roi_align¶

dragon.vision.roi_align(
  inputs,
  pooled_h,
  pooled_w,
  spatial_scale=1.0,
  sampling_ratio=- 1,
  aligned=False,
  **kwargs
)[source]¶

Apply the average roi align. [He et.al, 2017].

The input rois should be packed with the shape \((N, 5)\), where \(N\) is the number of RoIs, and each column takes \(5\) values for a sequence of \([i_{\text{batch}}, x_{\min}, y_{\min}, x_{\max}, y_{\max}]\).

Examples:

x = dragon.range(18, dtype='float32').reshape((1, 2, 3, 3))
rois = dragon.constant([[0., 1., 1., 2.]], dtype='float32')
print(dragon.vision.roi_align([x, rois], pooled_h=1, pooled_w=1))

Parameters:

• inputs (Sequence[dragon.Tensor]) – The tensor x and rois.
• pooled_h (int, required) – The output height.
• pooled_w (int, required) – The output width.
• spatial_scale (float, optional, default=1.0) – The input scale to the size of rois.
• sampling_ratio (int, optional, default=-1) – The number of sampling grids for rois.
• aligned (bool, optional, default=False) – Whether to shift the input coordinates by -0.5.

Returns:

dragon.Tensor – The output tensor.