Precautions for Installation of Parking Lot License Plate Recognition System

In the intelligent parking lot system industry, the license plate recognition system is a relatively advanced intelligent parking lot charging system. It uses the license plate recognition technology, which is highly intelligent, easy to use and safe, and is welcomed by the market. However, the license plate recognition system is greatly affected by environmental factors. If the environmental conditions are not suitable, the system will not operate normally. Therefore, when we install the license plate recognition system, some on-site environments need to be tested.

The all-in-one license plate recognition machine can quickly and accurately output the license plate recognition results, and it is very important to capture high-quality license plate images. Therefore, when selecting the device orientation of the all-in-one license plate recognition machine, the main policy is to make the all-in-one machine capture intact and clear license plate images. By situation:

1 Straight lane device straight lane is an ideal device environment, and vehicles can obtain high-quality photos when driving into the identification area. 1. During construction, the integrated license plate recognition machine and the road gate can be installed on the same side of the lane, but the integrated license plate recognition machine should be installed in front of the road gate at an interval of not less than 30cm to prevent mutual interference between equipment. 2. When capture identification and video identification are selected, the best interval of the ground induction coil interval integrated machine is 4m; 3. When the video plus ground induction recognition mode is selected, the best interval of the ground induction coil spacing all-in-one machine is 3M.

2 Wide lane device 1. If the lane is extra wide and the traveling direction of the vehicle is not fixed, when the vehicle enters, the front of the vehicle will skew left and right, which simply affects the identification function. It can divide two lanes, or block a non motorized lane with cone barrels, road piles and other obstacles, so as to narrow the motorized lane and straighten the driving direction. 2. If the lane is very wide, but can not be separated into two lanes or add non motorized lanes, in this case, double cameras can be installed, that is, an all-in-one license plate recognition machine can be installed on both sides of the lane, so that the license plate can be photographed and recognized by the camera no matter which side the vehicle direction is inclined. 3. If the lane is very short, when the car comes from a certain direction, the body is generally inclined to one side. In this case, the camera can be installed on the side of the front of the car, so the front of the car is facing the camera when taking photos; If the vehicle comes from two directions, double cameras can be installed, and each camera can take pictures of the incoming vehicle in one direction

3 Curve device when the curve device is equipped with license plate recognition equipment, the vehicle direction points to the outside of the curve, so the integrated license plate recognition machine should be installed on the peripheral side of the lane, so that when the vehicle drives into the recognition area, the priority parking camera can take more positive license plate photos.

4 When the basement device needs to install the integrated license plate recognition machine in the basement, it needs to follow the following criteria: the integrated license plate recognition machine at the entrance is installed on the horizontal road above the basement ramp, and the integrated license plate recognition machine at the exit is installed on the horizontal ground below the basement ramp. In this way, it can prevent the doubt that the vehicle can only stop on the basement ramp when the all-in-one machine can't recognize the license plate, resulting in the gate can't lift the pole.

Before system installation, it is necessary to specify:

1. Installation position of gate and all-in-one machine

The installation position of the gate and the all-in-one machine is very critical, because it involves the convenience of users. Generally speaking, the distance between the road gate and the integrated machine shall not be less than 0.5m. It is better to install the camera on the safety island near the lane in front of the road gate host. The principle is that the camera does not extend out of the safety island and close to the road gate host but does not affect the use of the road gate. At the same time, avoid the pole blocking the camera lens during taking off and landing.

The width of lane is also a consideration for the installation of gate and integrated machine. The width of lane should not be too wide, which will affect the identification of vehicle access. It is recommended that the width is less than 3.5m.

2. Installation height of surveillance camera and dimensions of safety island

The viewing angle range of the surveillance camera shall cover the position of the vehicle license plate, and the installation height is generally 0.5-1.5m. The best identification distance is 3 4m, and the size of the safety island is more than 5.5m.

3. Installation position of sentry box

The parking lot sentry box plays the role of charging and management, and is generally installed at the exit. The sentry box is a small office, which is generally equipped with personnel on duty and management computers. Therefore, there are certain requirements for the area, which is generally not less than 4 square meters.

4. Manage where your computer is installed

The general computer of license plate recognition parking lot system management is generally placed in the sentry box or other management office. The requirements for the installation position are: the distance between the computer and the equipment shall not exceed 70m. If it exceeds 70m, it is recommended to use single-mode four core optical brazing for connection, and the network cable connecting the equipment shall be category 5 network cable.

The following are the design and installation requirements of license plate recognition system:

1. Standard lens 5mm; The correlation between the linear distance (m) and the pixel (P) of the license plate is sorted as follows:

2. Standard lens 4mm; The correlation between the linear distance (m) and the pixel (P) of the license plate is sorted as follows:

Small license plate recognition (90-120 pixels), large license plate recognition (120-160 pixels). Full resolution capture of the on-site vehicle photo triggering the ground feeling, and the width of the license plate (the pixel size of the license plate can be displayed by framing the license plate through the drawing software).

The best straight-line distance: the straight-line distance from the camera lens to the outer side of the ground sense, generally about 5m for 5mm lens and about 4m for 4mm lens.

1. Erection height of all-in-one machine: generally 1.5m-1.8m;

2. Camera column: installed inside the gate, about 50cm away from the gate rod; Prevent the gate rod from blocking the camera capture, thus affecting the recognition effect;

Wiring: network line, power line, ground sensing switching value signal line (connected to vehicle inspection output terminal).

3. Ground sensing position at the entrance and exit: the length of the integrated machine occupies 0.5m, which is calculated according to the Pythagorean law (A2 B2 = C2):

1) The horizontal distance between the camera lens with 5mm lens and the brake rod shall be kept at about 4.3m. If the camera height exceeds 0.5m, it should be reduced by about 0.25m.

2) The horizontal distance between the camera lens with 4mm lens and the brake rod shall be kept at about 3.2m. If the height exceeds 0.5m, it should be reduced by about 0.25m.

4. Position of deceleration belt: it is installed at about 1m outside the ground feeling at the entrance and exit to ensure that the following car does not touch the ground feeling. In order to prevent the owner from following the car too close, a warm prompt board should be erected and kept 3 meters away.

5. Fill light: the column is 0.6m high and installed at 50cm-80cm on the inner side of the ground sensor (keep the fill light on the front of the license plate). It can be reflected on the license plate by shooting on the ground sensor coil to ensure the recognition effect of the license plate.

6. Monitoring picture (bottom inclination): try to keep the width of the license plate parallel to the horizontal, with a maximum of 15 degrees.

Therefore, the system requirements can lead to the requirements of the system for the on-site environment. In addition, according to the problems encountered in other projects, the following points are specifically summarized:

1. When the vehicle enters the image capture area, the vehicle is facing the camera, and the effect is the best.

2. The place where license plate recognition is installed shall have sufficient straight-line distance to facilitate installation and commissioning. This distance can be calculated as follows (vehicle length best recognition distance of camera).

3. Avoid installing license plate recognition system equipment after 90 turning.

4. Avoid installing license plate recognition system equipment on uphill and downhill.

5. The system shall be installed to avoid the chaotic environment on site (there are many pedestrians, and pedestrians often enter and leave the vehicle passage, which is easy to cover the license plate).

6. Avoid the channel with serious water and sewage on the road when it rains (it is easy to block the license plate).