What the heck is ConvolveOp? (ImageSharpen Alternative)

A recent question on the adobe forums mentioned the ImageSharpen() function was adding a black border to the generated image. As google did not turn up much on the topic, I concluded most people are using alternate methods to sharpen images. A quick peek at some of the more popular image components confirmed it. These components all use java's ConvolveOp class, internally, for sharpening.

• Alagad Image Component
• ImageCFC
• ImageUtil.cfc

So what is ConvolveOp? This article gives a great explanation on how it works, why the border effect occurs and how to avoid it: Java 2D's ConvolveOp Class. If you are already using one of the components above, you probably do not have to worry about it. But if you are curious about how things work, the article makes a good read.