Abstract: A Doppler radar transceiver in a traffic monitoring system includes a pyramidal horn antenna having a rectangular aperture and a dielectric lens mounted at the rectangular aperture. Preferably the pyramidal horn antenna is corrugated and the rectangular aperture has a breadth at least twice its width in order to provide a fan-shaped radar beam most effective for detecting moving vehicles in a stream of traffic. To reduce standing waves in the horn antenna that would otherwise cause nulls that would intermittently interfere with detection of a Doppler signal, the dielectric lens has impedance matching means for matching impedance of the dielectric lens to impedance of free space to reduce standing waves in said horn antenna. Suitable impedance matching means include a quarter-wave transformer or a tapered transformer structure at the interfaces between the dielectric body of the lens and the free-space region inside the horn and outside of the horn.

Abstract: An apparatus of the invention includes a device for triggering a camera to photograph a vehicle within a traffic intersection, where the triggering of the camera is dependent on the speed of the vehicle before entering the intersection and may also be dependent on presence information. The device includes a sensor system (or “sensor array”) to transmit signals corresponding to a moving vehicle and a control system for processing the signals and triggering the camera. The signals preferably include “position signals” from which a transit time can be calculated, and “presence signals,” from which presence information can be obtained, particularly the location of the rear of the vehicle or the location of the rear wheels of the vehicle. A trigger time for taking a picture of the vehicle may be calculated from the transit time.

Abstract: An apparatus of the invention includes a device for triggering a camera to photograph a vehicle within a traffic intersection, where the triggering of the camera is dependent on the speed of the vehicle before entering the intersection and may also be dependent on presence information. The device includes a sensor system (or "sensor array") to transmit signals corresponding to a moving vehicle and a control system for processing the signals and triggering the camera. The signals preferably include "position signals" from which a transit time can be calculated, and "presence signals," from which presence information can be obtained, particularly the location of the rear of the vehicle or the location of the rear wheels of the vehicle. A trigger time for taking a picture of the vehicle may be calculated from the transit time.

Abstract: A traffic violation processing method is disclosed, which includes the steps of monitoring a vehicle; determining whether the vehicle is in violation of a traffic violation and recording the image of the vehicle on a camera when the vehicle is determined to have violated a traffic violation; providing a digital image of the vehicle; recording and storing deployment data corresponding to the violation, wherein the deployment data includes an identifier associated with the traffic violation; assigning the identifier to the digital traffic image; storing the digital image of the vehicle, together with the identifier, on a storage medium; matching the deployment data with the stored digital image by correlating or matching the identifier associated with the deployment data with the identifier associated with the stored digital image; and generating a traffic document that includes the stored digital image and the deployment data.

Abstract: A traffic monitoring system has a common housing for a Doppler radar transceiver, a video camera, and a digital computer for processing the Doppler signal. The system also includes a video cassette recorder, a high-speed photographic camera, and a laptop computer for downloading control settings and a program from a diskette or memory card to the digital computer. The digital computer performs an initial self-test by injecting a calibration signal in lieu of a Doppler signal into an electronic interface between the radar transceiver and the digital computer. The radar transceiver generates a Doppler signal having two channels, and the phase between the channels indicates whether a vehicle is approaching or receding from the radar transceiver. The two channels are recorded on the left and right audio channels of the video cassette.

Abstract: Frequency domain processing is used to determine rapidly whether false signals are present, and to improve the accuracy of speed measurements by rejecting speed measurements that could be inaccurate due to the presence of false signals. A Doppler signal responsive to speed of a moving vehicle is generated by a Doppler radar transceiver. A digital computer transforms the Doppler signal into a frequency domain signal such as an energy spectrum, and the speed of the moving vehicle is computed from the weighted arithmetic mean of the energy spectrum. The mean value, however, is rejected as an indication of speed if the variance of the energy spectrum from the mean exceeds a threshold, or if a differential of the spectrum with respect to frequency exceeds a threshold.