Systems and methods for noise reduction in imaging
Systems and methods are provided for the denoising of images in the presence of broadband noise based on the detection and/or estimation of in-band noise. According to various example embodiments, an estimate of broadband noise that lies within the imaging band is made by detecting or characterizing the out-of-band noise that lies outside of the imaging band. This estimated in-band noise may be employed for denoise the detected imaging waveform. According to other example embodiments, a reference receive circuit that is sensitive to noise within the imaging band, but is isolated from the imaging energy, may be employed to detect and/or characterize the noise within the imaging band. The estimated reference noise may be employed to denoise the detected in-band imaging waveform.
1. A method of denoising imaging signals detected in the presence of noise, the method comprising:
detecting imaging signals with an imaging transducer receive circuit along a plurality of spatially consecutive scan lines, thereby obtaining a plurality of imaging waveforms, each imaging waveform corresponding to a respective scan line;
filtering each imaging waveform to generate a respective in-band imaging waveform residing within an imaging band and a respective out-of-band noise-detection imaging waveform residing within a noise-detection band that lies, at least in part, beyond the imaging band;
segmenting each in-band imaging waveform and each out-of-band noise-detection imaging waveform according to a series of time windows;
processing a windowed portion of the out-of-band noise-detection imaging waveform corresponding to a selected scan line of the plurality of spatially consecutive scan lines and determining that a denoising correction should be applied to a corresponding windowed portion of the in-band imaging waveform;
calculating the denoising correction based on one or more statistical measures associated with corresponding windowed portions of in-band imaging waveforms from two or more of the spatially consecutive scan lines;
applying the denoising correction to the windowed portion of the in-band imaging waveform; and
generating an image based on denoised in-band imaging waveforms respectively associated with the plurality of spatially consecutive scan lines.
2. The method according to claim 1 wherein the denoising correction is determined, on a per-sample basis within the windowed portion of the in-band imaging waveform corresponding to the selected scan line, and wherein the one or more statistical measures are generated, on a per-sample basis, by processing sample values within the corresponding windowed portions of the in-band imaging waveforms from the two or more spatially consecutive scan lines.
3. The method according to claim 2 wherein the one or more statistical measures comprise an average and a minimum.
4. The method according to claim 1 wherein the imaging transducer receive circuit comprises an ultrasound transducer.
5. A method of denoising imaging signals detected in the presence of noise, the method comprising:
detecting imaging signals with an imaging transducer receive circuit along a plurality of spatially consecutive scan lines, thereby obtaining a plurality of imaging waveforms, each imaging waveform corresponding to a respective scan line;
concurrently, for each scan line, detecting noise with a reference receive circuit configured to avoid transduction of imaging energy while detecting noise received by the imaging transducer receive circuit, thereby obtaining a set of reference noise-detection waveforms, each reference noise-detection waveform corresponding to a respective imaging waveform;
filtering each imaging waveform to generate a respective in-band imaging waveform residing within an imaging band;
segmenting each in-band imaging waveform and each reference noise-detection waveform according to a series of time windows;
processing a windowed portion of the reference noise-detection waveform corresponding to a selected scan line of the plurality of spatially consecutive scan lines and determining that a denoising correction should be applied to a corresponding windowed portion of the in-band imaging waveform;
calculating the denoising correction based on one or more statistical measures associated with corresponding windowed portions of in-band imaging waveforms from two or more of the spatially consecutive scan lines;
applying the denoising correction to the windowed portion of the in-band imaging waveform; and
generating an image based on denoised in-band imaging waveforms respectively associated with the plurality of spatially consecutive scan lines.
6. The method according to claim 5 wherein the denoising correction is determined, on a per-sample basis within the windowed portion of the in-band imaging waveform corresponding to the selected scan line, and wherein the one or more statistical measures are generated, on a per-sample basis, by processing sample values within the corresponding windowed portions of the in-band imaging waveforms from the two or more spatially consecutive scan lines.
7. The method according to claim 5 wherein the one or more statistical measures comprise an average and a minimum.
8. The method according to claim 5 wherein the imaging transducer receive circuit comprises an ultrasound transducer.
9. The method according to claim 5 wherein the reference receive circuit comprises a de-activated imaging transducer that is configured to lack sensitivity to imaging energy.
10. The method according to claim 5 wherein the reference receive circuit comprises one or more circuit components capable of detecting noise while lacking sensitivity to imaging energy.