ToF Image Sensors
The ability to measure objects at a distance to determine how far away they are and/or their overall dimensions is becoming more popular in Imaging. With this, there are several different techniques and technologies, each with their own advantages and disadvantages. Picking the right one can be daunting without someone in your corner to help decipher your needs and direct you to the best product to meet them.
A popular technology that is gaining recognition is Time of Flight (ToF) for its simplicity and ease of use. These products are based on measuring the time it takes light to travel to and from a reflective surface. It works by having a camera send out a light pulse or stream of pulses and measuring the time delay for it to be detected back at its sensor’s pixels. With this time measured, an accurate distance can then calculated and a depth map created.
There are two distinct approaches used in ToF systems, each with their specific advantages within a given application. Direct ToF (dToF) uses a short light pulse, about a few nanoseconds in length, the delay between the emission and the reflection from the target is measured and the distance to the target can then be determined.
For Indirect ToF (iToF), the principle is similar to dToF with the exception of pulses of light are sent as a stream, where the emitted light is modulated. The receiving sensor repeatedly measures reflected light identifying the phase difference between the outgoing and reflected signal. This phase angle can then be used to determine the distance of the target through a simple calculation.
In addition to imaging in X and Y directions, 3D image sensors also acquire the Z-direction (e.g. depth) information, enabling 3D sensing. ToF image sensors detect distance information of each pixel, creating highly accurate depth map.
3D sensing opens up the possibility of discerning things that are difficult with conventional 2D images, as in inspection based on volume or shape, or discerning overlapped objects.
Sony has introduced a line of iToF products such as IMX556 and the new IMX570 sensor that are especially effective in high-speed, high-resolution 3D imaging of objects at short and long distances.
Key Features of Sony’s New IMX570 Sensor
The new IMX570 is a 1/4.5-type VGA sensor with 5 µm pixels that reaches a frame rate up to 56 fps.
Key Features of Sony’s IMX556 Sensor
The IMX556 is a type 1/2-type VGA sensor with 10 µm pixels that reaches a frame rate up to 60 fps.
Ideal for optimizing material handling lines by measuring positions, sizes and loading rate of pallets or cargos, and for autonomous mobile systems such as AGVs and last-mile robots.
Detection of intrusion into hazardous area, operation monitoring and object location detection for robot picking.
Commercial & Public Facilities
Easy and accurate measurement of crowd levels at stores, airports, theme parks and other public locations as well as sophisticated access control.
Farming & Agriculture
Quality control and productivity improvements, e. g. automated milking, body condition scoring, feed amount detection along with other shape related applications like automatic fruit picking.
Civil Engineering & Construction
Detection of environmental features or objects and support for driver assistance, vehicle automation, site visualization/documentation.
Sony’s IMX570 Features State-of-the-Art iToF Technology
Sony has released a back-illuminated, time-of-flight 3D image sensor for industrial machineries. The new IMX 570 is a type 1/4.5 VGA sensor with 5 µm pixels.
Applying Sony’s sensing and ranging technologies, the compact and high-resolution sensor acquires depth data which can cover both short and long distances.
Key Features of Sony’s New IMX570 Sensor: