JPH0565082B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a surface texture measuring device, and particularly relates to a surface texture measuring device for simultaneously measuring the glossiness and flatness of a painted surface, etc. be.

[Conventional technology]

Conventionally, an apparatus for measuring glossiness, as described in Japanese Patent Publication No. 57-59490, and an apparatus for measuring flatness, as described in Japanese Patent Application Laid-Open No. 56-76004, have been known. These are separate devices, and there has been no idea to measure gloss and flatness at the same time.

[Problem that the invention seeks to solve]

The above conventional technology measures glossiness and flatness separately, which makes the measurement work complicated, and requires accurate reproduction of the position of the detection head to measure glossiness and flatness at the same location. This made it difficult to reduce the size and weight. Therefore, there was also a problem with ease of use in narrow areas.

Glossiness measurements are also affected by flatness. That is, when the flatness is poor, the error in the measured value of glossiness increases. Conventionally, no consideration was given to this point.

An object of the present invention is to provide a small and lightweight surface texture measuring device that can simultaneously measure glossiness and flatness by eliminating the influence of poor flatness on glossiness.

[Means for solving problems]

In order to achieve the above object, the present invention uses a lens system to project and image a pattern having at least one pair of bright and dark areas through a measurement target surface, and to provide a photoelectric conversion element equipped with a pinhole and photoelectrically converting the light intensity of the projected image. a glossiness measurement system that is placed on an image forming plane, moves the pattern so that its brightness crosses the optical axis, and measures the glossiness of the measurement target surface from changes in the projected image of the measurement target surface due to the movement of brightness; A grating pattern with repeated brightness and darkness is projected and imaged through the measurement target surface using a lens system, and an image sensor that photoelectrically converts the light intensity of the grating image is placed on the grating image plane. a flatness measurement system that measures the flatness of a surface to be measured from a reference pitch;
The present invention provides a surface texture measuring device comprising a signal processing system that multiplies the measured glossiness value by a correction magnification depending on the quality of the flatness and outputs the measured flatness value and the corrected measured glossiness value.

[Effect]

In the present invention, the measured value of glossiness is multiplied by a correction magnification depending on the quality of flatness, and the influence of flatness is removed. Obtained by measurement operation.

〔Example〕

Next, an embodiment of the surface texture measuring device according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an optical system within a detection head of a surface texture measuring device according to the present invention. In the figure, 1a and 1b are lamps made of tungsten or halogen, 2a and 2b are diffusion plates such as ground glass that make the light intensity distribution of the light uniform, and 3a and 3b are single lenses that concentrate the diffused and uniform light. Alternatively, it is a condensing lens of a compound lens, which forms two light sources a and b, respectively.

On the light source a side, there is a knife edge pattern 4a that combines a part that transmits all light and a part that does not transmit light at all, a sliding table 4b that serves as a guide when moving this pattern in parallel, and a drive for parallel movement of the pattern. A pattern moving unit 4 is installed to move the knife edge pattern 4a in parallel and reciprocating, consisting of a pulse motor 4c serving as a power source and a ball screw 4d that converts the rotational driving force of the pulse motor 4c into a parallel movement force of the sliding table 4b. be. On the other hand, on the light source b side, a grating pattern 5 is provided in which a portion that transmits all light and a portion that does not transmit light at all are repeated at intervals of about 0.2 mm.

6a and 6b are projection lenses that image the light beams that have passed through the knife edge pattern 4a and the grating pattern 5 through the measurement target surface 11.

Reference numeral 7 designates a pinhole as an aperture that limits the range of light incident on the light source conversion element 8 from the projection lens 6a, and the diameter of the hole is approximately 0.2 mm. 9 is
This is an image sensor that converts the light intensity distribution of an image produced by the projection lens 6b into an electrical signal.

The lamp 1a, the diffuser plate 2a, the condensing lens 3a, the pattern moving unit 4, the projection lens 6a, the pinhole 7, and the photoelectric conversion element 8 are the optical system of the glossiness measuring means. The lens 3b, the grating pattern 5, the projection lens 6b, and the image sensor 9 are an optical system of the flatness measuring means.

Each of these parts 1 to 9 is fixed within the case 10 by a mount (not shown). Although not shown, the case 10 is equipped with a display, a start switch, a pulse motor drive circuit, a protrusion for maintaining a constant distance between the surface to be measured 11 and the case 10, and the like.

FIG. 2 is a block diagram showing a circuit for processing signals obtained from the photoelectric conversion element 8 or the image sensor 9. As shown in FIG. In the figure, 12 is a photoelectric conversion circuit that amplifies the signal of the photoelectric conversion element 8, 13 is an image sensor drive circuit that scans the image sensor 9 and obtains a signal, and 14 is the output of the photoelectric conversion circuit 12 or the image sensor drive circuit 13. 15 is an A/D conversion circuit for converting the selected analog signal into a digital signal; 16 is an A/D conversion circuit for converting the selected analog signal into a digital signal;
17 is a microprocessor (CPU) that processes digital signals, and 17 is a parallel input/output IC for exchanging signals with a start switch and display (not shown) for reading, displaying, etc.
(PIO), 18 is a memory IC (ROM) that stores a program for the CPU 16, and 19 is a memory IC (RAM) that writes and reads the contents and stores the obtained data.

Now, as shown in FIG. 3, the measured value of the glossiness is affected by the quality of the flatness, and if the flatness is poor, only a value lower than the true value can be obtained. Therefore, in the present invention, as shown in FIG.
When measuring, read it out to RAM 19, multiply the measured glossiness by the correction magnification,
It's meant to give you real results.

In the surface texture measuring device configured as described above, when the measurement start switch (not shown) is pressed,
An image of the lattice pattern 5 whose pitch is disordered depending on the degree of flatness of the measurement target surface 11 is captured by the image sensor 9, and sent to the A/D conversion circuit via the image sensor drive circuit 13 and the switch circuit 14. Added to 15. CPU16 is A/D
Based on the digital signal from the conversion circuit 15, the flatness of the surface to be measured 11 is determined from the degree of pitch disturbance of the grating image.

At this time, various definitions can be adopted for flatness. For example, as shown in the above-mentioned Japanese Patent Application Laid-Open No. 56-76004, the standard pitch when there is no distortion is
P ₀ , the measured pitch is P, and the absolute value of the difference between the two |P ₀ -P| is divided by the reference pitch P ₀ , which is the distortion rate δ=|P ₀ -P|/P ₀ is defined as flatness. .

On the other hand, the photoelectric conversion element 8 detects changes in the sharpness of the bright and dark boundaries of the image of the knife edge pattern 4a due to the surface to be measured, and applies the detected changes to the A/D conversion circuit 15 via the photoelectric conversion circuit 12 and the switch circuit 14. Based on the digital signal from the A/D conversion circuit 15, the CPU 16 determines the glossiness of the surface to be measured 11 from changes in sharpness.

Also in this case, various definitions can be adopted for glossiness. For example, as shown in the above-mentioned Japanese Patent Publication No. 57-59490, let the average amplitude of the bright part of the knife edge pattern image be X, the average amplitude of the dark part be Y, and the contrast C=(X-Y)/(X+Y). Defined as glossiness.

As already mentioned, if the flatness of the surface to be measured is quite poor, the measured value of glossiness will be smaller than the true value and the error will increase. To deal with this,
In this embodiment, the correction is made depending on the degree to which the value becomes smaller than the true value. Specifically, when a start switch (not shown) is pressed, the switch circuit 14 is switched in response to a command from the CPU 16, and the CPU 16 sequentially measures the flatness and glossiness, leaving the flatness unchanged and the glossiness unchanged. The measured glossiness is multiplied by a correction magnification corresponding to the flatness and displayed as a measurement result on a display (not shown).

Therefore, it is possible to obtain a surface texture measuring device that measures and displays glossiness and flatness simultaneously, which is completely unaffected by the flatness of a surface to be measured such as a painted surface.

Note that in Figure 1, the optical system for measuring glossiness and the optical system for flatness measurement are shown separated for ease of understanding, but in reality, the light rays cover a surface that is very close to each other on the surface to be measured. Both optical systems are placed close to each other or at a certain angle so that the light rays are irradiated or cross at the same measurement point.

〔Effect of the invention〕

According to the present invention, the measured value of glossiness is multiplied by a correction magnification depending on whether the flatness is good or bad, so even if the flatness is poor, the influence on the glossiness is eliminated, and glossiness and flatness are measured simultaneously. A compact and lightweight surface texture measuring device is obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the configuration of a measuring optical system of an embodiment of a surface texture measuring device according to the present invention, FIG. 2 is a block diagram showing an example of a signal processing circuit of the same measuring device, and FIG. FIG. 4 is a diagram qualitatively showing the degree of error in the glossiness measurement value with respect to the quality of the flatness, and FIG. 4 is a diagram showing the correction magnification for determining the true value of the glossiness from the characteristics shown in FIG. DESCRIPTION OF SYMBOLS 1... Lamp, 2... Diffusion plate, 3... Condensing lens, 4... Pattern moving unit, 4a... Knife edge pattern, 4b... Sliding table, 4c
...Pulse motor, 4d...Ball screw, 5...
Grid pattern, 6... Projection lens, 7... Pinhole, 8... Photoelectric conversion element, 9... Image sensor, 10... Case, 11... Measurement target surface, 12
...Photoelectric conversion circuit, 13 ... Image sensor drive circuit, 14 ... Switch circuit, 15 ... A/D conversion circuit, 16 ... CPU, 17 ... PIO, 18 ...
ROM, 19...RAM.

Claims (1)

[Scope of Claims] 1. A pattern having at least one pair of bright and dark patterns is projected and imaged through a surface to be measured using a lens system, and a photoelectric conversion element having a pinhole and photoelectrically converting the light intensity of the projected image is provided on the image forming surface. a glossiness measurement system that measures the glossiness of a surface to be measured from a change in a projected image of the surface to be measured due to the movement of brightness by moving the pattern so that its brightness crosses the optical axis; A repeated grating pattern is projected and imaged through a surface to be measured using a lens system, an image sensor that photoelectrically converts the light intensity of the grating image is placed on the grating image plane, and the pitch and reference of the grating image from the image sensor are a flatness measurement system that measures the flatness of a surface to be measured from the pitch; A surface texture measuring device consisting of a signal processing system that outputs