message: Python/showpointcloud: Documentation
  Added pointcloud information for python example of showing point cloud.
diff: @@ -16,4 +16,53 @@ If NumPy library is not found you should install it using pip:
  pip install numpy
  ```
  +#### Creating and showing the point cloud
  +
  +* Initilize the system and adiToF camera;
  +* Enable noise reduction;
  +* Get the camera intrinsic parameters;
  +* Initialize *o3d.camera.PinholeCameraIntrinsic* with the intrisic parameters:
  +```console
  +cameraIntrinsics = o3d.camera.PinholeCameraIntrinsic(width, height, fx, fy, cx, cy) fx, fy, cx, cy);
  +```
  +* Create and initialize open3D visualizer:
  +```console
  +vis = o3d.visualization.Visualizer()
  +vis.create_window("PointCloud", 1600, 1600)
  +```
  +* Create the generic point cloud:
  +```console
  +point_cloud = o3d.geometry.PointCloud()
  +```
  +* Request frame from adiToF camera;
  +* Color the depth image with a rainbow spectrum;
  +* Combine IR image and the depth image to get the color image;
  +* Transform the 16bits depth image (the depth image raw) into Open3D *o3d.geometry.Image* type:
  +```console
  + depth16bits_raw = o3d.geometry.Image(depth16bits_map)
  +```
  +* Transform the color image into Open3D *o3d.geometry.Image* type:
  +```console
  + color_raw = o3d.geometry.Image(img_color)
  +```
  +* Create *o3d.geometry.RGBDImage* from depth and color images:
  +```console
  +rgbd_image = o3d.geometry.RGBDImage.create_from_color_and_depth(color_raw, depth16bits_raw, 1000.0, 3.0, False)
  +```
  +* Create the point cloud from the *o3d.geometry.RGBDImage* based on the intrisic parameters:
  +```console
  +pcd = o3d.geometry.PointCloud.create_from_rgbd_image(rgbd_image, cameraIntrinsics)
  +```
  +* Show in the visualizer the point cloud created:
  +```console
  +point_cloud.points = pcd.points
  +point_cloud.colors = pcd.colors
  +if first_time_render_pc:
  + vis.add_geometry(point_cloud)
  + first_time_render_pc = 0
  +vis.update_geometry()
  +vis.poll_events()
  +vis.update_renderer()
  +```
  +#### Point cloud example
  ![Display Image](/doc/img/pointcloud_python.png)
  