Merge pull request #2396 from cudawarped:fix_python_cudawarping_cudaarithm

Add python bindings to cudaobjdetect, cudawarping and cudaarithm

* Overload cudawarping functions to generate correct python bindings.
Add python wrapper to convolution funciton.

* Added shift and hog.

* Moved cuda python tests to this repo and added python bindings to SURF.

* Fix SURF documentation and allow meanshiftsegmention to create GpuMat internaly if not passed for python bindings consistency.

* Add correct cuda SURF test case.

* Fix python mog and mog2 python bindings, add tests and  correct cudawarping documentation.

* Updated KeyPoints in cuda::ORB::Convert python wrapper to be an output argument.

* Add changes suggested by alalek

* Added changes suggested by asmorkalov

modules/cudacodec/misc/python/test/test_cudacodec.py

@@ -0,0 +1,55 @@
+#!/usr/bin/env python
+import os
+import cv2 as cv
+import numpy as np
+
+from tests_common import NewOpenCVTests, unittest
+
+class cudacodec_test(NewOpenCVTests):
+    def setUp(self):
+        super(cudacodec_test, self).setUp()
+        if not cv.cuda.getCudaEnabledDeviceCount():
+            self.skipTest("No CUDA-capable device is detected")
+
+    @unittest.skipIf('OPENCV_TEST_DATA_PATH' not in os.environ,
+                     "OPENCV_TEST_DATA_PATH is not defined")
+    def test_reader(self):
+        #Test the functionality but not the results of the video reader
+
+        vid_path = os.environ['OPENCV_TEST_DATA_PATH'] + '/cv/video/1920x1080.avi'
+        try:
+            reader = cv.cudacodec.createVideoReader(vid_path)
+            ret, gpu_mat = reader.nextFrame()
+            self.assertTrue(ret)
+            self.assertTrue('GpuMat' in str(type(gpu_mat)), msg=type(gpu_mat))
+            #TODO: print(cv.utils.dumpInputArray(gpu_mat)) # - no support for GpuMat
+
+            # not checking output, therefore sepearate tests for different signatures is unecessary
+            ret, _gpu_mat2 = reader.nextFrame(gpu_mat)
+            #TODO: self.assertTrue(gpu_mat == gpu_mat2)
+            self.assertTrue(ret)
+        except cv.error as e:
+            notSupported = (e.code == cv.Error.StsNotImplemented or e.code == cv.Error.StsUnsupportedFormat or e.code == cv.Error.GPU_API_CALL_ERROR)
+            self.assertTrue(notSupported)
+            if e.code == cv.Error.StsNotImplemented:
+                self.skipTest("NVCUVID is not installed")
+            elif e.code == cv.Error.StsUnsupportedFormat:
+                self.skipTest("GPU hardware video decoder missing or video format not supported")
+            elif e.code == cv.Error.GPU_API_CALL_ERRROR:
+                self.skipTest("GPU hardware video decoder is missing")
+            else:
+                self.skipTest(e.err)
+
+    def test_writer_existence(self):
+        #Test at least the existence of wrapped functions for now
+
+        try:
+            _writer = cv.cudacodec.createVideoWriter("tmp", (128, 128), 30)
+        except cv.error as e:
+            self.assertEqual(e.code, cv.Error.StsNotImplemented)
+            self.skipTest("NVCUVENC is not installed")
+
+        self.assertTrue(True) #It is sufficient that no exceptions have been there
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()