warning: setUpNet DNN module was not built with CUDA backend； switching to CPU

warning: setUpNet DNN module was not built with CUDA backend; switching to CPU

解决办法：如果通过cmake安装opencv，请删除配置文件中低于 7 的CUDA_Arch_Bin版本，然后重新构建/重新安装opencv。
注意：如果您使用pip / sudo apt install安装opencv，请使用cmake代替cuda。

参考链接