OpenCV  4.1.1-pre
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cv::StereoSGBM Class Referenceabstract

The class implements the modified H. More...

#include <opencv2/calib3d.hpp>

Inheritance diagram for cv::StereoSGBM:
Collaboration diagram for cv::StereoSGBM:

Public Types

enum  {
  DISP_SHIFT = 4,
  DISP_SCALE = (1 << DISP_SHIFT)
}
 
enum  {
  MODE_SGBM = 0,
  MODE_HH = 1,
  MODE_SGBM_3WAY = 2,
  MODE_HH4 = 3
}
 

Public Member Functions

virtual void clear ()
 Clears the algorithm state. More...
 
virtual void compute (InputArray left, InputArray right, OutputArray disparity)=0
 Computes disparity map for the specified stereo pair. More...
 
virtual bool empty () const
 Returns true if the Algorithm is empty (e.g. More...
 
virtual int getBlockSize () const =0
 
virtual String getDefaultName () const
 Returns the algorithm string identifier. More...
 
virtual int getDisp12MaxDiff () const =0
 
virtual int getMinDisparity () const =0
 
virtual int getMode () const =0
 
virtual int getNumDisparities () const =0
 
virtual int getP1 () const =0
 
virtual int getP2 () const =0
 
virtual int getPreFilterCap () const =0
 
virtual int getSpeckleRange () const =0
 
virtual int getSpeckleWindowSize () const =0
 
virtual int getUniquenessRatio () const =0
 
virtual void read (const FileNode &fn)
 Reads algorithm parameters from a file storage. More...
 
virtual void save (const String &filename) const
 Saves the algorithm to a file. More...
 
virtual void setBlockSize (int blockSize)=0
 
virtual void setDisp12MaxDiff (int disp12MaxDiff)=0
 
virtual void setMinDisparity (int minDisparity)=0
 
virtual void setMode (int mode)=0
 
virtual void setNumDisparities (int numDisparities)=0
 
virtual void setP1 (int P1)=0
 
virtual void setP2 (int P2)=0
 
virtual void setPreFilterCap (int preFilterCap)=0
 
virtual void setSpeckleRange (int speckleRange)=0
 
virtual void setSpeckleWindowSize (int speckleWindowSize)=0
 
virtual void setUniquenessRatio (int uniquenessRatio)=0
 
virtual void write (FileStorage &fs) const
 Stores algorithm parameters in a file storage. More...
 
void write (const Ptr< FileStorage > &fs, const String &name=String()) const
 simplified API for language bindings This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. More...
 

Static Public Member Functions

static Ptr< StereoSGBMcreate (int minDisparity=0, int numDisparities=16, int blockSize=3, int P1=0, int P2=0, int disp12MaxDiff=0, int preFilterCap=0, int uniquenessRatio=0, int speckleWindowSize=0, int speckleRange=0, int mode=StereoSGBM::MODE_SGBM)
 Creates StereoSGBM object. More...
 
template<typename _Tp >
static Ptr< _Tp > load (const String &filename, const String &objname=String())
 Loads algorithm from the file. More...
 
template<typename _Tp >
static Ptr< _Tp > loadFromString (const String &strModel, const String &objname=String())
 Loads algorithm from a String. More...
 
template<typename _Tp >
static Ptr< _Tp > read (const FileNode &fn)
 Reads algorithm from the file node. More...
 

Protected Member Functions

void writeFormat (FileStorage &fs) const
 

Detailed Description

The class implements the modified H.

Hirschmuller algorithm [43] that differs from the original one as follows:

  • By default, the algorithm is single-pass, which means that you consider only 5 directions instead of 8. Set mode=StereoSGBM::MODE_HH in createStereoSGBM to run the full variant of the algorithm but beware that it may consume a lot of memory.
  • The algorithm matches blocks, not individual pixels. Though, setting blockSize=1 reduces the blocks to single pixels.
  • Mutual information cost function is not implemented. Instead, a simpler Birchfield-Tomasi sub-pixel metric from [7] is used. Though, the color images are supported as well.
  • Some pre- and post- processing steps from K. Konolige algorithm StereoBM are included, for example: pre-filtering (StereoBM::PREFILTER_XSOBEL type) and post-filtering (uniqueness check, quadratic interpolation and speckle filtering).
Note
  • (Python) An example illustrating the use of the StereoSGBM matching algorithm can be found at opencv_source_code/samples/python/stereo_match.py

Member Enumeration Documentation

◆ anonymous enum

anonymous enum
inherited
Enumerator
DISP_SHIFT 
DISP_SCALE 

◆ anonymous enum

anonymous enum
Enumerator
MODE_SGBM 
MODE_HH 
MODE_SGBM_3WAY 
MODE_HH4 

Member Function Documentation

◆ clear()

virtual void cv::Algorithm::clear ( )
inlinevirtualinherited

Clears the algorithm state.

Reimplemented in cv::FlannBasedMatcher, and cv::DescriptorMatcher.

◆ compute()

virtual void cv::StereoMatcher::compute ( InputArray  left,
InputArray  right,
OutputArray  disparity 
)
pure virtualinherited

Computes disparity map for the specified stereo pair.

Parameters
leftLeft 8-bit single-channel image.
rightRight image of the same size and the same type as the left one.
disparityOutput disparity map. It has the same size as the input images. Some algorithms, like StereoBM or StereoSGBM compute 16-bit fixed-point disparity map (where each disparity value has 4 fractional bits), whereas other algorithms output 32-bit floating-point disparity map.

◆ create()

static Ptr<StereoSGBM> cv::StereoSGBM::create ( int  minDisparity = 0,
int  numDisparities = 16,
int  blockSize = 3,
int  P1 = 0,
int  P2 = 0,
int  disp12MaxDiff = 0,
int  preFilterCap = 0,
int  uniquenessRatio = 0,
int  speckleWindowSize = 0,
int  speckleRange = 0,
int  mode = StereoSGBM::MODE_SGBM 
)
static

Creates StereoSGBM object.

Parameters
minDisparityMinimum possible disparity value. Normally, it is zero but sometimes rectification algorithms can shift images, so this parameter needs to be adjusted accordingly.
numDisparitiesMaximum disparity minus minimum disparity. The value is always greater than zero. In the current implementation, this parameter must be divisible by 16.
blockSizeMatched block size. It must be an odd number >=1 . Normally, it should be somewhere in the 3..11 range.
P1The first parameter controlling the disparity smoothness. See below.
P2The second parameter controlling the disparity smoothness. The larger the values are, the smoother the disparity is. P1 is the penalty on the disparity change by plus or minus 1 between neighbor pixels. P2 is the penalty on the disparity change by more than 1 between neighbor pixels. The algorithm requires P2 > P1 . See stereo_match.cpp sample where some reasonably good P1 and P2 values are shown (like 8*number_of_image_channels*SADWindowSize*SADWindowSize and 32*number_of_image_channels*SADWindowSize*SADWindowSize , respectively).
disp12MaxDiffMaximum allowed difference (in integer pixel units) in the left-right disparity check. Set it to a non-positive value to disable the check.
preFilterCapTruncation value for the prefiltered image pixels. The algorithm first computes x-derivative at each pixel and clips its value by [-preFilterCap, preFilterCap] interval. The result values are passed to the Birchfield-Tomasi pixel cost function.
uniquenessRatioMargin in percentage by which the best (minimum) computed cost function value should "win" the second best value to consider the found match correct. Normally, a value within the 5-15 range is good enough.
speckleWindowSizeMaximum size of smooth disparity regions to consider their noise speckles and invalidate. Set it to 0 to disable speckle filtering. Otherwise, set it somewhere in the 50-200 range.
speckleRangeMaximum disparity variation within each connected component. If you do speckle filtering, set the parameter to a positive value, it will be implicitly multiplied by 16. Normally, 1 or 2 is good enough.
modeSet it to StereoSGBM::MODE_HH to run the full-scale two-pass dynamic programming algorithm. It will consume O(W*H*numDisparities) bytes, which is large for 640x480 stereo and huge for HD-size pictures. By default, it is set to false .

The first constructor initializes StereoSGBM with all the default parameters. So, you only have to set StereoSGBM::numDisparities at minimum. The second constructor enables you to set each parameter to a custom value.

◆ empty()

virtual bool cv::Algorithm::empty ( ) const
inlinevirtualinherited

Returns true if the Algorithm is empty (e.g.

in the very beginning or after unsuccessful read

Reimplemented in cv::DescriptorMatcher, cv::ml::StatModel, cv::Feature2D, and cv::BaseCascadeClassifier.

◆ getBlockSize()

virtual int cv::StereoMatcher::getBlockSize ( ) const
pure virtualinherited

◆ getDefaultName()

virtual String cv::Algorithm::getDefaultName ( ) const
virtualinherited

Returns the algorithm string identifier.

This string is used as top level xml/yml node tag when the object is saved to a file or string.

Reimplemented in cv::AKAZE, cv::KAZE, cv::SimpleBlobDetector, cv::GFTTDetector, cv::AgastFeatureDetector, cv::FastFeatureDetector, cv::MSER, cv::ORB, cv::BRISK, and cv::Feature2D.

◆ getDisp12MaxDiff()

virtual int cv::StereoMatcher::getDisp12MaxDiff ( ) const
pure virtualinherited

◆ getMinDisparity()

virtual int cv::StereoMatcher::getMinDisparity ( ) const
pure virtualinherited

◆ getMode()

virtual int cv::StereoSGBM::getMode ( ) const
pure virtual

◆ getNumDisparities()

virtual int cv::StereoMatcher::getNumDisparities ( ) const
pure virtualinherited

◆ getP1()

virtual int cv::StereoSGBM::getP1 ( ) const
pure virtual

◆ getP2()

virtual int cv::StereoSGBM::getP2 ( ) const
pure virtual

◆ getPreFilterCap()

virtual int cv::StereoSGBM::getPreFilterCap ( ) const
pure virtual

◆ getSpeckleRange()

virtual int cv::StereoMatcher::getSpeckleRange ( ) const
pure virtualinherited

◆ getSpeckleWindowSize()

virtual int cv::StereoMatcher::getSpeckleWindowSize ( ) const
pure virtualinherited

◆ getUniquenessRatio()

virtual int cv::StereoSGBM::getUniquenessRatio ( ) const
pure virtual

◆ load()

template<typename _Tp >
static Ptr<_Tp> cv::Algorithm::load ( const String filename,
const String objname = String() 
)
inlinestaticinherited

Loads algorithm from the file.

Parameters
filenameName of the file to read.
objnameThe optional name of the node to read (if empty, the first top-level node will be used)

This is static template method of Algorithm. It's usage is following (in the case of SVM):

Ptr<SVM> svm = Algorithm::load<SVM>("my_svm_model.xml");

In order to make this method work, the derived class must overwrite Algorithm::read(const FileNode& fn).

References CV_Assert, cv::FileNode::empty(), cv::FileStorage::getFirstTopLevelNode(), cv::FileStorage::isOpened(), and cv::FileStorage::READ.

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◆ loadFromString()

template<typename _Tp >
static Ptr<_Tp> cv::Algorithm::loadFromString ( const String strModel,
const String objname = String() 
)
inlinestaticinherited

Loads algorithm from a String.

Parameters
strModelThe string variable containing the model you want to load.
objnameThe optional name of the node to read (if empty, the first top-level node will be used)

This is static template method of Algorithm. It's usage is following (in the case of SVM):

Ptr<SVM> svm = Algorithm::loadFromString<SVM>(myStringModel);

References CV_WRAP, cv::FileNode::empty(), cv::FileStorage::getFirstTopLevelNode(), cv::FileStorage::MEMORY, and cv::FileStorage::READ.

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◆ read() [1/2]

virtual void cv::Algorithm::read ( const FileNode fn)
inlinevirtualinherited

Reads algorithm parameters from a file storage.

Reimplemented in cv::FlannBasedMatcher, cv::DescriptorMatcher, and cv::Feature2D.

◆ read() [2/2]

template<typename _Tp >
static Ptr<_Tp> cv::Algorithm::read ( const FileNode fn)
inlinestaticinherited

Reads algorithm from the file node.

This is static template method of Algorithm. It's usage is following (in the case of SVM):

cv::FileStorage fsRead("example.xml", FileStorage::READ);
Ptr<SVM> svm = Algorithm::read<SVM>(fsRead.root());

In order to make this method work, the derived class must overwrite Algorithm::read(const FileNode& fn) and also have static create() method without parameters (or with all the optional parameters)

◆ save()

virtual void cv::Algorithm::save ( const String filename) const
virtualinherited

Saves the algorithm to a file.

In order to make this method work, the derived class must implement Algorithm::write(FileStorage& fs).

◆ setBlockSize()

virtual void cv::StereoMatcher::setBlockSize ( int  blockSize)
pure virtualinherited

◆ setDisp12MaxDiff()

virtual void cv::StereoMatcher::setDisp12MaxDiff ( int  disp12MaxDiff)
pure virtualinherited

◆ setMinDisparity()

virtual void cv::StereoMatcher::setMinDisparity ( int  minDisparity)
pure virtualinherited

◆ setMode()

virtual void cv::StereoSGBM::setMode ( int  mode)
pure virtual

◆ setNumDisparities()

virtual void cv::StereoMatcher::setNumDisparities ( int  numDisparities)
pure virtualinherited

◆ setP1()

virtual void cv::StereoSGBM::setP1 ( int  P1)
pure virtual

◆ setP2()

virtual void cv::StereoSGBM::setP2 ( int  P2)
pure virtual

◆ setPreFilterCap()

virtual void cv::StereoSGBM::setPreFilterCap ( int  preFilterCap)
pure virtual

◆ setSpeckleRange()

virtual void cv::StereoMatcher::setSpeckleRange ( int  speckleRange)
pure virtualinherited

◆ setSpeckleWindowSize()

virtual void cv::StereoMatcher::setSpeckleWindowSize ( int  speckleWindowSize)
pure virtualinherited

◆ setUniquenessRatio()

virtual void cv::StereoSGBM::setUniquenessRatio ( int  uniquenessRatio)
pure virtual

◆ write() [1/2]

virtual void cv::Algorithm::write ( FileStorage fs) const
inlinevirtualinherited

Stores algorithm parameters in a file storage.

Reimplemented in cv::FlannBasedMatcher, cv::DescriptorMatcher, and cv::Feature2D.

References CV_WRAP.

Referenced by cv::Feature2D::write(), and cv::DescriptorMatcher::write().

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◆ write() [2/2]

void cv::Algorithm::write ( const Ptr< FileStorage > &  fs,
const String name = String() 
) const
inherited

simplified API for language bindings This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

◆ writeFormat()

void cv::Algorithm::writeFormat ( FileStorage fs) const
protectedinherited

The documentation for this class was generated from the following file: