Useful functions for working with images

Classes
class	mx::improc::sourceFinder< _realT >
	Find stars in an image by SNR thresholding. More...

Functions
template<typename realT>
int	mx::improc::circleOuterpix (realT &x0, realT &y0, realT &avgr0, realT &avgx, realT &avgy, realT &avgr, eigenImage< realT > &circ, const eigenImage< realT > &masked)
	Find the center and the outermost pixels of a circular mask, giving an estimate of the radius.
template<typename realT>
constexpr realT	mx::improc::invalidNumber ()
	Return the configured invalid image-pixel value.
template<typename realT>
bool	mx::improc::isInvalidPixel (realT value)
	Check whether a value represents an invalid image pixel.
template<typename realT>
int	mx::improc::reflectImageCoords (int &x1, int &y1, int x0, int y0, realT xc, realT yc)
	Reflect pixel coordinates across the given center pixel.
void *	mx::improc::imcpy (void dest, void src, size_t width, size_t height, size_t szof)
	Copy one image to another, with no transformation.
void *	mx::improc::imcpy_flipUD (void dest, void src, size_t width, size_t height, size_t szof)
	Copy one image to another, flipping up-down.
void *	mx::improc::imcpy_flipLR (void dest, void src, size_t width, size_t height, size_t szof)
	Copy one image to another, flipping left-right.
void *	mx::improc::imcpy_flipUDLR (void dest, void src, size_t width, size_t height, size_t szof)
	Copy one image to another, flipping up-down and left-right.

Function Documentation

◆ circleOuterpix()

template<typename realT>

int mx::improc::circleOuterpix	(	realT &	x0,
		realT &	y0,
		realT &	avgr0,
		realT &	avgx,
		realT &	avgy,
		realT &	avgr,
		eigenImage< realT > &	circ,
		const eigenImage< realT > &	masked )

Find the center and the outermost pixels of a circular mask, giving an estimate of the radius.

Takes a 1/0 mask of a filled circle or annulus, and calculates the center coordinate by center-of-light, then finds the outermost 1 pixel in each row and column. Calculates the average radius of these pixels w.r.t. to the c.o.l. coords, as well as w.r.t. the average coords of the outer pixels themselves.

Also produces an image containing the outer pixels.

Returns: 0 on success

Template Parameters

realT the real floating-point type for calculations

Parameters

y0	< [out] x coord of center of the mask by center-of-light
avgr0	< [out] y coord of center of the mask by center-of-light
avgx	< [out] average radius of edge pixels w.r.t. center-of-light
avgy	< [out] x coord of center of the mask by average edge pixel
avgr	< [out] y coord of center of the mask by average edge pixel
circ	< [out] average radius of edge pixels w.r.t. to average edge pixel
masked	< [out] image showing the edge pixels with value 1, all other pixels 0. Resized. < [in] an image with a (roughly) circular mask of 1s

Definition at line 55 of file circleOuterpix.hpp.

References imageCenterOfLight().

◆ imcpy()

void * mx::improc::imcpy	(	void *	dest,
		void *	src,
		size_t	width,
		size_t	height,
		size_t	szof )

Copy one image to another, with no transformation.

This is merely memcpy

Returns: dest

Parameters

[out]	dest	the address of the first pixel in the destination image
[in]	src	the address of the first pixel in the source image
[in]	width	the width in pixels of size szof
[in]	height	the height in pixels of size szof
[in]	szof	the size in bytes of a one pixel

Definition at line 35 of file imageUtils.cpp.

◆ imcpy_flipLR()

void * mx::improc::imcpy_flipLR	(	void *	dest,
		void *	src,
		size_t	width,
		size_t	height,
		size_t	szof )

Copy one image to another, flipping left-right.

Returns: dest

Parameters

[out]	dest	the address of the first pixel in the destination image
[in]	src	the address of the first pixel in the source image
[in]	width	the width in pixels of size szof
[in]	height	the height in pixels of size szof
[in]	szof	the size in bytes of a one pixel

Definition at line 50 of file imageUtils.cpp.

◆ imcpy_flipUD()

void * mx::improc::imcpy_flipUD	(	void *	dest,
		void *	src,
		size_t	width,
		size_t	height,
		size_t	szof )

Copy one image to another, flipping up-down.

This is a reversed row-by-row memcpy

Returns: dest

Parameters

[out]	dest	the address of the first pixel in the destination image
[in]	src	the address of the first pixel in the source image
[in]	width	the width in pixels of size szof
[in]	height	the height in pixels of size szof
[in]	szof	the size in bytes of a one pixel

Definition at line 40 of file imageUtils.cpp.

◆ imcpy_flipUDLR()

void * mx::improc::imcpy_flipUDLR	(	void *	dest,
		void *	src,
		size_t	width,
		size_t	height,
		size_t	szof )

Copy one image to another, flipping up-down and left-right.

Returns: dest

Parameters

[out]	dest	the address of the first pixel in the destination image
[in]	src	the address of the first pixel in the source image
[in]	width	the width in pixels of size szof
[in]	height	the height in pixels of size szof
[in]	szof	the size in bytes of a one pixel

Definition at line 118 of file imageUtils.cpp.

◆ invalidNumber()

template<typename realT>

realT mx::improc::invalidNumber ( )

constexpr

Return the configured invalid image-pixel value.

The default is a quiet NaN so FITS and image-display tools recognize invalid pixels. Defining MXLIB_INVALID_NUMBER_VALUE at compile time selects that finite value instead. CMake propagates its MXLIB_INVALID_NUMBER_VALUE cache setting through the installed pkg-config metadata.

Returns: the invalid-pixel value for realT

Definition at line 85 of file imageUtils.hpp.

Referenced by isInvalidPixel(), mx::improc::eigenCube< dataT >::mean(), mx::improc::eigenCube< dataT >::mean(), mx::improc::eigenCube< dataT >::median(), mx::improc::eigenCube< dataT >::sigmaMean(), mx::improc::eigenCube< dataT >::sigmaMean(), and TEST_CASE().

◆ isInvalidPixel()

template<typename realT>

bool mx::improc::isInvalidPixel ( realT value )

Check whether a value represents an invalid image pixel.

Detects the configured mxlib invalid-number value as well as NaN and positive or negative infinity. The non-finite classification remains reliable under finite-math-only optimization.

Returns: true if value is invalid, otherwise false.

Parameters

[in] value value to test

Definition at line 103 of file imageUtils.hpp.

References invalidNumber(), and mx::math::isFinite().

Referenced by TEST_CASE(), unitTest::improcTest::eigenCubeTest::TEST_CASE(), unitTest::improcTest::eigenCubeTest::TEST_CASE(), unitTest::improcTest::eigenCubeTest::TEST_CASE(), zeroNaNCube(), and zeroNaNs().

◆ reflectImageCoords()

template<typename realT>

int mx::improc::reflectImageCoords	(	int &	x1,
		int &	y1,
		int	x0,
		int	y0,
		realT	xc,
		realT	yc )

Reflect pixel coordinates across the given center pixel.

Parameters

[out]	x1	the reflected x coordinate
[out]	y1	the reflected y coordinate
[in]	x0	the input x coordinate
[in]	y0	the input y coordinate
[in]	xc	the center pixel x coordinate
[in]	yc	the center pixel y coordinate

Definition at line 118 of file imageUtils.hpp.

Referenced by reflectImageIndices().

Classes

Functions

Function Documentation

◆ circleOuterpix()

◆ imcpy()

◆ imcpy_flipLR()

◆ imcpy_flipUD()

◆ imcpy_flipUDLR()

◆ invalidNumber()

◆ isInvalidPixel()

◆ reflectImageCoords()