Visual Servoing Platform  version 3.4.0
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vpImageTools Class Reference
core: Core module » Image manipulation

#include <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

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

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().

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().

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 $ A^*$ 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 $ B^*$ to attribute to pixel who's value was B
Returns
The modified image.
Exceptions
vpImageException::incorrectInitializationErrorIf $B \leq A$.

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.

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().

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

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().

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().

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().

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().

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().

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().

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().

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().

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 874 of file vpImageTools.h.

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

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: $ Ires = I1 + I2 $
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().

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().

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().

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().

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().

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().

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: $ Ires = I1 - I2 $
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().

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().

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().

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().

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().

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().

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().

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().

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 1067 of file vpImageTools.h.

References vpImage< Type >::resize().

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 1094 of file vpImageTools.h.

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

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

Definition at line 1143 of file vpImageTools.h.

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

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

Definition at line 1189 of file vpImageTools.h.

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

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 941 of file vpImageTools.h.

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

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 1015 of file vpImageTools.h.

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

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().

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().

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.

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 1249 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().

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

Definition at line 1586 of file vpImageTools.h.

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