JP2000067163A - Method and device for detecting bus on specified route - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable improvement in discrimination accuracy without being affected by any environmental change by comparing plural template images with a photographed object and extracting the route number of the template image with the highest correlation value. SOLUTION: When detecting a bus on a specified route, the plural template images are stored by each route number in a template memory 33 correspondingly to the environmental change such as the weather, the position of the sun, time zone and the contrast based on internal illumination beforehand. Next, the field image of the route bus on a display part is periodically obtd. from a television camera 2, converted to a digital image by an A/D converter 31 and stored in an image memory 32. Next, the correlation values of the template image of the route number of the bus on the specified route obtd. by pattern matching between the image from the image memory 32 and the template image from the template memory 33 with the template image of a route number similar to the route number are compared by a route number recognizing part 34 so that the bus on the specified route can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a route number displayed on a destination display section of a route bus.

[0002]

2. Description of the Related Art In recent years, due to traffic congestion in the morning and evening, a lane on the sidewalk side is set as a priority road for a route bus, and the passage of general vehicles is prohibited. This system increases the average speed of a route bus. However, when the route bus makes a right turn, it is greatly affected by the number of vehicles attempting to make a right turn ahead of the route bus, resulting in a decrease in the average speed.

[0003] Therefore, on the right-turning lane of a route bus, the route number displayed on the destination display portion of the route bus is detected, and when the route number is recognized as the route bus turning right, a traffic light is controlled. The invention in which the route bus can be preferentially turned to the right is disclosed in, for example, Japanese Patent Laid-Open No. 10-11 / 1998.
It is disclosed in 1999 publication.

By the way, in the method of detecting a route number according to the invention in the above-mentioned conventional example, a standard template image having the same light and shade pattern as that of a destination display section of a route bus is set in advance, and the image is taken in periodically. In this method, a correlation value is obtained, and when the correlation value is equal to or larger than a threshold value, it is recognized as a destination display unit, and then a route number is recognized by extracting a numeric feature amount in a route number display area. Was.

[0005]

However, in the conventional example described above, the weather, the position of the sun, the time zone, and the shading difference due to the internal lighting (the external lighting with natural light at daytime and the internal lighting at night) are different. Due to environmental changes such as differences in shading), a very large number of different shading patterns appear in the captured image, and the correlation value fluctuates greatly. was there.

For example, when a correlation value between an image of a line number having a small difference in shading and a standard template image having a large difference in shading in a dim state is obtained, a line number is extracted from an image having a small difference in shading, or a similar value. There was also a problem that it was very difficult to identify the number.

Further, in a frame image with a period of 1/30 second, there is a problem that a blurring component caused by being a moving object is included in a photographed route number, and the determination accuracy is reduced.

An object of the present invention is to solve the above-mentioned problem. It is an object of the present invention to prepare a plurality of template images, compare them with a photographed object, and determine the route of the template image having the highest correlation value. It is an object of the present invention to provide a specific route bus detection method and apparatus capable of improving determination accuracy without being affected by environmental changes by extracting a number.

[0009]

SUMMARY OF THE INVENTION A specific route bus detecting method according to the present invention achieves the above-mentioned object, and includes means for detecting a weather, a sun position and a time for one route number of a route bus. Stores a plurality of template images corresponding to environmental changes such as differences in shading due to bands and internal lighting, and a template image of a route number in a specific route bus for a captured route number and a template image of a route number similar to the route number. By comparing the correlation values, a bus with a specific route number is detected.

It is desirable to perform template matching based on a field image, and to perform template matching only on a specific portion (a portion having a high feature amount) of a route number composed of characters and numerals by mask processing. Desirable for improvement.

Further, the means in the specific route bus detecting device of the present invention includes: a photographing means for photographing the route number of the route bus; and weather, sun position, time zone, and inside for one route number of the route bus. A template memory for storing a plurality of template images corresponding to environmental changes such as differences in shading due to lighting; a route number photographed by the photographing means; and a route number of a specific route bus corresponding to the photographed route number from the template memory. A route number recognizing unit for comparing a correlation value with a route number of the template image.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a specific route bus detecting apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is an image diagram for detecting a route number of a route bus. Reference numeral 1 denotes a route bus, and a display unit 11 on which a destination and a route number are displayed is provided on an upper front part of the route bus. Reference numeral 2 denotes a television camera disposed above a pillar 21 or the like near an intersection, which captures an image of a display unit 11 of a route bus and accommodates a detection device 3 for detecting a route number 12 of the display unit 11. I have.

FIG. 2 shows a block diagram of the detection device.
Is an AD converter for converting an analog signal from the television camera 2 into a digital signal, 32 is an image memory for storing an image (shade image data) from the AD converter 31, and 33 is a weather for each line number to be detected. , A template memory storing a plurality of template images corresponding to respective situations taking into account environmental changes such as a position of the sun, a time zone, and a difference in light and shade due to internal illumination, and 34 is an image from the image memory 32 and the template memory. This is a route number recognition unit that performs pattern matching with the template image from No. 33 and outputs the number of the route bus when a number having the highest correlation value is detected.

Next, the operation of the present invention will be described with reference to the flowchart of FIG. 3 and the method of detecting the line number of FIG. Route numbers of route buses passing through intersections are 51, 53, 57,
At 58 and 61, a description will be given of a case where priority control at the time of a right turn is to be performed on a route bus with a route number of 53 among them.

First, a field image of the display unit 11 of the route bus 1 is periodically obtained from the television camera 2 (step S1). Then, the field image is converted into a digital signal by the AD converter 31 and stored in the image memory 32 (step S2).

Next, as shown in FIG. 4, a spiral scanning is performed on the search area of the template image of "53" in the template memory 33 stored in advance in the search area centering on the coordinates where the route number is easily photographed (step S3). ).

Then, for example, it is determined whether or not there is an area having a correlation value of 60% or more (step S4).
If there is no similar image to the template image, the process returns to step S1, and if there is an area having a correlation value of 60% or more, the image of the coincident area is stored in the image memory 32.
(Step S5).

Next, pattern matching is performed between the sampling image stored in the image memory 32 and a plurality of template images of the route number 53 stored in the template memory 33 (step S6), and the correlation value in the pattern matching is determined. The highest value (for example, A) is stored (step S7).

Next, pattern matching is performed between the plurality of template images 58 similar to the route number 53 and the sampling image (step S8), and the highest correlation value (eg,
B) is stored (step S9).

Then, a correlation value comparison between the correlation value A and the correlation value B (correlation value A> correlation value B) is performed (step S1).
0) When the correlation value B is larger than the correlation value A, the process returns to step S1 or a determination is made by a mask process described later,
When the correlation value A is larger than the correlation value B, the route number is 53
Is transmitted (step S11), and is used for controlling a traffic light and the like. Note that the comparison of the correlation values in the above embodiment is the same even if the result of the subtraction of the correlation values is determined to be positive or negative.

In step S10, it is determined that the correlation value B is larger than the correlation value A, and that the common part of similar images, that is, the second digit "5" matches. In this case, the route number can be recognized by performing a correlation operation of determining whether the first digit is “3” or “8” by a mask processing method described below.

If the taken line number is "53" or "58"
If it is not possible to determine which of the numbers is “3” or “8” in the first digit, the upper and lower portions of each digit in the first digit of the template image are masked, and the number “3” or “8” is masked. A correlation operation is performed between “3” and “8” and the first digit numbers “3” and “8” in the fetched route number, and the first digit number “3” of the fetched route number is a higher correlation value. , The route number is recognized as 53, and if the first digit “8” of the captured route number is a higher correlation value, the route number is recognized as “58”. Is done. Further, the correlation of the left half of the numbers “3” and “8” may be obtained.

That is, as shown in FIG. 5, the first digit of the template image is subjected to a masking process, and a common operation with a similar image is excluded, and a correlation operation is performed with emphasis only on a characteristic portion. Accordingly, as compared with the case where the correlation operation is performed on the entire “53”, a higher correlation value is obtained when the captured image is “53”, and a lower correlation value is obtained when the captured image is “58”. Therefore, the identification becomes very easy.

In the above-described embodiment, a method has been described in which the scan number is read by performing spiral scanning with respect to the search area around the coordinates at which the route number is likely to be photographed. May be performed by another method such as a raster scan method.

[0025]

As described above, the present invention does not rely on discrimination using a single template image, but rather uses a route number of a route bus photographed by photographing means and a plurality of route numbers similar to the previously stored route number. Compared with the template image, the number with the higher correlation value is determined as the line number, so the weather, sun position, time zone, Also, even if there is an environmental change such as a shading difference between day and night due to the internal lighting, the line number can be reliably identified.

In the case of a moving object as in the present invention, by performing template matching using a field image, the image blurring is smaller than that of a frame image, and the correlation value with data closer to still image data can be reduced. High accuracy can be obtained because it is obtained.Furthermore, by performing template matching only for characters and numbers that are difficult to identify by masking, noise included in common parts can be removed and a high correlation value can be obtained. It has an effect.

[Brief description of the drawings]

FIG. 1 is an image diagram showing a relationship between a television camera and a route bus in a specific route bus detection device of the present invention.

FIG. 2 is a circuit block diagram.

FIG. 3 is a flowchart illustrating an operation.

FIG. 4 is a diagram for explaining an image captured by a television camera and spiral scanning.

FIG. 5 is an explanatory diagram showing a masking processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Route bus 11 Display part 12 Route number 2 Television camera 3 Detector 31 AD converter 32 Image memory 33 Template memory 34 Route number recognition part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koji Yamaguchi 29-1 Mita-machi, Shinoda, Miwa-cho, Kaifu-gun, Aichi F-term in the Miwa factory of Nagoya Electric Industrial Co., Ltd. 5B064 AA10 AB13 BA01 CA15 DA14 DA27 DB06 DB07 5H180 AA16 CC04 FF18

Claims (4)

[Claims] 1. A plurality of template images are stored for one route number of a route bus according to environmental changes such as weather, the position of the sun, a time zone, and a shading difference due to internal lighting.
By comparing the correlation value between the template image of the route number in the specific route bus for the captured route number and the template image of the route number similar to the route number, detecting the bus of the specific route number Specific route bus detection method. 2. The method for detecting a specific route bus according to claim 1, wherein template matching is performed using a field image. 3. The method for detecting a specific route bus according to claim 1, wherein template matching is performed on only a specific portion of the route number including characters and numerals by mask processing. 4. A photographing means for photographing a route number of a route bus, and a plurality of photographing means for one route number of the route bus corresponding to environmental changes such as weather, the position of the sun, a time zone, and a shading difference due to internal lighting. And a correlation value between the route number photographed by the photographing means and the route number of the template image of the route number in the specific route bus corresponding to the photographed route number from the template memory. A specific route bus detection device comprising a route number recognition unit.