Filter of Your Choice

Next, you will choose your own filter to implement! You can choose from one of the following, or make up your own. As previously discussed, for each filter, keep the original image for reference, copy it, and then apply the filter to the copy.

Blur

When you blur an image, you set the color of each pixel to be the average of the 9 pixels in the 3 x 3 square centered at that pixel (i.e., the average of the original pixel and its original 8 neighbors). Be careful at the edges of the image: not all pixels have 8 neighbors!

Posterize

A typical pixel can have one of 256 values for each color channel. In a posterized image, this number is drastically decreased. Each color channel value should be rounded to the nearest multiple of 64.

Contrast

When increasing the contrast, color values at 128 should be unchanged. For any other value val, the difference between val and 128 should be scaled a factor of two. For example, a color value of 129 (1 above 128) would become 130 (2 above 128). 125 (3 below 128) would become 122 (6 below 128). Just remember that you’ll need to stay between 0 and 255.

Add your filter of choice to the menu and test it out!