A sampling design of local stereology is combined with a method from digital stereology to yield a novel estimator of surface area based on counts of configurations observed in a digitization of an isotropic 2-dimensional slice with thickness $s$. The method is based on a result in (Kiderlen M, Rataj J (2006). On infinitesimal increase of volumes of morphological transforms. Mathematica 53: 103--127) which is generalized in this paper. The proposed surface area estimator is asymptotically unbiased in the case of sets contained in the ball centred at the origin with radius $s$ and in the case of balls centred at the origin with unknown radius. For general shapes bounds for the asymptotic expected relative worst case error are given. A simulation example is discussed for surface area estimation based on $2\times 2\times 2$-configurations.

Keywords: Configurations, digital stereology, local stereology, surface area