Some supermarkets make you weigh the fruits or vegetables you buy and put the printed sticker with the final price on the bag. A new scale developed by a German Fraunhofer institute contracted by Mettler-Toledo is automatically finding out what you kind of fruit or vegetable you have put on it.

The smart supermarket scale uses a camera and image processing to detect if you have bought kiwis or oranges.
The scale's image processing is even working through semi-transparent bags and also is able to differentiate between various kinds of the same fruit. This is quite remarkable if you think about Apples and how similar the different kinds can be. Additionally fruits can be in different states of ripeness.

The scale displays what it thinks you put on a touchscreen, where the customer can confirm the selection.
The smart scale is currently tested in 300 supermarkets across Europe.
More details on Heise (German). Photo shows a Mettler-Toledo scale with touchscreen (site).

Update:
IBM has developed the basic technology for this kind of scale already 10 years ago. The company sold the technology to Mettler-Toledo, but still holds patents. See also this IBM page about Veggie Vision. (Thanks Jonathan C.).

There are also lots of supermarkets where the cashier is weighing your produce purchases. If you buy something a bit out of the ordinary they always have to look it up in their map, which can take quite a while. The smart scale camera system could also find its use at cash registers next to the bar code scanner.