Touchless interface is a human-machine interface technology that allows commanding the computer without physically touching a keyboard, mouse, or screen. Touchscreens are everywhere nowadays on laptops, kiosks, and smartphones. But the increasing hygiene concerns due to the COVID-19 pandemic could open a new era that touchless interface technologies have been waiting for. The three latest trends in touchless interface technologies are voice control, gesture control, and eye tracking. Voice control technology is working very well in certain circumstances, but it is not a good option in public spaces, where it can be noisy or you may not want to speak aloud. A touchless interface based on gesture control can be implemented using a distance image sensor, which can collect 2D imaging and depth information accurately in indoor and outdoor settings.
Figure 1. Touchless interface based on gesture control.
A 3D ToF camera typically consists of a pulsed IR light source, a distance image sensor, and the necessary optics and driver electronics (Fig. 2).
Figure 2. Basic components of a 3D ToF camera.
There are two different types of ToF cameras based on how the depth information of the object is calculated: direct ToF and indirect ToF.
The direct ToF measures the time delay Δ between when the light is emitted and when the reflected light is received by the sensor. The distance between the sensor and the object can be estimated as depth = cΔ/2, where c is the speed of light.
With indirect ToF, a higher distance accuracy can be achieved with easier electronic designs. Hamamatsu’s indirect ToF distance image sensor implements the dual-capacitor pixel structure (Fig. 3). The pulsed light reflects off an object, and strikes the pixel where the photo-generated charge will be recorded in capacitor Cfd1 or Cfd2 shown in Fig. 3. The capacitors are alternately connected to the pixel at the same frequency as the pulsed light source. The distance between the image sensor and the object can be calculated by the ratio of Q1 and Q2.
Figure 3. Operating principle of indirect ToF distance image sensors.
Lu Cheng is an applications engineer, specializing in all of our image sensors and driver circuits. Before joining Hamamatsu, she worked as an analog and mixed-signal ASIC designer. With more than 10 years’ experience in ASIC and circuit board design, she can support you to find the optimized product/solution not only from a user’s perspective but also from a designer’s. Traditional Chinese dancing is one of the things that make her learn about the beauty of the world from a different perspective.
It looks like you're in the . If this is not your location, please select the correct region and country below.
You're headed to Hamamatsu Photonics website for US (English). If you want to view an other country's site, the optimized information will be provided by selecting options below.
For modern websites to work according to visitor’s expectations, they need to collect certain basic information about visitors. To do this, a site will create small text files which are placed on visitor’s devices (computer or mobile) - these files are known as cookies when you access a website. Cookies are used in order to make websites function and work efficiently. Cookies are uniquely assigned to each visitor and can only be read by a web server in the domain that issued the cookie to the visitor. Cookies cannot be used to run programs or deliver viruses to a visitor’s device.
Cookies do various jobs which make the visitor’s experience of the internet much smoother and more interactive. For instance, cookies are used to remember the visitor’s preferences on sites they visit often, to remember language preference and to help navigate between pages more efficiently. Much, though not all, of the data collected is anonymous, though some of it is designed to detect browsing patterns and approximate geographical location to improve the visitor experience.
Certain type of cookies may require the data subject’s consent before storing them on the computer.
This website uses two types of cookies:
There are two ways to manage cookie preferences.
If you wish to restrict or block web browser cookies which are set on your device then you can do this through your browser settings; the Help function within your browser should tell you how. Alternatively, you may wish to visit www.aboutcookies.org, which contains comprehensive information on how to do this on a wide variety of desktop browsers.
Occasionally, we may use internet tags (also known as action tags, single-pixel GIFs, clear GIFs, invisible GIFs and 1-by-1 GIFs) at this site and may deploy these tags/cookies through a third-party advertising partner or a web analytical service partner which may be located and store the respective information (including your IP-address) in a foreign country. These tags/cookies are placed on both online advertisements that bring users to this site and on different pages of this site. We use this technology to measure the visitors' responses to our sites and the effectiveness of our advertising campaigns (including how many times a page is opened and which information is consulted) as well as to evaluate your use of this website. The third-party partner or the web analytical service partner may be able to collect data about visitors to our and other sites because of these internet tags/cookies, may compose reports regarding the website’s activity for us and may provide further services which are related to the use of the website and the internet. They may provide such information to other parties if there is a legal requirement that they do so, or if they hire the other parties to process information on their behalf.
If you would like more information about web tags and cookies associated with on-line advertising or to opt-out of third-party collection of this information, please visit the Network Advertising Initiative website http://www.networkadvertising.org.
We use third-party cookies (such as Google Analytics) to track visitors on our website, to get reports about how visitors use the website and to inform, optimize and serve ads based on someone's past visits to our website.
You may opt-out of Google Analytics cookies by the websites provided by Google:
We inform you that in such case you will not be able to wholly use all functions of our website.