A method, on a computing device, for determining whether a mark is genuine, the method comprising: receiving an image of a candidate mark; using the received image, measuring a characteristic of an edge of the candidate mark, wherein measuring the characteristic of the edge of the candidate mark comprises calculating a plurality of projected average pixel values in a portion of the candidate mark that includes the edge, wherein respective projected average pixel values, among the plurality of projected average values, are calculated by averaging pixel values along respective lines (710, 712, 714, 716) starting from an interior of the portion of the candidate mark and extending out beyond the edge of the candidate mark; creating a profile for the edge of the candidate mark based on the plurality of projected average pixel values calculated in the portion of the candidate mark; creating a first filtered profile for the edge by filtering, from the profile of the edge, all spatial frequency components except for those in a first spatial frequency band; creating a second filtered profile for the edge by filtering, from the profile of the edge, all spatial frequency components except for those in a second spatial frequency band; wherein the first spatial frequency band contains a first range of spatial frequencies and the second spatial frequency band contains a second range of spatial frequencies, and wherein the second range of spatial frequencies is different from the first range of spatial frequencies; comparing the first filtered profile of the edge with an equivalent first filtered profile of an edge of a genuine mark; comparing the second filtered profile of the edge with an equivalent second filtered profile of an edge of the genuine mark; determining whether the candidate mark is genuine based on the first filtered profile comparison and the second filtered profile comparison; and indicating a result of the determination to a user. receiving an image of a candidate mark; using the received image, measuring a characteristic of an edge of the candidate mark, wherein measuring the characteristic of the edge of the candidate mark comprises calculating a plurality of projected average pixel values in a portion of the candidate mark that includes the edge, wherein respective projected average pixel values, among the plurality of projected average values, are calculated by averaging pixel values along respective lines (710, 712, 714, 716) starting from an interior of the portion of the candidate mark and extending out beyond the edge of the candidate mark; creating a profile for the edge of the candidate mark based on the plurality of projected average pixel values calculated in the portion of the candidate mark; creating a first filtered profile for the edge by filtering, from the profile of the edge, all spatial frequency components except for those in a first spatial frequency band; creating a second filtered profile for the edge by filtering, from the profile of the edge, all spatial frequency components except for those in a second spatial frequency band; wherein the first spatial frequency band contains a first range of spatial frequencies and the second spatial frequency band contains a second range of spatial frequencies, and wherein the second range of spatial frequencies is different from the first range of spatial frequencies; comparing the first filtered profile of the edge with an equivalent first filtered profile of an edge of a genuine mark; comparing the second filtered profile of the edge with an equivalent second filtered profile of an edge of the genuine mark; determining whether the candidate mark is genuine based on the first filtered profile comparison and the second filtered profile comparison; and indicating a result of the determination to a user.