JP3099273B2 - Appearance inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an inspection result based on analysis data of an image signal photographing the appearance of a product (inspection object) conveyed by a product line. The present invention relates to a visual inspection device capable of obtaining discrimination data.

2. Description of the Related Art For example, in a manufacturing line of a factory, in order to discriminate a product sequentially transferred by a carry-in conveyor line (hereinafter referred to as a line) by a type or to eliminate defective products, for example, Inspection of each product is performed by using an image of the product.

For example, as shown in FIG. 4, when a product P conveyed on a line 1 is detected by a detector 2 constituted by a photo sensor or the like, a detection signal is supplied to a visual inspection device 3, and the visual inspection device 3 distance d ₁ from the position detector 2 line 1
A control signal is sent to an image sensor 4 and a strobe lighting device 5 by, for example, a CCD camera arranged on the downstream side of the camera, and the product is photographed. In this case, the supply timing of the control signal is set based on the distance d ₁ and the speed v of the line 1, that is, so that the product P detected by the detector 2 can be properly photographed by the image sensor 4. The image sensor 4 and the strobe light 5 are set to operate with a time difference of (d ₁ / v) time after the detection signal of the detector 2 is obtained.

The image data obtained from the image sensor 4 is analyzed by the visual inspection device 3 by the above-described photographing operation. For example, by binarizing image data, the area of the whole or a part of the product is calculated, and the center of gravity is calculated.

And the data obtained by this analysis is
For example, the quality or type of the product to be inspected can be determined by comparing it with a preset reference value.

Since the quality or the type of the product can be determined by such a determination system # ₀ , the determination system # _0
By supplying the data obtained by ₀ to the sorting device 6 provided downstream of the line 1 as a control signal, for example, a defective product P 'can be eliminated from the line 1 as shown in the figure. However, the control signals for the sorting device 6, the products of the discrimination data quality, so the product is matched to be sorted by the sorting apparatus 6, include a time difference due to the distance d ₂ and the line speed v of the installation position provided Is done.

[Problems to be Solved by the Invention] By the way, if one determination system # ₀ determines that only one piece of determination data is obtained from a captured image, it is necessary to perform various types of determination on a certain product. The determination system # ₀ must be provided in a plurality of units, and there is a problem that the whole inspection system is undesirably increased in size.

Further, since a predetermined determination is made only by obtaining one analysis result and comparing the analysis result with a reference value, there is a problem that the possibility of erroneous determination increases in some cases.

As an example, a case where it is desired to discriminate between two types of crowns P ₁ and P ₂ as shown in FIG. Assuming that the crown P ₁ has a letter R of “AB” drawn in white in addition to red (shaded area) and the crown P ₂ has a yellow mark M drawn in red ground (shaded area),
If the crown conveyed on line 1 is photographed in an image frame as indicated by a dashed line, and a red area is calculated from the image data by performing binarization processing on the red portion, Since a difference between the crowns P ₁ and P ₂ can be generated, a predetermined reference value is provided. For example, if the area is equal to or less than the reference value, it can be determined as P ₁ , and if the area is equal to or more than the reference value, it can be determined as P ₂ .
However, in this case, the area of the red portion may slightly increase or decrease in each crown due to a manufacturing error, or the portion recognized as red on the image data may fluctuate depending on conditions such as illumination light at the time of shooting, Although it is desired to have a margin as a reference value in consideration of the fluctuation, a rough reference value is not preferable because the reliability of the determination result is also lowered at the same time. In such a case, as a result, variations due to manufacturing errors cannot be absorbed, and erroneous determination occurs.

[Means for Solving the Problems] The present invention has been made in view of such problems, and in a visual inspection device, the color information is independent due to the difference in color information within a color image signal of one screen shot. Area control means for controlling various analysis operations in units of a plurality of different characters or figures recognized as processing units, and analysis data for each area obtained by the control of the area control means. A plurality of unit discrimination data generating means for generating discrimination data by discriminating whether or not a predetermined reference condition is satisfied; and a plurality of discrimination data supplied from each unit discrimination data generating means. And a comprehensive discrimination data generating means for performing a comprehensive decision.

[Operation] Based on the analysis data in various area units, it is possible to generate comprehensive discrimination data relating to the object to be inspected, so that one judgment system can judge a plurality of elements at once. Is possible, and the reliability of the determination result is significantly increased by comprehensively determining each determination.

Embodiment First, an overall configuration of an embodiment of the appearance inspection apparatus of the present invention will be described.

FIG. 1 shows the circuit block, and reference numeral 10 surrounded by a dashed line indicates an appearance inspection apparatus. The appearance inspection device 10 and an image sensor (CCD camera)
4, the illumination device 5, and the detector 2
A judgment system # _{0 as} shown in the figure is configured. In the present embodiment, the illumination device 5 performs the illumination operation as strobe illumination in synchronization with the shutter timing of the image sensor 4, but may irradiate continuous light such as a fluorescent lamp. .

The visual inspection device 10 of the present embodiment in such a determination system # ₀ obtains R, R, obtained by photographing the product conveyed on the line with the image sensor 4 by the product inspection operation described in FIG. The G and B image signals are input as data for product determination.

A / D converters 11R, 11G, and 11B convert the supplied R, G, and B image signals into digital signals, respectively. 12R, 12G, 12
B is a frame memory that stores R, G, and B signals converted into digital signals.

The image data stored in the frame memories 12R, 12G, and 12B is supplied to an image processing unit 14 surrounded by a dotted line via an image bus 13a, and various arithmetic processes are performed.

The image processing unit 14 includes, for example, a binarization processing unit 14a, a center of gravity / inclination calculation unit 14b, a perimeter calculation unit 14c, a density dispersion calculation unit 14d, and the like by a hard logic circuit.
It is designed to analyze image data obtained by photographing a product and calculate data having predetermined contents related to the product.

By extracting a specific color from the image data, the binarization processing unit 14a can calculate, for example, the area of the product (or a specific part of the product). Further, based on the binarized data, each calculation is executed in the center of gravity / inclination calculation unit 14b and the perimeter calculation unit 14c, and the center of gravity, the inclination, the perimeter, and the like of the product are calculated. By dividing the area from the square, the complexity of the outer shape of the product can be obtained.

The density variance calculation unit 14d is configured to calculate the density distribution from the R, G, and B luminance data stored in the frame memory 12.

In addition to these analysis operations, various image processing operations can be performed in the image processing unit 14, and data necessary for the inspection determination to be performed is calculated based on the image data.

Reference numeral 15 denotes a system controller (CPU), and various calculation results obtained in the image processing unit 14 are supplied to the CPU 15 via the control bus 13b, and the CPU 15 sets a predetermined reference value for the calculation results. Then, it is determined whether or not the product satisfies the set conditions.

For example, when it is desired to discriminate only a product of a predetermined size from products sequentially conveyed on a line, an image signal obtained by photographing the entire product is taken into the frame memory 12, and the data is stored in the frame memory 12. The area is calculated by the valuation processing unit 14a. Then, the calculated data is fetched via the control bus 13b, and the value is compared with a preset reference value K (for example, upper and lower reference values (K _H , K _L )). The product is to be identified as a corresponding product. The discrimination result is output as discrimination data to the sorting device 6 shown in FIG. 4 or the like.

The CPU 15 further uses the control function to set the timing based on the detection signal from the detector 2 and output an operation control signal to the image sensor 4 and the illumination device 5.

Reference numerals 15a and 15b denote memory units (ROM and RAM) in the CPU 15, and the above-described reference values for determination are stored in advance along with various control data for each target item and determination content.
Note that input and output of information in the CPU 15 are performed via an interface unit inside the CPU, but the interface unit is omitted from the description.

Reference numeral 16 denotes an operation panel (keyboard) for the user to perform various operations on the CPU 15, and performs operations such as selecting reference values and control contents stored in a memory unit.

Reference numeral 17 denotes an image stored in the frame memory 12 and the CPU 1
5 shows a display for displaying control images (operation menu, image window frame, etc.) supplied from 5. The display of an image or the like may be performed by an external CRT or the like.

Reference numeral 18 denotes a memory card drive, which is an external memory card (for example, a RAM card that performs backup with its own power
(A magnetic recording medium, an optical recording medium, etc.), so that control data stored in a memory card can be input to the CPU 15 or an image signal held in the frame memory 12 can be stored in the memory. Memorize it on the card,
It can be used for external use.

Reference numeral 19 denotes an input / output terminal for inputting / outputting various signals to / from an external device. For example, via the input / output terminal section 19,
A detection signal from the detector 2 for detecting a product conveyed on the line is input and supplied to the CPU 15, and the control signals of various external devices output from the CPU 15 are transmitted to the image sensor 4 and the lighting device as described above. 5, and output to a sorting device (not shown).

The entire appearance inspection apparatus of the present embodiment is configured as described above, and can perform various analyzes based on the image captured by the image sensor 4 to perform various determinations of the target product as described above. It is done as follows.

Further, in the present embodiment, the CPU 15 sets one or a plurality of regions (hereinafter, referred to as windows) in an image signal of one captured image, and performs an analysis operation in the arithmetic processing unit 14 for each window. Control means, and n pieces of unit discrimination data for generating discrimination data in window units by comparing the analysis data for each window obtained by the control of the area control means with a reference value K The generating means and the comprehensive discrimination data generating means for making a comprehensive judgment based on each discrimination data in window units are formed by software means.

For this reason, the image signal photographed by the image sensor 4 and stored in the frame memory 12 is always the first signal.
It is not necessary to calculate the data of the entire image as an analysis target, and it is possible to set up to n windows as a processing unit for the image of one screen and perform analysis and discrimination in window units. More comprehensive discrimination data can be obtained from the discrimination data.

Each of the above means is shown in FIG. 2 as a functional block, and its multiple window processing operation will be described below. Note that functional blocks that are configured in the CPU 15 but are not directly related to this operation are omitted.

In FIG. 2, reference numerals 30 ₍₁₎ to 30 _(n) denote n unit discrimination data generating means, 40 denotes comprehensive discrimination data generating means, and 50 denotes area control means.

The area control means 50 sets a window based on a command input from the operation panel 16 to the CPU 15, and further determines how to perform an analysis process on each set window based on a command from the operation panel 16. Set.
By these settings, the arithmetic processing unit 14 is controlled so that a predetermined analysis operation is performed based on each window.

This control will be specifically described. For example, in the case of determining a crown similar to that in FIG. 5, when the crown conveyed on the line is photographed and an image indicated by a dashed line in the frame memory 12 is obtained. For example, as shown in FIG. 3, an area recognized as containing white and yellow in the image signal with a red background color of W ₁ , an area recognized as containing white as W ₂ ,
Sets a region recognized as including yellow as W _3, to calculate the red area of the land portion of the crown with respect to the image signal in the window W _1, Crown the window W ₂ P ₁
Of by calculating the area of white in correspondence with the part of "AB", with respect to further window W ₃ corresponds to the portion of the mark M crown P _2, and is to be calculated the area of the yellow. .

60 is a reference value setting means, a reference value K ₁ ~K _n corresponding to the processing content of each set window ROM15a or
Each unit discrimination data generation unit 30 reads out from the RAM 15b and
₍₁₎ to 30 _(n) .

When a plurality of windows and processing contents are set under the control of the area control means 50, the analysis data D _{W1 to} D _Wn are respectively output to the unit discrimination data generation means 30 corresponding to each window.
₍₁₎ is input to to 30 _(n), by being compared with a reference value K ₁ ~K _n in each unit determination data generating means, are respectively determined. Then, the discrimination data for each window is output, and predetermined calculation processing such as, for example, a logical product, a logical sum, or a weighted calculation is performed in the total discrimination data generating means 40, and the product as the inspection target is processed. Comprehensive discrimination data is generated.

As described above, by multiplexing and setting a window for one image data and performing each determination, a plurality of items are checked, so that the accuracy of the determination is significantly improved.

For example, in the case of the crown identification in FIG. 3, not only the red area of the ground of each crown but also the area of “AB” (white area) and the area of the mark M (yellow area) are obtained. value
K ₁ below], or [if the white area is the reference value K ₂ or more] or [those satisfying either yellow area is the reference value K ₃ below] in to determine the crown P _1, as a determination reference data Therefore, the influence of manufacturing errors, environmental conditions, and the like can be absorbed. In other words, even if the red area cannot be calculated accurately due to the influence of illumination light and the like, and the red area is incorrectly determined,
As long as accurate judgment is made with other white data or yellow data, the comprehensive discrimination data will be accurate.

Moreover, since it is possible to disperse the weight of each data by determining a plurality of data, each reference value K ₁ ~K _n can also be set with a certain degree margin, further reference value has an allowance Since errors due to product lots and environmental conditions can be absorbed respectively, the accuracy is further increased.

The inspection items for one product include not only the area for each color described above, but also the complexity, inclination, density variance, center of gravity position, etc. of the outer shape of the entire product or a specific part, all of which can be calculated by the arithmetic processing unit 14. It goes without saying that this data can be targeted. Further, when there are a plurality of inspection items for one product and a comprehensive judgment is desired from each inspection item, the determination can be made by one appearance inspection device.

[Effects of the Invention] As described above, the appearance inspection apparatus of the present invention includes different characters or patterns as processing units recognized by the CPU in the color image signal of one screen when the color information is different. An area control means for setting an area, a unit discrimination data generation means, and a total discrimination data generation means are provided so that all properties of characters and graphics of a photographed image can be judged by a single inspection as to whether or not they are good. Therefore, by performing the window processing at the time of performing the inspection, there is an effect that the accuracy of the product determination operation can be significantly improved by a plurality of inspection items.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a visual inspection apparatus according to the present invention, FIG. 2 is a block diagram showing an example of software means formed in a CPU in the present embodiment, and FIG. FIG. 4 is an explanatory diagram of window processing, FIG. 4 is an explanatory diagram of a product inspection system, and FIG. 5 is an explanatory diagram of image processing. 2 is a detector, 4 is an image sensor, 5 is a lighting device, 6 is a sorting device, 10 is a visual inspection device, 12R, 12G, and 12B are frame memories, 14 is an image processing unit, 15 is a CPU, 15a is a ROM, and 15b. Is RAM, 1
9 is an input / output terminal, 30 ₍₁₎ to 30 _(n) are unit discrimination data generation means, 40 is comprehensive discrimination data generation means, 50 is area control means,
Reference numeral 60 denotes a reference value setting means.

(56) References JP-A-62-65179 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06T 1/00 G06T ⁷ /00-7/60 G01N 21 / 88-21/958

Claims (1)

(57) [Claims] An image signal obtained by photographing an object to be inspected conveyed in a product line is analyzed, and it is determined whether or not the analysis data conforms to a preset reference condition. A visual inspection apparatus capable of generating discrimination data relating to an inspection object, wherein a window (W1) indicating a feature point and color information in the window are displayed in a color image signal of one screen obtained by photographing the inspection object. A plurality of different character or graphic regions that are recognized as independent processing units by being different are set based on a command from the operation unit, and the window and the analysis processing content for each region are commanded from the operation unit. Area control means for setting based on the following: the area control for the window of the photographed color image and the color image data for each area A plurality of unit discrimination data generating means for performing discrimination processing set by the means and discriminating whether or not the discrimination with the reference condition is performed, thereby generating discrimination data; and a plurality of unit discrimination data supplied from each of the unit discrimination data generating means. And a control means for outputting comprehensive discrimination data relating to the quality of the object to be inspected based on color image data of each area. A visual inspection device characterized by the following.