A team of engineers at the University of Wisconsin-Madison has prototyped a glass panel with handwriting recognition. Its peculiarity is that it is a purely passive system, in which there are no mechanisms or electronic components. The whole process takes place due to the special structure of the glass array and the operation of such "smart glass" does not require energy.
In fact, a narrowly targeted neural network is implemented inside the glass plate, which performs neuromorphic calculations at the speed of light, but in a limited range of values. In the example, these are numbers from 0 to 9 that need to be drawn on an illuminated platform, so that the light reflected from the points in the image then passes through the glass plate. Inside it contains many micron-sized lens bubbles that reflect light, plus tiny fragments of graphene that absorb light.
The whole secret is in the architecture of the internal structure of the plate, where the reflective and absorbing elements are arranged so that the light travels along a certain path. There are many of them, but of course. Each time we draw a certain line, pulses of light run through the inner labyrinth in order to exit at one of the points corresponding to the recognized digit. The more the original drawing looks like a number, the more pulses of light will pass along a suitable route through the glass and the more intense the glow at the exit at the desired point will be. That is why the authors of the development compare it with a neural network - instead of recognizing clear, fixed values, there is also a "learning" algorithm based on various images.
The obvious disadvantage of "smart glass" is that it cannot be adjusted during operation, it is a finished product with invariable properties. But this is also its advantage - imagine the "eye" of a robot car, which accurately distinguishes the colors of traffic lights, but costs a penny and works in almost any conditions. Or a lot of sensors in the skin of a combat vehicle, the work of which cannot be detected by an enemy sensor, because their activity is not manifested in any way. And already in the next version of "smart glass" its developers want to implement the face recognition function in order to make the same door lock that will not open the door to anyone except the owner.