Abstract: For canceling acoustic echoing, a processor receives audio signals comprising a speaker output and an ambient input. The processor further calculates separated output signals from mixed signals using a separating transfer function. The processor calculates a criterion function based on the separated output signals. In addition, the processor calculates an acoustic echo transfer function based on maximizing the a criterion function. The processor separates a source signal from the audio signal using the acoustic echo transfer function.

Abstract: For canceling acoustic echoing, a processor receives audio signals comprising a speaker output and an ambient input. The processor further calculates separated output signals from mixed signals using a separating transfer function. The processor calculates a criterion function based on the separated output signals. In addition, the processor calculates an acoustic echo transfer function based on maximizing the a criterion function. The processor separates a source signal from the audio signal using the acoustic echo transfer function.

Abstract: Updating filter coefficients during echo cancellation is disclosed. In some embodiments, a communication device may include a processor configured to operate a background filter configured as an adaptive filter, operate a foreground filter configured as a fixed filter; and update the foreground filter with coefficients from the background filter responsive to monitoring a history of both a near-end signal energy and an estimated far-end signal energy for a pre-determined time window in which conditions of each of the near-end signal energy and the estimated far-end signal energy are satisfied.

Abstract: For synthetic aperture radar (SAR) processing, a SAR receives a plurality of SAR signals. The SAR generates a piecewise approximation of the plurality of SAR signals over a coherent processing interval. The piecewise approximation may mitigate phase reflection components of each SAR signal. The SAR further generates an estimate of the scene from the piecewise approximation.

Abstract: For calculating statistical Markov model-like state transition probabilities, a method represents state transition probabilities between a plurality of statistical Markov model-like states and output probabilities associated with a plurality of previous statistical Markov model-like states. The state transition probabilities between the plurality of previous states depend on a sequence of previous states of the plurality of previous states. The output probabilities associated with each of the plurality of states depend on the sequence of previous states.

Abstract: An acoustic response monitor. The acoustic response monitor includes a speaker, a microphone, and a response analyzer in electrical communication with the speaker and the microphone. The speaker is configured to generate a sound in response to an excitation signal. The microphone is configured to generate a microphone signal in response to a sound. The response analyzer is configured to generate an adaptive filter to minimize a difference between the excitation signal as modified by the adaptive filter and the microphone signal. The response analyzer may be configured to determine a difference between the adaptive filter and a previously generated adaptive filter. The response analyzer may be configured to trigger an alarm if the difference exceeds a predetermined threshold.

Abstract: Updating filter coefficients during echo cancellation is disclosed. In some embodiments, a communication device may include a processor configured to operate a background filter configured as an adaptive filter, operate a foreground filter configured as a fixed filter; and update the foreground filter with coefficients from the background filter responsive to monitoring a history of both a near-end signal energy and an estimated far-end signal energy for a pre-determined time window in which conditions of each of the near-end signal energy and the estimated far-end signal energy are satisfied.

Abstract: Methods and devices for updating filter coefficients during echo cancellation are disclosed. A communication device includes a processor configured to operate a background filter configured as an adaptive filter, operate a foreground filter configured as a fixed filter; and update the foreground filter with coefficients from the background filter responsive to monitoring a history of both a near-end signal energy and an estimated far-end signal energy for a pre-determined time window in which conditions of each of the near-end signal energy and the estimated far-end signal energy are satisfied. A related method includes monitoring a near-end signal energy, monitoring an estimated far-end signal energy, performing an echo cancellation, and transferring coefficients from an adaptive filter to a fixed filter responsive to a history of both the near-end signal energy and the estimated far-end signal energy satisfying conditions for a pre-determined time window.

Abstract: For calculating statistical Markov model-like state transition probabilities, a method represents state transition probabilities between a plurality of statistical Markov model-like states and output probabilities associated with a plurality of previous statistical Markov model-like states. The state transition probabilities between the plurality of previous states depend on a sequence of previous states of the plurality of previous states. The output probabilities associated with each of the plurality of states depend on the sequence of previous states.

Abstract: For synthetic aperture radar (SAR) processing, a SAR receives a plurality of SAR signals. The SAR generates a piecewise approximation of the plurality of SAR signals over a coherent processing interval. The piecewise approximation may mitigate phase reflection components of each SAR signal. The SAR further generates an estimate of the scene from the piecewise approximation.

Abstract: Systems and methods are provided for inserting content into messages being sent between systems or networks. A router according to one embodiment automatically inserts new content within a received data packet. Before insertion, the router may determine that the received data packet corresponds to a certain type of message such as a web page, an e-mail, or a text message. The router may also determine whether the packet includes a predetermined insertion point in the corresponding message. The predetermined insertion point may be, for example, an end of the web page, e-mail, or text message. The type of message and/or the subject matter of the inserted content may be based on user selectable preferences. In one embodiment, a plurality of packets are received before the new content is inserted into the message to improve reliability and/or allow message decoding.

Abstract: Systems and methods are provided for inserting content into messages being sent between systems or networks. A router according to one embodiment automatically inserts new content within a received data packet. Before insertion, the router may determine that the received data packet corresponds to a certain type of message such as a web page, an e-mail, or a text message. The router may also determine whether the packet includes a predetermined insertion point in the corresponding message. The predetermined insertion point may be, for example, an end of the web page, e-mail, or text message. The type of message and/or the subject matter of the inserted content may be based on user selectable preferences. In one embodiment, a plurality of packets are received before the new content is inserted into the message to improve reliability and/or allow message decoding.

Abstract: An echo canceler includes an adaptable filter that is updated during double-talk and far-end talk. The echo canceler receives a microphone signal that includes a near-end signal and echoes resulting from a far-end signal. The echo canceler whitens the far-end signal and decorrelates the microphone signal. The whitening and decorrelating is done as a preprocessing step for the one-unit blind source separation algorithm. A criterion of measure is used to emphasize the statistical independence of the echo canceled signal and the far-end signal. The echo cancellation problem is cast as a one-unit blind source separation problem. A one-unit blind source separation algorithm such as negentropy maximization can be used to extract the echo canceled signal.

Abstract: An echo canceler includes an recursive least squares lattice to whiten a far-end signal s1(t) and provide whitened time delays. The echo canceler further decorrelates a microphone signal based on the whitened time delays to reduce echoes of the far-end signal s1(t) that are contained in the microphone signal x2(t). The echo canceler does not use a double-talk detector and avoids all problems inherent with their use. Thus, speaker phones, and other communication devices, can continuously operate in full-duplex mode of operation thereby providing natural conversational hands-free communication.

Abstract: A highly integrated and flexible system for vending products and services to consumers. The system receives information in advance of the vend by having the consumer insert an identification (ID) card, preferably a driver's license, into a point-of-purchase terminal (referred to as an OSU device). The OSU device preferably contains an Optical Scanning Unit (OSU), capable of scanning the textual information on the ID card. In one embodiment, the scanned information is compared against optical templates present in the system to discern or verify the information on the ID card, and is then used by the system to enable or disable the vending transaction, and/or to allow access to several preregistered system accounts.

Abstract: Disclosed is a highly integrated and flexible system for vending products and services to consumers. The system receives information in advance of the vend by having the consumer insert an identification (ID) card, preferably a driver's license, into a point-of-purchase terminal (referred to as an OSU device). The OSU device preferably contains an Optical Scanning Unit (OSU), capable of scanning the textual information on the ID card. In one embodiment, the scanned information is compared against optical templates present in the system to discern or verify the information on the ID card, and is then used by the system to enable or disable the vending transaction, and/or to allow access to several preregistered system accounts.