A method includes obtaining, by a processing device from an optical sensor of a mobile device, an image of an object; processing, by the processing device, the image using a neural network, wherein processing the image includes distinguishing, using the neural network, a first portion of the image including a region of interest, ROI, from a second portion of the image; after processing the image, extracting, by the processing device, a biometric characteristic of the object from the ROI; and processing, by the processing device, the biometric characteristic of the object to determine whether the biometric characteristic of the object identifies a user.