System and method of noise reduction
A system for signal detection including a receiver, a transforming block, a noise reduction block, and an object detection block. The receiver is adapted to provide an initial dataset sampled in a time domain over a frequency range. The transforming block is adapted to receive the initial dataset and convert the initial dataset from the time domain to a multi-channel time-frequency domain array. The noise reduction block is adapted to receive the multi-channel time-frequency domain array and provide a clean data set, wherein the clean data set is defined as a noise signal subtracted from the multi-channel time-frequency domain array. The object detection block is adapted to receive the clean dataset and to provide a bounded data set, wherein the bounded data set is defined by a bounding box associated with a portion of the multi-channel time-frequency domain array containing a signal with energy above a threshold level.
1. A system for signal detection comprising:
a receiver adapted to provide an initial dataset sampled in a time domain over a frequency range;
a transforming block adapted to receive the initial dataset and convert the initial dataset from the time domain to a multi-channel time-frequency domain array;
a noise reduction block adapted to receive the multi-channel time-frequency domain array and provide a clean data set, wherein the clean data set is defined as a noise signal subtracted from the multi-channel time-frequency domain array; and
an object detection block adapted to receive the clean dataset and to provide a bounded data set, wherein the bounded data set is defined by a bounding box associated with a portion of the multi-channel time-frequency domain array containing a signal with energy above a threshold level.
2. The system of claim 1 further comprising:
an identification process adapted to receive the bounded data set from the object detection block, to receive the multi-channel time-frequency domain array, and to extract a signal of interest from the multi-channel time-frequency domain array wherein the signal of interest is carried by the portion of the multi-channel time-frequency domain array within the bounding box.
3. The system of claim 1 wherein the noise reduction block comprises a transfer function block adapted to execute a transfer function on the multi-channel time frequency domain array.
4. The system of claim 3 wherein the transfer function is a double transform.
5. The system of claim 1 wherein the frequency range comprises a plurality of reduced bandwidth ranges; and
the transforming block comprises a plurality of transforming components wherein each of the plurality of transforming components is adapted to receive one of a plurality of reduced bandwidth datasets, wherein each of the plurality of reduced bandwidth datasets includes a portion of the single channel initial dataset corresponding to one of the plurality of reduced bandwidth ranges, wherein each of the plurality of transforming components is further adapted to convert its corresponding reduced bandwidth dataset from the time domain to a time-frequency domain and provide a corresponding channel of the multi-channel time-frequency domain array.
6. The system of claim 5 wherein the multi-channel time-frequency domain array comprises an aggregation of each of the channels provided by the plurality of transforming components.
7. The system of claim 5 wherein each of the channels of the multi-channel time-frequency domain array provided by each of the plurality of transforming components is time-aligned to each of the other channels of the multi-channel time-frequency domain array provided by each of the other plurality of transforming components.
8. The system of claim 5 wherein the transforming block further comprise:
a plurality of bandpass filters, each adapted to receive the initial dataset and provide one channel with a frequency range corresponding to a frequency range of one channel of the multi-channel time-frequency domain array.
9. The system of claim 5 wherein each of the plurality of transforming components comprises:
an analog to digital converter adapted to receive one channel with a frequency range corresponding to a frequency range of one channel of the multi-channel time-frequency domain array and provide a digitized dataset; and
a down converter adapted to receive the digitized dataset and provide a plurality of complex digital channels, wherein each of the plurality of complex digital channels comprises an in-phase portion and a quadrature-phase portion.
10. The system of claim 9 wherein each of the plurality of transforming components further comprises a frequency transformer adapted to receive one of either the in-phase portion or the quadrature-phase portion of each of the down converters and provide a channel in the time-frequency domain.
11. The system of claim 1 wherein the transforming block comprises a processor adapted to receive the multi-channel time-frequency domain array and apply an initial transform to each channel of the multi-channel time-frequency domain array at the same point over a specified length.
12. The system of claim 11 wherein each channel of the multi-channel time-frequency domain array is padded with at least one zero value prior to applying the initial transform.
13. The system of claim 11 wherein the initial transform is a Fourier transform.
14. The system of claim 1 wherein the object detection block is configured to divide the clean dataset into a plurality of histogram bins with each histogram bin having an energy level and the bounding box is defined to include all portions of the dataset included in a histogram bin having an energy level above the threshold level.