Apparatus for measuring moving state of vehicle in tunnel

• US 5,353,021 A
• Filed: 08/26/1992
• Issued: 10/04/1994
• Est. Priority Date: 09/04/1991
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Toyama, Masakazu
• Primary Examiner(s): Hofsass, Jeffery A.
• Application Number:
  US07/935,283
• Time in Patent Office: 769 Days
• Field of Search: 340/937, 340/933, 340/936, 382/50
• US Class Current: 340/937
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

An apparatus for measuring a moving state of a vehicle in a tunnel, in which traffic information such as number of vehicles which have passed, velocity, and the like can be always accurately measured without being influenced by changes in brightness in the tunnel. The measuring apparatus has an image pickup device installed in the tunnel and an image processing device for processing image data generated from the image pickup device. The apparatus further includes an input device for receiving a brightness/darkness signal which is changeable to adjust brightness of an illuminating apparatus installed in the tunnel, and adjusting device for adjusting an operation of the image pickup device or an operation of the image processing device in accordance with a change of the brightness/darkness signal, thereby preventing possible errors caused in the measurement.

Claims

1. An apparatus for measuring a moving state of a vehicle in a tunnel, the tunnel having an illumination light source installed therein, illumination brightness of the illumination light source being adjusted by an externally applied brightness/darkness adjustment signal, said apparatus comprising:

image pickup means, installed in the tunnel, for generating image data of the vehicle;

image processing means for processing the image data to determine a state of the vehicle;

input means for receiving said externally applied brightness/darkness adjustment signal; and

adjusting means for adjusting data generating operation of said image pickup means or data processing operation of said image processing means in dependence upon said brightness/darkness adjustment signal.

2. An apparatus according to claim 1, wherein said adjusting means is adapted for adjusting a diaphragm of said image pickup means.

3. An apparatus according to claim 1, wherein said adjusting means is adapted for adjusting a conversion level of an analog/digital converting section included in said image processing means.

4. An apparatus according to claim 1, wherein said adjusting means is adapted for adjusting a threshold value of said image processing means.

5. An apparatus for measuring a moving state of a vehicle in a tunnel, the tunnel having an illumination light source installed therein, illumination brightness of the illumination light source being adjusted by an externally applied brightness/darkness adjustment signal, said apparatus comprising:

image pickup means, installed in the tunnel, for generating image data of the vehicle;

image processing means for processing the image data to determine a state of the vehicle, said image processing means comprising memory means for storing a plurality of background data sets of said tunnel in accordance with various possible brightness/darkness adjustment signals;

input means for receiving said externally applied brightness/darkness adjustment signal; and

adjusting means for adjusting data generating operation of said image pickup means or data processing operation of said image processing means in dependence upon said brightness/darkness adjustment signal, said adjustment means selecting one of the stored data sets in accordance with said brightness/darkness adjustment signal received by said input means.

6. An apparatus according to claim 5, wherein:

said memory means includes first memory means for storing each frame of image data generated by said image pickup means and second memory means for storing said sets of background data; and

said image processing means further comprises;

data processing means for evaluating the brightness/darkness adjustment signal received by said input means and enabling selection by said adjusting means of one of the background data sets stored in said second memory means, and

means for producing difference data of (a) image data stored in said first memory means and (b) the one of the background data sets selected by said adjusting means to thereby extract possible vehicle data and measure a moving state of the vehicle.