Advantages & Disadvantages of TOF (Time of Flight )Technology

1. TOF (Time of Flight) principle: When a laser emitter emits light pulses, the light will reflect when it meets an object. The light captured by the lens is the flight time. The distance between the object and the lens can be judged by simple formula calculation (Figure 1)

TOF Technology
2: TOF element: the main element consists of three parts: light source (laser emitter here), lens and photosensitive element（ (Figure 2)

TOF Technology Advantages

First, the working distance is long, and the effective real-time depth information within 5m can be obtained;

Second, it can be used in a wide range of scenes, no matter whether the subject has feature points or not, whether the ambient light is strong (such as sunlight) or weak, it can obtain effective depth of field information;

Third, it has high precision in long distance. The absolute precision of TOF between the mobile phone and the subject, that is, the relative precision between the subject, can reach the level of centimeter.

TOF Disadvantages

  • Resolution of the mainstream TOF sensors available on mobile phones is relatively low (180 * 240, 240 * 320, 240 * 480, etc.), so the accuracy and X / y resolution in close range will be relatively low. If you are interested, you can know the accuracy of the front structured light by yourself;
  • The power consumption and calorific value of the components are relatively large when they are working, and good heat dissipation conditions are needed for long-time work, and the use of the components in consumer electronic equipment needs to be continuously optimized;
  • Currently, the solution based on TOF is not fully mature, the corresponding content production and development groups are relatively weak, and the supporting application scenarios are few.
  • TOF detection angle <60 degrees. So TOF cameras must keep enough high entrance.

TOF Cameras for People Counting

TOF is the top accurate people counting solution in high entrance, especially in the malls and super market. However, in the transit bus passenger counting, the detection distance from camera to passenger heads, usually very short <20cm. So TOF is not good at bus environment.