JPH0145023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to an appearance inspection device that inspects a substantially cylindrical article such as a drug capsule based on sensor output obtained by scanning the article with an optical sensor. .

[Prior art and its problems]

Inspection of such articles is generally carried out as follows.

FIG. 1A is a schematic diagram illustrating a method of scanning an article;
FIG. 1B is an external view showing the appearance of the capsule, and FIGS. 1C to 1F are waveform diagrams showing the sensor output when the capsule is scanned.

That is, the cylindrical article 1 is illuminated by the illuminators 2 ₁ and 2 ₂ , and the optical sensor 3 detects, for example, reflected light from the article 1 . Article 1 is
While being rotated by a predetermined means with its longitudinal axis as the rotation axis, the article 1 is placed on a conveying device (not shown) and conveyed in the direction of the arrow, so that the article 1 is scanned by the sensor 3 in a spiral shape. (Helical Skyan). Now, let us consider the case where a drug capsule 1 as shown in FIG. 1B is helically scanned. By the way, the capsule 1 is composed of a cap 11 and a body 12 as shown in the figure, and the cap 11 is further provided with a lock hole (notch) 1 for mutually locking the cap and the body 12.
3 is provided. Note that the capsule 1 shown in the figure is a so-called empty capsule before being filled with a drug, and at this time, the cap 11 and the body 1 are
The bonding force between the two is small, and they are in a so-called temporary bonded state by the notch 13. When the capsule 1 constructed in this manner is subjected to a helical scan, an output having a shape as shown in FIG. 1C is obtained from the optical sensor 3. In other words, since the reflectance of the cap 11 is higher than that of the body 12, there will be a step in the output waveform, as shown in A and B in the figure. Therefore, if there is a hole or other flaw on the body, as shown in D of the same figure, for example, the reflectance of light will be low in this part, or in other words, a concave part will be formed as shown in F of the same figure. scratches can be detected. Note that E and F in the same figure are enlarged waveform diagrams showing the portions C and D in D enlarged. Incidentally, at the boundary (step) between the cap and the body of the capsule, indicated by C in Figure D, there is a concave part in the waveform as shown in Figure E, but this does not indicate an abnormality in the capsule. It is necessary to prevent it from being detected as a flaw. Therefore,
A position sensor is provided to detect such a stepped portion, and a mask signal is generated in synchronization with the position sensor signal to prevent a flaw signal from being generated in this portion.

FIG. 2 is a waveform diagram illustrating the timing of generation of the mask signal. In the same figure, A is the above-mentioned position sensor signal, and B is a mask signal. Further, C and D are sensor output signals, C indicates the case where the cap portion is transported first, and D indicates the case where the body portion is transported first.

In other words, the direction in which the capsules are conveyed is not necessarily determined; some are conveyed with the cap first, while others are conveyed with the body first.
In this case, there is no particular problem if the step part is located approximately at the center of the capsule in the longitudinal direction, but as shown in Fig.
If there is a difference in the center position as shown in d, there is a problem in that the width of the mask signal must be widened as shown in fig. In addition, if a timing shift occurs in the position sensor signal shown in A of the same figure, as shown by the dotted line, and each mask signal shifts as shown in F for the signal C, and G for the signal D, the overall It becomes necessary to further widen the width of the mask signal as shown in FIG. A mask signal is a signal that does not see the concave part of the signal within the time or interval determined by its width. Therefore, a wide signal width means that the signal that should be detected is also overlooked. This results in a corresponding decrease in detection accuracy.

[Purpose of the invention]

The present invention was made under these circumstances, and aims to provide an appearance inspection device that can accurately detect defects such as scratches by generating an optimal mask signal that takes into consideration the shape of the object to be inspected. This is the purpose.

[Key points of the invention]

The key point is that an optical sensor scans a substantially cylindrical article that is conveyed in the axial direction while being rotated about a longitudinal axis, and a first differential signal obtained by differentiating the output of the optical sensor. defect detection means for detecting a defect signal including a seam signal of an article; seam detection means for detecting a seam signal of the article based on a second differential signal obtained by differentiating the output of the optical sensor; and detection by the seam detection means. Inspection is performed by providing a masking means for generating a mask signal based on the seam signal generated and excluding the seam signal from the defect signal output from the defect detection means using the mask signal.

[Embodiments of the invention]

FIG. 3 is a configuration diagram showing an embodiment of this invention, and FIG.
6 are waveform diagrams of various parts for explaining the operation of FIG. 3. In Fig. 3, 4 is a position sensor;
1 is an amplifier, 12 ₁ and 12 ₂ are differentiating circuits, 13 ₁ ~
13 ₄ is a comparator, 14 is a timer, 15 ₁ to 1
5 ₄ is an AND gate, 16 ₁ and 16 ₂ are mask signal generation circuits, 17 is a transport direction discrimination circuit, 18 is a storage circuit, and the other parts are the same as in FIG.

First, its operation will be explained with reference to FIGS. 3 and 4. The cylindrical article is a capsule as shown in FIG. 1B, and the same applies hereinafter.

The reflected light from the capsule 1 irradiated by the illuminators 2 ₁ and 2 ₂ is converted into an electrical signal by the optical sensor 3 . As mentioned above, since the capsule 1 is conveyed in the axial direction while being rotated about the longitudinal axis as the rotation axis, the output from the sensor 3 is obtained as shown by a in FIG. 4A. Note that FIG. 4B is a partially enlarged waveform diagram similar to FIGS. 1E and F. The output signal a from the sensor 3 is amplified by the amplifier 11 and differentiated by the differentiating circuit ₁₂₁ for the purpose of detecting flaws, so that a waveform as shown in b in Fig. 4 is obtained from the output. It will be done. The positive part of the differential signal b is compared with the predetermined levels TH ₁ and TH ₂ by the comparator 13 ₂ and the negative part by the comparator 13 ₁ , respectively, and outputs d and c as shown in FIG. 4 E and D are obtained. It will be done. Furthermore, this signal c is
Timer circuit 14 like a monostable multivibrator
Therefore, the output e shown in FIG. 4 is obtained from the timer 14. This signal e and the signal d obtained from the comparator 13 ₂ are ANDed by an AND gate 15 ₁ , and the signal indicated by h in FIG. 4G is output from the AND gate 15 1 .
Note that this signal h is stored in the storage circuit 18 in synchronization with the clock pulse.

Next, the explanation of the operation will be continued with reference to FIGS. 3 and 5.

On the other hand, the signal amplified by the amplifier 11 is sent to a differentiating circuit 12 for the purpose of determining the transport direction of the capsule.
₂ , and the signal i as _shown in _FIG .
When compared with TH ₃ and TH ₄ , signals k and j as shown in F and E in FIG. 5 are obtained. At this time, position sensor 4
has already output the position sensor signal f as shown in FIG. 5A depending on the presence or absence of the capsule, so the mask signal generation circuit ₁₆₁ generates the mask signal n as shown in FIG. 5B based on this signal f. It has occurred. Therefore, the signals k and j obtained as described above are
given to AND gates 15 ₃ and 15 ₂ respectively,
From the output, signals m and l as shown in Fig. 5
is obtained. Note that this is a case where the capsule is scanned with its cap side first, but the case where the capsule side is scanned first can also be considered in the same manner as above. That is, _the output a of the sensor 3 in this case is as shown in _FIG . 13 ₄
The signal j, k obtained by comparing with a predetermined level at
are as shown in E' and F' in the figure, respectively. Therefore, by taking the AND of the signals j, k and the signal n, signals l, m such as G' and H' in the figure can be obtained. In other words, if the capsule is transported with the cap first, only the signal m will be "1" as shown in Figure 1, and if the capsule is transported with the body first, only the signal l will be "1" as shown in Figure 7'. ”, so
From this, the direction of transport of the capsule can be determined.

Next, the flaw determination operation will be described with reference to FIGS. 3 and 6.

As described above, AND gate 15 ₂ or 1
When the output obtained from ₅₃ , that is, either the signal l or m becomes "1", the transport direction discrimination circuit 17 detects this and gives a signal to that effect to the mask signal generation circuit ₁₆₂ . The mask signal generating circuit ₁₆₂ generates a signal p as shown in FIG.
In other words, if the capsule is transported with the cap first as shown in Figure A, then the signal shown in Figure B is sent, and if the capsule is transported with the body first as shown in Figure A', then the signal shown in Figure B' is sent. These signals are output respectively.
At this time, the memory circuit ₁₈ contains a signal Q ₁ generated at the stepped portion as shown in FIG. It is remembered that the signal _Q1 generated at the stepped portion is masked by the mask signal p, so only the signal R due to the flaw F is taken out from the AND gate ₁₅₄ as shown in D and D' in the same figure. become.

〔Effect of the invention〕

As described above, according to the present invention, an accurate mask signal can be generated by determining the conveyance direction of a cylindrical article, so the area in which flaws are detected is expanded, and therefore accuracy can be improved. This has the advantage of making it possible to perform high quality inspections. In addition, since it is possible to determine the conveyance direction, it is possible to set the flaw inspection area accordingly, and the flaw detection sensitivity can be changed depending on the inspection area, allowing for more accurate detection. becomes.

Note that the present invention can be applied to general inspection apparatuses for inspecting the appearance of articles similar to drug capsules as described above.

[Brief explanation of drawings]

FIG. 1A is a schematic diagram showing the scanning method of the inspection article;
Figure 1B is an external view showing the drug capsule, Figure 1C
~F is a waveform diagram showing the sensor output, FIG. 2 is a waveform diagram explaining the generation timing of the mask signal, FIG. 3 is a configuration diagram showing an embodiment of the present invention, and FIGS. 4 to 6 are FIG. FIG. 3 is a waveform diagram of each part for explaining the operation of the FIG. Code explanation, 1...Cylindrical article (drug capsule),
2 ₁ , 2 ₂ ... illuminator, 3 ... optical sensor, 4 ...
Position sensor, 11...Amplifier, 12 ₁ , 12 ₂ ...
Differential circuit, 13 ₁ to 13 ₄ ... Comparator, 14
...Timer circuit, 15 ₁ to 15 ₄ ...And gate, 16 ₁ , 16 ₂ ...Mask signal generation circuit, 17
. . . Conveyance direction determination circuit, 18 . . . Memory circuit.

Claims (1)

[Claims] 1. An optical sensor that scans a substantially cylindrical article that is conveyed in the axial direction while being rotated about a longitudinal axis, and a seam of the article based on a first differential signal obtained by differentiating the output of the optical sensor. defect detection means for detecting a defect signal including a signal; seam detection means for detecting a seam signal of the article based on a second differential signal obtained by differentiating the output of the optical sensor; and a seam detected by the seam detection means. 1. A visual inspection apparatus comprising: a masking means for generating a masking signal based on the signal, and using the masking signal to exclude a seam signal from the defective signal output from the defect detection means.