Methods and systems for ascertaining the roughness of a print media surface are described. Upon depression of a key instructing individual setting, ID information including the user ID and apparatus ID is transmitted to a computer terminal which stores a plurality of user ID’s and setting information corresponding to the apparatus. Linear minimal convolution is used to facilitate the cost function propagation. The hand wheel is connected to the first shaft such that the hand wheel and the first shaft drive one another. Between two successive procedures of identification, the mobile terminal performs a series of procedures of measurement whose duration is fixed so that the total duration for performing a procedure of identification and the subsequent series of procedures of measurement is less than 25 seconds.