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Merge pull request #13723 from smirnov-alexey:gapi_add_sobelxy

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* Add Sobel kernel which returns both dx and dy

* Splice dx and dy and extend add_border function

Also change some tests parameters

* Add borderValue parameter in test

* Introduces fluid kernel for sobelxy

Adds tests (basic and performance) on new backend

* Introduces BufHelper struct for some arithmetic
This commit is contained in:
Alexey Smirnov
2019-02-08 16:59:56 +03:00
committed by Alexander Alekhin
parent 766fd20faa
commit b1cc114b7b
11 changed files with 419 additions and 19 deletions
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modules/gapi/include/opencv2/gapi/imgproc.hpp
+59
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@@ -27,6 +27,7 @@
namespace cv { namespace gapi {
namespace imgproc {
using GMat2 = std::tuple<GMat,GMat>;
using GMat3 = std::tuple<GMat,GMat,GMat>; // FIXME: how to avoid this?
G_TYPED_KERNEL(GFilter2D, <GMat(GMat,int,Mat,Point,Scalar,int,Scalar)>,"org.opencv.imgproc.filters.filter2D") {
@@ -83,6 +84,12 @@ namespace imgproc {
}
};
G_TYPED_KERNEL_M(GSobelXY, <GMat2(GMat,int,int,int,double,double,int,Scalar)>, "org.opencv.imgproc.filters.sobelxy") {
static std::tuple<GMatDesc, GMatDesc> outMeta(GMatDesc in, int ddepth, int, int, double, double, int, Scalar) {
return std::make_tuple(in.withDepth(ddepth), in.withDepth(ddepth));
}
};
G_TYPED_KERNEL(GEqHist, <GMat(GMat)>, "org.opencv.imgproc.equalizeHist"){
static GMatDesc outMeta(GMatDesc in) {
return in.withType(CV_8U, 1);
@@ -487,6 +494,58 @@ GAPI_EXPORTS GMat Sobel(const GMat& src, int ddepth, int dx, int dy, int ksize =
int borderType = BORDER_DEFAULT,
const Scalar& borderValue = Scalar(0));
/** @brief Calculates the first, second, third, or mixed image derivatives using an extended Sobel operator.
In all cases except one, the \f$\texttt{ksize} \times \texttt{ksize}\f$ separable kernel is used to
calculate the derivative. When \f$\texttt{ksize = 1}\f$, the \f$3 \times 1\f$ or \f$1 \times 3\f$
kernel is used (that is, no Gaussian smoothing is done). `ksize = 1` can only be used for the first
or the second x- or y- derivatives.
There is also the special value `ksize = FILTER_SCHARR (-1)` that corresponds to the \f$3\times3\f$ Scharr
filter that may give more accurate results than the \f$3\times3\f$ Sobel. The Scharr aperture is
\f[\vecthreethree{-3}{0}{3}{-10}{0}{10}{-3}{0}{3}\f]
for the x-derivative, or transposed for the y-derivative.
The function calculates an image derivative by convolving the image with the appropriate kernel:
\f[\texttt{dst} = \frac{\partial^{xorder+yorder} \texttt{src}}{\partial x^{xorder} \partial y^{yorder}}\f]
The Sobel operators combine Gaussian smoothing and differentiation, so the result is more or less
resistant to the noise. Most often, the function is called with ( xorder = 1, yorder = 0, ksize = 3)
or ( xorder = 0, yorder = 1, ksize = 3) to calculate the first x- or y- image derivative. The first
case corresponds to a kernel of:
\f[\vecthreethree{-1}{0}{1}{-2}{0}{2}{-1}{0}{1}\f]
The second case corresponds to a kernel of:
\f[\vecthreethree{-1}{-2}{-1}{0}{0}{0}{1}{2}{1}\f]
@note First returned matrix correspons to dx derivative while the second one to dy.
@note Rounding to nearest even is procedeed if hardware supports it, if not - to nearest.
@note Function textual ID is "org.opencv.imgproc.filters.sobelxy"
@param src input image.
@param ddepth output image depth, see @ref filter_depths "combinations"; in the case of
8-bit input images it will result in truncated derivatives.
@param order order of the derivatives.
@param ksize size of the extended Sobel kernel; it must be odd.
@param scale optional scale factor for the computed derivative values; by default, no scaling is
applied (see cv::getDerivKernels for details).
@param delta optional delta value that is added to the results prior to storing them in dst.
@param borderType pixel extrapolation method, see cv::BorderTypes
@param borderValue border value in case of constant border type
@sa filter2D, gaussianBlur, cartToPolar
*/
GAPI_EXPORTS std::tuple<GMat, GMat> SobelXY(const GMat& src, int ddepth, int order, int ksize = 3,
double scale = 1, double delta = 0,
int borderType = BORDER_DEFAULT,
const Scalar& borderValue = Scalar(0));
/** @brief Finds edges in an image using the Canny algorithm.
The function finds edges in the input image and marks them in the output map edges using the