A method of neural network operations by using a grid generator is provided for converting modes according to classes of areas to satisfy level 4 of autonomous vehicles. The method includes steps of: (a) a computing device instructing a pair detector to acquire information on locations and classes of pairs for testing by detecting the pairs for testing; (b) the computing device instructing the grid generator to generate section information by referring to the information on the locations of the pairs for testing; (c) the computing device instructing a neural network to determine parameters for testing by referring to parameters for training which have been learned by using information on pairs for training; and (d) the computing device instructing the neural network to apply the neural network operations to a test image by using each of the parameters for testing to thereby generate one or more neural network outputs.