how camera phones work

Taking the Picture

The camera in a camera phone is similar to a webcam. There is a small CMOS or CCD sensor behind a lens, capable of capturing images and converting them into digital data.

Once the picture has been taken, it is stored in the camera phone's flash memory, where it can be viewed on the camera phone's screen. Like most digital cameras, the majority of camera phones use JPEG image compression to reduce the file size of the picture and save on memory. This also helps to reduce the 'cost' of transmitting the picture, since there is less data to send.

Sending the Picture

The next step is to prepare the picture for transmission. This is where software comes into play. Every camera phone on the market today comes preloaded with a messaging application. This application allows the user to compose a message, address it to either another phone or an e-mail address, and attach a picture from the phone's memory. The protocol, or standard, that this message follows is the evolving Multimedia Messaging Service (MMS) standard. Essentially, this is the natural successor to the original Short Messaging Service (SMS) protocol for sending text messages back and forth between cell phones as well as some instant messaging (IM) PC users.

The problem with the current state of the MMS standard is similar to the problems that faced the first SMS users. Since there is no way for the sending phone to know what the receiving device is or what it is capable of, messages are formatted according to a format that the network operator understands, and the message is sent to the network operator's MMS server.

Once the message has been received by the MMS server in the network operator's network, it is reformatted according to the needs of the receiving device. For example, if the MMS is being sent to an e-mail address, the MMS message is converted into a format that conforms to e-mail protocols. If the message is going to a phone user who does not have a MMS-capable phone, then the message is redirected to a web server, and the recipient receives a SMS with a URL for the website where they can pick up their message (using a computer).

Receiving the Picture

Once the message has been properly formatted, it is sent through to the recipient. If the recipient is a MMS-capable phone, the software application on the phone opens up the message, and displays the attached picture. Note that the recipient does not need to be a camera phone, it only needs to be capable of receiving a MMS message and displaying the picture attachment