JPH06300713A - Inspecting system for defective stage - Google Patents

Abstract

PURPOSE:To obtain the inspection system wherein the surface defect of a sheetlike article such as a sheet of veneer core plywood or the like can be inspected automatically and not only the surface defect but also an inside defect can be detected. CONSTITUTION:The inspection system is provided with a transducer 1 which detects a three-dimensional defect on the surface of an object to be inspected by scanning the surface of the object to be inspected in a contact manner, with a mechanism which applies a beam of light to the object to be inspected, with a first CCD camera 3 which detects the inside defect of the object to be inspected by scanning the transmitted light of the beam of light, with a second CCD camera which scans the reflected light of the beam of light and with a judgement means 5 in which a prescribed logic has been built. The defective state of the object to be inspected is judged by the judgement means 5 on the basis of a scanning signal from the transducer 1 and of scanning signals from the first and second CCD cameras 3, 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for inspecting a surface defect of a plate material such as veneer plywood, and more particularly to a system for inspecting a surface defect using a contact type transducer and a CCD camera.

[0002]

2. Description of the Related Art As a conventional technique, the surface of a sheet-shaped film, various tapes, a cylindrical drum or the like which is an object to be inspected is irradiated with light, and the reflected light is passed through a CCD camera to detect foreign matters and scratches. , There are devices or systems for inspecting surface defects such as pinholes.

[0003]

When the above-mentioned conventional device or system is used for a plate-like article such as a plate material or veneer plywood, "grains", "knots" or the like are originally present on the surface and are called defects. It was difficult to separate the non-existence from defects such as "cracks", "mecre", "dimples", and "cavities" which are peculiar to the plate-like article and are generated in the processing step. Due to such circumstances, some of these plate-shaped articles are inspected visually as intermediate or final products even now. Visual inspection causes individual variations.
Long-time inspection is accompanied by eye fatigue and is unstable, such as a difference in inspection results between the beginning and the end, which is not preferable in terms of production cost.

[0004]

In order to solve the above-mentioned problems, the inventors of the present invention have made extensive studies as to how to overcome the drawbacks of the prior art using an optical conversion means called a CCD camera, and as a result, detect surface defects by contact. The inventors of the present invention have found out that a transducer that can be used in combination is used together, and have reached the present invention.

That is, in order to solve the above problems, the present invention provides a transducer for detecting a three-dimensional defect on the surface of the object to be inspected by scanning the surface of the object to be inspected, and the object to be inspected. A mechanism for irradiating an object with a light beam, a first CCD camera for detecting an internal defect of the inspection object by scanning the transmitted light of the light beam, and a second CCD camera for scanning a reflected light of the light beam. A defect state of the object to be inspected is provided by the determination unit, which includes a camera and a determination unit having a predetermined logic built therein, and the scanning signal from the transducer and the scanning signals from the first and second CCD cameras. Defect state inspecting system, a moving mechanism for moving an object to be inspected for scanning, a scanning signal from a transducer, and a first and a second. Providing the scanning signal synchronization means for synchronizing the scanning signal from the CD camera provides the defect state inspection system according to claim.

As shown in FIG. 1, the defect state inspection system of the present invention includes a transducer 1 for detecting a three-dimensional defect on the surface of an object to be inspected by scanning the surface of the object to be inspected in a contact manner. Mechanism 2 for irradiating the inspection object with a light beam, first CCD camera 3 for detecting an internal defect of the inspection object by scanning the transmitted light of the light beam, and scanning with reflected light of the light beam from the inspection object Second CCD camera 4, a determination means 5 having a predetermined logic for processing the scanning signal from the transducer 1 and the scanning signals from the first and second CCD cameras, the first CCD camera 3 and the first CCD camera 3 and The second CCD camera 4 and the moving mechanism 6 for moving the surface of the object to be inspected smoothly while keeping the distance constant.

In the transducer 1, it is preferable that the portion that comes into contact with the object to be inspected has a width of about 1 mm and a diameter of about 5 mm and is a wheel mechanism that rotates smoothly.
Further, as shown in FIG. 2, when the contact wheel, which is the contactor 7, comes into contact with a large uneven portion, the wheel mechanism is moved away from the surface of the object to be tested so as not to be broken due to bending stress. It is desirable that the structure has an escape mechanism that allows the escape mechanism to escape, and has a restoring spring that can immediately return to the original state after passing through that portion.

[0008]

The transducer 1 can detect the uneven defect on the surface of the object to be inspected as a change in the electric signal. In addition, the transmitted light from the inspection object based on the irradiation of the light beam is transmitted to the first CCD.
The camera 3 can detect an internal defect of the inspection object as a change in the electric signal. Furthermore, by photographing the reflected light from the inspection object with the second CCD camera 4, a visual defect can be detected as a change in the electric signal.

However, in the information detected as such a visual defect, when the object to be inspected is a plate-like wood such as veneer plywood, "wood grain" originally present in the plate-like wood.
It includes the detection result of the surface condition which is not called a defect such as a "node" or "node". Therefore, even if a visual defect is detected, if neither the uneven defect nor the internal defect is detected at the same position, this is not determined as a defect. The visual defect information plays an important role as auxiliary information for inferring the reliability of the result and the degree of the defect when an uneven defect or an internal defect is detected. For example, if a visual defect is detected at the same position where an uneven defect is detected, it can be determined that this is a severe uneven defect. Further, if only the unevenness defect is detected and not detected by the other scanning means, it can be determined that the unevenness defect is not so noticeable in appearance. Or from another point of view, in order to improve the detection capability of the irregularity defect itself, both the irregularity defect and the visual defect are set to lower the detection threshold so that they can be easily detected. Only this can be regarded as a defect.

[0010]

EXAMPLE An example of the present invention will be described with reference to FIG. FIG. 3 shows a transducer 11 for detecting a three-dimensional defect on the surface of the object to be inspected by scanning the surface of the object to be inspected, a mechanism 12 for irradiating the object to be inspected with a light beam, and the light beam. First CCD camera 1 for detecting internal defects in an object to be inspected by scanning transmitted light of
3. Second CCD camera 1 for scanning the reflected light of the light rays
4. Scan signal from transducer 11 and first CC
Judgment means 15 incorporating a predetermined logic for processing the scanning signals from the D camera 13 and the second CCD camera 14, a veneer plywood 23 having a thickness of 4 mm, a width of 900 mm and a length of 800 mm, which is an inspection object, and an inspection object. The defect condition inspection system of the present invention is shown to consist of a mechanism 16 for moving objects.

In this defect state inspection system, 180 transducers 11 are arranged at intervals of 5 mm in the longitudinal direction of the veneer plywood 23 in order to finely perform contact scanning over the entire surface of the veneer plywood 23 which is the object to be inspected. It is arranged linearly at a right angle.

A first CCD camera 13 having 2048 pixels is arranged above the veneer plywood 23 at a position about 10 mm away from the position where the transducer 11 is installed, and a second CCD with the same number of pixels is arranged below the veneer plywood 3. CCD camera 14
Are arranged.

A halogen light source is used as a light source used in the mechanism for irradiating the object to be inspected with a light beam, and the irradiation light is linearly and uniformly with respect to the longitudinal direction of the veneer plywood 23 by an optical fiber cable from the lamp house. And irradiate with a coaxial mirror using a half mirror. In order to increase the irradiation efficiency, a cylindrical lens (not shown) may be provided at an appropriate position between the half mirror and the veneer plywood 23.

As the moving mechanism 16 for moving the veneer plywood 23 which is the object to be inspected, a pair of cylindrical rolls are provided above and below the veneer plywood 23 with the detection part interposed therebetween, and the plywood is flapping with the movement. However, the distance between the surface and the first and second CCD cameras 13 and 14 does not change by 1 mm or more.

Furthermore, in order to avoid erroneously recognizing wood chips and dust adhering to the surface of the veneer plywood 23 as a three-dimensional defect, the surface of the veneer plywood 23 is compressed to a position before entering the detection portion. An air nozzle 18 is provided to remove the wood chips and dust.

The scanning signal from the transducer 11 is guided to the contact scanning signal processing device 19, the scanning signal from the first CCD camera 13 is guided to the transmission scanning signal processing device 20, and the scanning from the second CCD camera 14 is performed. The signal is guided to the reflection scanning signal processing device 21 to detect the presence / absence of a defect. A threshold value for defect detection is preset in each scanning signal processing device, and the accuracy of detection can be controlled by adjusting the threshold value.

The three scanning signals that have passed through the contact scanning signal processing device 19, the transmission scanning signal processing device 20 and the reflection scanning signal processing device 21 are guided to the judging means 15 through the scanning signal synchronizing means 22 and the content of the defect is determined. It is determined and output to the gate corresponding to the content.

The scanning position of the transducer 11 and the first
Since the scanning positions of the second CCD camera are different from each other and these three scanning signals are not synchronized, the scanning signal synchronizing means 22 is used to synchronize these three scanning signals.
It is provided in front of the determination means 15.

Instead of providing the determining means 15, the measurement results for one piece of veneer plywood, which is the object to be inspected, are transferred to an external computer (not shown) provided separately, and the internal processing of the computer causes the determining means 15 to operate. It is also possible to have an equivalent role.

Table 1 below shows what defect contents each gate output corresponds to. In Table 1, "1"
Indicates that detection was performed by each scanning means, and "0" indicates that detection was not performed.

[0021]

[Table 1]

[0022]

According to the present invention, it is possible to automatically inspect the surface defects of a plate-like article such as veneer plywood, which has conventionally been visually inspected. Moreover, not only surface defects but also internal defects can be captured.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a basic configuration of the present invention.

FIG. 2 is a schematic diagram showing a structure of a contactor used for a transducer.

FIG. 3 is a schematic view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transducer 2 Mechanism for irradiating light beam 3 First CCD camera 4 Second CCD camera 5 Judging means 6 Moving mechanism 7 Contactor 8 Restoring spring 9 Escape mechanism 11 Transducer 12 Mechanism for irradiating light beam 13 First CCD camera 14 Second CCD camera 15 Judgment means 16 Moving mechanism 18 Compressed air nozzle 19 Contact scanning signal processing device 20 Transmission scanning signal processing device 21 Reflection scanning signal processing device 22 Scanning signal synchronizing means 23 Veneer plywood (inspection object) Gate output Gate output Gate output Gate output Gate output

Claims (2)

[Claims] 1. A transducer for detecting a three-dimensional defect on the surface of the inspection object by scanning the surface of the inspection object by contact, and a mechanism for irradiating the inspection object with a light beam. A first CCD camera that detects an internal defect of the object to be inspected by scanning the transmitted light of the light beam, a second CCD camera that scans the reflected light of the light beam, and a determination unit that incorporates predetermined logic. And a scanning signal from the transducer and the first and second scanning signals.
And a scanning signal from the CCD camera for determining the defect state of the object to be inspected by the determination means. 2. A moving mechanism for moving an object to be inspected for scanning, and a scanning signal synchronizing means for synchronizing the scanning signals from the transducers with the scanning signals from the first and second CCD cameras. The defect condition inspection system according to claim 1, which is characterized in that.