Introduction of structured light and TOF in 3D face recognition technology

Nowadays, people can pay by brushing their faces when they consume, and several scenes in daily life such as security check, access control and attendance can be completed by brushing their faces, which is because of the application of face recognition technology. The face recognition technology is also used in smart phones, and in order to make the face recognition application have higher security performance, 3D face recognition technology is gradually applied. Scanmax shares with you what is the structured light technology and TOF in 3D face recognition technology, and what are the differences?

3D structured light technology

The basic principle of 3D structured light technology is that light with certain structural characteristics is projected onto the photographed object through a near-infrared laser, and then captured by an infrared camera. The light with structure will collect different image information because of different depth areas of the subject object, and then convert this change of structure into depth information through the computing unit, so as to get the 3D structure. In other words, the three-dimensional structure of the photographed object is obtained by optical means, and then the acquired information is applied in depth.

ToF ranging

TOF ranging, which can also be called LIDAR ranging method, is one of the solutions of 3D depth camera.ToF ranging has two kinds of single point and multi-point, and multi-point ranging is generally used in cell phones. The basic principle is that the laser source emits a certain field of view angle laser, and through a proprietary sensor, captures the flight time of near-infrared light from emission to reception to determine the distance of the object. In simple terms, a processed light is emitted and reflected back after encountering an object, capturing the time of the round trip, and the distance to the object can be calculated quickly and accurately by using the known speed of light and the wavelength of the modulated light.

3D structured light and ToF advantages and disadvantages summary

TOF technology has the advantages of faster response time, resistance to light, high accuracy of depth information, and long recognition distance, but also has the disadvantages of low resolution, high cost, high power consumption, and too large a module. The advantage of structured light technology is that it can be recognized in low light, higher resolution, and its cost and power consumption are moderate. The main disadvantage is that it is more susceptible to the influence of sunlight, short recognition distance, slightly slow corresponding time, etc.

Through the comparison of structured light technology and TOF technology, the application of 3D face recognition technology in smart phones, structured light technology has more advantages than TOF technology. In general, in the future, 3D face recognition technology will have more applications and bring more surprises to people.