# US 5,353,021 A · Apparatus for measuring moving state of vehicle in tunnel

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- Number: US 5,353,021 A
- Document ID: US5353021A
- Status: Granted
- Kind: A
- Application number: 07/935,283
- Filed: 1992-08-26
- Granted: 1994-10-04
- Earliest claimed: 1991-09-04
- Assignees: Matsushita Electric Industrial Co., Ltd.
- Inventors: Masakazu Toyama
- Web page: https://patentgrep.com/patent/US5353021A

## CPC

- G08G 1/04: using optical or ultrasonic detectors
- G08G: TRAFFIC CONTROL SYSTEMS (guiding railway traffic, ensuring the safety of railway traffic B61L; arrangement of road signs or traffic signals E01F9/00; radar or analogous systems, sonar systems, lidar systems specially adapted for traffic control G01S13/91, G01S15/88, G01S17/88; {radar or analogous systems, sonar systems, lidar systems specially adapted for anti-collision purposes G01S13/93, G01S15/93, G01S17/93})

## 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

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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

### Claim 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.

### Claim 6 (depends on 5)

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.