JPH06288903A - Light transmission detector for inspecting internal quality of vegetables and fruits - Google Patents

Abstract

PURPOSE:To reduce power energy as compared with a case using a single light source and to simply constitute an illumination optical system by illuminating vegetables and fruits using a plurality of light sources. CONSTITUTION:Halogen lamps 4 being a plurality of light sources irradiate vegetables and fruits 20 transferred to a measuring stage with illumination light. Heat rays cutting filters 5 are arranged in front of the lamps 4 to make infrared rays unnecessary for measurement impermeable so as not to damage vegetables and fruits 20. A suction pad 6 is connected to a vacuum pump 7 through a suction pipe 8 and comes into contact with the vegetables and fruits 20 to suck each of them and the contact part thereof is hermetically sealed. By this constitution, it is prevented that disturbance light enters a next receiving optical system. Further, an optical fiber 9 is arranged in the pad 6 and one end thereof is opposed to each of the vegetables and fruits 20 in the pad 6 and the other end thereof is connected to a spectroscope 10. By this constitution, the quantity of illumination light is increased using a plurality of the light sources and an increase in power energy can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light transmission detecting device used for inspecting and measuring fruits and vegetables, and more specifically, it is useful for nondestructively inspecting and measuring the internal quality of fruits and vegetables. The present invention relates to a light transmission detection device that can suitably obtain transmitted light.

In the present specification, the term "fruit and fruit" or "fruit" includes both fruits and vegetables.

[0003]

BACKGROUND OF THE INVENTION As is well known, the trading price of fruits and vegetables in the trading market is greatly influenced by its quality. For example, the variety and the place of origin have been used as one of the quality indicators from the past, and the appearance such as the size and shape of each fruit and the presence of scratches, etc., as is often done in many sorting fields. Quality is also regarded as a quality indicator. The latter quality index is generally specifically evaluated by rank and grade. This ranking is evaluated because the fruits and vegetables are agricultural products that are affected by the climate and weather under the natural environment, so it is unlikely that the manufactured products will be manufactured with almost no quality difference between products with the same standard. Differently, even for a single variety of fruits and vegetables shipped from a certain region, the evaluation of individual fruits varies greatly depending on the size, shape, appearance quality, etc., which directly affects the transaction price. Is.

[0004] As described above, the quality evaluation of fruits and vegetables is based on the evaluation of the whole of a specific group based on the above-mentioned varieties and the like, and, apart from this, the appearance quality such as the presence or absence of scratches on individual fruits in the group. It was conducted by comprehensively evaluating individual representative fruits.

Recently, however, a technique (non-destructive inspection technique) for inspecting / measuring internal qualities such as the sugar content of peaches and the presence or absence of nests in watermelons has been proposed. In addition, since these internal qualities are extremely important indicators for consumers to purchase products, it is desired to apply the internal quality inspection / measurement technology to practical use. For example, if the peach that you purchased because you thought it was sweet is not really sweet, consumers will feel that you have lost significantly, and dealers and producers are at a greater risk of losing credit. . Examples of internal quality of such fruits and vegetables include sugar content, acidity, astringency, values of chlorophyll, etc., presence or absence of diseases / disorders represented by browning, mitosis, nuclear cracking, and the like. Similar to the above-mentioned appearance quality, it is not uniform in each fruit.

[0006] Under the above-mentioned background, the techniques conventionally proposed as the technique for inspecting the internal quality of fruits and vegetables are as follows.
There is a reflected light optical measurement method in which fruits and vegetables are illuminated with light and the sugar content is measured by spectroscopic analysis of the reflected light. However, since this reflected light method can measure at most the internal quality near the epidermis of the fruit, it has not been widely used. Therefore, instead of this, it is conceivable to measure the internal quality by the light transmitted through the fruit.

However, there are some problems to be solved in order to be able to inspect and measure the internal quality of fruits of fruits and vegetables to a certain degree of practical use by this transmitted light method.

One of the problems is that the attenuation of transmitted light is extremely large in many fruits and vegetables. For example, in Satsuma mandarin, the decay rate is 10 ^-4 to 10 ^-6 , and in apples, the value is even larger, from 10 ^-6 to 10 ^-8 , so the amount of light emitted from the light source to the fruits and vegetables is relatively large. Also,
This is because the amount of transmitted light to be analyzed becomes extremely weak, the measurement accuracy is lowered, and the reliability of the measurement result becomes a practical problem as it is.

As a measure against such a problem of high attenuation of transmitted light, for example, a powerful lamp may be used to increase the light amount of the light source light, or a method of increasing the light receiving sensitivity on the light receiving side. , Increasing the amount of light from the light source causes the problem of heat generation and power consumption of the lamp,
In addition, the lamp also becomes larger. For this reason, there is no suitable lighting lamp that can be actually used as an apparatus for inspecting the internal quality of fruits and vegetables. As the latter method of increasing the light receiving sensitivity, it is conceivable to increase the light receiving area of the light receiving element or to multiply the light intensity received by using a photomultiplier tube, an image intensifier, etc. However, the enlargement of the cooling system increases the size of the cooling device for removing the noise component, and causes the problem of reduced accuracy due to unevenness of the optical system. Further, the photomultiplier tube and the like are included in the received light in principle. Since the frequency-dependent information disappears and only the light intensity is proportionally multiplied, it becomes unsuitable for measuring the internal quality of the multiplied optical information. Therefore, there is a fatal problem that the sugar content cannot be measured using the degree of absorption of light in a specific wavelength range. Thus, conventionally, the internal quality of fruits and vegetables has been inspected by transmitted light.
There was no technically satisfactory measurement on either the illumination side or the light receiving side.

[0010]

DISCLOSURE OF THE INVENTION The present inventor diligently studied the problem in the case of inspecting / measuring the internal quality of fruits and vegetables by the above-described transmitted light method, and not simply increasing the light amount of the light source. In other words, the present invention was made by studying a method of a transmitted light method that can more efficiently obtain the amount of transmitted light, and can illuminate and detect light with high sensitivity. One of them is to provide a light transmission detecting device which can realize such a method.

Another object of the present invention is to: That is, in order to accurately measure and inspect the internal quality of the fruit based on the transmitted light, the detected transmitted light must have information corresponding to the internal state of the fruit, in addition to the above problem of attenuation of the transmitted light. Is required. However, if the transmitted light optical path inside the fruit is biased due to uneven illumination or the like, it means that the measurement result does not accurately represent the actual internal quality.

From this point of view, the present inventor can detect transmitted light having information that matches (correspond to) the actual internal state of the fruit as much as possible, in addition to realizing transmitted light detection with high sensitivity. The present invention has been accomplished for the purpose of providing a light transmission detecting device devised in this way.

[0013]

The features of the present invention made to realize the above objects are as set forth in each claim of the above claims.

Further, one of the features of the light transmission detecting device according to the present invention is that the light receiving means facing a part of the surface of the fruits and vegetables so as to receive the transmitted light emitted from the fruits and vegetables, and the transmitted light to the light receiving means. Except for the light-shielding means arranged at the position where the fruits and vegetables and the light-receiving means face each other so as to prevent the outside light other than the above from entering, and the arrangement positions of these light-receiving means and light-shielding means by the illumination light from a plurality of light-emitting sources And an illumination optical system provided to illuminate the fruits and vegetables from around the fruits and vegetables.

The transmitted light received by the light receiving optical system of the light transmission detecting device is not particularly limited, but is guided to a spectroscope through an optical fiber which is a light receiving means facing the fruit and vegetables, and has a predetermined wavelength. CC of light intensity for each band
It can be used for inspecting the internal quality by performing spectroscopic analysis detected by D or the like and measuring the sugar content based on the degree of absorption in a predetermined wavelength range.

The light transmission detecting device of the present invention comprises:
By configuring the illumination optical system using multiple light sources,
A higher light quantity can be obtained with the same power as the illumination optical system of the single light emitting source. This can be confirmed from the result of FIG. 4 which compares the amount of emitted light when the same power energy is supplied to the total of the single light source lamp and the two light source lamps. As the plurality of light emitting sources, a plurality of light source lamps of the same standard such as a halogen lamp can be used, and if necessary, light source lamps having different light emission amounts or different types of light source lamps may be used in combination. Further, the number of light emitting light sources may be changed according to the shape of fruits and vegetables and the difference in the attenuation rate of the transmitted light amount depending on the item.

Further, in the apparatus of the present invention, since the fruits and vegetables are illuminated from the surroundings by the plurality of light sources, the optical path of the transmitted light is suppressed from being biased inside the fruit, and the transmitted light with less unevenness can be obtained. Therefore, the measurement result obtained by analyzing the obtained transmitted light sufficiently reflects the actual internal state of the fruit. It is effective to use at least two light sources, but it is preferable to evenly arrange three or more light sources around the fruits and vegetables in order to illuminate spherical fruits such as peaches and apples evenly. In this way, if a single powerful light source lamp is used when multiple light emitting sources are used, it is necessary to separate the light source from the fruits and vegetables with a lens system etc. as much as possible in consideration of its heat generation. Since the calorific value of can be significantly reduced, it is also possible to directly arrange the lamps around the fruits and vegetables so that the structure of the device can be simplified.

The light-shielding means used in the above-mentioned device of the present invention is not particularly limited, but for example, a perforated elastic member having a hole in the central portion and having a shape in which fruits and vegetables are placed so as to cover the hole. A sheet can be preferably used. That is, when the fruits and vegetables are placed on the perforated elastic sheet, the lower side of the holes is in a dark place surrounded by a suitable light shielding member, and the light receiving means facing the fruits and vegetables is arranged in this dark place. It is easy to do.

Further, for the quality inspection of fruits and vegetables, it is generally desirable to adopt a method in which the fruits and vegetables are temporarily stopped or continuously moved by an inspection stage provided on the way while being moved by a conveyor. In such a case, a method in which fruits and vegetables are placed on individual trays and conveyed is preferably used. That is, if each of the trays is configured to have a vertical through hole and the perforated elastic sheet is provided so as to close the through hole of the tray, the light shielding means by the elastic sheet also serves as a sheet for preventing damage to fruits and vegetables. This is because it can be configured.

Further, as a structure for receiving the transmitted light from the illuminated fruits and vegetables as efficiently as possible, the leakage of the transmitted light from the surface of the fruits and vegetables excluding the illumination portion and the light receiving portion is suppressed. It is also preferable that the surface of the portion of the fruits and vegetables is covered with a light shielding member for this purpose. Specifically, the amount of light received by the light receiving optical system can be increased by pressing a soft member such as a sponge or a soft elastic roll against the surface of the fruit and vegetables. When using a soft roll, illumination and light reception can be performed while moving fruits and vegetables.

Apart from the above, another feature of the light transmission detecting device of the present invention is that the light from a plurality of light emitting sources is
An illumination optical system that irradiates fruits and vegetables through a path that is blocked so that outside light does not enter, a light-receiving optical system having a light-receiving means that faces the fruits and vegetables so as to receive the transmitted light emitted from the fruits and vegetables, and this light-receiving optical system. A photoelectric conversion means for converting an optical signal received by the system into an electric signal; and a transmitted light signal component detecting means for detecting a signal component of transmitted light included in the electric signal and removing a signal component of ambient light. As a means for removing the disturbance light component, the chopping means for intermittently turning on and off the illumination light provided in the illumination optical system and the frequency of the chopping means are provided as means for removing the disturbance light component. As the reference signal (standard signal), an example in which a synchronous signal such as a lock-in amplifier that detects a signal component of transmitted light is combined with an electric signal photoelectrically converted by a light receiving system can be exemplified. Since the ambient light generally has a frequency of commercial AC (50 cycles, 60 cycles), the light source is driven to be lit by an AC power source having a frequency different from the commercial AC, instead of the chopping means, and the lighting drive is performed. Even if the frequency of the AC power source is used as the reference signal of the synchronizing circuit, the signal component of the transmitted light can be detected.

According to such a configuration, even if the ambient light enters the light receiving optical system, only the signal component derived from the transmitted light can be taken out, so that the configuration of the optical system can be simplified. Further, if an image of fruits and vegetables is captured by using an image pickup camera (for example, a spectroscopic camera) in the light receiving optical system, a more detailed inspection of internal quality can be realized.

When using the above-mentioned illumination light which is turned on and off, an appropriate light-shielding means for preventing the illumination light from directly entering the light receiving means without transmitting the fruits and vegetables, for example, the perforated elastic sheet described above. And the like are preferably used in an illumination optical system, and a configuration in which light from a light source is guided to fruits and vegetables by an optical fiber is adopted.

Since the present invention is intended for fruits and vegetables,
It is also recommended as a preferable configuration to provide a heat ray cut filter in the optical path of the illumination optical system for the purpose of minimizing the risk of damaging fruits and vegetables by the illumination light.

[0025]

【Example】

Embodiment 1 FIG. 1 is a diagram showing a schematic configuration of an apparatus according to Embodiment 1 of the present invention, in which 1 is a tray, which has a rectangular flat plastic pedestal shape, and a central portion thereof has fruits and vegetables 2
0 is provided in a slightly recessed shape so that it can be easily placed, and a hole 3 penetrating vertically is provided in the bottom of the recess. Then, the tray 1 is horizontally conveyed by a conveyer (not shown) in the direction indicated by the arrow in the figure.
It is designed to be transported over.

FIG. 1 shows a state in which this tray has been transferred to an internal quality measuring stage provided in the middle of the conveyer conveyor.
Is temporarily stopped for measurement.

A light transmission detecting device having the following configuration is provided on this measuring stage. That is, 4, 4 and 4 are halogen lamps as light emitting light sources arranged above the conveyer conveyor, and the fruits and vegetables 2 transferred to the measuring stage 2
The illumination light is emitted to 0. Also,
Heat ray cut filters 5, 5 and 5 are respectively arranged in front of the plurality of halogen lamps so that infrared rays, which are unnecessary for measurement, are made opaque to prevent heat damage to fruits and vegetables. The halogen lamps 4 are preferably arranged evenly around the fruits and vegetables so that the illumination of the fruits and vegetables can be made as uniform as possible. These constitute the illumination optical system.

The reference numeral 6 designates fruits and vegetables 2 from the lower side of the conveying surface 2 through the through hole 3 of the tray 1 stopped on the measuring stage.
It is a suction pad arranged so as to face the bottom of 0, and in this example, from the standby position shown by the one-dot chain line in the figure,
It is provided so as to be moved up and down by a vertical movement mechanism (not shown) between the measurement positions shown by the solid line in which the fruits and vegetables 20 come into contact. The operation of the up-and-down moving mechanism may be provided so as to perform the measurement by moving up when the tray is stopped by the measuring stage in synchronization with the transfer state of the tray. The suction pad 6 is connected to the vacuum pump 7 via the suction pipe 8 and sucks when the suction pad 6 comes into contact with the fruits and vegetables 20, so that the contact portion is hermetically sealed. This is to prevent ambient light from entering the next light receiving optical system.

Reference numeral 9 denotes an optical fiber as a light receiving means disposed inside the suction pad 6, one end of which is opposed to the fruit and vegetables inside the suction pad 6 and the other end is connected to the spectroscope 10. It goes without saying that the optical fiber 9 is provided so as not to enter light from the outside.
This constitutes the light receiving optical system. The spectroscope 10 has a known structure, for example, by switching a plurality of filters having different transmission frequencies and detecting the light intensity of each wavelength band with a CCD (solid-state image sensor) or the like, a predetermined region (for example, a visible light region It is possible to use, for example, a device that performs spectroscopic analysis in the near infrared region).

According to the light transmission detecting device having the above structure, by illuminating fruits and vegetables using a plurality of light emitting sources,
It has the advantages that the power energy is less than that when a single light source is used, and that the illumination optical system can be easily configured using a commercially available halogen lamp. Further, since a plurality of light emitting sources can be arranged around the fruits and vegetables, it is possible to detect transmitted light having information sufficiently reflecting the internal state without deviating the optical path of light passing through the fruits and vegetables. Can also be obtained.

Example 2 This example shown in FIG. 2 is different from Example 1 described above in that the fruits and vegetables are illuminated with illumination light from a plurality of light emitting sources through a light-shielded path, and the fruits and vegetables are not shaded. The example of the structure which detects the transmitted light of is shown.

That is, in the present example, the easily deformable elastic pad 41 is provided on the surface of the recessed portion of the pedestal-shaped tray 31 similar to that of the first embodiment, and the fruits and vegetables are placed on the elastic pad 41. . Then, the halogen lamps 34, 34, 34
Also, the illumination light from the light source composed of the heat ray cut filters 35, 35, 35 is guided to the through holes 33 of the tray by the optical fibers 36, 36, 36, respectively, and the fruits and vegetables are illuminated from the lower side of the measurement stage through the through holes 33. Is configured. It should be noted that it is preferable to shield the transport surface 32 or the lower portion of the measurement stage so that the illumination light of the illumination optical system configured by these does not leak to the upper side of the transport surface 32.

In the present example, a spectroscopic camera 37 is arranged above the fruits and vegetables on the measuring stage to image the fruits and vegetables,
A plurality of pieces of spectral image information are sent to a computer (not shown) for image processing.

In this example, since the spectroscopic camera 37 does not allow only the transmitted light to enter, the spectroscopic image information taken includes the signal component of the ambient light.
Therefore, the lock-in amplifier 4 that detects the signal component of the transmitted light from the signal obtained by the spectroscopic camera 37 is provided after the spectroscopic camera 37.
0 is provided, and a light chopper 38 that rotates at a constant speed is provided in the middle of the optical path of the illumination optical system to turn the illumination light on and off, and the on / off frequency (for example, 100 Hz) of the light chopper 38 is controlled by the photodiode 39. It is provided so as to detect and input this to the lock-in amplifier 40 as a synchronizing signal (reference signal) to remove the signal component of the ambient light.

By doing so, even if the spectroscopic camera 37 receives light containing noise derived from ambient light,
There is an advantage that an image of fruits and vegetables can be taken while satisfying the advantage of illuminating fruits and vegetables with a plurality of light emission sources because only the signal component derived from transmitted light can be extracted.

Embodiment 3 This embodiment shown in FIG. 3 shows a modification of Embodiment 1. In this embodiment, a soft perforated elastic sheet is provided on the entire upper portion of the tray 61 which is substantially the same as that of Embodiment 1. 72 is covered, and the fruits and vegetables 20 are placed on the elastic sheet 72. 73 is a hole of the elastic sheet.

Then, a soft pressing roller 74 such as a sponge is pressed onto the fruits and vegetables 20 to push the fruits and vegetables 20 downward, whereby the fruits and vegetables and the elastic sheet 72 are pressed.
To prevent light from leaking, and by pressing the pressing roller 74, to suppress the transmitted light from the upper portion of the fruit and vegetables so that the amount of the transmitted light emitted from the hole 73 of the elastic sheet 72 is increased as much as possible. Has been devised.
It is preferable that the pressing roller 74 be provided so as to rotate in synchronization with the tray transportation.

Reference numerals 64 and 64 are a plurality of light source lamps arranged on the sides of the fruits and vegetables, and 65 and 65 are heat ray cut filters. These are, for example, in the lateral direction from the conveyance path so as not to disturb the conveyance of the fruits and vegetables. It is good that they are arranged separately. Reference numeral 69 is an optical fiber as a light receiving means arranged so that one end thereof faces the fruit and vegetables through the through hole 63 of the tray and the hole 73 of the elastic sheet, and the other end thereof is connected to the spectroscope 70. The light receiving optical system configured is substantially the same as the configuration of the first embodiment.

In this example, the fruit and vegetable pressing roller 7 is used.
Since it is pushed down at 4, the adhesiveness between the elastic sheet and the fruits and vegetables is enhanced by this, and thus there is an advantage that the vacuum pump for suction as in the first embodiment can be eliminated.
Further, with such a pressing structure, even if the shape of the fruits and vegetables is not spherical and is not constant, sufficient adhesion can be secured, and there is an advantage that there is almost no risk of ambient light entering the light receiving optical system. .

[0040]

According to the transmitted light detecting apparatus of the present invention, the illumination light amount is increased by using a plurality of light emission sources, so that the light amount is increased compared to the case where a powerful lamp is simply used as a single light source. There is an effect that an increase in electric power energy can be reduced and an existing or commercially available halogen lamp having a small light emission amount can be used.

Further, since the amount of heat generated by the light source can be suppressed, the light source can be disposed directly opposite to the fruit or vegetables at the measurement position, and the peripheral structure can be simplified.

Further, since a plurality of illumination light sources can be arranged evenly around the fruits and vegetables, there is no illumination unevenness, and the transmitted light optical paths inside the fruits can be made uniform as a whole. There is also an effect that the light is obtained as information containing information sufficiently reflecting the actual internal quality.

Further, by using a perforated tray having a hole in the center thereof and placing fruits and vegetables on the tray, and receiving light (or illuminating) from the hole, it is possible to easily shield disturbance light from being mixed. There is also an effect that you can.

Furthermore, if the tray is used for carrying fruits and vegetables and an elastic sheet is provided on this tray, this elastic sheet can be used as both a light shield and a damage preventing agent for fruits and vegetables.

Furthermore, even when an image is taken by a spectroscope or a spectroscopic camera without performing light shielding, the frequency included in the illumination light in the illumination optical system is used as a reference signal, and the disturbance light signal is generated in the synchronizing circuit of the light receiving system. If the components are removed, for example, it is possible to capture an image of fruits and vegetables with an imaging camera (for example, a spectroscopic camera) and realize a more detailed inspection of the internal quality.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration outline of a first embodiment of a light transmission detecting device according to the present invention,

FIG. 2 is a diagram showing a schematic configuration of a second embodiment of a light transmission detecting device according to the present invention,

FIG. 3 is a diagram showing a configuration outline of a third embodiment of a light transmission detecting device according to the present invention,

FIG. 4 is a diagram illustrating a difference in light emission amount between a single light emitting light source and a plurality of light emitting light sources.

[Explanation of symbols]

1 ... Tray, 2 ... Conveying surface, 3 ... Through hole, 4
... Halogen lamp, 5 ... Heat ray cut filter, 6 ... Suction pad, 7 ... Vacuum pump, 8 ...
・ Suction tube, 9 ... Optical fiber, 10 ... Spectrometer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihide Kono 630 Shinokase Town, Hamamatsu City, Shizuoka Prefecture Fruit Nondestructive Quality Research Institute Co., Ltd.

Claims (4)

[Claims] 1. A light receiving optical system having a light receiving means opposed to a part of the surface of the fruit and vegetables so as to receive transmitted light emitted from the fruit and vegetables, and ambient light other than the transmitted light enters the light receiving optical system. The light-shielding means arranged at the position where the fruit and the light-receiving means face each other so as to prevent the An optical transmission detection device for inspecting the internal quality of fruits and vegetables, comprising an illumination optical system for illuminating. 2. An illumination optical system for irradiating fruits and vegetables with light from a plurality of light emission sources through a path shielded so that ambient light does not enter, and an illumination optical system facing the fruits and vegetables so as to receive transmitted light emitted from the fruits and vegetables. A light receiving optical system having a light receiving means, a photoelectric conversion means for converting a received optical signal into an electric signal, and a transmitted light signal component detecting means for detecting a signal component of transmitted light included in the electric signal. An optical transmission detection device for inspecting the internal quality of fruits and vegetables, which is characterized by being provided. 3. The transmitted light signal component detecting means according to claim 2, wherein the light chopping means provided in the illumination optical system and the frequency of the chopping means are used as reference signals,
A light transmission detecting device for inspecting the internal quality of fruits and vegetables, characterized by comprising a combination with a synchronizing circuit for detecting a signal component of transmitted light from an electric signal photoelectrically converted. 4. The method according to any one of claims 1 to 3,
A light transmission detection device for inspecting the internal quality of fruits and vegetables, characterized in that a heat ray cut filter is provided in the optical path of the illumination optical system for fruits and vegetables.