二维卷积运算之C语言实现 若x为N1*M1的二维信号，y为N2*M2的二维信号，则卷积为(N1+N2-1)*(M1+M2-1)的信号-2D convolution operators on C language if x N1 * M1 to the two-dimensional signal y * M2 N2 for the two-dimensional signal, convolution (N1 N2-1) * (M1 M2 - 1) signal