A fingerprint acquisition device comprising, a space for receiving a finger of a user, a light source configured to emit a illumination light illuminating the space, a camera configured to acquire an image of a fingerprint of the finger, when the finger is received in the space, and, a polarization system configured to polarize the illumination light before the illumination light reaches the space and after the illumination light has passed through the space, and to polarize an ambient light emanating from outside the device and propagating towards the camera, before the ambient light reaches the space, and to polarize the ambient light after the ambient light has passed through the space.

An optical fingerprint sensor with spoof detection using polarization includes a plurality of lenses; an image sensor including a pixel array that includes a plurality of first photodiodes; a line between a center of a light-sensitive surface of each first photodiode and an optical center of each lens forms an optical axis of a plurality of optical axes; at least one apertured baffle-layer positioned between the image sensor and the plurality of lenses and each having a respective plurality of aperture stops, each aperture stop being center-aligned with the optical axis; a plurality of second photodiodes intercalated with the plurality of first photodiodes, wherein each second photodiode is configured to detect light having passed through lens and at least one aperture stop not aligned along optical axis; and at least one polarizing element positioned to polarize electromagnetic energy impinging the plurality of second photodiodes.

A method may involve obtaining a latent fingerprint on a surface, storing the latent fingerprint, obtaining a live fingerprint on the surface, and authenticating the live fingerprint based in part on the stored latent fingerprint and in part on previously-authenticated fingerprint data. The method may involve rejecting authentication of the live fingerprint as a potential spoof, if the live fingerprint matches the latent fingerprint under a relatively strict correlation test. The method may also involve, when the live fingerprint doesn’t closely match the latent fingerprint, granting authentication of the live fingerprint if the live fingerprint matches the previously-authenticated fingerprint data under a relatively loose correlation test.

A method for detecting spoof fingerprints detected using an optical fingerprint sensor and polarization includes controlling a display of an electronic device to output a pattern of light to illuminate a fingerprint sample touching the display; blocking smaller-angle light from impinging a plurality of anti-spoof photodiodes of the pixel array; filtering larger-angle light incident on the plurality of anti-spoof photodiodes to at least one polarization direction; detecting the larger-angle light using the plurality of anti-spoof photodiodes; correlating the larger-angle light with the pattern of light; determining the fingerprint spoofing based at least in part on the correlation of the larger-angle light and the pattern of light; and wherein the plurality of anti-spoof photodiodes is interleaved with a plurality of imaging photodiodes such that each anti-spoof photodiode of the plurality of anti-spoof photodiodes is between adjacent imaging photodiodes of the plurality of imaging photodiodes.

An optical fingerprint sensor with spoof detection includes a plurality of lenses; a pixel array including a plurality of first photodiodes, a line between a center of each first photodiode and an optical center of each lens forms an optical axis; at least one apertured baffle-layer positioned between the image sensor and the plurality of lenses, each having a respective plurality of aperture stops, each aperture stop being center-aligned with the optical axis; and a plurality of second photodiodes intercalated with the plurality of first photodiodes; and a color filter layer between the pixel array and the plurality of lenses, said color filter layer includes a plurality of color filters positioned such that each second photodiode is configured to detect electromagnetic energy having passed through lens, a color filter, and at least one aperture stop not aligned along the optical axis.

An optical fingerprint sensor with spoof detection includes a plurality of lenses, an image sensor including a pixel array that includes a plurality of first photodiodes and a plurality of second photodiodes, and at least one apertured baffle-layer having a plurality of aperture stops, wherein each second photodiode is configured to detect light having passed through a lens and at least one aperture stop not aligned with the lens along an optical axis. A method for detecting spoof fingerprints detected using an optical fingerprint sensor includes detecting large-angle light incident on a plurality of anti-spoof photodiodes, wherein the plurality of anti-spoof photodiodes is interleaved with a plurality of imaging photodiodes, determining an angular distribution of light based at least in part one the large-angle light, and detecting spoof fingerprints based at least in part on the angular distribution of light.

A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.

The present invention relates to a method for biometric authentication of a user of an electronic device comprising an optical fingerprint sensor arranged under an at least partially transparent display panel and configured to capture an image of an object located on an opposite side of the transparent display panel, the method comprises the steps of: illuminating the object with light of at least one distinguishable color; capturing at least two images of the object with an image sensor comprising a photodetector pixel array while illuminating the object with the light of at least one distinguishable color, wherein the images are captured for different applied forces by the object on the transparent display panel; and performing biometric authentication at least partly based on at least one relationship between the at least two images, the at least one relationship being related to a difference in pixel intensity from pixels in the photodetector pixel array arranged to detect light of the distinguishable color.

A computer-implemented method for identifying a user, the method using a computing device comprising an illumination source that, when activated, emits visible light, the method comprising taking two images of a scene potentially comprising a living body part carrying a biometric characteristic, wherein a first image is taken without the illumination source being activated and the second image is taken with the illumination source being activated, transferring the first image and the second image to a neural network and processing, by the neural network the first image and the second image, wherein the processing comprises comparing the first image and the second image, thereby determining whether the first image and the second image are images of a living body part, the method further comprising, if it is determined that the first image and the second image are images of a living body part, performing an identification algorithm to find a biometric characteristic for identifying the user and, if it is determined that the first image and the second image are not images of a living body part, not performing the identification algorithm.

A sensing device includes a substrate, a first circuit, a second circuit, a first photodetector, and a second photodetector. The substrate has a sensing region. The first circuit is disposed on the substrate and in the sensing region, and configured to sense a fingerprint. The second circuit is disposed on the substrate and in the sensing region, and configured to sense a living body. The first photodetector is electrically connected to the first circuit. The second photodetector is electrically connected to the second circuit. The area of the second photodetector is larger than the area of the first photodetector.