JP3226614B2 - Method and apparatus for binarizing surface state using defocused image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for binarizing a surface condition such as a flat surface.

[0002]

2. Description of the Related Art Blots on a flat plate surface that is spatially smooth and has a large deformation compared to the event to be binarized.
Discolored areas (changes in physical properties of the solid surface) such as dirt, burns, uneven paint, letters, and symbols, holes, dents, grooves, cracks, bumps, ridges, and streaks Judgment of the state (change state of the physical shape of the solid surface), photographed on the surface of a photograph, film, paper, cloth, etc., which is spatially smooth and has large deformation compared to the event to be binarized Judgment of scattered discolored areas, scattered discolored areas printed or painted, patterns projected on the surface, determination of wrinkle state (change of physical properties of solid surface), spatial smoothness and binarization Figure of the discolored area on the liquid surface that has a large deformation compared to the target event (change of the physical properties of the liquid surface), suspended matter, bubbles, ripples (change of the physical shape of the liquid surface) At present, qualitative judgment by human eyes Rely either rely on the process by the dedicated image processing system. Judgment by human eyes requires skill, not everyone can judge easily,
Sometimes the result is not always accurate,
The work efficiency was poor, and it took a considerable amount of time to make the judgment. When using a dedicated image processing system,
There are disadvantages in that complicated hardware and software are required, the system is expensive, and processing takes a lot of time.

Therefore, if the measurement of such a surface condition and the quantitative determination of its size and number can be automated by a simpler method without using a dedicated image processing system,
It is considered that it can greatly contribute to work efficiency, uniform quality and cost reduction.

[0004]

In order to construct a quantitative system for the automatic quantification of the surface condition as described above and the quality of an object having the surface based on the quantification, first, a computer analysis is used. It is possible to do. In order to analyze the state of the surface with a computer, one method may be to scan a photograph of the surface with an image scanner or the like and obtain digital data representing the surface state. The digital data obtained in this way has a large value in a place where the photograph looks bright, and has a small value in a place where the photograph appears dark.

Accordingly, for example, a dark spot, a stain, a hole, a depression, a shadow of a bump-like projection or a streak, etc., have a relatively small value as compared with the surrounding area, and other flat areas having no shadow. It is considered that the value is relatively large in bright places and bright places. In addition, it is considered that the value of a spot that looks brighter than the surrounding area or a bright discolored area that is scattered is relatively larger than the surrounding area, and the value of the other parts is relatively smaller. Therefore, if a certain value is used as a boundary and the pixel is divided into a pixel having a larger value and a pixel having a smaller value, that is, binarization, a stain, a stain, a hole,
It is considered that events to be identified such as dents, protrusions, dotted discolored areas, and the like can be distinguished from other portions.

[0006] However, regarding the surface state of the surface which looks almost homogeneous without the above-mentioned events to be identified, binarized data obtained at such a fixed value is obtained. May be shown. This is because, even on a surface without an event to be identified, due to unevenness of light contact or the color of the material of the target surface, light and dark spots with a large spatial scale compared to the event to be identified, This is because they have been caught by binarization. In this case, even a surface having no events to be identified is erroneously determined to be present.
This is because of the unevenness of light and the color of the material on the surface of the object, the light and dark mottling spatially larger than the event to be identified, and the light and dark mottling due to the event to be identified. This means that it is not possible to make a distinction with binarized data at a fixed value.

In order to avoid such a problem, instead of using a fixed value, binarization may be considered by using the value of each pixel obtained by smoothing digital data over a surface as a boundary value. According to the binarized data with such a surface smoothed value as a boundary, the existence of the event to be identified can be more clearly identified. However,
In such a method, it is necessary to first obtain a two-dimensional smoothing operation using a computing device to obtain a value that has been smoothed two-dimensionally, and it is not always possible to perform simple, inexpensive, speedy, and efficient accurate judgment. I couldn't say it.

An object of the present invention is to provide a method and an apparatus for binarizing a surface state of a flat plate or the like, which can solve the above-mentioned problems of the prior art.

[0009]

According to the present invention, there is provided a method for binarizing a surface state, comprising the steps of: capturing an image of a surface by an imaging means such as a video camera or an image scanner; Then, the surface is defocused to obtain a defocused image and photographed by an imaging means such as a video camera or an image scanner, and second digital data representing a defocused image of the surface is generated. The binary data is created by calculating the difference between the first digital data and the second digital data every time and assigning one or the other of the two-level values according to the positive or negative of the calculation result. It is characterized by doing. When calculating the difference between the first digital data and the second digital data and creating binary data according to the positive or negative of the calculation result, the event to be identified that is to be extracted is In some cases, a simple calculation, such as adding a constant or variable bias value to the calculation result, is performed for the purpose of selecting.

The apparatus for binarizing a surface state according to the present invention is a video camera means for generating a first video signal representing a focused image of a surface and a second video signal representing a defocused image of the surface. And memory means for converting the first video signal and the second video signal from the video camera means into digital data and storing them as first digital data and second digital data, respectively, and the memory By calculating the difference between the first digital data and the second digital data stored in the means for each pixel and assigning one or the other of the two levels according to the sign of the calculation result. 2
Calculating means for generating the quantified data.

Furthermore, another apparatus for binarizing a surface state according to the present invention generates first digital data representing a focus image of a surface and second digital data representing a defocus image of the surface. Image scanner means and their first digital data and second
Memory means for storing the digital data, and calculating the difference between the first digital data and the second digital data stored in the memory means for each pixel, and calculating the difference according to the sign of the calculation result. A calculating means for generating binarized data by assigning one or the other of the level values.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 schematically shows an example of the configuration of an apparatus for implementing a method for binarizing a surface state according to the present invention. FIG.
As shown in FIG. 2, a light 2 for illuminating a flat plate 1 whose surface condition is to be determined, and two video cameras 3 arranged adjacent to each other so as to photograph the surface of the flat plate 1 illuminated by the light 2, 4, frame memory boards 5 and 6 for converting video image signals from the video cameras 3 and 4 into digital signals for each frame and storing the digital signals, and digital data from the frame memory boards 5 and 6 are taken in. The personal computer 7 includes a personal computer 7 for performing binarization and counting by performing calculations, and a display 8 for displaying a result output from the personal computer 7.

The flat plate 1 may be one of metal plates which are fed one after another on a conveyor in a metal plate manufacturing line such as an iron plate, a copper plate, an aluminum plate or the like, or may be a veneer plate, a laminated wood plate or the like. One of a wooden board, a concrete surface, one of wall surfaces of an architectural structure or a civil engineering structure such as plaster, or one of photographs taken of a paper surface, an object, or a phenomenon in a paper manufacturing line may be used. The frame memory boards 5 and 6 used in such a device are, for example, Canopus Electronics
Super CVI or a device having a function equivalent to or better than Super CVI is suitable. The personal computer 7 includes a display 8 and a hard disk.
CPC9801DA or a device having functions equivalent to or more than CPC9801DA is suitable.

Next, a procedure for obtaining binarized data representing the surface condition of the flat plate 1 using such an apparatus, that is, a quantification procedure, will be described with reference to the flowchart of FIG.

First, when this apparatus is used, as shown in step 10 of the flowchart of FIG. 2, the power is turned on, and the video cameras 3 and 4, the light 2, and the personal computer 7 are always turned on. Further, as shown in step 11, the program is always in an execution state.

Thus, in this embodiment, if it is desired to identify spots, stains, discolored areas, etc. on the flat plate 1,
If it is desired to illuminate the plate so as to make it evenly bright, and to identify holes, dents, projections, etc., illuminate diagonally from the side to create shadows of the holes, dents, projections, etc. An image is taken by the video cameras 3 and 4. The two video cameras 3 and 4 are installed as close as possible to each other and are oriented so as to photograph the same area on the flat plate 1. The video camera 3 captures a normal image (focused image in focus) of the flat plate surface. The other video camera 4 intentionally shifts the focus or attaches a filter to the lens to photograph an out-of-focus image (defocused image) on the flat plate surface. This is for obtaining data corresponding to data obtained by smoothing the focus image of one video camera 3 in terms of area. In this defocus image, spots, smudges, discolored areas, holes, depressions, and shadows of projections are obtained. For example, an event to be identified cannot be identified by blurring.

At step 12, it is determined whether or not the flat plate 1 is within the field of view of the video cameras 3 and 4 depending on whether or not the flat plate 1 is captured by the video camera. This may be separately performed by a sensor or the like that detects the position of the flat plate. As shown in step 13, for example, the process waits until the flat plate 1 on the conveyor stops. Then step 14
As shown by, the video signals from the respective video cameras 3 and 4 are separately converted into digital data (R, G,
(The value of B) and takes it into the personal computer 7.

Next, the personal computer 7 performs a quantification process in step 15. The quantification process is as follows. That is, a calculation of subtracting the second digital data from the frame memory board 6 from the first digital data from the frame memory board 5 is performed for each pixel, and a constant or variable A simple operation such as adding a bias value is performed, and if the calculation result is negative (negative), 0
Binary data is created such as (dark part), plus (positive) 1 (bright part).

The personal computer 7 recognizes, based on the binarized data thus obtained, each of a dark portion or a bright portion corresponding to an event to be identified on the plate surface, An operation for calculating the area, width, and length in the vertical direction is also performed. Furthermore, the personal computer 7 calculates the total number of dark or bright parts, the area of the dark or bright parts,
The number and the like of each of the width and the length in the vertical direction are obtained, and the properties of the surface of the flat plate are ranked therefrom. The results are displayed on the display 8, output to a file, and a printer is connected if necessary. And control (step 16), such as outputting to the host machine or notifying the host machine or the like by connecting to the host machine or the like.

In the embodiment shown in FIG. 1, two video cameras, one for taking a focus image and the other for taking a defocused image, are used. However, the present invention is not limited to this, and may be implemented by first taking a focus image and storing data, and then taking a defocused image and storing the data with one video camera.

FIG. 3 schematically shows another configuration example of an apparatus for implementing the method for binarizing a surface state according to the present invention. As shown in FIG. 3, the apparatus of this embodiment uses one image scanner 23 instead of a video camera. The image scanner 23 has the reading surface 23A for reading the surface of the flat plate 21 on which the surface state is to be determined, and can output the read image as digital data. The apparatus of this embodiment further includes a flat plate 21 and a reading surface 23 of an image scanner 23 when capturing a defocused image.
A, a transparent plate 22 to be inserted between
A frame memory board 24 for receiving and storing the digital data from the image memory 3;
The personal computer 25 includes a personal computer 25 that performs value conversion, counting, and the like, and a display 26 that displays results output from the personal computer 25.

The flat plate 21 may be a single sheet of paper or the like extracted as a sample from a product in the papermaking process, or a single sheet of a photograph of an object or phenomenon. Frame memory board 24 used in such a device
Is, for example, Digital Arts HyPER-FRAM
E + or a device having a function equal to or more than E + is appropriate. The personal computer 25 includes a display and a hard disk.
9801DA or one having a function equivalent to or more than this is suitable.

Next, a procedure for obtaining binarized data representing the surface state of the flat plate, that is, a quantification procedure, using such an apparatus will be described. First, when using this apparatus, the power is turned on, and the power of the image scanner 23 and the personal computer 25 is always turned on.
Make the program always in the running state.

First, as shown in FIG.
1 is placed in close contact with the reading surface 23A of the image scanner 23 to read a normal image (focused image in focus) on the flat plate surface. The digital data of the focus image thus read is stored in the frame memory board 2
4 and stored there. Next, as shown in FIG. 3B, a transparent plate 22 having a uniform thickness is inserted between the flat plate 21 and the reading surface 23A of the image scanner 23, and between the flat plate 21 and the image scanner 23. An image (defocused image) of the out-of-focus on the surface of the flat plate is read at regular intervals. The digital data of the defocused image thus read is stored in the frame memory board 24.
And stored in a storage area different from the digital data of the focus image. The defocused image read second is data corresponding to data obtained by planarizing the focus image read first.

Next, the personal computer 25
The following quantification processing is performed. That is, the digital data of the focus image and the digital data of the defocus image are taken into the personal computer 25 from the frame memory board 24, and the calculation of subtracting the second digital data from the first digital data is performed for each pixel. Then, if necessary, a simple operation such as adding a constant or variable bias value to the calculation result is performed, and if the calculation result is negative (negative), 0 (dark portion); Binary data is created such as 1 (bright part).

The personal computer 25, based on the binarized data obtained in this manner, selects one of a dark portion or a bright portion corresponding to an event to be identified on the plate surface.
For each of them, the recognition is performed, and an operation for obtaining the area, the width, and the length in the vertical direction is also performed. Further, the personal computer 25 obtains the total number of dark or bright portions, the individual areas of the dark or bright portions, the number of the horizontal and vertical lengths, and the like from the calculation results, and obtains the properties of the flat plate surface from the calculated values. Ranking, display the result on a display, output to a file, connect a printer if necessary, output to a printer, connect to a host machine, etc., and notify the host machine, etc. Such calculations and controls can be performed.

[0028]

According to the present invention, instead of having a computer calculate the planar smoothing of digital data of an image,
By taking in image data corresponding to the area smoothed by another video camera, or another video camera or image scanner, a time-consuming calculation of area smoothing can be omitted. The time can be greatly reduced.

In order not to perform particularly large-scale image processing,
This eliminates the need for a dedicated image processing device and can reduce hardware costs.

The brightness of the surface may be uneven depending on how light is illuminated, and no special facility such as a dark room is required, so that it can be handled in a normal environment in a factory.

Using the method and apparatus of the present invention, the surface of various flat objects can be stained, stained, discolored,
Extraction of holes, dents, protrusions, streaks, wrinkles, patterns, etc., and measurement and counting of their size and number, as well as quantitative determination of their surface properties, can be automated, reducing production costs and improving work efficiency. It can greatly contribute to uniform quality.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration example of an apparatus for implementing a method for binarizing a surface state according to the present invention.

FIG. 2 is a diagram showing a processing flow in the apparatus of FIG. 1;

FIG. 3 is a diagram schematically showing another configuration example of an apparatus for implementing the method for binarizing a surface state according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 flat plate 2 light 3 video camera 4 video camera 5 frame memory board 6 frame memory board 7 personal computer 8 display 21 flat plate 22 transparent plate 23 image scanner 23A reading surface 24 frame memory board 25 personal computer 26 display

Claims (8)

(57) [Claims] 1. A video camera or an image scanner
The first digital data representing a focus image of the surface taken by an imaging means such as a scanner is created, and the surface is
Defocused video to obtain a defocused image
Photographed by imaging means such as a video camera or image scanner
Then, second digital data representing a defocused image of the surface is created, a difference between the first digital data and the second digital data is calculated for each pixel, and 2 is calculated according to the sign of the calculation result. A method for binarizing a surface state, wherein binarized data is created by assigning one or the other of the level values. 2. The surface state is a change in the physical shape of the solid surface, a change in the physical properties of the solid surface, a change in the physical shape of the liquid surface, or a change in the physical properties of the liquid surface. The method of claim 1, wherein 3. A video camera means for generating a first video signal representing a focus image of the surface and a second video signal representing a defocused image of the surface in an apparatus for binarizing a surface condition of a surface. And memory means for converting the first video signal and the second video signal from the video camera means into digital data and storing the digital data as first digital data and second digital data, respectively; By calculating the difference between the first digital data and the second digital data stored in the means for each pixel and assigning one or the other of the two levels according to the sign of the calculation result. An arithmetic unit for generating binarized data. 4. The surface state is a change in the physical shape of the solid surface, a change in the physical properties of the solid surface, a change in the physical shape of the liquid surface, or a change in the physical properties of the liquid surface. The device of claim 3, wherein 5. The video camera means comprises two video cameras arranged adjacent to the surface,
One video camera is accurately focused on the surface and generates a first video signal representing the focus image, and the other video camera is defocused on the surface. 5. The apparatus according to claim 3, wherein a filter for obtaining a similar effect is applied to a lens to generate a second video signal representing said defocused image, and said arithmetic means is a personal computer. 6. The video camera means comprises a single video camera installed facing the surface, the video camera taking two shots of the surface, one of which takes a picture of the surface. Focus exactly on
Generating a first video signal representing the focus image;
In another one of the photographing operations, the surface is defocused with respect to the surface, or a filter for obtaining the same effect is applied to the lens, and a second video signal representing the defocused image is generated. 5. The device according to claim 3, wherein is a personal computer. 7. An apparatus for binarizing a surface state of a surface, wherein the image scanner captures first digital data representing a focused image of the surface and second digital data representing a defocused image of the surface. Means, memory means for storing the first digital data and second digital data, and the first digital data and the second digital data stored in the memory means.
Calculating means for calculating binarized data by calculating a difference from the digital data for each pixel and assigning one or the other of the two-level values according to the sign of the calculation result. And equipment. 8. The surface state may be a change in the physical shape of the solid surface, a change in the physical properties of the solid surface, a change in the physical shape of the liquid surface, or a change in the physical properties of the liquid surface. The device of claim 7, wherein