Image Processing Lab
Lab 3
Bryan Evenson and Ted Gould
    In this lab, we played with some lowpass and highpass filters.  We used the image below for our tests.

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.