#include <visp3/core/vpImageTools.h>

Public Types
enum	vpImageInterpolationType { INTERPOLATION_NEAREST, INTERPOLATION_LINEAR, INTERPOLATION_CUBIC, INTERPOLATION_AREA }

Public Member Functions
template<class Type >
void	createSubImage (const vpImage< Type > &I, unsigned int roi_top, unsigned int roi_left, unsigned int roi_height, unsigned int roi_width, vpImage< Type > &crop)

template<class Type >
void	createSubImage (const vpImage< Type > &I, const vpRect &roi, vpImage< Type > &crop)

template<>
void	binarise (vpImage< unsigned char > &I, unsigned char threshold1, unsigned char threshold2, unsigned char value1, unsigned char value2, unsigned char value3, bool useLUT)

template<>
void	resizeBicubic (const vpImage< vpRGBa > &I, vpImage< vpRGBa > &Ires, unsigned int i, unsigned int j, float u, float v, float xFrac, float yFrac)

template<>
void	resizeBilinear (const vpImage< vpRGBa > &I, vpImage< vpRGBa > &Ires, unsigned int i, unsigned int j, float u, float v, float xFrac, float yFrac)

template<>
void	resize (const vpImage< unsigned char > &I, vpImage< unsigned char > &Ires, const vpImageInterpolationType &method, unsigned int)

template<>
void	resize (const vpImage< vpRGBa > &I, vpImage< vpRGBa > &Ires, const vpImageInterpolationType &method, unsigned int)

template<>
void	warpLinear (const vpImage< vpRGBa > &src, const vpMatrix &T, vpImage< vpRGBa > &dst, bool affine, bool centerCorner, bool fixedPoint)

Static Public Member Functions
template<class Type >
static void	binarise (vpImage< Type > &I, Type threshold1, Type threshold2, Type value1, Type value2, Type value3, bool useLUT=true)

static void	changeLUT (vpImage< unsigned char > &I, unsigned char A, unsigned char newA, unsigned char B, unsigned char newB)

template<class Type >
static void	crop (const vpImage< Type > &I, double roi_top, double roi_left, unsigned int roi_height, unsigned int roi_width, vpImage< Type > &crop, unsigned int v_scale=1, unsigned int h_scale=1)

static void	columnMean (const vpImage< double > &I, vpRowVector &result)

template<class Type >
static void	crop (const vpImage< Type > &I, const vpImagePoint &topLeft, unsigned int roi_height, unsigned int roi_width, vpImage< Type > &crop, unsigned int v_scale=1, unsigned int h_scale=1)

template<class Type >
static void	crop (const vpImage< Type > &I, const vpRect &roi, vpImage< Type > &crop, unsigned int v_scale=1, unsigned int h_scale=1)

template<class Type >
static void	crop (const unsigned char *bitmap, unsigned int width, unsigned int height, const vpRect &roi, vpImage< Type > &crop, unsigned int v_scale=1, unsigned int h_scale=1)

static void	extract (const vpImage< unsigned char > &Src, vpImage< unsigned char > &Dst, const vpRectOriented &r)

static void	extract (const vpImage< unsigned char > &Src, vpImage< double > &Dst, const vpRectOriented &r)

template<class Type >
static void	flip (const vpImage< Type > &I, vpImage< Type > &newI)

template<class Type >
static void	flip (vpImage< Type > &I)

static void	imageDifference (const vpImage< unsigned char > &I1, const vpImage< unsigned char > &I2, vpImage< unsigned char > &Idiff)

static void	imageDifference (const vpImage< vpRGBa > &I1, const vpImage< vpRGBa > &I2, vpImage< vpRGBa > &Idiff)

static void	imageDifferenceAbsolute (const vpImage< unsigned char > &I1, const vpImage< unsigned char > &I2, vpImage< unsigned char > &Idiff)

static void	imageDifferenceAbsolute (const vpImage< double > &I1, const vpImage< double > &I2, vpImage< double > &Idiff)

static void	imageDifferenceAbsolute (const vpImage< vpRGBa > &I1, const vpImage< vpRGBa > &I2, vpImage< vpRGBa > &Idiff)

static void	imageAdd (const vpImage< unsigned char > &I1, const vpImage< unsigned char > &I2, vpImage< unsigned char > &Ires, bool saturate=false)

static void	imageSubtract (const vpImage< unsigned char > &I1, const vpImage< unsigned char > &I2, vpImage< unsigned char > &Ires, bool saturate=false)

static void	initUndistortMap (const vpCameraParameters &cam, unsigned int width, unsigned int height, vpArray2D< int > &mapU, vpArray2D< int > &mapV, vpArray2D< float > &mapDu, vpArray2D< float > &mapDv)

static double	interpolate (const vpImage< unsigned char > &I, const vpImagePoint &point, const vpImageInterpolationType &method=INTERPOLATION_NEAREST)

static void	integralImage (const vpImage< unsigned char > &I, vpImage< double > &II, vpImage< double > &IIsq)

static double	normalizedCorrelation (const vpImage< double > &I1, const vpImage< double > &I2, bool useOptimized=true)

static void	normalize (vpImage< double > &I)

static void	remap (const vpImage< unsigned char > &I, const vpArray2D< int > &mapU, const vpArray2D< int > &mapV, const vpArray2D< float > &mapDu, const vpArray2D< float > &mapDv, vpImage< unsigned char > &Iundist)

static void	remap (const vpImage< vpRGBa > &I, const vpArray2D< int > &mapU, const vpArray2D< int > &mapV, const vpArray2D< float > &mapDu, const vpArray2D< float > &mapDv, vpImage< vpRGBa > &Iundist)

template<class Type >
static void	resize (const vpImage< Type > &I, vpImage< Type > &Ires, unsigned int width, unsigned int height, const vpImageInterpolationType &method=INTERPOLATION_NEAREST, unsigned int nThreads=0)

template<class Type >
static void	resize (const vpImage< Type > &I, vpImage< Type > &Ires, const vpImageInterpolationType &method=INTERPOLATION_NEAREST, unsigned int nThreads=0)

static void	templateMatching (const vpImage< unsigned char > &I, const vpImage< unsigned char > &I_tpl, vpImage< double > &I_score, unsigned int step_u, unsigned int step_v, bool useOptimized=true)

template<class Type >
static void	undistort (const vpImage< Type > &I, const vpCameraParameters &cam, vpImage< Type > &newI, unsigned int nThreads=2)

template<class Type >
static void	undistort (const vpImage< Type > &I, vpArray2D< int > mapU, vpArray2D< int > mapV, vpArray2D< float > mapDu, vpArray2D< float > mapDv, vpImage< Type > &newI)

template<class Type >
static void	warpImage (const vpImage< Type > &src, const vpMatrix &T, vpImage< Type > &dst, const vpImageInterpolationType &interpolation=INTERPOLATION_NEAREST, bool fixedPointArithmetic=true, bool pixelCenter=false)

Deprecated functions
template<class Type >
static vp_deprecated void	createSubImage (const vpImage< Type > &I, unsigned int i_sub, unsigned int j_sub, unsigned int nrow_sub, unsigned int ncol_sub, vpImage< Type > &S)

template<class Type >
static vp_deprecated void	createSubImage (const vpImage< Type > &I, const vpRect &rect, vpImage< Type > &S)

Detailed Description

Various image tools; sub-image extraction, modification of the look up table, binarisation...

Definition at line 78 of file vpImageTools.h.

Member Enumeration Documentation

◆ vpImageInterpolationType

enum vpImageTools::vpImageInterpolationType

Enumerator
INTERPOLATION_NEAREST	Nearest neighbor interpolation.
INTERPOLATION_LINEAR	Bi-linear interpolation (optimized by SIMD lib if enabled).
INTERPOLATION_CUBIC	Bi-cubic interpolation.
INTERPOLATION_AREA	Area interpolation (optimized by SIMD lib if enabled).

Definition at line 81 of file vpImageTools.h.

Member Function Documentation

◆ binarise() [1/2]

template<class Type >

void vpImageTools::binarise	(	vpImage< Type > &	I,
		Type	threshold1,
		Type	threshold2,
		Type	value1,
		Type	value2,
		Type	value3,
		bool	useLUT = `true`
	)

inlinestatic

Binarise an image.

Pixels whose values are less than threshold1 are set to value1
Pixels whose values are greater then or equal to threshold1 and less then or equal to threshold2 are set to value2
Pixels whose values are greater than threshold2 are set to value3

Examples:: testConnectedComponents.cpp, testContours.cpp, testFloodFill.cpp, testImageBinarise.cpp, and tutorial-ibvs-4pts-ogre-tracking.cpp.

Definition at line 459 of file vpImageTools.h.

References vpImage< Type >::bitmap, vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

Referenced by vp::autoThreshold().

◆ binarise() [2/2]

template<>

void vpImageTools::binarise	(	vpImage< unsigned char > &	I,
		unsigned char	threshold1,
		unsigned char	threshold2,
		unsigned char	value1,
		unsigned char	value2,
		unsigned char	value3,
		bool	useLUT
	)

inline

Binarise an image.

Pixels whose values are less than threshold1 are set to value1
Pixels whose values are greater then or equal to threshold1 and less then or equal to threshold2 are set to value2
Pixels whose values are greater than threshold2 are set to value3

Definition at line 491 of file vpImageTools.h.

References vpImage< Type >::bitmap, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::performLut().

◆ changeLUT()

void vpImageTools::changeLUT	(	vpImage< unsigned char > &	I,
		unsigned char	A,
		unsigned char	A_star,
		unsigned char	B,
		unsigned char	B_star
	)

static

Change the look up table (LUT) of an image. Considering pixel gray level values $ l $ in the range $[A, B]$ , this method allows to rescale these values in $[A^*, B^*]$ by linear interpolation:

$\left\{ \begin{array}{ll} l \in ]-\infty, A] \mbox{, } & l = A^* \\ l \in [B, \infty[ \mbox{, } & l = B^* \\ l \in ]A, B[ \mbox{, } & l = A^* + (l-A) * \frac{B^*-A^*}{B-A} \end{array} \right.$

Parameters

I	: Image to process.
A	: Low gray level value of the range to consider.
A_star	: New gray level value to attribute to pixel who's value was A
B	: Height gray level value of the range to consider.
B_star	: New gray level value to attribute to pixel who's value was B

Returns: The modified image.

Exceptions

vpImageException::incorrectInitializationError If $B \leq A$ .

As shown in the example below, this method can be used to binarize an image. For an unsigned char image (in the range 0-255), thresholding this image at level 127 can be done by:

#include <visp3/core/vpImage.h>
#include <visp3/core/vpImageTools.h>
#include <visp3/io/vpImageIo.h>
int main()
{
  vpImage<unsigned char> I;
#ifdef _WIN32
  std::string filename("C:/temp/ViSP-images/Klimt/Klimt.ppm");
#else
  std::string filename("/local/soft/ViSP/ViSP-images/Klimt/Klimt.ppm");
#endif
  // Read an image from the disk
  vpImageIo::read(I, filename);
  // Binarize image I:
  // - gray level values less than or equal to 127 are set to 0,
  // - gray level values greater than 128 are set to 255
  vpImageTools::changeLUT(I, 127, 0, 128, 255);
  vpImageIo::write(I, "Klimt.pgm"); // Write the image in a PGM P5 image file format
}

Definition at line 101 of file vpImageTools.cpp.

References vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpImageException::incorrectInitializationError, and vpERROR_TRACE.

◆ columnMean()

void vpImageTools::columnMean	(	const vpImage< double > &	I,
		vpRowVector &	V
	)

static

Compute the column-wise mean intensities.

Parameters

I	: The image.
V	: The result vector.

Definition at line 515 of file vpImageTools.cpp.

References vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpRowVector::resize().

◆ createSubImage() [1/4]

template<class Type >

static vp_deprecated void vpImageTools::createSubImage	(	const vpImage< Type > &	I,
		unsigned int	i_sub,
		unsigned int	j_sub,
		unsigned int	nrow_sub,
		unsigned int	ncol_sub,
		vpImage< Type > &	S
	)

static

◆ createSubImage() [2/4]

template<class Type >

static vp_deprecated void vpImageTools::createSubImage	(	const vpImage< Type > &	I,
		const vpRect &	rect,
		vpImage< Type > &	S
	)

static

◆ createSubImage() [3/4]

template<class Type >

void vpImageTools::createSubImage	(	const vpImage< Type > &	I,
		unsigned int	roi_top,
		unsigned int	roi_left,
		unsigned int	roi_height,
		unsigned int	roi_width,
		vpImage< Type > &	crop
	)

Crop a region of interest (ROI) in an image.

Deprecated:: This fonction is deprecated. You should rather use crop(const vpImage<Type> &, unsigned int, unsigned int, unsigned int, unsigned int, vpImage<Type> &).

Parameters

I	: Input image from which a sub image will be extracted.
roi_top	: ROI vertical position of the upper/left corner in the input image.
roi_left	: ROI horizontal position of the upper/left corner in the input image.
roi_height	: Cropped image height corresponding to the ROI height.
roi_width	: Cropped image width corresponding to the ROI height.
crop	: Cropped image.

See also: crop(const vpImage<Type> &, unsigned int, unsigned int, unsigned int, unsigned int, vpImage<Type> &)

Definition at line 254 of file vpImageTools.h.

References crop().

◆ createSubImage() [4/4]

template<class Type >

void vpImageTools::createSubImage	(	const vpImage< Type > &	I,
		const vpRect &	roi,
		vpImage< Type > &	crop
	)

Crop an image region of interest.

Deprecated:: This fonction is deprecated. You should rather use crop(const vpImage<Type> &, const vpRect &, vpImage<Type> &).

Parameters

I	: Input image from which a sub image will be extracted.
roi	: Region of interest in image I corresponding to the cropped part of the image.
crop	: Cropped image.

See also: crop(const vpImage<Type> &, const vpRect &, vpImage<Type> &)

Definition at line 275 of file vpImageTools.h.

References crop().

◆ crop() [1/4]

template<class Type >

void vpImageTools::crop	(	const vpImage< Type > &	I,
		double	roi_top,
		double	roi_left,
		unsigned int	roi_height,
		unsigned int	roi_width,
		vpImage< Type > &	crop,
		unsigned int	v_scale = `1`,
		unsigned int	h_scale = `1`
	)

static

Crop a region of interest (ROI) in an image. The ROI coordinates and dimension are defined in the original image.

Setting v_scale and h_scale to values different from 1 allows also to subsample the cropped image.

Parameters

I	: Input image from which a sub image will be extracted.
roi_top	: ROI vertical position of the upper/left corner in the input image.
roi_left	: ROI horizontal position of the upper/left corner in the input image.
roi_height	: Cropped image height corresponding to the ROI height.
roi_width	: Cropped image width corresponding to the ROI height.
crop	: Cropped image.
v_scale	[in] : Vertical subsampling factor applied to the ROI.
h_scale	[in] : Horizontal subsampling factor applied to the ROI.

See also: crop(const vpImage<Type> &, const vpRect &, vpImage<Type> &)

Examples:: testCrop.cpp, testCropAdvanced.cpp, testImageNormalizedCorrelation.cpp, and testImageTemplateMatching.cpp.

Definition at line 305 of file vpImageTools.h.

References vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

Referenced by vpV4l2Grabber::acquire(), createSubImage(), crop(), vpDisplayGTK::displayImageROI(), vpMeNurbs::seekExtremitiesCanny(), and templateMatching().

◆ crop() [2/4]

template<class Type >

void vpImageTools::crop	(	const vpImage< Type > &	I,
		const vpImagePoint &	topLeft,
		unsigned int	roi_height,
		unsigned int	roi_width,
		vpImage< Type > &	crop,
		unsigned int	v_scale = `1`,
		unsigned int	h_scale = `1`
	)

static

Crop a region of interest (ROI) in an image. The ROI coordinates and dimension are defined in the original image.

Setting v_scale and h_scale to values different from 1 allows also to subsample the cropped image.

Parameters

I	: Input image from which a sub image will be extracted.
topLeft	: ROI position of the upper/left corner in the input image.
roi_height	: Cropped image height corresponding to the ROI height.
roi_width	: Cropped image width corresponding to the ROI height.
crop	: Cropped image.
v_scale	[in] : Vertical subsampling factor applied to the ROI.
h_scale	[in] : Horizontal subsampling factor applied to the ROI.

See also: crop(const vpImage<Type> &, const vpRect &, vpImage<Type> &)

Definition at line 360 of file vpImageTools.h.

References crop(), vpImagePoint::get_i(), and vpImagePoint::get_j().

◆ crop() [3/4]

template<class Type >

void vpImageTools::crop	(	const vpImage< Type > &	I,
		const vpRect &	roi,
		vpImage< Type > &	crop,
		unsigned int	v_scale = `1`,
		unsigned int	h_scale = `1`
	)

static

Crop a region of interest (ROI) in an image. The ROI coordinates and dimension are defined in the original image.

Setting v_scale and h_scale to values different from 1 allows also to subsample the cropped image.

Parameters

I	: Input image from which a sub image will be extracted.
roi	: Region of interest in image I corresponding to the cropped part of the image.
crop	: Cropped image.
v_scale	[in] : Vertical subsampling factor applied to the ROI.
h_scale	[in] : Horizontal subsampling factor applied to the ROI.

Definition at line 383 of file vpImageTools.h.

References crop(), vpRect::getHeight(), vpRect::getLeft(), vpRect::getTop(), and vpRect::getWidth().

◆ crop() [4/4]

template<class Type >

void vpImageTools::crop	(	const unsigned char *	bitmap,
		unsigned int	width,
		unsigned int	height,
		const vpRect &	roi,
		vpImage< Type > &	crop,
		unsigned int	v_scale = `1`,
		unsigned int	h_scale = `1`
	)

static

Crop a region of interest (ROI) in an image. The ROI coordinates and dimension are defined in the original image.

Setting v_scale and h_scale to values different from 1 allows also to subsample the cropped image.

Parameters

bitmap	: Pointer to the input image from which a sub image will be extracted.
width,height	: Size of the input image.
roi	: Region of interest corresponding to the cropped part of the image.
crop	: Cropped image.
v_scale	[in] : Vertical subsampling factor applied to the ROI.
h_scale	[in] : Horizontal subsampling factor applied to the ROI.

Definition at line 408 of file vpImageTools.h.

References vpRect::getHeight(), vpRect::getLeft(), vpRect::getTop(), vpRect::getWidth(), and vpImage< Type >::resize().

◆ extract() [1/2]

void vpImageTools::extract	(	const vpImage< unsigned char > &	Src,
		vpImage< unsigned char > &	Dst,
		const vpRectOriented &	r
	)

static

Extract a rectangular region from an image.

Parameters

Src	: The source image.
Dst	: The resulting image.
r	: The rectangle area.

Definition at line 585 of file vpImageTools.cpp.

References vpImagePoint::get_i(), vpImagePoint::get_j(), vpRectOriented::getHeight(), vpRectOriented::getOrientation(), vpRectOriented::getTopLeft(), vpRectOriented::getWidth(), interpolate(), INTERPOLATION_LINEAR, vpImage< Type >::resize(), and vpMath::round().

◆ extract() [2/2]

void vpImageTools::extract	(	const vpImage< unsigned char > &	Src,
		vpImage< double > &	Dst,
		const vpRectOriented &	r
	)

static

Extract a rectangular region from an image.

Parameters

Src	: The source image.
Dst	: The resulting image.
r	: The rectangle area.

Definition at line 608 of file vpImageTools.cpp.

References vpImagePoint::get_i(), vpImagePoint::get_j(), vpRectOriented::getHeight(), vpRectOriented::getOrientation(), vpRectOriented::getTopLeft(), vpRectOriented::getWidth(), interpolate(), INTERPOLATION_LINEAR, vpImage< Type >::resize(), and vpMath::round().

◆ flip() [1/2]

template<class Type >

void vpImageTools::flip	(	const vpImage< Type > &	I,
		vpImage< Type > &	newI
	)

static

Flip vertically the input image and give the result in the output image.

Parameters

I	: Input image to flip.
newI	: Output image which is the flipped input image.

Definition at line 830 of file vpImageTools.h.

References vpImage< Type >::bitmap, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ flip() [2/2]

template<class Type >

void vpImageTools::flip ( vpImage< Type > & I )

static

Flip vertically the input image.

Parameters

I	: Input image which is flipped and modified in output.

The following example shows how to use this function:

#include <visp3/core/vpImage.h>
#include <visp3/core/vpImageTools.h>
#include <visp3/io/vpImageIo.h>
int main()
{
  vpImage<vpRGBa> I;
#ifdef _WIN32
  std::string filename("C:/temp/ViSP-images/Klimt/Klimt.ppm");
#else
  std::string filename("/local/soft/ViSP/ViSP-images/Klimt/Klimt.ppm");
#endif
  // Read an image from the disk
  vpImageIo::read(I, filename);
  // Flip the image
  vpImageTools::flip(I);
  // Write the image in a PGM P5 image file format
  vpImageIo::write(I, "Klimt-flip.ppm");
}

Definition at line 871 of file vpImageTools.h.

References vpImage< Type >::bitmap, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpImage< Type >::resize(), and vpMath::round().

◆ imageAdd()

void vpImageTools::imageAdd	(	const vpImage< unsigned char > &	I1,
		const vpImage< unsigned char > &	I2,
		vpImage< unsigned char > &	Ires,
		bool	saturate = `false`
	)

static

Compute the image addition: $ Ires = I1 + I2 $ .

Parameters

I1	: The first image.
I2	: The second image.
Ires	:
saturate	: If true, saturate the result to [0 ; 255] using vpMath::saturate, otherwise overflow may occur.

Note: The simd lib is used to accelerate processing on x86 and ARM architecture.

Warning: This function does not work in-place (Ires object must be different from I1 and I2).

Examples:: perfImageAddSub.cpp, and testImageAddSub.cpp.

Definition at line 282 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

Referenced by vp::fillHoles().

◆ imageDifference() [1/2]

void vpImageTools::imageDifference	(	const vpImage< unsigned char > &	I1,
		const vpImage< unsigned char > &	I2,
		vpImage< unsigned char > &	Idiff
	)

static

Compute the signed difference between the two images I1 and I2 for visualization purpose: Idiff = I1-I2

pixels with a null difference are set to 128.
A negative difference implies a pixel value < 128
A positive difference implies a pixel value > 128

Parameters

I1	: The first image.
I2	: The second image.
Idiff	: The result of the difference.

Examples:: photometricVisualServoing.cpp, photometricVisualServoingWithoutVpServo.cpp, testImageDifference.cpp, and testUndistortImage.cpp.

Definition at line 138 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getSize(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ imageDifference() [2/2]

void vpImageTools::imageDifference	(	const vpImage< vpRGBa > &	I1,
		const vpImage< vpRGBa > &	I2,
		vpImage< vpRGBa > &	Idiff
	)

static

Compute the signed difference between the two images I1 and I2 RGB components for visualization purpose: Idiff = I1-I2. The fourth component named A is not compared. It is set to 0 in the resulting difference image.

pixels with a null difference are set to R=128, G=128, B=128.
A negative difference implies a pixel R, G, B value < 128
A positive difference implies a pixel R, G, B value > 128

Parameters

I1	: The first image.
I2	: The second image.
Idiff	: The result of the difference between RGB components.

Definition at line 165 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getSize(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ imageDifferenceAbsolute() [1/3]

void vpImageTools::imageDifferenceAbsolute	(	const vpImage< unsigned char > &	I1,
		const vpImage< unsigned char > &	I2,
		vpImage< unsigned char > &	Idiff
	)

static

Compute the difference between the two images I1 and I2

Warning: : This is NOT for visualization If you want to visualize difference images during servo, please use vpImageTools::imageDifference(..,..,..) function.

Parameters

I1	: The first image.
I2	: The second image.
Idiff	: The result of the difference.

Examples:: testGaussianFilter.cpp, and testUndistortImage.cpp.

Definition at line 191 of file vpImageTools.cpp.

References vpMath::abs(), vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ imageDifferenceAbsolute() [2/3]

void vpImageTools::imageDifferenceAbsolute	(	const vpImage< double > &	I1,
		const vpImage< double > &	I2,
		vpImage< double > &	Idiff
	)

static

Compute the difference between the two images I1 and I2.

Parameters

I1	: The first image.
I2	: The second image.
Idiff	: The result of the difference.

Definition at line 216 of file vpImageTools.cpp.

References vpMath::abs(), vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ imageDifferenceAbsolute() [3/3]

void vpImageTools::imageDifferenceAbsolute	(	const vpImage< vpRGBa > &	I1,
		const vpImage< vpRGBa > &	I2,
		vpImage< vpRGBa > &	Idiff
	)

static

Compute the difference between the two images I1 and I2 RGB components. The fourth component named A is not compared. It is set to 0 in the resulting difference image.

Warning: : This is NOT for visualization. If you want to visualize difference images during servo, please use vpImageTools::imageDifference(..,..,..) function.

Parameters

I1	: The first image.
I2	: The second image.
Idiff	: The result of the difference between RGB components.

Definition at line 245 of file vpImageTools.cpp.

References vpRGBa::A, vpMath::abs(), vpRGBa::B, vpImage< Type >::bitmap, vpException::dimensionError, vpRGBa::G, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpRGBa::R, and vpImage< Type >::resize().

◆ imageSubtract()

void vpImageTools::imageSubtract	(	const vpImage< unsigned char > &	I1,
		const vpImage< unsigned char > &	I2,
		vpImage< unsigned char > &	Ires,
		bool	saturate = `false`
	)

static

Compute the image addition: $ Ires = I1 - I2 $ .

Parameters

I1	: The first image.
I2	: The second image.
Ires	:
saturate	: If true, saturate the result to [0 ; 255] using vpMath::saturate, otherwise overflow may occur.

Note: The simd lib is used to accelerate processing on x86 and ARM architecture.

Warning: This function does not work in-place (Ires object must be different from I1 and I2).

Examples:: perfImageAddSub.cpp, and testImageAddSub.cpp.

Definition at line 314 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

Referenced by vp::fillHoles().

◆ initUndistortMap()

void vpImageTools::initUndistortMap	(	const vpCameraParameters &	cam,
		unsigned int	width,
		unsigned int	height,
		vpArray2D< int > &	mapU,
		vpArray2D< int > &	mapV,
		vpArray2D< float > &	mapDu,
		vpArray2D< float > &	mapDv
	)

static

Compute the undistortion transformation map.

Parameters

cam	: Camera intrinsic parameters with distortion coefficients.
width	: Image width.
height	: Image height.
mapU	: 2D array that contains at each coordinate the u-coordinate in the distorted image.
mapV	: 2D array that contains at each coordinate the v-coordinate in the distorted image.
mapDu	: 2D array that contains at each coordinate the $\Delta u$ for the interpolation.
mapDv	: 2D array that contains at each coordinate the $\Delta v$ for the interpolation.

Examples:: testRealSense2_T265_undistort.cpp, testUndistortImage.cpp, and tutorial-apriltag-detector-live-T265-realsense.cpp.

Definition at line 344 of file vpImageTools.cpp.

References vpCameraParameters::get_kud(), vpCameraParameters::get_projModel(), vpCameraParameters::get_px(), vpCameraParameters::get_py(), vpCameraParameters::get_u0(), vpCameraParameters::get_v0(), vpCameraParameters::getKannalaBrandtDistortionCoefficients(), vpCameraParameters::ProjWithKannalaBrandtDistortion, vpArray2D< Type >::resize(), and vpMath::sqr().

◆ integralImage()

void vpImageTools::integralImage	(	const vpImage< unsigned char > &	I,
		vpImage< double > &	II,
		vpImage< double > &	IIsq
	)

static

Compute the integral images:

$II(u,v)=\sum_{u^{'}\leq u, v^{'}\leq v}I(u,v)$

$IIsq(u,v)=\sum_{u^{'}\leq u, v^{'}\leq v}I(u,v)^2$ .

Parameters

I	: Input image.
II	: Integral image II.
IIsq	: Integral image IIsq.

Examples:: testImageTemplateMatching.cpp.

Definition at line 464 of file vpImageTools.cpp.

References vpImage< Type >::getHeight(), vpImage< Type >::getSize(), vpImage< Type >::getWidth(), vpImage< Type >::resize(), and vpMath::sqr().

Referenced by templateMatching().

◆ interpolate()

double vpImageTools::interpolate	(	const vpImage< unsigned char > &	I,
		const vpImagePoint &	point,
		const vpImageInterpolationType &	method = `INTERPOLATION_NEAREST`
	)

static

Get the interpolated value at a given location.

Parameters

I	: The image to perform intepolation in.
point	: The image point.
method	: The interpolation method (only interpolation with vpImageTools::INTERPOLATION_NEAREST and vpImageTools::INTERPOLATION_LINEAR are implemented).

Definition at line 546 of file vpImageTools.cpp.

References vpImagePoint::get_i(), vpImagePoint::get_j(), INTERPOLATION_CUBIC, INTERPOLATION_LINEAR, INTERPOLATION_NEAREST, vpException::notImplementedError, and vpMath::round().

Referenced by extract().

◆ normalize()

void vpImageTools::normalize ( vpImage< double > & I )

static

Normalize the image intensities.

Parameters

I	: The image to normalize.

Definition at line 531 of file vpImageTools.cpp.

References vpImage< Type >::getHeight(), vpImage< Type >::getSum(), and vpImage< Type >::getWidth().

◆ normalizedCorrelation()

double vpImageTools::normalizedCorrelation	(	const vpImage< double > &	I1,
		const vpImage< double > &	I2,
		bool	useOptimized = `true`
	)

static

Compute a correlation between 2 images.

Parameters

I1	: The first image.
I2	: The second image.
useOptimized	: Use SSE if true and available.

Examples:: testImageNormalizedCorrelation.cpp.

Definition at line 489 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpException::dimensionError, vpImage< Type >::getHeight(), vpImage< Type >::getMeanValue(), vpImage< Type >::getSize(), and vpImage< Type >::getWidth().

Referenced by templateMatching().

◆ remap() [1/2]

void vpImageTools::remap	(	const vpImage< unsigned char > &	I,
		const vpArray2D< int > &	mapU,
		const vpArray2D< int > &	mapV,
		const vpArray2D< float > &	mapDu,
		const vpArray2D< float > &	mapDv,
		vpImage< unsigned char > &	Iundist
	)

static

Apply the transformation map to the image.

Parameters

I	: Input grayscale image.
mapU	: Map that contains at each destination coordinate the u-coordinate in the source image.
mapV	: Map that contains at each destination coordinate the v-coordinate in the source image.
mapDu	: Map that contains at each destination coordinate the $\Delta u$ for the interpolation.
mapDv	: Map that contains at each destination coordinate the $\Delta v$ for the interpolation.
Iundist	: Output transformed grayscale image.

Examples:: testUndistortImage.cpp.

Definition at line 783 of file vpImageTools.cpp.

References vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), and vpImage< Type >::resize().

◆ remap() [2/2]

void vpImageTools::remap	(	const vpImage< vpRGBa > &	I,
		const vpArray2D< int > &	mapU,
		const vpArray2D< int > &	mapV,
		const vpArray2D< float > &	mapDu,
		const vpArray2D< float > &	mapDv,
		vpImage< vpRGBa > &	Iundist
	)

static

Apply the transformation map to the image.

Parameters

I	: Input color image.
mapU	: Map that contains at each destination coordinate the u-coordinate in the source image.
mapV	: Map that contains at each destination coordinate the v-coordinate in the source image.
mapDu	: Map that contains at each destination coordinate the $\Delta u$ for the interpolation.
mapDv	: Map that contains at each destination coordinate the $\Delta v$ for the interpolation.
Iundist	: Output transformed color image.

Definition at line 826 of file vpImageTools.cpp.

References vpMath::abs(), vpImage< Type >::bitmap, vpArray2D< Type >::data, vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), INTERPOLATION_LINEAR, and vpImage< Type >::resize().

◆ resize() [1/4]

template<class Type >

void vpImageTools::resize	(	const vpImage< Type > &	I,
		vpImage< Type > &	Ires,
		unsigned int	width,
		unsigned int	height,
		const vpImageInterpolationType &	method = `INTERPOLATION_NEAREST`,
		unsigned int	nThreads = `0`
	)

static

Resize the image using one interpolation method (by default it uses the nearest neighbor interpolation).

Parameters

I	: Input image.
Ires	: Output image resized to width, height.
width	: Resized width.
height	: Resized height.
method	: Interpolation method.
nThreads	: Number of threads to use if OpenMP is available (zero will let OpenMP uses the optimal number of threads).

Warning: The input I and output Ires images must be different objects.

Note

The SIMD lib is used to accelerate processing on x86 and ARM architecture for:

unsigned char and vpRGBa image types
and only with INTERPOLATION_AREA and INTERPOLATION_LINEAR methods

Examples:: testImageResize.cpp, and testUndistortImage.cpp.

Definition at line 1060 of file vpImageTools.h.

References vpImage< Type >::resize().

◆ resize() [2/4]

template<class Type >

void vpImageTools::resize	(	const vpImage< Type > &	I,
		vpImage< Type > &	Ires,
		const vpImageInterpolationType &	method = `INTERPOLATION_NEAREST`,
		unsigned int	nThreads = `0`
	)

static

Resize the image using one interpolation method (by default it uses the nearest neighbor interpolation).

Parameters

I	: Input image.
Ires	: Output image resized (you have to init the image Ires at the desired size).
method	: Interpolation method.
nThreads	: Number of threads to use if OpenMP is available (zero will let OpenMP uses the optimal number of threads).

Warning: The input I and output Ires images must be different objects.

Note

The SIMD lib is used to accelerate processing on x86 and ARM architecture for:

unsigned char and vpRGBa image types
and only with INTERPOLATION_AREA and INTERPOLATION_LINEAR methods

Definition at line 1087 of file vpImageTools.h.

References vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

◆ resize() [3/4]

template<>

void vpImageTools::resize	(	const vpImage< unsigned char > &	I,
		vpImage< unsigned char > &	Ires,
		const vpImageInterpolationType &	method,
		unsigned	int
	)

inline

Definition at line 1136 of file vpImageTools.h.

References vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

◆ resize() [4/4]

template<>

void vpImageTools::resize	(	const vpImage< vpRGBa > &	I,
		vpImage< vpRGBa > &	Ires,
		const vpImageInterpolationType &	method,
		unsigned	int
	)

inline

Definition at line 1182 of file vpImageTools.h.

References vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

◆ resizeBicubic()

template<>

void vpImageTools::resizeBicubic	(	const vpImage< vpRGBa > &	I,
		vpImage< vpRGBa > &	Ires,
		unsigned int	i,
		unsigned int	j,
		float	u,
		float	v,
		float	xFrac,
		float	yFrac
	)

inline

Definition at line 934 of file vpImageTools.h.

References vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

◆ resizeBilinear()

template<>

void vpImageTools::resizeBilinear	(	const vpImage< vpRGBa > &	I,
		vpImage< vpRGBa > &	Ires,
		unsigned int	i,
		unsigned int	j,
		float	u,
		float	v,
		float	xFrac,
		float	yFrac
	)

inline

Definition at line 1008 of file vpImageTools.h.

References vpImage< Type >::getHeight(), and vpImage< Type >::getWidth().

◆ templateMatching()

void vpImageTools::templateMatching	(	const vpImage< unsigned char > &	I,
		const vpImage< unsigned char > &	I_tpl,
		vpImage< double > &	I_score,
		unsigned int	step_u,
		unsigned int	step_v,
		bool	useOptimized = `true`
	)

static

Match a template image into another image using zero-mean normalized cross-correlation:

$\frac{\sum_{u^{'},v^{'}} (I(u+u^{'},v+v^{'})-\bar{I}_{u^{'},v^{'}}) (T(u^{'},v^{'})-\bar{T}_{u^{'},v^{'}})}{\sqrt{\sum_{u^{'},v^{'}} (I(u+u^{'},v+v^{'})-\bar{I}_{u^{'},v^{'}})^2 \sum_{u^{'},v^{'}}(T(u^{'},v^{'})-\bar{T}_{u^{'},v^{'}})^2}}$

Parameters

I	: Input image.
I_tpl	: Template image.
I_score	: Output template matching score.
step_u	: Step in u-direction to speed-up the computation.
step_v	: Step in v-direction to speed-up the computation.
useOptimized	: Use optimized version (SSE, OpenMP, integral images, ...) if true and available.

Examples:: testImageTemplateMatching.cpp.

Definition at line 638 of file vpImageTools.cpp.

References vpImage< Type >::bitmap, vpImageConvert::convert(), crop(), vpImage< Type >::getHeight(), vpImage< Type >::getSize(), vpImage< Type >::getWidth(), integralImage(), normalizedCorrelation(), vpImage< Type >::resize(), and vpMath::sqr().

◆ undistort() [1/2]

template<class Type >

void vpImageTools::undistort	(	const vpImage< Type > &	I,
		const vpCameraParameters &	cam,
		vpImage< Type > &	undistI,
		unsigned int	nThreads = `2`
	)

static

Undistort an image

Parameters

I	: Input image to undistort.
cam	: Parameters of the camera causing distortion.
undistI	: Undistorted output image. The size of this image will be the same than the input image I. If the distortion parameter $k_{ud}$ is null, meaning that `cam.get_kud() == 0`, undistI is just a copy of I.
nThreads	: Number of threads to use if pthreads library is available.

Warning: This function works only with Types authorizing "+,-, multiplication by a scalar" operators.

Since this function is time consuming, if you want to undistort multiple images, you should rather call initUndistortMap() once and then remap() to undistort the images. This will be less time consuming.

See also: initUndistortMap(), remap()

Examples:: testRealSense2_T265_undistort.cpp, testUndistortImage.cpp, tutorial-apriltag-detector-live-T265-realsense.cpp, and tutorial-undistort.cpp.

Definition at line 645 of file vpImageTools.h.

References vpImage< Type >::bitmap, vpCameraParameters::get_kud(), vpCameraParameters::get_px(), vpCameraParameters::get_py(), vpCameraParameters::get_u0(), vpCameraParameters::get_v0(), vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpImage< Type >::resize(), and vpMath::sqr().

◆ undistort() [2/2]

template<class Type >

void vpImageTools::undistort	(	const vpImage< Type > &	I,
		vpArray2D< int >	mapU,
		vpArray2D< int >	mapV,
		vpArray2D< float >	mapDu,
		vpArray2D< float >	mapDv,
		vpImage< Type > &	newI
	)

static

Undistort an image.

Parameters

I	: Input image to undistort.
mapU	: Map that contains at each destination coordinate the u-coordinate in the source image.
mapV	: Map that contains at each destination coordinate the v-coordinate in the source image.
mapDu	: Map that contains at each destination coordinate the $\Delta u$ for the interpolation.
mapDv	: Map that contains at each destination coordinate the $\Delta v$ for the interpolation.
newI	: Undistorted output image. The size of this image will be the same as the input image I.

Note: To undistort a fisheye image, you have to first call initUndistortMap() function to calculate maps and then call undistort() with input maps.

Definition at line 818 of file vpImageTools.h.

◆ warpImage()

template<class Type >

void vpImageTools::warpImage	(	const vpImage< Type > &	src,
		const vpMatrix &	T,
		vpImage< Type > &	dst,
		const vpImageInterpolationType &	interpolation = `INTERPOLATION_NEAREST`,
		bool	fixedPointArithmetic = `true`,
		bool	pixelCenter = `false`
	)

static

Apply a warping (affine or perspective) transformation to an image.

Parameters

src	: Input image.
T	: Transformation / warping matrix, a `2x3` matrix for an affine transformation or a `3x3` matrix for a perspective transformation (homography).
dst	: Output image, if empty it will be of the same size than src and zero-initialized.
interpolation	: Interpolation method (only INTERPOLATION_NEAREST and INTERPOLATION_LINEAR are accepted, if INTERPOLATION_CUBIC is passed, INTERPOLATION_NEAREST will be used instead).
fixedPointArithmetic	: If true and if `pixelCenter` is false, fixed-point arithmetic is used if possible. Otherwise (e.g. the input image is too big) it fallbacks to the default implementation.
pixelCenter	: If true, pixel coordinates are at (0.5, 0.5), otherwise at (0,0). Fixed-point arithmetic cannot be used with `pixelCenter` option.

Examples:: testImageWarp.cpp.

Definition at line 1242 of file vpImageTools.h.

References vpArray2D< Type >::getCols(), vpImage< Type >::getHeight(), vpArray2D< Type >::getRows(), vpImage< Type >::getSize(), vpImage< Type >::getWidth(), vpMatrix::inverseByLU(), vpMath::nul(), vpImage< Type >::resize(), and vpMath::round().

◆ warpLinear()

template<>

void vpImageTools::warpLinear	(	const vpImage< vpRGBa > &	src,
		const vpMatrix &	T,
		vpImage< vpRGBa > &	dst,
		bool	affine,
		bool	centerCorner,
		bool	fixedPoint
	)

inline

Definition at line 1579 of file vpImageTools.h.

References vpRGBa::B, vpRGBa::G, vpImage< Type >::getHeight(), vpArray2D< Type >::getRows(), vpImage< Type >::getWidth(), and vpRGBa::R.

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ vpImageInterpolationType

Member Function Documentation

◆ binarise() [1/2]

◆ binarise() [2/2]

◆ changeLUT()

◆ columnMean()

◆ createSubImage() [1/4]

◆ createSubImage() [2/4]

◆ createSubImage() [3/4]

◆ createSubImage() [4/4]

◆ crop() [1/4]

◆ crop() [2/4]

◆ crop() [3/4]

◆ crop() [4/4]

◆ extract() [1/2]

◆ extract() [2/2]

◆ flip() [1/2]

◆ flip() [2/2]

◆ imageAdd()

◆ imageDifference() [1/2]

◆ imageDifference() [2/2]

◆ imageDifferenceAbsolute() [1/3]

◆ imageDifferenceAbsolute() [2/3]

◆ imageDifferenceAbsolute() [3/3]

◆ imageSubtract()

◆ initUndistortMap()

◆ integralImage()

◆ interpolate()

◆ normalize()

◆ normalizedCorrelation()

◆ remap() [1/2]

◆ remap() [2/2]

◆ resize() [1/4]

◆ resize() [2/4]

◆ resize() [3/4]

◆ resize() [4/4]

◆ resizeBicubic()

◆ resizeBilinear()

◆ templateMatching()

◆ undistort() [1/2]

◆ undistort() [2/2]

◆ warpImage()

◆ warpLinear()