Unsharp Masking; Median Filter; Fix Hot Pixels; Fix Cold Pixels - Meade Autostar Software Manual

The Normal button constructs a filter that does not alter the original image when the convolution process
is started. This allows you to reset the kernel to a normal starting point when you are constructing your
own kernels.
The Smooth button builds a kernel that subtly blurs the image, reducing the effect of any noise that may
be present in the image. Lowering the value of the center number in the kernel increases the smoothing
effect. While increasing the value reduces the effect.
The Sharpen button is useful in bringing out the details in images that originally appear somewhat blurred.
This effect is different than Unsharp Masking, but can appear similar in some images.
The Edge Enhance and Edge Only kernels are quite similar except for the value at the center of the
kernel. Their effect is to enhance the appearance of any edges (transitions) from light to dark. The Edge
Enhance maintains the overall appearance of the image, but modifies the edges, while the Edge Only
filter displays only the edge modifications.
The Average button merely sets all of the kernel values to 1.0 resulting in a 5x5 pixel average (blurring) of
the image. The Clear button sets all the values to 0.0. This can be used to set the starting values in your
own custom filter.
To Preview the effect of your filter on the image, click the preview button. Adjust the parameter until you
achieve the desired effect, then click OK.

Unsharp masking

This powerful command allows you to bring out the subtle detail that is normally not visible in the
unprocessed image. When this command is selected, the Unsharp Masking dialog box is displayed.
This allows you to set the region size used to produce the blurred unsharp mask. The larger the region
size, the more unsharp (blurrier) the resulting mask becomes. This allows details smaller than the region
to be enhanced after the mask and the image are merged.
You can try other values for the Scale Factors to increase or decrease the effect of the unsharp masking
technique. The only requirement is that the value for the image must be 1 greater than the value for the
mask. Try values such as: 5,4 or 6,5 to increase the effect, or 2,1 to decrease the effect.
NOTE: The original values of the Scale Factors are left untouched.

Median Filter

Median filtering modifies an image by replacing each pixel with the median (middle value) of it and all of its
neighboring pixels. It is useful for removing random noise, and some column defects. Works on single
pixel artifacts and smoothing out a generally noisy image.

Fix Hot Pixels

Even after calibration, images often have individual pixels that are too bright. These can be a result of
read noise from your camera, cosmic rays that hit your imager during the exposures, slight errors in your
calibration images. Regardless of the cause, this filter will look for these single pixel anomalies and
remove them. When you select this command, a dialog box will appear. This dialog allows you to set how
aggressively the program hunts for bad pixels. The smaller the threshold number you supply, the more
aggressively, the filter will act.

Fix Cold Pixels

Even after calibration, images often have individual pixels that are too dark. These can be a result of read
noise from your camera, cosmic rays that hit contaminated your dark frams, slight errors in your
calibration images. Regardless of the cause, this filter will look for these single pixel anomalies and
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