Abstract: A device for verifying polarization-variant images has first and second illumination arrangements deployed in fixed spatial relation to a camera to illuminate the camera's field of view. A polarizing arrangement is deployed so as to selectively overlie the second illumination source without overlying the first illumination source, thereby allowing switching between differing conditions of polarized illumination without requiring moving optical elements. Also disclosed are various methods employing such a device for authentication and fraud prevention. Alternative implementations employ two cameras with a single illumination arrangement.

Abstract: An authenticatable product comprising a non-opaque latent image layer of anisotropic polymer material having background optical properties with a given preferred direction of anisotropy and a given proportion of crystallinity, the latent image layer being treated so as to include: a first localized modification in the latent image layer being associated with a first latent image; and a second localized modification in the latent image layer being associated with a second latent image such that, when viewed directly, the first latent image and the second latent image are indistinguishable from the remainder of the latent image layer and, under polarized visualization, a maximum contrast between the first latent image and the remainder of the latent image layer is actualized at a different orientation of polarized visualization than a maximum contrast between the second latent image and the remainder of the latent image layer.

Abstract: An authenticatable product comprising a non-opaque latent image layer of anisotropic polymer material having background optical properties with a given preferred direction of anisotropy and a given proportion of crystallinity, the latent image layer being treated so as to include: a first localized modification in the latent image layer being associated with a first latent image; and a second localized modification in the latent image layer being associated with a second latent image such that, when viewed directly, the first latent image and the second latent image are indistinguishable from the remainder of the latent image layer and, under polarized visualization, a maximum contrast between the first latent image and the remainder of the latent image layer is actualized at a different orientation of polarized visualization than a maximum contrast between the second latent image and the remainder of the latent image layer.

Abstract: An authenticatable product includes a non-opaque latent image layer of polymer material treated so as to contain at least one region having anisotropic optical properties such that, when viewed directly, the at least one region is indistinguishable from the remainder of the latent image layer and, under polarized visualization, the at least one region is distinguished readily from the remainder of the latent image layer. The latent image layer may be supplemented with visible information, a reflective layer, a quarterwave plate, a polarizer, or may be part of a more complex multi-layer structure. The product may be used in a wide range of authentification applications. Also described is a method for producing such a latent image including steps of photoactivation, selective exposure and processing/fixing of the image.