# Peter Yu

Peter Yu is a research and development professional with expertise in image processing, remote sensing and computer vision. With an educational background in systems design engineering and considerable research and development experience in industries ranging from district energy systems to medical imaging to cinematic visual effects, he is always looking for interesting problems to solve with significant real-world applications. This is his personal website where you can learn about his research, see some of the 3D and CG artwork that he works on in his spare time and read some helpful tutorials he has written. → More about Peter

Email: [user]@[host] where [user]=web and [host]=peteryu.ca

## New and Updated Pages

### Plot sunrise and sunset times in MATLAB or Octave

Winter is coming and so is summer (in the other hemisphere of the world). The length of the days are changing and combined with daylight saving time, you might want to know just when you get to see the sun again. This tutorial shows you how to make a graph that plots the sunrise and sunset times in MATLAB or Octave. You'll learn how to shade the area above, below and between curves, use date and time formatted axis tick labels and draw grid lines for each tick mark in a custom colour. The result will look like this:

This code works in Octave but it should be compatible with MATLAB, which I don't have access to at the moment.

### LaTeX script styles for math

When I was writing a paper, I needed a lot of mathematical variables. I had already used up so many letters in both plain text and bold face that I needed more styles for English letters. So I looked for ways of using different types of script styles in LaTeX equations. I already knew about \mathcal, which is used for math calligraphy but it only supports upper case letters when I really needed lower case variables. It turns out that a lot of the script styles in math mode are upper case only. I eventually found several ways of using lower case script letters in LaTeX equations, as well as a few other math mode styles that seem useful. I have listed them in this short tutorial.

2012/09/05 21:23 · · 1 Comment

### Using Grep

This page is where I consolidate all my notes on the grep tool, which is available on Linux and Unix, and also on Windows as part of Cygwin. I usually use it on Cygwin, so these notes apply to that version of grep.

2012/04/02 22:08 · · 0 Comments

### LightWave surfaces with the node editor

The nodal surfaces in LightWave are pretty neat and allow for some complex surfaces to be made. Surfacing like this is still quite new to me so I am going to start documenting the node set up for some surfaces here on this page. There probably will not be too many surfaces here (not enough time for 3D!) but I will add to it from time to time.

2012/01/21 14:15 · · 2 Comments

### Track changes and highlight revisions in LaTeX documents with latexdiff

When several authors are editing a paper, it is sometimes necessary to quickly highlight what changes have been made in a particular version of the paper compared to previous versions. Word processors have long had revision tracking features for this but some LaTeX authors are unaware that there is a handy utility called latexdiff that can also highlight changes between two revisions by comparing two LaTeX documents:

2012/08/12 22:22 · · 4 Comments

About Peter Yu I am a research and development professional with expertise in the areas of image processing, remote sensing and computer vision. I received BASc and MASc degrees in Systems Design Engineering at the University of Waterloo. My working experience covers industries ranging from district energy to medical imaging to cinematic visual effects. I like to dabble in 3D artwork, I enjoy cycling recreationally and I am interested in sustainable technology. More about me...

Feel free to contact me with any questions about this site at [user]@[host] where [user]=web and [host]=peteryu.ca