Fix YOLOv8 C++ ONNXRuntime transpose op (#15779)

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

examples/YOLOv8-ONNXRuntime-CPP/inference.cpp

@@ -221,8 +221,8 @@ char* YOLO_V8::TensorProcess(clock_t& starttime_1, cv::Mat& iImg, N& blob, std::
     case YOLO_DETECT_V8:
     case YOLO_DETECT_V8_HALF:
     {
-        int strideNum = outputNodeDims[1];//8400
+        int signalResultNum = outputNodeDims[1];//84
-        int signalResultNum = outputNodeDims[2];//84
+        int strideNum = outputNodeDims[2];//8400
         std::vector<int> class_ids;
         std::vector<float> confidences;
         std::vector<cv::Rect> boxes;
@@ -230,18 +230,18 @@ char* YOLO_V8::TensorProcess(clock_t& starttime_1, cv::Mat& iImg, N& blob, std::
         if (modelType == YOLO_DETECT_V8)
         {
             // FP32
-            rawData = cv::Mat(strideNum, signalResultNum, CV_32F, output);
+            rawData = cv::Mat(signalResultNum, strideNum, CV_32F, output);
         }
         else
         {
             // FP16
-            rawData = cv::Mat(strideNum, signalResultNum, CV_16F, output);
+            rawData = cv::Mat(signalResultNum, strideNum, CV_16F, output);
             rawData.convertTo(rawData, CV_32F);
         }
         //Note:
         //ultralytics add transpose operator to the output of yolov8 model.which make yolov8/v5/v7 has same shape
         //https://github.com/ultralytics/assets/releases/download/v8.2.0/yolov8n.pt
-        //rowData = rowData.t();
+        rawData = rawData.t();
 
         float* data = (float*)rawData.data;