Technical information

Toppan’s hybrid ToF™ Sensor

Target application of new ToF sensor

Our newly developed hybrid ToF™ (hToF™) sensor employs the unique ToF sensing method that combines the features of both indirect and direct ToF.
This sensor specializes in 3D sensing up to medium distances, which was difficult to achieve with the conventional indirect ToF method.
It is suitable for applications that require sensing in wide ranges, such as small robots, drones, and AGVs.

Performance required for the target application

hybrid ToF™ Sensing Method

The Toppan’s unique hToF™ sensing method employs two features the indirect ToF (iToF) method and the direct ToF (dToF) methodNote1.
This method estimates ToF using multiple windows of short intervals (multi-time window technology).
Our new method is superior to the conventional iToF method for outdoor use because it is less susceptible to external light noise.

Basic principle of distance estimation by our ToF sensing method

Note1[Reference] S. Kawahito et al.(2021) “Hybrid Time-of-Flight Image Sensors for Middle-Range Outdoor Applications” IEEE OJSSCS, 2021.

Subframe Operation

The subframe operation is available to change the position of the time window for each frame.
By combining multiple subframes, the measuring range can be extended.
This sensor can flexibly expend the working range by using this technique as well as the time window adjustment of each gate.

Subframe operation

Dynamic Ambient Light Suppression Technology

The Dynamic Ambient Light Suppression (DALS) technology optimized for the hybrid ToF™ sensing method together with the multi-time window technique enables depth sensing with a wide working range even outdoors compared to conventional iToF sensors.
It is demonstrated that even in daylight (under 100k lux ambient light), our newly developed ToF sensor can measure objects (marker boards) located from a short distance of 1m to a medium distance of 20m.

Performance verification evaluation using a prototype sensor

Smart interference cancellation function

Smart interference cancellation function is a feature that automatically cancels the effects of interference caused by the ToF camera light source by dynamically controlling the sensor's internal operation.
By using this function, multiple drones and AGVs equipped with ToF cameras can be run simultaneously without mutual interference in the same working space. Since this function is embedded in the sensor, the user has no need to coordinate between ToF cameras.

High-sensitivity and high-resolution ToF pixels

Our newly developed ToF pixels are much smaller than our conventional products, and offer both high-definition and high-sensitivity performance.
A larger number of pixels will enable more precise area 3D sensing.

Features of newly developed ToF pixel (comparison with conventional products)

Related Information

Conference and Publication

C05-2: A Hybrid Indirect ToF Image Sensor for Long-Range 3D Depth Measurement under High Ambient Light Conditions

2023 IEEE Journal of Solid-State Circuits
A Hybrid ToF Image Sensor for Long-Range 3D Depth Measurement Under High Ambient Light Conditions