JP3352848B2 - Pseudo-object for calibration of internal property measuring device and calibration method of internal property measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-destructive measurement of a pseudo fruit (simulated object) used for calibration of an apparatus for non-destructively measuring the internal properties of a subject such as fruits and vegetables and a non-destructive object. The present invention relates to a method for calibrating an apparatus.

[0002]

2. Description of the Related Art In order to quantitatively and nondestructively grasp the internal properties of fruits and vegetables, near-infrared light is projected onto a subject, and the reflected light and transmitted light are spectrally analyzed. Has been measured. In order to accurately analyze such internal components, it is important to properly set an accurate calibration curve (calibration formula) used for calculating an analysis value. Various methods have been proposed for obtaining the equation. For example, Iwamoto et al., "Introduction to Near Infrared Spectroscopy" (Koshobo), pp. 54-93, describes various data processing methods and analysis methods for improving the accuracy of the calibration equation.

[0003] Even if a correct calibration equation can be obtained by the above-described method, this equation must be periodically reviewed mainly for hardware reasons such as a change with time in the apparatus. Such hardware problems mainly include the following: Deviation of the wavelength of the spectroscopic unit in the measuring device Temporal change of the color temperature of the light source unit Temporal change due to deterioration of the light receiving element Electric amplification unit Change over time

[0004] Regarding the above, a model in which a wavelength standard body is installed in a measuring apparatus has also been developed (for example, Proceedings of the 10th Non-destructive Measurement Symposium “Conditions for Successful Near-Infrared Analysis”). As a countermeasure for-, calibration using a reflection or transmission standard (reference) is generally performed. For example, Japanese Patent Application Laid-Open Nos. 5-142036 and 6-25 describe a device having a built-in reference.
8225, JP-A-4-115142, JP-A-4-116
503 and JP-A-1-284758.

[0005] These prior arts all attempt to optically and electrically calibrate the measuring device using an inorganic reference to remove the influence of the device over time. However, as described above, even if the device is calibrated and the correct calibration equation is used,
The original signal (eg, absorption spectrum) handled in performing the internal analysis of the subject is extremely weak, and it is difficult to expect a long-term accurate measurement. Therefore, in order to guarantee the quality of the product for which the component has been measured, it is inevitable to periodically perform the test using the actual sample. However, calibration using real samples (especially fruits and vegetables) has the following problems. It is difficult to secure a sample (the acquisition time is limited, and a plurality of samples with different component values are required at the same time). The hassle of manually measuring the component values of a sample by hand. Possible errors in manual analysis of samples (analysis errors, errors resulting from non-uniformity of components in the sample). Calibration takes time because the calibration value is determined from the results of manual analysis of the sample.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and does not require the calibration of an apparatus for nondestructively measuring the internal components of fruits and vegetables by spectroscopic analysis without using an actual sample. The purpose of the present invention is to perform the method quickly and with good reproducibility by a simple method.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a calibration for generating a spectroscopic measurement value having a characteristic optically similar to that of a fruit and vegetable as a subject and corresponding to a predetermined component concentration of a target substance in advance. This is achieved by calibrating the device using two or more standard pseudo samples.

[0008]

FIG. 1 is a schematic diagram comparing the structure of a real fruit with the internal structure of two kinds of pseudo fruits (simulation objects) according to the present invention.

(A) shows the actual structure of the fruit. The flesh below the epidermis has a structure in which an aqueous solution of water, sugar, organic matter or the like has penetrated a network structure of cellulose or the like. (B) is a first embodiment of a pseudo fruit (pseudo fruit body) according to the present invention, which aims at realizing optical characteristics similar to the internal structure of a real fruit. Fill the inside of a container made of glass, transparent material such as polyethylene with a colloidal aqueous solution by mixing milk, paint, cellulose, etc., and add sucrose at the same concentration as the actual fruit, equivalent to the actual fruit Is configured to generate the reflection spectrum of Thus, in this example, since the optical characteristics are similar to the actual fruit, high-precision calibration can be expected, but it is difficult to create an appropriate dispersoid, and deterioration and sedimentation due to aging change occur. There is an easy side. (C) is an embodiment in which a transparent material such as glass or polyethylene is formed in a double-tube structure. A reflector is provided on the inner tube, and a sucrose aqueous solution having the same concentration as that of the actual fruit is transmitted and reflected by the reflector. This is an embodiment of the type that receives the light emitted. Since the aqueous solution contains only the target substance, the composition of the reflection spectrum is different from that of the actual fruit, but the aqueous solution is less likely to change over time or deteriorate.

[0010] The calibration formula for the sugar content of the fruit in the present measuring device is as follows. C_BX = Af1 · F (λ1, λ2,... Λn) + Bf1 Formula 1 where C_BX: measured sugar content F (λ1, λ2,... Λn): Absorption data of the measurement sample at a plurality of wavelengths Formed sugar content calculation functions Af1, Bf1: constants (calibration coefficients) In a test using a real fruit, which is usually performed, a correlation diagram is used between the actual analysis value that is manually performed and the measurement value calculated by Expression 1. In contrast to evaluating the calibration formula, the present invention allows quick and accurate calibration by measuring two or more known pseudo fruits having different sugar contents (FIG. 2). One of the advantages of the simulated fruit calibration according to the present invention is that an appropriate sample can be easily prepared for different measurement objects. That is, the calibration coefficients (Af1, Bf1) in Equation 1 cannot be applied to all the measurement objects, and for example, different coefficients are necessary for a multi-moisture system (tomato) and a non-moisture system (peach). . In the test, Af1 (slope value) is more important among the calibration coefficients of Expression 1, and if the Af1 of the pseudo fruit matches the Af1 of the actual fruit, the calibration becomes easier. In the embodiment of FIG. 1B, by changing the amount of the dispersoid added to the aqueous solution, a pseudo fruit having the same AF1 (inclination value) as the fruit and vegetable to be measured can be produced (FIG. 3). On the other hand, in the case of FIG. 1C, 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).

The calibration coefficient Af of the object to be measured
Four sets of glass double tube type pseudo fruit (type of FIG. 1 (C)) designed to be the same as 1 were prepared, and the sucrose concentration was 10.6%, 13.5%, 16.8%, 1
An assay experiment was performed by enclosing a 9.8% aqueous solution. FIG. 5 shows the experimental results. It can be seen that linear and extremely reproducible measurement results were obtained. By preparing this sample, if there is no deviation in the measured value at the next test,
It can be seen that there is no need to modify the calibration formula without preparing a sample of the actual fruit.

Next, a measuring apparatus using the artificial fruit according to the present invention will be described. FIG. 6 is an explanatory diagram in a case where the above-described four kinds of pseudo fruits are placed on a conveyor and automatic calibration is performed. The calibration mode can be automatically performed only by setting the test mode in the measuring device and placing the four pseudo fruits on the conveyor in a predetermined order.

Further, if these artificial fruits are incorporated in the measuring device, it is not necessary to set the artificial fruits on a conveyor, and a fully automatic calibration operation can be realized. FIG. 7 is a configuration diagram of a measuring device having such a simulated fruit therein. The measuring light emitted from the light source 1 enters the fiber switching device 2 via the school fiber 8.
The fiber switch 2 transmits the incident light to the optical path 10 when measuring fruits and vegetables, and the optical path 11 when in the calibration mode.
Switch to the side. In the fruit and vegetable measurement mode, the measurement light projected from the optical path 10 is reflected by the fruit and fruit and enters the light receiving fiber 12. Light enters 2. The spectroscope 3 spectrally analyzes the light beam input as described above, sends the light beam to the signal amplifier 4, and converts it into an electric signal. The processing device 5 analyzes the spectral analysis information obtained as described above, and analyzes the measurement information and the calibration information of the fruits and vegetables.

[0014]

As described above, the simulated fruit (simulated object) according to the present invention is set to have characteristics close to the reflected light characteristics of the actual measurement object.
Calibration of a measuring device can be performed quickly and with good reproducibility without having to perform a complicated calibration operation using an actual measurement object.

[Brief description of the drawings]

FIG. 1 is a schematic diagram comparing calibration of a real fruit and a pseudo fruit according to the present invention.

FIG. 2 is a diagram showing a comparison of calibration results between a real fruit and a pseudo fruit.

FIG. 3 is a diagram showing a change in measured sugar content according to a change in the amount of cellulose in a simulated fruit.

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

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

FIG. 6 is a diagram showing a method of calibrating a measuring device using four types of artificial fruits.

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-5105 (JP, A) JP-A-54-23586 (JP, A) JP-A-56-63242 (JP, A) JP-A 54-235 133179 (JP, A) Proc. Natl. Acad. Sc i. USA. 85, 4971-4975 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 21/00-21/61 JICST file (JOIS) Practical file (PATOLIS) Patent file (PATOLIS)

Claims (6)

(57) [Claims] 1. A double tube structure comprising a cylindrical or spherical outer tube made of a transparent or translucent material and an inner tube made of a light-reflecting material, wherein sucrose is prescribed in a gap between the double tube structures. A pseudo object for calibrating an internal property measuring device for a subject, which is filled with an aqueous solution containing a concentration. 2. A transparent or translucent material is formed into a cylinder or a sphere, and the inside thereof is filled with a colloidal substance by adding a predetermined dispersoid to an aqueous solution containing a predetermined concentration of sucrose. Object to be calibrated inside the subject. 3. A plurality of simulated objects according to claim 1 or 2, wherein the simulated objects are set to different predetermined sucrose concentrations, and the simulated objects are sequentially irradiated with measurement light, and the reflected light is continuously measured by a measuring device. And calibrating the measuring device by comparing the measurement result with a predetermined evaluation formula. 4. The calibration method according to claim 3, wherein the measurement device includes the plurality of pseudo objects in the device in advance. 5. The simulation according to claim 1, wherein by appropriately changing the light reflectance of the reflector and the interval between the double tubes, it is possible to set a reflected light characteristic according to an object to be measured. Object. 6. The pseudo object according to claim 2, wherein the reflected light characteristic can be set according to the measurement object by appropriately changing the dispersoid concentration.