chainer.functions.roi_pooling_2d

chainer.functions.roi_pooling_2d(x, rois, outh, outw, spatial_scale)[source]

Spatial Region of Interest (ROI) pooling function.

This function acts similarly to MaxPooling2D, but it computes the maximum of input spatial patch for each channel with the region of interest.

Parameters:
  • x (Variable) – Input variable. The shape is expected to be 4 dimentional: (n: batch, c: channel, h, height, w: width).
  • rois (Variable) – Input roi variable. The shape is expected to be (n: data size, 5), and each datum is set as below: (batch_index, x_min, y_min, x_max, y_max).
  • outh (int) – Height of output image after pooled.
  • outw (int) – Width of output image after pooled.
  • spatial_scale (float) – Scale of the roi is resized.
Returns:

Output variable.
Return type:

Variable

See the original paper proposing ROIPooling: Fast R-CNN.