Flipdim(X, dim) function is a function used for matrix inversion transformation in matlab, where x represents a matrix, dim specifies the inversion method, dim is 1, which means that each column is arranged in reverse order, and 2 means that each row is arranged in reverse order. In addition, matlab also provides functions that can be directly used for left and right, up and down and 90-degree rotation, as follows: left and right flip: fliplr(x) flip up and down: flipud(x) rotate 90 degrees: rot90(x) In matlab, you can enter helpflipdim in the command window to get help information.