1. A method for estimating parameter values comprising: obtaining image data with an imaging apparatus; fitting a parameterized model function from the image data; generating a N-dimensional grid, wherein N is a number of one or more terms that are non-linear in a parameter of the derived model function; pre-calculating the one or more non-linear terms given the parameter model function and the designated values of the non-linear parameters; calculating one or more remaining model terms of the parameter model function; and displaying at least one of the one or more non-linear and remaining linear model terms.