Image Processing

ocl::cornerHarris

Returns void

C++: void cornerHarris(const oclMat& src, oclMat& dst, int blockSize, int ksize, double k, int bordertype=cv::BORDER_DEFAULT)

Parameters:

• src – Source image. Only CV_8UC1 and CV_32FC1 images are supported now.
• dst – Destination image containing cornerness values. It has the same size as src and CV_32FC1 type.
• blockSize – Neighborhood size
• ksize – Aperture parameter for the Sobel operator
• k – Harris detector free parameter
• bordertype – Pixel extrapolation method. Only BORDER_REFLECT101, BORDER_REFLECT, BORDER_CONSTANT and BORDER_REPLICATE are supported now.

Calculate Harris corner.

ocl::cornerMinEigenVal

Returns void

C++: void cornerMinEigenVal(const oclMat& src, oclMat& dst, int blockSize, int ksize, int bordertype=cv::BORDER_DEFAULT)

Parameters:

• src – Source image. Only CV_8UC1 and CV_32FC1 images are supported now.
• dst – Destination image containing cornerness values. It has the same size as src and CV_32FC1 type.
• blockSize – Neighborhood size
• ksize – Aperture parameter for the Sobel operator
• bordertype – Pixel extrapolation method. Only BORDER_REFLECT101, BORDER_REFLECT, BORDER_CONSTANT and BORDER_REPLICATE are supported now.

Calculate MinEigenVal.

ocl::calcHist

Returns void

C++: void calcHist(const oclMat& mat_src, oclMat& mat_hist)

Parameters:

• src – Source arrays. They all should have the same depth, CV 8U, and the same size. Each of them can have an arbitrary number of channels.
• dst – The output histogram, a dense or sparse dims-dimensional

Calculates histogram of one or more arrays. Supports only 8UC1 data type.

ocl::remap

Returns void

C++: void remap(const oclMat& src, oclMat& dst, oclMat& map1, oclMat& map2, int interpolation, int bordertype, const Scalar& value=Scalar())

Parameters:

• src – Source image. Only CV_8UC1 and CV_32FC1 images are supported now.
• dst – Destination image containing cornerness values. It has the same size as src and CV_32FC1 type.
• map1 – The first map of either (x,y) points or just x values having the type CV_16SC2 , CV_32FC1 , or CV_32FC2 . See covertMaps() for details on converting a floating point representation to fixed-point for speed.
• map2 – The second map of y values having the type CV_32FC1 , or none (empty map if map1 is (x,y) points), respectively.
• interpolation – The interpolation method
• bordertype – Pixel extrapolation method. Only BORDER_CONSTANT are supported now.
• value – The border value if borderType==BORDER CONSTANT

The function remap transforms the source image using the specified map: dst (x ,y) = src (map1(x , y) , map2(x , y)) where values of pixels with non-integer coordinates are computed using one of available interpolation methods. map1 and map2 can be encoded as separate floating-point maps in map1 and map2 respectively, or interleaved floating-point maps of (x,y) in map1. Supports CV_8UC1, CV_8UC3, CV_8UC4, CV_32FC1 , CV_32FC3 and CV_32FC4 data types.

ocl::resize

Returns void

C++: void resize(const oclMat& src, oclMat& dst, Size dsize, double fx=0, double fy=0, int interpolation=INTER_LINEAR)

Parameters:

• src – Source image.
• dst – Destination image.
• dsize – he destination image size. If it is zero, then it is computed as: dsize = Size(round(fx*src.cols), round(fy*src.rows)). Either dsize or both fx or fy must be non-zero.
• fx – The scale factor along the horizontal axis. When 0, it is computed as (double)dsize.width/src.cols
• fy – The scale factor along the vertical axis. When 0, it is computed as (double)dsize.height/src.rows
• interpolation – The interpolation method: INTER NEAREST or INTER LINEAR

Resizes an image. Supports CV_8UC1, CV_8UC3, CV_8UC4, CV_32FC1 , CV_32FC3 and CV_32FC4 data types.

ocl::warpAffine

Returns void

C++: void warpAffine(const oclMat& src, oclMat& dst, const Mat& M, Size dsize, int flags=INTER_LINEAR)

Parameters:

• src – Source image.
• dst – Destination image.
• M – 2times 3 transformation matrix
• dsize – Size of the destination image
• flags – A combination of interpolation methods, see cv::resize, and the optional flag WARP INVERSE MAP that means that M is the inverse transformation (dst to $src)

The function warpAffine transforms the source image using the specified matrix. Supports INTER_NEAREST, INTER_LINEAR, INTER_CUBIC types.

ocl::warpPerspective

Returns void

C++: void warpPerspective(const oclMat& src, oclMat& dst, const Mat& M, Size dsize, int flags=INTER_LINEAR)

Parameters:

• src – Source image.
• dst – Destination image.
• M – 2times 3 transformation matrix
• dsize – Size of the destination image
• flags – A combination of interpolation methods, see cv::resize, and the optional flag WARP INVERSE MAP that means that M is the inverse transformation (dst to $src)

Applies a perspective transformation to an image. Supports INTER_NEAREST, INTER_LINEAR, INTER_CUBIC types.

ocl::cvtColor

Returns void

C++: void cvtColor(const oclMat& src, oclMat& dst, int code, int dcn=0)

Parameters:

• src – Source image.
• dst – Destination image.

:param code:The color space conversion code

Parameters:

• dcn – The number of channels in the destination image; if the parameter is 0, the number of the channels will be derived automatically from src and the code

Converts image from one color space to another.For now, only RGB2GRAY is supportted. Supports.CV_8UC1,CV_8UC4,CV_32SC1,CV_32SC4,CV_32FC1,CV_32FC4

ocl::threshold

Returns Threshold value

C++: double threshold(const oclMat& src, oclMat& dst, double thresh, double maxVal, int type=THRESH_TRUNC)

Parameters:

• src – The source array
• dst – Destination array; will have the same size and the same type as src
• thresh – Threshold value
• maxVal – Maximum value to use with THRESH BINARY and THRESH BINARY INV thresholding types
• type – Thresholding type

The function applies fixed-level thresholding to a single-channel array. The function is typically used to get a bi-level (binary) image out of a grayscale image or for removing a noise, i.e. filtering out pixels with too small or too large values. There are several types of thresholding that the function supports that are determined by thresholdType. Supports only CV_32FC1 and CV_8UC1 data type.

ocl::buildWarpPlaneMaps

Builds plane warping maps.

C++: void ocl::buildWarpPlaneMaps(Size src_size, Rect dst_roi, const Mat& R, double f, double s, double dist, oclMat& map_x, oclMat& map_y)

ocl::buildWarpCylindricalMaps

Builds cylindrical warping maps.

C++: void ocl::buildWarpCylindricalMaps(Size src_size, Rect dst_roi, const Mat& R, double f, double s, oclMat& map_x, oclMat& map_y)

ocl::buildWarpSphericalMaps

Builds spherical warping maps.

C++: void ocl::buildWarpSphericalMaps(Size src_size, Rect dst_roi, const Mat& R, double f, double s, oclMat& map_x, oclMat& map_y)

ocl::buildWarpPerspectiveMaps

Builds transformation maps for perspective transformation.

C++: void buildWarpAffineMaps(const Mat& M, bool inverse, Size dsize, oclMat& xmap, oclMat& ymap)

Parameters:

• M – 3x3 transformation matrix.
• inverse – Flag specifying that M is an inverse transformation ( dst=>src ).
• dsize – Size of the destination image.
• xmap – X values with CV_32FC1 type.
• ymap – Y values with CV_32FC1 type.

See also

ocl::warpPerspective() , ocl::remap()

ocl::buildWarpAffineMaps

Builds transformation maps for affine transformation.

C++: void buildWarpAffineMaps(const Mat& M, bool inverse, Size dsize, oclMat& xmap, oclMat& ymap)

Parameters:

• M – 2x3 transformation matrix.
• inverse – Flag specifying that M is an inverse transformation ( dst=>src ).
• dsize – Size of the destination image.
• xmap – X values with CV_32FC1 type.
• ymap – Y values with CV_32FC1 type.

See also

ocl::warpAffine() , ocl::remap()

ocl::PyrLKOpticalFlow

class ocl::PyrLKOpticalFlow

Class used for calculating an optical flow.

class PyrLKOpticalFlow
{
public:
    PyrLKOpticalFlow();

    void sparse(const oclMat& prevImg, const oclMat& nextImg, const oclMat& prevPts, oclMat& nextPts,
        oclMat& status, oclMat* err = 0);

    void dense(const oclMat& prevImg, const oclMat& nextImg, oclMat& u, oclMat& v, oclMat* err = 0);

    Size winSize;
    int maxLevel;
    int iters;
    double derivLambda;
    bool useInitialFlow;
    float minEigThreshold;
    bool getMinEigenVals;

    void releaseMemory();
};

The class can calculate an optical flow for a sparse feature set or dense optical flow using the iterative Lucas-Kanade method with pyramids.

See also

calcOpticalFlowPyrLK()

ocl::PyrLKOpticalFlow::sparse

Calculate an optical flow for a sparse feature set.

C++: void ocl::PyrLKOpticalFlow::sparse(const oclMat& prevImg, const oclMat& nextImg, const oclMat& prevPts, oclMat& nextPts, oclMat& status, oclMat* err=0)

Parameters:

• prevImg – First 8-bit input image (supports both grayscale and color images).
• nextImg – Second input image of the same size and the same type as prevImg .
• prevPts – Vector of 2D points for which the flow needs to be found. It must be one row matrix with CV_32FC2 type.
• 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.
• 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.
• 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.

See also

calcOpticalFlowPyrLK()

ocl::PyrLKOpticalFlow::dense

Calculate dense optical flow.

C++: void ocl::PyrLKOpticalFlow::dense(const oclMat& prevImg, const oclMat& nextImg, oclMat& u, oclMat& v, oclMat* err=0)

Parameters:

• prevImg – First 8-bit grayscale input image.
• nextImg – Second input image of the same size and the same type as prevImg .
• u – Horizontal component of the optical flow of the same size as input images, 32-bit floating-point, single-channel
• v – Vertical component of the optical flow of the same size as input images, 32-bit floating-point, single-channel
• 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.

ocl::PyrLKOpticalFlow::releaseMemory

Releases inner buffers memory.

C++: void ocl::PyrLKOpticalFlow::releaseMemory()

ocl::interpolateFrames

Interpolate frames (images) using provided optical flow (displacement field).

C++: void ocl::interpolateFrames(const oclMat& frame0, const oclMat& frame1, const oclMat& fu, const oclMat& fv, const oclMat& bu, const oclMat& bv, float pos, oclMat& newFrame, oclMat& buf)

Parameters:

• frame0 – First frame (32-bit floating point images, single channel).
• frame1 – Second frame. Must have the same type and size as frame0 .
• fu – Forward horizontal displacement.
• fv – Forward vertical displacement.
• bu – Backward horizontal displacement.
• bv – Backward vertical displacement.
• pos – New frame position.
• newFrame – Output image.
• buf – Temporary buffer, will have width x 6*height size, CV_32FC1 type and contain 6 oclMat: 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.