JPH0820382B2 - How to detect defects in logs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention, as a raw wood treatment before cutting a long raw wood into a predetermined length in order to supply it to, for example, veneer lace, whether or not there is a defect of the raw wood and the defect. If there is such a defect, the present invention relates to a defect detection method for a raw tree, in which the defect portion is detected and the outer peripheral position of the raw tree associated with the defect position is marked.

[Prior Art] As a conventional method for detecting iron pieces existing on the surface of a log,
For example, the method described in JP-A-53-39598 is known.

In this method, a permanent magnet wound around a coil is attached close to the rotating periphery of the log of the rotary race, and when the iron piece is mixed in the log, the iron piece generates a current in the coil that is moving together with the log. By doing so, the presence of iron pieces is detected to prevent damage to the blade of the rotary race.

Further, there is no technique corresponding to the present invention prior to the present invention regarding a method of detecting defects other than metallic foreign matter, and an operator visually inspects the surface of the raw wood according to the actual situation at the site to determine whether the S pipe, the U pipe,
When a foreign substance such as a nail is found, it is usually removed by using a skip or a grind.

[Problems to be Solved by the Invention] In the method disclosed in Japanese Patent Laid-Open No. 53-39598, since the iron pieces are detected after the logs are chucked on the rotary race, the operation rate of the rotary race is lowered and the method is put into practical use. There were many problems for.

In addition, with the visual inspection method, it is difficult to judge and remove foreign matter unless it is skilled, and it is a labor-intensive work.Because only the outer peripheral portion of the raw wood is inspected, rot, knots,
It is impossible to detect cavities and detect foreign objects such as S pipes, U pipes, and nails that are deeply embedded in the raw wood, which causes the following problems.

(1) There are problems that the blade of the saw may be damaged or the chain may be broken by the S pipe, U pipe, nails, etc. existing inside the raw wood.

(2) There is a problem that the blade of the veneer lace is chipped due to the S pipe, U pipe, nails, or knots of the raw wood existing inside the raw wood.

(3) Continuous veneer with high grade such as front plate, etc., while defects such as rot and cavities appeared while peeling veneered continuous veneer with high grade such as front plate, and the quality of veneer deteriorated. There is a problem of lowering the yield of.

(4) If there is a fragile part on the end face of the raw wood after cutting, there is a problem that in the veneer race, the chucking part has a center rotation, which makes it impossible to turn to the minimum peeling center diameter. It was

[Means for Solving the Problems] The present invention is intended to solve such a conventional problem, and is a defect detection method performed in a pre-process of cutting a long log into a predetermined length, the log being Measuring a large number of transmitted X-ray intensities from a plurality of directions with respect to the same cross section of the raw wood at a predetermined interval along the longitudinal direction of the raw wood by an X-ray irradiator and an X-ray detector that are arranged to face each other across the raw wood.
The pattern of the distribution image of the X-ray absorption coefficient of the log obtained from the measurement data of the transmitted X-ray intensity is compared with a previously registered defect pattern, and the presence or absence of a defect and, if there is a defect, the position of the defect A method of detecting a defect in a raw tree, which comprises a step of making a judgment and a step of marking the outer peripheral position of the raw tree associated with the position where the defect exists when it is determined that there is a defect, A defect detecting method performed in a pre-process of cutting a raw wood into a predetermined length, wherein an X-ray irradiation device and an X-ray detection device which are arranged to face each other with the raw wood sandwiched therebetween transmit X-rays along a longitudinal direction of the raw wood. A step of measuring the intensity, and a step of measuring the intensity of the transmitted X-rays from a plurality of directions in the same cross section of the raw wood in the vicinity of the portion determined to be defective from the result of the measurement of the transmitted X-ray intensity. And a pattern of the distribution image of the X-ray absorption coefficient of the log obtained from the measurement data of the transmitted X-ray intensity and a previously registered defect pattern are compared, and if there is a defect and if there is a defect, Defects of raw wood, characterized in that it comprises a step of judging the position and a step of marking the outer peripheral position of the raw wood related to the position where the defect exists if it is judged that there is a defect. It is intended to provide a detection method.

In the present invention, the defects existing in the raw wood, that is, the outer periphery of the raw wood, and the metal pieces present in the inside, rot,
The presence or absence of knots or bumps and the contents thereof are determined by comparing and determining the shape, size, density, etc. of the pattern of the distribution image of the X-ray absorption coefficient with a registered defect pattern by a computer.

If the defect of the raw wood is metal pieces such as S pipe, U pipe, nails,
Because of the large absorption of X-rays, the contrast with the surrounding background is large, the size is smaller than the log diameter, the shape is also special, and there are many data on the outer circumference.
It is registered in the computer as a defect pattern in advance, and the pattern of the distribution image of the X-ray absorption count is compared with these registered defect patterns by the computer and when the degree of coincidence is high, it is judged as a metal piece.

On the other hand, in the case of defects other than metal pieces such as rot, knots, and bumps, the contrast between the background and the boundary is smaller than that of metal pieces, and there are also characteristic sizes and shapes. Data is registered in the computer as a defect pattern in advance, and the computer compares the distribution image pattern of the X-ray absorption coefficient with these registered defect patterns, and when the degree of coincidence is high, the pattern is corrupted, knotted or bumpy. And so on.

If necessary, the shape of the distribution image pattern of the X-ray absorption coefficient, the size, the density, the judgment result of the quality of the wood component, etc. are displayed on the CRT screen, and these image data are stored in a computer memory. It is also possible to store it in.

[Operation] In the present invention, first, the pattern and the position of the distribution image of the X-ray absorption coefficient of the defect existing in the long log are obtained. As a method for obtaining the pattern and the position of the distribution image of the X-ray absorption coefficient, a large number of transmitted X-ray intensities from a plurality of directions with respect to the same cross section of the raw wood are measured at predetermined intervals along the longitudinal direction, or The transmitted X-ray intensity is measured along the longitudinal direction of the raw tree, and from the results of the measurement, the part that seems to have a defect in the longitudinal direction of the raw tree is specified, and the transmitted X-rays from the multiple directions on the same cross section near the part are identified. There is a method of measuring the intensity and obtaining the pattern of the distribution image of the X-ray absorption coefficient of the defect in the raw wood from these measurement data.

Then, the presence / absence and position of the defect are judged by comparing the pattern of the distribution image of these X-ray absorption counts with the defect pattern registered in advance. For example, when it is judged that the defect exists, the defect is detected by the outer periphery. When the defect exists in the outer peripheral surface, the position is marked on the outer peripheral surface, and when the defect exists inside the raw wood, the peripheral position closest to the defect is marked.

After this, defects existing in the outer peripheral part, such as S pipe, U pipe,
For nails, remove and for internal defects, cut high quality required veneer such as face plate 6
The tree will be cut in consideration of the fact that the shrub logs do not contain defects.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1 is a side view of an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line aa in FIG. FIG. 3 is a partial side view of the transfer device.

In these figures, 10 is a first conveyor for conveying long logs, 20 is a second conveyor, and a plurality of V-shaped plates 31 are attached to a plurality of roller chains 3 at equal intervals.

The roller chain 30 is driven by a motor or the like via a sprocket 33, and travels on the rel 33 in the direction of the arrow with the long log placed on the V-shaped plate 31.

Reference numerals 11 and 21 are pulse detectors for detecting the respective transport speeds of the first transport device and the second transport device. The CPU 46 fetches these transportation speed data and controls the speeds of the first and second transportation devices so that they match.

An X-ray generator 42 includes X-ray tubes 40A and 40B which emit X-ray pulses in a fan shape toward the log by making the X-ray pulse orthogonal to the log. Reference numeral 43 is an image data acquisition device, and comprises X-ray detectors 41A and 41B arranged to measure the intensity of transmitted X-rays emitted from the X-ray tubes 40A and 40B.

The X-ray detectors 41A and 41B are X-rays projected in a fan shape, respectively.
A line sensor system is used in which a large number of detectors are linearly arranged so that the intensity of a line can be detected for each unit length.

That is, from the X-ray tubes 40A and 40B, the thin collimated X-ray fan beam is orthogonal to the long wood transport direction on a plane orthogonal to the longitudinal direction of the wood. These X-ray fan beams projected so as to cross each other and transmitted through the log are the X-ray detectors 41A and 41B.
The transmitted X-ray intensity for each predetermined opening angle of the fan shape is measured by the image data acquisition device 43, and the distribution image of the X-ray absorption coefficient of the X-ray absorption coefficient in the raw wood is obtained based on the respective measured values. The image is reconstructed by the image processor 45 and displayed on the display 47. The technique of displaying the distribution image of the X-ray absorption coefficient of the X-ray absorption coefficient on the cross section at the predetermined position in the longitudinal direction of the raw wood on the display 47 is widely known as a CT scanner in the medical field.

Even if the X-ray fan beam is projected from only one direction, it is possible to judge the defect position and approximate shape as a projected image from the position direction, but by projecting from multiple directions like a CT scanner. , It becomes possible to determine the exact position and size on the cross section of the raw wood.

That is, in this embodiment, the X-ray fan beam is irradiated from two directions (orthogonal directions) at predetermined intervals along the longitudinal direction of the raw wood, and the X-ray absorption coefficient X-ray in each cross section in the longitudinal direction of the raw wood. As a result of obtaining the distribution image of the absorption coefficient, the shape, position, etc. of the defect become three-dimensionally clear.

Reference numeral 46 denotes a CPU, which compares the image reconstructed by the image processor 45 with the image of the defect pattern registered in the CPU 46 for each registered parameter, and the degree of coincidence determines the defect shape, position, etc. The quality of the wood part is also automatically determined. Reference numeral 50 is a marking device, and when a defective signal is output from the CPU 46, for example, paint is ejected from the injector 51 to the defective portion.

4 and 5 are front views showing an embodiment of the marking device. The marking device 50, as shown in FIG. 4, makes it possible to mark the defect on the outer periphery when it exists on the outer periphery, and on the outer periphery that is closest to the defect in the diameter direction of the raw wood when it exists inside. It is preferable to install many vessels in the outer peripheral direction of the log, but as shown in FIG.
A small number of injectors may be installed so as to be rotatable 360 ° in the outer peripheral direction of the raw wood.

Next, a method for detecting defects in the raw wood of the embodiment configured as described above will be described with reference to the flowcharts of FIGS. 6 and 7.

In the embodiment shown in FIG. 6, first, the long log L0 is loaded into the first transfer device 10 by a hoist, a forklift, etc., and the first transfer device 10 and the second transfer device 20 are loaded into the CPU 46.
Control is performed to synchronize the transport speed, and the transport is started in the direction of the arrow at a constant speed (A).

When the tip of the long log L0 reaches the X-ray generator 42, X-ray pulses synchronized with the transport speed of the log are projected from each of the two directions (orthogonal directions) in a fan shape (log L1).
(B), the transmitted X-ray intensity from two different diameter directions of the raw wood is measured by the image data acquisition device 43 (C), and the pattern of the distribution image of the X-ray absorption count is calculated by the image processor 45 and the CPU 46 ( D), the cross-sectional image of the raw wood is reconstructed and displayed on the display 47 (E). The display on the display 47 is used, for example, when the marking device 50 is remotely controlled by the operator's visual control.

In the CPU 46, the reconstructed image (X-ray absorption count distribution image pattern) and the registered defect pattern image are
Parameters that characterize presence / absence of defects, contents, quality of wood part, etc. such as shape, size, and shading are compared, and each defect is automatically discriminated (G). For example, when a defect part exists, after a certain period of time. A signal is sent to the marking device 50,
The injector 51 injects paint on the defect portion of the raw wood L2 or in the vicinity of the defect portion to mark the outer peripheral surface of the raw wood (H).
In the case of manually operating the cutting device or foreign matter removing device in the next step, if there is a defect part on the lower side of the raw wood, in addition to marking the defect part or the vicinity of the defect part,
Marking may be made on the upper portion of the outer peripheral surface of the raw material in the diameter direction of the defect portion so that the operator can easily confirm it.

In the case of this embodiment, the signal (position data) to the marking device 50 is stored in the CPU 46, and the foreign matter removing device 80 (H) and the log cutting device 70 (I) in the next step are stored.
It can also be used as data for automatic control (log L3).

Next, another embodiment will be described with reference to the flow chart shown in FIG.

This embodiment can also be basically implemented by the apparatus shown in FIG.

First, the raw wood is carried by the carrying device so as to pass between the X-ray generator and the X-ray detector (A). In this embodiment, first, by a scanogram system using a CT scanner or a line sensor system X-ray television system,
X-rays are projected from one direction (B). With such a projection method, metal is detected only as a linear intensity distribution in the cross-sectional direction, but it is possible to estimate the presence or absence of defects by evaluating a series of images in the longitudinal direction as a series (D). Therefore, if a defect-like object is detected, a cross-sectional image of that part is tomographically taken by a CT scanner (E),
More specifically, the pattern of the distribution image of the X-ray absorption count of the part is calculated (F), and the shape, size, shade, etc. of the pattern of the distribution image of the X-ray absorption count are registered in advance as defect patterns. The presence or absence and the position of the defect are compared (G). If it is determined that the defect exists and the defect exists on the outer circumference, the position on the outer peripheral surface is determined. If the defect exists inside the log, the defect is the most The marking (H) is applied to the near outer peripheral position.

Also in the case of this embodiment, the signal (position data) to the marking device 50 is stored in the CPU 46 and used as data when automatically controlling the foreign matter removing device 80 and the log cutting device 70 in the next step. You can also do it.

Next, regarding the defect pattern of the raw wood, FIG.
This will be described with reference to (C).

Ordinary plywood (for example, 3 ply x 6 ply 5 ply (5
In the case of (layer)), the front plate (F: face), the back plate (B: back), the core plate (CC: center core) whose fiber direction is the same as that of the 6 shaku direction, and the 3 shaku direction and the fiber direction are It is composed of the same attachment plate (C: core), and is laminated and adhered in order from the top to F, C, CC, C, B with the fiber direction at right angles.

The order of high grade of these veneers is F, B, CC, C, that is, the veneer with high grade can only be turned from 6-inch long log, and the chopping of the log is
Inevitably, 6 shaku logs will be removed preferentially.

Fig. 6 (A) to (C) For each of the raw trees, the upper tree A1, B1, C1 is cut by the conventional cutting method (shown by the chain double-dashed line) to the lower tree A2, B2,
C2 is a cutting method (shown by a thick broken line) according to the present invention, and all the defects exist inside.

In (A) and (B), with the cutting method according to the present invention, one more 6-inch log can be removed, which is more defect-free than before.

In the case of (C), the cutting method according to the present invention enables the removal of two more 6-bar logs, which are more flawless than conventional ones.

[Effects of the Invention] As described above, according to the present invention, the following effects can be obtained.

(1) Detect foreign matter existing in long logs before cutting,
Since it can be removed, the blade of the cutting device is not damaged at the time of dicing, the number of blade exchanges is reduced, and the operating rate is increased.

(2) Since it is possible to take the size of the cut ball after being familiar with the shortcomings existing in long logs, it is possible to efficiently remove wood according to the application.

(3) Since all the foreign matter existing in the long log can be removed in advance, damage to the blade of the veneer lace is eliminated and the quality of the veneer is improved. In addition, since the life of the blade is extended, the number of blade exchanges is reduced and the operating rate is increased.

(4) Since there is no fragile part on the end face of the raw wood after cutting, the turning does not occur and the turning to the minimum decentering diameter is possible.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention, FIG. 2 is a sectional view taken along line 1a-a, FIG. 3 is a partial side view of a conveying device, and FIGS. FIG. 6 is a front view showing an example, FIG. 6 is a flow chart of an embodiment of the present invention, FIG. 7 is a flow chart of another embodiment of the present invention, and FIG.
(C) is a top view of a log cutting pattern. 10 …… First carrier 20 …… Second carrier 40A, 40B …… X-ray tube 41A, 41B …… X-ray detector 50 …… Marking device 70 …… Cutting device L, L0, L1, L2, L3 …… Long length log F …… Internal defects

Claims (2)

[Claims] 1. A defect detection method performed in a pre-process of cutting a long log into a predetermined length, wherein the X-ray irradiation device and the X-ray detection device are arranged so as to face each other with the log being interposed therebetween. A step of measuring a large number of transmitted X-ray intensities from a plurality of directions on the same cross section at a predetermined interval along the longitudinal direction of the raw tree, and an X-ray absorption count distribution image of the raw tree obtained from the measured data of the transmitted X-ray intensity. Of the defect pattern registered in advance and the presence or absence of a defect and the position of the defect if there is a defect, and the position where the defect exists if it is judged that there is a defect. A method of detecting a defect in a raw tree, which comprises the step of marking the peripheral position of the relevant raw tree. 2. A defect detection method performed in a pre-process of cutting a long log into a predetermined length, wherein the X-ray irradiation device and the X-ray detection device are arranged so as to face each other with the log being interposed therebetween. Measuring the transmitted X-ray intensity along the longitudinal direction, and measuring the transmitted X-ray intensity from a plurality of directions on the same cross section of the raw wood in the vicinity of a portion determined to be defective from the measurement result of the transmitted X-ray intensity. Measuring step,
The pattern of the distribution image of the X-ray absorption coefficient of the log obtained from the measurement data of the transmitted X-ray intensity is compared with a previously registered defect pattern, and the presence or absence of a defect and, if there is a defect, the position A method of detecting a defect in a raw tree characterized by comprising a step of making a determination and a step of marking the outer peripheral position of the raw tree associated with the position where the defect exists if it is determined that there is a defect. .