JP2922169B2 - Fruit softness measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for measuring the degree of softening of a fruit.

[0002]

2. Description of the Related Art It is required to objectively measure fruit ripeness as an index for determining the time of picking a fruit and determining the time of eating. Conventionally, the measurement of ripeness of a fruit mainly involves nondestructive sugar content. Measurement is used. In addition, since the fruit softens as it ripens, the degree of softening is also important as an index indicating ripeness.

As a method of measuring the softening degree of a fruit, a method of measuring the resonance frequency by applying vibration from the outside or a hit sensor for measuring the strain of the fruit to be measured by applying an external force to the fruit to be measured. Methods to be used and the like have been proposed.

[0004]

However, these conventional methods for measuring the degree of softening of a fruit involve applying mechanical force such as vibration or external force to the fruit from the outside. Because of the measurement of the fruit, the fruit is damaged and a destructive test is performed. In the case of a soft fruit, the measurement itself is impossible.

[0005] In view of the above circumstances, an object of the present invention is to provide a method for measuring the softening degree of a fruit, which can measure the softening degree of the fruit without applying a mechanical external force to the fruit.

[0006]

In order to achieve the above object, a first method for measuring the degree of softening of a fruit according to the present invention is to irradiate a fruit to be measured with a light beam and apply a light beam to the fruit to be measured. A point is a light receiving point apart from the light beam, and receives the internal scattered light that has reached a plurality of light receiving points having different distances from the light beam incident point, based on the received light amounts at the plurality of light receiving points, and obtaining the soft degree of fruits for the measuring.

In the first method for measuring the degree of softening of a fruit according to the present invention, the ratio of the amounts of received light at the plurality of light receiving points is determined, and the degree of softening of the fruit to be measured is determined based on the ratio. Is preferred. In this case, the correspondence between the ratio of the fruit to be measured and the same kind of fruit and the degree of softening of the same kind of fruit is determined, and after the ratio of the fruit to be measured is determined, based on the correspondence. hand,
It is preferable to convert the ratio into the softening degree of the fruit to be measured.

The second method for measuring the degree of softening of a fruit according to the present invention comprises irradiating a fruit to be measured with a light beam, and irradiating the fruit to be measured with a predetermined light receiving point distant from the light beam incident point. receiving light that has reached, based on the received light amount in the illumination light amount and the light-receiving point to the measuring for fruits, and obtains soft degree of fruits for該被measurement.

According to the present invention, the fruit to be measured is irradiated with a light beam, and the light which propagates inside the flesh of the fruit to be measured and reaches the light receiving point is received, thereby softening the fruit to be measured. The degree of softening can be measured without applying a mechanical external force to the fruit to be measured.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a schematic diagram illustrating a state in which a fruit is irradiated with a light beam and the degree of softening is measured. When a light beam 20 is irradiated on a certain irradiation point 11 of the fruit 10, the light beam 20 enters the inside of the fruit 10 and is scattered in the pulp as shown in FIG. The light sensors 32 and 3 which reach the two light receiving points 12 and 13 at the distances r ₁ and r ₂ respectively from the point 11 and are arranged at the light receiving points 12 and 13 respectively.
3 respectively.

Here, when the fruit 10 is matured, a phenomenon that changes the light absorption such as an increase in sugar content occurs simultaneously with softening of the pulp, but here, the overtone wavelength of the CH, CH ₂ bond (primary, secondary). By using light of a wavelength that avoids the following, the influence of absorption can be avoided, and thereby the degree of softening can be accurately measured. However, measure the ripeness of the fruit
If desired, do not measure pure softening,
The measurement including the sound may be performed.

FIG. 2 is a schematic diagram showing the amount of light at a point separated by a distance r from the irradiation point when one point (irradiation point) of the light scatterer is irradiated with a light beam. When light is applied to a point in the light scattering body having an infinite spread, the light spreads spherically around the irradiation point, and the fluence rate at a point at a distance r from the irradiation point (full solid angle integrated value of diffused light intensity)
[Phi (r) is, Φ (r) = (1 / 8πD) · {exp (-μ eff · r) / r} = 3μ s '/ 4π · exp {-√ (3μ a · μ s') · r ｝ / R (1) where μ _a is the absorption coefficient of the pulp, μ _s ′ is the scattering coefficient of the pulp, μ _eff is the effective absorption coefficient of the pulp, and μ _{eff
= √ (μ a · μ s} ') values D defined by is a diffusion _{constant, D = 1 / (3μ s} ' is a value defined in). It is known that This fluence rate Φ
(R) decreases as an exponential function according to the distance r, as shown in FIG.

The fluence rate Φ (r) is applied to the measurement of fruit softening degree as shown in FIG. Two light receiving points 1
The light receiving devices of the optical sensors 32, 32 disposed in the light emitting devices 2, 13, respectively, are as follows: Φ (r ₁ ) = C · 3 _μs ′ / 4π · exp (−μ _eff · r ₁ ) / r ₁ . 2) Φ (r ₂ ) = C · 3 _μs ′ / 4π · exp (−μ _eff · r ₂ ) / r ₂ (3) where C is a proportional constant common to the equations (2) and (3). It is. When the ratio k between Φ (r ₁ ) and Φ (r ₂ ) is obtained, k (λ) = Φ (r ₁ , λ) / Φ, considering that μ _eff is a function of the wavelength λ of light. (R ₂ , λ) (4) lnk (λ) = μ _eff (λ) · (r ₂ −r ₁ ) + ln (r ₂ / r ₁ ) (5) Two light receiving points 12 from the irradiation point 11, Each distance r to 13
₁ and r ₂ can be obtained in advance, so that the ratio lnk (λ) expressed by the equation (5) is determined by the effective absorption coefficient μ _eff of the pulp. Here, as described above, a _{μ eff (λ) = √ (} 3μ a · μ s') ... (6), since here were selected wavelength lambda that does not affect the absorption coefficient mu _a, the ratio By calculating lnk (λ), the scattering absorption coefficient μ _s ′ of the pulp can be obtained.

FIG. 3 is a graph showing the relationship between the scattering absorption coefficient μ _s ′ of the pulp and the degree of softening of the pulp. For fruits, it is not an infinite medium and the above formula does not strictly apply,
The softening degree and the scattering coefficient μ _s ′ show a strong correlation. Therefore, the softening degree of the fruit is measured using a conventional method, for example, a method using a hit sensor, and the scattering and absorption coefficient μ of the fruit is determined by the above-described method. By measuring _s ′ and obtaining a graph as shown in FIG. 3 in advance, in actual measurement, the scattering absorption coefficient μ _s ′ of the fruit is measured, and the measured scattering absorption coefficient μ _s ' can be converted to a degree of softening.

In the above embodiment, the two light sensors 32 and 33 are arranged to determine the ratio between the amounts of received light.
There may be only one optical sensor, and the softening degree of the fruit may be measured based on the ratio between the incident light amount of the light beam incident on the fruit 10 and the received light amount obtained by the optical sensor. in this case,
Only one of the equations (2) and (3) (for example, the equation (2)) is obtained, and there are two unknowns of the equation (2), C and μ _s ′. There is no need to separate μ _s ′, and by associating the ratio between the incident light amount and the received light amount (the received light amount standardized by the incident light amount) with the softening degree measured by the conventional method, The degree of softening of the fruit can be known from the converted light receiving amount.

[0016]

As described above, according to the present invention,
The degree of softening of the fruit can be measured without applying mechanical force to the fruit.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a state in which a light beam is applied to a fruit to measure a degree of softening.

FIG. 2 is a schematic diagram showing the amount of light at a point separated by a distance r from an irradiation point when one point (irradiation point) of the light scatterer is irradiated with a light beam.

FIG. 3 is a graph showing the relationship between the scattering absorption coefficient μ _s ' of the pulp and the softening degree of the pulp.

[Explanation of symbols]

 Reference Signs List 10 Fruit 11 Irradiation point 12, 13 Receiving point 20 Light beam 32, 33 Optical sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01N 21/00-21/01 G01N 21/17-21/61 G01B 11/00-11/30 JICST file ( JOIS)

Claims (4)

(57) [Claims] 1. A fruit to be measured is irradiated with a light beam, and the fruit to be measured is a light receiving point separated from a light beam incident point and has a different distance from the light beam incident point. a plurality of internal scattered light reaches the light receiving point respectively received, based on the received light amount in the plurality of light receiving points, the softening degree measuring method of fruit and obtains the soft degree of fruits under test . 2. The method for measuring the softening degree of a fruit according to claim 1, wherein a ratio between light receiving amounts at the plurality of light receiving points is obtained, and a softening degree of the fruit to be measured is obtained based on the ratio. . 3. The correspondence between the ratio of the fruit of the same kind as the fruit to be measured and the degree of softening of the fruit of the same kind is determined in advance, and the ratio of the fruit to be measured is determined. 3. The method according to claim 2, wherein the ratio is converted into the degree of softening of the fruit to be measured based on the ratio. 4. A light beam is applied to the fruit to be measured, and light that reaches a predetermined light receiving point of the fruit to be measured, which is separated from the light beam incident point, is received. based on the received light amount in the light receiving point and the irradiation light amount, the softening degree measuring method of the fruit, characterized by obtaining the soft degree of fruits for該被measurement.