JPS5940149A - Apparatus for detecting live knot - Google Patents

Abstract

PURPOSE:To detect a live knot having characteristics of the asymmetric distribution of light reflecting intensity by imbalance at a photodetecting level of two photodetecting devices, by providing a means for irradiating scanning beam light and two photodetecting devices. CONSTITUTION:A polygon mirror 14 is rotated in an arrow mark B direction and laser light from a laser light emitting device (a light pojecting device emitting white light may be used) 13 is reflected by the mirror 14. Then, its reflected light is reflected by an FQ mirror 6 and scanning laser beam light is irradiated from the normal line direction to the surface of a blank single plate moving to an arrow mark A direction. The light reflected on the surface of the single plate 1 is received by photodetectors 3, 2 arranged symmetrically to an irradiating part to obtain each signal X1, X2 by amplifying each signal by amplifiers 7, 8. These signals X1, X2 are added by an adder 9 and also, subtracted by a subtracter 10 and the subtracted value X1-X2 is divided by the added value X1+ X2 with a divider 1 to calculate the absolute value of the divided value by an absolute value circuit 12.

Description

[Detailed description of the invention] The present invention relates to a live part detection device.

The length of what is generally called the fresh part or leaf node is the minimum length.
The M-sized knots have exactly the same color as the non-defective parts of the veneer material, but differ only in gloss, and cannot be detected at the shading level like the black original parts. Possible reasons for the difference in gloss between the green part and the non-defective part are as follows. In other words, the fiber direction of wood generally runs in the direction of the conduit, so as shown in Figure 1, the light r is transmitted to the material veneer fl +
When we irradiate a surface and examine the reflection characteristics of the reflected light...
It was found that there was a band with strong reflection intensity in the direction perpendicular to the fiber direction C. FIG. 2 shows the distribution of high reflection intensity PI in a non-defective part, where the shaded areas indicate areas where the reflection intensity is weak and the white areas indicate areas where the reflection intensity is strong. On the other hand, when we examine the reflection characteristics of the green part (4) as shown in Figure 3, we find that the band with strong reflection intensity is not symmetrical with respect to the axis perpendicular to the fiber direction C, as in the non-defective part; 4) It varies depending on the part. This is because the fiber direction C of the green part (4) is bent compared to the non-defective part, or is oriented in the normal direction of the material veneer +11 (
(looking upward), and it is thought that it will change like this. FIGS. 4(a) and 4(b) show the distribution of the reflection intensity of the live part (4), where the shaded areas indicate weak intensity and the white areas indicate strong/high intensity.

Because of such a difference in characteristics, the green part (4), which has no difference in color at all, can be recognized as a difference in gloss.

Therefore, conventionally, in order to detect the difference in gloss, the light emitting and receiving angle was set to the regular reflection position as shown in Figure 5, and the He-Ne
The laser beam emitted from the laser beam emitting device (I) is converted into a palm beam R using a semi-mirror (14), and the surface of the material veneer is scanned in the width direction, and the reflected beam is specularly reflected as shown in Figure 6. A living area detection device was used that received light with a light receiver (2) located at the ItI! position.
1) Indicates the direction of movement.

However, in such a conventional device, the above-mentioned live part (4
) As can be easily seen from the characteristics of
When looking for 4), hold it in your hand and change the angle of the material veneer +11 to find and recognize the part with the greatest difference in gloss. ). In addition, in the case of specular reflection light reception, the material veneer to be inspected (
This method is not suitable for wood sheets because the amount of reflected light varies significantly due to the vertical movement of l.

The present invention is capable of removing raw material bleeds that exist in a sheet-like material veneer,
The purpose is to provide a raw part detection device IIT that can reliably detect stains without misrecognizing them as other stains. It is an object of the present invention to provide a living part detection device that can perform part detection.

FIG. 7 is a schematic configuration diagram of an embodiment of the device of the first inventionttS<
A light projector that emits white light may also be used.> The laser beam is reflected by the FQ mirror (6), and the material veneer (Tl) moves in the direction of arrow A in the normal direction to the top surface. It is designed to irradiate a laser beam light. +21 and +31 are light receivers arranged symmetrically with respect to the irradiated area as shown in Figure 8;
3), (21 is an amplifier +71, + which receives the light reflected on the surface of the material single plate (1) and outputs the signal as shown in Fig. 9, respectively.
81 to obtain respective signals X, , x. These signals x, , x2 are added by an adder (9) and subtracted by a subtracter (lO), and the subtracted value are compared using a cosiparator 05) to detect whether it is a green part (4) or a non-defective part. The asymmetry coefficient S is determined experimentally: S = 0.01 to 0.09 in the non-defective part, and S = 0.01 to 0.09 in the non-defective part (4
Since 11 such as ff5 = 0.12 to 0.25 was obtained in ) section, the slice level was set to S = 0.1, and the reference voltage corresponding to this value was input to the reference input of the cosciparator Q5). However, as described above, when S is 0.1 or more, a comparison output is generated and the raw portion (4) can be detected very stably. Same receiver (21, +31 <or amplifier +
91001> is set in advance so that the received light output level when irradiating the S+Sen beam light R using a perfect diffuser plate is the same value.

By the way, in the embodiments shown in Figures 7 to 9, the asymmetry coefficient S is determined and compared with a preset reference value using a comparator (16), that is, the balance or unbalance of the light receivers (2+, +31) is detected. Therefore, if an imbalance occurs in the reception of light 1 (21, +31) due to warping of the single plate +11, it may be mistakenly detected as a live part (+U, !t).

The second invention was made in view of this point, and is shown in Fig. 10 (a
) (b) shows the example device. In this embodiment, the labor beam R is irradiated through a half mirror (II) to a single plate of the material to be detected i1, and its specularly reflected light component is reflected by a half mirror (IO1).
, S, D, etc., and the position of the beam is detected so that the beam can be received by the sensor 0q). Beam position detection sensor (l
q> consists of P, S, and D temples that generate outputs of different levels depending on the light receiving position, and the output of the beam position detection sensor (1'?J) is corrected by amplifier C according to the amplified output. The coefficients α and (1-α) are calculated and inputted to the correction coefficient circuits (2oa) (20b) which multiply the input signals respectively.The correction coefficient circuits (20a) (20b) are connected to the amplifier (7).
, (8) output Xs, Xx is given the above correction coefficient α, (1
αXz * corrected by these correction coefficient circuits (20a) (20b)
(1-α) Based on the signal xi, the subtractor θO is used to calculate 1α
A subtraction of Xλ-(1-α)Xl11 is performed, and the calculated value is further output x2, X.

divided by the divider H by the value added by the adder (9).
Ru. The divided value is then compared with a reference value by a comparator O (to) to detect the presence or absence of the raw part (4). In this way, in this embodiment, the reflected beam detection position of the beam position sensor Oη is determined between the unwarped material veneer (1) as shown in FIG. 10(a) and the warped material veneer (1) as shown in FIG. 10(b). Veneer fi+ detects the amount of warpage of the material veneer fil using a different fact, corrects the calculated value accordingly, and detects the correct raw part (4) regardless of the warp of the material veneer (1). can be done.

Since the present invention is equipped with the means for irradiating the solar beam light constructed as described above and two light receivers, the original reflection is avoided! i! I: A live area characterized by an asymmetrical power distribution can be detected by the unbalanced light receiving level of both light receivers, and the calculation means can detect the difference in the light receiving output of both light receivers. Since subtraction is performed to enlarge the fibers, even if the fibers are oriented in the same direction as a non-defective product, the color is black (or dark) and would have been mistakenly detected as a live part in the past. Even if the light receiving output is small, it can still be determined as a non-defective product. This has the effect of being able to reliably detect the raw part. In addition, in the second invention, even if there is warpage that is often seen in sheet-like material veneers, the warp can be corrected by the beam position detection sensor, and the raw part of the sheet-like material veneer can be detected. This has the effect of making it even more reliable.

[Brief explanation of drawings]

1 to 2a4 are explanatory diagrams of the principle of live part detection, FIGS. 5 and 6 are schematic diagrams of the conventional example, and FIGS. 7 and 8 are schematic diagrams of the embodiment of the present invention. 9 is a circuit block diagram of the same as above, FIGS. 10(a) and (b) are schematic configuration diagrams of an embodiment of the second invention, and FIG. 11 is a circuit block diagram of the same as above,
(1) is the material veneer, +21 + (31 is the receiver, (4
) is the raw part, <101 is the subtractor, 19) is the adder, (11
1 is a divider, (I is an absolute value circuit, a field is a laser beam emitting device, 0 is a half mirror,
η is a beam position detection sensor, (20a) and (20b) are correction coefficient circuits, and R is a laser beam beam light. Agent Patent Attorney Ishi 1) Chief 7-2; Figure 1 11113 (a) (b) Figure 5 Figure IIIG Procedural Amendment (Voluntary) Convexed in 1982 Month 28th Live Part Detection Device a 3. Make the amendment N, ff Applicant Address 1048 Oaza Kadoma, Kadoma City, Osaka Name (583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4, Agent 8, Amendment of attached document with amendment details Original letter number: Japanese Patent Application No. 57-150884 1, page 5, line 11 of the rough specification rFl, I mirror (6)''k
r paraboloid theory (6)”. 2. Insert "1 condensing lens (211' @ via") next to "r07)" in the 9th line of the 7th page of the same page. 3. Correct all figures 981O in the drawing as shown in the attached sheet. Agent: Patent attorney Figure 10 (0) (b)

Claims (1)

[Scope of Claims] 1) means for irradiating the width direction surface of the raw material veneer to be inspected with the cecipim light from the normal direction; It includes light receivers installed at the front and back positions in the moving direction of the material veneer, and adds and subtracts the light receiving outputs of both light receivers, divides the subtracted value by the added value, and calculates the absolute value of the divided value. a cossiparator for detecting a live area by comparing the asymmetric coefficient value determined by the calculation means with a reference value previously set based on the asymmetry coefficient corresponding to the live area; This is a patented living area detection device. 2) A means for irradiating beam light through a half mirror from a direction normal to the width direction of the material veneer to be inspected, and a means for irradiating the beam light so as to be symmetrical to the irradiated area of the material veneer. Light receivers installed at the front and back positions in the direction of movement of the material veneer,
The reflected light of the regular reflection component of the irradiation area of the material veneer is
A beam position t:Jt is provided, which receives light by reflection from a half mirror and generates an output of a predetermined level according to the receiving position, and a predetermined level is set for the received light output of each light receiver according to the output of the beam position sensor. A correction coefficient circuit that multiplies a correction coefficient and the respective received light outputs corrected by the correction coefficient circuit are added and subtracted, and the subtracted value is divided by the added value, and the asymmetry coefficient is calculated by the absolute value of the divided value. and a comparator that detects the raw area by comparing the asymmetric coefficient value obtained by the calculation means with a reference value set in advance based on the asymmetric coefficient corresponding to the raw area. Characteristic live part detection device.