CN100483109C - Portable fruit sugar content non-destructive detection device capable of weighing - Google Patents

Abstract

The invention discloses a portable non-destructive detection device for fruit sugar content with weighing. The cover of the chassis is equipped with a display and a keyboard, and the inside of the chassis is equipped with a printer, a microprocessor, a spectrometer, a weighing system composed of an amplifier, an A/D converter and a load cell, a display, a keyboard, a printer, a spectrometer and A/D The converters are respectively connected to the microprocessor; the chassis is equipped with a weighing pan and a fruit carrying plate connected to the load cell, and the fruit carrying plate has two oblique holes facing the center of the circle, and the detection head is placed in one of the fruit carrying plate’s oblique holes. The hole is connected with the spectrometer, and the case is equipped with a near-infrared light source that can irradiate the fruit from directly above or from the side, or the near-infrared light source is installed in the case, and the light source fiber installed in another oblique hole of the fruit carrying plate irradiates to the fruit. The invention has simple structure and small volume, is suitable for on-site detection, can simultaneously detect two indexes of fruit weight and internal quality sugar content, and realizes price evaluation and simultaneous measurement and sales of fruits according to quality.

Description

Portable non-destructive detection device for sugar content of fruit with weighing

technical field

The invention relates to a device for nondestructive detection of fruit quality, in particular to a portable nondestructive detection device for sugar content of fruit with weighing.

Background technique

With the continuous increase of fruit production and the continuous improvement of people's living standards, consumers pay more and more attention to the internal quality such as taste, sugar content, acidity, etc. when purchasing fruits, and the sugar content of fruits is an important factor for evaluating fruit maturity and fruit quality. an important indicator. At present, the inspection of the internal quality of fruits is often based on destructive chemical analysis, such as anthrone colorimetry or sugar meter for sugar content, potentiometric method (pH meter) for acidity, and colorimetry and high-phase chromatography for vitamin content. These methods all have problems such as cumbersome sample preparation, long analysis time, high detection cost and low detection accuracy. Therefore, the research on the portable rapid non-destructive detection device for the internal quality of fruits is an important step to realize the scientific management of fruits during production (if the scientific basis of the actual harvest period is whether the fruit meets the minimum sugar content requirements of high-quality fruits) and post-production sales according to quality. Work. Based on the present situation that the portable non-destructive testing device for the internal quality of fruit is immature, perfect and has few commercial applications, the present invention provides a cross-selection based on spectral analysis technology, optical fiber sensing technology, chemometrics technology and other technologies. The sugar content, the most important index in the internal quality of fruit, is used as the detection and evaluation index, and a portable non-destructive detection device for fruit sugar content with weighing function is developed.

At present, foreign countries have carried out some basic research on portable equipment for non-destructive testing of fruit internal quality. For example, Japan has developed a portable sugar meter based on visible and near-infrared rays. The sugar content detection range is 5-30Brix% (sugar content), and the detection speed is 3 seconds. In addition, countries such as Germany, Israel, and New Zealand have successively carried out near-infrared spectroscopy analysis and research on the sugar content, defects, and maturity of fruits, and developed corresponding portable testing equipment, but not many have been put into actual production and application, mainly because The signal of portable detection is too weak, the detection accuracy is not high and the adaptability is poor.

In Japanese Patent No.09-089767, a portable device for detecting apple sugar content using near-infrared is described. This method and device is to divide the reflected light of the fruit into different components after passing through the spectroscopic system (concave diffraction grating and spectroscopic mirror inside). The light of the wavelength is incident on the photoelectric conversion unit, and by calculating the absorbance, second differential processing, and using the spectral values at 912nm and 888nm to establish a prediction model, it is considered that it can be used for on-site detection of fruit quality on orchard trees. However, in this structure, the spectroscopic accuracy is easily affected by external factors (vibration, temperature), etc., so the detection accuracy is not high.

Patent No.02808798.4 filed in China by Maeda Hiroshi et al. describes a hand-held detection device for non-destructive inspection of the internal quality of the inspection object through spectral analysis. The difference from the above technology is that in this technology, the diffraction grating is replaced by a small beam splitter that is compactly combined with a linear continuously variable interference filter and a linear silicon array sensor, so the structure is more compact. However, in this hand-held sugar content detection device, as in the above-mentioned patent, the fruit sugar content is detected by detecting the reflected light of the fruit. This method can only detect thin-skinned fruits. For thick-skinned fruits, due to the limited depth of light entering the fruit, it cannot Correctly reflect the internal quality of the fruit.

In domestic patent No.200510056732.3, a portable fruit internal quality non-destructive testing device is described. In this technology, a circle of LED light source is used to irradiate the object (fruit) to be tested, and the photodetectors on the top and bottom are used to detect the near-infrared light transmitted from the fruit, and the fruit quality (water quality) is realized by establishing a prediction model. heart disease degree) detection and classification. In this portable non-destructive testing device for the internal quality of fruit, the sample window is closed, so the detection is easily affected by the ambient temperature. Although a temperature sensor is arranged near the photoelectric detector and the light source in the design, and temperature compensation is considered in the detection model, there is still the problem of low detection accuracy caused thereby, and the cost of the device is increased. In addition There is also the problem of impact on fruit quality due to heat dissipation difficulties.

In addition, fruit weight is the basis for fruit measurement, and no one has proposed a portable detection device that can simultaneously detect fruit weight and internal quality sugar content.

Contents of the invention

The invention provides a portable non-destructive detection device for sugar content of fruit with a weighing device, so as to meet the needs of commodity sales based on quality and simultaneous measurement.

The technical scheme that the present invention adopts is as follows:

A display and a keyboard are arranged on an outer cover of the main body case, and a printer, a microprocessor, a spectrometer, a weighing system composed of an amplifier, an A/D converter and a load cell are arranged in the main case, and the display, keyboard, printer, The spectrometer and the converter are respectively connected to the microprocessor; a weighing pan connected to the load cell is installed on the main chassis, and the fruit carrying plate of the tested fruit is installed on the weighing pan. The fruit carrying plate has two openings pointing to the center of the tested fruit. The angle between the two oblique holes is 45°～90°. The detection head is put into one oblique hole of the fruit carrying tray to connect with the spectrometer. A near-infrared light source irradiates the fruit to be tested, or the near-infrared light source is installed in the main chassis, and irradiates the fruit to be tested through a light source optical fiber installed in another oblique through hole of the fruit carrying tray.

The light source frame is equipped with a near-infrared light source that can irradiate the fruit to be tested from directly above or from the side, and a vertical rod that can slide up and down on the flange is installed on the flange on the other side of the main body chassis, and the end of the vertical rod A movable arm is installed, one end of the reinforcing rod is hinged with the movable arm, the other end of the reinforcing rod is hinged with the straight groove of the vertical rod, and a near-infrared light source is installed on the movable arm.

The detection head is put into an oblique through hole of the fruit carrying tray, and the detection head is at an angle of 25° to 45° to the center of the fruit to be tested.

The structure of the fruit carrying plate is a concave cylindrical plate, and the material is black rubber that is light-shielding. The upper plane of the fruit carrying plate will bend under the action of the tested fruit and be in close contact with the surface of the tested fruit to avoid the light emitted by the near-infrared light source. directly into the detection head.

The beneficial effect of the present invention is that it has a simple structure and can simultaneously detect the weight of the fruit and the internal quality and sugar content index, and when applied to the on-site sales of the fruit, it can realize the price evaluation according to the quality and the sales by measurement at the same time.

Description of drawings

Fig. 1 is an overall schematic diagram of an embodiment of the present invention;

Fig. 2 is an overall schematic diagram of another embodiment of the present invention;

Fig. 3 is a schematic diagram of main parts of another embodiment of the sugar content detection system of the present invention;

Fig. 4 is a sectional view of main parts of the present invention;

Fig. 5 is a control circuit diagram of the present invention;

Fig. 6 is a structural schematic diagram of two working positions of the light source frame of the present invention;

Fig. 7 is the result of the sugar content detection model of the present invention predicting the sugar content of navel oranges.

In the figure: 1. Fruit under test; 2. Light source frame; 3. Main chassis; 4. Display; 5. Keyboard; 6. Base; 7. Switch; 8. Printer; 9. Microcontroller; 10. Weighing system ; 11, amplifier; 12, A/D converter; 13, load cell; 20, vertical rod; 21, movable arm; 22, reinforcing rod; 23, fastener; 24, flange; 25, weighing pan; 101. Fruit carrying tray; 102. Near-infrared light source; 103. Detection optical fiber; 104. Spectrometer; 105. Concentrating cover; 106. Light source optical fiber; 107. Detection head.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Fig. 1, Fig. 2 and Fig. 5, the portable fruit sugar content non-destructive testing device with weighing is provided with a display 4 and a keyboard 5 on the main body casing 3-outside cover plate, and a printer 8 is arranged in the main body casing 3, and the microprocessor 9, spectrometer 104 (such as portable optical fiber spectrometer INCE-9310MT, including CCD detector, 2048Pixels), a weighing system composed of amplifier 11, A/D converter 12 and load cell 13 (such as SPM load cell) 10, display 4, keyboard 5, printer 8, spectrometer 104 and A/D converter 12 are respectively connected with microprocessor 9; There is a fruit carrying plate 101 of the fruit to be tested 1, and the fruit carrying plate 101 is provided with two oblique through holes pointing to the center of the tested fruit 1, and the two oblique through holes form a 45°-90° angle, and the detection head 107 is put into the fruit carrying plate 101 A slanted through hole is connected to the spectrometer 104, and the near-infrared light source 102 that can irradiate the tested fruit 1 from directly above or from the side is installed on the light source frame 2 on the other side of the main body chassis 3, or the near-infrared light source 102 is installed on the fruit. Another oblique through hole of the carrier plate 101. Alternatively, the near-infrared light source 102 is installed in the main body cabinet 3, and irradiates the tested fruit 1 through the light source optical fiber 106 installed in another oblique hole of the fruit carrying tray 101.

As shown in Fig. 1, Fig. 2 and Fig. 6, the near-infrared light source (such as tungsten halogen lamp) 102 that can irradiate the fruit 1 to be tested from directly above or from the side is installed on the light source frame 2, and on the other side of the main body chassis 3 The vertical bar 20 that can slide up and down on the flange 24 is housed on the flange 24 of the outside, the movable arm 21 is equipped with at the end of the vertical rod 20, and one end of the reinforcing rod 22 is hinged with the movable arm 21, and the other end of the reinforcing rod 22 is connected with the movable arm 21. The vertical bar 20 is hinged with a straight groove, and the movable arm 21 is equipped with a near-infrared light source 102 . When the near-infrared light source 102 irradiates the tested fruit 1 from directly above, as shown in FIG. 1 . When the near-infrared light source 102 irradiates the tested fruit 1 from the side, as shown in FIG. 2 .

As shown in FIGS. 3 and 4 , the detection head 107 is put into an oblique through hole of the fruit carrying tray 101 , and the detection head 107 forms an angle of 25° to 45° with the center of the tested fruit 1 .

As shown in Fig. 3 and Fig. 4, the structure of the fruit carrying plate 101 is a concave cylindrical plate, and the material is light-shielding black rubber. The close contact of the surface of the fruit 1 can prevent the light emitted by the near-infrared light source 102 from directly entering the detection head 107 and affecting the detection accuracy.

As shown in FIG. 1 and FIG. 4 , when the near-infrared light source 102 irradiates the tested fruit 1 from directly above, the spectrometer 104 collects transmitted light through the detection head 107 and the detection optical fiber 103 . This detection method is full transmission detection, which is suitable for the internal quality detection of thin-skinned or small-sized tested fruits 1.

As shown in Figure 2, Figure 4 and Figure 6, by adjusting the light source frame 2, after removing the reinforcing rod 22, the movable arm 21 is installed on the vertical rod 20 through the fastener 23, and adjusted according to the height of the fruit 1 to be tested. The location of the near-infrared light source 102 . The near-infrared light source 102 irradiates the tested fruit 1 from the side, and the spectrometer 104 collects transmitted light through the detection head 107 and the detection optical fiber 103 . This detection method is semi-transmissive detection, which is suitable for internal quality detection of apples, pears, watermelons, melons and other fruits.

As shown in Figure 3, the near-infrared light source 102 is installed in the main body cabinet 3, irradiates the fruit 1 to be tested through the light source optical fiber 106 installed in another oblique through hole of the fruit carrying plate 101, and the spectrometer 104 passes through the detection head 107 and the detection The optical fiber 103 collects the transmitted light. This detection method is semi-transmissive detection, which is suitable for internal quality detection of apples, pears, watermelons, melons and other fruits.

The following figure will introduce the working process:

When the fruit 1 was loaded into the fruit carrying tray 101, its weight caused the load cell 13 installed between the weighing pan 25 and the base 6 to deform, and output an electrical signal proportional to the weight. After the electrical signal was amplified by the amplifier 11, Input the A/D converter 12 to convert, and the converted frequency signal is directly sent to the 8031 microprocessor 9 to calculate the weight of the measured fruit 1; simultaneously open the switch 7, and the near-infrared light source 102 irradiates under the effect of the condenser 105 On the tested fruit 1, the spectrometer 104 detects the transmitted light from the tested fruit 1 to obtain a spectral data, and the spectral data is input in the 8031 microprocessor 9, and the microprocessor 9 extracts the spectral information under the effective wavelength through the program (such as Transmittance) and input into the sugar content detection model (Formula 1), calculate the internal quality sugar content value of the tested fruit 1. On the one hand, the microprocessor 9 inputs the measured value to the display 4 to display the value, and on the other hand, the measured value is input to the printer 8, and the measured value is printed on the label.

C＝a ₀ +a ₁ T(λ ₁ )+a ₂ T(λ ₂ )+a ₃ T(λ ₃ ) (1)

In the formula, C represents the sugar content of the fruit, λ is the wavelength, T(λ ₁ ) is the transmittance at the wavelength λ ₁ =838nm, T(λ ₂ ) is the transmittance at the wavelength λ ₂ =912nm, and T(λ ₃ ) is the wavelength The transmittance at λ ₃ =982nm, the coefficients a ₀ , a ₁ , a ₂ and a ₃ are obtained by using stepwise linear regression method after testing different fruit samples.

C＝8.0246-0.0578T(838)-2.54T(912)+2.1837T(982) (2)

Formula 2 is the navel orange sugar content prediction model obtained by using the stepwise linear regression method after the navel orange test. As shown in Figure 7, the result shown is the comparison between the predicted value of sugar content of 55 navel oranges and the artificial destructive detection value (measured value) by using equation (Formula 2).

Claims (3)

1. Portable non-destructive detection device for sugar content of fruit with weighing, characterized in that: a display (4) and a keyboard (5) are arranged on an outer cover plate of the main body case (3), and a printer (8) is arranged in the main body case (3) ), microprocessor (9), spectrometer (104), weighing system (10) consisting of amplifier (11), A/D converter (12) and load cell (13), display (4), keyboard (5), printer (8), spectrometer (104) and A/D converter (12) are connected with microprocessor (9) respectively; The weighing pan (25), the fruit carrying plate (101) of the tested fruit (1) is housed on the weighing pan (25), the fruit carrying plate (101) has two oblique through holes pointing to the center of the measured fruit (1), The two oblique through holes form 45°～90°, and the detection head (107) is put into an oblique through hole of the fruit carrying plate (101) to be connected with the spectrometer (104), and the light source frame ( 2) A near-infrared light source (102) capable of irradiating the tested fruit (1) from directly above or from the side is installed on the top, or the near-infrared light source (102) is installed in the main chassis (3), and is installed on the fruit carrying tray (101 ) light source optical fiber (106) in another oblique through hole to irradiate the measured fruit (1). 2. The portable non-destructive testing device for fruit sugar content with weighing according to claim 1, characterized in that: the light source frame (2) is equipped with a near-surface light that can irradiate the tested fruit (1) from directly above or from the side. Infrared light source (102), the vertical bar (20) that can slide up and down on the flange (24) is housed on the flange (24) on the other outside of main body cabinet (3), vertical bar (20) end is equipped with Movable arm (21), one end of reinforcing rod (22) is hinged with movable arm (21), and the other end of reinforcing rod (22) is hinged with vertical bar (20) straight groove, and near infrared light source (21) is housed on movable arm (21) 102). 3. The portable non-destructive detection device for fruit sugar content with weighing according to claim 1, characterized in that: the structure of the fruit carrying plate (101) is a concave cylindrical plate, and the material is black rubber that is light-shielding, and the fruit carrying plate The upper plane of the plate (101) will bend under the action of the tested fruit (1) and be in close contact with the surface of the tested fruit (1), preventing light from the near-infrared light source (102) from directly entering the detection head (107).

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