JPH0443816Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a defect detection device that optically detects defects such as pinholes and cracks existing on the surface of faucets, particularly at the edges.

(Prior Art) Pinhole defects, cracks, etc. may occur during the manufacturing process of water faucets, etc., and it is necessary to remove these defective products from the manufacturing line.

Defects such as faucets include pinhole defects and cracks that occur on the body, as well as defects such as chips and cracks that occur on the ends. Such edge defects are located at the edges when a faucet, etc. is rotated and the entire circumference is captured by a one-dimensional CCD image sensor camera.
A method is known in which detection is performed based on changes in pixel output of a CCD image sensor.

(Problem that the invention aims to solve) However, with such conventional defect detection methods, defects in the body of a faucet etc. can be detected with high accuracy, but defects in the end part of a faucet etc. can be detected with high accuracy. However, this method not only requires special detection processing and is complicated, but also makes it difficult to detect defects with high precision.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a defect detection device that can easily detect defects in the end of a faucet or the like with high precision.

The present invention will be explained below using a water faucet as an example.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the above objects, the present invention provides means for converging light from the faucet surface onto a light detection means having a plurality of pixels. A faucet defect detection device that detects defects such as pinholes on the faucet surface based on the received light output corresponding to the amount of incident light of each pixel by scanning the plurality of pixels at predetermined intervals, A jig having a light reflection coefficient approximately equal to the light reflection coefficient of the surface of the faucet is tightly coupled to the end of the faucet, and defects at the end of the faucet are detected in the same way as for the center of the faucet. Features.

(Example) Fig. 1 shows a jig 30 used in this invention with a faucet 31.
FIG. The surface of the jig 30 is coated with white paint or plating, and is set to have a light reflection coefficient equivalent to that of the surface of the faucet 31. In addition, the jig 30 is designed so that a shadow does not appear at the contact area between the jig 30 and the end 33 of the faucet 31.
The diameter of the contact end 30a of the water faucet 30 is formed into a tapered shape that is equal to or larger than the diameter of the center part of the jig 30.
The end portion 33 of 1 can be optically regarded as a part of the body portion 32. Reference numeral 34 denotes a rotating shaft, which rotates the jig 30 and faucet 31 together. The speed of this rotation is adjusted in synchronization with the scanning period of the CCD sensor, which will be explained later.

Fig. 2 is a block diagram showing a defect detection device according to an embodiment of the present invention, Fig. 3a is a waveform diagram of the received light level obtained from a normal faucet surface, and Fig. 3b is a crack at the end of the faucet. A waveform diagram of the light reception level when a defect such as a scratch exists. FIG. 3c is a waveform diagram of the light reception level when a defect such as a pinhole exists on the faucet end and the faucet body.

Defect detection according to the present invention will be explained with reference to FIG. 2 and FIGS. 3a, b, and c. Reference numeral 1 denotes a one-dimensional camera (CCD sensor) that is equipped with a plurality of pixels and serves as a light detection means that outputs an analog light reception signal corresponding to the amount of light incident on each pixel. To specifically explain the one-dimensional camera (CCD sensor) 1, for example,
2,048 pixels are arranged linearly, and the light from the surface of the object to be detected, which is approximately 80 mm in total length and consists of the jig 30 and water faucet 31 shown in Figure 1, is converged onto the 2,048 pixels via a lens, etc. Since the light is incident on the light beam, it has a resolution corresponding to the interval between adjacent pixels, that is, a resolution of approximately 40 microns. Further, the 2048 pixels are sequentially scanned at each predetermined period, and the light reception output of each pixel is extracted in synchronization with the timing of the scanning period, and each pixel is initialized at each scanning period. As shown in FIG. 2, the light reception signal from the one-dimensional camera (CCD sensor) 1 is input to an A/D (analog/digital) converter 2, and is sequentially converted to a multi-value level (e.g.
256 gradations) is converted into a digital value. This digital value data is sent to a shift register 3 that shifts a predetermined number of pixel data, for example N pieces, and a subtraction circuit 4. _The subtraction circuit 4 calculates the difference ΔD ( _{=D B −}
D _A ) is calculated. The sign discrimination circuit 5 discriminates the sign of the difference ΔD, and outputs the signal to the comparison circuit 6 only when the sign of ΔD is positive. The comparison circuit 6 compares the judgment value of the judgment value circuit 7 with the value of △D, and when the value of △D is greater than the judgment value, that is, the defect has started at the position corresponding to point A in Fig. 3b. Then, the count number of the pixel counter 8 is subtracted by N pixels, that is, the pixel address corresponding to point A in FIG. 3b is stored in the memory 9. The pixel counter 8 is supplied with a signal synchronized with the scanning period from an oscillator (not shown). Also, set the D _B value at this time as _the threshold D _S , and
The comparison circuit 10 sequentially compares the value and the current pixel data D _A. As shown in FIG. 3b, the pixel position B where D _S ≦D _A is determined to be the end of the defect. The subtraction circuit 20 uses the pixel address _XE corresponding to the pixel position B and the pixel position A stored in the memory 9.
The difference ΔX from the pixel address X _S corresponding to is calculated as the defect width. In the width comparison circuit 11, the defect width △X
Only when the value of ΔX is greater than or equal to a predetermined value, it is determined that there is a defect and a defect signal is output.
21 is an AND circuit.

Note that even if there is a defect such as a pinhole in the body of the faucet as shown in FIG. 3c, it can be detected reliably in the same manner as the defect detection at the end of the faucet described above.

(Effects of the Invention) As explained above, according to the present invention, defects in the faucet end can be detected easily and with high precision.

Note that the present invention is a device that can be used not only for faucets but also for objects with ends.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the jig used in the present invention when it is tightly connected to a faucet, Figure 2 is a block diagram showing a defect detection device according to an embodiment of the present invention, and Figure 3 a. is a waveform diagram of the received light level obtained from a normal faucet surface, Figure 3b is a waveform diagram of the received light level when there is a defect in the faucet end, and Figure 3c is a waveform diagram of the faucet end and faucet body. FIG. 4 is a waveform diagram of the received light level when there is a defect in both parts. 1... One-dimensional camera (CCD sensor), 2...
A/D converter, 3...shift register, 4...subtraction circuit, 5...sign discrimination circuit, 6, 10, 11...
... Comparison circuit, 7 ... Judgment value circuit, 8 ... Pixel counter, 9 ... Memory, 30 ... Jig, 31 ... Faucet, 32 ... Body part, 33 ... End part, 34 ... Rotation shaft.

Claims (1)

[Claims for Utility Model Registration] Light from the surface of an object to be detected is converged and incident on a light detection means having a plurality of pixels, and the plurality of pixels are scanned at predetermined intervals to receive light corresponding to the amount of light incident on each pixel. In a detected object defect detection device that detects defects on the surface of the detected object based on output, a jig having a light reflection coefficient approximately equal to the light reflection coefficient of the surface of the detected object is brought into close contact with an end of the detected object. What is claimed is: 1. A defect detection device for a detected object, characterized in that defect detection at an end of the detected object is processed in the same manner as at the center of the detected object.