Each drive microsteps to 25,000 steps/rev with a 1.8[degrees] step motor (1/125 step) even when command pulses are low resolution-thanks to the proprietary step smoothing filter
. Users can set up drive parameters- including motor selection, current, and step resolution-using dip or rotary switches.
Figure 2 shows the actual motor speed and Kalman Filter and smoothing filter
estimated speed and their zoomed response.
. The velocity traces of both the head and eye contain small ripples, which possibly influence on the gain calculation and saccade detection.
Bi Lateral filtering is a simple, non-linear, edge preserving and noise reducing smoothing filter
Bilateral filtering  is the most intuitive nonlinear smoothing filter
, although it suffers from the gradient inversion effect, which uses a histogram-based approximation to calculate the weight, and it is computationally complex.
Caption: FIGURE 4: Comparison of different image smoothing filter
and their corresponding segmentation results.
The expression of the smoothing filter
as defined in DO-253C  is
Filters that are commonly used on SPECT imaging are the Ramp filter, a high pass filter eliminating the star artifact and blurring, the Hanning filter, a low pass smoothing filter
, the Hamming filter, also a low pass smoothing filter
having a different amplitude at the cutoff frequency, the Butterworth filter, which both smoothers noise and preserves the image resolution, the Parzen filter, the most smoothing low pass filter, and the Shepp-Logan filter, which is the least smoothing but has the highest resolution .
The visual experiments illustrate that the proposed FHD algorithm achieves the maximum PSNR value over Gaussian smoothing filter
and Wiener filter, although the PSNR rate is slightly higher than Gaussian filter and Wiener filter.
The S9 filter (a smoothing filter
) acts uniformly, calculating an average value for a group of pixels, and redistributing the density mean among the pixels, resulting in an image that has more uniform gray tones and is less granular.