How about a short computer vision lesson?
Take a look at the image below. Do you notice anything interesting?
An interesting question here is how to tell where the back side of the cup is relatively to the front. You may wonder what kind of people is interested in such questions. You! Every time you pick up a cup you need to know where the back is. Unless the material is transparent, you can’t see the holding place. So how can we do it? I discussed this with several hypothetical experts.
Database expert: Use barcode on the cup and store the size in a database.
- Assuming you have a full time DBA and a standards committee.
Physicist: Use a special wavelength and measure the scattering differences between the front and back sides, which should correlate with the size.
- Don’t try this at home.
Machine learning expert: Learn from examples. Collect enough images of glasses of known sizes, and use your favorite neural net / Boltzmann machine / support vector machine / belief propagation / Markov random field / singular value decomposition / decision trees. If nothing works try Gaussians with Bayes rule.
- Don’t forget to include Chinese cups in the training set.
Robotics expert: Just close the fingers until they touch the surface.
- Simple enough, but there are studies that filmed people grasping objects of different sizes, showing that the opening between the fingers already during the grasping motion are proportional to the final size, as if the brain executes a grasping plan where the size is estimated at the beginning.
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