An image processing method includes generating a first augmented image by applying first data augmentation on an input image, generating a second augmented image by applying second data augmentation on the input image, generating a first output by inputting the first augmented image to a neural network, generating a second output by inputting the second augmented image to the neural network, calculating an output difference indicating a degree of difference between the first output and the second output, and updating a weight coefficient of each layer of the neural network based on the output difference.