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833 lines
28 KiB
ReStructuredText
833 lines
28 KiB
ReStructuredText
Video Analysis
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==============
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.. highlight:: cpp
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gpu::BroxOpticalFlow
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--------------------
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.. ocv:class:: gpu::BroxOpticalFlow
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Class computing the optical flow for two images using Brox et al Optical Flow algorithm ([Brox2004]_). ::
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class BroxOpticalFlow
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{
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public:
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BroxOpticalFlow(float alpha_, float gamma_, float scale_factor_, int inner_iterations_, int outer_iterations_, int solver_iterations_);
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//! Compute optical flow
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//! frame0 - source frame (supports only CV_32FC1 type)
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//! frame1 - frame to track (with the same size and type as frame0)
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//! u - flow horizontal component (along x axis)
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//! v - flow vertical component (along y axis)
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void operator ()(const GpuMat& frame0, const GpuMat& frame1, GpuMat& u, GpuMat& v, Stream& stream = Stream::Null());
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//! flow smoothness
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float alpha;
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//! gradient constancy importance
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float gamma;
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//! pyramid scale factor
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float scale_factor;
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//! number of lagged non-linearity iterations (inner loop)
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int inner_iterations;
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//! number of warping iterations (number of pyramid levels)
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int outer_iterations;
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//! number of linear system solver iterations
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int solver_iterations;
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GpuMat buf;
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};
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gpu::GoodFeaturesToTrackDetector_GPU
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------------------------------------
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.. ocv:class:: gpu::GoodFeaturesToTrackDetector_GPU
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Class used for strong corners detection on an image. ::
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class GoodFeaturesToTrackDetector_GPU
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{
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public:
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explicit GoodFeaturesToTrackDetector_GPU(int maxCorners_ = 1000, double qualityLevel_ = 0.01, double minDistance_ = 0.0,
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int blockSize_ = 3, bool useHarrisDetector_ = false, double harrisK_ = 0.04);
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void operator ()(const GpuMat& image, GpuMat& corners, const GpuMat& mask = GpuMat());
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int maxCorners;
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double qualityLevel;
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double minDistance;
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int blockSize;
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bool useHarrisDetector;
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double harrisK;
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void releaseMemory();
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};
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The class finds the most prominent corners in the image.
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.. seealso:: :ocv:func:`goodFeaturesToTrack`
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gpu::GoodFeaturesToTrackDetector_GPU::GoodFeaturesToTrackDetector_GPU
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---------------------------------------------------------------------
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Constructor.
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.. ocv:function:: gpu::GoodFeaturesToTrackDetector_GPU::GoodFeaturesToTrackDetector_GPU(int maxCorners = 1000, double qualityLevel = 0.01, double minDistance = 0.0, int blockSize = 3, bool useHarrisDetector = false, double harrisK = 0.04)
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:param maxCorners: Maximum number of corners to return. If there are more corners than are found, the strongest of them is returned.
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:param qualityLevel: Parameter characterizing the minimal accepted quality of image corners. The parameter value is multiplied by the best corner quality measure, which is the minimal eigenvalue (see :ocv:func:`gpu::cornerMinEigenVal` ) or the Harris function response (see :ocv:func:`gpu::cornerHarris` ). The corners with the quality measure less than the product are rejected. For example, if the best corner has the quality measure = 1500, and the ``qualityLevel=0.01`` , then all the corners with the quality measure less than 15 are rejected.
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:param minDistance: Minimum possible Euclidean distance between the returned corners.
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:param blockSize: Size of an average block for computing a derivative covariation matrix over each pixel neighborhood. See :ocv:func:`cornerEigenValsAndVecs` .
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:param useHarrisDetector: Parameter indicating whether to use a Harris detector (see :ocv:func:`gpu::cornerHarris`) or :ocv:func:`gpu::cornerMinEigenVal`.
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:param harrisK: Free parameter of the Harris detector.
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gpu::GoodFeaturesToTrackDetector_GPU::operator ()
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-------------------------------------------------
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Finds the most prominent corners in the image.
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.. ocv:function:: void gpu::GoodFeaturesToTrackDetector_GPU::operator ()(const GpuMat& image, GpuMat& corners, const GpuMat& mask = GpuMat())
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:param image: Input 8-bit, single-channel image.
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:param corners: Output vector of detected corners (it will be one row matrix with CV_32FC2 type).
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:param mask: Optional region of interest. If the image is not empty (it needs to have the type ``CV_8UC1`` and the same size as ``image`` ), it specifies the region in which the corners are detected.
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.. seealso:: :ocv:func:`goodFeaturesToTrack`
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gpu::GoodFeaturesToTrackDetector_GPU::releaseMemory
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---------------------------------------------------
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Releases inner buffers memory.
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.. ocv:function:: void gpu::GoodFeaturesToTrackDetector_GPU::releaseMemory()
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gpu::FarnebackOpticalFlow
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-------------------------
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.. ocv:class:: gpu::FarnebackOpticalFlow
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Class computing a dense optical flow using the Gunnar Farneback’s algorithm. ::
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class CV_EXPORTS FarnebackOpticalFlow
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{
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public:
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FarnebackOpticalFlow()
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{
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numLevels = 5;
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pyrScale = 0.5;
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fastPyramids = false;
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winSize = 13;
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numIters = 10;
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polyN = 5;
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polySigma = 1.1;
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flags = 0;
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}
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int numLevels;
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double pyrScale;
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bool fastPyramids;
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int winSize;
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int numIters;
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int polyN;
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double polySigma;
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int flags;
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void operator ()(const GpuMat &frame0, const GpuMat &frame1, GpuMat &flowx, GpuMat &flowy, Stream &s = Stream::Null());
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void releaseMemory();
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private:
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/* hidden */
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};
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gpu::FarnebackOpticalFlow::operator ()
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--------------------------------------
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Computes a dense optical flow using the Gunnar Farneback’s algorithm.
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.. ocv:function:: void gpu::FarnebackOpticalFlow::operator ()(const GpuMat &frame0, const GpuMat &frame1, GpuMat &flowx, GpuMat &flowy, Stream &s = Stream::Null())
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:param frame0: First 8-bit gray-scale input image
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:param frame1: Second 8-bit gray-scale input image
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:param flowx: Flow horizontal component
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:param flowy: Flow vertical component
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:param s: Stream
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.. seealso:: :ocv:func:`calcOpticalFlowFarneback`
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gpu::FarnebackOpticalFlow::releaseMemory
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----------------------------------------
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Releases unused auxiliary memory buffers.
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.. ocv:function:: void gpu::FarnebackOpticalFlow::releaseMemory()
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gpu::PyrLKOpticalFlow
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---------------------
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.. ocv:class:: gpu::PyrLKOpticalFlow
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Class used for calculating an optical flow. ::
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class PyrLKOpticalFlow
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{
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public:
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PyrLKOpticalFlow();
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void sparse(const GpuMat& prevImg, const GpuMat& nextImg, const GpuMat& prevPts, GpuMat& nextPts,
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GpuMat& status, GpuMat* err = 0);
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void dense(const GpuMat& prevImg, const GpuMat& nextImg, GpuMat& u, GpuMat& v, GpuMat* err = 0);
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Size winSize;
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int maxLevel;
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int iters;
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double derivLambda;
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bool useInitialFlow;
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float minEigThreshold;
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bool getMinEigenVals;
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void releaseMemory();
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};
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The class can calculate an optical flow for a sparse feature set or dense optical flow using the iterative Lucas-Kanade method with pyramids.
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.. seealso:: :ocv:func:`calcOpticalFlowPyrLK`
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gpu::PyrLKOpticalFlow::sparse
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-----------------------------
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Calculate an optical flow for a sparse feature set.
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.. ocv:function:: void gpu::PyrLKOpticalFlow::sparse(const GpuMat& prevImg, const GpuMat& nextImg, const GpuMat& prevPts, GpuMat& nextPts, GpuMat& status, GpuMat* err = 0)
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:param prevImg: First 8-bit input image (supports both grayscale and color images).
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:param nextImg: Second input image of the same size and the same type as ``prevImg`` .
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:param prevPts: Vector of 2D points for which the flow needs to be found. It must be one row matrix with CV_32FC2 type.
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:param nextPts: Output vector of 2D points (with single-precision floating-point coordinates) containing the calculated new positions of input features in the second image. When ``useInitialFlow`` is true, the vector must have the same size as in the input.
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:param status: Output status vector (CV_8UC1 type). Each element of the vector is set to 1 if the flow for the corresponding features has been found. Otherwise, it is set to 0.
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:param err: Output vector (CV_32FC1 type) that contains the difference between patches around the original and moved points or min eigen value if ``getMinEigenVals`` is checked. It can be NULL, if not needed.
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.. seealso:: :ocv:func:`calcOpticalFlowPyrLK`
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gpu::PyrLKOpticalFlow::dense
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-----------------------------
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Calculate dense optical flow.
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.. ocv:function:: void gpu::PyrLKOpticalFlow::dense(const GpuMat& prevImg, const GpuMat& nextImg, GpuMat& u, GpuMat& v, GpuMat* err = 0)
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:param prevImg: First 8-bit grayscale input image.
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:param nextImg: Second input image of the same size and the same type as ``prevImg`` .
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:param u: Horizontal component of the optical flow of the same size as input images, 32-bit floating-point, single-channel
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:param v: Vertical component of the optical flow of the same size as input images, 32-bit floating-point, single-channel
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:param err: Output vector (CV_32FC1 type) that contains the difference between patches around the original and moved points or min eigen value if ``getMinEigenVals`` is checked. It can be NULL, if not needed.
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gpu::PyrLKOpticalFlow::releaseMemory
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------------------------------------
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Releases inner buffers memory.
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.. ocv:function:: void gpu::PyrLKOpticalFlow::releaseMemory()
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gpu::interpolateFrames
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----------------------
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Interpolates frames (images) using provided optical flow (displacement field).
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.. ocv:function:: void gpu::interpolateFrames(const GpuMat& frame0, const GpuMat& frame1, const GpuMat& fu, const GpuMat& fv, const GpuMat& bu, const GpuMat& bv, float pos, GpuMat& newFrame, GpuMat& buf, Stream& stream = Stream::Null())
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:param frame0: First frame (32-bit floating point images, single channel).
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:param frame1: Second frame. Must have the same type and size as ``frame0`` .
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:param fu: Forward horizontal displacement.
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:param fv: Forward vertical displacement.
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:param bu: Backward horizontal displacement.
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:param bv: Backward vertical displacement.
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:param pos: New frame position.
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:param newFrame: Output image.
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:param buf: Temporary buffer, will have width x 6*height size, CV_32FC1 type and contain 6 GpuMat: occlusion masks for first frame, occlusion masks for second, interpolated forward horizontal flow, interpolated forward vertical flow, interpolated backward horizontal flow, interpolated backward vertical flow.
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:param stream: Stream for the asynchronous version.
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gpu::FGDStatModel
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-----------------
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.. ocv:class:: gpu::FGDStatModel
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Class used for background/foreground segmentation. ::
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class FGDStatModel
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{
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public:
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struct Params
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{
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...
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};
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explicit FGDStatModel(int out_cn = 3);
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explicit FGDStatModel(const cv::gpu::GpuMat& firstFrame, const Params& params = Params(), int out_cn = 3);
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~FGDStatModel();
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void create(const cv::gpu::GpuMat& firstFrame, const Params& params = Params());
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void release();
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int update(const cv::gpu::GpuMat& curFrame);
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//8UC3 or 8UC4 reference background image
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cv::gpu::GpuMat background;
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//8UC1 foreground image
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cv::gpu::GpuMat foreground;
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std::vector< std::vector<cv::Point> > foreground_regions;
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};
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The class discriminates between foreground and background pixels by building and maintaining a model of the background. Any pixel which does not fit this model is then deemed to be foreground. The class implements algorithm described in [FGD2003]_.
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The results are available through the class fields:
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.. ocv:member:: cv::gpu::GpuMat background
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The output background image.
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.. ocv:member:: cv::gpu::GpuMat foreground
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The output foreground mask as an 8-bit binary image.
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.. ocv:member:: cv::gpu::GpuMat foreground_regions
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The output foreground regions calculated by :ocv:func:`findContours`.
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gpu::FGDStatModel::FGDStatModel
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-------------------------------
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Constructors.
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.. ocv:function:: gpu::FGDStatModel::FGDStatModel(int out_cn = 3)
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.. ocv:function:: gpu::FGDStatModel::FGDStatModel(const cv::gpu::GpuMat& firstFrame, const Params& params = Params(), int out_cn = 3)
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:param firstFrame: First frame from video stream. Supports 3- and 4-channels input ( ``CV_8UC3`` and ``CV_8UC4`` ).
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:param params: Algorithm's parameters. See [FGD2003]_ for explanation.
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:param out_cn: Channels count in output result and inner buffers. Can be 3 or 4. 4-channels version requires more memory, but works a bit faster.
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.. seealso:: :ocv:func:`gpu::FGDStatModel::create`
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gpu::FGDStatModel::create
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-------------------------
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Initializes background model.
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.. ocv:function:: void gpu::FGDStatModel::create(const cv::gpu::GpuMat& firstFrame, const Params& params = Params())
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:param firstFrame: First frame from video stream. Supports 3- and 4-channels input ( ``CV_8UC3`` and ``CV_8UC4`` ).
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:param params: Algorithm's parameters. See [FGD2003]_ for explanation.
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gpu::FGDStatModel::release
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--------------------------
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Releases all inner buffer's memory.
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.. ocv:function:: void gpu::FGDStatModel::release()
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gpu::FGDStatModel::update
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--------------------------
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Updates the background model and returns foreground regions count.
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.. ocv:function:: int gpu::FGDStatModel::update(const cv::gpu::GpuMat& curFrame);
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:param curFrame: Next video frame.
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gpu::VideoWriter_GPU
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---------------------
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Video writer class.
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.. ocv:class:: gpu::VideoWriter_GPU
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The class uses H264 video codec.
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.. note:: Currently only Windows platform is supported.
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gpu::VideoWriter_GPU::VideoWriter_GPU
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-------------------------------------
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Constructors.
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.. ocv:function:: gpu::VideoWriter_GPU::VideoWriter_GPU()
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.. ocv:function:: gpu::VideoWriter_GPU::VideoWriter_GPU(const std::string& fileName, cv::Size frameSize, double fps, SurfaceFormat format = SF_BGR)
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.. ocv:function:: gpu::VideoWriter_GPU::VideoWriter_GPU(const std::string& fileName, cv::Size frameSize, double fps, const EncoderParams& params, SurfaceFormat format = SF_BGR)
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.. ocv:function:: gpu::VideoWriter_GPU::VideoWriter_GPU(const cv::Ptr<EncoderCallBack>& encoderCallback, cv::Size frameSize, double fps, SurfaceFormat format = SF_BGR)
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.. ocv:function:: gpu::VideoWriter_GPU::VideoWriter_GPU(const cv::Ptr<EncoderCallBack>& encoderCallback, cv::Size frameSize, double fps, const EncoderParams& params, SurfaceFormat format = SF_BGR)
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:param fileName: Name of the output video file. Only AVI file format is supported.
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:param frameSize: Size of the input video frames.
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:param fps: Framerate of the created video stream.
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:param params: Encoder parameters. See :ocv:class:`gpu::VideoWriter_GPU::EncoderParams` .
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:param format: Surface format of input frames ( ``SF_UYVY`` , ``SF_YUY2`` , ``SF_YV12`` , ``SF_NV12`` , ``SF_IYUV`` , ``SF_BGR`` or ``SF_GRAY``). BGR or gray frames will be converted to YV12 format before encoding, frames with other formats will be used as is.
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:param encoderCallback: Callbacks for video encoder. See :ocv:class:`gpu::VideoWriter_GPU::EncoderCallBack` . Use it if you want to work with raw video stream.
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The constructors initialize video writer. FFMPEG is used to write videos. User can implement own multiplexing with :ocv:class:`gpu::VideoWriter_GPU::EncoderCallBack` .
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gpu::VideoWriter_GPU::open
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--------------------------
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Initializes or reinitializes video writer.
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.. ocv:function:: void gpu::VideoWriter_GPU::open(const std::string& fileName, cv::Size frameSize, double fps, SurfaceFormat format = SF_BGR)
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.. ocv:function:: void gpu::VideoWriter_GPU::open(const std::string& fileName, cv::Size frameSize, double fps, const EncoderParams& params, SurfaceFormat format = SF_BGR)
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.. ocv:function:: void gpu::VideoWriter_GPU::open(const cv::Ptr<EncoderCallBack>& encoderCallback, cv::Size frameSize, double fps, SurfaceFormat format = SF_BGR)
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.. ocv:function:: void gpu::VideoWriter_GPU::open(const cv::Ptr<EncoderCallBack>& encoderCallback, cv::Size frameSize, double fps, const EncoderParams& params, SurfaceFormat format = SF_BGR)
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The method opens video writer. Parameters are the same as in the constructor :ocv:func:`gpu::VideoWriter_GPU::VideoWriter_GPU` . The method throws :ocv:class:`Exception` if error occurs.
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gpu::VideoWriter_GPU::isOpened
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------------------------------
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Returns true if video writer has been successfully initialized.
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.. ocv:function:: bool gpu::VideoWriter_GPU::isOpened() const
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gpu::VideoWriter_GPU::close
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---------------------------
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Releases the video writer.
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.. ocv:function:: void gpu::VideoWriter_GPU::close()
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gpu::VideoWriter_GPU::write
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---------------------------
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Writes the next video frame.
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.. ocv:function:: void gpu::VideoWriter_GPU::write(const cv::gpu::GpuMat& image, bool lastFrame = false)
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:param image: The written frame.
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:param lastFrame: Indicates that it is end of stream. The parameter can be ignored.
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The method write the specified image to video file. The image must have the same size and the same surface format as has been specified when opening the video writer.
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gpu::VideoWriter_GPU::EncoderParams
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-----------------------------------
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.. ocv:struct:: gpu::VideoWriter_GPU::EncoderParams
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Different parameters for CUDA video encoder. ::
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struct EncoderParams
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{
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int P_Interval; // NVVE_P_INTERVAL,
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int IDR_Period; // NVVE_IDR_PERIOD,
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int DynamicGOP; // NVVE_DYNAMIC_GOP,
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int RCType; // NVVE_RC_TYPE,
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int AvgBitrate; // NVVE_AVG_BITRATE,
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int PeakBitrate; // NVVE_PEAK_BITRATE,
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int QP_Level_Intra; // NVVE_QP_LEVEL_INTRA,
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int QP_Level_InterP; // NVVE_QP_LEVEL_INTER_P,
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int QP_Level_InterB; // NVVE_QP_LEVEL_INTER_B,
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int DeblockMode; // NVVE_DEBLOCK_MODE,
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int ProfileLevel; // NVVE_PROFILE_LEVEL,
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int ForceIntra; // NVVE_FORCE_INTRA,
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int ForceIDR; // NVVE_FORCE_IDR,
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int ClearStat; // NVVE_CLEAR_STAT,
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int DIMode; // NVVE_SET_DEINTERLACE,
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int Presets; // NVVE_PRESETS,
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int DisableCabac; // NVVE_DISABLE_CABAC,
|
||
int NaluFramingType; // NVVE_CONFIGURE_NALU_FRAMING_TYPE
|
||
int DisableSPSPPS; // NVVE_DISABLE_SPS_PPS
|
||
|
||
EncoderParams();
|
||
explicit EncoderParams(const std::string& configFile);
|
||
|
||
void load(const std::string& configFile);
|
||
void save(const std::string& configFile) const;
|
||
};
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderParams::EncoderParams
|
||
--------------------------------------------------
|
||
Constructors.
|
||
|
||
.. ocv:function:: gpu::VideoWriter_GPU::EncoderParams::EncoderParams()
|
||
.. ocv:function:: gpu::VideoWriter_GPU::EncoderParams::EncoderParams(const std::string& configFile)
|
||
|
||
:param configFile: Config file name.
|
||
|
||
Creates default parameters or reads parameters from config file.
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderParams::load
|
||
-----------------------------------------
|
||
Reads parameters from config file.
|
||
|
||
.. ocv:function:: void gpu::VideoWriter_GPU::EncoderParams::load(const std::string& configFile)
|
||
|
||
:param configFile: Config file name.
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderParams::save
|
||
-----------------------------------------
|
||
Saves parameters to config file.
|
||
|
||
.. ocv:function:: void gpu::VideoWriter_GPU::EncoderParams::save(const std::string& configFile) const
|
||
|
||
:param configFile: Config file name.
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderCallBack
|
||
-------------------------------------
|
||
.. ocv:class:: gpu::VideoWriter_GPU::EncoderCallBack
|
||
|
||
Callbacks for CUDA video encoder. ::
|
||
|
||
class EncoderCallBack
|
||
{
|
||
public:
|
||
enum PicType
|
||
{
|
||
IFRAME = 1,
|
||
PFRAME = 2,
|
||
BFRAME = 3
|
||
};
|
||
|
||
virtual ~EncoderCallBack() {}
|
||
|
||
virtual unsigned char* acquireBitStream(int* bufferSize) = 0;
|
||
virtual void releaseBitStream(unsigned char* data, int size) = 0;
|
||
virtual void onBeginFrame(int frameNumber, PicType picType) = 0;
|
||
virtual void onEndFrame(int frameNumber, PicType picType) = 0;
|
||
};
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderCallBack::acquireBitStream
|
||
-------------------------------------------------------
|
||
Callback function to signal the start of bitstream that is to be encoded.
|
||
|
||
.. ocv:function:: virtual uchar* gpu::VideoWriter_GPU::EncoderCallBack::acquireBitStream(int* bufferSize) = 0
|
||
|
||
Callback must allocate buffer for CUDA encoder and return pointer to it and it's size.
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderCallBack::releaseBitStream
|
||
-------------------------------------------------------
|
||
Callback function to signal that the encoded bitstream is ready to be written to file.
|
||
|
||
.. ocv:function:: virtual void gpu::VideoWriter_GPU::EncoderCallBack::releaseBitStream(unsigned char* data, int size) = 0
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderCallBack::onBeginFrame
|
||
---------------------------------------------------
|
||
Callback function to signal that the encoding operation on the frame has started.
|
||
|
||
.. ocv:function:: virtual void gpu::VideoWriter_GPU::EncoderCallBack::onBeginFrame(int frameNumber, PicType picType) = 0
|
||
|
||
:param picType: Specify frame type (I-Frame, P-Frame or B-Frame).
|
||
|
||
|
||
|
||
gpu::VideoWriter_GPU::EncoderCallBack::onEndFrame
|
||
-------------------------------------------------
|
||
Callback function signals that the encoding operation on the frame has finished.
|
||
|
||
.. ocv:function:: virtual void gpu::VideoWriter_GPU::EncoderCallBack::onEndFrame(int frameNumber, PicType picType) = 0
|
||
|
||
:param picType: Specify frame type (I-Frame, P-Frame or B-Frame).
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU
|
||
--------------------
|
||
Class for reading video from files.
|
||
|
||
.. ocv:class:: gpu::VideoReader_GPU
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::Codec
|
||
---------------------------
|
||
|
||
Video codecs supported by ocv:class:`gpu::VideoReader_GPU` . ::
|
||
|
||
enum Codec
|
||
{
|
||
MPEG1 = 0,
|
||
MPEG2,
|
||
MPEG4,
|
||
VC1,
|
||
H264,
|
||
JPEG,
|
||
H264_SVC,
|
||
H264_MVC,
|
||
|
||
Uncompressed_YUV420 = (('I'<<24)|('Y'<<16)|('U'<<8)|('V')), // Y,U,V (4:2:0)
|
||
Uncompressed_YV12 = (('Y'<<24)|('V'<<16)|('1'<<8)|('2')), // Y,V,U (4:2:0)
|
||
Uncompressed_NV12 = (('N'<<24)|('V'<<16)|('1'<<8)|('2')), // Y,UV (4:2:0)
|
||
Uncompressed_YUYV = (('Y'<<24)|('U'<<16)|('Y'<<8)|('V')), // YUYV/YUY2 (4:2:2)
|
||
Uncompressed_UYVY = (('U'<<24)|('Y'<<16)|('V'<<8)|('Y')), // UYVY (4:2:2)
|
||
};
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::ChromaFormat
|
||
----------------------------------
|
||
|
||
Chroma formats supported by ocv:class:`gpu::VideoReader_GPU` . ::
|
||
|
||
enum ChromaFormat
|
||
{
|
||
Monochrome=0,
|
||
YUV420,
|
||
YUV422,
|
||
YUV444,
|
||
};
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::FormatInfo
|
||
--------------------------------
|
||
.. ocv:struct:: gpu::VideoReader_GPU::FormatInfo
|
||
|
||
Struct providing information about video file format. ::
|
||
|
||
struct FormatInfo
|
||
{
|
||
Codec codec;
|
||
ChromaFormat chromaFormat;
|
||
int width;
|
||
int height;
|
||
};
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoReader_GPU
|
||
-------------------------------------
|
||
Constructors.
|
||
|
||
.. ocv:function:: gpu::VideoReader_GPU::VideoReader_GPU()
|
||
.. ocv:function:: gpu::VideoReader_GPU::VideoReader_GPU(const std::string& filename)
|
||
.. ocv:function:: gpu::VideoReader_GPU::VideoReader_GPU(const cv::Ptr<VideoSource>& source)
|
||
|
||
:param filename: Name of the input video file.
|
||
|
||
:param source: Video file parser implemented by user.
|
||
|
||
The constructors initialize video reader. FFMPEG is used to read videos. User can implement own demultiplexing with :ocv:class:`gpu::VideoReader_GPU::VideoSource` .
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::open
|
||
--------------------------
|
||
Initializes or reinitializes video reader.
|
||
|
||
.. ocv:function:: void gpu::VideoReader_GPU::open(const std::string& filename)
|
||
.. ocv:function:: void gpu::VideoReader_GPU::open(const cv::Ptr<VideoSource>& source)
|
||
|
||
The method opens video reader. Parameters are the same as in the constructor :ocv:func:`gpu::VideoReader_GPU::VideoReader_GPU` . The method throws :ocv:class:`Exception` if error occurs.
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::isOpened
|
||
------------------------------
|
||
Returns true if video reader has been successfully initialized.
|
||
|
||
.. ocv:function:: bool gpu::VideoReader_GPU::isOpened() const
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::close
|
||
---------------------------
|
||
Releases the video reader.
|
||
|
||
.. ocv:function:: void gpu::VideoReader_GPU::close()
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::read
|
||
--------------------------
|
||
Grabs, decodes and returns the next video frame.
|
||
|
||
.. ocv:function:: bool gpu::VideoReader_GPU::read(GpuMat& image)
|
||
|
||
If no frames has been grabbed (there are no more frames in video file), the methods return ``false`` . The method throws :ocv:class:`Exception` if error occurs.
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::format
|
||
----------------------------
|
||
Returns information about video file format.
|
||
|
||
.. ocv:function:: FormatInfo gpu::VideoReader_GPU::format() const
|
||
|
||
The method throws :ocv:class:`Exception` if video reader wasn't initialized.
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::dumpFormat
|
||
--------------------------------
|
||
Dump information about video file format to specified stream.
|
||
|
||
.. ocv:function:: void gpu::VideoReader_GPU::dumpFormat(std::ostream& st)
|
||
|
||
:param st: Output stream.
|
||
|
||
The method throws :ocv:class:`Exception` if video reader wasn't initialized.
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource
|
||
-----------------------------------
|
||
.. ocv:class:: gpu::VideoReader_GPU::VideoSource
|
||
|
||
Interface for video demultiplexing. ::
|
||
|
||
class VideoSource
|
||
{
|
||
public:
|
||
VideoSource();
|
||
virtual ~VideoSource() {}
|
||
|
||
virtual FormatInfo format() const = 0;
|
||
virtual void start() = 0;
|
||
virtual void stop() = 0;
|
||
virtual bool isStarted() const = 0;
|
||
virtual bool hasError() const = 0;
|
||
|
||
protected:
|
||
bool parseVideoData(const unsigned char* data, size_t size, bool endOfStream = false);
|
||
};
|
||
|
||
User can implement own demultiplexing by implementing this interface.
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::format
|
||
-----------------------------------------
|
||
Returns information about video file format.
|
||
|
||
.. ocv:function:: virtual FormatInfo gpu::VideoReader_GPU::VideoSource::format() const = 0
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::start
|
||
----------------------------------------
|
||
Starts processing.
|
||
|
||
.. ocv:function:: virtual void gpu::VideoReader_GPU::VideoSource::start() = 0
|
||
|
||
Implementation must create own thread with video processing and call periodic ocv:func:`gpu::VideoReader_GPU::VideoSource::parseVideoData` .
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::stop
|
||
---------------------------------------
|
||
Stops processing.
|
||
|
||
.. ocv:function:: virtual void gpu::VideoReader_GPU::VideoSource::stop() = 0
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::isStarted
|
||
--------------------------------------------
|
||
Returns ``true`` if processing was successfully started.
|
||
|
||
.. ocv:function:: virtual bool gpu::VideoReader_GPU::VideoSource::isStarted() const = 0
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::hasError
|
||
-------------------------------------------
|
||
Returns ``true`` if error occured during processing.
|
||
|
||
.. ocv:function:: virtual bool gpu::VideoReader_GPU::VideoSource::hasError() const = 0
|
||
|
||
|
||
|
||
gpu::VideoReader_GPU::VideoSource::parseVideoData
|
||
-------------------------------------------------
|
||
Parse next video frame. Implementation must call this method after new frame was grabbed.
|
||
|
||
.. ocv:function:: bool gpu::VideoReader_GPU::VideoSource::parseVideoData(const uchar* data, size_t size, bool endOfStream = false)
|
||
|
||
:param data: Pointer to frame data. Can be ``NULL`` if ``endOfStream`` if ``true`` .
|
||
|
||
:param size: Size in bytes of current frame.
|
||
|
||
:param endOfStream: Indicates that it is end of stream.
|
||
|
||
|
||
|
||
.. [Brox2004] T. Brox, A. Bruhn, N. Papenberg, J. Weickert. *High accuracy optical flow estimation based on a theory for warping*. ECCV 2004.
|
||
.. [FGD2003] Liyuan Li, Weimin Huang, Irene Y.H. Gu, and Qi Tian. *Foreground Object Detection from Videos Containing Complex Background*. ACM MM2003 9p, 2003.
|