A method is disclosed for estimating an affine relation between a first image and a second image. The method then generates a reset signal based on the first signal and the second signal. Gate oxides formed from elements such as yttrium and gadolinium are thermodynamically stable such that the gate oxides formed will have minimal reactions with a silicon substrate or other structures during any later high temperature processing stages. In one design, a user entity determines a plurality of groups of cells to make measurements. The feature values are combined to form a feature value tuple for the food item. The color filter has two narrow band color filters and one wide band filter.