The United States of America as Represented by the National Security Agency

Other

The United States of America, as Represented by the Director, National Security Agency

The United States of America as Represented by the Director of the National Security Agency

David C Smith

Douglas J Nelson

Rajiv Jain

Michael Shawn Lawler

Daniel J Richman

Jeffrey L Townsend

Single-image super-resolution (SISR) is the problem of generating a high resolution image from a single low resolution image. The SISR technique known as neighbor embedding utilizes a training ensemble of pairs of low and high resolution image patches, where the patches in a given pair represent the same image region. The present invention improves upon prior neighbor embedding algorithms by offering a practical, computationally efficient method of neighbor embedding for generating a high resolution version of a low resolution image. The technique may also be applied to generate high resolution versions of low resolution text images for subsequent input into OCR engines. OCR character error rates found on the high resolution images are drastically lower than those found when OCR is applied to the original low resolution text images.

Method of neighbor embedding for OCR enhancement

A camera rig system is configured to film in several overlapping directions at once. The camera rig system has a front rig having a first plurality of cameras arranged to film in a first set of overlapping directions. A trigger box is electrically coupled to the front rig and configured to receive data from the first plurality of cameras. A rear rig having a second plurality of cameras is electrically coupled to the trigger box and arranged to film in a second set of overlapping directions. The first set of overlapping directions and the second set of overlapping directions are configured such that images taken from the first plurality of cameras and the second plurality of cameras can reflect background images around the camera rig system.

Camera rig

A method of demodulating an AIS signal by receiving the signal, sampling the signal, estimating the carrier frequency, estimating the complex conjugate of the carrier frequency contribution to each sample, multiplying each sample by the complex conjugate and calling the results a base-banded sampled signal (BBSS), correlating the BBSS with known preambles, identifying a maximum magnitude of the BBSS/preamble correlation and its location and the associated preamble, computing a complex inner product of the preamble with a segment of the BBSS, estimating the carrier phase as an argument function of the eighth step result, estimating a complex conjugate of the carrier phase contribution to the BBSS, multiplying each fifth step result starting at the location of the maximum magnitude of the BBSS/preamble correlation by the tenth step result, and demodulating the results starting at that location.

AIS demodulator for unknown carrier phase and baud alignment

A device and method of geolocating a transmitter. First and second receivers, in motion, receive a signal from the transmitter. Digitizers in the receivers digitize the signal. Converters in the receivers for converting the digitized signals to complex-valued signals. Transmitters on the receivers transmit their digitized signals, locations, and velocities at the time the signal was received to a processor. A central processing unit on the processor determines a difference in radial velocities of the receivers relative to the transmitter. The difference in radial velocities and delay time between the signals received at the receivers are used to geolocate the transmitter.

Device for and method of geolocation

The present invention is a method of finding range and velocity of a target in a radar system using a time scale factor. Specifically, sending at least one signal from at least one transmitter to a target. A return signal is then received from the target at each transmitter and the elapsed time is recorded. The range to the target and velocity of the target are calculated based on a time scale factor of the recorded elapsed times. These values are appropriately output to the user.

Method of signal processing for determining range and velocity of an object

A method of removing noise and interference from a signal by receiving the signal, calculating a joint time-frequency domain of the signal, estimating instantaneous frequencies of the joint time-frequency domain, modifying each estimated instantaneous frequency, if necessary, to correspond to a frequency of the joint time-frequency domain to which it most closely compares, redistributing the elements within the joint time-frequency domain according to the estimated instantaneous frequencies as modified, computing a magnitude for each element in the joint time-frequency domain as redistributed, plotting the results as the time-frequency representation of the signal, identifying in the plot any noise and interference components in the received signal, eliminating from the redistributed joint time-frequency domain elements that correspond to noise and interference, and recovering a signal devoid of noise and interference from the modified redistributed joint time-frequency domain.

Method of removing noise and interference from signal

The present invention is a method of finding propagation time and velocity of a transmitter. Specifically, receiving a signal at two or more receivers and using the scalar time relationship to determine propagation time and velocity of the transmitter for the purpose of location of the transmitter. This method is useful for both narrowband and broadband applications with increased accuracy over previous methods.

Method of signal processing

A method of generating a time-frequency representation of a signal that preserves phase information by receiving the signal, calculating a joint time-frequency domain of the signal, estimating instantaneous frequencies of the joint time-frequency domain, modifying each estimated instantaneous frequency, if necessary, to correspond to a frequency of the joint time-frequency domain to which it most closely compares, redistributing the elements within the joint time-frequency domain according to the estimated instantaneous frequencies as modified, computing a magnitude for each element in the joint time-frequency domain as redistributed, and plotting the results as the time-frequency representation of the signal.

Method of generating time-frequency signal representation preserving phase information

The present invention is a method of modeling a single class of data from data containing multiple classes of data of the same type of data by first receiving a collection of data that includes data from multiple classes of data of the same type where the amount of data of the single class of data exceeds that of any other class of data. A first statistical model of the received collection of data is generated. The collection of data is divided into subsets. Each subset of the speech collection of data is scored using the first statistical model. A set of scores is selected. The subsets corresponding to the selected scores are identified. The identified subsets are combined. A second statistical model of the type of the first statistical model is generated for the combined subsets and used as the model of the single class of data.

Method of modeling single data class from multi-class data

The present invention is a device for and method of detecting voice activity. First, the AM envelope of a segment of a signal of interest is determined. Next, the number of times the AM envelope crosses a user-definable threshold is determined. If there are no crossings, the segment is identified as non-speech. next, the number of points on the AM envelope within a user-definable range is determined. If there are less than a user-definable number of points within the range, the segment is identified as non-speech. Next, the mean, variance, and power ratio of the normalized spectral content of the AM envelope is found and compared to the same for known speech and non-speech. The segment is identified as being of the same type as the known speech or non-speech to which it most closely compares. These steps are repreated for each signal segment of interest.

Device for and method of detecting voice activity

The present invention is a device for and method of detecting voice activity by receiving a signal; computing the absolute value of the signal; squaring the absolute value; low pass filtering the squared result; computing the mean of the filtered signal; subtracting the mean from the filtered result; padding the mean subtracted result with zeros to form a value that is a power of two if the result is not already a power of two; computing a DFFT of the power of two result; normalizing the DFFT result of the last step; computing a mean of the normalization; computing a variance of the normalization; computing a power ratio of the normalization; classifying the mean, variance and power ratio as speech or non-speech based on how this feature vector compares to similarly constructed feature vectors of known speech and non-speech. The voice activity detector includes an absolute value squarer; a low pass filter; a mean subtractor; a zero padder; a DFFT; a normalizer; and a classifier.

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Columbia, MD, United States of America

David C Smith