JP4215903B2 - Citrus float skin determination method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a floating skin determination method and apparatus for determining whether or not there is a gap at the boundary between a citrus peel and flesh and it is a floating skin.
[0002]
[Prior art]
Citrus fruits are boxed and shipped after class selection by size and grade selection by superiority and inferiority, but for grade selection, the appearance and poor color tone of the skin and skin are judged, and the skin and flesh An internal defect such as whether or not there is a void at the boundary portion of the boundary is judged, and after comprehensive evaluation, selection of excellent, excellent, good, etc. is performed.
For automatic determination of appearance defects such as poor shape and skin tone, the method of photographing a specimen with a color TV camera is used. For automatic determination of internal defects such as whether the skin is floating, the specimen is vibrated. There are known a method of measuring the moving speed while transporting (JP-A 64-58388), a method of detecting a transmission pattern by irradiating a specimen with electromagnetic waves (JP-A 10-170456), and the like.
[0003]
[Problems to be solved by the invention]
However, in the automatic determination of floating skin, the method of measuring the moving speed by conveying while vibrating, the friction coefficient changes depending on the surface state of the skin, and the moving speed also changes accordingly, so an accurate determination is not necessarily required I can't.
Further, in the method of detecting a transmission pattern by irradiating electromagnetic waves, a determination is made based on a change in the transmission amount at the boundary between the skin and the flesh, but since this is extremely delicate, an accurate determination cannot always be made.
[0004]
The present invention has been made in view of such conventional problems, and the object of the present invention is to provide a method and apparatus for determining the citrus peel that can automatically determine whether or not it is floated. It is to provide.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the method for determining the citrus peel of the present invention determines whether or not there is a float by injecting chopping air onto the peel of the citrus fruit and detecting the minute displacement of the peel generated thereby. It is characterized by.
[0006]
Here, if the output displacement signal obtained by detecting the minute displacement of the pericarp is discriminated into the movement displacement signal and the vibration displacement signal, the presence or absence of the floating skin can be determined even when the inspection object is moved. .
[0007]
Moreover, the citrus floating skin determining apparatus of the present invention can suitably carry out the above-mentioned citrus floating skin determining method, and includes an air compressor that discharges compressed air and a plurality of through holes at predetermined intervals in the circumferential direction. A rotating disk and a driving device that rotates the rotating disk at a predetermined rotational speed, a chopping air generator that generates chopping air, a displacement sensor that detects minute displacement of the skin, and a detection signal from this displacement sensor And an arithmetic unit that determines the presence or absence of a floating skin.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0009]
FIG. 1 is a configuration diagram of a floating skin determination device for determining the presence or absence of a floating skin while the inspection object is stationary. The floating skin determination device 1 includes an air compressor 2, a chopping air generator 3, a displacement sensor 4, It is comprised from the arithmetic unit 5.
[0010]
As the air compressor 2, it is preferable to use a centrifugal compressor having a discharge amount of 10 ⁻⁵ to 10 ⁻³ m ³ / min and a discharge pressure of 2 to 5 kg / cm ² .
[0011]
The chopping air generator 3 includes a rotating disk 6 and a driving device 7, and through holes 6a, 6a,... Are formed in the rotating disk 6 at predetermined intervals in the circumferential direction. The through holes 6a are preferably circular holes having a diameter of 1 to 5 mm, and are preferably formed at intervals of 30 to 45 °. The rotational speed of the rotating disk 6 is preferably set to 15 to 100 rpm. According to this, chopping air of 120 to 1200 pulses / min can be generated.
[0012]
As the displacement sensor 4, it is preferable to use a reflective displacement sensor made of a light emitting diode, a semiconductor laser or the like and having a response speed of 50 μs to 5 ms and a measurement accuracy of about ± 10 μm.
[0013]
The arithmetic unit 5 is composed of an A / D converter, a frequency filter, a microcomputer, etc., converts the analog detection signal from the displacement sensor 4 into a digital signal, passes a signal in a predetermined frequency band, and transmits a movement displacement signal and a vibration displacement signal. And the presence or absence of floating skin is determined.
[0014]
Next, the case where the above-mentioned floating skin determination apparatus 1 is used for the floating skin determination method of the present invention will be described.
[0015]
Compressed air discharged from the air compressor 2 at a discharge rate of 10 ⁻⁵ m ³ / min and a discharge pressure of 2 kg / cm ² is provided with circular through holes 6a, 6a,. The chopping air generating device 3 generates chopping air of 180 pulses / min by colliding with the rotating disk 6 that is drilled and rotated at 30 rpm.
[0016]
Then, the generated chopping air is sprayed onto the peel of the citrus fruit that is the inspection object, and the minute displacement of the peel is detected by the displacement sensor 4.
Here, when there is a floating skin in the fruit, the skin is vibrated minutely by the gap at the boundary between the skin and the flesh, so that the frequency of the chopping air from the displacement sensor 4 has the same frequency as shown by the solid line in FIG. A vibration displacement signal W _s is output.
[0017]
Therefore, in the state where the inspection object is stationary, the presence or absence of the floating skin can be determined based on whether or not the vibration displacement signal W _s is output.
Then, whether or not the vibration displacement signal W _s is output is determined by the arithmetic unit 5 based on whether or not the vibration displacement signal W _s is equal to or greater than a set threshold value.
[0018]
When actually selecting citrus fruits, since it is necessary to quickly determine a large number of inspection objects, as shown in FIG. 3, the inspection object A is moved by a conveying device 8 such as a conveying belt. Determine the presence or absence of skin.
3 includes an air compressor 2, two chopping air generators 3 and 3, two displacement sensors 4 and 4, and an arithmetic device 5. It is the same as that in the floating skin determination apparatus 1 shown in FIG.
[0019]
The case of using the above-described skin deciding device 11 will be described as a method for judging the buoyant skin of the present invention.
[0020]
Similarly to the above, after branching compressed air discharged from the air compressor 2 at a discharge rate of 10 ⁻³ m ³ / min and a discharge pressure of 5 kg / cm ² , a circular shape having a diameter of 5 mm at intervals of 30 ° in the circumferential direction. Through holes 6a, 6a,... Are made to collide with rotating disks 6 and 6 rotated at 50 rpm, and chopping air of 600 pulses / min is generated in the chopping air generators 3 and 3.
[0021]
The generated chopping air is sprayed from two directions onto the peel of the citrus fruit that is the object to be inspected, while minute displacement of the peel is detected from the two directions by the displacement sensors 4 and 4.
Here, since the fruit is moved by the conveying device 8, and when there is a floating skin in the fruit, the fruit skin slightly vibrates due to the gap at the boundary between the fruit skin and the pulp, so that a solid line in FIG. As shown, the displacement sensor 4 outputs an output displacement signal W _m0 in which the movement displacement signal W _m1 and the vibration displacement signal W _m2 are superimposed.
[0022]
Similarly to the above, the vibration displacement signal W _m2 has the same frequency as the frequency of the chopping air, and if the chopping air is regarded as a δ function, its vibration response is obtained.
Therefore, by passing through a frequency filter by Fourier transform, the output displacement signal W _m0 is converted into a movement displacement signal W _m1 indicated by a dotted line in FIG. 4B and a vibration displacement signal W _m2 indicated by a solid line in FIG. 4C. And discriminated.
[0023]
Therefore, even when the inspection object is moved, the presence or absence of the floating skin can be determined based on whether or not the vibration displacement signal W _m2 is output.
Then, whether or not the vibration displacement signal W _m2 is output is determined by the arithmetic unit 5 based on whether or not the vibration displacement signal W _m2 is _equal to or greater than a set threshold value.
[0024]
As described above, the floating skin determination method of the present invention is for determining the presence or absence of floating skin by detecting the minute vibrations of the skin caused by jetting chopping air onto the skin of citrus fruits, Since it propagates through the entire pericarp, it can be sufficiently detected even at a part slightly separated from the injection part, and a more accurate determination can be made.
[0025]
Moreover, according to the floating skin determination apparatus of this invention, the floating skin determination method of this invention can be implemented suitably.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a buoyant skin determination apparatus for determining the presence or absence of a buoyant skin while an inspection object is stationary.
FIG. 2 is a diagram illustrating a vibration displacement signal W _s output from a displacement sensor of the floating skin determination apparatus of FIG. 1;
FIG. 3 is a configuration diagram of a buoyant skin determining apparatus for determining the presence or absence of a buoyant skin while moving an inspection object.
4A is an output displacement signal W _m0 output from the displacement sensor of the floating skin determination apparatus of FIG. 3, FIG. 4B is a movement displacement signal W _m1 discriminated by a frequency filter, and FIG. 4C is a vibration. It is a figure which shows the displacement signal _Wm2 .
[Explanation of symbols]
1,11 Floating skin determination device 2 Air compressor 3 Chopping air generator 4 Displacement sensor 5 Arithmetic device 6 Rotating disk 6a Through hole 7 Drive device

Claims (3)

A method for determining a citrus peel, wherein chopping air is jetted onto the peel of a citrus fruit, and the presence or absence of a float is determined by detecting a minute displacement of the peel generated thereby. The method according to claim 1, wherein an output displacement signal obtained by detecting a minute displacement of a fruit skin is discriminated into a movement displacement signal and a vibration displacement signal. A chopping air generator that generates chopping air, comprising an air compressor that discharges compressed air, a rotating disk having a plurality of through holes formed in the circumferential direction at predetermined intervals, and a driving device that rotates the rotating disk at a predetermined rotation speed. A citrus floating skin judging device comprising: a displacement sensor for detecting minute displacements of the fruit skin; and an arithmetic device for processing a detection signal from the displacement sensor to determine the presence or absence of the floating skin.

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