Road surveillance cameras require LED fill light angles

In order for road surveillance cameras to clearly capture license plates at night, on the one hand, the camera's strong light suppression index must be good, which can effectively suppress the oncoming strong light so that the license plate can be captured more clearly and the picture is real and complete; on the other hand, it is required to provide fill light for the object.

　　The quality of backlight compensation technology is directly related to whether the license plate can be clearly seen and whether the back-end video detection and analysis system can give correct judgment results. The clarity of the photo depends on the choice of a surveillance camera with backlight compensation, and an LED fill light needs to be added. In addition to the light emitted by the vehicle lamps themselves (which is harmful to the camera), outdoor vehicles also have the light of the environment itself. The amount of ambient light diffusely reflected from the vehicle to the camera is very small, which requires the addition of LED fill lights to increase the brightness of the illuminated object to meet the camera's requirements for light. The mainstream intelligent transportation integrators in the market currently have many classifications of illumination requirements for LED fill lights, and there is no unified standard. They all require that objects can be clearly illuminated at about 20 meters.

　　It can be roughly divided into two categories: one is the distance of 17 meters to 20 meters, and the required illumination is 100Lux; the other is the distance of 20 meters to 23 meters, and the illumination requirement is 200Lux.

　　In the case of a single lane, that is, when the lamp is at a height of 6 meters, a distance of 20 meters, and the lane width is 3.5 meters, the actual required light angle is 9.58 degrees.

　　In the case of two lanes, that is, when the height is 6 meters, the distance is 20 meters, and the width of the two lanes is 7 meters, the actual required light angle is 19 degrees.

　　These two solutions can be designed in a combination of a reflective bowl and a lens, taking advantage of the small-angle focusing of the reflective bowl and the light distribution of the lens to achieve maximum light efficiency, while also achieving the best effect of uniform lighting within the required range.