A system for non-contact biometric identification of a user, the system comprising: a scanner device comprising: a first infrared light source (206) to produce infrared light that exhibits a first polarization and a second infrared light source (206) to produce infrared light that exhibits a second polarization; a camera with a polarizer that passes light having a first polarization or including a detector that is sensitive to a first polarization of capture light; and a computing device configured to: at a first time, operate the first infrared light source to illuminate a portion of a user with infrared light having the first polarization and operate the camera to acquire first raw image data; at a second time, operate the second infrared light source to illuminate the portion of the user with infrared light having the second polarization and operate the camera to acquire second raw image data; and wherein the system is further configured to: determine a first set of sub-images wherein each sub-image in the first set of sub-images corresponds to a particular area within the first raw image data; determine a first set of feature vectors for one or more of the sub-images in the first set of sub-images; determine a second set of sub-images wherein each sub-image in the second set of sub-images corresponds to a particular area within the second raw image data; determine a second set of feature vectors for one or more of the sub-images in the second set of sub-images; determine, based on the first set of feature vectors and the second set of feature vectors, one or more current signatures; and determine a user identifier based on comparison of the one or more current signatures with one or more previously stored reference signatures. a scanner device comprising: a first infrared light source (206) to produce infrared light that exhibits a first polarization and a second infrared light source (206) to produce infrared light that exhibits a second polarization; a camera with a polarizer that passes light having a first polarization or including a detector that is sensitive to a first polarization of capture light; and a computing device configured to: at a first time, operate the first infrared light source to illuminate a portion of a user with infrared light having the first polarization and operate the camera to acquire first raw image data; at a second time, operate the second infrared light source to illuminate the portion of the user with infrared light having the second polarization and operate the camera to acquire second raw image data; and a first infrared light source (206) to produce infrared light that exhibits a first polarization and a second infrared light source (206) to produce infrared light that exhibits a second polarization; a camera with a polarizer that passes light having a first polarization or including a detector that is sensitive to a first polarization of capture light; and a computing device configured to: at a first time, operate the first infrared light source to illuminate a portion of a user with infrared light having the first polarization and operate the camera to acquire first raw image data; at a second time, operate the second infrared light source to illuminate the portion of the user with infrared light having the second polarization and operate the camera to acquire second raw image data; and at a first time, operate the first infrared light source to illuminate a portion of a user with infrared light having the first polarization and operate the camera to acquire first raw image data; at a second time, operate the second infrared light source to illuminate the portion of the user with infrared light having the second polarization and operate the camera to acquire second raw image data; and wherein the system is further configured to: determine a first set of sub-images wherein each sub-image in the first set of sub-images corresponds to a particular area within the first raw image data; determine a first set of feature vectors for one or more of the sub-images in the first set of sub-images; determine a second set of sub-images wherein each sub-image in the second set of sub-images corresponds to a particular area within the second raw image data; determine a second set of feature vectors for one or more of the sub-images in the second set of sub-images; determine, based on the first set of feature vectors and the second set of feature vectors, one or more current signatures; and determine a user identifier based on comparison of the one or more current signatures with one or more previously stored reference signatures. determine a first set of sub-images wherein each sub-image in the first set of sub-images corresponds to a particular area within the first raw image data; determine a first set of feature vectors for one or more of the sub-images in the first set of sub-images; determine a second set of sub-images wherein each sub-image in the second set of sub-images corresponds to a particular area within the second raw image data; determine a second set of feature vectors for one or more of the sub-images in the second set of sub-images; determine, based on the first set of feature vectors and the second set of feature vectors, one or more current signatures; and determine a user identifier based on comparison of the one or more current signatures with one or more previously stored reference signatures.