Custom Captcha Widget for a Web Site

This project is to design a user friendly captcha program which will be very much similar in likeness to what the [login to view URL] use. However, I will need to be able to control how many letters and/or numbers, size, color, level of noise, etc. They need to be generated on the fly and without stored samples. Prior to committing yourself, please go see [login to view URL] and how their captcha is designed.