picamera+overlay

snippet.py

for foo in camera.capture_continuous(stream,
                                     format='rgb',
                                     use_video_port=True):
  # Make Image object from camera stream
  stream.truncate()
  stream.seek(0)
  input = np.frombuffer(stream.getvalue(), dtype=np.uint8)
  input = input.reshape((CAMERA_HEIGHT, CAMERA_WIDTH, 3))
  image = Image.fromarray(input)
  # image.save("out.jpg")

  # Make overlay image plane
  img = Image.new('RGBA',
                  (CAMERA_WIDTH, CAMERA_HEIGHT),
                  (255, 0, 0, 0))
  draw = ImageDraw.Draw(img)

  # Run detection
  start_ms = time.time()
  results = engine.DetectWithImage(image,
                                   threshold=0.2, top_k=10)
  elapsed_ms = (time.time() - start_ms)*1000.0
  if results:
    for obj in results:
      box = obj.bounding_box.flatten().tolist()
      box[0] *= CAMERA_WIDTH
      box[1] *= CAMERA_HEIGHT
      box[2] *= CAMERA_WIDTH
      box[3] *= CAMERA_HEIGHT
      # print(box)
      # print(labels[obj.label_id])
      draw.rectangle(box, outline='red')
      draw.text((box[0], box[1]-10), labels[obj.label_id],
                font=fnt, fill="red")
    camera.annotate_text = "{0:.2f}ms".format(elapsed_ms)
  if not overlay_renderer:
    overlay_renderer = camera.add_overlay(
      img.tobytes(),
      size=(CAMERA_WIDTH, CAMERA_HEIGHT), layer=4, alpha=255)
  else:
    overlay_renderer.update(img.tobytes())