How Does My Digital Camera Work?

The other day in class, we mentioned that we use a lot of things and don't understand how most of them work. So I decided to be proactive and learn a little bit about some of my many gadgets. This is what I learned about my digital camera! Digital camera's work in the same way that a conventional camera does in that it uses lenses to focus light into an image, but instead of focusing light onto a piece of film digital cameras focus light onto a sensor that converts light into an electrical signal(1). This conversion is done mainly by one of two types of sensors: charge coupled device(CCD) or complimentary metal oxide semiconductor (CMOS). CCD are the most commonly used because they have been around longer and have a higher resolution. CCD image capturing is based solely on light intensity so color can not be detected. To add color to these images a color filter array(CFA) , a physical layer of color pigments that controls the intensity level of primary colors of light: red, green, and blue (2). These three colors must then be recombined to create the original color using a demosaicing algorithm that are calculated with a processor. Essentially the true color is never actually obtained but is guesstimated by averaging neighboring pixels together. The chemistry of the digital camera comes in the synthesis of the CFA filter. Many processes for synthesis of these CFA filters many involving charged polymers and cross linked mordant dyes.

References:

1.Nice K., Wilson T, and Gurevich G. How Stuff Work: Digital Cameras. Accessed April 13, 2009
2.Hirkawa K. and Wolfe P. Fourier Domain Display Color Filter Array Design. Harved University. Accessed April 13, 2009.
3.US Patent 4876167 - Color filter array containing a photocrosslinked polymeric mordant. Accessed April 13, 2009.