The notion of group invariance helps neural networks in recognizing patterns and features under geometric transformations. Indeed, it has been shown that group invariance can largely improve deep learning performances in practice, where such transformations are very common. This research studies affine invariance on continuous-domain convolutional neural networks. Despite other research considering isometric invariance or similarity invariance, we focus on the full structure of affine transforms generated by the generalized linear group $\mathrm{GL}_2(\mathbb{R})$. We introduce a new criterion to assess the similarity of two input signals under affine transformations. Then, unlike conventional methods that involve solving complex optimization problems on the Lie group $G_2$, we analyze the convolution of lifted signals and compute the corresponding integration over $G_2$. In sum, our research could eventually extend the scope of geometrical transformations that practical deep-learning pipelines can handle.

本研究探讨连续域卷积神经网络中的仿射不变性，并引入一种新准则评估仿射变换下两个输入信号的相似性。通过分析抬升信号的卷积并计算相应的广义线性群 $G_2$ 上的积分，与解决复杂优化问题的传统方法不同，本研究为实际深度学习流程处理几何变换的范围提供了扩展。