Electronic cameras often use infrared (IR) technology, specifically Time-of-Flight (ToF) or Active IR methods, to measure the distance to the subject. Here’s how each method works:
1.Time-of-Flight (ToF):
（1）Time-of-Flight cameras emit short bursts of infrared light pulses towards the subject. These pulses bounce off the subject and return to the camera’s sensor. By measuring the time it takes for the light to travel to the subject and back, the camera calculates the distance to the subject.
（2）ToF cameras typically use semiconductor sensors, such as CMOS or CCD sensors, to detect the reflected infrared light. These sensors have fast response times and can accurately measure the time delay between the emitted and received light pulses.
（3）By scanning the entire field of view with multiple light pulses, ToF cameras generate depth maps or point clouds, representing the distance to objects in the scene. This information can be used for various applications, including autofocus, gesture recognition, and 3D imaging.
2.Active Infrared (IR) Sensing:
（1）Active IR sensors emit infrared light towards the subject and measure the intensity of the reflected light. The distance to the subject is inferred from the strength of the reflected IR signal.
（2）Active IR sensors typically use infrared LEDs to illuminate the scene. These LEDs emit light at specific wavelengths that are invisible to the human eye but detectable by the camera’s sensor.
（3）The intensity of the reflected IR light depends on the distance to the subject and the reflective properties of the surface. By analyzing the intensity of the reflected light, the camera can estimate the distance to the subject.
（4）Active IR sensing is commonly used in proximity sensors, object detection systems, and depth-sensing cameras. It provides accurate distance measurements over short to medium ranges and is suitable for various applications, including robotics, automotive, and consumer electronics.
Both ToF and active IR sensing methods enable electronic cameras to accurately measure distances to subjects or objects in the scene. These technologies have diverse applications in fields such as photography, computer vision, augmented reality, and autonomous systems, enhancing the capabilities of modern imaging devices.
