【OPENVX】快速角点提取之 vxuFastCorners

• openvx_utils.h

  #ifndef OPENVX_UTILS_H
  #define OPENVX_UTILS_H
  #include 
  #include 
  #include 
  #include "VX/vx.h"
  
  // 状态检查
  #define ERROR_CHECK_STATUS(status)                                                              \
      {                                                                                           \
          vx_status status_ = (status);                                                           \
          if (status_ != VX_SUCCESS)                                                              \
          {                                                                                       \
              printf("ERROR: failed with status = (%d) at " __FILE__ "#%d\n", status_, __LINE__); \
              exit(1);                                                                            \
          }                                                                                       \
      }
  
  // 对象创建检查
  #define ERROR_CHECK_OBJECT(obj, message)                                                        \
      {                                                                                           \
          vx_status status_ = vxGetStatus((vx_reference)(obj));                                   \
          if (status_ != VX_SUCCESS)                                                              \
          {                                                                                       \
              printf("ERROR: failed with status = (%d) at " __FILE__ "#%d\n", status_, __LINE__); \
              puts(message);                                                                      \
              exit(1);                                                                            \
          }                                                                                       \
      }
  
  // 函数名称
  #ifdef DEBUG
  #define DEBUG_FUNCTION_NAME(void)                                                     \
      {                                                                                 \
          printf("================================================================\n"); \
          printf(__func__);                                                             \
          printf("\n");                                                                 \
      }
  
  #define DEBUG_LOG(format, ...)                                                      \
      {                                                                               \
          printf("[%s:%d->%s] " format, __FILE__, __LINE__, __func__, ##__VA_ARGS__); \
      }
  #else
  #define DEBUG_FUNCTION_NAME(void)
  #define DEBUG_LOG(format, ...)
  #endif
  
  static inline vx_image vxCvMatToVxImage(const vx_context context, const cv::Mat &cv_image)
  {
      DEBUG_FUNCTION_NAME();
  
      // 图像类型
      vx_df_image vx_image_type;
      switch (cv_image.type())
      {
      case CV_8UC1:
          vx_image_type = VX_DF_IMAGE_U8;
          break;
      case CV_8UC3:
          vx_image_type = VX_DF_IMAGE_RGB;
          break;
      default:
          DEBUG_LOG("Format %d not supported\n", vx_image_type);
  
          return NULL;
      }
  
      // 图像属性
      int width = cv_image.cols;
      int height = cv_image.rows;
  
      // 创建图像
      vx_image image = vxCreateImage(context, width, height, vx_image_type);
  
      // 区域
      vx_rectangle_t patch;
      patch.start_x = 0;
      patch.start_y = 0;
      patch.end_x = width;
      patch.end_y = height;
  
      vx_map_id map_id;
      vx_imagepatch_addressing_t addr;
      unsigned char *ptr;
      vx_status status = vxMapImagePatch(image, &patch, 0, &map_id, &addr, (void **)&ptr, VX_WRITE_ONLY, VX_MEMORY_TYPE_HOST, VX_NOGAP_X);
      if (status != VX_SUCCESS)
      {
          DEBUG_LOG("vxMapImagePatch returned error with code %d\n", status);
          return NULL;
      }
  
      if (addr.stride_x != 1 && addr.stride_x != 3)
      {
          DEBUG_LOG("addressing structure not supported, stride_x = %d\n", addr.stride_x);
          return NULL;
      }
  
      for (int y = 0; y < height; y++)
      {
          unsigned char *ptr_y = ptr + y * addr.stride_y;
          memcpy(ptr_y, cv_image.ptr(y), addr.stride_y);
      }
  
      status = vxUnmapImagePatch(image, map_id);
      if (status != VX_SUCCESS)
      {
          DEBUG_LOG("vxUnmapImagePatch failed...\n");
          return NULL;
      }
  
      return image;
  }
  
  static inline int vxVxImageToCvMat(const vx_image image, cv::Mat &cv_image)
  {
      DEBUG_FUNCTION_NAME();
  
      // 图像属性
      vx_uint32 width = 0;
      vx_uint32 height = 0;
      ERROR_CHECK_STATUS(vxQueryImage(image, VX_IMAGE_WIDTH, &width, sizeof(width)));
      ERROR_CHECK_STATUS(vxQueryImage(image, VX_IMAGE_HEIGHT, &height, sizeof(height)));
  
      // 图像类型
      vx_df_image image_type;
      ERROR_CHECK_STATUS(vxQueryImage(image, VX_IMAGE_FORMAT, &image_type, sizeof(image_type)));
  
      int cv_image_type;
      switch (image_type)
      {
      case VX_DF_IMAGE_U8:
          cv_image_type = CV_8UC1;
          break;
      case VX_DF_IMAGE_RGB:
          cv_image_type = CV_8UC3;
          break;
      default:
          DEBUG_LOG("Format %d not supported\n", cv_image_type);
          return -1;
      }
  
      // 区域
      vx_rectangle_t patch = {0, 0, width, height};
      vx_map_id map_id;
      vx_imagepatch_addressing_t addr;
      unsigned char *ptr;
      vx_status status = vxMapImagePatch(image, &patch, 0, &map_id, &addr, (void **)&ptr, VX_READ_ONLY, VX_MEMORY_TYPE_HOST, VX_NOGAP_X);
      if (status != VX_SUCCESS)
      {
          DEBUG_LOG("vxMapImagePatch returned error with code %d\n", status);
          return -1;
      }
  
      if (addr.stride_x != 1 && addr.stride_x != 3)
      {
          DEBUG_LOG("addressing structure not supported, stride_x = %d\n", addr.stride_x);
          return -1;
      }
  
      cv_image = cv::Mat(height, width, cv_image_type);
      for (int y = 0; y < height; y++)
      {
          unsigned char *ptr_y = ptr + y * addr.stride_y;
          memcpy(cv_image.ptr(y), ptr_y, addr.stride_y);
      }
  
      status = vxUnmapImagePatch(image, map_id);
      if (status != VX_SUCCESS)
      {
          DEBUG_LOG("vxUnmapImagePatch failed...\n");
          return -1;
      }
  
      return 0;
  }
  
  static inline vx_image ReadImage(vx_context context, const char *file_name)
  {
      cv::Mat mat = cv::imread(file_name, cv::IMREAD_ANYCOLOR);
      return vxCvMatToVxImage(context, mat);
  }
  
  static inline void SaveImage(vx_image image, const char *file_name)
  {
      cv::Mat mat;
      int ret = vxVxImageToCvMat(image, mat);
      if (!ret)
          cv::imwrite(file_name, mat);
  }
  
  static inline void DisplayImage(vx_image image, const char *window_name, int time = 0, int width = 640, int height = 480)
  {
      cv::Mat mat;
      int ret = vxVxImageToCvMat(image, mat);
      if (!ret)
      {
          cv::namedWindow(window_name, cv::WINDOW_NORMAL);
          cv::resizeWindow(window_name, width, 480);
          cv::imshow(window_name, mat);
          cv::waitKey(time);
      }
  }
  
  static inline void DisplayImage(cv::Mat &image, const char *window_name, int time = 0, int width = 640, int height = 480)
  {
      cv::namedWindow(window_name, cv::WINDOW_NORMAL);
      cv::resizeWindow(window_name, width, 480);
      cv::imshow(window_name, image);
      cv::waitKey(time);
  }
  
  #endif
  

• openvx_vxu_fast_corner.cpp

  #include 
  #include 
  #include "VX/vx.h"
  #include "VX/vxu.h"
  #include "openvx_utils.h"
  
  /// 目的：
  ///     1. 使用图像创建函数在黑色背景上创建一个白色矩形
  ///     2. 使用Fast Corners算法计算角点数量
  
  void errorCheck(vx_context context, vx_status status, const char *message)
  {
      if (status)
      {
          puts("ERROR! ");
          puts(message);
          vxReleaseContext(&context);
          exit(EXIT_FAILURE);
      }
  }
  
  vx_image makeInputImage(vx_context context)
  {
      DEBUG_FUNCTION_NAME();
  
      /// 创建图像
      vx_image image = vxCreateImage(context, 100U, 100U, VX_DF_IMAGE_U8);
  
      /// 判断图像是否创建成功
      if (VX_SUCCESS != vxGetStatus((vx_reference)image))
          return image;
  
      /// 定义矩形
      vx_rectangle_t rect = {.start_x = 20, .start_y = 40, .end_x = 80, .end_y = 60};
  
      /// 创建感兴趣区域
      vx_image roi = vxCreateImageFromROI(image, &rect);
      if(VX_SUCCESS != vxGetStatus((vx_reference)roi))
          return roi;
  
      vx_pixel_value_t pixel_white, pixel_black;
      pixel_white.U8 = 255;
      pixel_black.U8 = 0;
      
      /// 设置背景像素
      if ( VX_SUCCESS != vxSetImagePixelValues(image, &pixel_black))
          vxReleaseImage(&image);
      
      /// 设置前景像素
      if (VX_SUCCESS != vxSetImagePixelValues(roi, &pixel_white))
          vxReleaseImage(&roi);
  
      return image;
  }
  
  void fastCorner(vx_context context, vx_image image, vx_bool is_use_nonmax_suppression)
  {
      DEBUG_FUNCTION_NAME();
      
      /// 分割阈值
      vx_float32 strength_thresh_value = 128.0f;
      vx_scalar strength_thresh = vxCreateScalar(context, VX_TYPE_FLOAT32, &strength_thresh_value);
      errorCheck(context, vxGetStatus((vx_reference) strength_thresh), "Could not create threshold scalar");
  
      /// 创建用于储存角点结果的数组
      vx_array corners = vxCreateArray(context, VX_TYPE_KEYPOINT, 100);
      errorCheck(context, vxGetStatus((vx_reference) corners), "Could not create corner array");
  
      /// 角点数量
      vx_size num_corners_value = 0;
      vx_scalar num_corners = vxCreateScalar(context, VX_TYPE_SIZE, &num_corners_value);
      errorCheck(context, vxGetStatus((vx_reference) num_corners), "Could not create corner number scalar");
  
      /// 用于显示角点而开辟的内存区
      vx_keypoint_t *kp = (vx_keypoint_t *)calloc(100, sizeof(vx_keypoint_t));
      errorCheck(context, kp == NULL, "Could not calloc memory");
  
      /// 执行角点查找
      vx_status status = vxuFastCorners(context, image, strength_thresh, is_use_nonmax_suppression, corners, num_corners);
      errorCheck(context, status, "Fast Corners function failed");
  
      /// 获取角点数量
      status = vxCopyScalar(num_corners, &num_corners_value, VX_READ_ONLY, VX_MEMORY_TYPE_HOST);
      errorCheck(context, status, "vxCopyScalar failed");
      printf("Found %zu corners %s non-max suppression\n", num_corners_value, is_use_nonmax_suppression ? "with" : "without");
  
      /// 获取角点数据
      status = vxCopyArrayRange(corners, 0, num_corners_value, sizeof(vx_keypoint_t), kp, VX_READ_ONLY, VX_MEMORY_TYPE_HOST);
      errorCheck(context, status, "vxCopyArrayRange failed");
  
      for (int i = 0; i < num_corners_value; ++i)
      {
          printf("Entry %3d: x = %d, y = %d\n", i, kp[i].x, kp[i].y);
      }
  
      cv::Mat cv_image;
      int ret = vxVxImageToCvMat(image, cv_image);
      if (0 == ret)
      {
          cv::Mat cv_image_color;
          cv::cvtColor(cv_image, cv_image_color, cv::COLOR_GRAY2BGR);
          for (int i = 0; i < num_corners_value; ++i)
          {
              cv::circle(cv_image_color, cv::Point(kp[i].x, kp[i].y), 3, cv::Scalar(0, 255, 0), -1);
          }
          DisplayImage(cv_image_color, "KeyPoints");
      }
  
      free(kp);
  }
  
  int main(int argc, char *argv[])
  {
      (void) argc;
      (void) argv;
  
      /// 创建上下文
      vx_context context = vxCreateContext();
      errorCheck(context, vxGetStatus((vx_reference)context), "Could not create a vx_context");
  
      /// 创建图像（黑色背景上带有白色矩形）
      vx_image image = makeInputImage(context);
      DisplayImage(image, "image");
      errorCheck(context, vxGetStatus((vx_reference)image), "Could not create image1");
  
      /// 使用非极大值抑制
      fastCorner(context, image, vx_true_e);
  
      /// 不使用非极大值抑制
      fastCorner(context, image, vx_false_e);
  
      vxReleaseContext(&context);
  
      return EXIT_SUCCESS;
  }
  

• 效果