Quality Inspection for Fleet Maintenance Definition - in car video camera systems Big screw camera – Dragon Bridge

Bus monitoring analog camera selection and installation guide

(V1.0) 

Attention: The cameras described in this guide refer to the analog camera with built-in pickup.

First, the camera selection

1) clarity

For color surveillance cameras, 420 TVL (TV line) are medium resolution surveillance cameras, and 480 TVL and above are high resolution surveillance cameras. The higher the clarity, the higher the price. For better image quality, we recommend using a camera of 480 TVL and above.

2) Focal length

The focal length is the distance between the lens and the photosensitive element. By changing the focal length of the lens, you can change the magnification of the lens and change the size of the captured image. Because car cameras usually use fixed-focus cameras, customers need to choose the right focal length camera according to their needs. The larger the focal length of the lens, the larger the magnification, the closer the zoom can be, the smaller the range of the picture, the more detailed the details of the distant view; the smaller the focal length of the lens, the smaller the magnification, the wider the range of the picture, the more visible Big scene. Commonly used lenses are 3.6mm, 6mm, 8mm, etc. The 3.6mm lens shooting angle is about 90°, the 6mm lens shooting angle is about 60°, and the 8mm lens shooting angle is about 45°.

3) Signal to noise ratio

It is required to select a camera with a signal-to-noise ratio greater than 48 dB. When the ambient illumination is insufficient, the image of the surveillance camera with higher signal-to-noise ratio becomes clearer.

4) Night Vision

In order to obtain visual effects at night, it is necessary to turn on the infrared fill light at night. The selected lenses are all infrared light, and the color of the pictures taken during the day is naturally disturbed by the infrared light. If you don’t want infrared light, use a color lens that is not transparent to infrared light, the picture will be vivid and clear, but you can’t take pictures in the dark.

In principle, the car camera uses a 15-meter infrared integrated dome camera with a 15 meter night vision distance, which automatically turns on the infrared light when low illumination.

5) Power supply

The power supply is 12VDC, and the maximum current of a single camera (infrared light) requires less than 400mA.

6) Interface

In order to ensure a high-reliability connection in a harsh environment, the interface of the AV and power supply is in principle selected from the female plug of the aviation plug.

Second, the camera installation specification

1 Keep away from the heat source on the vehicle and the source of electromagnetic interference. At the same time, pay attention to waterproof, and the installation position should be protected from human damage.

2 Determine the number of installations for the installed vehicles. Position them as far as possible in a wide range of viewing angles, and try to avoid “blind areas”.

3 Please pay attention to the installation position. After adjusting the angle, tighten the lens or apply glue to prevent the lens from loosening.

4 The installation position is convenient and fixed, avoiding artificial rotation and damage to the camera, affecting the monitoring effect; installing in a place with sufficient light, avoiding installation in a dark place, enabling the infrared function to be turned on for a long time, shortening the life of the camera.

5 The installation position should be at the upper part of the carriage to avoid vandalism. If the vehicle has a lower body, the two sides of the carriage and the front and rear positions of the carriage should be installed.

6 It is recommended that each passenger bus be installed with 3-4 lenses in accordance with the condition of the door. The following is a schematic diagram of the lens installation position: (mainly considering the deployment of single and double doors

Schematic diagram of the installation of the front door of the single door

Double door installation diagram