1. A method of evaluating genuineness of a sample presented for biometric evaluation, the method comprising: illuminating the sample under a plurality of distinct optical conditions; receiving light scattered from the sample for each of the plurality of distinct optical conditions; forming a plurality of images, each such image being formed from the received light for a respective one of the plurality of distinct optical conditions; generating a plurality of texture measures, each such texture measure being generated from a respective one of the plurality of images; and determining whether the generated plurality of texture measures is consistent with the sample being authentic unconcealed biological tissue.