JP3054838U - Non-contact type metal surface measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive non-contact metal surface inspection apparatus capable of reliably capturing reflected light of an inspection laser beam with a small imaging device and outputting the state of the reflected light as an electric signal, and being inexpensive. . SOLUTION: A semiconductor laser 1 that projects light toward an article to be inspected B, a light receiving surface 2 of a translucent screen that receives a reflected light R of a laser beam L of the semiconductor laser from the surface of the object, and the same light receiving surface An imaging device 4 that is a CCD camera that captures a received light image and outputs the image as an electric signal; and an image analysis device 5 that uses a computer that inputs the image signal of the imaging device 4 and analyzes the surface state of the article. Consists of

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 INDUSTRIAL APPLICABILITY The present invention is a non-contact metal surface measuring device for inspecting scratches, surface roughness, irregularities, dirt, and the like on the surface of a metal or the like, and is particularly useful for detecting a scratch in a metal forming process.

[0002]

[Prior art]

 Conventional non-contact metal surface measuring devices project light onto the surface of an article, receive the reflected light from the surface with a light receiving element (photocoupler), calculate the reflection angle of the reflected light from the light receiving position, The state of the surface of the article is determined from the reflection angle. However, in this conventional method, if the reflected light spreads greatly depending on the surface condition of the article, the reflected light cannot be captured unless a large light receiving element (photocoupler) is used. ) Was required, and it was expensive.

[0003]

[Problems to be solved by the invention]

 The problem to be solved by the present invention is to solve these conventional problems and to reliably capture the reflected light of the inspection laser light with a small imaging device and output the state of the reflected light as an electric signal. An object of the present invention is to provide a non-contact metal surface inspection device that can be manufactured at low cost.

[0004]

[Means for Solving the Problems]

 The configuration of the present invention that solves the above problems is as follows: 1) a laser that emits light toward the surface of the article, a light receiving surface that receives the laser light of the laser reflected from the surface of the article, and a light receiving image of the light receiving surface. Non-contact type metal surface measuring device consisting of an imaging device that captures an image and outputs an image as an electric signal 2) A semi-transparent screen whose laser is a semiconductor laser and whose light-receiving surface is capable of observing a light-receiving image from behind. Moreover, the non-contact type metal surface measurement device according to the above 1), wherein the imaging device is a CCD camera that captures an image of the rear surface of the screen. 3) The above 1) or 2 wherein an interference filter that transmits only laser light is provided on the front surface of the light receiving surface. 4) The non-contact metal surface measuring apparatus according to any one of 1) to 3) above, wherein the apparatus is provided with a roller that runs along the surface of the article.

[0005]

[Action]

 In the present invention, the light emitted from the laser is reflected on the surface of the article according to the surface condition (scratch, roughness, unevenness, dirt, etc.) and the reflection direction is different. Is received at. If the spread of the reflected light is large, the reflected light can be reliably and inexpensively captured if the light receiving surface is enlarged. The reflected light impinges on the light receiving surface to create a light image corresponding to the surface condition of the article. The image of the light on the light receiving surface is captured by an imaging device, converted into an electric signal, and processed by a computer or the like to analyze the surface state. Alternatively, the image of the imaging device is reproduced on a display, and the operator visually judges the surface condition. If an interference filter is provided in front of the light receiving surface to transmit only light of the wavelength of laser light, sunlight, room light, and other light from other light sources can be blocked, and accurate laser reflection can be achieved. An image of only light can be obtained, and accurate analysis and judgment can be performed. Furthermore, if a roller is attached to the device, it can travel along the surface of the article, and can measure a wide surface of the article.

[0006]

[Embodiment of the invention]

 As the laser of the present invention, a semiconductor laser is preferable because it is small and inexpensive. In addition, since the transmissive screen which can receive the reflected light and observe the received light image from the back surface can perform the image pickup from the back surface, the position of the image pickup device becomes easy. Also, it is preferable to provide a roller in the apparatus because the apparatus can run on the surface of the article and the distance between the semiconductor laser and the surface can be regulated at a constant level. Further, it is preferable to provide an optical filter and an interference filter for transmitting only the laser light in front of the light receiving surface. It is preferable from the viewpoint of quality control of mass production that the image signal of the imaging device be processed by a computer using a software program to analyze the state of the surface so that the automatic inspection can be performed. The distance between the laser beam and the surface of the article depends on the laser and the surface condition of the article to be inspected, but about 10 cm is practical for a semiconductor laser.

[0007]

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the embodiment. FIG. 2 is a side view of the embodiment. FIG. 3 is an explanatory diagram illustrating a measurement state of the example. FIG. 4 is an explanatory diagram illustrating a measurement state in the example. FIG. 5 is an explanatory diagram of the measurement in the example. In the figure, 1 is a red semiconductor laser about 10 cm away from the surface F of the article B, 2 is a light-receiving surface of a screen which is semi-transmissive and a light-receiving point can be observed from the back, and 3 is placed in front of the light-receiving surface 2. An interference filter that allows only red laser light to pass through, 4 is an imaging device of a two-dimensional CCD camera that captures the light image of the light receiving surface 2 from the back, and 5 is a computer that processes and analyzes image signals of the imaging device. An image analysis device, 6 is a device casing, 7 is a traveling roller, and 4 is a support leg. 5a to 5f are components of the image analyzer 5, 5a is a CPU, 5b is a ROM for storing processing program software and substitute data, 5c is a RAM, 5d is a display, and 5e is a keyboard. -5d is an interface. A is a non-contact type metal surface measuring device of the embodiment, B is an article, F is a surface of the article B, D is a scratch on the surface F, G is a light receiving image of the light receiving surface 2, R is a reflected light of a laser beam, and L is a reflected light of a laser beam. This is the laser light of the semiconductor laser 1. In this embodiment, a red laser beam is emitted from the semiconductor laser 1 and reflected on the surface F of the article B, and the reflected light R passes through the interference filter 5 and is received by the light receiving surface 2 having a large area. An image of the light projected on the light receiving surface 2 is picked up by an image pickup device 4 of a rear two-dimensional CCD camera and output to an image analyzer 5 (see FIGS. 1 and 5). If the light-receiving image G of the light-receiving surface 2 is smooth without any damage or dirt on the surface F of the article B, the reflection angle of the reflected light R of the laser light is constant and straight. If the surface F of the article B has flaws, irregularities, or roughness, the direction of the reflected light R changes and the light receiving image G on the light receiving surface 2 changes. For example, FIG. 3 shows an example in which there is a shallow extruded scratch D (see FIGS. 3 (a) and 3 (b)) on the surface F of the article B, and the reflected light R is reflected by the scratch F on the surface F. changes, receiving image G of the light receiving surface 2 is a thin lenticular with a width L ₁ (see Figure 3 (c)). FIG. 4 shows an example in which a deep flaw D (see FIGS. 4 (a) and 4 (b)) of the extrusion process exists on the surface F of the article B. The spread of the reflected light R is large, and the light receiving image of the light receiving surface 2 is obtained. G has a lens shape having a width L ₂ thick as shown in FIG. The apparatus is driven by rollers 7 in a direction orthogonal to the extrusion direction to inspect the entire width of the article. The light-receiving images G of these light-receiving plates 2 are picked up by an image pickup device 4 of a two-dimensional CCD camera placed above the light-receiving surface 2 of the screen and input to the image analysis device 5 as electric signals. From 5, the presence or absence of a flaw and the depth of the flaw are calculated from the state of the received light image. The calculation and analysis are executed by the CPU 5a by the processing program software stored in the ROM 5b, and the following calculation and processing are performed. The arithmetic average roughness (Ra), maximum height (Ry), and ten-point average roughness (Rz) are calculated as the roughness conversion value and the roughness parameter. The correspondence between these values and the actual state of the surface F is determined in advance by experiment or calculation, and is stored in the ROM 5b and collated with the light measurement value to determine the state of the surface. These results are displayed on the remote display 5d, and the data and evaluation of the surface state are output to be used as quality control data. (1) Calculation of roughness conversion value σ The light receiving image of the light receiving plate is converted into gradation data by each pixel of the two-dimensional CCD camera as a luminance value. The total sum of the gradation data of all pixels at this time is S, the gradation data added to each of the vertical columns (n columns) is calculated as A (1... N), and the maximum value is δ1 (vertical ratio ). The value obtained by dividing S by δ1 is defined as δw (horizontal ratio). δ1 = A (1... n) maximum value δw = S / δ1 The ratio between δ1 and δw is calculated as δ. δ is the aspect ratio of the luminance distribution received by the two-dimensional CCD camera, and δ is assumed to be sharpness. δ = δ1 / δw As other operation constants, if the measurement resolution is j and the conversion constant depending on the presence or absence of metal material or surface treatment material is k, the roughness conversion value σ is obtained by multiplying the sharpness by j and k and expressed. σ = δ × j × k (2) Calculation of roughness parameter The arithmetic expressions of the arithmetic average roughness (Ra), maximum height (Ry), and ten-point average roughness (Rz) of typical roughness parameters are as follows. It is obtained from the following items using N σ values calculated within the range of an arbitrary measurement length. N: Number of measurements (sampling value) σp: Largest σ value σv: Smallest σ value σpi: Average value of up to the fifth value from the total average value of σ σvi: Total value of σ Average value of up to the fifth value in ascending order Ra = (1 / N) × Σ (σ) Ry = σp−σv Rz = (1/5) Σ (σpi) + (1/5) Σ (σvi) ,, Can be converted to typical roughness parameters.

[0008]

[Effect of the invention]

 As described above, according to the present invention, the laser light that illuminates the surface state of the article is received once on the light receiving surface, and the image is input by the image pickup device, so that even if the reflected light spreads, it is inexpensive to receive. Since it is possible to cope only by enlarging the surface, it is possible to reliably capture the reflected light and inspect the surface condition. In addition, since a large-sized image pickup device having a wide light receiving range is not required, the device cost can be reduced. If the goods can be run with rollers, the surface condition of wide goods can be inspected. Further, in the case where the interference filter is attached, only the laser beam is received on the light receiving surface, so that the received light image is not blurred or uncertain due to indoor illumination light and sunlight.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is a side view of the embodiment.

FIG. 3 is an explanatory diagram showing a measurement state in the example.

FIG. 4 is an explanatory diagram showing a measurement state in the example.

FIG. 5 is an explanatory diagram of measurement in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Light-receiving surface 3 Interference filter 4 Imaging device 5 Image analysis device 5a CPU 5b ROM 5c RAM 5d Display 5e Keyboard 5f Interface 6 Device casing 7 Roller 8 Missing number 9 Support leg A Non-contact type metal surface measuring device B Article F Surface D Scratched G Received image R Reflected light L Laser light

Claims (4)

[Utility model registration claims] 1. A laser for projecting light toward a surface of an article, a light receiving surface for receiving a reflected light of the laser light of the laser from the article surface, and a light receiving image of the light receiving surface being picked up and an image is formed by an electric signal. A non-contact type metal surface measuring device comprising an image pickup device that outputs an image as an image. 2. A semi-transparent screen in which a laser is a semiconductor laser and a light receiving surface is capable of observing a received image from the back, and an image pickup device captures an image of the back of the screen.
The non-contact type metal surface measuring device according to claim 1, which is a CD camera. 3. The non-contact type metal surface measuring apparatus according to claim 1, wherein an interference filter for transmitting only laser light is provided on a front surface of the light receiving surface. 4. The non-contact type metal surface measuring device according to claim 1, wherein the device is provided with a roller running along the surface of the article.