Fun with a webcam



Introduction

When I was a child, I wished I had a video camera to play with. Now that I finally own a webam, I decided to do fun things with it.

I dont use my webcam to do videoconference... And I would really appreciate if someone could explain why we call them Webcams? What's the link between the web and an USB camera?

If you have done cool projects using your webcam too and would like me to link to your page or add an entry on this page, please contact me. If you saw a related page or know a page about any cool webcam project, please contact me. I'll add them to the Other people's projects section.

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Photography

Before I got my digital camera, I used my webcam a lot to take pictures. The picture quality is of course not as good as with a decent digital camera, but it's still acceptable for a web site.


Here are some pictures I took of my lab in november 2003:

It's also possible (at least with this model) to take close pictures of objects:

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Noise reduction

In low light conditions, some noise appears in the pictures. Unlike the light coming from the objects we are trying to photography, the noise is random. Being random, it tends to cancel itself when we do an average of many pictures (several seconds).

Another problem that occurs in low light is that the contrast is very low. We can "stretch" the contrast so that the less bright pixel becomes black (0) and the brightest pixel is full white (255). We do the same for all three color channels (Red, Green and Blue).

I wrote a tool to experiment with those principles. Here is a good example:


From left to right 1) The picture from the webcam as-is. 2) The same picture with contrast stretched. 3) Average of several images. What you are seeing is an IBM paper package.

The software I wrote evolved into a fun tool to play with video coming from a webcam. It now has many other kind of filters. I called it SDLcam.

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Infra-red

I discovered that my webcam is able to see infra-reds. This means that it's possible bright something using infra-reds in order to take a picture in darkness (at least for our eyes).

The picture on the left, containing 27 infra-red leds, confirms that the webcam is sensitive to infra-reds. The central picture shows the Atari 1040STe computer I'm about to photograpy. The picture on the right is the result. My noise reduction system was necessary to obtain this result.


Here is another proof that the webcam sees infra-reds. My pupil is quite dilated:


A visitor mailed me about an article where someone explains how to remove the IR filter of the webcam to obtain a higher IR response. I will try this soon!
http://homepage.ntlworld.com/geoff.johnson2/IR/

Here is another site where this time a camera phone gets modified for IR: Hacking a SE T610 camera for IR
A friend has sent me 2 pictures demonstrating the ability to view under ink using an ir-modified webcam.
Picture taken with a normal webcam.
Picture taken with a webcam modified for infra-red only.

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Monitoring

Sometimes I use my webcam as a security camera.
With the help of a tool called motion, it is possible to automatically save pictures containing motion. It's also possible to connect to the built-in web server to see in real-time what's going on in front of the camera.

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Lightning pictures

Using motion, which saves pictures containing motion (In other words, when a new picture is different enough from the previous one, it is saved), I was able to take many pictures of the lightnings during a storm: (Easy, start motion and wait :)

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Wide angle lens

The lens used by my webcam is designed assuming that the camera will be on top of a screen adn that it should only see the face of the person sitting in front of it. This means that it does not have a very wide angle of vision. Because of that, to photography large objects using my webcam I must be far from the object.

In security applications, we often want to see a full room. This is impossible with the default lens.

I found a way to increase the angle of vision of the webcam using a door viewer. I simply installed the door viewer in front of the webcam. I obtained a wide angle of vision, but the image is small.

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Telescope

It's possible to install the webcam in front of a telescope's eyepiece in order to take pictures.

Here are some pictures I took of the moon:

You may also look to windows in your neighborhood: (But this is not very nice)

Someone wrote me a about a website explaining how to use lens for 35 mm cameras to build a webcam telescope.
http://www.dennisonbertram.com/hackmaster/2005/02/webcam-telescope.htm

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Microscope

To take pictures with a microscope, I removed the lens from the webcam and the microscope's eyepiece. With this setup, the picture coming from the microscope goes directly to the camera's sensor.

I used hot glue to stick the webcam to the microscope since it's easy to remove:


Here is a picture of microscopic crystals taken with this setup:


For more pictures, visit my mysterious green crystals page.

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360 degrees

With a step motor (stepper) controlled by a parallel port, I built a platform which can rorate an object step by step, taking a picture of each step automatically.

Here is an animation built with this: (I has less frames than the original and is smaller)


I also wrote a program that's able to "unroll" objects. The stepper does a full revolution in 200 steps. At each step, the program saves the central line of the picture received from the webcam. Next, each of the saved lines are aligned one after another, from left to right, forming an image.


First of all, we must align the webcam on the object's rotation axis:
After 200 steps, the picture looks like this:

The image ratio is wrong. I would need a mecanism with some gears to obtain more steps per turn. Meanwhile, I can cheat by resizing the image:

It's fun to try to "unroll" non-circular objects: (in this example, it's a pager)

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Computer control with laser pointer

I wrote a simple program that uses a webcam to detect the presence and position of the spot created by a laser pointer on a wall.

It is possible to define hotspots which can be activated using the pointer. When a hotspot is activated, any command can be executed. My goal was to control a music player, xmms, with this system.

For more information, visit Software > laserspotcam

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Other people's projects / links

In this section, I'll add links to other fun or innovative uses of webcams.

OvO is a commercial game (with free demo version) which you control with your webcam: www.ovogame.com

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Copyright © 2002-2014, Raphaël Assénat
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