The original efficient implementation of ELAS uses SIMDaccelerators with fixed widths of 16 bytes for feature extractionand matching. Such an implementation, however, lacks flexibil-ity since the number of pixels it can process is limited and mustbe in multiples of 16 (for 8 bit pixels). The result is that for a given W×W window, only a subset of pixels contained withinit are used for matching purposes.