Many individuals are accustomed to facial recognition systems that unlock smartphones and game systems or allow access to our bank accounts online. But the present technology can require boxy projectors and lenses. Now, researchers report in ACS’ Nano Letters a sleeker 3D surface imaging system with flatter, simplified optics. In proof-of-concept demonstrations, the brand new system recognized the face of Michelangelo’s David just in addition to an existing smartphone system.
3D surface imaging is a typical tool utilized in smartphone facial recognition, in addition to in computer vision and autonomous driving. These systems typically consist of a dot projector that accommodates multiple components: a laser, lenses, a lightweight guide and a diffractive optical element (DOE). The DOE is a special sort of lens that breaks the laser beam into an array of about 32,000 infrared dots. So, when an individual looks at a locked screen, the facial recognition system projects an array of dots onto most of their face, and the device’s camera reads the pattern created to substantiate the identity. Nevertheless, dot projector systems are relatively large for small devices similar to smartphones. So, Yu-Heng Hong, Hao-Chung Kuo, Yao-Wei Huang and colleagues got down to develop a more compact facial recognition system that will be nearly flat and require less energy to operate.
To do that, the researchers replaced a conventional dot projector with a low-power laser and a flat gallium arsenide surface, significantly reducing the imaging device’s size and power consumption. They etched the highest of this thin metallic surface with a nanopillar pattern, which creates a metasurface that scatters light because it passes through the fabric. On this prototype, the low-powered laser light scatters into 45,700 infrared dots which are projected onto an object or face positioned in front of the sunshine source. Just like the dot projector system, the brand new system incorporates a camera to read the patterns that the infrared dots created.
In tests of the prototype, the system accurately identified a 3D replica of Michelangelo’s David by comparing the infrared dot patterns to online photos of the famous statue. Notably, it completed this using five to 10 times less power and on a platform with a surface area about 230 times smaller than a typical dot-projector system. The researchers say their prototype demonstrates the usefulness of metasurfaces for effective small-scale low-power imaging solutions for facial recognition, robotics and prolonged reality.
The authors acknowledge funding from Hon Hai Precision Industry, the National Science and Technology Council in Taiwan, and the Ministry of Education in Taiwan.
