Infineon Hybrid ToF System Compensates for the Disadvantages of Standard Indirect ToF and Maximizes Its Advantages

Simultaneous operation of ToF sensor, near light source, and far light source… Simultaneous implementation of robot mapping and obstacle detection functions
Infineon to hold webinar on Indirect ToF system on September 26… Principles, specifications, etc. to be shared

[Editor's Note] Time-of-Flight (ToF) technology, which measures the distance to objects using light, has recently been receiving significant attention in the sensor field due to its diverse applications, including object recognition, gesture control, and environmental sensing and measurement. In particular, there is a clear increase in demand in fields such as smartphones and IoT devices, as well as AR/VR, automobiles, and drones. Infineon's Hybrid ToF system, developed using Indirect ToF, compensates for the disadvantage of shorter measurement distances compared to the conventional Direct method while maintaining the advantage of high resolution. To explore the ToF system further upgraded by such Infineon technology, this publication will host a webinar with Infineon on September 26 under the theme "Introduction to Time-of-Flight Technology Realizing the Digitization of Real Space and Infineon's Indirect ToF System." Ahead of the webinar, we listened to the story of Manager Kang Sang-won, who will be speaking.

▲ Kang Sang-won, Manager, Power & Sensor Systems Business Unit, Infineon Korea

Please explain ToF technology and its applications in typical user sectors.

ToF is a technology that measures the distance to an object by measuring the time it takes for a signal sent from a transmitter to return to a receiver after hitting an object, i.e., the time of flight. The 3D Depth Camera method, which transmits an IR laser and receives it through a camera, is the most common and advanced.

While ToF has primarily been utilized in gesture control and frequently applied to AR/VR technologies for humans, it is now being adopted as the most efficient sensor solution for object recognition and spatial mapping in the rapidly expanding robotics market, driven by recent advancements in AI technology. It serves as the representative sensor responsible for the 'vision' of robots.

In addition to this, it is also widely used for in-vehicle driver and passenger monitoring systems or to enhance the security level of facial recognition technology.

■ What are the differences between Direct ToF and Indirect ToF systems?

ToF technology includes the Direct method, which calculates distance by directly measuring the time difference between a signal emitted from a transmitter, hitting an object, and returning to a receiver, and the I method, which converts the phase difference between the transmitted and received signals into distance.There is an indirect method.

Direct-type 3D Depth cameras have the advantage of being able to measure longer distances.

On the other hand, since multiple SPADs (Single Photon Avalanche Diodes) must be used for each pixel of the Imager to measure the time it takes for the light to return, there is a disadvantage in that the Imager is expensive and the camera resolution is low due to the large pixel size.

An indirect 3D depth camera provides two storage spaces for each pixel of the image to store the received signal, dividing it into when the transmitter is turned on and when it is turned off, and calculates the phase difference with the transmitter using the difference in the amount of charge stored in the two spaces and converts it into distance.

Although it has the disadvantage of a shorter measurement distance compared to the Direct method because the difference in charge stored in the two spaces decreases over long distances, it has the advantage of a lower imager price as it does not require separate optical components like SPADs, and significantly higher camera resolution due to the ability to miniaturize pixels.

■ I am curious about the features and strengths of Infineon's Indirect ToF solution.

Infineon's Hybrid ToF system, developed using Indirect ToF, compensates for the disadvantage of the short measurement distance of conventional Indirect ToF compared to the Direct method while maintaining the advantage of high resolution.

This 3D Depth camera solution is equipped with an Infineon ToF sensor, a flood light source for near range, and a spot light source for far range, and operates them simultaneously, making it highly efficient in terms of both price and performance.

Through these strengths, robot mapping and obstacle detection capabilities are implemented simultaneouslyIt can be manifested.

■ What is the key content of this webinar?

Through this webinar, we will share the basic principles of how ToF technology operates, as well as the differences and advantages and disadvantages of the Direct and Indirect methods, and help you understand the structure of 3D Depth Cameras and the Hybrid ToF System implemented with Infineon's Indirect ToF solution.

In addition, we plan to introduce real-world market application cases of ToF applications, as well as the specifications of Infineon ToF Imagers and related products.

■ A word to the readers of e4ds

ToF is a sensor akin to human 'vision' and is a key device for the digitalization of space for both humans and robots.

Since the entire process, from the operating principles of the sensor to the results produced by the system, is interesting, I hope this opportunity will allow you to become more familiar with ToF technology and learn how to utilize it effectively.