A License Plate Recognition and Speed Detection System - Index of

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specifically sold fold for license plate recognition and must be customized to be incorporated in to the LPR system. Other types of triggers include pressure sensors, infrared sensors, magnetic field detector sensors, and video cameras. Pressure sensors consist of tubes or wires that are laid across the roadway. When a vehicle rolls over the tube or wire, the pressure in the tube rises or the resistance in the wire changes, causing the sensor to output an electrical pulse. Infrared sensors use infrared light to detect the presence of a vehicle. It is similar to the sensors located on an automatic garage door opener that prevent the door from closing when an object is located under the door. The infrared sensor consists of an emitter and receiver. The emitter sends infrared light to the receiver. If the receiver does not receive the infrared light it sends an electrical pulse, signaling an object is in its path. A magnetic field detector sensor detects the presence of vehicle by the vehicle’s magnetic field. All vehicles have a magnetic field due to the large amount of metal used by them. Video cameras can also act as triggers. They can continually monitor the street and use image processing techniques to detect the presence of a moving object. For traffic violation type applications, laser range finders are mostly used to trigger the camera. There are certain specifications that are desirable for an LPR customized trigger. It is desirable to have a sensor that is unobtrusive as possible. If tubes or wires cannot be laid across the road, then pressure sensors cannot be used. It is also desirable to have a sensor with a very quick response time. Magnetic sensors may not have a quick enough response time for fast moving traffic, triggering the camera at wrong intervals. It is desirable to have a trigger that can be located near the camera. This will eliminate the need for costly extra support structures and long cable runs between camera and trigger. Some laser range finders require they be placed directly over roadways, requiring extra structures to support the system. It is also desirable to 22
choose a trigger that will require the least amount of work to be incorporated into an LPR system. Video cameras will require a computer and special software. Care must be taken to choose the appropriate trigger for the application at hand. Table 4 LPR Trigger Specifications Characteristic Desired Value Location Near camera Response time Extremely quick for fast moving traffic Obtrusiveness As unobtrusive as possible Work required to incorporate trigger in to system Minimal 23
Page 1 and 2: A License Plate Recognition and Spe
Page 3 and 4: I. Abstract Since the 1980’s law
Page 5 and 6: II. Introduction The purpose of thi
Page 7 and 8: III. License Plate Recognition Conc
Page 9 and 10: III.A. LPR Light Source There are s
Page 11 and 12: eflective paint effect greatly incr
Page 13 and 14: Uniform and Constant To be as unifo
Page 15 and 16: “Horizontal angle must not exceed
Page 17 and 18: The video camera has another compon
Page 19 and 20: width is only 5/16” will be 3 pix
Page 21: signal, such as NTSC, a capture car
Page 25 and 26: We briefly considered laser rangefi
Page 27 and 28: Fig. 17 Doppler Effect (Ref. 14) Th
Page 29 and 30: In this project, we will be using t
Page 31 and 32: V. Our System Design and Implementa
Page 33 and 34: LPR/SD System Process Flow Retrieve
Page 35 and 36: Fig. 25 Image of our LPR/SD system
Page 37 and 38: Our video camera served two functio
Page 39 and 40: V.B.2. Radar Gun The Ramsey Kit Ram
Page 41 and 42: Fig. 31 Assembled Oscillator The mi
Page 43 and 44: up to 100MHz. Once the signal has b
Page 45 and 46: I will discuss the pathway the inpu
Page 47 and 48: Fig. 35 Comparator Operation The si
Page 49 and 50: V.B.3. Serial Interface Circuit Boa
Page 51 and 52: we set pins 8 to 15 as input pins a
Page 53 and 54: Application Main Window Fig. 37 LPR
Page 55 and 56: Fig. 40 LPR.exe application windows
Page 57 and 58: Serial library was written by Ramon
Page 59 and 60: W1, B2, B3, B4, W5, B6, B7, B8, B9,
Page 61 and 62: characters were first extracted. Th
Page 63 and 64: Plate Number - 791GPB Test Results
Page 65 and 66: VI. Additional Applications The lic
Page 67 and 68: needed to communicate with the traf
Page 69 and 70: Local Network Fig. 50 LPR applicati
Page 71 and 72: VII. State of the Art Commercial Sy
Page 73 and 74:
100 MHz wide or 200 MHz wide. Since
Page 75 and 76:
As with any new technology affectin
Page 77 and 78:
law, a warrant-less crime must be c
Page 79 and 80:
experience high traffic volumes or
Page 81 and 82:
quite a fun experience to build the
Page 83 and 84:
15) Radar Setup: http://mpdc.dc.gov
Page 85 and 86:
Appendix A: Our LPR/SD System Compo
Page 87 and 88:
Appendix B: Commercial Components 8
Page 89 and 90:
MDL LaserAce® IM OEM Laser Modules
Page 91 and 92:
UF500 Infrared Illuminator 91
Page 93 and 94:
HI-TECH Solutions SeeCar Software R
Page 96:
Appendix C: Camera Setup Calculatio
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