Global Motion Estimation

Detailed Description

The video stabilization module contains a set of functions and classes for global motion estimation between point clouds or between images. In the last case features are extracted and matched internally. For the sake of convenience the motion estimation functions are wrapped into classes. Both the functions and the classes are available.

Classes
class	cv::videostab::FromFileMotionReader
class	cv::videostab::GaussianMotionFilter
class	cv::videostab::ImageMotionEstimatorBase
	Base class for global 2D motion estimation methods which take frames as input. More...
class	cv::videostab::IMotionStabilizer
class	cv::videostab::KeypointBasedMotionEstimator
	Describes a global 2D motion estimation method which uses keypoints detection and optical flow for matching. More...
class	cv::videostab::LpMotionStabilizer
class	cv::videostab::MotionEstimatorBase
	Base class for all global motion estimation methods. More...
class	cv::videostab::MotionEstimatorL1
	Describes a global 2D motion estimation method which minimizes L1 error. More...
class	cv::videostab::MotionEstimatorRansacL2
	Describes a robust RANSAC-based global 2D motion estimation method which minimizes L2 error. More...
class	cv::videostab::MotionFilterBase
class	cv::videostab::MotionStabilizationPipeline
struct	cv::videostab::RansacParams
	Describes RANSAC method parameters. More...
class	cv::videostab::ToFileMotionWriter

Enumerations
enum	cv::videostab::MotionModel {   cv::videostab::MM_TRANSLATION = 0 ,   cv::videostab::MM_TRANSLATION_AND_SCALE = 1 ,   cv::videostab::MM_ROTATION = 2 ,   cv::videostab::MM_RIGID = 3 ,   cv::videostab::MM_SIMILARITY = 4 ,   cv::videostab::MM_AFFINE = 5 ,   cv::videostab::MM_HOMOGRAPHY = 6 ,   cv::videostab::MM_UNKNOWN = 7 }
	Describes motion model between two point clouds. More...

Functions
	cv::videostab::GaussianMotionFilter::GaussianMotionFilter (int radius=15, float stdev=-1.f)
	cv::videostab::RansacParams::RansacParams (int size, float thresh, float eps, float prob)
	Constructor.
Mat	cv::videostab::ensureInclusionConstraint (const Mat &M, Size size, float trimRatio)
Mat	cv::videostab::estimateGlobalMotionLeastSquares (InputOutputArray points0, InputOutputArray points1, int model=MM_AFFINE, float *rmse=0)
	Estimates best global motion between two 2D point clouds in the least-squares sense.
Mat	cv::videostab::estimateGlobalMotionRansac (InputArray points0, InputArray points1, int model=MM_AFFINE, const RansacParams &params=RansacParams::default2dMotion(MM_AFFINE), float *rmse=0, int *ninliers=0)
	Estimates best global motion between two 2D point clouds robustly (using RANSAC method).
float	cv::videostab::estimateOptimalTrimRatio (const Mat &M, Size size)
Mat	cv::videostab::getMotion (int from, int to, const std::vector< Mat > &motions)
	Computes motion between two frames assuming that all the intermediate motions are known.

Enumeration Type Documentation

MotionModel

enum cv::videostab::MotionModel

#include <opencv2/videostab/motion_core.hpp>

Describes motion model between two point clouds.

Enumerator
MM_TRANSLATION  Python: cv.videostab.MM_TRANSLATION
MM_TRANSLATION_AND_SCALE  Python: cv.videostab.MM_TRANSLATION_AND_SCALE
MM_ROTATION  Python: cv.videostab.MM_ROTATION
MM_RIGID  Python: cv.videostab.MM_RIGID
MM_SIMILARITY  Python: cv.videostab.MM_SIMILARITY
MM_AFFINE  Python: cv.videostab.MM_AFFINE
MM_HOMOGRAPHY  Python: cv.videostab.MM_HOMOGRAPHY
MM_UNKNOWN  Python: cv.videostab.MM_UNKNOWN

Function Documentation

GaussianMotionFilter()

cv::videostab::GaussianMotionFilter::GaussianMotionFilter ( int  radius = 15, float  stdev = -1.f  )

inline

#include <opencv2/videostab/motion_stabilizing.hpp>

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RansacParams()

cv::videostab::RansacParams::RansacParams ( int  size, float  thresh, float  eps, float  prob  )

inline

#include <opencv2/videostab/motion_core.hpp>

Constructor.

Parameters

size	Subset size.
thresh	Maximum re-projection error value to classify as inlier.
eps	Maximum ratio of incorrect correspondences.
prob	Required success probability.

ensureInclusionConstraint()

Mat cv::videostab::ensureInclusionConstraint	(	const Mat &	M,
		Size	size,
		float	trimRatio
	)

#include <opencv2/videostab/motion_stabilizing.hpp>

estimateGlobalMotionLeastSquares()

Mat cv::videostab::estimateGlobalMotionLeastSquares	(	InputOutputArray	points0,
		InputOutputArray	points1,
		int	model = MM_AFFINE,
		float *	rmse = 0
	)

#include <opencv2/videostab/global_motion.hpp>

Estimates best global motion between two 2D point clouds in the least-squares sense.

Note

Works in-place and changes input point arrays.

Parameters

points0	Source set of 2D points (32F).
points1	Destination set of 2D points (32F).
model	Motion model (up to MM_AFFINE).
rmse	Final root-mean-square error.

Returns

3x3 2D transformation matrix (32F).

estimateGlobalMotionRansac()

Mat cv::videostab::estimateGlobalMotionRansac	(	InputArray	points0,
		InputArray	points1,
		int	model = MM_AFFINE,
		const RansacParams &	params = RansacParams::default2dMotion(MM_AFFINE),
		float *	rmse = 0,
		int *	ninliers = 0
	)

#include <opencv2/videostab/global_motion.hpp>

Estimates best global motion between two 2D point clouds robustly (using RANSAC method).

Parameters

points0	Source set of 2D points (32F).
points1	Destination set of 2D points (32F).
model	Motion model. See cv::videostab::MotionModel.
params	RANSAC method parameters. See videostab::RansacParams.
rmse	Final root-mean-square error.
ninliers	Final number of inliers.

estimateOptimalTrimRatio()

float cv::videostab::estimateOptimalTrimRatio	(	const Mat &	M,
		Size	size
	)

#include <opencv2/videostab/motion_stabilizing.hpp>

getMotion()

Mat cv::videostab::getMotion	(	int	from,
		int	to,
		const std::vector< Mat > &	motions
	)

#include <opencv2/videostab/global_motion.hpp>

Computes motion between two frames assuming that all the intermediate motions are known.

Parameters

from	Source frame index.
to	Destination frame index.
motions	Pair-wise motions. motions[i] denotes motion from the frame i to the frame i+1

Returns

Motion from the Source frame to the Destination frame.

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