1. A device, comprising: a biometric sensor; and a processing system configured to: receive, from the biometric sensor, an input image of a biometric; obtain keypoint locations of keypoints in the input image, wherein keypoints in the input image comprise local regions of interest in the input image; generate a scaled image by scaling the input image to a smaller size; determine that two or more keypoints in the input image comprise a cluster of keypoints in response to determining that keypoint locations of the two or more keypoints in the input image correspond to a same pixel in the scaled image; compute one or more anti-spoof metrics of the input image based on the keypoint locations, wherein the one or more anti-spoof metrics comprise a metric corresponding to a number of clusters of keypoints in the input image; and determine whether the input image is a replica of the biometric based on the one or more anti-spoof metrics.