Creative Outbursts

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Java / Processing / OpenCV: camera trigger

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For many applications in behavioral biology, it's nice to trigger events or devices (e.g. cameras, lights) when an animal moves into a specific region of a camera view. In order to trigger our lab's high-speed video cameras, I wrote a simple program in the Java language that uses an inexpensive web-cam to detect if objects move from one frame to the next. A region of interest can be set by clicking and dragging to position a red rectangle on the camera view. Thresholds can be changed to make the trigger more or less sensitive, and it can be toggled between an "armed" and "unarmed" mode.

Making stuff: bend sensor

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When exploring sensors for reading out behavioral (i.e. motor) output from an animal, I came across bend sensors that can be incorporated into clothing ( By using thin copper foil, velostat, and epoxy, I was able to shrink the dimensions of the sensor to about 15 mm length. Unfortunatly, I needed something even smaller, and something more compliant. But here's the basic idea:

Processing: 2D Waviness

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Beyond sine waves: Perlin noise, images, and, yes, (pixel-based) sinusoids

My second attempt at creating a moving sine wave is somewhat different than in the first example. This time, I created a sine wave class, which during initialization creates an array holding the pixel values of a sine wave. I also added a Perlin noise class, for making a 2D noise pattern, as well as an image class to load an images.

High-Speed video: Butterflies dancing

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The sequence below was shot in the butterfly house of the Pacific Science Center in Seattle in 2010.

Filmed at 500 fps. This video consists of about 730 frames, which means the whole sequence took less than 1-½ seconds in real time. Shot with a Phantom Miro 4 color high-speed camera, which was graciously loaned to the Daniel Lab by its manufacturer, Vision Research.


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