如何获得暹罗网络的CAM（类激活图）？

Question

如何为暹罗网络获取CAM（类激活图）？ 像这样的暹罗网络：

class BiDateNet(nn.Module):
    def __init__(self, n_channels, n_classes):
        super(BiDateNet, self).__init__()
        self.inc = inconv(n_channels, 64)
        self.down = down()
        self.up = up()
        self.outc = outconv(64, n_classes)
    def forward(self, x_d1, x_d2):
        x1_d1 = self.inc(x_d1)
        x2_d1 = self.down(x1_d1)

        x1_d2 = self.inc(x_d2)
        x2_d2 = self.down(x1_d2)

        x = self.up(,)
        x = self.outc(x)
        return x

请提供一些代码。