What Is a Time of Flight Sensor and How Does ToF Work?
As smartphones become more advanced, they also pack an increasingly high amount of sensors that feed data back to the device to make the user experience better.
Modern smartphones have in-display fingerprint sensors, LiDAR, better and bigger camera sensors than ever, and on some devices, even Time of Flight (ToF) sensors. But out of all the different sensors you’ll see on your phone, the ToF sensor strikes out, mostly because it affects the things we do on our smartphones in a very particular and unnoticed way.
What Is a Time of Flight (ToF) Sensor?
A Time of Flight (ToF) sensor, also called a ToF camera, is a specialized sensor that measures the depth or distance to an object by emitting an infrared beam of light and measuring the time it returns. Hence the name, Time of Flight.
This is very similar to the LiDAR cameras found on the iPhone Pro lineup and even on some smartphone (including iPhone) facial detection systems, where the device creates an infrared map of the owner’s face and uses that as a reference against the person it’s seeing to determine whether to unlock the device or not. That said,ToF sensors and LiDAR do have their differences.
Using reflected light (or sound) to measure distance isn’t a new idea either. Similar devices such as ultrasonic and IR sensors have been around for much longer, providing essentially the same functionality, albeit with a lot less detail. A ToF sensor’s advantages include precise and fast measurements, a longer range, and safety of use.
Compared to other 3D-depth measurement technologies, ToF sensors are relatively cheap to produce and use. They also don’t require much processing power, making them ideal for use cases like smartphones, where knowing the depth of a particular object can help facilitatefeatures like portrait mode, and processing power is at a premium.
ToF sensors are made by various manufacturers, including Sony, which provides Apple with 3D sensors using ToF technology. Other popular ToF sensor manufacturers include TeraRanger One, Lucid, Adafruit, and ASC TigerCub.
How Does a Time of Flight (ToF) Sensor Work?
As mentioned before, ToF sensors use infrared light to measure an object’s distance from the sensor. A tiny infrared laser shoots light, which bounces off of an object and returns to the sensor. The sensor can accurately measure the distance of an object by measuring the time it took for the light to bounce back and return to the camera.
Since we already know the speed of light and the fact that it’s traveling exactly twice the distance between the sensor and the object, it becomes simple to figure out the distance using a basic formula:
(Speed of light x Time of Flight)/2
Some ToF cameras can also use continuous waves to detect phase shifts in the reflected light to determine both depth and distance. Again, depending on the type of sensor you’re using, you might be able to extract a lot of information. This can be used to create 3D maps of the sensor’s surroundings.
Where Are ToF Sensors Used?
As mentioned, ToF sensors were used in many smartphones as a “depth” camera to aid the device’s main camera in producing higher quality portrait mode photos. These photos aim to create a shallow depth of field to replicate a camera lens. Since knowing the depth of different objects in such photos is critical to getting the blurriness of the background right, ToF cameras and sensors can make quite the difference.
In addition, ToF cameras are also used in biometric authentication, where a device with a ToF camera can create a 3D map of a face to use as a reference for unlocking the device. This is essentially howface unlocking technology works, including Apple’s Face ID. It’s also more secure than just comparing two images to determine a match, as there is more data to work with compared to traditionalcomputer visionalgorithms that operate on 2D data.
They’re commonly used in electric cars and other navigation systems thanks to their object detection capabilities and high polling rate, which can be nearly 160Hz on some sensors. This makes them perfect for real-time applications such as object detection, navigation, and even blurring the background on your Zoom calls.
This ability to differentiate between the subject and the background is also often applied to 3D printing. ToF cameras can easily replicate a real-life object in all three dimensions, saving you the hassle of designing it from scratch, especially if it’s a complex structure.
ToF sensors also help in 3D imaging and improving AR experiences in addition to object scanning, gesture navigation, and indoor navigation.
you’re able to find ToF sensors on Microsoft’s Xbox Kinect and othergesture recognition projects, drones, and AR headsets. Overall, their versatility means that their use cases range from anywhere between a smartphone camera suite to an autonomous car’s navigation system.
Do You Need a ToF Camera on Your Phone?
Not really.
Computational photography has come a long way, and most modern smartphones have good enough software to separate the subject from the background completely using software. Additionally, when it comes to smartphone photography, the megapixel count and camera sensor size can make a much bigger difference.
While there was a time when ToF cameras were commonly seen on flagship smartphones, they’re now mostly found on mid-range devices or on the iPhone Pro lineup in the form of LiDAR sensors, a concept that works on the Time of Flight principle.
However, having a ToF camera on your phone can come in handy at times, especially in terms of biometric authentication. It can also provide a distance measuring utility built into your phone and provide more depth data to the computation photography software running on your phone, resulting in even better portrait mode shots.
Know Your Sensors
Smartphones are being packed with more and more sensors to make your experience that much better. A ToF camera is just another one of those sensors on your phone that can’t be used directly but can make a big difference to several other features.
Your smartphone is a seriously high-tech bit of kit.
These are the best free movies I found on Tubi, but there are heaps more for you to search through.
Every squeak is your PC’s way of crying for help.
Some subscriptions are worth the recurring cost, but not these ones.
Make sure you don’t miss these movies and shows before Netflix removes them.
The fix was buried in one tiny toggle.
