Processing 32FC1 image by pixel, convert it to uint8 array and put data in to ROS sensor_msgs/Image

32FC1_depth_image_to_uint8.cpp

sensor_msgs::Image depth_image;
std::vector<uint8_t> depth_image_vector;
int32_t width = 320; // width example
int32_t height = 240; // height example
float* depth_data; //original data

depth_image.step = 4*width; // one pixel data size of 32FC1 is 4 bytes;

for (int count=0; count < width * height; count++)
{
  float depth_pixel = depth_data[count];
  // add process here
  uint8_t *depth_pixel_array = reinterpret_cast<uint8_t *>(&depth_pixel);
  std::vector<uint8_t> depth_pixel_vector (depth_pixel_array, depth_pixel_array + 4);
  depth_image_vector.insert(depth_image_vector.end(), depth_pixel_vector.begin(), depth_pixel_vector.end());
}
depth_image.data.clear();
depth_image.data = depth_image_vector;