Abstract: The described techniques support a sensing scheme for electromagnetic excitation in ultrasonic imaging sensors. A biological tissue may be sensed and imaged using an electromagnetic excitation process to generate ultrasonic waves, such as, within the tissue. A component of a device may generate one or more pulses of electromagnetic waves, which may encounter and enter the biological tissue. The electromagnetic waves may excite the biological tissue and generate ultrasonic waves via expansion and contraction of the tissue upon heating. The ultrasonic waves may propagate within the biological tissue and may be sensed by an ultrasonic receiver array. The ultrasonic waves may be converted to pixel image data of a biometric image and may be used for biometric authentication. This process may be repeated to reconstruct an image of the finger at multiple plane slices of the finger.

Abstract: Some disclosed methods involve controlling, via a control system, a light source system to emit a plurality of light pulses into biological tissue at a pulse repetition frequency, the biological tissue including blood and blood vessels at depths within the biological tissue. Such methods may involve receiving, by the control system, signals from the piezoelectric receiver corresponding to acoustic waves emitted from portions of the biological tissue, the acoustic waves corresponding to photoacoustic emissions from the blood and the blood vessels caused by the plurality of light pulses. Such methods may involve detecting, by the control system, heart rate waveforms in the signals, determining, by the control system, a first subset of detected heart rate waveforms corresponding to vein heart rate waveforms and determining, by the control system, a second subset of detected heart rate waveforms corresponding to artery heart rate waveforms.

Abstract: An object having an outer surface (e.g. a friction-ridge surface of a finger) and internal parts (e.g. tissue layer, papillae, blood vessels, fat, muscle, nail and bone) is scanned by a system having a transmitter, receiver and computer. One such system has a substantially planar piezoelectric transmit-layer, an ultrasonic receiver array having a plurality of receivers, and a platen. The transmit layer is caused to produce an ultrasound plane-wave traveling toward the object residing on the platen. Using the ultrasonic receiver, ultrasonic energy that has been reflected from the object is detected. The detected ultrasonic energy is analyzed to provide an analysis result, and the analysis result is compared to a template. A determination is made as to whether the analysis result and the template are similar, and the object is declared to be alive if the analysis result is determined to be similar to the template.

Abstract: An apparatus includes an ultrasonic transmitter, an ultrasonic receiver, and an acoustic delay gradient layer disposed in an acoustic path between the ultrasonic transmitter and the ultrasonic receiver. The acoustic delay gradient layer is configured to cause a reflection from a platen interface of the transmitted ultrasonic signal to reach the first receiver region at a first time and the reflection from the platen interface of the transmitted ultrasonic signal to reach the second receiver region at a second time that is different from the first time. The apparatus can further include a controller configured to set for a first region or portion of the receiver, a first range gate window (RGW). The controller is also configured to set, for a second region or portion of the receiver, a second RGW, and to establish a first temporal delay between the first RGW and the second RGW.

Abstract: An apparatus may include a cover layer, a layer of first metamaterial proximate (or in) the cover layer, a light source system configured for providing light to the layer of first metamaterial and a receiver system. The first metamaterial may include nanoparticles configured to create ultrasonic waves when illuminated by light. The receiver system may include an ultrasonic receiver system configured to receive ultrasonic waves reflected from a target object in contact with, or proximate, a surface of the cover layer. The control system may be configured to receive ultrasonic receiver signals from the ultrasonic receiver system corresponding to the ultrasonic waves reflected from the target object and to perform an authentication process and/or an imaging process that is based, at least in part, on the ultrasonic receiver signals.

Abstract: Disclosed are methods, devices, apparatuses, and systems for poling a piezoelectric film. A poling system can be a corona poling system including a corona source with one or more corona wires configured to transfer a corona discharge onto a major surface of the piezoelectric film. The poling system can further include a grid electrode interposed between the corona source and the piezoelectric film. A substrate including the piezoelectric film may be supported on a substrate support, where the substrate and the corona source are configured to move relative to each other during poling.

Abstract: An apparatus may include a cover layer, a layer of first metamaterial proximate (or in) the cover layer, a light source system configured for providing light to the layer of first metamaterial and a receiver system. The first metamaterial may include nanoparticles configured to create ultrasonic waves when illuminated by light. The receiver system may include an ultrasonic receiver system configured to receive ultrasonic waves reflected from a target object in contact with, or proximate, a surface of the cover layer. The control system may be configured to receive ultrasonic receiver signals from the ultrasonic receiver system corresponding to the ultrasonic waves reflected from the target object and to perform an authentication process and/or an imaging process that is based, at least in part, on the ultrasonic receiver signals.

Abstract: The described techniques support a sensing scheme for electromagnetic excitation in ultrasonic imaging sensors. A biological tissue may be sensed and imaged using an electromagnetic excitation process to generate ultrasonic waves, such as, within the tissue. A component of a device may generate one or more pulses of electromagnetic waves, which may encounter and enter the biological tissue. In some examples, the component may be a display interface or may be different from a display interface of the device. The electromagnetic waves may excite the biological tissue and generate ultrasonic waves via expansion and contraction of the tissue upon heating. The ultrasonic waves may propagate within the biological tissue and may be sensed by an ultrasonic receiver array. The sensed ultrasonic waves may be converted to pixel image data of a biometric image and may be used for biometric authentication.

Abstract: An apparatus may include an ultrasonic sensor array and a control system. The control system may be configured to acquire first image data generated by the ultrasonic sensor array corresponding to at least one first reflected ultrasonic wave received by at least a portion of the ultrasonic sensor array from a target object during a first acquisition time window. The control system may be configured to acquire second image data generated by the ultrasonic sensor array corresponding to at least one second reflected ultrasonic wave received by at least a portion of the ultrasonic sensor array from the target object during a second acquisition time window that is longer than the first acquisition time window. The control system may further be configured to initiate an authentication process based on the first image data and the second image data.

Abstract: A subdermal imaging system which may determine whether a person's body is in contact with a display, and perform a subdermal imaging process to determine subdermal characteristics by a photoacoustic imaging process. Ultrasonic emissions emitted from the photoacoustic process may be received with an ultrasonic receiver array. The subdermal imaging system may adjust the wavelength and/or intensity of the photoacoustic process in order to image desired subdermal features.

Abstract: The described techniques support a sensing scheme for electromagnetic excitation in ultrasonic imaging sensors. A biological tissue may be sensed and imaged using an electromagnetic excitation process to generate ultrasonic waves, such as, within the tissue. A component of a device may generate one or more pulses of electromagnetic waves, which may encounter and enter the biological tissue. In some examples, the component may be a display interface or may be different from a display interface of the device. The electromagnetic waves may excite the biological tissue and generate ultrasonic waves via expansion and contraction of the tissue upon heating. The ultrasonic waves may propagate within the biological tissue and may be sensed by an ultrasonic receiver array. The sensed ultrasonic waves may be converted to pixel image data of a biometric image and may be used for biometric authentication.

Abstract: The described techniques support a sensing scheme for electromagnetic excitation in ultrasonic imaging sensors. A biological tissue may be sensed and imaged using an electromagnetic excitation process to generate ultrasonic waves, such as, within the tissue. A component of a device may generate one or more pulses of electromagnetic waves, which may encounter and enter the biological tissue. The electromagnetic waves may excite the biological tissue and generate ultrasonic waves via expansion and contraction of the tissue upon heating. The ultrasonic waves may propagate within the biological tissue and may be sensed by an ultrasonic receiver array. The ultrasonic waves may be converted to pixel image data of a biometric image and may be used for biometric authentication. This process may be repeated to reconstruct an image of the finger at multiple plane slices of the finger.

Abstract: An apparatus includes an ultrasonic sensor array and a sensor controller. The sensor array includes a plurality of ultrasonic sensor pixels, each sensor pixel including an ultrasonic receiver and a receiver bias electrode and being operable in one or both of a transmit mode of operation or a read mode of operation. The sensor controller is electrically coupled with the receiver bias electrodes. The sensor controller is configured to set, at each sensor pixel, a range gate window (RGW) by modulating a bias voltage applied to the receiver bias electrode and to set, for a first portion of the ultrasonic sensor pixels, a first RGW. The sensor controller is configured to set, for a second portion of the ultrasonic sensor pixels, a second RGW, and establish a first temporal delay between the first RGW and the second RGW.

Abstract: An apparatus may include an ultrasonic sensor system and a control system. The control system may be configured to distinguish, according to image data acquired via an ultrasonic sensor system, the pyroelectric effect caused by an actual human finger from the pyroelectric effect caused by a sleeve-type spoof or a “fake finger” spoof. Some such examples involve obtaining multiple frames of ultrasonic image data of a target object on or near a platen of an ultrasonic sensor system via the ultrasonic sensor system and determining at least one target object pyroelectric indication based, at least in part, on the multiple frames of ultrasonic image data.

Abstract: A system and method for ultrasonic sensing, wherein an ultrasonic receiver array includes multiple ultrasonic sensor pixels, and each sensor pixel includes an ultrasonic receiver configured to read an ultrasonic signal. An ultrasonic transmitter array, composed of multiple elements, transmits ultrasonic signals which may be reflected from an object and received at the ultrasonic receivers, wherein a sensor controller applies excitation signals to the transmitter array with a temporal delay between excitation signals.

Abstract: An apparatus may include an ultrasonic sensor system and a control system. The control system may be configured to distinguish, according to image data acquired via an ultrasonic sensor system, the pyroelectric effect caused by an actual human finger from the pyroelectric effect caused by a sleeve-type spoof or a “fake finger” spoof. Some such examples involve obtaining multiple frames of ultrasonic image data of a target object on or near a platen of an ultrasonic sensor system via the ultrasonic sensor system and determining at least one target object pyroelectric indication based, at least in part, on the multiple frames of ultrasonic image data.

Abstract: An ultrasonic reflex imaging device and a method are described. A device according to the invention may include a platen, a generator, and a receiver positioned between the platen and the generator. A backer may be positioned so that the insonification device is between the receiver array and the backer. The backer may be configured to absorb or delay energy that originated from the generator. The generator produces an energy pulse, which travels through the receiver and the platen to reach a biological object. Part of the energy pulse is reflected from the biological object. The reflected energy pulse travels through the platen to the detector. The detector converts the reflect energy pulse to electric signals, which are then interpreted to create an image of the biological object.

Abstract: A subdermal imaging system which may determine whether a person's body is in contact with a display, and perform a subdermal imaging process to determine subdermal characteristics by a photoacoustic imaging process. Ultrasonic emissions emitted from the photoacoustic process may be received with an ultrasonic receiver array. The subdermal imaging system may adjust the wavelength and/or intensity of the photoacoustic process in order to image desired subdermal features.

Abstract: Systems and methods for multi-spectral ultrasonic imaging are disclosed. In one embodiment, a finger is scanned at a plurality of ultrasonic scan frequencies. Each scan frequency provides an image information set describing a plurality of pixels of the finger including a signal-strength indicating an amount of energy reflected from a surface of a platen on which a finger is provided. For each of the pixels, the pixel output value corresponding to each of the scan frequencies is combined to produce a combined pixel out put value for each pixel. Systems and methods for improving the data capture of multi-spectral ultrasonic imaging are also disclosed.

Abstract: Methods and systems of determining whether an object is alive, and therefore part of a live individual, are described. An object having an outer surface (e.g. a friction-ridge surface of a finger) and internal parts (e.g. tissue layer, papillae, blood vessels, fat, muscle, nail and bone) is scanned by a system having a transmitter, receiver and computer. One such system has a substantially planar piezoelectric transmit-layer, an ultrasonic receiver array having a plurality of receivers, and a platen. The transmit layer is caused to produce an ultrasound plane-wave traveling toward the object residing on the platen. Using the ultrasonic receiver, ultrasonic energy that has been reflected from the object is detected. The detected ultrasonic energy is analyzed to provide an analysis result, and the analysis result is compared to a template.