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Grad_cam++的实现和原文的计算公式不一致，请问怎么理解 #35

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zgf6781882 opened this issue Jan 19, 2021 · 3 comments
Open

Grad_cam++的实现和原文的计算公式不一致，请问怎么理解 #35

zgf6781882 opened this issue Jan 19, 2021 · 3 comments

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@zgf6781882
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    norm_factor = np.sum(gradient, axis=(1, 2))  # [C]归一化
    for i in range(len(norm_factor)):
        norm_factor[i] = 1. / norm_factor[i] if norm_factor[i] > 0. else 0.  # 避免除零
    alpha = indicate * norm_factor[:, np.newaxis, np.newaxis]  # [C,H,W]

请问怎么理解alpha的计算啊？
@yizt
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yizt commented Jan 21, 2021

image

@zgf6781882 以上是计算一个通道的alpha过程示例

@zhailei-zl
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您好，这部分alpha的计算中，和原论文公式怎么对应呢，原论文中的alpha计算中分母含有梯度乘特征图并进行求和

@mlerma54
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Hello, this way of computing the alphas will cause all weights to be 1, and does not mach the original paper (eq. 19 in https://arxiv.org/abs/1710.11063). Can you please elaborate? Thank you!

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@mlerma54 @yizt @zgf6781882 @zhailei-zl