How does one read from barcodes?

I would like to make a sweet iphone app that reads barcodes and generates a scene based on it. Anyone have any resources they can link me to or perhaps describe the process of their barcode implementation, just so that I'd开发者_JAVA百科 have a place to start? What kind of info is in a barcode?

Edit: Can I actually do anything with the barcode info? What's the size of the info on it?

I'll try and explain this...

Bar codes essentially translate to keyboard input. That is from your application's point of view, it would look like someone has entered some data via a keyboard.

Now in order to actually "read" the barcode, you typically need a barcode scanner. Of course these scanners work specifically with specific types of bar codes (1D and 2D bar codes). However, what you have on a cell phone is a camera and not a barcode scanner. So basically what you'll need is software that does the following

1. Takes picture of a barcode (that is the barcode is there in the picture somewhere)
2. Processes this image to "extract" the barcode information from it
3. Passes on this information to your application as if it were key strokes on a keyboard.

Nowadays you also have the concept of JPEG color barcodes. These are barcodes that look like colorful images. http://www.sersc.org/journals/IJSIP/vol2_no4/4.pdf

multi-format 1D/2D barcode image processing library for cell phones http://code.google.com/p/zxing/