3D Time-of-Flight cameras – an introduction
A Time-of-Flight camera (ToF camera) uses laser or infrared light to calculate distance between camera and subject by measuring the time taken by the light signal to make the round trip. The camera illuminates the scene with a varying light source and registers the reflected light, then translates that into a distance measurement. The simplest version of a Time-of-Flight camera uses light pulses or a single light pulse. The illumination is switched on for a very short time, the resulting pulse lights the scene and is reflected by objects in its Field of View.
Time-of-Flight vs Stereovision
There are a number of advantages to using ToF technology as opposed to other available technologies.
Stereovision uses two cameras separated by distance, creating a similar set up to the human eye. Problems with this system arise from a disparity created by differing data registered by each camera. Corrections are required to data involving the use of complex algorithms to calculate and allow for variations, with accuracy only achieved once both cameras register corresponding information. Accuracy with Stereo vision is also dependent on there being enough variation in color in the images for adjustments to be effective which can be problematic if the subject contains uniform colour. With ToF technology accuracy is not impacted by differences in color or texture. Both systems are sensitive to distance, but ToF technology is able to overcome this issue using an increase of light intensity.
Time-of-Flight vs Structured light
Structured light functions by projecting patterns onto the subject and interpreting observed distortions to the pattern. This often requires a sequence of interpreted projections to produce one frame, so provides a much lower frame rate than ToF technology. A lower frame rate is problematic when the technology is being used to monitor moving subjects, as it will cause blurring. Structured light is able to achieve high spatial (X-Y) resolution but is sensitive to light conditions and physical alignment. ToF technology tends to be more compact. Current ToF technology has lower resolution than today’s structured-light, but is rapidly improving.
Terabee Time-of-Flight solutions
Terabee compact 3D Time-of-Flight (ToF) depth cameras and sensor modules are lightweight, cost-effective and can be used for a number of applications from measuring volume, to capturing movement and recognizing gestures. Terabee products feature factory calibrated depth data, quick and easy setup, and flexible operating modes.
By using infrared Time-of-Flight technology to sense depth, cameras and sensor modules collect non-intrusive depth image data – personal identity can never be captured. Since our devices do not require ambient illumination for optimal performance, they are suitable for use in low light or even complete darkness.
Terabee 3Dcam 80x60
This compact, robust and affordable 3D Time-of-Flight camera will enable you to build depth sensing applications for use in smart buildings, automation and robotics. With applications in people counting, hand gesture recognition, stock level monitoring, object recognition and room occupancy monitoring, this is an extremely powerful system in a small package.
Key features include Time-of-Flight technology, 80 x 60 pixels depth image, a large detection area of 74° x 57° and privacy protected, non-intrusive data collection. The 3D Time-of-Flight camera benefits from a robust aluminum casing while still offering a compact (83 grams) and discrete design. It is easy to set up with streaming depth data via the USB interface on Windows or Linux OS. Terabee 3Dcam comes with an OpenNI-based SDK, C/C++ samples, Python samples, and ROS package.
TeraRanger Evo 64px
This lightweight Time-of-Flight sensor weighs in at only 12 grams, and has been developed for use in monitoring and tracking motion, sensing depth, people counting and stock monitoring. Designed for indoor use, Evo 64px outputs a matrix of 8×8 high-speed distance readings over a 15 degree Field of View, with a maximum range of up to 5 meters. A free graphical user interface is available for quick tests on your PC, and drivers for ROS are written adding to the plug and play convenience.
TeraRanger Evo sensors consist of an opto-electronic sensing device (black module) and a choice of backboard (yellow model), which simply plugs-in to provide the sensor with its communication link and power management capabilities without the need for adapters or complex wiring. Simply choose the backboard that best suits your application and communication protocol. Both USB and I2C / UART backboards are available. For first time users, we recommend the USB backboard as it allows quick tests on PC with our graphical user interface.
Get your project started today!
Contact us to find out how we can help you develop your own 3D Time-of-Flight based application. Our team have experience and in-depth knowledge of a multitude of technologies and their application in a wide range of sectors. We bring a wealth of creative thinking and technical innovation and have the skills to bring your requirements to life!