What Is a 3D Sensor?
A 3D sensor is a device that captures three-dimensional shapes. Unlike traditional cameras that capture flat two-dimensional information, a 3D sensor also obtains height information, adding a third dimension to the captured data.
3D sensors act as a substitute for human senses like vision and touch, enabling the perception and analysis of three-dimensional spaces and objects. This technology is broadly referred to as 3D sensing.
Types of 3D Sensors
3D sensors vary based on their measurement techniques. The three main types of sensing methods used to acquire 3D shapes are time-delay, triangulation, and focus.
Time-Delay Method
This method calculates distance based on the time taken for light to reflect to the sensor. It’s capable of measuring distances up to 100 meters or more but with limited accuracy. Common applications include its use in LiDAR systems like TOF sensors for mapping and in automated guided vehicles (AGVs) for object and person detection.
Triangulation Method
Triangulation involves using laser lines and cameras to measure object height from the displacement of the laser line. Stereo Vision, another triangulation method, uses multiple cameras to calculate height differences based on parallax. Stripe and pattern projection methods also fall under this category, offering high accuracy in static conditions.
Focus Method
Focus methods involve white light interference and confocal optics. White light interference uses light interference from multiple wavelengths for precise measurements, while confocal optics utilize a pinhole to detect light at the focal point. Focusing methods, in contrast, alter the camera’s distance to find the best focus position, capturing multiple images for 3D reconstruction.
Uses of 3D Sensors
3D sensors have diverse applications, from automotive to construction machinery. In vehicles, they are essential for real-time recognition and navigation. In construction, they help in unmanned operations by detecting workers and measuring dimensions. The technology also aids in tracking material transport and inventory management.
Principle of 3D Sensors
3D sensing technologies can be classified into passive and active methods. Passive methods use existing light to capture images, while active methods project electromagnetic waves onto objects and measure reflections. Each method has its specific applications and limitations, necessitating careful selection based on the intended use of the 3D sensor.