Abstract: The present disclosure may be embodied as systems and methods for action recognition developed using a multimodal dataset that incorporates both visual data, which facilitates the accurate tracking of movement, and active acoustic data, which captures the micro-Doppler modulations induced by the motion. The dataset includes twenty-one actions and focuses on examples of orientational symmetry that a single active ultrasound sensor should have the most difficulty discriminating. The combined results from three independent ultrasound sensors are encouraging, and provide a foundation to explore the use of data from multiple viewpoints to resolve the orientational ambiguity in action recognition. In various embodiments, recurrent neural networks using long short-term memory (LSTM) or hidden Markov models (HMMs) are disclosed for use in action recognition, for example, human action recognition, from micro-Doppler signatures.

Abstract: The present disclosure may be embodied as systems and methods for action recognition developed using a multimodal dataset that incorporates both visual data, which facilitates the accurate tracking of movement, and active acoustic data, which captures the micro-Doppler modulations induced by the motion. The dataset includes twenty-one actions and focuses on examples of orientational symmetry that a single active ultrasound sensor should have the most difficulty discriminating. The combined results from three independent ultrasound sensors are encouraging, and provide a foundation to explore the use of data from multiple viewpoints to resolve the orientational ambiguity in action recognition. In various embodiments, recurrent neural networks using long short-term memory (LSTM) or hidden Markov models (HMMs) are disclosed for use in action recognition, for example, human action recognition, from micro-Doppler signatures.

Abstract: A computational sensing array includes an array of sensing elements. In each sensing element, a first signal is generated from a transducer. A second signal is produced by a collection unit in response to receiving the first signal. The second signal may be modified, in a conditioning unit. A sensing element preprocessing unit generates a word representing the value of the modified second signal, and may produce an indication of change of the first signal. A current value of the word may be stored in a state holding element local to the sensing element, and a previous value of the word may be retained in a further state holding element local to the sensing element.

Abstract: A photodetection circuit includes an avalanche photodiode and a mode switching circuit that may be configured to selectively switch an operating mode of the photodetection circuit between linear mode and Geiger mode. The photodetection circuit may further include a quenching circuit configured to quench and reset the avalanche photodiode in response to an avalanche event when the photodetection circuit is operated in Geiger mode. The photodetection circuit may additionally include an integration circuit configured to integrate photocurrent output by the photodiode and generate integrated charge units when the photodetection circuit is operated in linear mode. The photodetection circuit may also include a counter configured to count pulses output by the avalanche photodiode when the photodetection circuit is operated in Geiger mode and to count integrated charge units generated by the integration circuit when the photodetection circuit is operated in linear mode.

Abstract: A computational sensing array includes an array of sensing elements. In each sensing element, a first signal is generated from a transducer. A second signal is produced by a collection unit in response to receiving the first signal. The second signal may be modified, in a conditioning unit. A sensing element preprocessing unit generates a word representing the value of the modified second signal, and may produce an indication of change of the first signal. A current value of the word may be stored in a state holding element local to the sensing element, and a previous value of the word may be retained in a further state holding element local to the sensing element.

Abstract: A computational sensing array includes an array of sensing elements. In each sensing element, a first signal is generated from a transducer. A second signal is produced by a collection unit in response to receiving the first signal. The second signal may be modified, in a conditioning unit. A sensing element preprocessing unit generates a word representing the value of the modified second signal, and may produce an indication of change of the first signal. A current value of the word may be stored in a state holding element local to the sensing element, and a previous value of the word may be retained in a further state holding element local to the sensing element.

Abstract: A photodetection circuit includes an avalanche photodiode and a mode switching circuit that may be configured to selectively switch an operating mode of the photodetection circuit between linear mode and Geiger mode. The photodetection circuit may further include a quenching circuit configured to quench and reset the avalanche photodiode in response to an avalanche event when the photodetection circuit is operated in Geiger mode. The photodetection circuit may additionally include an integration circuit configured to integrate photocurrent output by the photodiode and generate integrated charge units when the photodetection circuit is operated in linear mode. The photodetection circuit may also include a counter configured to count pulses output by the avalanche photodiode when the photodetection circuit is operated in Geiger mode and to count integrated charge units generated by the integration circuit when the photodetection circuit is operated in linear mode.

Abstract: A computational sensing array includes an array of sensing elements. In each sensing element, a first signal is generated from a transducer. A second signal is produced by a collection unit in response to receiving the first signal. The second signal may be modified, in a conditioning unit. A sensing element preprocessing unit generates a word representing the value of the modified second signal, and may produce an indication of change of the first signal. A current value of the word may be stored in a state holding element local to the sensing element, and a previous value of the word may be retained in a further state holding element local to the sensing element.

Abstract: A computational sensing array includes an array of sensing elements. In each sensing element, a first signal is generated from a transducer. A second signal is produced by a collection unit in response to receiving the first signal. The second signal may be modified, in a conditioning unit. A sensing element preprocessing unit generates a word representing the value of the modified second signal, and may produce an indication of change of the first signal. A current value of the word may be stored in a state holding element local to the sensing element, and a previous value of the word may be retained in a further state holding element local to the sensing element.

Abstract: An avalanche photodiode is disclosed. The avalanche photodiode includes a substrate of a first conductivity type. A first well of a second conductivity type is formed within the substrate. A second well of the second conductivity type is formed substantially overlying and extending into the first well. A heavily doped region of the first conductivity type is formed substantially overlying and extending into the first well, the junction between the heavily doped region and the second well forming an avalanche multiplication region. A guard ring is formed from a first conductivity material positioned substantially about the periphery of the multiplication region at least partially underlying the heavily doped region. An outer well ring of the second conductivity type is formed about the perimeter of the deep well and the guard ring.

Abstract: An avalanche photodiode and a sensor array comprising an array of said avalanche photodiodes is disclosed. Then avalanche photodiode comprises a substrate of a first conductivity type; a first well of a second conductivity type formed within the substrate; a second well of the second conductivity type formed substantially overlying and extending into the first well; a heavily doped region of the first conductivity type formed substantially overlying and extending into the first well, the junction between the heavily doped region and the second well forming an avalanche multiplication region; a guard ring formed from a first conductivity material positioned substantially about the periphery of the multiplication region at least partially underlying the heavily doped region; and an outer well ring of the second conductivity type formed about the perimeter of the deep well and the guard ring.

Abstract: An integrated electronic-optoelectronic module comprising: an ultrathin silicon-on-sapphire composite substrate; at least one electronic device fabricated in the ultrathin silicon; and at least one optoelectronic device bonded to the ultrathin silicon-on-sapphire composite substrate and in electrical communication with the at least one electronic device fabricated in the ultrathin silicon layer. For example, VCSELs and photodetectors are integrated with CMOS electronic circuitry to provide useful modules for electro-optical interconnects for computing and switching systems.

Abstract: A two transistor current-controlled current conveyor (C4) circuit is provided which exploits the translinear properties of the MOS transistor in subthreshold and uses unidirectional current signals. As a result, the circuits of the invention achieve high functionality and integration density with very low power dissipation. Two C4 circuits connected to and communicating through a bidirectional junction circuit of the invention permit the transmission of independent, bidirectional signals. These circuits are useful for implementing synthetic neural systems such as associative memories and silicon retinas, such as winner-takes-all and pyramidal neuron circuits and the outer-plexiform layer of a retina.