JPS6371793A - Displaying section reading method - Google Patents

Abstract

PURPOSE:To attain displaying section reading irrespectively of the direction of a character string, by allowing the character string in the displaying section to be recognized after its direction is corrected at the time of display section recognition. CONSTITUTION:The coordinates of an already known symbol section at the edge section of a display section are retrieved on a picture and the inclined angle from the horizontal reference position of a character string in the display section is calculated based on the coordinates. Then the character string in the display section is turned to the horizontal reference position based on the inclined angle so that the display section can be read. Namely, the coordinates of an already known symbol '1' are concentrically retrieved while a retrieving radius (r) is made narrower or wider at a prescribed interval (S) from the outside or inside of a circle 48 in the quadrant, for example, the 1st quadrant, where the already known symbol character '1' exists. Then the inclined angle (U) of the display section (D) is calculated from the obtained coordinates and, when the display section (D) becomes readable, character recognition is executed by a well-known method and each character in the display section (D) is read.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a display reading method, and particularly to a display reading method that does not care about the orientation of a display character string during character recognition.

(Prior Art) Generally, a container such as a bottle has a character display such as a model number attached to the bottom of the tank for manufacturing and quality control. When automating the manufacturing and quality control of the bottles mentioned above, the problem is that because the bottom of the tank is circular, the direction of the display part of the letters, numbers, etc. representing the model number etc. cannot be determined, and it can be displayed in various directions such as up, down, left, right, etc. To lean in the direction of.

This was because character recognition technology could not be implemented.

Therefore, in order to automate bottle manufacturing, quality control, etc., the most recent efforts have been made, for example, to create a container code identification system disclosed in Japanese Patent Publication No. 81-15470, which makes it difficult for humans to identify the characters on display parts such as model numbers. However, there are some that are realized by encoding special marks.

This container code identification device is provided with a BUK detection device including a light emitting part and a light receiving part eccentrically below the axis of a container having a series of BUK codes annularly attached to the bottom surface of the container, and the mark detection device is attached to the bottom surface of the container. By rotating around the center, a ring-shaped optical scan is performed, eliminating the effect of non-directionality of the bottle, and converting the mark code into an electrical signal corresponding to the mark code, which is further understandable to humans. It is processed into a convenient shape and displayed on an external display.

(Problems to be Solved by the Invention) However, in the above-mentioned prior art method, a special mark code must be provided on the bottom of the bottle, and the manufacturing mold is completely incompatible with the conventional one, so unnecessary This results in higher costs.

In addition, in order to manage the production line, it is necessary to objectively understand the type of bottle, and humans must learn how to read the mark codes, which is extremely difficult to read directly in an instant. be.

Furthermore, you can identify the container code! 16! The system has complicated mechanical parts such as a rotating mechanism, and this is by no means the best method from the viewpoint of control and maintenance.

This invention is based on the above-mentioned r! '! + It was proposed in view of the above points, and in particular, it provides a display reading method that does not care about the direction of the character string by correcting the orientation of the character string on the display when recognizing the display. The purpose is to

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a display section reading method that captures an image including a display section using a black and white ITV camera, and performs recognition and reading of display section characters on the image. a coordinate detecting means for detecting the coordinates of the known symbol part on an image by rotationally searching a known symbol part provided at the end of the display part character string at different radii; a tilt angle detection means for detecting a tilt angle of a column from a horizontal reference position; a rotating means for rotating the display character string to a horizontal reference position based on the tilt angle; and a display character string at the horizontal reference position l. It is characterized by comprising a recognition means for character recognition of a string.

(Function) A display section of the object to be inspected is captured in an image by a black-and-white ITV camera. The orientation of the display section does not matter, and the image may be captured at an angle.

First, the coordinates of the known symbol portion located at the end of the display section on the image are searched. An inclination angle of the display character string from a horizontal reference position is calculated based on the coordinates. Next, the display character string is rotated to a horizontal reference position based on the tilt angle. This makes the display section readable and allows each character to be read and recognized.

(Embodiment) Hereinafter, a glass bottle reading device No. 11, which is an embodiment of the present invention, will be described with reference to the accompanying drawings.

Fig. 1 is a block diagram showing the configuration and usage status of a glass bottle model number reading device which is an embodiment of the present invention, Fig. 2 is a flowchart showing an example of the operation, and Fig. 3 is a display unit reading device. A flowchart showing the process. Figure 4 is a bottom view of a glass bottle where the known symbol part of the display part is a character. Figure 5 is a bottom view of a glass bottle where the known symbol part of the display part is a small dot. Figure 6 is the original screen. Figure 7 is an enlarged image of the main part showing the method for detecting the tilt angle of the character string on the display, and Figure 8 is a flowchart showing the process of calculating the tilt angle of the character string on the display. It is.

This glass bottle display reading device includes an image analysis processing section 10.
, control unit 20, black and white ITV camera 30, photoelectric switch 3
1. Illumination flash 32, external communication control unit 35, monitor 36. It is composed of a line ejector 37.

The display section to be read shows information such as manufacturing date, manufacturing mold, etc.
! ! ! This is a convex shape formed on the bottom of a glass bottle by four parts of a manufacturing mold.

FIG. 4 shows a display section in which the known symbol section K is a character. For example, is there a type in the known symbol part? Due to the image processing described later, the distance of the known symbol character "1" from the bottom center 40 is larger than the distances of the other characters r2.3J. As shown, the display section is provided eccentrically by 172 characters from the center 41 of the character string.

Furthermore, as shown in FIG. 5, depending on the configuration of the display section, '' may be provided in the convex small dots at the bottom of both ends of the display section as the known symbol section.However, in this case, the display section D The character string ' is placed in the center of the bottom.

Hereinafter, the reading process by this glass bottle display reading device will be explained in conjunction with the work situation.

As shown in FIGS. 1 and 2, the process manager first stores the model number corresponding to the display section in the model number memory 21 of the control section 20 using the external communication control unit 35 (El); If the model number has not been registered, registration of the model number is prompted before starting the device (E2).

After that, the process manager performs monitor sequence E3,
Proceed with work while monitoring and checking for poor work conditions.

Glass bottles B, which are containers to be inspected, are successively sent on the inspection line 38 through a slow cooling process after a molding process. When the glass bottle B reaches the hole 39 drilled at the inspection position of the inspection line 38 as shown in FIG. is sent to the control section 20. Based on the timing signal E4, the control fi20 executes an image capture sequence and sends an activation signal E5 to the illumination flash 32 of the light source.
send. and also sends an activation signal E5 to the image analysis processing unit 10 to operate the high-speed shutter of the monochrome ITV camera 30 via the camera control 15, and deposits the image into the image memory 11 of the image analysis processing unit IO (E6); If the image capture is not completed, it will be performed again.

Note that the black and white ITV camera 30 is a CCD type image sensor camera, (258bitX 25Bbit
).

In addition, since the image is taken from above the mouth of the glass bottle, the resulting image is inverted vertically and horizontally (Fig. 6). However, this does not interfere with the reading of the display in any way.
The advantage of this imaging method is that the bottom display section can be imaged with clearer contrast.

Next, the image analysis processing section 10 starts image processing F, that is, reading the display section, in response to the image processing activation signal E7 from the control section 20.

This image processing F will be explained according to the flowcharts of FIGS. 3 and 8.

First, the image analysis processing unit IO performs a binarization process on the (25EtbitX 256bit) image captured as described above.

Subsequently, discrete noise components from the optical system and the like included in the image are removed by a known method (Fl).

This discrete noise component is generated by variations in light reflectance, dirt, and the like.

Here, the image is reduced to 1/4 times (128bit
2Bbit) to eliminate discrete noise components from the image. After that, enlarge it by 4 times and return it to the original size by 2 times.
58 bits x 258 bits) to obtain the original image.

Since the original image is in a negative state, use F2 to invert the black and white colors.
), the display area is white and the background is black (for convenience, the sixth
In the diagram, the display area is shown in black).

Next, the image analysis processing section 10 includes a display section for the central part of the original image as shown in FIG.
128bit) Yolinal Window 4st-Jii+
As shown in FIG. 6, the window 45 is coordinated by the horizontal axis, the X axis, and the vertical axis, the Y axis. Note that the figure shows a case where the known symbol part K is the character rlJ.

A block body 47 is set on the circumference of a circle 48 in the window 45 . The circle 48 has the same radius and the distance between the known symbol portion character rlJ and the center 40, and is not particularly represented in the image.

The block body 47 is composed of 24 blocks as shown, and responds to "1" in the known symbol part, and informs the quadrant on the window in which the known symbol part character rIJ exists (G2).

As shown in the figure, by configuring the block body 47 in an annular shape having a certain width, the influence of the positional error of the display part that stops due to the SJ structure and the inspection position arrangement can be eliminated.

Next, the image analysis processing unit 10 sets "1" to the known symbol part.
” (G3).

As shown in FIG.
Within the quadrant, the coordinates of the known symbol character rlJ are searched concentrically while narrowing or widening the search radius r by a predetermined interval S from the outside or inside of the circle 48 shown in FIG. ).

From each coordinate (xi, yi) obtained in this way, the absolute value t yi/xi I of the ratio of xi and yf is calculated. Next, the coordinate 50 in FIG. Find lyi/xil at (G4).

Note that here, the known symbol part K is in the first quadrant or the third quadrant.
If it exists in the quadrant, find the maximum value, and if it exists in the second or fourth quadrant, find the minimum value.

The tilt angle U of the display section is calculated by the image analysis processing section 10 as follows based on Iyi/wit obtained as described above.

First, the apparent inclination angle 01 is 01=j an-117i/nil when the known symbol part K exists in the first quadrant, and DH=90'-t an- when it exists in the second quadrant. 11yi/xil+90c'
, if it exists in the third quadrant, θ+ = j an-117i/xil+180', the fourth
If it exists in the quadrant, θ+ = 90'-t an11yi/xil+270°
, is calculated by .

Subsequently, the initial angle θ0 shown in FIG. 7 is subtracted from the apparent inclination angle 01 to obtain the inclination angle U (G5).

Next, the image analysis processing unit 10 rotates the window 40 by the tilt angle U using a known method, so that the character string on the display unit is placed in a horizontal reference position, that is, parallel to the X axis (G6).

In addition, even when the known symbol part shown in FIG. Rotate the next string to the horizontal reference position.

However, in step 03 of the flowchart of FIG. 8, the coordinates '' are searched for both small dots, and the inclination angle U is calculated based on the ' coordinates of both small dots. Therefore, this method has the advantage of increasing the calculation accuracy of the tilt angle U and, in turn, improving the reading force of the display unit.

Next, when the display section becomes readable as described above, character recognition is executed by a known method to read each character on the commercial and industrial display section.

First, according to the feature extraction method using projected side features, an X-axis direction density histogram and a Y-axis direction density histogram are obtained from each character on the display section (FIG. 3, F3).

Next, compare each density histogram of the second digit character "2" with each density histogram from 0 to 9 stored in the data memory 12 (F4). Select the relevant candidate (F5). If there are multiple candidates, perform feature extraction again (F6). Then, perform the same process on the third digit character "3" as for the second digit. (F7).

Next, when the image processing unit 10 completes the image processing as described above, an image processing completion signal F is sent to the control unit 20.
8 is sent, and together with this, the display part character signal (1) is sent to the control section 20.

The control unit 20 compares the display part character signal stored in the memory 22 with the registered model number stored in the model number memory 21 to determine whether the display part character signal is the same as the registered model number (A9 in FIG. 2). In other words, if it is a registered type of glass, it will be displayed as GOOD on the monitor (Al0), and if it is a different type of glass, it will be displayed as >IC (A11), and if the glass is of a different type, %3B will be discharged from the line by the control unit 20. Vessel 37
is activated and discharged. Subsequently, the next new piece of glass blocks light from the main switch 31, and the display is read by the process described above.

The above-mentioned operations are performed continuously, and the read display section information is subjected to statistical processing, etc., and manufacturing and quality control are automatically performed. In addition, by combining multiple devices, various line systems can be created on lines where multiple types of glass bottles are transported. can be done.

(Effects) As illustrated and explained above, the present invention provides a display reading method in which an image including a display is captured by a monochrome ITV camera, and characters on the display are recognized and read on the image. a coordinate detecting means for detecting the coordinates of the known symbol portion on the image by rotating and searching the provided known symbol portion at different radii; and a coordinate detecting means for detecting the coordinates of the known symbol portion on the image; The apparatus comprises: a tilt angle detection means for detecting a tilt angle; a rotation means for rotating the display character string to a horizontal reference position based on the tilt angle; and a recognition means for character recognition of the display character string at the horizontal reference position. This is a characteristic feature.

According to this invention, even if the display section is provided on a non-directional surface such as that seen on a bottle, by calculating the inclination angle of the display section on the image and rotating the image, Character recognition technology can be used. Therefore, the format of information representation between the display reading device and humans is compatible, and a manufacturing line that is extremely easy to manage can be realized.

As a result, mark encoding on the display, which was previously necessary,
This also avoids complicating the mechanism of the device, making a great contribution to the industrial field.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration and usage status of a glass bottle model number reading device which is an embodiment of the present invention, Fig. 2 is a flowchart showing an example of the operation, and Fig. 3 is a display unit reading device. A flowchart showing the process. Figure 4 is a bottom view of a glass bottle where the known symbol part of the display part is a character. Figure 5 is a bottom view of a glass bottle where the known symbol part of the display part is a dot part. Figure 6 is the original screen. Figure 7 is an enlarged image of the main part showing the method for detecting the tilt angle of the character string on the display, and Figure 8 shows the process of calculating the tilt angle of the character string on the display. It is a flowchart. lO...image analysis processing unit, 20...control unit, 30.
...Black and white ITV camera, 31...Photoelectric switch, 32
...Lighting flash, 35...External control unit, 45...Window, B...Glass paddy, D
...Display section, K...Known symbol section, U...Tilt angle. Figure 3 Figure 4 Figure 6 Figure 5 [''1 Figure 7

Claims (1)

[Claims] 1. A display reading method in which an image including a display is captured by a black-and-white ITV camera, and characters on the display are recognized and read on the image, comprising the steps of: Coordinate detection means for detecting the coordinates of the known symbol portion on the image by rotating and searching the symbol portion at different radii; and a tilt angle for detecting the tilt angle of the display character string from the horizontal reference position based on the coordinates. A display comprising a detection means, a rotation means for rotating the display character string to a horizontal reference position based on the inclination angle, and a recognition means for character recognition of the display character string at the horizontal reference position. How to read the section. 2. The display section reading method according to claim 1, wherein the known symbol section is an information character such as a model number. 3. The display section reading method according to claim 1, wherein the known symbol section is a dot section.