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It is believed that few people will pay too much attention to the sensor function on their mobile phones. However, the TOF technology frequently appeared in the PPT of the new mobile phone launch event recently has really caught everyone's attention. Maybe you are not impressed with TOF, but you may have some understanding of the previously popular emojis changing with the facial expressions. As one of the mainstream solutions for 3D sensing, TOF technology is now not only widely used in mobile devices, but also emerging in intelligent projection.
So what is TOF? What is the purpose and principle of using TOF technology in projectors?
First of all, TOF is short for Time of Flight. TOF camera consists of light source, light source, optical components, sensors, control circuit and the processing circuit and so on several units, with the ordinary machine vision imaging is roughly similar, its basic principle is through the continuous emission light pulses (generally invisible light) as objects to be observed, and then use the sensor to receive the return from the object light, by detecting the light pulse flight (round-trip) time to get the target distance. In simple terms, the distance is obtained by emitting a pulse of light that detects the time difference between the incident and the reflected light. According to its basic principle, TOF technology has the characteristics of real-time sensing, measurement accuracy and error fixation, strong anti-interference ability and so on.
After having a basic understanding of TOF technology, the principle and functions that can be realized in the application of TOF in the projector will be clear at a glance. Here, taking dangbei F1C as an example, dangbei F1C is equipped with two-channel laser TOF technology, which realizes the functions of automatic non-inductive focusing and automatic trapezoidal correction. Those of you who have used projectors should know that focusing and trapezoidal correction of projectors have always been pain points in the user experience. Now that both functions can be fully automated, the user experience will naturally improve.
How do you do that? Let's start with autofocus. TOF technology is often used in three categories: one is for people, such as face recognition; the other is for objects, such as sweeper to avoid obstacles; the third is for focusing, whether it is camera module or projector, it is a kind of focusing. By using the features of real-time sensing and measurement error fixation of TOF technology, the measurement accuracy will not decrease with the increase of the measurement distance. When the screen blurs in the projection play or the virtual focus caused by projection displacement will be monitored and finally calibrated in real time, so as to achieve the effect of real-time autofocus.
The geometric relationships between a trapezoidal correction is more complex, based on the optical properties of the projector, when plane and projector can placed vertically with each other, the projection surface will present trapezoid image, the current in the vertical direction of the trapezoidal automatic correction technology is mature, built-in gravity sensor can, but in horizontal direction of the existing sensor can't perceive level Angle change. Using TOF technology can be faster and more accurate real-time location, the perception of horizontal plane Angle changes. Still when becks F1C, for example, the configuration of dual laser TOF technology, using TOF range around the projection distance measuring module, combined with the Angle of projection light machine information and dual laser ranging module Angle, through the calculation of geometric mathematical relationship between trapezoidal variation, needed to define the parameters of the trapezoidal correction value to correct image. Therefore, by rotating the projection Angle at will, TOF technology can send back the data in real time, and then through the calculation and processing of the built-in chip, finally realize the "positive" screen display of any Angle.
TOF has become a mainstream 3D sensing solution due to its small module size, relatively low cost and excellent real-time sensing capability. Since it can be popular in the mobile phone field, it can also play an increasingly important role in projection.
So what is TOF? What is the purpose and principle of using TOF technology in projectors?
First of all, TOF is short for Time of Flight. TOF camera consists of light source, light source, optical components, sensors, control circuit and the processing circuit and so on several units, with the ordinary machine vision imaging is roughly similar, its basic principle is through the continuous emission light pulses (generally invisible light) as objects to be observed, and then use the sensor to receive the return from the object light, by detecting the light pulse flight (round-trip) time to get the target distance. In simple terms, the distance is obtained by emitting a pulse of light that detects the time difference between the incident and the reflected light. According to its basic principle, TOF technology has the characteristics of real-time sensing, measurement accuracy and error fixation, strong anti-interference ability and so on.
After having a basic understanding of TOF technology, the principle and functions that can be realized in the application of TOF in the projector will be clear at a glance. Here, taking dangbei F1C as an example, dangbei F1C is equipped with two-channel laser TOF technology, which realizes the functions of automatic non-inductive focusing and automatic trapezoidal correction. Those of you who have used projectors should know that focusing and trapezoidal correction of projectors have always been pain points in the user experience. Now that both functions can be fully automated, the user experience will naturally improve.
How do you do that? Let's start with autofocus. TOF technology is often used in three categories: one is for people, such as face recognition; the other is for objects, such as sweeper to avoid obstacles; the third is for focusing, whether it is camera module or projector, it is a kind of focusing. By using the features of real-time sensing and measurement error fixation of TOF technology, the measurement accuracy will not decrease with the increase of the measurement distance. When the screen blurs in the projection play or the virtual focus caused by projection displacement will be monitored and finally calibrated in real time, so as to achieve the effect of real-time autofocus.
The geometric relationships between a trapezoidal correction is more complex, based on the optical properties of the projector, when plane and projector can placed vertically with each other, the projection surface will present trapezoid image, the current in the vertical direction of the trapezoidal automatic correction technology is mature, built-in gravity sensor can, but in horizontal direction of the existing sensor can't perceive level Angle change. Using TOF technology can be faster and more accurate real-time location, the perception of horizontal plane Angle changes. Still when becks F1C, for example, the configuration of dual laser TOF technology, using TOF range around the projection distance measuring module, combined with the Angle of projection light machine information and dual laser ranging module Angle, through the calculation of geometric mathematical relationship between trapezoidal variation, needed to define the parameters of the trapezoidal correction value to correct image. Therefore, by rotating the projection Angle at will, TOF technology can send back the data in real time, and then through the calculation and processing of the built-in chip, finally realize the "positive" screen display of any Angle.
TOF has become a mainstream 3D sensing solution due to its small module size, relatively low cost and excellent real-time sensing capability. Since it can be popular in the mobile phone field, it can also play an increasingly important role in projection.
