JP3039211B2 - Painted surface property measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint surface property measuring device for easily measuring the condition of a paint surface of an automobile, for example.

[0002]

2. Description of the Related Art Conventionally, in the production process of automobiles, the condition of a painted surface is strictly inspected, and an example of the inspection of the painted surface is, for example, inspection of sharpness. This inspection of sharpness is a test for examining how flat the painted surface is. When inspecting sharpness, a paint surface property measuring device capable of quantitatively measuring sharpness is used in order to eliminate variations caused by the skill of the inspector and increase the reliability of the inspection result. (See JP-A-63-274847).

The principle of this paint surface property measuring device is to project a stripe pattern as an image to be inspected on the paint surface, observe the disturbance of the reflected image reflected on the paint surface, and inspect the paint surface property. . As shown in FIG. 4, the paint surface property measuring device has an optical system on the light projecting side and an optical system on the light receiving side. The light source 2, the stripe grating 4, and the convex lens 5 connected to the power supply unit 32 are arranged on the light projecting side optical system with reference to the optical axis, and the light receiving lens 7 and the CCD camera 6 constituting the CCD camera 6 are arranged on the light receiving side optical system. The CCD element 9 is disposed with reference to the optical axis. The light source 2 is composed of, for example, a halogen bulb, and the stripe grating 4 is composed of, for example, a glass plate on which a stripe pattern is printed. When the painted surface property measuring device is shipped, the brightness of the halogen bulb serving as the light source 2 is adjusted or confirmed so as to be as specified.

[0004] The light from the light source 2 transmits the stripe pattern through the protective glass 15 and irradiates the painted surface 1, and the light reflected on the painted surface 1 passes through the protective glass 15 and is imaged by the CCD camera 6. It has become so. A measurement image signal related to the reflection stripe pattern captured by the CCD camera 6 is output to an image processing device 30 that digitizes and records the sharpness. This image processing device 30
Is connected to a monitor device 13 for displaying a reflection stripe pattern and a digitized sharpness on a screen, and a warning light 31.

[0005] In the coating surface property measuring apparatus according to the above method,
Since the measured values are quantified based on the contrast (brightness / darkness difference) of the measured reflection stripe pattern image, even if the actual sharpness is the same, the measured value is changed by changing the contrast of the measured image. An error will occur in the digitization of sharpness. For this reason, whether or not the contrast of the measurement image has changed with time due to deterioration of the lamp of the light source 2 or the power supply unit 32, contamination of optical components, and the like after the shipment of the measurement device is determined by measuring a reference plate having a known sharpness. The calibration is performed based on the contrast of the measured image.

FIG. 5 is a flowchart showing a processing flow of the painted surface property measuring apparatus. The processing for measuring a reference plate and the processing for measuring an object to be measured are roughly divided. First,
The stripe pattern is projected on the reference plate, and a reflection image of the stripe pattern from the reference plate is read by the CCD camera 6 (S1). Next, predetermined image processing is performed on the read image of the reflection stripe pattern, and it is determined whether or not the contrast of the measurement image is within a certain allowable range (S).
2). If the contrast of the measured image exceeds the allowable range, a warning is output to the warning light 31 and the monitor device 13 (S3), and the measurement is terminated. Then, appropriate measures such as disassembly adjustment and lamp replacement are performed. On the other hand, when the contrast of the measurement image of the reference plate is within the allowable range, the stripe pattern is projected onto the painted surface 1 to be measured, and the reflection image of the stripe pattern from the painted surface 1 is read by the CCD camera 6 (S4). ), A predetermined image processing is performed on the read image of the reflection stripe pattern, and the sharpness is digitized (S
5) Display the measured value on the monitor device 13 (S6),
Inspect the paint surface properties.

[0007]

In such a conventional paint surface property measuring apparatus, in order to accurately inspect the paint surface property, a calibration for confirming the brightness of the light source 2 using a reference plate is required. Work must be done frequently,
There was a problem that the original measurement work could not be performed quickly.

[0008] Even if the contrast of the image measured on the reference plate is within the allowable range as a result of the calibration, the delicate change in the contrast causes the three textures of smoothness (smoothness, solid feeling). (Gloss feeling) has a drawback that an error occurs in the gloss feeling. On the other hand, if the contrast exceeds the allowable range, accurate measurement values cannot be obtained if the measurement operation is continued, so that it is necessary to perform disassembly adjustment, lamp replacement, and the like. There was a problem that the measurement operation could not be performed quickly.

Further, since the contrast is determined from the image measured by the CCD camera 6, the cause of the contrast exceeding the allowable range is caused by the stripe grating 4, the convex lens 5, the protective glass 15, or the CCD, which is an optical component. It was not possible to judge whether the camera 6 or the like was affected by deterioration, dirt, fogging, or the like, or whether the lamp itself was deteriorated with time.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems associated with the prior art, and can perform quick measurement without the need to check the brightness of the light source. It is an object of the present invention to provide a paint surface property measuring device capable of improving the reliability of measurement by eliminating an error caused by a change in the brightness of the paint.

[0011]

In order to achieve the above object, the present invention provides a method for projecting an image to be inspected on a painted surface by light from a light source, and based on the image to be inspected reflected on the painted surface. In a painted surface texture measuring device for inspecting the properties of the light source, adjusting means for adjusting the brightness of the light source, light source brightness detecting means for measuring the brightness of the light source, based on a signal from the light source brightness detecting means co adjusting the brightness to a predetermined brightness of the light source by actuating the adjusting means Te
The brightness of the light source is predetermined even when the adjusting means is operated.
And a control means for issuing a predetermined warning when the brightness does not reach a predetermined value .

[0012]

The control means activates the adjusting means based on the brightness of the light source measured by the light source brightness detecting means, whereby the brightness of the light source is adjusted to a predetermined brightness. By automatically adjusting the brightness of the light source, it is not necessary to perform a calibration operation for checking the brightness of the light source using the reference plate. Further, since the brightness of the light source is adjusted according to the change in the brightness of the light source, high-precision measurement of sharpness without errors is performed. Moreover, even if the adjusting means is activated
When the brightness of the light source does not reach the
Since the warning is issued, deterioration of the light source can be clearly recognized.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the overall configuration of a painted surface texture measuring device according to the present invention, and FIG. 2 is a structural diagram showing a measuring head of the painted surface texture inspection device, and FIG. FIG. 3B is a front view showing the internal structure, and FIG.

As shown in FIG. 2, the measuring head 25 of the painted surface property measuring apparatus is a small and light handy type measuring head, and has a casing 11 having an opening 12 which serves as a light entrance and exit. In this casing 11,
Light source 2, semi-diffusion plate 3, stripe grating 4, mirror 1 on the light emitting side
0 and a convex lens 5, and a CCD camera 6 on the light receiving side.
Are arranged and housed in order with respect to the optical axis. The light source 2 includes a halogen bulb 2a and a reflecting mirror 2b, and the stripe grating 4 is made of, for example, a glass plate on which a stripe pattern is printed. In this way, the painted pattern 1 is irradiated with the stripe pattern from the light projecting side, and the reflected light is imaged by the CCD camera 6 on the light receiving side. The reflection stripe pattern imaged by the CCD camera 6 is output to an image processing device 30 (corresponding to control means) which digitizes and records the sharpness via an external connector 14. The opening 12 of the casing 11 is sealed with a protective glass 15 serving as a transparent plate, and four free feet 16 are attached to the bottom surface of the casing 11 so as to be extendable and retractable. In particular, in the measuring head 25 of the present embodiment, a brightness detection sensor 33 (corresponding to a light source brightness detecting means) for directly measuring the brightness of the light source 2 is mounted close to the light source 2.

The details of each component of the measuring head 25 having the above-described structure will be sequentially described below.
First, the optical system of the measuring head 25 will be described. The stop 8 is a pinhole stop having a diameter of about 0.2 to 0.3 mm that is stopped down to the diffraction limit of light, and is arranged between the light receiving lens 7 and the CCD element 9 in the same CCD camera 6. This very small aperture 8 blocks all undesired light beams that cause blurring of the image, so that the image can be clearly captured anywhere before and after the focused object plane, and The depth increases dramatically. And, by the dramatic increase in the depth of field due to the aperture 8, the object can be focused no matter where it is, and the stripe grating 4 can be moved without moving the light receiving lens 7 or changing its focal length. It becomes possible to focus on both the painted surfaces 1. As a result, three textures (smoothness, solid feeling, glossiness) of sharpness corresponding to the magnitude of the undulation of the painted surface 1 can be simultaneously and accurately measured. In addition, since the depth of field is significantly increased by the diaphragm 8, the sensitivity can be further improved and the sensitivity can be adjusted, and non-contact measurement can be performed with the measuring head 25 separated from the painted surface 1. . In addition,
If the diameter of the pinhole 8 is made smaller than the diffraction limit, the resolution is lowered due to the diffraction phenomenon, which is not preferable.

Next, the optical system on the light projecting side will be described.
The convex lens 5 included in this optical system is for arranging the stripe grating 4 as far as possible in a pseudo manner in order to increase the sensitivity. By inserting the convex lens 5, the stripe grating 4 is located at infinity. This makes it possible to reduce the size of the device 25 while increasing the sensitivity. Further, as described above, since the depth of field is extremely large due to the aperture 8 and the focus is adjusted anywhere, the stripe grating 4 can be placed at any appropriate position in relation to the convex lens 5, and the position of the stripe grating 4 can be changed. With proper adjustment, it is possible to simulate the stripe grid 4 from the painted surface 1 at a distance of more than infinity, which is invisible to humans. This further improves the sensitivity. Further, in the present embodiment, the mirror 10 is provided to increase the optical path, thereby further reducing the size of the apparatus.

The light source 2 comprises a halogen bulb 2a and a reflecting mirror 2
The light source is disposed a little farther than the focal point b, and forms a condensing light source that spreads after light is once condensed. This is because, since the painted surface 1 is usually a curved surface, the edge of the illuminated surface tends to be darker than the center in a conventional spot-type light source that emits parallel rays. This is to secure more stable brightness on the curved surface. The light distribution angle of this condensing light source 2 is, for example, 40 ° or more,
It is larger than that of the spot type (light distribution angle 0 to 10 °).

The semi-diffusion plate 3 for eliminating light unevenness includes:
Unlike the diffusion plate used conventionally, it diffuses and transmits incident light within a small scattering angle range. For example, frosted glass or focus glass is used. This semi-diffusion plate 3 is
It is placed before the light converging point. Comparing the light transmittance on the optical axis of the diffusion plate and the half-diffusion plate,
% And about 85% for the semi-diffusion plate (both are actually measured values). As described above, unlike the diffusion plate, the semi-diffusion plate has a function of causing light to travel straight to a certain extent, so that the decrease in the amount of light applied to the stripe grating 4 in the optical axis direction can be relatively small. Therefore, by using the semi-diffusion plate 3, it is possible to secure the brightness required for measurement with the light source 2 having a smaller capacity than the conventional one. In addition, as shown in the figure, three half-diffusion plates 3 are used to sufficiently eliminate unevenness. By using an appropriate number of the semi-diffusion plates 3 in this way, it is possible to irradiate the stripe grating 4 with light having no unevenness while securing the light quantity.

The brightness detection sensor 33 is composed of, for example, a photodiode or the like, and is arranged at a predetermined position between the semi-diffusion plate 3 and the light source 2 in order to directly measure the brightness of the light source 2 itself. .

Next, the external structure of the measuring head 25 will be described.
2, the protective glass 15 is attached, and the measuring head 25 itself has a sealed structure. This prevents dust or the like from entering the inside of the measuring head 25, contaminating the optical system and causing a decrease in the performance of the apparatus. At this time, since the measuring head 25 is supported by the free foot 16 at a position away from the painted surface 1, even if part of the light projected through the convex lens 5 is reflected by the protective glass 15, The reflected light does not directly enter the CCD camera 6. Therefore, the opening 12
Can be measured even if is covered with the protective glass 15. In addition, in the case of an apparatus of a type in which the measurement is performed by directly contacting the painted surface 1, although not shown, if the glass is arranged in an inverted V-shape so that the glass surface is perpendicular to the optical axis, the glass is sealed. Since there is no reflection on the glass surface which is not desirable for imaging, the measurement can be performed even when the glass is closed.

Each free foot 16 attached to the bottom surface of the measuring head 25 has a tip which is a swivel-type tip of a ball joint 17 which can be freely rotated, and has a leg built in and capable of adjusting expansion and contraction. A felt is attached to the tip surface of the free foot 16 so as not to damage the painted surface 1 during measurement. The free foot 16 is of a swivel type in which the toes can freely rotate and the legs can be adjusted to expand and contract, so that the direction of the toes and the length of the legs can be appropriately adjusted even if the painted surface 1 is any curved surface. By doing so, the reflected light from the painted surface 1 can be always captured by the CCD camera 6. By providing the feet 16 in this manner, the head 25 can be separated from the painted surface 1 during measurement. However, as described above, the aperture 8 in the CCD camera 6 is very small, about the diffraction limit. The disturbance light is almost blocked by the stop 8 and is not affected by the disturbance light. Therefore, the measurement head 25 can be separated from the painted surface 1 for measurement.

Further, in this embodiment, a timer circuit is incorporated in the operation switch mounting board 20, and if the operation switch is not operated for a certain period of time, the light source 2 and the CCD are automatically turned on.
The power supply to the internal devices such as the camera 6 and the monitor 13 is cut off, and the power is turned on as soon as the operation switch is operated.

As shown in FIG. 1, a measurement image signal relating to the reflection stripe pattern captured by the CCD camera 6 is input to the central processing unit 30a of the image processing device 30. The image processing device 30 is connected to a monitor device 13 for displaying a reflection stripe pattern image, a digitized sharpness or a predetermined warning on a screen, and a warning lamp 31 that lights up to notify a worker of the predetermined warning. Have been.
The signal from the brightness detection sensor 33 is transmitted to the image processing device 30.
Is input to the light source brightness determination unit 30b. The light source brightness determination unit 30b compares the signal from the brightness detection sensor 33 with a preset threshold value to determine whether the brightness of the light source 2 is brighter or darker than normal brightness. . The signal of the determination result in the light source brightness determination unit 30b is input to the central processing unit 30a.

On the other hand, to the power supply section 32 to which the light source 2 is connected, an adjusting section 34 (corresponding to adjusting means) for adjusting the current and voltage output from the power supply section 32 to the light source 2 is connected. . The adjustment unit 34 includes a light source brightness determination unit 3
The power supply unit 32 is operated based on the adjustment signal output from the central processing unit 30a in response to the signal from 0b. For example, if the light source brightness determination unit 30b determines that the brightness of the light source 2 is darker than the normal brightness, the central processing unit 30a sets the current brightness of the light source 2 to the normal brightness. The required increase of the current or the like is calculated, and the calculation result is output to the adjustment unit 34 as an adjustment signal. Then, the adjustment unit 34 performs control to increase the output current or the like of the power supply unit 32 based on the adjustment signal from the central processing unit 30a,
This allows the light source 2 to operate brighter.

As described above, the brightness of the light source 2 is automatically adjusted by adjusting the output current and the like of the power supply unit 32. However, when the brightness of the light source 2 cannot be adjusted to the normal brightness, The central processing unit 30a turns on the warning lamp 31, displays the contents of the warning on the monitor device 13, and notifies the worker of a predetermined warning.

The operation of the apparatus for measuring the properties of a painted surface constructed as described above will be described with reference to the flowchart shown in FIG.

When the measurement of the object to be measured is started, the stripe pattern is projected on the painted surface 1 and the image of the stripe pattern reflected from the painted surface 1 is read by the CCD camera 6 (S10). The brightness of the power supply 2 at this time is measured by the brightness detection sensor 33, and the measured signal is input to the light source brightness determination unit 30b (S11). The light source brightness determination unit 30b compares the signal from the brightness detection sensor 33 with a preset threshold value to determine whether the brightness of the light source 2 is brighter or darker than normal brightness ( S12). In the light source brightness determination unit 30b,
When it is determined that the brightness of the light source 2 at the time of measurement is normal, the image information read by the CCD camera 6 is input to the central processing unit 30a of the image processing device 30, and the central processing unit 3
In step 0a, predetermined image processing is performed on the input image of the reflection stripe pattern to quantify the three textures (smoothness, solid feeling, glossiness) of sharpness (S13). The numerical value of the sharpness is displayed on the monitor device 13 and is used for determining the quality of the painted surface (S14).

In the light source brightness determining section 30b, the light source 2
If the brightness of the light source 2 is not normal, that is, it is determined that the brightness is brighter or darker than the normal brightness (S12), the central processing unit 30a outputs an output necessary for setting the current brightness of the light source 2 to the normal brightness. An adjustment amount such as a current and a voltage is calculated, and the calculation result is output to the adjustment unit 34 as an adjustment signal (S15). Then, the adjustment unit 34 includes the central processing unit 30
Based on the adjustment signal from “a”, control for adjusting the output current of the power supply unit 32 and the like is performed. When the current and the voltage output from the power supply unit 32 to the light source 2 are adjusted by the adjustment unit 34, the adjusted brightness of the light source 2 is measured again by the brightness detection sensor 33, and the same as step S12. The light source brightness determination unit 30b determines whether the brightness of the light source 2 has become normal (S16). If the brightness of the light source 2 is adjusted to the normal brightness, the above-described step S
13, the processing of S14 is performed, and the central processing unit 30a quantifies the sharpness (S13), and displays the measured value on the monitor device 13 (S14).

If the brightness of the light source 2 cannot be adjusted to the normal brightness even if the output current of the power supply unit 32 is adjusted,
It is determined as NG in step S16. In this case, since the adjustment of the brightness of the light source 2 has exceeded the limit that can be automatically performed, the central processing unit 30a turns on the warning lamp 31 and
The contents of the warning are displayed on the monitor device 13, a predetermined warning is notified to the operator, and the measurement is terminated (S17). Thereafter, the operator performs appropriate measures such as disassembly adjustment and lamp replacement according to the contents of the warning.

As described above, according to the painted surface property measuring apparatus of this embodiment, the brightness of the light source 2 is
3 and is constantly monitored, and when the brightness of the light source 2 changes due to aging of the lamp 2a or the like, the output current of the power supply unit 32 and the output current of the power supply unit 32 are maintained so as to maintain the brightness at a normal value. The voltage is adjusted automatically. Therefore, it is not necessary to perform a calibration operation for checking the brightness of the light source 2 using the reference plate, and the original measurement operation can be performed quickly.

Further, even when the brightness of the light source 2 slightly changes, the brightness of the light source 2 is automatically adjusted to follow the change. Measurement, and the reliability of the measurement was significantly improved. Moreover, the light source 2
Since the brightness of the image is automatically adjusted, the disassembling and adjusting operation is not required. Further, if the voltage is increased, lamps which can still be used sufficiently are not wasted, and the running cost can be reduced.

When the brightness of the light source 2 exceeds the limit for automatically adjusting the brightness, a predetermined warning is output, so that the measurement accuracy is prevented from lowering, and the deterioration of the lamp 2a is clearly determined. can do.

Further, if the operation of confirming the brightness of the light source 2 using the reference plate is also used, the contrast of the measured image and the actual brightness of the light source 2 can be compared.
Instead of the deterioration of the lamp 2a, it is possible to determine whether the stripe grating 4, the convex lens 5, the protective glass, the CCD camera 6, or the like, which is an optical system component, has deteriorated, stained, or fogged.

[0034]

As described above, according to the present invention, a coated surface texture measuring device of the present invention, by the brightness of the light source is automatically adjusted, calibrated to confirm the brightness of the light source by using a reference plate There is no need to perform any work, and the original measurement work can be performed quickly. Also, since the brightness of the light source is adjusted according to the change in the brightness of the light source,
High-precision measurement of sharpness without errors can be performed, and the reliability of the measurement can be improved. In addition, since the brightness of the light source is automatically adjusted, unnecessary adjustment work and the like are not performed, and from this point, the original measurement work can be performed quickly. Further, the control means is an adjusting means.
The brightness of the light source does not reach the desired brightness even when
Sometimes a predetermined warning is issued, and the light source is discarded.
And reduce running costs
Can be.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing the overall configuration of a painted surface texture measuring device according to the present invention.

FIG. 2 is a structural view showing a measuring head of the painted surface property inspecting apparatus, wherein FIG. 2 (A) is a front view mainly showing an internal structure thereof, and FIG. 2 (B) is a bottom view thereof.

FIG. 3 is a flowchart showing the operation of the paint surface property measuring device.

FIG. 4 is a schematic block diagram showing the entire configuration of a conventional painted surface property measuring device.

FIG. 5 is a flowchart showing the operation of a conventional painted surface property measuring device.

[Explanation of symbols]

1 ... painted surface, 2 ... light source, 2a ...
Halogen bulb, 4 ... Striped grating, 6 ... CCD camera, 13 ... Monitor device, 30 ... Image processing device (control means), 30a ... Central processing unit, 30b ... Light source brightness judgment unit, 31 ... Warning light, 32 ... Power supply Division, 33
... Brightness detection sensor (light source brightness detection means), 34 ... adjustment unit (adjustment means).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-220443 (JP, A) JP-A-61-188532 (JP, A) JP-A-54-14259 (JP, A) (58) Investigation Field (Int.Cl. ⁷ , DB name) G01N 21/00-21/01 G01N 21/17-21/61 G01N 21/84-21/958 G01B 11/30-11/30 102

Claims (1)

(57) [Claims] 1. A coating surface property measuring device for projecting an image to be inspected on a painted surface by light from a light source and inspecting properties of the painted surface based on the inspected image reflected on the painted surface, Adjusting means for adjusting the brightness; light source brightness detecting means for measuring the brightness of the light source; and operating the adjusting means based on a signal from the light source brightness detecting means to set the brightness of the light source to a predetermined value. The brightness of the light source can be adjusted by adjusting the brightness of the light source and operating the adjusting means.
Issue a prescribed warning when the brightness does not reach the prescribed brightness
And control means that, painted surfaces texture measuring apparatus characterized by having a.