Last week the Word Lens iPhone app launched. It translates text between languages using the iPhone camera. You hold it up to a sign, menu or other piece of text and it replaces the text in the live video on screen with the translated text. It's fantastic. Take a look at the video below to see it working.

Word Lens is an example of Augmented Reality, where the real world is modified by computer-generated information. An example of this is graphics overlaid onto a football pitch during TV a TV broadcast. As a result of the dropping cost of cameras and easier computer vision, augmented reality has become common place in the past few years on mobile phones.

Most of these augmented reality apps exist either for novelty or advertising. Like iButterfly. You can see virtual butterflies flying around and can waft your phone around to 'catch' them. When caught the butterflies turn into a coupon.

What makes Word lens interesting is that it's a rare example of Practical AR. Another would be DanKam, which lets colourblind people see the difference between similar colours more clearly. There's a more full explanation on their blog.

Finally there's Sudoku Grab which can scan in an image of a sudoku grid and solve it on your phone

Hopefully we shall see more examples of practical AR in the future.