Communications: electrical – Traffic control indicator – Combined
Reexamination Certificate
1997-01-30
2003-03-25
Wu, Daniel J. (Department: 2632)
Communications: electrical
Traffic control indicator
Combined
C340S937000, C340S939000, C235S384000, C348S148000, C701S117000
Reexamination Certificate
active
06538579
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a moving object detection method and apparatus for detecting moving objects, such as vehicles, using remote sensing techniques.
2. Description of the Prior Art
In a known system that debits tolls against vehicles traveling a toll road (refer to Japanese Patent Laid-Open Publication No. Hei 4-34684), the entering of a vehicle into a tollgate is optically detected, a toll bar is lowered at the exit of the gate at least until payment of the toll, and the toll bar is raised after confirmation of the toll payment. The greatest disadvantage of this system is that gates must be provided.
SUMMARY OF THE INVENTION
One motive of the present invention lies in solving the above-mentioned problem of the conventional system while another lies in improving some of the functions of an automatic debiting system (referred to as a “previously proposed system”) proposed earlier by the assignee of the present application in Japanese Patent Application No. Hei 7-82523 and its corresponding U.S. patent application Ser. No. 08/661,703 now U.S. Pat. No. 5,602,395.
Solving the problem of the previously proposed system, which is the first motive, has already been achieved in the previously proposed system. In the previously proposed system, a gantry spanning a road is provided, and debiting against vehicles and debiting confirmation are executed through radio communications between antennas installed on the gantry and in-vehicle units (IU) in vehicles. Therefore, in the previously proposed system, it is not necessary to provide gates, thus resulting in such advantages as reductions in facility installations and maintenance costs, and prevention of traffic bottlenecks by allowing free lane travel. Furthermore, in operating an automatic debiting system, it is necessary to manage the system so that debiting is performed fairly against all vehicles traveling on the road. In the previously proposed system, steps can be taken to detect vehicles, such as those not carrying an IU, those carrying an IU for another vehicle type, or those for which payment was insufficient (collectively referred to hereinafter as illegal vehicles), and photograph their license plates. In this respect, the system management based on the above-mentioned object is satisfied. One method that is particularly effective in this respect among the various characteristic configurations in the previously proposed system is to detect vehicles using remote sensing techniques, and based on the result compared with that of debiting and debiting confirmation, to detect the various types of illegal vehicles. Specifically, the previously proposed system proposes a method for detecting positions where vehicles are located along a direction traversing the road, and to provide information, such as their detected positions (referred to hereinafter as “detected vehicle positions”) and their sizes (vehicle widths), for comparison with results such as debiting.
One point that must be taken into account when detecting, for example, the positions of vehicles along the direction traversing the road is false detection caused by any of a variety of factors. For example, if various types of noise (including factors caused by an operation or performance of vehicle detection devices, factors caused by interference among vehicle detection devices, and factors caused by environmental conditions of rain, snow, light, temperature, dirt, birds, and so forth) are generated during detection, false detection may result, such as objects other than vehicles being detected as vehicles or a single vehicle being detected as multiple vehicles. Furthermore, if an attempt is made to detect the positions of vehicles at a high resolution, for example, the likelihood of an above-mentioned noise-induced false detection generally increases and other errors become probable, for example, the detection of part of a vehicle, such as the angle or framework of a trailer's rear, a mirror protruding from the side of a vehicle, or the outline of a vehicle having a complex profile in the horizontal plane, as second vehicle. Furthermore, when multiple vehicles travel side by side in close proximity to each other, it is also possible for these vehicles to be falsely detected as a single vehicle.
One object of the present invention lies in reducing or preventing false detection when detecting moving objects, such as vehicles, with sensors, such as distance sensors, by processing the positional information obtained from the concerned sensors using the profiles, movements, and so forth, of the moving objects.
A first aspect of the present invention is a moving object detection method and a second aspect is a moving object detection apparatus. In the first aspect, a process for detecting the existence of moving objects at multiple positions on a predetermined line by scanning on the concerned line, and a process for filtering moving object existence information obtained from this detection with filtering characteristics determined according to essential profiles of the moving objects and/or to moving object information obtained in a previous period are executed periodically. In the second aspect, the existence of moving objects at multiple positions on a predetermined line is periodically detected by scanning on the concerned line with sensors, and the moving object existence information obtained from the sensors at a certain period is filtered with filtering characteristics determined according to essential profiles of the moving objects and/or moving object information obtained in the previous period.
In the present invention, the original moving object existence information obtained from scanning and detecting on the line comprises information indicating whether or not a moving object exists at certain positions on the line. The original moving object existence information usually is susceptible to the effects of various types of noise, parts of vehicles (such as mirrors), moving conditions of the moving objects (such as traveling side by side), and so forth. Therefore, if the original moving object existence information is used as is, conditions, namely, false detection, may occur where the obtained information indicates with regard to a certain position, “a moving object exists” even though moving objects do not actually exist at that position (or should not be considered to exist), or “a moving object does not exist” even though a moving object actually exists at that position (or should be considered to exist). The moving object existence information is filtered in the present invention to reduce the risk of false detection caused by the effects of various types of noise.
In the present invention, the filtering characteristics for use when filtering the moving object existence information are determined, for example, according to the essential profiles of moving objects. If the moving object existence information is filtered with filtering characteristics determined according to the relevant information, it becomes possible, from viewing the essential profile of a moving object, to correct the information when it was obtained indicating “a moving object exists” at a position where it should originally be “a moving object does not exist” to information indicating “a moving object does not exist,” and conversely, to correct the information when it was obtained indicating “a moving object does not exist” at a position where it should originally be “a moving object exists” to information indicating “a moving object exists.” Or, the filtering characteristics in the present invention may be determined according to the moving object existence information that was obtained in a previous period. If the moving object existence information is filtered with filtering characteristics determined according to the relevant information, it becomes possible, from viewing the continuity that should be maintained with the moving object existence information in a previous period, to correct the information when it was obt
Sunahara Shuichi
Yoshikawa Kazutoshi
Toyota Jidosha & Kabushiki Kaisha
Wu Daniel J.
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