1. Focal length
The focal length of the camera in the large truck rear view system is a key optical lens parameter. For the rear camera, a shorter focal length lens is usually used. A shorter focal length (e.g. 3 - 6mm) can provide a wider field of view, which is essential for covering a larger area behind the truck. Because large trucks are long and wide, they need to observe a larger area of the road behind them during reversing or driving, including the area near the rear of the vehicle on both sides of the vehicle and the traffic conditions within a certain distance behind them. For the cameras installed on both sides of the vehicle, if you want to observe the side of the vehicle and the situation at a certain distance behind the vehicle, you may use a medium focal length lens of about 6 - 12mm, so that you can see the situation in the closer area on the side and be able to detect moving objects at a certain distance behind.
2. Aperture size
The aperture size affects the amount of light entering the camera. In the large truck rear view system, the choice of aperture is important because the truck may operate under various lighting conditions, including at night, in tunnels, or under strong light. A larger aperture (such as f/1.8 - f/2.4) allows more light to enter the lens under low-light conditions, ensuring that relatively clear images can be captured at night or in dim tunnels. However, a large aperture may also bring some problems, such as a shallow depth of field, which may cause some areas of the image to be clear and some areas to be blurred. However, in the rear-view system, this effect can be alleviated to a certain extent through reasonable focus and image algorithm processing.
3. Field of view
The field of view directly determines the range that the camera can cover. As mentioned earlier, the field of view of the rear camera is required to be wide, generally reaching about 120° - 180°. Such a wide field of view can minimize the blind spot behind the truck, allowing the driver to see the situation directly behind the rear of the car and in a larger range on both sides. The field of view of the cameras on both sides of the car body may be relatively narrow, but it must be at least 90° - 120° to ensure that the road conditions behind the side of the truck can be observed, especially when turning or changing lanes, so that vehicles or obstacles behind the side can be discovered in time.
4. Optical distortion control
In the large truck rear view system, the optical distortion control of the camera lens is also critical. Due to the imaging principle of the lens, barrel or pincushion distortion may occur. In order to provide accurate image information to the driver, the lens needs to adopt a special optical design or be corrected in the post-image algorithm to minimize distortion. Low-distortion lenses can ensure that the shape and distance relationship of objects in the image can be accurately judged by the driver, thereby improving driving safety. For example, when reversing, accurate distance judgment can avoid collision with objects behind.
