JPS60181879A - Photoelectric converting device - Google Patents

Abstract

PURPOSE:To perform efficient and inexpensive detection of surface conditions on an object by irradiating parallel light at a prescribed angle from an oblique direction with respect to the object surface, and equalizing a light irradiation angle at least on the surface to be detected. CONSTITUTION:A device turns light into parallel light by an optical system 13 consisting of an extinction filter 11 and a parallel light lens 12 from a light source 2, irradiates the parallel light at the prescribed angle from an oblique direction on a flap side with respect to the reverse surface of a mail P, and projects the reflected light on the light receiving surface of a line sensor 4 by a projecting lens 3 and then performs photoelectric conversion. By irradiating the parallel light at the prescribed angle from said direction on the flap side with respect to said P, the irradiating angle will become equal (theta) at any position on the P, by which a shade S produced by a difference in level of the flap 1 is generated regardless of the shape and location of the flap, thereby enabling secure flap detection over the upper/lower directional wide range of the P.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a photoelectric sensor used for detecting flaps of mail, for example, in a mail automatic cancellation and stamping machine that aligns and stamps the front and back, top and bottom of mail. This invention relates to a conversion device.

[Technical Background of the Invention] For example, as is well known, an automatic postal item cancellation and stamping machine stamps the front and back of supplied mail items, as well as the top and bottom sides thereof. In that case, it is necessary to determine the front and back sides of the mail item, as well as the top and bottom directions.
In the case of a postal item P having a flap 1, the flap 1 may be detected and the detected information may be used as one of the determination factors.

A conventional photoelectric conversion device used for such flap detection is shown in FIG. 2.

That is, light from a light source 2 such as a halogen lamp is directed at the surface of the mail P having the flap 1 (that is, the back surface) from an oblique direction on the flap side, and the reflected light is #a (
The i-lens 3 forms an image on the light-receiving surface of the line sensor 4 and performs photoelectric conversion to detect the shadow S caused by the step of the flap 1. In this case, Linesen 4
) 4 is the direction of arrow a shown in FIG.
The output signal of the line sensor 4 is as shown in FIG. 3, where F is a flap signal due to the shadow S caused by the step of the flap 1. Then, by quantizing the output signal of the line sensor 4 using a predetermined slice signal L1, flap detection information is obtained.

[Background Art WjO Problems] However, the above-mentioned conventional photoelectric conversion device has the following problems. That is, in the conventional illumination method, θ1. θ2. As shown by θyo, θ4° and θ5, the angle of illumination of the light differs depending on the position on the mail P. In other words, the closer the light source 2 is, the larger the irradiation angle becomes. However, there are various shapes of the flap 1 of the postal item P, and while there is no problem with relatively large-shaped flaps, for example, relatively small-shaped flaps such as the one shown by the broken line in FIG. In this case (when the flap 1 is located relatively above the mail P), the flap 1 exists on the side where the irradiation angle is large.

In this case, the shadow S caused by the step of the flap 1 hardly occurs (even if it occurs, it is a very small shadow), and as a result, it becomes undetectable. Even if it were detected, the level of the flap signal F would be so low that it would not only be impossible to distinguish it from noise, but also impossible to quantize.

This becomes more noticeable as the flap 1 is positioned above the mail P.

In addition, conventional methods used to detect the surface roughness of iron plates, plywood, and other flat plates, not just mail items, use microscopes or
Rays, electron beams, ultrasonic waves, etc. are used, but these have the disadvantage of being very expensive, and although they are used to inspect invisible processing conditions, Not suitable for surface inspection.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to provide a photoelectric conversion device that can efficiently detect the surface condition of an object at low cost. When used to detect the flaps of objects, it is an object of the present invention to provide a photoelectric conversion device that can reliably detect flaps over a wide range of the surface of mail objects.

[Summary of light intensity] In order to achieve the above object, the present invention irradiates parallel light at a predetermined angle from an oblique direction with respect to the surface of an object, so that at least the surface to be detected on the surface of the object is illuminated. J
The irradiation angles of the light beams are made equal.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 2 will be described with the same reference numerals as I. In FIG. 4, light from two light sources is converted into parallel light by an optical system 13 consisting of a neutral density filter 11 and a parallel light lens 12, and the parallel light is directed diagonally toward the flap side with respect to the back surface of the mail P. q1 from the line sensor 4 at a predetermined angle, the reflected light is imaged on the light receiving surface of the line sensor 4 by the imaging lens 3, and is photoelectrically converted. The above-mentioned neutral density filter 11 is for correcting the difference in light amount on the irradiated surface (the back surface of the mail P), and has the characteristic (attenuation proportional to the light unevenness above and below the mail P) as shown in FIG. For example, as shown in the cross-sectional view in FIG. This can be achieved by adding vapor@1!15 which increases the light transmittance. Further, a cylindrical lens 16 is provided in front of the irradiation surface to correct a loss due to a decrease in the light amount of the neutral density filter 11.

Therefore, the output signal of the line sensor 4 is transmitted to the quantization circuit 17.
and is quantized by a predetermined slice signal L2 set by a variable resistor 18.

With such a configuration, by irradiating the back surface of the postal item P with parallel light at a predetermined angle from an oblique direction on the C flap side, the irradiation angle of the light is the same at any position on the postal item P (θ )Become. As a result, no matter what shape the flap 1 has or where the flap 1 is located, the shadow S on the step of the flap 1 is reliably produced.

Therefore, flap detection can be reliably performed over a wide range in the vertical direction of the mail P.

Further, the light attenuation filter 11 corrects the difference in light amount on the irradiated surface of the mail P by the action of the light attenuation filter 11, and the light amount is uniformly 1q on the irradiated surface. It is possible to alleviate the decrease in the amount of light caused by this, and the amount of light can be reduced by 19 times, which is approximately Jtl fi compared to the conventional method. As a result, a horizontal output signal free from shading caused by light unevenness as shown in FIG. A flap quantized signal as shown in Figure (b) is 1q. In this way, by installing the light attenuation filter 11 and the cylindrical lens 16, a photoelectric conversion signal without shading caused by light unevenness can be obtained from the line sensor 4. Thereby, the output signal of the line lens 4 can be reliably quantized using a simple slice method (DC slice signal). Note that if the neutral density filter 11 is not provided, the parallel light is irradiated from an oblique direction, so the upper part of the mail P (the part near the light source 2) in FIG.
(the part far from the light source) becomes dark, and as a result, the output signal of the line sensor 4 also has a signal waveform that slopes upward to the right with respect to the drawing, as shown in FIG. That is,
This results in a signal with a shading phenomenon due to uneven light. There are various problems in quantizing such signals, such as the fact that it is very difficult to quantize them using a simple slice method (for example, a DC slice signal). Therefore, in the present invention, such a problem is removed by providing the above-mentioned dark filter 11.

In the actual example described above, a case was described in which a flap of a mail piece is detected, but the present invention is not limited to this, and can be used, for example, with paper or a metal plate.

The same idea can be applied to detecting wrinkles that occur on flat plates such as plywood.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a photoelectric conversion device that can easily and efficiently detect the surface condition of an object. When used in □, it is possible to provide a photoelectric conversion device that can reliably perform flap detection over a wide range of the surface of mail.

[Brief explanation of the drawing]

Figure 1 shows an example of a mail item with a flap, Figure 2 shows an example of a mail item with a flap.
The figure is a block diagram showing a conventional photoelectric conversion device, FIG. 3 is a waveform diagram showing the output signal of the line sensor in FIG. 2, and FIGS. Figure 4 is an overall configuration diagram, Figure 5 is a characteristic diagram of the neutral density filter, Figure 6 is a diagram of the configuration of the neutral density filter, and Figures 7 and 8 are signals for explaining the operation. FIG. P... Mail, 1... Flap, 2... Light source, 3
... Imaging lens', 4... Line lens (photoelectric converter), 11... Neutral density filter, 12... Parallel light lens, 13... Optical system, 16... Cylindrical lens, 17 ...Quantization circuit. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 a Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (5)

[Claims] (1) A light source that emits light obliquely at a predetermined angle to the detection surface of an object, and an optical system that converts the light that is directed from this light source onto the detection surface into flat 1J light. A photoelectric conversion device comprising: a photoelectric conversion system; and a photoelectric converter that receives reflected light from the detection surface and converts it into an electrical signal. (2) The detection surface is a surface having a flap of mail,
The photoelectric conversion device according to claim 1, which detects the shadow of the flap. (3) The optical system includes a lens that converts light from a light source into parallel light, and a neutral density filter that corrects a difference in light amount on a detection surface. photoelectric conversion device. (4) The photoelectric conversion device according to claim 3, further comprising a cylindrical lens provided in front of the detection surface for correcting loss due to a decrease in light intensity of the neutral density filter. (5) The photoelectric conversion device according to claim 1, wherein the photoelectric converter is a line sensor.