Merge pull request #20175 from rogday:dnn_samples_cuda

add cuda and vulkan backends to dnn samples

samples/dnn/classification.cpp

@@ -22,12 +22,17 @@ std::string keys =
                             "0: automatically (by default), "
                             "1: Halide language (http://halide-lang.org/), "
                             "2: Intel's Deep Learning Inference Engine (https://software.intel.com/openvino-toolkit), "
-                            "3: OpenCV implementation }"
+                            "3: OpenCV implementation, "
+                            "4: VKCOM, "
+                            "5: CUDA },"
     "{ target           | 0 | Choose one of target computation devices: "
                             "0: CPU target (by default), "
                             "1: OpenCL, "
                             "2: OpenCL fp16 (half-float precision), "
-                            "3: VPU }";
+                            "3: VPU, "
+                            "4: Vulkan, "
+                            "6: CUDA, "
+                            "7: CUDA fp16 (half-float preprocess) }";
 
 using namespace cv;
 using namespace dnn;