更快的RCNN，为什么conv的结果可以成为bbox_deltas？

Question

Here和here 是代码。

我很困惑rpn_bbox_pred只是卷积的结果。

rpn_bbox_pred正在成为bbox_deltas。

我无法理解这一点。

Answer 1

Suppose we have a (3,2,36) conv's result.

Note that:

36 = 4 * 9

So after reshape, each point of (3,2) have 9 proposal.

As the program shows:

import numpy as np
a = [[[1]*36,[2]*36],[[3]*36,[4]*36],[[5]*36,[6]*36]]
a = np.array(a)
print(a.reshape([-1,4]))

In the program, every (3,2) feature map is [[1,2],[3,4],[5,6]].

The print result:

[[1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [2 2 2 2]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [3 3 3 3]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [4 4 4 4]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [5 5 5 5]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]
 [6 6 6 6]]