JP2003132342A - Image input method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To input the image of a work region by sufficiently increasing the light quantity of lighting, when taking a picture of an inspection object with a work with its transmissivity lower than that of a base material disposed at a prescribed position on the high-transmissivity sheet base material by a line sensor camera under a transmission lighting. SOLUTION: This image input method includes to take a picture of an input object by the camera 12 while the input object W with the work (printing pattern) Wa with its transmissivity lower than that of the base material, disposed at the prescribed position on the high-transmissivity sheet base material (transparent film) S is made to pass between the transmission lighting 10 and the line sensor camera 12. The transmission light passing through the region outside the work positioned on an intersection line where the optical axis of the line sensor camera intersects with the inspection object is cut off by making a light shielding member 16 aligned along the intersection line into the state of 16A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input method and apparatus, and in particular, to a subject to be inspected in which a work having a lower transmittance than the substrate is arranged at a predetermined position of a sheet-shaped substrate having a high transmittance. The present invention relates to an image input method and apparatus suitable for application when inputting an image of a region in a work imaged by the line sensor camera while passing between the line sensor camera and the line sensor camera.

[0002]

2. Description of the Related Art Now, as shown in FIG. 7, which is an image of an object to be inspected, an inspection object such as a printed matter having a pattern printed at a predetermined position on a sheet-like substrate S made of a transparent film. As described above, it is assumed that the inside of the work in the inner region of the work has a very low light transmittance as compared with the outside of the work corresponding to the peripheral region of the work Wa such as a pattern.

Such an inspection object (input object) W
As shown in the image when viewed from the front in FIG. 8A, the line sensor camera 12 positioned above illuminates the range above the width of the workpiece Wa while illuminating the transmitted light source 10 positioned below. Consider the case of imaging as.

When an image is picked up by the line sensor camera 12 in this way, the relationship between the luminance values when the image pickup device 12A of the camera 12 receives the light is made to correspond to the inspection object W of FIG. As shown in FIG. 1B, there is a region having a higher transmittance outside the work than in the work. This is an example of the case where an image is taken under transmitted illumination with a sufficient amount of light, and the boundary part of the work in the input image shows a value higher than the original luminance value shown by the chain double-dashed line, as shown by the circle. Therefore, the dynamic range, which is the range between the maximum value and the minimum value of the brightness value in the work, cannot be widened, so that accurate image input cannot be performed. This phenomenon becomes remarkable when the light amount outside the work exceeds the saturated light amount of the image sensor, as the brightness value is constant at the maximum value of 255 (in the case of 8 bits) in the figure. Therefore, in order to prevent such a phenomenon from occurring, the light amount of the transmitted illumination is set so that the transmitted light amount of the area outside the work is smaller than the saturated light amount of the image pickup element, as shown in FIG. However, the luminance value is set to be smaller than the maximum value of 255 as shown in FIG.

[0005]

However, when the light amount of the transmitted illumination is set to be small as described above, FIG.
As indicated by a circle in (C), the work boundary portion is close to the original brightness value because the influence of the transmitted light amount is small, but the maximum brightness value in the input image is the full range (2
55), the maximum luminance value in the area within the work is reduced to the same extent, and the dynamic range is narrowed. Ideally, a wide dynamic range as shown in FIG. 7B, which corresponds to the two-dot chain line in FIG. 7B, should be ideal. There is a problem that the accuracy is reduced.

The present invention has been made to solve the above-mentioned conventional problems, and provides an inspection object in which a work having a lower transmittance than the substrate is arranged at a predetermined position of a sheet substrate having a high transmittance. An object of the present invention is to provide an image input method and device using a line sensor camera, which can input an image of a work area with a sufficiently large amount of illumination light when capturing an image under transmitted illumination with the line sensor camera.

[0007]

According to the present invention, an inspection object in which a work having a lower transmissivity than the base is arranged at a predetermined position of a sheet-shaped base having a high transmissivity, is provided with a transmission illumination and a line sensor camera. An image input method for capturing an image with the line sensor camera while passing through the space, wherein the illumination light is incident on a region outside the work located on a line of intersection where the optical axis of the line sensor camera intersects the inspection object. Alternatively, the above problem is solved by blocking transmitted light that has passed through the same region.

According to the present invention, an inspection object in which a work having a lower transmissivity than the base is placed at a predetermined position of a sheet-shaped base having a high transmissivity is passed between the transmissive illumination and the line sensor camera. While the image sensor is an image input device that captures an image with the line sensor camera, the illumination light incident on an area outside the work located on an intersection line where the optical axis of the line sensor camera intersects the inspection object or the same area. By providing a light blocking device for blocking the transmitted light that has passed through, the above problem is similarly solved.

That is, according to the present invention, since the line sensor camera is prevented from entering the light from the work outside area which has a bad effect on the brightness of the work boundary portion in the input image due to the high transmittance, the light quantity of the transmitted illumination is reduced. Since it is possible to sufficiently increase the dynamic range in the work area as a result, it is possible to input an image having a sufficiently large density difference from the work area.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1A is a front view showing the outline of an image input apparatus according to an embodiment of the present invention, FIG. 1B is a plan view thereof, and FIG. 1C is a side view thereof.

The image input device of this embodiment is shown in FIG.
As shown in FIG. 3, a printed matter on which a pattern (work) Wa is printed at a predetermined position of a transparent film (sheet-shaped substrate) S that is moved (conveyed) in a direction orthogonal to the paper is set as an inspection object (input object) W. A line-shaped transmissive light source 10 made of a fluorescent lamp is provided below the object W, and a line sensor camera 12 is provided above the object W. It is arranged to be orthogonal to each other.

As shown in FIG. 1B, the inspection object W has a work Wa of a predetermined size, which is a printed pattern,
It is assumed that the transparent film S is multi-faced on the transparent film S at a predetermined interval, the inside of the pattern is inside the work, and the other regions only of the transparent film are outside the work.

The image input device according to the present embodiment includes a light blocking device 1.
As shown in FIG. 1 (C), the light shielding device 14 includes a light shielding member 16 having a predetermined width, which is substantially L-shaped when viewed from the side, but a part thereof is omitted in FIG. However, as shown in FIG.
Two optical axes are juxtaposed along an intersection line K intersecting the inspection object W over a range beyond the visual field of the camera 12.

As shown in FIG. 1C, the light-shielding member 16 has a rotary shaft 18 which is disposed at a portion corresponding to an L-shaped (here, inverted L) vertical line in a direction orthogonal to the carrying direction. Is pivoted around the shaft 18 and is rotated about the shaft 18, so that the light shielding plate of the portion corresponding to the L-shaped horizontal line is in a lowered state 16A where it intersects the optical axis of the line sensor camera 12, and a raised state where it does not intersect. It is possible to switch between two states of the member 16B.

In the present embodiment, in the light shielding device 14, before the line sensor camera 12 captures an image of the inspection object W, the outside of the workpiece of the inspection object W is shielded in a lowered state in which the optical axis is blocked. The member 16A is set, and the light shielding member 16B is set in a raised state so as not to block the optical axis with respect to the inside of the work, and at the time of actual imaging, the arrangement is as shown in the images in FIGS. 1 (A) and 1 (B). Thus, the transmitted light from only the region of the work Wa is incident on the line sensor camera 12.

Next, the characteristics of one light-shielding member 16 constituting the light-shielding device 14 and how to set the inspection object W will be described.

FIG. 2A is an enlarged front view showing the light shielding member 16, and FIG. 2B is a right side view thereof. The light-blocking member 16 is made of a metal that has been subjected to light reflection prevention processing.
As shown in the drawing, the width W corresponding to the juxtaposed direction, the thickness T of the light shielding plate, and the length (depth) D of the light shielding plate are formed.

The thickness T of the shading plate is reduced to a level not affected by the diffraction of light, and the width W is set to a size required for input accuracy. In particular, when it is desired to input the entire region in the work with high accuracy, it is desirable to make the width W as small as possible in order to prevent the light shielding plate from entering the inside of the work.

The depth D of the shading plate is set to a length such that light does not leak above the shading device when all the shading plates are lowered, and the shading plate is a single one where the optical axis of the line sensor camera 12 and the inspection object W intersect. Arrange on the line of intersection so that there are as few gaps as possible.

As concrete dimensions, for example, W = 4 m
m, T = 20 mm and D = 30 mm. However, needless to say, the material is not limited to this size, and the material is not limited to metal.

Further, as in the present embodiment, the above-mentioned light shielding member 1
6 is disposed above the inspection object W, the object W
It is desirable that the height H from the light shielding plate to the light shielding plate and the thickness T thereof be as small as possible. The reason is that, as shown in FIG. 3 for the sake of convenience, a light shielding plate in which a plurality of light shielding members 16 are arranged in a light shielding state is shown by a black rectangle, and when T and H are large as shown in FIG. The left side is the work (design) Wa, and A
If the right side of the point is a transparent film outside the work,
The field of view AB at the left end of the lens of the line sensor camera 12 is widened, and light is incident from a region on the right side of the point A having a high transmittance, so that the light shielding device 14 does not play its role. On the other hand, if both T and H are made smaller as shown in FIG. 6B, the same field of view becomes AB ′, which is very narrow, and the light shielding device 14 can be effectively operated. Although it is preferable that the thickness T is thin, it is preferably thicker than 1 mm in order to prevent light diffraction as described above.

When a large number of light-shielding members 16 are arranged side by side in the width direction of the inspection object W as described above, as shown by the black bar in FIG. It is effective that the lines are densely arranged so as not to have a gap over a range (not shown) and a range wider than the field of view of the line sensor camera 12.

As described above, in the present embodiment, as shown in FIG. 1, the line sensor camera 12 is made incident on the large number of light shielding members 16 constituting the light shielding device 14 in the area outside the work. Since the light blocking member 16A is configured to block the transmitted light, and the operator manually rotates the light blocking member 16 upward in the region of the work to be the light blocking member 16B in the state of not blocking the light.
It is possible to shield a region having a higher transmittance than the work region by a simple method without contacting the work with the work.

Therefore, FIG. 5 shows the conventional method, FIG. 6 shows the method of the present invention, (A) shows the characteristics of the image input method, and (B) shows the image received by the line sensor camera 12 when the image is input. Further, as shown in the width direction distribution of the brightness values corresponding to FIG. 8B corresponding to the work Wa, the present embodiment can block the incident light from the outside of the work, so that the illumination Since the amount of light can be set sufficiently large, the dynamic range can be widened. As a result, it is possible to input an image in the work area with a sufficient density difference and with high accuracy.

Further, according to the present embodiment, the operator rotates the light shielding member 16 even when a plurality of types of inspection objects having different width dimensions and intervals of the workpieces attached in the width direction are input as images. It is possible to easily shield the outside of the work by simply responding to any work.

Although the present invention has been specifically described above, the present invention is not limited to the one shown in the above embodiment, and various modifications can be made without departing from the scope of the invention.

For example, in the above embodiment, the light shielding member 16
Although the case of manually operating is shown, the light-shielding member 1 at the corresponding position is automatically specified by designating the range where light is not shielded.
The 6 may rotate upward or downward.

Further, although the case where the light shielding device 14 is arranged above the inspection object W to block the transmitted light is shown, the manual operation becomes difficult, but it is arranged below so as to block the illumination light. You may

Also, an example has been shown in which the light shielding member 16 rotates about the rotation shaft 18, but the invention is not limited to this, and a mechanism for advancing and retracting the light shielding plate with respect to the optical axis position is adopted. You may do it.

[0031]

As described above, according to the present invention,
When a line sensor camera takes an image of an inspection object in which a work having a lower transmittance than that of a sheet-shaped substrate having a high transmittance is arranged at a predetermined position, the amount of illumination light is set sufficiently large. The work area can be input as an image.

[Brief description of drawings]

FIG. 1 is a front view, a plan view, and a side view showing an outline of an image input device according to an embodiment of the invention.

2A and 2B are a front view and a side view showing the features of a light shielding member that constitutes the light shielding device.

FIG. 3 is an explanatory diagram showing a relationship between a light blocking member and a light blocking range.

FIG. 4 is an explanatory view showing an installation range of a light shielding device.

FIG. 5 is an explanatory diagram showing the features of a conventional image input method.

FIG. 6 is an explanatory diagram showing the features of the image input method according to the present invention.

FIG. 7 is a partial plan view showing characteristics of an inspection object.

FIG. 8 is an explanatory diagram showing conventional problems.

[Explanation of symbols]

10 ... Transmitted light source 12 ... Line sensor camera 14 ... Shading device 16 ... Light blocking member 18 ... Rotation axis W ... Inspection object Wa ... Design (work) S ... Transparent film (sheet-like substrate)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Okazawa             1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo             Dai Nippon Printing Co., Ltd. F-term (reference) 2G051 AA01 AA90 AB01 AB02 CA04                       CB02 CC20 DA06 EA16 EA24                 5B047 BA01 BB02 BC11 BC15 BC30                 5C072 AA01 CA02 DA15 EA10 LA12                       LA20 VA03

Claims (5)

[Claims] 1. A sheet-shaped substrate having a high transmittance at a predetermined position,
An image input method for picking up an image of an object to be inspected, on which a work having a transmittance lower than that of the base body, is passed between the transmission illumination and the line sensor camera, the line sensor camera. The image input method is characterized in that illumination light incident on a region outside the work located on an intersection line of which the optical axis intersects with the inspection object or transmitted light passing through the region is blocked. 2. The image input method according to claim 1, wherein the illumination light or the transmitted light is blocked by arranging a light shielding plate having a predetermined width on the intersection line. 3. A sheet-shaped substrate having a high transmittance at a predetermined position,
An image input device for picking up an image of an object to be inspected, on which a work having a transmittance lower than that of the substrate is arranged, between the transmission illumination and the line sensor camera, the line sensor camera. 2. An image input device, comprising: a light-shielding device that blocks illumination light incident on a region outside the work located on a line of intersection where the optical axis of the item intersects with the inspection object or transmitted light passing through the region. 4. The light-shielding device has a structure in which light-shielding members that can switch a light-shielding plate between a light-shielding state that intersects with the optical axis and a non-light-shielding state that does not intersect are arranged in parallel along the intersection line. The image input device according to claim 3, wherein: 5. The light shielding member is axially inserted into a rotating shaft arranged in the intersecting line direction, and is rotated about the rotating shaft to bring the light shielding plate into a light shielding state and a non-light shielding state. The image input device according to claim 4, wherein the image input device is switchable.