Noise Removal
FFT Engine
Noise Removal
The FFT Engine contains five different noise removal processes
Each method can be enabled individually
Click Removal
The click removal method operates on the time series data prior to the FFT calculation and therefore affects both output streams of the FFT Engine.
Click removal measures the standard deviation of the time series data and then multiplies the signal by a factor which increases rapidly for large signal components. This has the effect of reducing the magnitude of short duration transient signals such as echolocation clicks
Median Filter
Within each spectrogram slice, the median value about each point is taken and subtracted from that point.
Average Subtraction
A decaying average spectrogram is computed and subtracted from the current spectrogram value.
Gaussian Kernel Smoothing
The spectrogram is smoothed by convolving the image with a Gaussian smoothing kernel
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Thresholding
A threshold is applied and all data falling below that threshold set to 0.