ResNet models • A new Layer-wise Relevance Propagation (LRP) rule to handle residual connections of ResNet • 𝑪𝟑-LRP that selects the most noteworthy area based on the generated relevance regions. We introduce : LRP [Bach+, PLoS15] GradCAM [Selvaraju+, ICCV17] Ours
methods GradCAM [Selvaraju+, ICCV17] Gradients flowing to produce a coarse localization map. Input x Gradient [Shrikumar+, ICLR18] Multiplying the input image by the gradient of the output. LRP [Bach+, PLoS15] Propagating the prediction backward through the network layers.
an established theoretical framework LRP [Bach+, PloS15] n Layer-wise Relevance Propagation [Bach+, PLoS15] n Established theoretical framework n Transparent computational processes
at layer 𝑙 + 1 : activation of neuron 𝑘 : weight of the connection between neuron 𝑖 and neuron 𝑘 Related work : Layer-Wise Relevance Propagation - an established theoretical framework LRP [Bach+, PloS15]
at layer 𝑙 + 1 : activation of neuron 𝑘 : weight of the connection between neuron 𝑖 and neuron 𝑘 Related work : Layer-Wise Relevance Propagation - an established theoretical framework LRP [Bach+, PloS15] A rule must be defined for each type of layer
Output of the Bottleneck block 𝐶 : Output channels 𝑈 : Height 𝑉 : Width : Avoiding a zero division IDEA : Considering each bottleneck block as a single dense layer : Relevance of the layer L Proposed Method : Relevance backpropagation for Bottleneck layers
information Relevance map (LRP output) Proposed Method : Choice Contour Component : 𝑪𝟑 1st Contour (findContours) 1st Component (connectedComponents) C1C [Iida+, SIG-AM23] AND Final Relevance map Only the pixels from BOTH the 1st contour and the 1st component are kept TRUE
the most insightful explanations § Only one wing is attended § The attended area is vague Original ABN [Fukui+, CVPR19] LRP [Bach+, PloS15] GradCAM [Selvaraju+, ICCV17] RISE [Petsuik+, BMVC18]
the most insightful explanations § The bird is correctly attended § The attended area is vague Original ABN [Fukui+, CVPR19] LRP [Bach+, PloS15] GradCAM [Selvaraju+, ICCV17] RISE [Petsuik+, BMVC18]
the most insightful explanations § Almost no pixel is attended § Not an insightful explanation Original ABN [Fukui+, CVPR19] LRP [Bach+, PloS15] GradCAM [Selvaraju+, ICCV17] RISE [Petsuik+, BMVC18]
the most insightful explanations § The bird is correctly attended § The background is also attended Original ABN [Fukui+, CVPR19] LRP [Bach+, PloS15] GradCAM [Selvaraju+, ICCV17] RISE [Petsuik+, BMVC18]
the most insightful explanations § The bird is correctly attended § The shape of the bird’s body is precisely attended Original ABN [Fukui+, CVPR19] LRP [Bach+, PloS15] GradCAM [Selvaraju+, ICCV17] RISE [Petsuik+, BMVC18]
explanations Contributions: • A method for calculating LRP in models with residual connections • 𝐶!-LRP, which improves the quality of explanations 𝑪𝟑-LRP LRP [Bach+, PloS15] output 𝐶!-LRP output
the different methods failed to generate an insightful explanation Original Ours ABN [Fukui 19] LRP [Bach 15] GradCAM [Selvaraju 18] RISE [Petsuik 18] ⇒ None of the different methods correctly attend the bird
focusing on an insufficient part of the image Error Type IA OA WA #Error 63 21 16 Insufficiently Attended (IA) Over-Attended (OA) Wrongly-Attended (WA) • IA : The area of attention is too small. • OA : The area of relevance is excessively large • WA : The relevance is given to pixels that do not directly contribute to the classification.