Created by: AN-ZE

在operators.py新增padding算子,将图片扩展到固定尺寸中，训练不能运行，停止不动

  @register_op
  class PaddingImage(BaseOperator):
      def __init__(self, pad=1280, mean=[127.5, 127.5, 127.5]):
          super(PaddingImage, self).__init__()
          self.pad = pad
          self.mean = mean

    def __call__(self, sample, context):
        assert 'image' in sample, 'not found image data'
        im = sample['image']
        gt_bbox = sample['gt_bbox']
        gt_class = sample['gt_class']
        im_width = sample['w']
        im_height = sample['h']
        if self.pad >= 0:
            height = int(self.pad)
            width = int(self.pad)
            h_off = math.floor(np.random.uniform(0, height - im_height))
            w_off = math.floor(np.random.uniform(0, width - im_width))
            expand_bbox = [
                -w_off / im_width, -h_off / im_height,
                (width - w_off) / im_width, (height - h_off) / im_height
            ]
            expand_im = np.ones((height, width, 3))
            expand_im = np.uint8(expand_im * np.squeeze(self.mean))
            expand_im = Image.fromarray(expand_im)
            im = Image.fromarray(im)
            expand_im.paste(im, (int(w_off), int(h_off)))
            expand_im = np.asarray(expand_im)
            gt_bbox, gt_class, _ = filter_and_process(expand_bbox, gt_bbox,
                                                      gt_class)
            sample['image'] = expand_im
            sample['gt_bbox'] = gt_bbox
            sample['gt_class'] = gt_class
            sample['w'] = width
            sample['h'] = height

        return sample