A method is provided for determining an actual profile of an object printed on a substrate. The method can include receiving an actual spectrum signal associated with the object, selecting a first model profile, and generating a first model spectrum signal associated with the first model profile. The method can further include comparing the first model spectrum signal with the actual spectrum signal. If the first model spectrum signal and the actual spectrum signal do not match a desired tolerance, the aforementioned selecting, generating, and comparing can be repeated with a second model profile. The second model profile can be selected based on the first model spectrum signal having undergone an optimization process based on a number of variable parameters of the first model profile, where the number of variable parameters is reduced by approximating the first model profile to a single shape with a reduced number of variable parameters.