With the development of technology, biometric technology has gradually entered our lives.TOF is the abbreviation of "time-of-flight". The TOF camera is a depth imaging camera. By emitting light to the target object and measuring the distance by measuring the transmission time between the lens and the object, the depth map is realized through multiple light rays and 3D three-dimensional depth sensing is achieved.Different types of TOF cameras use different light sources, including LEDs and lasers.TOF has been widely used in many industrial fields such as surveying and mapping, logistics, and unmanned driving. The solutions are mature and will play a role in more fields in the future.

ToF imaging technology emits continuous infrared at specific wavelengths to targets ray pulse, receive the light signal sent back by the object to be measured through a specific sensor, calculate the flight time or phase difference of the light round-trip to obtain the 3D depth information.TOFThe camera's brightness image and depth information can be connected through the model to quickly and accurately complete face matching and detection.

ToF workflow diagram 

TOF hardware compositions are:

Light-emitting unit: The light-emitting unit is usually a VSCEL that can emit specific wavelength infrared rays. VSCEL can emit higher signals at relatively small power.

Optical lenses and filters: used to collect reflected light.The filter only allows infrared rays of the corresponding wavelength to pass through, suppress other light and reduce noise.

Image sensor: The core component of the ToF camera receives reflected light and is responsible for measuring the time when each pixel point light is reflected from the light emitting element to the target object and then reflected back to the sensor.

The advantages of ToF

What is the difference between the structured light technology used by ToF and iPhone X, and what are its advantages?The structured light of iPhone X is to first use a laser to project the dot matrix or fixed pattern on the lens on the face, and then take an infrared image. Through the deformation of the dot matrix or image, the depth information is calculated, and then the face information is recognized.

Object depth of field infographic obtained by ToF 

ToF uses a special sensor to calculate the time of the emitted infrared laser back and forth to obtain the depth information of the subject, and then recognizes 3D information.

Different 3D imaging technology features