License plate recognition (LPR) vs license plate capture (LPC)
LPR vs LPC.
There are typically two types of scenarios to consider when purchasing license plate cameras. LPR (license plate recognition) camera systems allow you to view, record, and read license plate cameras. The LPR camera or software can recognize license plates and read plate numbers to match a database or specific software function. The cost for LPR cameras can vary according to several factors including resolution, the need for the day and night scenes, lens distance to license plates, and whether you need shutter control for vehicles that are moving.
LPR is typically used in two applications. The first is to read plates entering a facility, gate, or residence when a car comes to a complete stop or is slowly moving through a specific area. These areas are normally more lit and offer better lighting and the cameras are installed fairly close to the vehicles. LPR software is then used to read and record plates to monitor visitors, residents or match license plates to local or national databases for potential criminals. LPR cameras for this scenario are typically less expensive since the cameras are installed closer to vehicles and do not often need long-range infrared, motor zoom lenses, or fast shutter speeds for moving vehicles.
The second application of LPR cameras is used to read license plates on roads or highways where vehicles are traveling at highway speeds. This application requires full-featured LPR cameras that offer advanced functions such as long-range infrared used to illuminate license plates but not overexpose the license plate or cause over-reflection. These advanced LPR cameras can capture plates both day or night while cars are moving at fast speeds, the cameras offer shutter speed controls that capture images at high rates of speed.
The second type of scenario is commonly known as LPC, or license plate capture.
License plate capture allows users to capture, record, and view license plate numbers but does not possess the character recognition functionality that allows for the plate information to be analyzed against a database. While LPR cameras detect and scan license plates that can be matched against a database or recognized by the software, LPC simply allows you to view and record the video of the license plate but LPC cannot search, recognize or scan a plate. It does not recognize plates it simply records them as part of normal video recording. Most homeowners and small to medium-sized businesses use LPC to read license plates of vehicles going in and out of their driveways, streets, and intersections, or entry/exit points, also known as chokepoints. What most consumers are looking for is a higher definition camera that will allow them to make out a license plate during playback of the recording in case there is an event and the plate information will be useful.
Pricing vs budget.
LPC is the least expensive option when you need to record license plates. A well placed high-definition camera with good focal length and field of view can easily capture license plates and record video of the plates for storage or playback later. Newer technology like Eclipse Starlight allows cameras to record video in color even at night to offer more detail and definition of license plates.
Database, white, and blacklisting.
For license plate recognition there are several software options on the market that compile a database of vehicle license plates and allow for local or national reporting. LPR or ANPR (Automatic Number Plate Recognition) software allows you to blacklist, whitelist or filter license plates based on several criteria. As an example, a private community can blacklist certain license plates based on previous visits, expelled residents or even former employees. You can even scan each plate and match the plate with a local or national police database and notify authorities the minute a plate matches their database for wanted criminals.
Type of camera to use for LPR.
Though you can use standard HD-Coax cameras like AHD, HD-TVI, HD-SDI, EX-SDI, HD-TVI, or HD-CVI for LPC or LPR, we highly recommend Signature IP cameras. Signature IP cameras offer a wide range of analytical features and advanced hardware to facilitate any of your license plate capture or recognition needs. Signature IP offers higher resolution, onboard SD card recording in the camera, and advanced programming functions that simply are not available in the aforementioned coax-based camera types.
Where to install LPR or LPC security cameras.
LPC cameras are a bit more straightforward since the objective is to capture a license plate for simple video recording and you are typically recording vehicles as they come to a complete or partial stop. For LPC it’s best to install the camera as close as possible to the vehicle’s license plate and as close as possible to vehicle license plate height. If the camera needs to be installed further away you will have to consider a camera with a varifocal lens to get a better field of view. The best camera placement is head-on to the plate or slightly off a head-on angle. The more off-center the camera placement is the harder it will be to capture the plate. Installing the camera at a horizontal angle at roughly 15-degrees and keeping the vertical angle at a max of 30-degrees is highly recommended. LPR cameras are typically used on highways, city streets, and parking lots and use camera features to offset traditional camera placement. Many LPR cameras like our Eclipse Signature long-range bullet camera allow for installations where the camera needs to be located further away from the vehicles. The long-range optics and varifocal lens allow for long-distance plate recording both during the day or night and provide more leeway for the installation.
LPR cameras lighting and recommendations.
We highly recommend using license plate cameras for the sole purpose of recording or documenting license plates and not trying to record the scene around a vehicle. This allows you to dedicate the camera settings for license plate recording or capture only. We highly recommend setting the LPR/LPC cameras to black and white at all times. This will improve the contrast of the plate characters versus the background and will increase the accuracy and reliability of license plate readings.
The faster a car travels, the faster the camera shutter speed needs to be set. As an example, if a vehicle is traveling up to 35 MPH, the camera shutter speed should be lowered to 1/30 to 1/500. As the exposure time is lowered, less light passes through the camera’s lens, and more infrared light is required. At an exposure rate of 1/500, the amount of light passing through to the camera is so very low and the video will be nearly black at night. This is why we recommend setting the camera to infrared or night mode to achieve the best results both during the day and night. Another helpful feature for license plate capture and recognition is the use of WDR or HLC. HLC or head-light compensation blocks the bright lights coming from the vehicle’s headlights so that a license plate is more easily readable. True WDR or wide dynamic range helps to equalize exposure from reflective surfaces, e.g. glare from a white truck, asphalt, mirrors. Always look for WDR and not DWDR (Digital WDR), DWDR is software-driven as opposed to the hardware-driven wide dynamic range which offers optimal performance.
As mentioned previously Starlight technology is playing a big role in LPR technology. Starlight does not require additional infrared lighting which allows license plates to be displayed in full color, even at night. Starlight is ideally suited for vehicles traveling at slower speeds.
Frame rate and speed.
Frame rate needs to be considered when trying to capture the plate from moving vehicles. The faster the cars are moving the lower the frame rate of the camera should be. We suggest that for cars from 0-25MPH that you use up to 25-30 fps. Cars from 25-40MPH use 12-15 fps and cars faster than 40MPH use 2-7 fps. Faster speeding cars will need to be played back frame by frame to view the snapshot. License plates for most cars moving at fast speeds will not be able to be seen in live mode.
Coverage of driving lanes.
Eclipse Signature cameras have been tested to cover several highway lanes at once using 3rd party VMS software partners. Our advanced hardware components partnered with VMS and LPR software allow for the best possible solution to capturing fast speeding plates over several lanes.
Eclipse Signature cameras are designed to work in extreme environments and offer IP66 and IP67 ratings. Our UL-certified products are designed to work in most city and highway environments and offer a 3-year warranty.
Eclipse Signature cameras offer vandal-proof designs (also known as IK-10, impact-resistant, vandal-resistant, or tamper-proof). Our cameras are designed to endure the elements whether natural or caused by man.
Service and maintenance.
Eclipse Signature IP LPR cameras offer motorized camera lenses that can be controlled over the internet or from your mobile phone. With defocus analytics our cameras will alert you if the camera loses focus so you can re-adjust the setting accordingly. Eclipse Signature cameras also offer firmware upgrades direct from our cloud server so you can properly maintain cameras with up-to-date firmware direct from our servers.