JP3147344B2 - Printed character inspection apparatus and printed character inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed character inspection apparatus for inspecting the quality of characters printed on an object, based on image information obtained by imaging the object conveyed at high speed.
And a printed character inspection method .

[0002]

2. Description of the Related Art A printed character inspection apparatus is used, for example, in a factory for inspecting the quality of characters such as the date of manufacture printed on the bottom of a beer can. In a conventional printed character inspection apparatus, a sensor detects that a transported object has reached an imaging position, emits a strobe light at a timing at which a detection signal from the sensor is captured, and captures an image of the object using a CCD camera. After the image signal output from the CCD camera is processed by the image processing device, the image signal is compared with a preset appropriate image to determine whether characters such as the date of manufacture are correctly printed. I have.

[0003]

In particular, when the object is conveyed at a high speed, the object is moved to a predetermined image pickup position between the time when the object is detected by the sensor and the time when the strobe light is emitted. Is transported far away from
The position of the printed character is shifted within the field of view of the CCD camera. In such a case, in the conventional printed character inspection apparatus, even if each printed character is normal, it is determined to be defective simply because the position of the printed character is shifted, and therefore, the quality of the character printed on the target object is deteriorated. There was a problem that it was not possible to properly inspect whether or not the device was normal.

The present invention has been made based on the above circumstances, and has as its object to provide a printed character inspection apparatus capable of properly inspecting the quality of a printed character even when the position of the printed character is shifted. Things.

[0005]

According to the present invention, there is provided a printed character inspecting apparatus for achieving the above object, comprising: , The area of the print character included in the plurality of cutout ranges (i = 1, 2, 3,...), And the ratio νi of each area value Si to the total value S of the plurality of area values Si (=
Si / S), coordinate determining means for determining the coordinates of each real area cut out based on image information of characters actually printed, and A cutout range determining unit that determines a range having the same size as the size of the cutout range serving as a reference stored in the reference data storage unit as an actual cutout range,
The character area calculating means for calculating the character area Si 'within the actual clipping range determined by the clipping range determining means, and the sum S' of the character areas within the plurality of actual clipping ranges calculated by the character area calculating means And a total value S ′ calculated by the area total value calculating means.
And setting the character area allowable range for each cut-out range based on the ratio νi and comparing the character area allowable range with the character area Si ′ to determine whether the quality of the printed character is good or bad. It is assumed that.

[0006] A printed character inspection apparatus according to the present invention comprises:
Storage means for storing standard data, character string circumscribed rectangle setting means for setting a circumscribed rectangle of a print character string, and character circumscribed rectangle setting means for setting a circumscribed rectangle for each character in the circumscribed rectangle of the print character string A position calculating means for calculating the position of each of the circumscribed rectangles, and a range having the same size as a reference cutout range stored in the storage means at the calculated position is determined as an actual cutout range. A cut-out range determining unit, an area calculating unit that calculates an area of a character in each of the cut-out ranges, and a reference stored in the storage unit with respect to an area of a reference character string stored in the storage unit. An area ratio calculating unit that calculates an area ratio of each character; and a character determining unit that determines whether a character is good or not based on whether an area value of a printed character is within an allowable range. The allowable range is characterized in that changes in accordance with the ratio calculated by the area ratio calculating means.

[0007] Further, the printed character inspection method according to the present invention comprises:
The size of a plurality of cutout ranges serving as references based on characters that have been properly printed in advance, and the areas Si (i = 1, 2, 3,...) Of the print characters included in the plurality of cutout ranges serving as the reference
.), The ratio νi (= Si / S) of each area value Si to the total value S of the plurality of area values Si is stored, and the coordinates of each real area cut out based on image information of characters actually printed Is determined for the determined coordinates, a range having the same size as the size of the stored reference cutout range is determined as the actual cutout range, and the character area Si ′ within the determined actual cutout range is determined. Is calculated, and a total S ′ of the calculated character areas within the plurality of actual cutout ranges is calculated,
Based on the calculated total value S ′ and the ratio νi, a character area allowable range for each cut-out range is set, and the character area allowable range is compared with the character area Si ′ to obtain a print character quality. Is judged to be good or bad.

[0008] Further, the printed character inspection method according to the present invention comprises:
The standard data including the area of the reference character string and the data of the area of each character serving as the reference are stored, the circumscribed rectangle of the print character string is set, and the circumscribed rectangle of each character in the circumscribed rectangle of the print character string is set. Setting, calculating the position of each of the circumscribed rectangles, and, with the calculated position as the center, determining a range having the same size as the stored reference cutout range as an actual cutout range, and determining the determined range. Calculate the area of the character within each cut-out range, calculate the area ratio of each stored character as a reference to the area of the stored reference character string, and set the area value of the printed character within the allowable range. Whether the character is good or bad is determined based on whether the character is present or not, and the allowable range changes according to the calculated ratio.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present invention depending on the configuration of the actual cut-out range, not only the cut-out range of the predetermined reference, Ru is determined in consideration of the actual printed character. Ma
Also, for each actual cut-out range, the statements included within that range
Character area, and calculate the
If the sum falls within the total area tolerance, ie
If the overall print density is within the acceptable range,
By comparing the character area the character area and the reference of the cut-out area, it determines the quality of the quality of the printed characters. Even if the print character is shifted from the predetermined position, the quality of the print character can be properly determined by shifting the actual cutout range by the shift amount. In the present invention, characters include symbols and figures.

[0010]

[0011]

[0012]

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a printed character inspection device according to an embodiment of the present invention, FIG. 2 is a schematic block diagram of a main part of an image processing device in the printed character inspection device, and FIG. FIG. 4 is a timing chart for explaining the control at the time, FIG. 4 is a view for explaining a feature amount for binary image information in the printed character inspection apparatus,
FIG. 5 is a flowchart for explaining an operation of inspecting a print character in the print character inspection apparatus, and FIGS.
FIG. 4 is a diagram for explaining a method of setting an actual cut-out range of a print character in the print character inspection apparatus.

The printed character inspection apparatus shown in FIG.
, A strobe light source 4, a strobe drive unit 6, a CCD camera 8, and a conveying means 1 such as a conveyor for conveying the object X.
2 and an image processing device 20. In the present embodiment, the object X is a beer can, the beer can is transported at a high speed (about 1000 / min), and the manufacturing date and the like printed by an ink jet printer in the concave portion at the bottom of the beer can. Consider the case of checking whether characters are printed correctly.

The object 2 to be conveyed is a CCD
It detects that it has approached the camera 8 and has reached the imaging position, and outputs a detection signal. Strobe light source 4
Is a flash light source that irradiates the object X, and the object X is imaged under this illumination. Also, the strobe drive unit 6
The strobe light source 4 emits light at a timing (imaging timing) at which a detection signal from the sensor 2 is taken. Here, the light emission period of the strobe light source 4 is about 1/10000 second.

The CCD camera 8 forms an optical image of the object X as a two-dimensional image on an image pickup device by an image pickup lens, performs photoelectric conversion on the image pickup device, and charges electric charges corresponding to the optical image for a predetermined period. (Charge accumulation period) After accumulation, the accumulated electric charge is output as a one-dimensional electric signal. Although the optical image is constantly formed on the image sensor, the charge corresponding to the optical image of the object X is not effectively accumulated during the transfer of the charge. Then, after the transfer of the charge, the charge is accumulated again in the portion where the charge has disappeared. The one-dimensional electric signal obtained from the imaging device is output to the image processing device 20 as an image signal.

Further, the CCD camera 8 used in this embodiment
Is of the frame accumulation type. That is, in the image sensor, for example, among the pixels of the photosensitive section, first, the charges accumulated in the pixels of the odd-numbered lines are sequentially transferred to the transfer section to obtain the electric signals of the odd-numbered fields. During this time, photoelectric conversion is continued as it is in the pixels on the even-numbered lines. Next, the charges accumulated in the pixels of the even-numbered lines are sequentially transferred to the transfer unit, and electric signals of the even-numbered fields are obtained. Thereafter, the operation of transferring the charges accumulated in the pixels of the odd-numbered lines again and subsequently transferring the charges accumulated in the pixels of the even-numbered lines is repeated. In particular, in the CCD camera 8 of the NTSC standard, the charge accumulation period of one pixel is 1/30 second, and the charge accumulation period of a pixel on an odd line and a pixel on an even line is 1/30 as shown in FIG. 60 seconds off. Further, the first half of the charge accumulation period of the pixels of the odd (even) line includes a charge transfer period for transferring the charges accumulated in the charge accumulation period of the pixel of the previous odd (even) line. This charge transfer period is about 1/1600 second. Therefore, the charge transfer period between the odd line pixels and the even line pixels is also 1/6.
The time is shifted by 0 seconds, and if the pixels of the odd (even) line are transferring the electric charge, the pixels of the even (odd) line always accumulate the electric charge. For example, as shown in FIG. 3, the charge accumulated in the charge accumulation period of the pixels in the odd lines is taken out in the first half of the charge accumulation period of the pixels in the odd lines, and the charge accumulation period of the pixels in the even lines is changed to the pixels in the even lines. In the first half of the charge accumulation period.

The image processing device 20 processes an image signal from the CCD camera 8, and as shown in FIG.
An A / D converter 29 for converting an image signal output from the CCD camera 8 into a digital signal and outputting the digital signal; an image memory 30 for temporarily storing the image signal; and an image of an odd field based on the signal stored in the image memory 30 Output field determining unit 2 for outputting a signal or an image signal of an even field
2, an image processing unit 32, an image determining unit 34, an image processing memory 36, and an image determining memory 38. The output field determination unit 22 includes a timing signal generation unit 24, a field determination unit 26, and a field selection unit 28.

The timing signal generating section 24 generates a timing signal for controlling the operation of each section of the image processing device 20 and the CCD camera 8. As shown in FIG. 3, in the CCD camera 8, the timing at which a high (low) level signal from the timing signal generation unit 24 is fetched is such that the charges accumulated so far in the pixels of the odd (even) lines are transferred and newly added. This is the timing to start accumulating charges. Also, the period of 1/60 seconds during which a high (low) level signal is received from the timing signal generator 24 is represented by C
This is the camera output period in which the odd (even) field image signal is output from the CD camera 8.

When receiving the detection signal from the sensor 2, the field determination unit 26 determines whether the timing signal from the timing signal generation unit 24 is at a high level or a low level, and outputs the determination signal. Is what you do.
Since the CCD camera 8 is synchronized with the image processing device 20 by the timing signal from the timing signal generator 24,
The image signal of the odd field and the image signal of the even field corresponding to the detection signal are those that were captured in the first half of the charge accumulation period of the pixels of the odd line and the pixels of the even line, respectively, or those that were captured in the second half. You know if there is. That is, if the timing signal from the timing signal generator 24 is at a high level when the detection signal is sent from the sensor 2, the image signal of the odd field corresponding to this detection signal is generated during the charge accumulation period of the pixel of the odd line. It is determined that the image was captured in the first half, and that the image signal of the even field was captured in the second half of the charge accumulation period of the pixels in the even line. If the timing signal is at a low level, it is determined that the image signal of the odd field is captured in the latter half of the charge accumulation period of the pixel of the odd line, and the image signal of the even field is determined as the image signal of the pixel of the even line. Is determined to have been taken in the first half of the process.

The field selecting section 28 picks up an image of the odd field image signal and the even field image signal corresponding to a certain detection signal in the latter half of the charge accumulation period based on the judgment signal from the field judgment section 24. The other field is selected. In the present embodiment, since the charge transfer period is included in the first half of the charge accumulation period, the image signal of the field captured in the second half of the charge accumulation period is
Since the imaging timing does not overlap with the charge transfer period, an appropriate image signal can be selected by the field selection unit 28.

The image processing memory 36 stores information for specifying a cut-out range serving as a reference for dividing a character to be printed into a plurality of predetermined portions. That is, the cutout range serving as a reference is the object X
A range of a rectangle for dividing a plurality of characters to be printed into several parts. The information for specifying the cutout range includes the center position of each cutout range, the center position when several cutout ranges are put together, the relative position between some cutout ranges, and the like. The judgment of good or bad of the printed character is made for each cutout range as a unit.

The image processing section 32 includes a field selecting section 28
The predetermined image processing is performed on the appropriate image signal selected in. Specifically, image information is binarized to calculate the number of connected regions, label those regions, and determine the area and circumscribed rectangle of the labeled region (hereinafter also referred to as an island or a label). Then, the actual cutout range is determined, and the feature amount data indicating the area of all the print characters included in each actual cutout range and the circumscribed rectangle is calculated. The calculated feature amount data is output to the image determination unit 34.

In this embodiment, as the feature data, the area value, the X and Y coordinates for specifying the circumscribed rectangle, and the center position of the circumscribed rectangle are used. For example, FIG.
For binary image information having three islands A ₁ , A ₂ , and A ₃ as shown in (a), the area value for island A ₁ is:
It refers to the total number of pixels included in the island A _1. Island A
X and Y coordinates for specifying the circumscribed rectangle ₁ are shown in FIG.
As shown in (b), X · Y coordinates of the vertices of the rectangle circumscribing the island A _1, that is, the maximum value X _EN and the minimum value X of the X coordinate
_S , the maximum value Y _EN and the minimum value Y _S of the Y coordinate.
Then, the center position of the circumscribed rectangle is represented by coordinates (X _N, Y
_N ) = ((X _EN + X _S ) / 2, (Y _EN + Y _S ) / 2).

The image determination memory 38 stores reference feature amount data indicating the areas and circumscribed rectangles of all print characters included in the cut-out range serving as the reference based on characters that have been properly printed in advance. The image determination unit 34 compares the feature amount data of the print characters included in each actual cut-out range output from the image processing unit 32 with the reference feature amount data stored in the image determination memory 38, and Is determined, and the result of the determination is output.

Next, the operation of the printed character inspection apparatus of this embodiment will be described. First, when the beer can approaches the CCD camera 8 and the sensor 2 detects the beer can, the sensor 2 outputs a detection signal to the strobe drive unit 6 and the field determination unit 26.
Output to Now, it is assumed that the strobe drive unit 6 captures a detection signal at, for example, a timing A shown in FIG. At this time, the image of the beer can is captured in the second half of the charge accumulation period in the pixels of the odd-numbered lines, and is captured in the first half of the charge accumulation period in the pixels of the even-numbered lines. Then, after the charges are transferred from the pixels of each line, the image signal of the odd field and the image signal of the even field are respectively output during the camera output period,
Output from the CCD camera 8 during the camera output period.
On the other hand, when receiving the detection signal from the sensor 2, the field determination unit 26 sets the image signal of the odd field in the second half of the charge accumulation period of the pixel of the odd line based on the timing signal from the timing signal generation unit 24. It is determined that an image has been taken. The field selection unit 28 discards the image signal of the even field based on the determination signal from the field determination unit 26 and extracts only the image signal of the odd field.

It is also assumed that the strobe drive unit 6 captures a detection signal at, for example, a timing B shown in FIG. At this time, the image of the beer can is captured in the second half of the charge accumulation period in the pixels of the even-numbered lines, and is captured in the first half of the charge accumulation period in the pixels of the odd-numbered lines. Then, after the charges are transferred from the pixels of each line, the image signal of the even field and the image signal of the odd field are respectively output to the camera output period,
Output from the CCD camera 8 during the camera output period.
On the other hand, when receiving the detection signal from the sensor 2, the field determination unit 26 determines, based on the timing signal from the timing signal generation unit 24, the image signal of the even field in the second half of the charge accumulation period of the pixel of the even line. It is determined that an image has been taken. The field selection unit 28 discards the image signal of the odd field based on the determination signal from the field determination unit 26 and extracts only the image signal of the even field.

Next, the field selection unit 2
The quality of the characters printed on the beer cans is inspected based on the appropriate image signal selected in step 8. In the present embodiment, as shown in FIG. 6, a case is considered in which characters are printed in a two-stage configuration on the bottom of a beer can. In the upper row, the name of the beer maker is printed, and in the lower row, the date of manufacture is printed. Usually, the name of the manufacturer is also printed on the side of the beer can, so that accurate quality inspection is not required for each letter of the manufacturer. Therefore, in the case of the present embodiment, the quality of the character indicating the date of manufacture is particularly strictly inspected. For this reason, in the present embodiment, the entire upper part on which the name of the manufacturer is printed is set as a cut-out range serving as one reference, and the quality of the characters printed as a whole is determined for the manufacturer. In addition, for the lower part where the date of manufacture is printed, a cut-out range is set as a reference for each character, and the quality of the printed character is determined for each character.
The information that specifies the cut-out range that serves as a reference for the characters printed on the upper part and the information that specifies the cut-out range that serves as the reference for the characters that are printed on the lower part are measured based on characters that have been properly printed in advance. And stored in the image processing memory 36.

When the image signal selected by the field selection unit 28 is sent to the image processing unit 32, the image processing unit 32
After binarizing the image signal, the number of regions connected to the binarized image information is calculated, and each region is labeled. Then, for each of the labeled islands, the area value, the XY coordinates specifying the circumscribed rectangle, and the center position of the circumscribed rectangle are obtained.

Next, the image processing unit 32 determines the actual cut-out range of the print character according to the flowchart of FIG. First, as shown in FIG. 6A, the positions of the upper and lower ends and the left and right ends of the entire printed character are obtained (step 1). This means that, of the X and Y coordinates that specify the circumscribed rectangle for each island, the maximum and minimum values of the X coordinate, Y
It can be obtained by finding the maximum and minimum values of the coordinates. Then, to calculate the center position P ₀ of the circumscribed rectangle of the entire printed characters (step 2).

The whole print character is divided into an upper part and a lower part with a straight line passing through the center position P ₀ of the circumscribed rectangle of the entire print character and parallel to the X coordinate axis as a boundary (step).
3). Then, in the same manner as described above, the positions of the upper and lower ends and the left and right ends of the print characters included in the upper part are obtained (step
4), as shown in FIG. 6 (b), calculates the center position P ₁ of the circumscribed quadrangle (step 5). Also, determine the position of the upper and lower ends and left and right ends for printing characters in the lower portion (step 6), as shown in FIG. 7, and calculates the center position P ₂ of the circumscribed quadrangle (step 7).

The center positions P ₁ and P ₂ thus calculated
Then, the actual clipping range is determined based on the information that specifies the reference clipping range stored in the image processing memory 36. That is, for the print characters included in the upper part, as shown in FIG. 8, the actual cut-out range R ₀ ′ is determined based on the center position P ₁ (step 8). Then, for the islands in which the center position of the circumscribed rectangle is included in the cut-out range R ₀ ′, the total area value S ₀ ′ and the XY coordinates specifying the circumscribed rectangle are obtained from the feature data of those islands (step 9). ). Further, as shown in FIG. 8, the actual cut-out ranges R ₁ ′, R ₂ ′ for the six characters of the date of manufacture are determined for the print characters in the lower part, based on the center position P ₂ of the circumscribed rectangle, as shown in FIG. ,..., R ₆ ′ are determined (step 10).
Then, each actual cut-out range R _i ′ (i = 1, 2,...)
For, 6), for the islands in which the center position of the circumscribed rectangle is within the cut-out range R _i ′, the total area value S _i ′ and the XY coordinates specifying the circumscribed rectangle are determined from the feature amount data of those islands. Ask (step 11). For example, as shown in FIG. 7, when the print character “D” included in the lower part is cut out and only a single label is included in the actual cutout range R ₆ ′, the total area value S ₆ 'is the area value of the label. When a plurality of labels are included in the actual cut-out range R ₆ ′, the total area value S ₆ ′ is the sum of the area values of the labels.

Each actual cut-out range R thus obtained
The feature amount data of the print character included in _n ′ (n = 0, 1, 2,..., 6) is output to the image determination unit 34, and the image determination unit 34 determines the quality of the print character according to the following procedure. Is inspected (step 12). In the following, the subscript i is 1 to 6
, And the subscript n takes a value from 0 to 6.

When the quality of a character printed by an ink-jet printer is determined to be good or bad, the character printed on the beer can becomes thicker depending on the temperature of the ink, the speed of the conveying means 12, and the like. , May be thin. For this reason, it is necessary to make an appropriate determination according to the density of the printed characters for each beer can. Considering this fact, in the present embodiment, the image determining memory 38, as previously reference data, the reference feature amount data of printed characters included in the clipping range R _n to be each reference which is measured using a reference sample ( Area value _{Sn (0)} , X specifying the circumscribed rectangle
· Y coordinates), the upper limit value S ₀ of the allowable range for the area value S ₀ of printing characters in the cutout range R ₀ as a reference
^MAX and lower limit value S ₀ ^MIN , total area value S ₍₀₎ = S _{0 (0)} + S
_{1 (0)} +... + S _{6 (0)} to the ratio of each area value S _{i (0)} (ratio data) γ _i = S _{i (0)} / S ₍₀₎ , and a reference cutout range R _i The determination parameters p _i ^MAX and p _i ^MIN for setting the permissible range for the area value S _i of the print character included in.

The image determination section 34 first determines the area value data among the characteristic amount data for each actual cut-out range. First, it is determined whether or not the area value S ₀ ′ of the print character included in the actual cut-out range R ₀ ′ in the upper part satisfies the condition of S ₀ ^MAX ≦ S ₀ ′ ≦ S ₀ ^MIN (1) judge. As described above, by using the absolutely set upper limit value S ₀ ^MAX and lower limit value S ₀ ^MIN , when the area value S ₀ ′ satisfies the expression (1), the print density falls within a predetermined allowable range. It is determined that there is.
As described above, by determining the print density based on the area value of a certain number of characters, a more reliable print density can be obtained as compared with the case where the print density is determined based on the area value of only one character. Judgment becomes possible.

Next, the area value S _i ′ of the printed character included in each actual cut-out range R _i ′ in the lower part is determined. When making this determination, first, the total area value S ′ = S ₀ ′ + S ₁ ′ +... + S ₆ ′ is calculated from the area value S _n ′ of the print character included in each actual cut-out range R _n ′. After the calculation, the reference area value S _iK S _iK = S ′ × γ _i for the print characters included in each actual cut-out range R _i ′ is calculated using the ratio data γ _i stored in the image determination memory 38. I do. This reference area value S _iK becomes a criterion for the area value S _i ′ measured this time. Thus, the corrected reference area value S
By using _iK , it is possible to make an appropriate determination according to the print density. Then, these reference area values S
_iK is multiplied by the determination parameters p _i ^MAX and p _i ^MIN to obtain the area value S of the print character included in each actual cut-out range R _i ′.
Calculate the upper limit value S _iK ^MAX S _iK ^MAX = S _iK × p _i ^MAX and the lower limit value S _ik ^MIN S _iK ^MIN = S _iK × p _i ^MIN of the allowable range for _i ′. Then, the image determination unit 34 calculates the area value S _i ′
Is determined to satisfy the following condition: S _iK ^MIN ≦ S _i ′ ≦ S _iK ^MAX (i = 1, 2,..., 6) (2) If all of the conditions of the expression (2) are satisfied, it is determined that the characters of the date of manufacture are printed well enough to be readable by the consumer. As described above, the character representing the manufacturing date can be strictly examined by determining the character for the manufacturing date for each character.

Next, the image determining unit 34 determines the X and Y coordinates for specifying the circumscribed rectangle of the print character included in each actual cut-out area R _n '. For example, when the determination is made for the letter “D” in the lower part, as shown in FIG. 7, the outer diameter F _X ′ in the X direction and the outer diameter F _Y ′ in the Y direction of the circumscribed rectangle are used for image determination. A comparison is made with reference data F _X and F _Y obtained from information about the X and Y coordinates specifying the circumscribed rectangle stored in the memory 38. This makes it possible to determine whether or not the print character has a predetermined shape, or whether or not the character is missing or protruding.

In this way, the image determination unit 34 determines each feature amount data for the print characters included in each actual cut-out region R _n ′, and when all the results are good, the character printed on the beer can Is determined to be of good quality.

In the printed character inspection apparatus according to the present embodiment, when the image processing unit performs image processing, the center position of the circumscribed rectangle for the entire actually printed character is calculated, and a predetermined position is determined based on the center position. Determining the actual cut-out range of printed characters by correcting the actual cut-out range of printed characters according to the deviation even if the position of the actually printed character is deviated from the predetermined position by determining the actual cut-out range of the printed character Therefore, it is possible to cope with misalignment of printed characters, and therefore, it is possible to accurately inspect the quality of characters printed on a beer can conveyed at high speed.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the invention. In the above embodiment, the case where one cut-out range is set for the characters indicating the manufacturer name in the upper part is described. However, for the character indicating the manufacturer name, one cut-out range is set for each character. May be set.

Further, in the above embodiment, when making a decision on the area value data, one area value data is decided by using a preset upper limit value and lower limit value, and the other area value data is determined by a ratio. The case where determination is made using data has been described. For example, all area value data may be determined using preset upper and lower limits.

Further, in the above-described embodiment, the case where the quality of the print character is determined using both the area value data and the circumscribed rectangle data has been described. May be determined.

[0043]

As described above, according to the present invention, with the above-described configuration, the actual cutout range is not limited to the cutout range serving as a predetermined reference, but also to the characters actually printed. Determined in consideration of each actual cutout range , calculate the character area included in that range, and calculate
The sum of any of the multiple areas
Box, that is, the overall print density is
Character range of each actual cutout range
The quality of the printed character is determined by comparing the product with the reference character area. Therefore, even if the printed character is deviated from a predetermined position, the actual cutout range is deviated by the deviation. Accordingly, it is possible to appropriately determine the quality of the printed character, and therefore, it is possible to provide a printed character inspection apparatus which is particularly suitable for determining the quality of a character printed on an object conveyed at high speed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a printed character inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a main part of an image processing apparatus in the printed character inspection apparatus according to the embodiment.

FIG. 3 is a timing chart for explaining control at the time of imaging in the printed character inspection apparatus of the present embodiment.

FIG. 4 is a diagram for explaining feature amount data for binary image information in the printed character inspection apparatus of the present embodiment.

FIG. 5 is a diagram illustrating an operation of inspecting a print character in the print character inspection apparatus according to the present embodiment.

FIG. 6 is a diagram for explaining a method of setting an actual cut-out range in the printed character inspection apparatus according to the present embodiment.

FIG. 7 is a diagram for explaining a method of setting an actual cutout range in the printed character inspection apparatus according to the present embodiment.

FIG. 8 is a diagram for explaining a method of setting an actual cut-out range in the printed character inspection apparatus of the present embodiment.

[Explanation of symbols]

 Reference Signs List 2 sensor 4 strobe light source 6 strobe drive unit 8 CCD camera 12 transport means 20 image processing device 22 output field determination means 24 timing signal generation unit 26 field determination unit 28 field selection unit 29 A / D converter 30 image memory 32 image processing unit 34 image determination unit 36 image processing memory 38 image determination memory

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-255076 (JP, A) JP-A-51-119782 (JP, A) JP-A-63-15375 (JP, A) JP-A-60-1985 29876 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06T 1/00 G06T ⁷ /00-7/60 H04N 5/225-5/247 H04N 7/18

Claims (8)

(57) [Claims] 1. The size of a plurality of cutout ranges serving as references based on characters that have been properly printed in advance, and the area Si (i =
1, 2, 3,...), Reference data storage means for storing the ratio νi (= Si / S) of each area value Si to the total value S of the plurality of area values Si, Coordinate determining means for determining the coordinates of each real area cut out based on the image information of the character; and, for the determined coordinates, the same as the size of a cutout range serving as a reference stored in the reference data storage means. A cut-out range determining unit that determines a range of sizes as an actual cut-out range; a character area calculating unit that calculates a character area Si ′ within the actual cut-out range determined by the cut-out range determining unit; An area total value calculating means for calculating a total S 'of the calculated character areas in the plurality of actual cut-out ranges, based on the total value S' calculated by the area total value calculating means and the ratio νi Cut out range Set the text area tolerance, the with the character area tolerance character area Si '
A print character inspection apparatus for determining whether the quality of the print character is good or not by comparing 2. The character area allowable range is obtained by multiplying a maximum value determination parameter Pi ^MAX based on a value obtained by multiplying the total value S ′ by the ratio νi, the maximum value of the character area allowable range, minimum value determining parameter Pi ^MIN printing character inspection apparatus according to claim 1, wherein the determining the multiplication value as the minimum value of the character area tolerance. 3. A storage means for storing standard data; a character string circumscribed rectangle setting means for setting a circumscribed rectangle of a print character string; and a character for setting a circumscribed rectangle for each character in the circumscribed rectangle of the print character string. Circumscribed rectangle setting means, position calculating means for calculating the position of each of the circumscribed rectangles, an actual size of the range of the cut-out range serving as a reference stored in the storage means at the calculated position, A cut-out range determining unit that determines a cut-out range; an area calculating unit that calculates an area of a character in each of the cut-out ranges; and a storage unit that stores an area of a reference character string stored in the storage unit in the storage unit. Area ratio calculating means for calculating the area ratio of each character serving as a reference, and a sentence for judging the quality of the character based on whether the area value of the printed character is within an allowable range. And a judging means, wherein the allowable range, the print character inspection apparatus characterized by changes in accordance with the ratio calculated by the area ratio calculating means. 4. The position calculating means calculates a center coordinate of each of the circumscribed rectangles, a center coordinate when a plurality of circumscribed rectangles are put together, or a position of each circumscribed rectangle based on a relative position between the circumscribed rectangles. The printed character inspection apparatus according to claim 3, wherein the calculated value is calculated. 5. The size of a plurality of cutout ranges serving as a reference based on characters that have been properly printed in advance, and the area Si (i =
1, 2, 3,...), The ratio νi (= Si / S) of each area value Si to the total value S of the plurality of area values Si is stored, and based on image information of characters actually printed. Then, the coordinates of each of the real regions cut out are determined, and a range having the same size as the stored reference cut-out range is determined as the real cut-out range with respect to the determined coordinates. A character area Si ′ within the cutout range is calculated, a total S ′ of the calculated character areas within the plurality of actual cutout ranges is calculated, and based on the calculated total value S ′ and the ratio νi A print character inspection method, comprising setting a character area allowable range for each cut-out range, and comparing the character area allowable range with the character area Si ′ to determine quality of a print character. 6. The character area allowable range is obtained by multiplying a maximum value determination parameter Pi ^MAX based on a value obtained by multiplying the total value S ′ by the ratio νi, the maximum value of the character area allowable range, 6. The printed character inspection method according to claim 5, wherein a value multiplied by a minimum value determination parameter Pi ^MIN is determined as a minimum value of the character area allowable range. 7. A method for storing standard data including an area of a reference character string and an area of each character as a reference, setting a circumscribed rectangle of the print character string, and setting characters in the circumscribed rectangle of the print character string. A circumscribed rectangle is set for each, a position of each of the circumscribed rectangles is calculated, and a range having the same size as the stored reference cutout range is determined as an actual cutout range around the calculated position. Calculating the area of the character within each of the determined cutout ranges; calculating the area ratio of each of the stored reference characters with respect to the area of the stored reference character string; A printed character inspection method, wherein the quality of a character is determined based on whether the character is within the range, and the allowable range changes according to the calculated ratio. 8. The position of each of the circumscribed rectangles may be calculated based on center coordinates of each of the circumscribed rectangles, center coordinates when a plurality of circumscribed rectangles are put together, or relative positions between the circumscribed rectangles. The printed character inspection method according to claim 7, characterized in that: