#include <vpImageTools.h>

Static Public Member Functions
template<class Type >
static 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 void	createSubImage (const vpImage< Type > &I, const vpRect &rect, vpImage< Type > &S)

template<class Type >
static void	binarise (vpImage< Type > &I, Type threshold1, Type threshold2, Type value1, Type value2, Type value3)

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

template<class Type >
static void	undistort (const vpImage< Type > &I, const vpCameraParameters &cam, vpImage< Type > &newI)

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

Detailed Description

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

Definition at line 79 of file vpImageTools.h.

Member Function Documentation

template<class Type >

void vpImageTools::binarise	(	vpImage< Type > &	I,
		Type	threshold1,
		Type	threshold2,
		Type	value1,
		Type	value2,
		Type	value3
	)

static

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:: tutorial-ibvs-4pts-ogre-tracking.cpp.

Definition at line 221 of file vpImageTools.h.

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

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 <visp/vpImageTools.h>
#include <visp/vpImage.h>
#include <visp/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 102 of file vpImageTools.cpp.

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

template<class Type >

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

Extract a sub part of an image

Parameters

I	: Input image from which a sub image will be extracted.
i_sub,j_sub	: coordinates of the upper left point of the sub image
nrow_sub,ncol_sub	: number of row, column of the sub image
S	: Sub-image.

Examples:: testCreateSubImage.cpp.

Definition at line 133 of file vpImageTools.h.

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

Referenced by vpKeyPointSurf::buildReference(), vpFernClassifier::buildReference(), vpDisplayOpenCV::displayImageROI(), vpDisplayGTK::displayImageROI(), vpPlanarObjectDetector::matchPoint(), vpKeyPointSurf::matchPoint(), vpFernClassifier::matchPoint(), and vpMeNurbs::seekExtremitiesCanny().

template<class Type >

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

static

Extract a sub part of an image

Parameters

I	: Input image from which a sub image will be extracted.
rect	: Rectangle area in the image I corresponding to the sub part of the image to extract.
S	: Sub-image.

Definition at line 171 of file vpImageTools.h.

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

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 533 of file vpImageTools.h.

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

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 <visp/vpImageTools.h>
#include <visp/vpImage.h>
#include <visp/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);
  vpImageIo::write(I, "Klimt-flip.ppm"); // Write the image in a PGM P5 image file format
}

Definition at line 582 of file vpImageTools.h.

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

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 issue : 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.

Definition at line 143 of file vpImageTools.cpp.

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

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.

Definition at line 177 of file vpImageTools.cpp.

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

template<class Type >

void vpImageTools::undistort	(	const vpImage< Type > &	I,
		const vpCameraParameters &	cam,
		vpImage< Type > &	undistI
	)

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 is null (see cam.get_kd_mp()), undistI is just a copy of I.

Warning

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

This function is time consuming :

On "Rhea"(Intel Core 2 Extreme X6800 2.93GHz, 2Go RAM) or "Charon"(Intel Xeon 3 GHz, 2Go RAM) : ~8 ms for a 640x480 image.

Examples:: testUndistortImage.cpp, and tutorial-undistort.cpp.

Definition at line 362 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().

Static Public Member Functions

Detailed Description

Member Function Documentation