Candidate layout patterns can be assessed using a sparse pattern dictionary of known design layout patterns by determining sparse coefficients for each candidate pattern, reconstructing the respective candidate pattern, and determining reconstruction error. Any pattern with reconstruction error over a threshold value can be flagged. Compressive sampling can be employed, such as by projecting each candidate pattern onto a random line or a random matrix. The dictionary can be built by determining sparse coefficients of known patterns and respective basis function sets using matching pursuit, variants of SVD, and/or other techniques.