A substrate having a coding pattern disposed on a surface thereof. The coding pattern comprises a plurality of target elements defining a target grid. The target grid comprises a plurality of cells, wherein neighboring cells share target elements. A plurality of data elements are contained in each cell. Tags are defined by a plurality of contiguous cells and each tag comprises respective local tag data encoded by a respective set of the data elements. The data elements encode data values by pulse position modulation, which facilitates low-pass filtering during image processing.