Mike Perkins

Transforms for Video Compression, Part 3: The DCT and Why Transforming Is Valuable

The use of transforms in data compression algorithms is at least 40 years old. The goal of this three-part series of posts is to provide the mathematical background necessary for understanding transforms and to explain why they are a valuable part of many compression algorithms. I?m focusing on video since that?s my particular interest. Part…

Cross Processing Images in the Gimp

Color film photography looks to be fading fast; recently the last rolls of Kodachrome film were developed by the last place in the world that can process it. While black and white film developing is commonly done in home laboratories, color film development requires specialized chemicals that were usually only available on an industrial scale.…

Mike Perkins

Transforms for Video Compression, Part 1: Vectors, the Dot Product and Orthonormal Bases

The use of transforms in data compression algorithms is at least 40 years old. The goal of this three-part series of posts is to provide the mathematical background necessary for understanding transforms and to explain why they are a valuable part of many compression algorithms. I?ll focus on video since that?s my particular interest. Part…

Creating the Orton Effect in Gimp

Recently I decided to learn how to write scripts in the Gimp image editing program to automate certain tasks. The first task I wanted to automate was the Orton effect. This is an effect invented by Michael Orton in the 1990?s, which consists of taking two copies of an image, one blurred, and one sharp,…

Detecting Well-Focused Images

Recently, one of my colleagues mentioned to me that he takes large numbers of pictures and wanted to write a program to automatically determine which was in the best focus, out of a group of pictures that were taken of the same scene. He mentioned that he expected the algorithm to be computationally intensive. My…