JPH0718695B2 - Concavo-convex observation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention observes the presence or absence of wrinkles formed on the surface of a sheet material such as paper or cloth, and the presence or absence of undulations or irregularities formed on the flat surface of an object. The present invention relates to an unevenness observing device used to do this.

[0002]

2. Description of the Related Art For example, when printing on paper or the like, if wrinkles are formed on the surface of the paper, it is difficult to perform proper printing. Further, in the case where a soft and flexible sheet-like material is baked and solidified, if the sheet-like material has wrinkles, it is difficult to obtain an appropriate baked product. Therefore, it is desirable to inspect for wrinkles of this kind before proceeding to a predetermined processing step.

[0003]

Conventionally, humans have performed this kind of inspection with eyes, but there are variations in the inspection results, and it is difficult to perform high-speed and highly accurate inspection.
For this reason, the advent of an automatic inspection apparatus is desired, but at present, such an apparatus has not been proposed yet.

The present invention has been made in view of the above problems, and an object thereof is to provide an unevenness observing device capable of highly accurately inspecting unevenness such as wrinkles formed on a flat surface to be observed.

[0005]

The present invention is an unevenness observing device for observing unevenness formed on a flat surface of an observation target, which comprises a shield, a light projecting device, and an imaging device. There is. The shield is arranged so as to cover the flat surface of the observation target and to form a minute gap with the flat surface. The light projecting device is arranged outside the shield toward the minute gap, and is capable of irradiating the plate-like light from the minute gap to the inside of the shield in parallel with the flat surface. The imaging device is arranged above the flat surface of the observation target, and is positioned inside the shield with the objective lens facing the flat surface.

Further, in the unevenness observing device according to the invention of claim 2, the inner surface of the shield is a light absorber.

[0007]

[Function] When a plate-like light is applied in parallel to a flat surface having irregularities such as wrinkles covered with a shield, the irregularities are exposed to light and only that portion is illuminated. High-intensity parts appear on the image corresponding to the uneven parts.

In the unevenness observing device according to the second aspect, since the inner surface of the shield is the light absorber, generation of reflected light on the inner surface of the shield is prevented and a clear image can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the appearance of an unevenness observing device 1 according to an embodiment of the present invention. The unevenness observing device 1 is arranged along the conveyance path of the belt conveyor 2 and automatically inspects each inspected product 3 on the belt conveyor 2 for wrinkles. In this embodiment, the inspection object 3 is a sheet-like material such as a piece of paper or a synthetic resin sheet, but it is not limited to this, and not only wrinkles but also undulations and irregularities generated on the surface of the object. It can also be applied to the inspection of.

The unevenness observing device 1 in the illustrated example includes a shield 4, a light projecting device 5, and an image pickup device 6, and the image pickup device 6 is connected to an image processing device 7. The shield 4 is for preventing external illumination light from hitting the flat surface of the inspection object 3, and covers the surface of the inspection object 3 and as shown in FIG. It is arranged right above the belt conveyor 2 so that a minute gap 8 of about 1 to 2 mm is formed between the surface of the belt conveyor 2 and the surface of the belt 3. The inner surface of the shield 4 is a non-reflective surface that absorbs light and does not generate reflected light. This non-reflective surface is formed by applying non-reflective paint to the inner surface of the shield 4 or attaching a non-reflective sheet.

The light projecting device 5 is for irradiating the plate-like light 9 from the minute gap 8 to the inside of the shield 4 in parallel with the surface of the object 3 to be inspected. It is arranged on the outer side toward the minute gap 8. The light projecting device 5 of the illustrated example has a light source such as a halogen lamp or a fluorescent lamp built in a case, one end of the optical fiber 10 is connected to the light source, and the other end is pulled out of the case to face the minute gap 8. It is located.

The minute gap 8 is for guiding only the projection light from the light projecting device 5 to the inside of the shield 4, but in the case of this embodiment, the light emitted from the tip end surface of the optical fiber 10 and spread out. Has a function of squeezing to a thickness corresponding to the minute gap 8 to form the plate-like light 9.

In this embodiment, one optical fiber is used, but in order to widen the width of the plate-shaped light 9, a plurality of optical fibers may be arranged in a line and used. An optical fiber may be used. In addition to forming the plate-shaped light 9 in the minute gap 8, as shown in FIG.
The slit plate 12 may be provided in the vicinity of the light source 11, and the light from the light source 11 may be passed through the slit 13. In this case, the minute gap 8 does not have a function of generating plate light.

The image pickup device 6 is for picking up an image of the surface of the article 3 to be inspected from directly above, and the objective lens 14 is arranged inside the shield 4 so as to face the surface of the article 3 to be inspected. It is positioned. The image obtained by the image pickup device 6 is sent to the image processing device 7 and subjected to preprocessing such as binarization, and then the presence or absence of wrinkles is discriminated from the binary image, and the discrimination result is displayed on the display unit 15. indicate.

Next, the operation of the unevenness observing device 1 having the above structure will be described. Now, when the light projecting device 5 is driven, light is emitted from the tip end surface of the optical fiber 10 and becomes plate-like light 9 through the minute gap 8 and travels inward of the shield 4 in parallel with the surface of the inspection object 3. . If the surface of the inspected product 3 is not wrinkled, the plate-shaped light 9 passes through as it is and does not hit the surface of the inspected product 3. If wrinkles are generated on the surface of the inspected product 3, the plate-shaped light 9 strikes the convex portions 17 and the concave portions 18 of the wrinkles 16 to generate reflected light, as shown in FIG. Become.

When the surface of the product 3 to be inspected is imaged from directly above by the image pickup device 6, the product to be inspected without wrinkles becomes a dark image. On the other hand, the wrinkled product to be inspected has an image in which a high-luminance portion corresponding to the convex portion 17 and the concave portion 18 appears in a dark background. When this image is taken into the image processing device 7 and binarized, as shown in FIG.
The high-luminance portion 20 is a binary image in which white pixels appear and the background portion 21 appears as black pixels.

The image processing apparatus 1 raster-scans the binary image 19, counts the number of white pixels in the binary image 19, and compares the counted value with a predetermined threshold value. If the count value is larger than the threshold value, it is determined that the inspected product 3 is a defective product in which wrinkles have occurred, and if it is less than the threshold value, the inspected product 3 is a non-defective product in which wrinkles have not occurred. The determination result is displayed on the display unit 15.

[0018]

As described above, according to the present invention, the flat surface of the observation target is covered with the shield, and the plate-like light is made parallel to the flat surface from the minute gap between the observation target and the shield to the inside of the shield. By irradiating, the image of the flat surface is picked up by the image pickup device, so that the unevenness such as wrinkles generated on the flat surface of the observation target can be observed as a high-intensity portion, without human intervention, and at high speed. Highly accurate automatic inspection of irregularities is possible.

According to the second aspect of the invention, since the inner surface of the shield is a light absorber, generation of reflected light on the inner surface of the shield can be prevented, and a clear image can be obtained by this inspection. Accuracy is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing the outer appearance of an unevenness observation device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an observation state of unevenness.

FIG. 3 is an explanatory diagram showing a generation state of a high brightness portion.

FIG. 4 is an explanatory diagram showing a binary image including a high-luminance portion.

FIG. 5 is a sectional view showing another embodiment of the light projecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concavo-convex observation device 4 Shield 5 Projector 6 Imager 8 Small gap 14 Objective lens

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G06T 1/00

Claims (2)

[Claims] 1. An unevenness observing device for observing unevenness generated on a flat surface of an observation target, comprising: a shield, a light projecting device, and an imaging device, wherein the shield is a flat surface of the observation target. The light projecting device is arranged so as to cover the surface and to form a minute gap between itself and the flat surface, the light projecting device is arranged outside the shield toward the minute gap, and has a plate shape from the minute gap to the inside of the shield. It is possible to irradiate light in parallel with the flat surface, the imaging device is arranged above the flat surface of the observation target,
An unevenness observing device in which an objective lens is positioned inside a shield so as to face a flat surface. 2. The unevenness observation device according to claim 1, wherein the inner surface of the shield is a light absorber.