Last month Patently Apple posted a report titled "Apple's Next-Gen Touch ID uses Optical Imaging Sensors under a Display for a Variety of Devices like Apple Watch." Today the U.S. Patent and Trademark Office published another granted patent relating to a possible Touch ID alternative methodology that will allow users to simply touch the display of an iDevice for biometric authentication.

Apple's newly granted patent 10,275,638 titled "Methods of biometric imaging of input surfaces" covers their invention relating to an acoustic imaging system. More specifically, the acoustic imaging system may be configured to resolve an image of a fingerprint of a user contacting an input surface of an electronic device by mapping the ridges of the user's fingerprint to the input surface.

The acoustic imaging system includes a number of acoustic transducers that are configured to generate acoustic outputs (e.g., mechanical waves, acoustic waves, or pulses) into the user input surface in response to a signal from a controller. The controller is configured to provide coded signals such that the acoustic outputs are also coded.

In some embodiments, the acoustic imaging system can employ one or more tomographic reconstruction techniques (e.g., reflection, diffraction, transmission, and so on) to obtain the image of the fingerprint. A tomographic acoustic imaging system includes a controller configured to induce an acoustic pulse or wave within the user input surface. The controller generates the acoustic pulse by applying a drive signal to one or more acoustic transducers then operating in a drive mode. When in the drive mode, an acoustic transducer deforms in response to the drive signal. The drive signal is configured to induce an acoustic pulse (such as a surface wave, shear wave, plane wave, or other acoustic pulse type) that propagates through the thickness of, or across a surface of, the user input surface. In some examples, the acoustic pulse can be a Gaussian pulse, a chirp signal (e.g., multiple periods of varying frequency), a sinusoidal burst (e.g., multiple periods of a single frequency), or any other suitable pulse type or shape.

In many embodiments, the tomographic acoustic imaging system also includes an image resolver configured to construct an image of the object at the contact area. The image resolver receives multiple planar projections (filtered or otherwise) from the controller and assembles an image of the object at the contact area using, in one example, a filtered back projection technique.

Apple's patent FIG. 1 depicts an example electronic device that can incorporate an acoustic imaging system; FIG. 3A depicts a distribution of acoustic transducers associated with an acoustic imaging system; FIG. 6 depicts an acoustic imaging system, particularly showing one example distribution of acoustic transducers positioned relative to a top and bottom edge of a rectangular subarea of the imaging surface.

Apple's patent FIG. 13 above is a flow chart that corresponds to a method of operating an acoustic imaging system.

Apple further notes that an acoustic imaging system can be configured to map the biometrically-unique features of a user finger for size, shape, skin patterns, and scar patterns and so on.

Apple also oddly notes, that as far as the iPhone goes, the system could also be used to capture the characteristics of user's ears, map it, and use it as another biometric authentication technique.

Apple later notes that although many embodiments are described in terms of a system and method for generating an image of a user's fingerprint, these systems and methods can alternatively or additionally be used to perform other operations, or to obtain non-fingerprint information, such as, but not limited to: generating an image of a palm; generating an image of an ear, face, or cheek; determining the location of a stylus on an input surface of an electronic device; determining a physiological characteristic of a user such as heart rate, respiration rate, blood oxygenation, and so on; determining characteristics of a non-input surface; determining the force with which a user touches an input surface; determining the location at which a user touches an input surface; and so on. Accordingly, it may be appreciated that the various systems and methods presented below are merely examples and that other embodiments, systems, methods, techniques, apparatuses, and combinations thereof.

Apple's granted patent was originally filed in Q3 2016 and published today by the US Patent and Trademark Office.