License plate recognition software (SOFTWELL) for parking lot management program
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I. Overview
The current parking lot management system is mainly based onRadio frequency cardOr bar code labels are used as the medium to manage the entry and exit of the car. Some systems have the function of image collection, which collects pictures when the car enters and exits for manual comparison and archiving.
At present, our license plate recognition software can be used inparking lotUsed in the management system and played a huge role. The recognition software is used in the form of DLL, which can be seamlessly embedded in the parking lot application management software. It only needs to add the code (various development software) we have written and recompile it. Development supports a variety of commonly used development tools such as VC++, BCB, VB, and Delphi.
The advantage of license plate recognition is that it can correspond to the card and the car, so that the management can be improved to a higher level. The advantage of the correspondence between the card and the car is that the long-term rental card must be used in conjunction with the car, eliminating the loopholes in the use of one card and multiple vehicles, and increasing the collection of parking fees ; At the same time, it automatically compares incoming and outgoing vehicles to prevent theft from happening. The upgraded camera system can collect clearer pictures and save them as files, which can provide strong evidence for some disputes.
Second, the system process
2.1 Car entry: The software performs license plate recognition while reading the card (card taking). There is one more recognition process than the original software.
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2.2 Car driving out
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3. SOFTWELL license plate recognition SDK software
The following is the description of the C language calling function interface. (omitted)
Four, related hardware introduction
4.1 Camera: In the same environment, a camera with good performance can collect clearer pictures, and the recognition rate of the system is high. Generally, a camera with a 1/3 target surface can be used, and the shutter can be set to 1/250~1/500, and it cannot be set too low, otherwise it will not be able to shoot clear moving objects; the aperture adopts an automatic aperture. It is recommended to use manual focus. For projects with poor environment, such as backlight photography, open entrances and exits, etc., in order to improve the recognition rate of the system, a camera with 1/2 target surface can be used.
In particular, the wide-dynamic camera, which is currently commonly used for road monitoring, is also recommended.
4.2 Lens: fixed focus lens matched with the camera is adopted. Different cars have different sizes. When taking pictures, the car license plates are in different positions. The size of the license plate in the picture is not fixed, but within a range, so it is recommended to use a zoom lens to test in advance and roughly determine the focal length. , You can use a suitable fixed focus lens, such as: 5~50 10 times lens can basically be used in various projects.
4.3 Image acquisition card: It is recommended to use a PCI image acquisition card, usually a single-channel acquisition card with two switching inputs. If real-time image monitoring is not required, generally one card can be used for one-in and one-out systems. A single computer supports up to 12 channels. If you need to monitor the screen in real time, you can insert 2 or more cards to solve the problem. It is recommended to use an image capture card that can capture 768X576 size, which can improve the recognition rate of the system.
4.4 Computer: The manned parking lot does not have high requirements for computers, and commercial computers can be used. However, it is recommended to use the XPE embedded windows operating system to increase the startup speed of the system and improve the stability of the system. In an unattended environment, it is recommended to use an industrial computer. The operating system adopts an XPE embedded system. Industrial computers usually have a watchdog function, which can effectively improve the stability of the system.
4.5 Supplement light: It is recommended to use flash or LED license plate supplement light at night or when the light is insufficient. For a completely grounded parking lot, the ambient light source needs to be turned on at night. Our company provides LED fill light with good effect.
Five, matters needing attention
5.1 The license plate in the collected image should be as clear as possible and kept level. The number of pixels occupied by the license plate should be between 110 and 160, with around 160 being the best.
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5.2 If the entrance and exit card swiping position is completely in the basement, and there is no backlighting, the system is relatively easy and the recognition rate is high. A more economical camera system can be used. Because the outside light of the ground parking lot is constantly changing, a camera with better performance should be used, and supplementary light equipment should be added according to the situation. The work of system debugging will increase, and the cost should be increased relative to the underground parking lot.
5.3 As an interlaced camera is usually used, it is necessary to sample the image of the moving object in order to obtain a clear image. Our company provides free image sampling procedures.
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5.4 It is recommended to adopt the scheme of photographing the front plate of a car, because the position of the front plate is relatively fixed, but it is difficult to fix the position of the rear plate. It is difficult for the camera to take pictures of the rear plate of a small car and a large car at the same time. . In addition, in some trucks, the rear license plate is easily blocked by cargo and bumpers in many cases.
Some underground parking lots can only allow cars and vans with less than 9 seats to enter. At this time, you can also consider taking a poster.
5.5 The recognition software can give the confidence of the recognition results of each Chinese character, letter and number, so it is recommended to use fuzzy comparison when entering, such as continuous three-digit comparison, etc., and there is someone on duty at the exit In the case of, a stricter comparison method can be used.
5.6 The recognition trigger signal adopts the card swiping signal, which means that the image recognition is taken immediately when the card is swiped, and the whole process will not exceed 1 second.
5.7 The SDK of the capture card should support the image capture in the memory and recognize it in the memory. Generally, it is not recommended to save it as a picture before recognizing the picture file. After the recognition is completed, the pictures in the memory can be saved as JPG files to save hard disk space.
6. Products and services provided
6. The complete set of products includes:
One single-channel image capture card and one drive software encryption lock (parallel port or USB port), drive software, and SDK software package
Recognize the test software through the capture card
Chinese character training program
VC++, BCB, VB, Delphi recognize the source code of the picture DEMO program.
6.2 Provide free technical support and lifetime free upgrade service.
6.3 Provide customized development of OEM software.
6.4 Provide free software trial test program.
Seven, similarParking lot system
Including car toll stations, car weighing systems, car inspection lines, car yard management and so on. It may be different in the recognized trigger signal method.
8. Derivatives
Including container number recognition, vehicle type recognition and so on.
Nine, contact us
Company: Shenzhen Sowell Technology Development Co., Ltd.
Contact: Mr. Zhang
Phone: 0755-26001736 13717143112 QQ: 291399854
website: http://www.cnsoftwell.com
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