Test Image
First, we made an ideal lowpass filter as shown:
Lowpass Filter =
[1 1 1]
1/9*[1 1 1]
[1 1 1]
Results of our lowpass filter
Notice how the lines are blurred and the words on the card and the phone are more difficult to read.
We then created an ideal highpass filter:
Highpass filter = [-1 1]
Results of our highpass filter
As you can see, there is a lot of "ringing" in this image, which gives the image an etched look.
We then performed used a different highpass filter on the original image.
New highpass filter =
[-1 -1 -1]
1/9*[-1 8 -1]
[-1 -1 -1]
Results of our new highpass filter
In this image we can see the edges in the image, but we didn't think
that it showed enough detail. We wanted
emphasize the detail in the image, so we performed a histogram stretch
and equalization on the image.
Results of Enhancing Highpass Filtered Image
In this image, you can see much more detail and more of the edges are shown.