JPH0623646B2 - Imaging type groundwork treatment surface grade determination device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for performing a grade determination of a coated surface to be treated by an image pickup method, and particularly to a degree of rust removal of the surface to be treated by blasting a steel structure such as a ship. The present invention relates to a device for automatically determining.

[Prior Art] Conventionally, the evaluation of this type of surface-treated surface is performed by the Swedish standard (S
It was carried out by an inspector visually comparing with a standard photograph as a limit sample based on IS). The degree of rust removal is indicated by the symbols Sa3.0, Sa2.5, Sa2.0, Sa1.0 (the higher the number, the better the grade), and the grade specified for the coating system to be coated on top is used. I was judging the pass / fail by comparing them.

However, this visual standard photographic method requires a high degree of skill in the determination, and the variations due to individual differences are large, so that quantitative evaluation cannot be performed.

Therefore, as shown in FIG.
A blast meter is devised in which illumination light is radiated at an incident angle of °, the amount of diffused light reflected from the measurement surface b is measured by the light receiving cell d through the filter c, and the degree of rust removal on the measurement surface b is determined from the measured amount. Has been done. As shown in FIG. 5, this blast meter is composed of a sensor part e having a light source a, a filter c, a light receiving cell d, etc. built therein, and a meter part f electrically connected to the sensor part e. The sensor portion e has a housing shape, and the sensor portion e is brought into close contact with the measurement surface b so that the light from the periphery does not enter the light receiving cell d, and the measurement is performed.

[Problems to be Solved by the Invention] However, a convex portion g as shown in FIG. 6 or 7 and a concave portion h as shown in FIG. 8 are likely to be formed on the surface of the measurement surface b, and foreign matter intervenes. Sometimes. In this case the sixth
As shown in FIG. 8 to FIG. 8, a gap is created between the sensor portion e and the measurement surface b, and ambient light enters from here. As a result, the stability of evaluation of the measurement surface b is lowered, and there is a problem in that accurate grade determination cannot be performed.

Thus, the object of the present invention is to solve the above-mentioned conventional problems,
It is an object of the present invention to provide an imaging type coating surface treatment surface grade determination apparatus capable of automatically determining the grade of a measurement surface with high accuracy even if unevenness exists on the measurement surface.

[Means for Solving the Problems] The present invention is directed to a light source for illuminating the entire surface to be measured, an image pickup device for picking up a fixed measurement area of the surface to be measured, and an illuminance of the surface to be measured captured by the image pickup device. And the control unit that controls the luminous intensity of the light source so that the illuminance is within a predetermined range, and divides the image of the measured surface captured by the imager into a number of pixels, and the brightness of each pixel in multiple stages. Measure and create a histogram of the number of pixels for each level of brightness and obtain a cumulative density curve up to each brightness, while creating and storing a cumulative density curve pattern in advance corresponding to each grade indicating the degree of rust removal. Every time, the grade determination of the rust removal degree of the surface to be measured is performed based on the cumulative density curve pattern and the cumulative density curve obtained from the surface to be measured, and an image analysis unit for outputting the result is provided.

[Operation] With the above configuration, the control unit controls the luminous intensity of the light source, so that the surface to be measured (painted surface treated surface) under various environments
The illuminance of is within a predetermined range. That is, the imaging condition of the imaging device can be kept constant. Further, in determining the grade of the rust removal degree of the surface to be measured, by making a histogram for each pixel obtained by the imager for each brightness step and analyzing it, the roughness of the surface to be measured, that is, the rust removal degree It is possible to obtain a grade indicating. Therefore, a cumulative concentration curve pattern corresponding to each grade indicating the degree of rust removal is created in advance, and grade determination is performed from this pattern and the cumulative concentration curve obtained from the surface to be measured. The results are similar to the observation results obtained by and the reproducibility and stability are excellent.

EXAMPLES Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of an image pickup type coating base treated surface grade determination apparatus according to an embodiment of the present invention. The illumination unit 1 illuminates the surface to be measured 2 and also captures an image, and includes two 100 W halogen lamps 3 and eight 50 W krypton lamps 4 as a light source, a CCD camera 5 as an imager, and a zoom lens 6. ing. A halogen lamp 3 and a krypton lamp 4 are arranged so as to surround the CCD camera 5 and the zoom lens 6, as shown in FIG. 2 which is a front view of the illuminating unit 1 viewed from the measured surface 2 side. An illumination focus control unit 7, a monitor 8 and an image analysis unit 9 are connected to the illumination unit 1. Lighting focus control unit 7
Measures the illuminance of the measured surface 2 from the image of the measured surface 2 captured by the CCD camera 5 and adjusts the voltage supplied to the halogen lamp 3 and the krypton lamp 4 so that the illuminance becomes 900 lux. It is configured so that the luminosity thereof can be controlled and the focus of the zoom lens 6 and the zoom ratio can be adjusted. The monitor 8 displays an image of the measured surface 2 taken by the CCD camera 5. Further, the image analysis unit 9 takes in an image of the surface to be measured 2 taken by the CCD camera 5, divides this image into 512 × 512 pixels each having the same area, and sets the brightness of each pixel to 64 levels from 0 to 63. And the grade of the surface 2 to be measured is determined.

Next, the operation of this embodiment will be described.

First, place the illumination unit 1 at a predetermined distance (600 to 100) from the surface 2 to be measured.
Installed at a distance of about 0 mm), the halogen lamp 3 and the krypton lamp 4 are turned on to illuminate the surface 2 to be measured. Then, while observing the image of the surface to be measured 2 projected on the monitor 8 by the CCD camera 5, the illumination focus control section 7 is operated to focus the zoom lens 6 and the image projected on the monitor 8 is projected. The zoom ratio is adjusted so that the measurement area on the measurement surface 2 of 80 × 50 mm is exactly included. At this time, the illumination focus control unit 7 controls the halogen lamp 3 and the krypton lamp 4 in the illumination unit 1 so that the illuminance on the surface 2 to be measured becomes 900 lux.
The intensity of is controlled.

Next, the image analysis unit 9 takes in the image of the measured surface 2 captured by the CCD camera 5 and divides it into 512 × 512 pixels. Furthermore, the brightness of each pixel is measured in 64 steps from 0 to 63, the horizontal axis is the brightness, the vertical axis is the number of pixels, and each brightness corresponds to the brightness of each step in 64 steps and the number of each pixel. Then, a histogram (not shown) is created. And
The number of pixels having a predetermined brightness or less is counted, the percentage (cumulative density) with respect to the total number of pixels is calculated, and a cumulative density curve is obtained based on this cumulative density.
Depending on which one of the patterns of the cumulative concentration curve corresponding to Sa1.0 to Sa3.0 created in advance is included, a grade determination of which grade is performed is performed, and the result of the cumulative concentration and the grade determination is, for example, an image. It is displayed on the monitor built in the analysis unit 9. This cumulative concentration curve pattern is the same as the calculation of the cumulative concentration curve on the surface to be measured described above by grade blasting the test piece and creating a number of grade determination samples corresponding to Sa1.0 to Sa3.0. The maximum and minimum density range for each grade.
The pattern is formed as shown in the figure, and this is stored in the image analysis unit.

Specific measurement results using this example will be described below. 4 pieces of 150 mm square test piece from 9 mm thick mild steel plate with black skin
Glue blast finishing corresponding to Sa1.0, Sa2.0, Sa2.5, Sa3.0 was performed while cutting out a sheet and comparing it with a standard photograph of Swedish standard, and using the apparatus of this example, the luminance distribution of each test piece Was measured. The measurement result is shown in FIG. The horizontal axis represents 64 levels of brightness, and the vertical axis represents cumulative density up to each brightness. As you can see from Figure 3
The cumulative concentration curves of the test pieces corresponding to Sa1.0 to Sa3.0 grades are separated from each other and do not overlap. Therefore, the grade of the measured surface can be determined by obtaining the cumulative concentration of the measured surface.

In addition, the set illuminance (900
Lux), measurement area (80 x 50 mm), brightness level (64 levels), number of pixels (512 x 512), etc. are merely examples.
It is not limited to this.

Further, if an autofocus mechanism is adopted for the zoom lens 6 of the illumination unit 1, it is not necessary for the illumination focus control unit 7 to perform focusing.

[Effects of the Invention] As described above, according to the present invention, the following excellent effects are exhibited.

(1) The grade of the rust removal degree of the entire surface to be measured can be automatically judged without visual inspection, and the judgment accuracy and reproducibility are improved.

(2) Since the measurement and determination are performed without contacting the surface to be measured, accurate grade determination can be performed if unevenness exists on the surface to be measured as long as it is within the depth of focus of the imaging device.

(3) It is possible to automate each coating including shipbuilding coating.

(4) Data indicating the grade of the surface to be measured can be obtained instantly, and the grade determination result can be stored permanently, unlike the case where the site photograph is stored.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an image pickup type coating surface treatment surface grade determining apparatus according to an embodiment of the present invention, FIG. 2 is a front view of an illumination unit in the embodiment, and FIG. 3 is a graph showing a measurement result according to the embodiment. 4 to 8 are explanatory views showing a conventional example and problems of the conventional example. In the figure, 1 is an illumination unit, 2 is a surface to be measured, 3 is a halogen lamp, 4 is a krypton lamp, 5 is a CCD camera, 6 is a zoom lens, 7 is an illumination focus control unit, 8 is a monitor,
Reference numeral 9 is an image analysis unit.

 ─────────────────────────────────────────────────── ─── Continuation of front page Examiner Yasuko Eto (56) References JP-A-59-180346 (JP, A) JP-A-57-139607 (JP, A)

Claims (1)

[Claims] 1. A light source for illuminating the entire surface to be measured, an image pickup device for picking up an image of the surface to be measured over a fixed measurement area, and measuring the illuminance of the surface to be measured captured by the image pickup device and measuring the illuminance. A control unit for controlling the luminous intensity of the light source so as to be within a predetermined range, and an image of the surface to be measured captured by the image pickup device is divided into a large number of pixels, and the brightness of each pixel is measured in multiple stages. A histogram of the number of pixels with respect to the brightness of the step is created, and a cumulative density curve up to each brightness is obtained. On the other hand, a cumulative density curve pattern corresponding to each grade indicating the degree of rust removal is created and stored in advance. An image capturing system characterized by comprising an image analysis unit for performing grade determination of the degree of rust removal of the surface to be measured from the concentration curve pattern and the cumulative concentration curve obtained from the surface to be measured, and outputting the result. Painted surface treatment surface grade determination device.