Entries from January 2007

I can reliably detect many simple targets and generate key events in real time using a web-cam and an ordinary piece of paper with printed targets. What are the important characteristics of the targets?

1. They must be meaningful to the user.
2. They must be detectable and easily distinguished from whatever will obscure them by the computer.
3. They must have an associated key, mouse or other event to control the computer.

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This page describes a little utility I wrote for my own use. If you want to use it, you can download it and its source. I don’t provide support but if you would like to report bugs you’ve found or changes you’ve made to it, I’d be happy to hear about it.

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Kelly’s engineer estimates beam thickness as 1/2 inch per foot of span.

I finally used the copy Camtasia Studio I bought to make a couple of short videos demonstrating computer vision methods. After setting the encoders up properly I got fine looking video and good audio in a 1 megabyte download.

For my video switch I want to be able to synthesize key events that look like they originated from the keyboard. The function SendInput in the user32.dll looks like the right low-level goods but Pete points out that the WScript.Shell has a SendKeys method that is easier to use. The Python code looks like:

import win32com.client
ws_shell = win32com.client.Dispatch("WScript.Shell")
SendKeys = ws_shell.SendKeys

DevGuru has a table of the key encodings.

I describe an idea for a simple and inexpensive tactile display and keyboard for Braille. The key simplification enabling this design is displaying Braille on six finger tips instead of as six tiny dots under one finger tip. The display is arranged in the same format as standard Braille embossers so users read and write in a reciprocal fashion. The display and keyboard might be useful for teaching Braille to blind children, as a communication system for deaf-blind people, and as a reading aid for blinded adults whose fingers are not sufficiently sensitive to read traditional Braille.

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I should investigate progress in simple face detection methods. These could be the basis of a simple head-switch.

Fast and efficient algorithm for face detection in colour images

Real Time Eye Tracking and Blink Detection with USB Cameras.

The facedetect demo in OpenCV looks useful.

CamTrack has similar goals, using the mean-shift algorithm. Thus page on CamShift looks useful. This one too. Object Tracking Using CamShift Algorithm and Multiple Quantized Feature Spaces

Head-tracking pointer at IBM looks interesting.

Efficient Face Tracking for User Interfaces

WATSON: Real-time Head Tracking and Gesture Recognition

Could be applied to lots of Linux apps. http://sourceforge.net/forum/message.php?msg_id=3874468

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Very interesting collection of posts on xpcom, mozilla, python, etc. over at BSBlog. I’d love to make the browser the platform for our applications for kids with disabilities. Sound is the key limitation. Should we do our own extension for sound?

TC sent this link to cheap Donkey Kong Bongos. If we can figure out how to interface to USB these could be cool for a music game.