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1. Remove unnecessary barriers.
2. Adjust CTA_SIZE based on the following cases for Intel platform:
   a) OCL_Photo_DenoisingGrayscale.DenoisingGrayscale
   b) OCL_Photo_DenoisingColored.DenoisingColored

Avoid stack overflow based on std::vector cause
std::vector::resize() segmentation fault.

This line causes the following error when building custom projects that use OpenCV beta 3:
ld: warning: directory not found for option '-L/<project_root>/-Wl,/usr/local/cuda'

OpenCV 3.0.0 Beta

Sample works with OpenNI2 with minimal code changes (CAP_OPENNI -> CAP_OPENNI2)

Not all parameters are specified for openni::VideoMode, so
"selected" mode can be unsupported for device.
Replace default VideoMode constructor to result of getVideoMode() call.

fixed my_umat(roi).clone() test by disabling poorly aligned ROI's. Real fix of the problem will require a separate branch in UMat::copyTo().

Avoid phi exceed PI/2 to get the negative value of cos(phi).