The Savitzky-Golay smoothing filter
was employed for smoothing the image and for computing the numerical derivatives.
The expression of the smoothing filter
as defined in DO-253C  is
In order to reduce as much noise as possible without impairing loss in the original signal information due to elimination of important frequencies a use of a classic filter may be insufficient, and that's because it requires a polynomial smoothing filter
such as the Savitzky-Golay filter.
A Gaussian Smoothing filter
is a low pass frequency filter.
Since the convolution operation is associative, we can convolve the Gaussian smoothing filter
with the Laplacian filter first of all, and then convolve this hybrid filter with the image to achieve the required result.
Setting amplitude limits on the graph is also easer as is the selection of gate times and smoothing filter
for the frequency-domain graphs.
A broad Savitzky-Golay smoothing filter
is first applied to the measured spectra to identify the broad variations and smooth out the relatively narrow analyte features.
Similar results were obtained for the case of smoothing filter
shown on Fig.
With its system-on-a-chip architecture, ISD's MicroTAD-16M integrates an on-chip oscillator, anti-aliasing filter, smoothing filter
, AutoMute(TM) noise suppression, audio amplifier, and high density multi-level Flash storage array into one easy-to-use chip.
This paper presents a comparison between different techniques of noise removal such as NL-means algorithm, local smoothing filters
, bilateral filtering, wavelet thresholding and median filtering, based on current researches.
But gradient based determining of ridge orientation can also be inefficient because of inexpressive edges of ridges and valleys, since we smooth ridge and valley structures with smoothing filters
in the pre-processing step.
12) The results for sensitivity, accuracy and negative predictive values were better for the enhancement filter (Sharpen 3 x 3) than the smoothing filters
(S9, Smooth and Smooth 3 x 3), also used.