An induced vibration dynamic touch sensor comprises a compliant membrane adapted for sliding contact with an object so as to induce vibrations in the membrane, and a transducer assembly for converting the vibrations into electrical signals. The electrical signals are processed to produce a normalized spectral signature characteristic of the size and shape of the object, and the sizes and shapes and nature of its surface features. A pattern vector is extracted from the spectral signature and subjected to discriminant analysis to classify and recognize the object. The invention is capable of discriminating between objects differing in diameter by as little as 1/32 inches and differing in spacing by as little as 0.01 inches.