Daily Image

Click here or on the picture for a full size image.

Experiments in Face Recognition

Submitter: Minnie Mao, Jan Noordam
Description: Our business is Radio Aperture Synthesis, in which Fourier Transforms play an important role. Of course this is a very serious business, but in our lighter moments we sometimes play little games with the tools of our trade.

We started with regular images of two well-known JIVE leaders, whom we will call Bob and Alice, as is customary in this kind of demonstration. Both images were artificially blurred by removing the high spatial frequencies (i.e. the sharp features). The resulting fuzzy images, which only contain low spatial frequencies, were then subtracted from the originals to obtain images with only the sharp features(*). The six small images show the results.

The large hybrid image was then made by combining the high spatial frequencies of Bob (or Alice) with the low spatial frequencies of Alice (or Bob). We leave it to the reader to figure out which combination was actually used.

When you are close to the hybrid image, you can see the small details of the high-frequency components, and thus you recognize the person whose sharp features were used. But when you are further away, you are not sensitive to the high-frequency components so you recognize the one whose blurred image was used. Try it.

(*) In aperture synthesis, the sharp details are measured by the long baselines, while the short ones are sensitive to large fuzzy features. They are combined by means of the Fourier Transform.
Copyright: Minnie Mao,
  Follow us on Twitter
Please feel free to submit an image using the Submit page.