JPH0915142A - Simulated fruit employed in measurement of inner quality of vegetable and fruit, and method for calibrating measuring apparatus employing the same - Google Patents

Abstract

PURPOSE: To calibrate an analyzer conveniently and quickly with high reproducibility without employing an actual sample, e.g., a vegetable or fruit, by employing a simulated object for calibration obtained by filling the gap of a transparent double tube structure with an aqueous solution containing the target substance of an object at a specified concentration. CONSTITUTION: A reflective material is set on the inner tube of a double structure container made of a transparent material, e.g. glass or polyethylene, and filled an aqueous solution of cane sugar having same concentration as a fruit or the like thus obtaining a simulated fruit for which the light transmitted through the aqueous solution and reflected on the reflective material is received. A plurality of sets of simulated fruit, designed to have calibration coefficients identical to those of an objective vegetable, are formed and encapsulated with aqueous solution of cane sugar having different concentration. They are mounted sequentially on a conveyor and the calibration is carried out automatically. Since intricate calibration work using an actual object is not required, the measuring apparatus can be calibrated quickly with high reproducibility.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for calibrating an apparatus for nondestructively measuring the internal quality of fruits and vegetables.

[0002]

2. Description of the Related Art In order to quantitatively grasp the internal properties of fruits and vegetables in a non-destructive manner, near infrared light is projected onto a subject, the reflected light and transmitted light are spectrally analyzed, and sugars, etc. are analyzed from the frequency distribution. It is performed to measure the amount of contained components. In order to analyze such internal components with high accuracy, it is important to properly set the accurate calibration curve (calibration formula) used to calculate the analysis value. Various methods have been proposed for obtaining the equation. For example, various data processing methods and analysis methods for improving the accuracy of the calibration formula are described in "Introduction to Near Infrared Spectroscopy" by Iwamoto et al. (Koshobo), pp. 54-93.

By the way, even if a correct calibration formula can be obtained by the above-described method, this formula must be regularly reviewed mainly due to hardware reasons such as changes in the apparatus over time. Such hardware problems mainly include the following: Deviation of the wavelength of the spectroscopic section in the measuring device Change of the color temperature of the light source section over time Change over time due to deterioration of the light receiving element, etc. Electric amplification section Change over time

With respect to the above, a model in which a wavelength standard is installed in a measuring device has also been developed (for example, "Conditions for successful near-infrared analysis" of the 10th non-destructive measurement symposium lecture abstract). Further, as a measure against-, calibration by a reflection or transmission standard body (reference) is generally performed. For example, Japanese Patent Laid-Open No. 5-142036 and Japanese Patent Laid-Open No. 6-25 have incorporated a reference in the apparatus.
8225, JP-A-4-115142, and JP-A-4-116.
503 and JP-A-1-284758.

In all of these conventional techniques, the reference of an inorganic substance is used to optically and electrically calibrate the measuring device to eliminate the influence of the aging of the device. However, even if you calibrate the device and use the correct calibration formula as described above,
The original signal (for example, an absorption spectrum) handled when performing internal content analysis of a subject is extremely weak, and it is difficult to expect accurate measurement over a long period of time. Therefore, in order to guarantee the quality of the products whose components have been measured, it is inevitable to carry out regular tests using actual samples. However, the calibration using real samples (particularly fruits and vegetables) has the following problems. Difficult to secure samples (due to limited availability, samples with multiple different component values are required at the same time). The hassle of manually measuring the component values of a sample. Possible errors in manual analysis of samples (analysis errors, errors resulting from non-uniformity of components in the sample). To determine the calibration value from the result of manual analysis of the sample,
Calibration takes time.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and does not require calibration of an apparatus for nondestructively measuring internal components of fruits and vegetables by a real sample. The purpose is to carry out the procedure easily and quickly with good reproducibility.

[0007]

Means for Solving the Problems The above-mentioned object of the present application is for calibration, which has a characteristic optically similar to that of a fruit or vegetable as a test subject and generates a spectroscopic measurement value corresponding to the concentration of a predetermined target substance component in advance. This is accomplished by calibrating the instrument with more than one standard pseudo sample.

[0008]

EXAMPLE FIG. 1 is a schematic diagram comparing the structure of a fruit with the internal structures of two types of simulated fruit according to the present invention.

(A) shows the actual fruit structure, and the flesh under the epidermis has a structure in which a network structure of cellulose or the like is permeated with an aqueous solution of water, sugar, organic matter or the like. (B) is a first embodiment of the simulated fruit according to the present invention, which is intended to realize optical characteristics similar to the internal structure of the actual fruit. Fill the inside of the container made of transparent material such as glass and polyethylene with colloidal solution of milk, paint, cellulose, etc., add sucrose at the same concentration as the fruit, and make it equivalent to the fruit. To generate a reflection spectrum of. As described above, since the optical characteristics of the present example are similar to those of the fruit, accurate calibration can be expected, but it is difficult to create an appropriate dispersoid, and deterioration or precipitation due to aging occurs. There is a side that is easy to do. (C) is an example in which a transparent material such as glass or polyethylene has a double-tube structure, in which a reflecting material is provided on the inner tube, and a sucrose aqueous solution having a concentration similar to that of fruit is transmitted and reflected by the reflecting material. It is an embodiment of a type that receives the emitted light. The composition of the reflection spectrum is different from that of the fruit, because the aqueous solution contains only the target substance, but there is little risk of aging or deterioration of the aqueous solution.

The fruit sugar content calibration formula in this measuring apparatus is as follows. C_BX = Af1 · F (λ1, λ2, ... λn) + Bf1 Equation 1 where C_BX: measured sugar content F (λ1, λ2, ... λn): absorption data of measurement samples at a plurality of wavelengths Formed sugar content calculation functions Af1, Bf1: Constant (calibration coefficient) In the test using actual fruits, which is usually performed, the correlation diagram between the actual analysis value manually performed and the measurement value calculated by Equation 1 is used. In contrast to evaluating the calibration formula, if two or more pseudo fruit bodies with different sugar contents known in the present invention are measured, the calibration can be performed quickly and accurately (FIG. 2). One of the advantages of the artificial fruit calibration according to the present invention is that appropriate samples can be easily prepared for different measurement objects. That is, the calibration coefficients (Af1, Bf1) in Expression 1 cannot be applied to all objects, and, for example, different coefficients are naturally required for the high water content system (tomato) and the non-moisture system (peach). In the test, Af1 (slope value) is more important among the calibration coefficients of Equation 1, and if Af1 of the pseudo fruit and the actual fruit match, the calibration becomes easy. In the example of FIG. 1 (B), a pseudo fruit pair having the same AF1 (inclination value) as that of the fruit or vegetable to be measured can be created by changing the amount of the dispersoid added to the aqueous solution (see FIG. 3)), on the other hand, in the case of FIG. 1 (C), a pseudo fruit having a predetermined inclination value can be created by changing the gap between the double tubes and the material of the reflecting material (see FIG. 4).

Calibration coefficient Af of target fruits and vegetables
4 sets of glass double tube type pseudo fruit (type of FIG. 1 (C)) designed to be the same as 1 were made, and sucrose concentration was 10.6%, 13.5%, 16.8%, 1
A test experiment was conducted by enclosing a 9.8% aqueous solution. Experimental results are shown in FIG. It can be seen that linear and extremely reproducible measurement results were obtained. If you prepare this sample, if there is no discrepancy in the measured values at the next test,
It can be seen that there is no need to modify the calibration formula without preparing a sample of fruit.

Next, a measuring device using the simulated fruit according to the present invention will be described. FIG. 6 is an explanatory diagram of a case where the above-mentioned four types of simulated fruits are placed on a conveyor and automatic calibration is performed. The calibration mode can be automatically performed only by providing the measuring device with the verification mode and placing the four simulated fruits on the conveyor in a predetermined order.

Furthermore, if these artificial fruit bodies are built in the measuring device, it is not necessary to set the artificial fruit on the conveyor, and a fully automatic calibration operation can be realized. FIG. 7 is a block diagram of a measuring device having such a pseudo fruit body inside. The measuring light emitted from the light source 1 enters the fiber switching device 2 via the school attending fiber 8. The fiber switch 2 switches the incident light to the optical path 10 when measuring fruits and vegetables and to the optical path 11 side in the calibration mode. Optical path 1 when measuring fruits and vegetables
The measurement light projected from 0 is reflected by fruits and vegetables and enters the light receiving fiber 12, and enters the switch 2 through the plurality of plate-shaped pseudo fruit bodies 7 whose rotation is controlled by the stepping motor 6 in the calibration mode. Spectroscope 3
Performs spectral analysis of the luminous flux input as described above and sends it to the signal amplifier 4 to convert it into an electric signal. The processing device 5 analyzes the spectroscopic analysis information obtained as described above, and analyzes the measurement information and the calibration information of fruits and vegetables.

[0014]

As described above, since the pseudo object according to the present invention is set to have the characteristics similar to the reflected light characteristics of the actual object, a complicated calibration operation using the actual object is performed. The calibration of the measuring device can be performed quickly and with good reproducibility without the need for

[Brief description of the drawings]

FIG. 1 is a schematic diagram comparing the proofreading of an actual fruit and a pseudo fruit according to the present invention.

FIG. 2 is a diagram showing a comparison of proofreading results of actual fruits and pseudo fruits.

FIG. 3 is a diagram showing changes in measured sugar content with changes in the amount of cellulose in simulated fruits.

FIG. 4 is a diagram showing a difference in measured values when the distance between the double tubes is changed.

FIG. 5 is a diagram showing the results of a calibration experiment using simulated fruits.

FIG. 6 is a diagram showing a calibration method of a measuring device using four kinds of simulated fruits.

FIG. 7 is an explanatory diagram of a measuring device in which a simulated object is built in the device.

Claims (6)

[Claims] 1. A double tube structure comprising a cylindrical or spherical outer cylinder made of a transparent or semi-transparent material and an inner cylinder having a predetermined light reflectance, and a test is made in the gap of the double tube structure. A simulated object for calibrating a device for measuring internal properties of a subject, characterized by being filled with an aqueous solution containing a target substance contained in the body in a predetermined concentration. 2. A substance which is formed into a cylindrical or spherical transparent or translucent material and into which a predetermined dispersoid is added to an aqueous solution containing a target substance contained in a subject at a predetermined concentration to form a colloidal substance. A pseudo object for calibrating the internal property measuring instrument of a subject, characterized by being filled with. 3. A plurality of simulated objects according to claim 1 or 2 which are set to different predetermined target substance concentrations, sequentially irradiate the simulated light with the measurement light, and continuously measure reflected light by a measuring instrument. A calibration method characterized by calibrating the measuring device by measuring and comparing the measurement result with a predetermined evaluation formula. 4. The calibration method, wherein the measuring device is provided with the plurality of simulated objects in advance in the apparatus. 5. The simulated object according to claim 1, wherein the simulated object can be set to have a reflected light characteristic suitable for the object to be measured by appropriately changing the light reflectance and the distance between the double tubes. 6. The pseudo target object according to claim 2, wherein the pseudo light target property can be set to a reflected light characteristic suitable for the target object by appropriately changing the dispersoid concentration.