"No two signatures--even ones penned by the same person-are exactly the same. But some characteristics, such as the writing direction and the way two lines overlap, will remain similar among many samples written by one individual. Traditionally, handwriting analysts have studied scrawls in two dimensions. Giuseppe Schirripa Spagnolo and his colleagues at the University of Rome Three in Italy, have turned up the heat. By scanning a document with laser beams, the team can generate a hologram of the pen strokes within a signature. "Using image processing and virtual reality makes it easy to detect the presence of bumps at crossover points," Schirripa Spagnolo says. "Finding these bumps allows experts to easily determine the sequence of strokes in a piece of handwriting and the telltale signs of a forgery or original."
But once the forgers know what this technique looks for, they will probabloy be able to beat it.