JPH1091837A - Device for detecting edge of object to be identified - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the picture blur of a screen, and to average the picture blur in vertical and horizontal directions by arranging a CCD(charge coupled device) sensor to be inclined to the transferring direction of a coin. SOLUTION: A coin 2 is transferred to the face of a glass 24 by a belt or a rubber roller, and an angle D made by a transferring direction F and a center line R of a CCD sensor 23 is set 45 deg.. The circular coin 2 is irradiated with a dark field light at a shallow angle, and an obtained reflected light is transmitted to the CCD sensor 23. Second-dimensionally arrayed pixels are scanned to a horizontal direction and a vertical direction, and photoelectric conversion is operated. Thus, picture blur can be reduced on the screen of the CCD sensor 23, and the picture blur can be averaged in the vertical and horizontal directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge for detecting an edge position of an object to be recognized from a result obtained by imaging an object to be recognized such as a coin transferred in a predetermined direction by a CCD sensor and performing luminance projection. The present invention relates to a detection device.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional circuit configuration of an edge detection device for an object to be recognized. This circuit configuration includes a scanner unit 1, a control unit 10, and a monitor 12. As shown in FIG. 7, the scanner unit 1 irradiates the coin 2 which is a circular object with the light from the light source 25 through the lens 3 toward the edge of the coin 2. In this irradiation, the coin 2 is irradiated with the dark field light 4 at a shallow angle, and the obtained reflected light 5 is sent to the CCD unit 7 through the optical system 6. CCD unit 7
Is constituted by a CCD sensor 33 composed of a CCD (charge coupled device), as shown in FIG. Figure 10 shows a CCD
Indicates the imaging surface of the sensor 33, and n
A large number of square-shaped light receiving portions of rows × m columns are formed from pixels 34 arranged two-dimensionally.

[0003] Such a two-dimensionally arranged pixel 34
Scans the image in the horizontal and vertical directions, sequentially performs charge transfer, and performs photoelectric conversion for extracting an analog image signal corresponding to input light. The photoelectrically converted analog image signal is amplified by the amplifier 8 and the amplified image signal is A / D
The signal is converted into a digital signal via the converter 9 and becomes an output signal. The digital signal is taken into a frame memory 11, and a series of image processing for feature extraction is performed by a control unit 10 to perform identification determination.

In the circuit shown in FIG. 7, a circular object such as a coin is projected in a horizontal direction and a vertical direction onto a frame memory 11 based on the reflected light received from the object 2 in each direction. An edge point which is a boundary of an object is obtained, and the center coordinates are further calculated. One row (horizontal direction) on a two-dimensional square matrix (n × m)
Alternatively, the luminances of all the pixels in one column (vertical direction) are added to obtain a histogram. From this histogram, a horizontal luminance projection and a vertical luminance projection are obtained.
Next, for each luminance projection, scanning and detection are performed using horizontal and vertical scanning lines. Then, a reference point where each scanning line exceeds the threshold value of the luminance projection is selected, and an intersection point where each scanning line in the horizontal and vertical directions intersects with each distribution line of the luminance projection is detected, and an edge point in each direction is detected. Seeking.

In the above-described configuration, the conventional edge detecting device, as shown in FIG. 9, uses the CCD sensor 33 when the coin 2 is transported in the F direction on the surface of the glass 24 by a belt or rubber roller (not shown). Are arranged in parallel with the transport direction F. 26 indicates a case.

In this case, the strobe light is emitted and coin 2
Is captured by the CCD sensor 33. However,
When the movement of the coin 2 changes due to uneven transfer speed of the belt or the roller, image blur in the vertical direction has occurred. For this reason, an error occurs in the size and center position of the coin, and the reliability of coin discrimination has been reduced.

Further, when a flaw caused by the transfer of coins on a glass surface for capturing an image occurs, noise due to the flaw is superimposed on the image signal. In addition, there has been a problem that a transfer device such as a belt or a rubber roller is reflected on the imaging surface.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and reduces image blur of a recognition object such as a coin transferred in a predetermined direction, and reduces the image blur in the vertical and horizontal directions. An object of the present invention is to reduce the error with respect to the reference image by averaging and improve the reliability of coin discrimination. It is another object of the present invention to reduce these noise images and average them in the vertical and horizontal directions of the image by reducing the scratches on the traveling path and the reflection of the transfer device such as a roller.

[0009]

In order to solve the object, the invention according to claim 1 irradiates an inspection light to a recognition object transported in a predetermined direction, and irradiates the inspection light with the inspection light. The reflected light from the object to be recognized is picked up by a CCD sensor, and the brightness of the image signal for one frame picked up by the CCD sensor is projected for each column or row, and the brightness for each column or row is calculated. In the recognition object edge detection device configured to detect the edge position of the recognition object from the projection result, the arrangement direction of each pixel and the arrangement direction of each row of each pixel constituting the imaging surface of the CCD sensor are as described above. It is characterized in that it is provided to be inclined with respect to the transfer direction of the recognition target.

According to a second aspect of the present invention, each of the pixels has a quadrangular shape, and a diagonal direction of the quadrangle substantially coincides with a moving direction of the recognition target.

According to a third aspect of the present invention, the arrangement direction of each pixel constituting the imaging surface of the CCD sensor in each column and each row is set to about 45 degrees with respect to the transport direction of the recognition object. It is characterized by becoming.

According to a fourth aspect of the present invention, the arrangement direction of each pixel constituting the imaging surface of the CCD sensor for each column and each row is different from the transfer direction of the object to be recognized. The frame is set so as to substantially coincide with a diagonal direction of a frame screen for forming an image signal for the frame.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a case where the edge detecting device for an object to be recognized according to the present invention is applied to a coin recognizing device will be described with reference to an embodiment shown in the drawings.

The circuit configuration of the present invention is the same as that shown in FIG. This circuit configuration includes a scanner unit 1, a control unit 10, and a monitor 12. As shown in FIGS. 2 and 7, the scanner unit 1 irradiates a coin 2 which is a circular object with light from a light source 25 toward an edge portion of the coin 2 through a lens 3. In this irradiation, the coin 2 is irradiated with the dark field light 4 at a shallow angle, and the obtained reflected light 5 is sent to the CCD unit 7 through the optical system 6. The CCD unit 7 includes a CCD sensor 23 including a CCD (charge coupled device) as shown in FIG. FIG. 8 shows an imaging surface of the CCD sensor 23.
The CCD 23 is a pixel 30 in which a large number of n rows × m columns of square light receiving units constituting an imaging surface are two-dimensionally arranged.
Is formed from.

The two-dimensionally arranged pixels 30
In contrast to this, scanning is performed in the horizontal and vertical directions as usual, and photoelectric conversion is performed in which successive charge transfer is performed to extract an analog image signal corresponding to input light. The analog image signal that has been photoelectrically converted is amplified by the amplifier 8, and the amplified image signal is converted to a digital signal via the A / D converter 9 to become an output signal. The digital signal is fetched into the frame memory 11 only for a part necessary for recognition, and the control unit 10 performs a series of image processing for feature extraction to perform identification determination.

In the circuit shown in FIG. 7, based on the reflected light received from the circular object 2 such as a coin, an edge point in each direction is obtained in the frame memory 11 by horizontal and vertical luminance projection. The coordinates are calculated. In the luminance projection, histograms are obtained by adding the luminances of all pixels in one row (horizontal direction) or one column (vertical direction) on a two-dimensional square matrix (n × m). From this histogram, a horizontal luminance projection and a vertical luminance projection are obtained. Next, for each luminance projection, scanning and detection are performed using horizontal and vertical scanning lines. Then, a reference point where each scanning line exceeds the threshold value of the luminance projection is selected, and an intersection point where each scanning line in the horizontal and vertical directions intersects with each distribution line of the luminance projection is detected, and an edge point in each direction is detected. Seeking.

In the above configuration, the embodiment according to the present invention, as shown in FIG. 1, transfers the coin 2 when the coin 2 is transferred onto the surface of the glass 24 by a belt or rubber roller (not shown). The angle D with respect to the center line R of the CCD sensor 23 with respect to the direction F is set to 45 degrees. That is,
The CCD sensor 23 is arranged to be inclined with respect to the transfer direction F of the coin 2. 26 indicates a case.

Next, the operation of the recognition object edge detecting apparatus according to the present invention will be described with reference to FIGS. FIG. 3 shows an intentionally enlarged state in which the image blur has occurred when the coin 2 is transferred in the transfer direction F. Further, a case is shown in which the coin 2 causes image blurring from the position 2A parallel to the transfer direction F from the position 2A due to unevenness of the conveying speed or the like due to emission of strobe light.
In FIGS. 3 and 4, reference numeral 23A denotes a CCD of the present invention.
The setting position of the sensor 23 is shown, and reference numeral 24 denotes glass provided on the upper surface of the case 26. In contrast, FIG.
As shown in the figure, when the angle of the center line of the CCD sensor 23 is arranged in parallel to the transport direction F, it indicates a normal position where the CCD sensor 23 does not tilt.

FIG. 4 is an enlarged view of the comparison between the normal position where the CCD sensor 23 does not tilt and the set position according to the present invention in the case where the coin 2 has image blurring in the transfer direction F. Is shown. In FIG. 4, it is assumed that the flash photography is performed when the coin 2 reaches the position 2A of the center position C1. At this time, the coin 2 reaches the position 2B of the center position C2 due to image blur. At this time, the image blur occurs on the coin 2 over the area B in the range indicated by the diagonal lines in FIG. Image blur area B is CCD
When the sensor 23 is at the position of the embodiment according to the present invention, it is recognized with respect to a coordinate system inclined by 45 degrees composed of the P axis and the Q axis as shown by the solid line in FIG.

When the coordinate system is inclined at 45 degrees as described above, when the luminance of the image signal of one frame captured by the CCD 23 is projected for each column (vertical direction), the Q region of the image blur is Q11 to Q11. A range Q1 of Q12 and a range Q2 of Q21 to Q22 are formed. When the projection processing is performed for each row (horizontal direction), the P area of the image blur formed on the P axis is P
There is a range P1 of 11 to P12 and a range P2 of P21 to P22. On the other hand, when the CCD sensor 23 is installed at a normal position 32 that is parallel to the transfer direction F and does not tilt, the projection processing is performed on the X axis and the Y axis as indicated by a two-dot chain line. In this coordinate system, when the luminance of the image signal for one frame is projected for each row (horizontal direction), the Y region of the image blur with respect to the Y axis is in the range Y1 to Y12 and Y21 to Y12.
A range Y2 of Y22 is formed. When the projection processing is performed for each column (vertical direction), the X area of the image formed on the X axis becomes
X1 and X2 do not cause image blurring in principle.

As will be apparent from the above description, the areas P1 and P2 of the image blur formed on the P axis correspond to the areas P1 and Y2 of the image blur formed on the Y axis. <Y1, P2 <Y2, resulting in a reduced area. This means that, in the edge detection device for the object to be recognized according to the present invention, when the coin 2 is imaged and image blur occurs in a direction parallel to the coin transfer direction F, C
This indicates that the vertical image blur on the screen of the CD sensor 23 is reduced. In order to identify coins, etc.,
First, the size of the coin must be accurately identified. This is because, if the size is erroneously identified, an attempt is made to identify coins having the wrong size as a reference. For this purpose, it is necessary to minimize the range of the blur of the coin to be identified.

On the other hand, the areas of the image blur Q1 and Q2 formed on the Q axis are larger than the respective areas of the image blur X1 and X2 formed on the X axis where no image blur occurs. The value is small compared to the values of Y1 and Y2 of the image blur formed on the axis, and the possibility of erroneous recognition is very small compared to the erroneous recognition by Y1 and Y2. As a result, the image blur is averaged in the vertical and horizontal directions on the CCD screen. Therefore, the error due to image blurring when the coin 2 is imaged is reduced, and the reliability of coin discrimination, such as obtaining the size and center position of the coin, is improved.

FIGS. 5 and 6 show the CCD sensor 2 of the flaw 12 generated on the surface of the glass 24 as the coin 2 is transported.
3 shows a reflection state. That is, when the luminance of the image signal for one frame is projected for each column (vertical direction) in a coordinate system inclined at 45 degrees in the same manner as described above, the Q area of the pick-scratch image becomes Q1 and one row (horizontal direction). When the projection processing is performed for each image, the P area of the pick-up image becomes P1. On the other hand, when the CCD sensor 23 is set at the normal position 32 where the CCD sensor 23 does not tilt, the X-axis and the Y-axis are formed, and X1 is formed in the X region of the image and Y1 is formed in the Y region. Therefore, the area P1 of the flaw image according to the present invention is reduced as P1 <Y1 as compared with the conventional case where the area 32 is not inclined.

On the other hand, the scratch area Q1 increases as compared with the normal position 32 which is not inclined, but can be reduced to a smaller value as compared with the area Y1. Further, even if a transfer device such as a belt or a roller appears on the imaging surface, the vertical direction of the image is reduced. In this manner, the reflection of the transporting device such as a flaw on the traveling path and the roller is reduced, and is averaged in the vertical and horizontal directions on the CCD screen. Therefore, the effects of reduction and averaging can be obtained for these noise images.

As described above, the embodiment according to the present invention has been specifically described. However, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist thereof. . For example, in the above-described embodiment, the arrangement of the CCD sensor 23 is set to 45 degrees with respect to the transport direction F of the coin 2, but the arrangement is not limited to 45 degrees, and as shown in FIG.
The diagonal direction of 0 may be set so as to substantially coincide with the transport direction F. In this case, it is preferable that the image is aligned in the diagonal direction with reference to the screen for one frame on which the image is processed. Such a setting is particularly effective when specially setting and recognizing an image of a certain portion on the CCD screen. Further, the angle may be set to an arbitrary angle as long as the coin 2 is provided to be inclined with respect to the transfer direction F of the coin 2. When the traveling direction is determined using the area sensor, the recognition target object is not limited to a circle, but may be a square.

[0025]

As described above, in the recognition object edge detecting apparatus according to the present invention, the arrangement direction and row (vertical direction) of each pixel constituting the imaging surface of the CCD sensor are provided. The arrangement direction (lateral direction) is inclined with respect to the transfer direction of the recognition target object. Thereby, the image blur of the recognition target object such as a coin transferred in a predetermined direction is reduced, and the error from the reference image is reduced by averaging the image blur in the vertical and horizontal directions.
The reliability of coin discrimination can be improved. further,
By reducing the pick-up scratches on the traveling path and the reflection of the transfer device such as rollers, there is an effect that these noise images are reduced and averaged in the vertical and horizontal directions of the images.

In addition, since the direction of the target line on the recognition screen is substantially the same as the moving direction of the recognition target, photoelectric conversion can be performed efficiently. Further, since the arrangement direction of each pixel in the column (vertical direction) and the arrangement direction in each row (horizontal direction) are set to about 45 degrees with respect to the transfer direction of the recognition target, the aspect ratio of the CCD screen is reduced. Regardless, it can be easily arranged.

[Brief description of the drawings]

FIG. 1 is a plan view showing a relation between a recognition target object edge detection apparatus according to the present invention;

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram when a coin according to the present invention is transferred in a transfer direction F and image blur occurs.

FIG. 4 is an explanatory diagram in which a normal position where the CCD sensor does not tilt and a set position according to the present invention are compared with each other in an image area when an image blur occurs.

FIG. 5 is an explanatory diagram of a flaw image according to the present invention.

FIG. 6 is an explanatory diagram showing a relationship of a flaw image according to the present invention.

FIG. 7 is a circuit configuration diagram according to an embodiment of the present invention or a conventional edge detection device.

FIG. 8 is an explanatory diagram of a pixel of the CCD sensor according to the present invention.

FIG. 9 is a plan view of a conventional edge detection device for a recognition target.

FIG. 10 is an explanatory diagram of pixels of a conventional CCD sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scanner part 2 Coin 7 CCD part 12 Scratch 23,33 CCD sensor 24 Glass 25 Light source 26 Case 30,34 pixels

Claims (4)

[Claims] An inspection light is irradiated onto a recognition target transferred in a predetermined direction, and reflected light of the irradiated inspection light from the recognition target is imaged by a CCD sensor. The edge of the recognition target object is obtained by projecting the luminance of the image signal for each frame for each column or each row, and detecting the edge position of the recognition target from the luminance projection result for each column or each row. In the detection device, the above C
2. The arrangement direction of each column and each row of pixels constituting an imaging surface of a CD sensor are inclined with respect to the transport direction of the recognition target.
An edge detection device for the recognition target described in the description. 2. Each of the pixels has a square shape,
2. The apparatus according to claim 1, wherein a diagonal direction of the rectangle substantially coincides with a moving direction of the recognition target. 3. The method according to claim 1, wherein the arrangement direction of each pixel constituting the imaging surface of the CCD sensor in each column and each row is set to about 45 degrees with respect to the transfer direction of the recognition target. 2. The apparatus for detecting an edge of a recognition target according to claim 1, wherein: 4. An arrangement direction of each pixel and an arrangement direction of each row of each pixel constituting an imaging surface of the CCD sensor are as follows:
2. A recognition object according to claim 1, wherein said recognition object is set so as to substantially coincide with a diagonal direction of a frame screen for forming an image signal for said frame with respect to a transfer direction of said recognition object. Edge detection device.