What is a DToF (Direct Time-of-Flight) Sensor?
DToF (Direct Time-of-Flight) sensor, or direct time-of-flight sensor, is a high-precision distance measurement technology based on the principle of light pulse flight time measurement.
It calculates the distance between the sensor and the target object by measuring the flight time of the light pulse from emission to reflection back to the receiver by the object.
Analog distance sensors – Aluminum sweeper sensors – Metal material distance measuring ultrasonic sensors
With its high precision, fast response, low power consumption and accuracy in multi-object detection, DToF sensors have shown wide application potential in smart devices, industrial automation, unmanned driving and other fields.
Working principle
The working principle of DToF sensors is based on the constancy of the speed of light and precise timing technology. When a laser transmitter emits a light pulse, an electronic clock is activated.
Robot reversing radar sensor – Robot reversing radar lateral mouse repellent sensor – Analog type sonic aluminum shell 1040 ultrasonic sensor
This light pulse is guided to the desired direction, irradiated onto the target object, and reflected back from the surface of the object. A portion of the reflected light is received by the photodetector, generating an electrical signal that stops the clock. By measuring the flight time Δt of the light pulse, the distance d between the sensor and the target object can be calculated.
The calculation formula is d=cΔt/2, where c is the speed of light in the medium (usually the speed of light in a vacuum, about 3×10^8 m/s).
The core of DToF technology is its ability to directly measure the flight time of a single photon, thanks to the application of advanced technologies such as single-photon avalanche diodes (SPADs) and time-correlated single-photon counting (TCSPC).
SPADs are highly sensitive and can detect extremely weak light signals, while TCSPC can accurately measure the arrival time of photons, thereby achieving accurate distance measurement.
Calculation formula
The distance calculation formula for DToF sensors is d=cΔt/2, where:
- d is the distance between the sensor and the target object;
- c is the speed of light in the medium, usually the speed of light in a vacuum, about 3×10^8 m/s;
- Δt is the flight time of the light pulse from emission to reception.
This formula is the basis for DToF sensor distance measurement. Through precise timing technology and the constancy of the speed of light, accurate distance measurement can be achieved.
Release time and invention country
Although DToF sensors were commercialized late as independent products, their technical principles have been widely used in fields such as optical measurement and laser ranging.
With the rapid development of science and technology, especially the popularization of artificial intelligence, the Internet of Things and smart devices, DToF sensors have gradually achieved commercial breakthroughs and a wide range of application scenarios.
As for the specific invention time and country, it is difficult to determine an exact invention time and country because it is a technology that is gradually developing and improving.
But it is certain that the development of DToF sensor technology is inseparable from the efforts and contributions of many scientific research institutions and companies around the world.
Product example
STMicroelectronics’ VL53L9 is a representative DToF sensor product. VL53L9 is STMicroelectronics’ latest DToF sensor and its first true 3D DToF lidar product.
It has up to 2,300 detection areas and extremely high resolution, supports a maximum frequency of 60Hz, and can accurately detect within a range of 5cm to 10m.
Whether it is still images or 60 frames per second video shooting, VL53L9 can provide laser autofocus, defocus and movie mode functions, greatly improving the performance and user experience of smart devices.
In addition, the fully integrated precise direct time-of-flight ranging DToF sensor MT3801 launched by Maxic is also a product worth paying attention to.
It is based on single-photon time-of-flight for precise ranging, and the ranging range supports up to 5m. It also integrates SPAD, algorithm processing module, Cortex M0 core and 940nm VCSEL and optical filter, which can be widely used in mobile phones/Pads, sweepers, hair dryers, faucets, smart toilets, projectors, drones and other fields.
DToF sensor application scenarios
DToF sensors have shown wide application potential in many fields with their high precision, fast response and low power consumption. Here are some typical application scenarios:
1. Smartphone:
In the field of smartphones, DToF sensors have become an indispensable configuration. It can significantly improve the autofocus performance of mobile phone cameras and support shooting from macro cameras to telephoto cameras.
Whether it is still images or 60 frames per second video shooting, DToF sensors can provide laser autofocus, defocus and movie mode functions, allowing users to easily capture every wonderful moment.
In addition, DToF sensors can also be used to enhance the experience of AR (augmented reality) applications, achieving more accurate virtual object placement and interaction.
2. VR system:
In VR systems, DToF sensors can use accurate depth maps and 2D images to improve the accuracy of 3D reconstruction and enhance immersive gaming and virtual reality experiences.
Whether it is a virtual tour or a 3D avatar, DToF sensors can make users feel a more realistic and immersive virtual world.
3. Industrial automation:
In the field of industrial automation, the small object edge detection capability of DToF sensors makes it suitable for applications such as machine automatic navigation SLAM (simultaneous localization and mapping).
Through accurate ranging and positioning information, DToF sensors can help robots achieve autonomous navigation and obstacle avoidance functions, improving production efficiency and safety.
4. Unmanned driving:
In the field of unmanned driving, DToF sensors can be used to achieve precise positioning and navigation of vehicles.
By integrating with other sensors such as radar and cameras, DToF sensors can provide richer environmental perception information to help vehicles achieve autonomous driving and obstacle avoidance.
5. Smart home:
In the field of smart home, DToF sensors can be used to achieve automatic control and energy saving functions of smart devices. For example, by detecting the user’s approach distance to automatically turn on and off lights, air conditioners and other equipment; or by detecting the position of objects to automatically adjust the operating status of home appliances, etc.
Solving industry problems
The application of DToF sensors has brought significant technological progress and solutions to multiple industries. Here are some examples of DToF sensors solving industry problems:
1. Improving measurement accuracy:
DToF sensors calculate distance by directly measuring the flight time of light pulses, and have the characteristics of high accuracy and fast response. This makes it excel in scenarios that require high-precision measurements, such as machine navigation and positioning in industrial automation, vehicle navigation and obstacle avoidance in unmanned driving, etc.
2. Enhanced environmental adaptability:
DToF sensors have strong anti-interference ability and low power consumption, and can work stably in complex environments. This allows it to maintain excellent performance in challenging scenarios such as outdoor and strong light, such as outdoor device control in smart homes, vehicle navigation under sunlight interference in unmanned driving, etc.
3. Promote technological innovation:
The application of DToF sensors has promoted technological innovation and development in many fields. For example, in the field of smartphones, the introduction of DToF sensors has enabled mobile phone cameras to achieve more accurate autofocus and AR application experience; in the field of industrial automation, the application of DToF sensors has promoted the development of robot autonomous navigation and intelligent control technology, etc.
Distance Detection Sensor – Robotic Reversing Radar Sensor – Ultrasonic Sensor
Application fields
DToF sensors have a wide range of applications, covering smart devices, industrial automation, unmanned driving, smart homes and other fields. The following are some specific application fields:
1. Smart devices:
DToF sensors are widely used in smart devices, such as smartphones, tablets, smart wearable devices, etc. By providing high-precision ranging and positioning information, DToF sensors can help these devices achieve more accurate autofocus, gesture recognition, AR applications and other functions.
2. Industrial Automation:
In the field of industrial automation, DToF sensors can be used to achieve precise navigation and positioning functions of machines. By combining with robot control systems, DToF sensors can help robots achieve autonomous navigation, obstacle avoidance, material handling and other functions, improving production efficiency and safety.
3. Unmanned Driving:
In the field of unmanned driving, DToF sensors can be used to achieve precise navigation and obstacle avoidance functions of vehicles. By integrating with other sensors such as radar and cameras, DToF sensors can provide richer environmental perception information to help vehicles achieve autonomous driving and intelligent obstacle avoidance functions.
4. Smart Home:
In the field of smart home, DToF sensors can be used to achieve automatic control and energy-saving functions of smart devices. For example, by detecting the user’s approach distance to automatically turn on and off lights, air conditioners and other equipment; or by detecting the position of objects to automatically adjust the operating status of home appliances, etc. This can not only improve the convenience of users’ lives, but also achieve energy conservation and environmental protection.
Direct Time of Flight (dToF) Application Cases
MT3801 sensor specifications – MT3801 sensor datasheet manual
Influence in the Internet of Things
The influence of DToF sensors in the field of the Internet of Things (IoT) is becoming increasingly significant. With the rapid development and popularization of IoT technology, more and more smart devices are connected to the network, forming a huge IoT ecosystem. As one of the representatives of high-precision ranging technology, DToF sensors play an important role in the Internet of Things.
1. Improving perception capabilities:
The high-precision ranging capability of DToF sensors enables IoT devices to more accurately perceive changes in the surrounding environment. For example, in smart home systems, DToF sensors can detect the user’s approach distance and movement trajectory, thereby achieving more intelligent device control and energy-saving functions. In the field of industrial automation, DToF sensors can help robots achieve more accurate navigation and positioning functions and improve production efficiency.
2. Promoting data fusion:
The fusion of DToF sensors with other sensors (such as radars, cameras, etc.) can provide richer environmental perception information.
The fusion and analysis of these data can help IoT systems achieve more intelligent decision-making and control functions. For example, in unmanned driving systems, the fusion of DToF sensors with radar, cameras and other sensors can provide more comprehensive information about the vehicle’s surrounding environment, thereby improving the vehicle’s autonomous navigation and obstacle avoidance capabilities.
3. Promoting technological innovation:
The application of DToF sensors has promoted technological innovation and development in the field of the Internet of Things. For example, in the field of smartphones, the introduction of DToF sensors has enabled mobile phone cameras to achieve more accurate autofocus and AR application experience; in the field of industrial automation, the application of DToF sensors has promoted the development of robot autonomous navigation and intelligent control technology, etc.
These technological innovations not only improve the performance and user experience of IoT devices, but also lay a solid foundation for the future development of the field of the Internet of Things.
Summary
As a high-precision ranging technology, DToF sensors have shown wide application potential and important technical value in many fields such as smart devices, industrial automation, unmanned driving, and smart homes.
Its working principle is based on the constancy of the speed of light and precise timing technology, and the distance is calculated by measuring the flight time of light pulses.
The DToF sensor has the characteristics of high precision, fast response, low power consumption, and accuracy in multi-object detection, which makes it perform well in multiple scenarios.
With the rapid development of science and technology and the popularization of IoT technology, the application prospects of DToF sensors will be broader. In the future, we can expect DToF sensors to play an important role in more fields and bring more convenience and innovation to people’s lives and work.
At the same time, with the continuous advancement of technology and the reduction of costs, DToF sensors will gradually become popular in the hands of more consumers and become an important force to promote social progress and development.
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FAQs
Here are some common questions and answers about DToF (Direct Time-of-Flight) sensors:
A DToF sensor is a distance measurement sensor based on the time-of-flight (ToF) principle. It calculates the distance between the sensor and the target object by measuring the flight time of a light pulse from the emission to the reflection of the object back to the receiver.
The working principle of a DToF sensor is to emit a short pulse of light and then measure the time required for the emitted light to return to detect the distance to the object. Its transmitter usually uses a short pulse laser of nanosecond or even picosecond level, and the receiver selects a sensor suitable for event recording, such as SPAD (single photon avalanche diode) or APD (avalanche photodiode). By measuring the flight time Δt, the distance to the reflecting object is calculated according to the formula d=cΔt/2 (where c refers to the speed of light in the medium).
dToF means direct time of flight, which is a distance measurement principle that calculates the distance by measuring the time it takes for a light signal to propagate in space. This technology has the advantages of high precision and strong anti-interference ability, and has broad application prospects in robot navigation, autonomous driving, 3D imaging and other fields.
DToF sensors have the advantages of accurate measurement, fast response, low power consumption and accurate simultaneous detection of multiple objects. In addition, it is less sensitive to ambient light interference and can work in scenes with different light intensities.
The main difference between DToF sensor and iToF (indirect ToF) sensor lies in the measurement method. iToF indirectly calculates the flight time by measuring the phase difference between the transmitted signal and the reflected signal, while DToF directly measures the flight time of the light pulse. Therefore, DToF performs better in ranging accuracy, response speed and low power consumption.
DToF sensors are widely used in smart devices, home appliances, industrial automation, self-driving cars, robots, drones and consumer electronics. Especially in the field of consumer electronics, with the rise of new applications such as AR/VR, the demand for DToF sensors is also rising rapidly.
The core technologies of DToF sensor include SPAD (single photon avalanche diode) and time-correlated single photon counting (TCSPC). SPAD is the core technology for realizing DToF. It can generate response current in ps level time, so as to realize the detection of weak light signal. TCSPC is a method to measure the time information of photons. By counting the number of photons in each time period after a large number of repeated measurements, the frequency distribution histogram of photons changing with time is obtained, and then the intensity change of light signal is obtained by fitting.
When choosing a DToF sensor, factors such as ranging range, ranging accuracy, resolution, power consumption and cost need to be considered. In addition, it is necessary to select sensors with specific functions according to specific application scenarios and requirements, such as anti-ambient light interference ability, multi-object synchronous detection ability, etc.
When using DToF sensor, it is necessary to avoid using it in an environment with strong light source or strong reflective objects, so as not to affect the normal emission and reception of laser. At the same time, it is necessary to ensure that the connection between the sensor and the motherboard is firm and reliable to avoid loosening or falling off to cause signal transmission problems. In addition, during use, attention should be paid to the heat dissipation and protection of the sensor to ensure its long-term stable operation.
A dToF robot vacuum cleaner refers to a robot vacuum cleaner that uses direct time of flight (dToF) technology. This technology calculates the distance by measuring the time difference from the emission to the reception of the light signal, thereby achieving accurate navigation and obstacle avoidance functions, and improving the cleaning efficiency and effect of the vacuum cleaner.
A dToF vacuum cleaner also refers to a vacuum cleaner that uses dToF technology. This technology enables the vacuum cleaner to perceive the surrounding environment more accurately, avoid colliding with furniture and obstacles, and improve the accuracy and efficiency of vacuuming.
A dToF camera is a depth camera that uses direct time of flight technology, also known as a 3D camera. It adds distance or depth information to each pixel of the image by emitting a laser beam and measuring the flight time of the reflected light signal. This technology can accurately measure the distance between objects in a complete scene in real time, and is widely used in robotics, AR/VR, autonomous driving and other fields.
dToF technology is a technology that calculates distance by directly measuring the time difference from the emission to the reception of a single photon. It eliminates the complex phase solution process, thereby achieving a qualitative leap in measurement accuracy and anti-interference ability. dToF technology has the advantages of high precision, long-distance ranging, and strong anti-interference ability, and is widely used in consumer electronics, automotive, industrial automation and other fields.
dToF and LiDAR are both ranging technologies, but their implementation methods and application scenarios are different. LiDAR (Light Detection and Ranging) is a technology that calculates distance by measuring the time from the emission to the reception of a light pulse, while dToF (Direct Time of Flight) is an implementation method of LiDAR technology.
dToF calculates distance by directly measuring the time difference from the emission to the reception of a single photon, and has the advantages of high precision and long-distance ranging. Therefore, dToF technology is often used in LiDAR systems to achieve more accurate ranging and imaging.
LiDAR technology is the abbreviation of Light Detection And Ranging. It is a system that integrates three technologies: laser, global positioning system (GPS) and inertial navigation system (INS) to obtain point cloud data and generate accurate digital three-dimensional models. LiDAR technology calculates the distance between the object and the detector by emitting laser pulses and measuring the time difference of reflection, thereby achieving the acquisition and modeling of three-dimensional real scenes.
ToF sensors are mainly used to accurately measure the distance between objects, providing centimeter-level measurement accuracy, and are widely used in three-dimensional perception, object recognition and tracking, obstacle detection and avoidance, SLAM (simultaneous localization and mapping), augmented reality and virtual reality.
The role of ultrasonic distance sensors:
Ultrasonic distance sensors are devices used to emit and receive ultrasonic waves. They can use the characteristics of ultrasonic waves for ranging. Ultrasonic waves have great penetrating power for liquids and solids. When they encounter impurities or interfaces, they will produce significant reflections to form echoes. Therefore, ultrasonic sensors can accurately measure the distance between objects. Ultrasonic distance sensors can be widely used in related fields such as level (liquid level) monitoring, robot anti-collision, various ultrasonic proximity switches, and anti-theft alarms.
The role of ToF sensors:
ToF sensors, or Time of Flight sensors, can accurately calculate the distance to the target object by measuring the time it takes for light to be emitted from the target object and then return, combined with the speed of light, and provide centimeter-level measurement accuracy. ToF sensors have a variety of application scenarios, including three-dimensional perception, object recognition and tracking, obstacle detection and avoidance, SLAM (simultaneous localization and mapping), augmented reality and virtual reality, gesture recognition and human-computer interaction, facial recognition and biometrics, etc.
A photoresistor sensor is a sensitive device that responds to or converts external light signals or light radiation. Photoresistors are one of the most common types, and are often made of semiconductor materials such as cadmium sulfide or cadmium selenide. These materials have the property that their resistance decreases rapidly when exposed to light of a specific wavelength, so the characteristic of photoresistors is that the stronger the light, the lower the resistance. Photoresistors are often represented by the letters “R” or “RL” or “RG” in circuits.
The LiDAR sensor in a vacuum cleaner is an active ranging sensor that calculates the distance to the target object by emitting a laser beam and measuring its echo time. The LiDAR sensor can continuously rotate and scan to draw a three-dimensional image of the surrounding environment, allowing the vacuum cleaner to “see” the surrounding environment and continuously update and optimize the cleaning path.
