JP4032328B2 - Optical sensor for agricultural products - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical sensor used for sorting crops such as root vegetables and fruits.
[0002]
[Prior art]
In order to distinguish crops such as root vegetables and fruits from foreign substances such as stones and soil clumps, or to select crops based on maturity, internal defects, etc., it is disclosed in JP-A-6-249976, This is known from JP-A-1-216265. The former is a system that uses transmitted light, and projects near-infrared light from a light projecting unit arranged on one side to a subject such as a potato and detects the transmitted light by a light receiving unit arranged on the opposite side. Distinguish between potatoes and stones. The latter is a method that uses diffused light, and projects near-infrared light from a light projecting part on one side to the subject, detects diffused light by a light receiving part placed on the same side, and determines the chemical component from its spectral spectrum. To do.
[0003]
[Problems to be solved by the invention]
In the above-described method using transmitted light, the attenuation of the transmitted light is large when the subject is large, and it is necessary to increase the light output. Also, if the optical axes of the light projecting unit and the light receiving unit are shifted, the reflected light and There was a problem that the influence of the analysis light was increased and the accuracy was lowered.
In the above method using diffused light, in order to block the reflected light on the surface of the subject, the inner and outer duplex optical fibers constituting the light projecting portion and the light receiving portion of the optical sensor are brought into close contact with the surface of the subject, or in the center. There is a problem that the operation becomes troublesome because the light emitting hole is brought into close contact with the subject with an optical sensor having a light receiving portion on the lower surface of the hole or an integrating sphere is used.
[0004]
An object of the present invention is to solve these problems, and an object of the present invention is an optical sensor with high identification accuracy, in which the projection output can be changed depending on the size of the subject. It is an object of the present invention to provide a device that does not require the optical axes of the light-receiving portion and the light-receiving portion to coincide with each other, the optical sensor itself to be in close contact with the subject, or the use of an integrating sphere.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the means adopted by the present invention is that the light projecting part and the light receiving part of the optical sensor are arranged adjacent to one side of the subject, and the light projecting surface of the light projecting part and the light receiving surface of the light receiving part are arranged. The light shielding member is provided between them. The distance from the light emitting surface to the subject is preferably the same as or smaller than the distance from the light receiving surface to the subject. The light blocking member can be a bowl-shaped light blocking plate. Further, when the light projecting portion is a box and the light receiving surface is arranged behind the light projecting surface, the light projecting portion of the box itself becomes a light blocking member.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described based on the optical sensor of the first embodiment shown in the drawings.
As shown in FIG. 1, the light projecting unit 1 and the light receiving unit 2 that are stacked one above the other are separate boxes, each having a light projecting surface 5 and a light receiving surface 6 on one side. The light projecting surface 5 and the light receiving surface 6 face the same direction, but the light projecting surface 5 is in front of the light receiving surface 6, that is, at a position closer to the subject 3.
[0007]
As shown in FIG. 1 and FIG. 2, when a projection A such as visible light, infrared light, or laser light is emitted from the light projecting surface 5 of the light projecting unit 1, if the subject 3 is a crop such as potato, Diffuses inside, and the diffused light diverges from the surface. A part of the light enters the light receiving unit 2 as light reception B.
However, when the subject 3 is a stone, as shown in FIG. 3, the light projection A from the light projecting unit 1 is only reflected on the surface, and no internal light diffusion occurs. Since the reflected light C is blocked by the box light projecting unit 2 that functions as the light blocking member 4 of the light receiving unit 2, the reflected light C hardly reaches the light receiving surface of the light receiving unit 2. Therefore, whether the subject 3 is an agricultural product or a debris can be identified by the amount of light received by the light receiving unit 2.
[0008]
Since this optical sensor is not related to the size of the subject, the light projection output can be reduced. Further, since the light blocking member suppresses the incidence of the reflected light on the subject surface to the light receiving portion, the identification accuracy is greatly improved. Furthermore, since this optical sensor does not need to be in close contact with a subject or use an integrating sphere, the operation is extremely easy and can be manufactured at low cost.
[0009]
【Example】
Second and third embodiments will be described.
In the second embodiment shown in FIG. 4, the light projecting surface 5 of the light projecting unit 1 and the light receiving surface 6 of the light receiving unit 2 are on the same plane, and the light blocking member 4 is provided between the light projecting surface 5 and the light receiving surface 6. A bowl-shaped light shielding plate is provided. The configuration other than the above is exactly the same as in the first embodiment, and a part of the diffused light of the subject 3 due to the projection A enters the light receiving unit 2 from the light receiving surface 6 as the light receiving B, but the reflection on the surface of the subject 3 Most of the light is blocked by the light blocking member 4. As described above, since the influence of the reflected light on the light receiving unit can be ignored, high-precision identification is possible.
[0010]
In the third embodiment shown in FIG. 5, the light projecting unit 1 and the light receiving unit 2 are provided in the same box, and the light projecting surface 5 and the light receiving surface 6 are arranged on one side with a gap therebetween. Between the light projecting surface 5 and the light receiving surface 6, a bowl-shaped light shielding plate is disposed as the light blocking member 4. Other configurations are the same as in the above embodiment, and a part of the diffused light of the subject 3 due to the light projection A enters the light receiving unit 2 from the light receiving surface 6 as the light receiving B, but the reflected light on the surface is the light blocking member 4. Therefore, the reflected light incident on the light receiving surface 6 can be ignored.
[0011]
【The invention's effect】
As described above, the optical sensor of the present invention uses diffused light, and since the light projecting unit and the light receiving unit are located on the same side with respect to the subject, the light projecting output is independent of the size of the subject. It is possible to set to low output.
In addition, the optical sensor of the present invention has a light blocking member that suppresses the incidence of surface reflected light due to light projection from the light projecting surface to the subject between the light projecting surface and the light receiving surface. Unlike the case where a conventional optical sensor is brought into close contact with the subject or the influence of surface reflected light cannot be eliminated without using an integrating sphere, the necessity of bringing the optical sensor into contact with the subject is also integrated. There is no need to use a sphere. Therefore, the optical sensor of the present invention has an excellent effect that it is easy to use, has high identification accuracy, and is inexpensive.
[Brief description of the drawings]
FIG. 1 is a perspective view of a first embodiment of the present invention,
FIG. 2 is a schematic diagram showing the state of the optical sensor when the subject is a crop;
FIG. 3 is a diagram showing a state of an optical sensor when a subject is a debris;
FIG. 4 is a view corresponding to FIG. 1 of the second embodiment;
FIG. 5 is a view corresponding to FIG. 1 of the third embodiment;
[Explanation of symbols]
1: light projecting unit 2: light receiving unit 3: subject 4: light blocking member 5: light projecting surface 6: light receiving surface A: light projecting B: light receiving C: reflected light

Claims (4)

In an optical sensor which is composed of an adjacent box light projecting unit (1) and light receiving unit (2) and is arranged on one side of the subject (3), the light projecting unit emits light (A). The surface (5) is provided on one side of the box, and the light receiving unit is provided with a light receiving surface (6) on which light reception (B) is incident on one side of the box. The light projecting surface and the light receiving surface are substantially in the same direction. A light blocking member (4) provided between the light projecting surface and the light receiving surface is disposed from the light projecting surface so that the optical sensor does not need to be in close contact with the subject. A crop optical sensor characterized by suppressing the incidence of surface reflected light (C) on the light-receiving surface due to the light projection onto the subject) .   The light projecting portion (1) is formed in a box shape, and the distance from the subject (3) to the light projecting surface (5) is smaller than the distance from the light receiving surface (6). Optical sensor for agricultural products.   The light projecting surface (5) and the light receiving surface (6) are arranged on substantially the same plane, and a bowl-shaped light blocking member (4) is provided between the light projecting surface and the light receiving surface. The optical sensor for agricultural products according to claim 1.   The optical sensor for agricultural products according to any one of claims 1 to 3, wherein the light projecting unit (1) and the light receiving unit (2) are formed in an integral box shape.

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