of apertures.
double	cpl_apertures_get_stdev (const cpl_apertures *self, cpl_size ind)
	Get the standard deviation of an aperture.
cpl_size	cpl_apertures_get_top (const cpl_apertures *self, cpl_size ind)
	Get the topmost y position in an aperture.
cpl_size	cpl_apertures_get_top_x (const cpl_apertures *self, cpl_size ind)
	Get the x position of the topmost y position in an aperture.
cpl_apertures *	cpl_apertures_new_from_image (const cpl_image *self, const cpl_image *lab)
	Compute statistics on selected apertures.
cpl_error_code	cpl_apertures_sort_by_flux (cpl_apertures *self)
	Sort by decreasing aperture flux.
cpl_error_code	cpl_apertures_sort_by_max (cpl_apertures *self)
	Sort by decreasing aperture peak value.
cpl_error_code	cpl_apertures_sort_by_npix (cpl_apertures *self)
	Sort by decreasing aperture size.

Detailed Description

The aperture object contains a list of zones in an image. It is typically used to contain the results of an objects detection, or if one wants to work on a very specific zone in an image.

This module provides functions to handle cpl_apertures.

Function Documentation

void cpl_apertures_dump	(	const cpl_apertures *	self,
		FILE *	fp
	)

Dump a cpl_apertures to an opened file pointer.

Parameters

self	The cpl_apertures to dump
fp	File pointer, may use stdout or stderr

Returns

void

This function dumps all information in a cpl_apertures to the passed file pointer. If the object is unallocated or contains nothing, this function does nothing.

cpl_apertures* cpl_apertures_extract	(	const cpl_image *	self,
		const cpl_vector *	sigmas,
		cpl_size *	pisigma
	)

Simple detection of apertures in an image.

Parameters

self	The image to process
sigmas	Positive, decreasing sigmas to apply
pisigma	Index of the sigma that was used or unchanged on error

Returns

The detected apertures or NULL on error

See Also

cpl_apertures_extract_sigma()

pisigma may be NULL.

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if self or sigmas is NULL
• CPL_ERROR_DATA_NOT_FOUND if the apertures cannot be detected

cpl_apertures* cpl_apertures_extract_mask	(	const cpl_image *	self,
		const cpl_mask *	selection
	)

Simple apertures creation from a user supplied selction mask.

Parameters

self	The image to process
selection	The mask of selected pixels

Returns

The list of detected apertures or NULL if nothing detected or on error.

See Also

cpl_image_labelise_mask_create(), cpl_apertures_new_from_image()

The values selected for inclusion in the apertures must have the non-zero value in the selection mask, and must not be flagged as bad in the bad pixel map of the image.

The input image type can be CPL_TYPE_DOUBLE, CPL_TYPE_FLOAT or CPL_TYPE_INT.

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_INCOMPATIBLE_INPUT if self and selection have different sizes.
• CPL_ERROR_TYPE_MISMATCH if self is of a complex type
• CPL_ERROR_DATA_NOT_FOUND if the selection mask is empty

cpl_apertures* cpl_apertures_extract_sigma	(	const cpl_image *	self,
		double	sigma
	)

Simple apertures detection in an image using a provided sigma.

Parameters

self	The image to process
sigma	Detection level

Returns

The list of detected apertures or NULL on error

Note

In order to avoid (the potentially many) detections of small objects the mask of detected pixels is subjected to a 3x3 morphological opening filter.

See Also

cpl_apertures_extract_mask(), cpl_mask_filter()

The threshold used for the detection is the median plus the average distance to the median times sigma.

The input image type can be CPL_TYPE_DOUBLE, CPL_TYPE_FLOAT or CPL_TYPE_INT.

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_ILLEGAL_INPUT if sigma is non-positive
• CPL_ERROR_TYPE_MISMATCH if self is of a complex type
• CPL_ERROR_DATA_NOT_FOUND if the no apertures are found

cpl_apertures* cpl_apertures_extract_window	(	const cpl_image *	self,
		const cpl_vector *	sigmas,
		cpl_size	llx,
		cpl_size	lly,
		cpl_size	urx,
		cpl_size	ury,
		cpl_size *	pisigma
	)

Simple detection of apertures in an image window.

Parameters

self	The image to process
sigmas	Positive, decreasing sigmas to apply
llx	Lower left x position (FITS convention)
lly	Lower left y position (FITS convention)
urx	Upper right x position (FITS convention)
ury	Upper right y position (FITS convention)
pisigma	Index of the sigma that was used or undefined on error

Returns

The list of detected apertures or NULL on error

See Also

cpl_apertures_extract()

cpl_image_extract()

cpl_size cpl_apertures_get_bottom	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the bottommost y position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the bottommost y position in the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_bottom_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the x position of the bottommost y position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the bottommost x position of the aperture or negative on error

Note

An aperture may have multiple bottom x positions, in which case one of these is returned.

See Also

cpl_apertures_get_maxpos_x()

double cpl_apertures_get_centroid_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the X-centroid of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The X-centroid position of the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

For a concave aperture the centroid may not belong to the aperture.

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_ILLEGAL_INPUT if ind is non-positive
• CPL_ERROR_ACCESS_OUT_OF_RANGE if ind exceeds the number of apertures in self

double cpl_apertures_get_centroid_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the Y-centroid of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The X-centroid position of the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_centroid_x()

double cpl_apertures_get_flux	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the flux of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The flux of the aperture or undefined on error

See Also

cpl_apertures_get_max()

cpl_bivector* cpl_apertures_get_fwhm	(	const cpl_image *	self,
		const cpl_apertures *	aperts
	)

Compute FWHM values in x and y for a list of apertures.

Parameters

self	The image to process
aperts	The list of apertures

Returns

A newly allocated object containing the fwhms in x and y or NULL

See Also

cpl_image_get_fwhm()

Deprecated:

Replace this call with a loop over cpl_image_get_fwhm()

cpl_size cpl_apertures_get_left	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the leftmost x position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the leftmost x position of the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_left_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the y position of the leftmost x position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the y position of the leftmost x position or negative on error

Note

An aperture may have multiple leftmost x positions, in which case one of these is returned.

See Also

cpl_apertures_get_maxpos_x()

double cpl_apertures_get_max	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the maximum value of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The maximum value of the aperture or undefined on error

Note

In case of an error the _cpl_error_code_ code is set

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_ILLEGAL_INPUT if ind is non-positive
• CPL_ERROR_ACCESS_OUT_OF_RANGE if ind exceeds the number of apertures in self

double cpl_apertures_get_max_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the average X-position of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The average X-position of the aperture or negative on error

Deprecated:

Replace this function with cpl_apertures_get_pos_x()

double cpl_apertures_get_max_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the average Y-position of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The average Y-position of the aperture or negative on error

Deprecated:

Replace this function with cpl_apertures_get_pos_y()

cpl_size cpl_apertures_get_maxpos_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the X-position of the aperture maximum value.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The X-position of the aperture maximum value or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_centroid_x()

cpl_size cpl_apertures_get_maxpos_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the Y-position of the aperture maximum value.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The Y-position of the aperture maximum value or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

double cpl_apertures_get_mean	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the mean value of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The mean value of the aperture or undefined on error

See Also

cpl_apertures_get_max()

double cpl_apertures_get_median	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the median value of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The median value of the aperture or undefined on error

See Also

cpl_apertures_get_max()

double cpl_apertures_get_min	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the minimum value of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The minimum value of the aperture or undefined on error

See Also

cpl_apertures_get_max()

cpl_size cpl_apertures_get_minpos_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the X-position of the aperture minimum value.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The X-position of the aperture minimum value or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_minpos_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the Y-position of the aperture minimum value.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The Y-position of the aperture minimum value or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_minpos_x()

cpl_size cpl_apertures_get_npix	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the number of pixels of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The number of pixels of the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_ILLEGAL_INPUT if ind is non-positive
• CPL_ERROR_ACCESS_OUT_OF_RANGE if ind exceeds the number of apertures in self

double cpl_apertures_get_pos_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the average X-position of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The average X-position of the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_centroid_x()

double cpl_apertures_get_pos_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the average Y-position of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The average Y-position of the aperture or negative on error

See Also

cpl_apertures_get_pos_x()

cpl_size cpl_apertures_get_right	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the rightmost x position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the rightmost x position in an aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_right_y	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the y position of the rightmost x position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the y position of the rightmost x position or negative on error

Note

An aperture may have multiple rightmost x positions, in which case one of these is returned.

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_size

(

const cpl_apertures *

self

)

Get the number of apertures.

Parameters

self	The cpl_apertures object

Returns

The number of apertures or -1 on error

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL

double cpl_apertures_get_stdev	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the standard deviation of an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

The standard deviation of the aperture or negative on error

See Also

cpl_apertures_get_max()

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_ILLEGAL_INPUT if ind is non-positive
• CPL_ERROR_ACCESS_OUT_OF_RANGE if ind exceeds the number of apertures in self
• CPL_ERROR_DATA_NOT_FOUND if the aperture comprises less than two pixels

cpl_size cpl_apertures_get_top	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the topmost y position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the topmost y position in the aperture or negative on error

Note

In case of an error the _cpl_error_code_ code is set

See Also

cpl_apertures_get_maxpos_x()

cpl_size cpl_apertures_get_top_x	(	const cpl_apertures *	self,
		cpl_size	ind
	)

Get the x position of the topmost y position in an aperture.

Parameters

self	The cpl_apertures object
ind	The aperture index (1 for the first one)

Returns

the x position of the topmost y position or negative on error

Note

An aperture may have multiple topmost x positions, in which case one of these is returned.

See Also

cpl_apertures_get_maxpos_x()

cpl_apertures* cpl_apertures_new_from_image	(	const cpl_image *	self,
		const cpl_image *	lab
	)

Compute statistics on selected apertures.

Parameters

self	Reference image
lab	Labelized image (of type CPL_TYPE_INT)

Returns

An CPL apertures object or NULL on error

Note

The returned object must be deleted using cpl_apertures_delete().

See Also

cpl_image_labelise_mask_create()

The labelized image must contain at least one pixel for each value from 1 to the maximum value in the image.

For the centroiding computation of an aperture, if some pixels have values lower or equal to 0, all the values of the aperture are locally shifted such as the minimum value of the aperture has a value of epsilon. The centroid is then computed on these positive values. In principle, centroid should always be computed on positive values, this is done to avoid raising an error in case the caller of the function wants to use it on negative values images without caring about the centroid results. In such cases, the centroid result would be meaningful, but slightly depend on the hardcoded value chosen for epsilon (1e-10).

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL
• CPL_ERROR_TYPE_MISMATCH if lab is not of type CPL_TYPE_INT or if self is of a complex type
• CPL_ERROR_ILLEGAL_INPUT if lab has a negative value or zero maximum
• CPL_ERROR_INCOMPATIBLE_INPUT if lab and self have different sizes.
• CPL_ERROR_DATA_NOT_FOUND if one of the lab values is missing.

cpl_error_code cpl_apertures_sort_by_flux

(

cpl_apertures *

self

)

Sort by decreasing aperture flux.

Parameters

self	Apertures to sort (MODIFIED)

Returns

the _cpl_error_code_ or CPL_ERROR_NONE

See Also

cpl_apertures_sort_by_npix()

cpl_error_code cpl_apertures_sort_by_max

(

cpl_apertures *

self

)

Sort by decreasing aperture peak value.

Parameters

self	Apertures to sort (MODIFIED)

Returns

the _cpl_error_code_ or CPL_ERROR_NONE

See Also

cpl_apertures_sort_by_npix()

cpl_error_code cpl_apertures_sort_by_npix

(

cpl_apertures *

self

)

Sort by decreasing aperture size.

Parameters

self	Apertures to sort (MODIFIED)

Returns

CPL_ERROR_NONE or the relevant _cpl_error_code_

Possible _cpl_error_code_ set in this function:

• CPL_ERROR_NULL_INPUT if an input pointer is NULL