License Plate Recognition (LPR) Cameras

What Is an LPR Security Camera and How Does It Work?

An LPR is a license plate recognition system that is also known as character recognition. This camera operates as an advanced traffic sensor designed to capture and interpret digital images — the numbers and letters — of license plates with exceptional precision and speed. They are ideal for cars moving at speed and work well with the license plate material.

The images LPR cameras produce are way clearer than regular cameras. License plate reading cameras process images in real time, meaning they can capture, analyze, and interpret license plate data within milliseconds.

Hardware

Optiview offers LPR cameras that are capable of recording at high enough frame rates and shutter speeds to cleanly capture license plate cameras in live view and playback, as well as true ANPR license plate cameras, which add license plate tags to a database onboard a network video recorder (NVR).

Software

We also offer software solutions, using special analytics software for more advanced license plate capture with platforms such as Digifort.

Level One

Level one is ideal for gated entrances, parking garages, and controlled or confined entrances.

Good lighting, slower traffic, and the ability to mount the camera within 15 to 25 feet of the vehicle create a perfect environment for license plate recognition. This setup could easily put you into one of Optiview’s entry-level solutions.

Since the vehicles are both moving slower and located closer to where you mount the camera, we do not have to worry as much about specific technical details such as shutter speeds of the cameras or high-intensity LEDs for long-range infrared (night vision). If the jobsite has ample lighting, we expect the camera to stay in full color. If it gets dark, you will need infrared (IR) for night vision.

Jobsite considerations include:

1. Are the vehicles traveling at speeds under 25mph?
2. Are you within 15-25 feet of the license plate?
3. Are you at a less than 45° angle from the license plate from where the mounted camera is? We must receive the infrared reflection from the license plate and that it is not reflecting elsewhere but feeding back to the camera.

If you answered ‘yes’ to the above three questions, a high-quality long-range LPR camera from Optiview may be able to handle this workload using traditional full-color or negative-image LPR cameras. As they are video storage only, you can pair these license plate cameras with a plug-and-play digital video recorder (DVR) or network video recorder (NVR).

These are available in both Internet protocol (IP) and Coax technologies.

Level Two

Level two is for faster rates, such as faster-moving traffic or multi-lane.

In this environment, we need a camera that can perform at a higher shutter speed and that you can adjust. We will also need a camera with higher-intensity light-emitting diodes (LEDs) for higher-quality night vision. This higher-intensity LED will give us more feedback from the license plate.

The higher shutter speed combined with higher-intensity LEDs (infrared) allows light to reflect off the license plate and feed the recorder back the negative image of the characters on the tag. LPR-specific cameras will typically have a much higher shutter speed than standard surveillance cameras, which means we can capture the license plate moving at a higher rate of speed.

Due to the higher technology built into this license plate camera reader, it is important to ensure your DVR/NVR can perform and keep up with the capture rate (frames per second / pictures per second) and resolution. Your DVR will be the tool you use to play the video back from an event and read the characters on the license plate frame by frame.

Since this camera will only display in black and white (showing a negative of the license plate), most customers will install a secondary surveillance camera that records in color and has a wide-angle view. That way, you have one camera working to retrieve the color and description of the vehicle and occupants, and the license plate camera is solely for capturing the license plate data.

Level Three

Level three is for adding analytics for ANPR, which is ideal for searching tags and capturing data.

This approach takes everything we discussed in Level 2 and adds LPR Software. Optiview’s LPR software can be Linux-based on our AI servers or standalone PC-based using a third-party LPR program. Discussing your individual needs with an Optiview Account Manager is always best to determine which solution is best for you or your customer.

Analytics software for LPR cameras will take the live video image of the license plate and convert it to text that then becomes searchable data. This data can then be set up for future alerts, notifications, or actions. Our software will allow you to type in a complete or partial tag number, and the software will find any video events that match the query.

Example: You type in Tag # ABC 123 in the search query. A list of video events where Tag # ABC 123 appear. You can now click on any of those events and view the video footage of that event as they passed through.

Usually, our customers will use this search feature to find a general list of times when a vehicle comes and goes. They then use this data to play back video from other cameras in that area to get a more complete view of the situation.