JPH11337481A - Apparatus and method for measurement of internal quality of fruits and vegetables - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus and a method in which the time required for a data processing operation is shortened and in which the internal quality of fruits and vegetables can be measured at high speed and with high accuracy, by a method wherein light which is passed through the fruits and vegetables is divided into the prescribed number of frequency regions and light-receiving signal processing circuits corresponding to the respective regions are installed. SOLUTION: In a measuring apparatus for the internal quality of fruits and vegetables, light which is passed through an object 5 to be inspected is divided into the prescribed number of frequency regions by, e.g. a diffraction grating 3, and it is measured by photodiodes 20 which are arranged so as to correspond to the respective frequency regions. Obtained signals are processed by light-receiving signal processing circuits which correspond to the respective photodiodes 20, they are inputted to a CPU 27 as pieces of intensity data on the light transmitted through the respective frequency regions, and they are converted into data on the internal quality by a prescribed computing operation. When a sensor array composed of, e.g. MOS image sensors as charge storage-type light receiving elements is constituted, the transmitted light can be analyzed fine in many divided channels. In addition, the signal processing circuits can be constituted so as to be unified by using a multiplexer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to oranges, melons,
The present invention relates to a device for non-destructively measuring the quality such as internal sugar content of fruits and vegetables such as watermelon, and more particularly to a processing circuit for processing initial data obtained by measurement at higher speed and with higher accuracy.

[0002]

2. Description of the Related Art Generally, the evaluation of the internal quality of fruits and vegetables before shipment has been mainly carried out visually by a skilled inspector. In addition, in the case of certain fruits and vegetables, harvesting or shipping in a ripe state results in a decrease in taste at the time of sale, flouring of the pulp, etc. By leaving it at a temperature, it ripens to make it edible. Conventionally, the completion of such ripening was judged visually by the inspector as described above. However, there is no clear standard for the internal quality evaluation of such fruits and vegetables, and it is impossible to make an accurate judgment. It was difficult.

On the other hand, when near-infrared light is projected on fruits and vegetables,
Since components such as carbohydrates in fruits and vegetables absorb light of a specific wavelength, it is possible to know the internal quality such as sugar content of fruits and vegetables by analyzing the transmitted light transmitted through the fruits and vegetables. There is known a method of non-destructively determining the internal quality of fruits and vegetables using transmitted light.

[0004] Specifically, FIG. 4 shows an example of a schematic diagram of a device for measuring the internal quality of fruits and vegetables. In FIG. 4, the internal quality of a plurality of subjects 5 is continuously measured while the subject 5 which is a fruit or vegetable is conveyed on a conveying means 10 such as a conveyor. First, the presence of the subject 5 is confirmed by the position sensor 11 on the transport means. Next, light (hereinafter, simply referred to as light) having a predetermined frequency range is irradiated from the light source 1 to the subject 5 at a predetermined position A on the transport means. The irradiated light is transmitted to the outside of the subject 5 after light of a predetermined wavelength is absorbed by a saccharide or the like existing in the subject 5. The transmitted light is measured by the light receiving element 2, and the transmitted light obtained by the measurement is analyzed by the signal processing device 12, so that the internal quality of the subject 5 can be known.

However, the frequency range of light used for spectroscopic analysis of fruits and vegetables is wide, and in order to actually perform signal processing and obtain accurate internal quality, the frequency range is divided into a plurality of portions and each divided frequency region is It is necessary to perform signal processing. The following methods (1) and (2) are considered as a method of dividing the frequency domain and processing the signals.

(1) An interference filter that transmits only light in a predetermined frequency region is provided in a number corresponding to the number of divisions of the frequency region corresponding to the division number of the measurement frequency region, and the filters are continuously provided in the light receiving portion of the light receiving element. , The transmitted light in the divided frequency region is continuously sent to the signal processing device to perform signal processing. One measurement in the measurement frequency range is completed when all the filters pass through the light receiving portion. (2) For example, as described in Japanese Patent Application Laid-Open No. 7-22984, an array having a diffraction grating that divides a measurement wavelength in a light receiving portion and transmits the divided transmitted light in accordance with the number of divisions with an accumulation type sensor And a signal processing circuit sequentially performs signal processing on the data accumulated after the completion of one measurement by a single signal processing circuit (including an amplifier and the like).

[0007]

The time allowed for quality evaluation in the process of sorting fruits and vegetables is very short, and the evaluation of the fruits and vegetables in the transport state on the transport means is performed by a plurality of fruits and vegetables. Need to be performed continuously. But,
Since the internal quality of a fruit or vegetable varies greatly depending on its measurement site, it is necessary to evaluate a continuous and wide area as much as possible. In addition, in order to perform accurate evaluation, it is necessary to accumulate a sufficient amount of transmitted light.

However, in the case of the above method (1), since the fruits and vegetables move during the change of the interference filter, the measurement region shifts as the frequency region is changed. Is obtained discontinuously and only partially for the measurement area on fruits and vegetables. Further, for the same reason, the data obtained for each of the divided frequency regions is data for a different measurement region, so that it is difficult to obtain accurate internal quality measurement results. In addition, the measurement time for each divided frequency area becomes shorter as the number of divisions of the frequency area increases, and it is difficult to obtain a sufficient amount of transmitted light.

In the case of the above method (2), the transmitted light is divided by the diffraction grating at the same time. However, since the data stored in the array must be sent to the signal processing circuit serially, The data accumulation start time and the accumulation end time for each divided frequency region are sequentially shifted according to the data transfer time. Since such a time lag of the data accumulation timing for each divided wavelength is as small as tens of msec, the measurement area on the fruit or vegetable becomes discontinuous, or the measurement position of the data obtained for each division frequency area is different. The problem of the difference and the problem of the decrease in the amount of light accumulated per unit time are not as noticeable as in the case of the method (1). However, it is still insufficient to obtain a more accurate result of measuring the internal quality of fruits and vegetables or to reduce the time allowed for the quality measurement. Furthermore, it is necessary to perform a step of erasing and initializing data accumulated in each sensor on the array after one measurement is completed, which also poses a problem in reducing the time required for measurement.

In the above (2), as a method of solving the above-mentioned problem, a method of increasing the accumulation time of each frequency region to several tens msec is considered. However, in the case where external light other than transmitted light is received by the light receiving element or abnormal intensity data is generated due to dust or the like adhering to fruits and vegetables during a certain period of the accumulation time, the method is applied during the accumulation time. It is difficult to know the profile of the intensity data, and there is a risk that data containing an abnormal value may be used as it is.

Further, the actual intensity of the transmitted light greatly differs in each frequency region, and an appropriate amplification factor is selected when the stored data is signal-processed, and a baseline is set in accordance with the amplification factor. Above, signal processing for calculating the internal quality must be performed. As the accumulation time is shortened, the number of times that this signal processing is performed and the number of times that each sensor is initialized also increase. There was a risk that the measurement time would increase.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an apparatus for measuring the internal quality of fruits and vegetables by analyzing light transmitted through the fruits and vegetables and capable of performing high-speed and high-accuracy measurement. Aim.

[0013]

In order to solve the above-mentioned problems, an apparatus for measuring the internal quality of fruits and vegetables according to the present invention comprises a conveying means for conveying fruits and vegetables in a predetermined direction, and a sensor for confirming the presence of the fruits and vegetables being conveyed. A light projecting means for projecting light having a predetermined frequency range to the fruits and vegetables, a light receiving means for receiving the light transmitted through the fruits and vegetables, and calculating intensity data according to the transmitted light received by the light receiving means. A light-receiving signal processing circuit and an internal-quality-determination device for fruits and vegetables having an internal quality calculation circuit for calculating the internal quality of fruits and vegetables using intensity data, wherein the light-receiving means further converts a light having a predetermined frequency range into a predetermined number of lights. It has frequency domain dividing means for dividing into frequency domains, and it is assumed that the number of light receiving signal processing circuits is equal to the predetermined number.

[0014]

As described above, the apparatus for measuring the internal quality of fruits and vegetables divides the transmitted light received by the light receiving means by, for example, a diffraction grating into a predetermined number of frequency regions, and further separates the transmitted light into the predetermined number of frequency regions. A plurality of corresponding light receiving signal processing circuits calculate the intensity data corresponding to each divided region at the same time. As a result, even in the measurement in the transport state, the measurement is performed for all the frequency regions at each of the continuous measurement positions, and the measurement positions are discontinuous due to the occurrence of the temporal measurement position shift. This makes it possible to accurately analyze the internal quality of fruits and vegetables without resetting the light receiving unit for each measurement.

Further, the amount of light used as data per unit time is made larger than that in the case of using the accumulation type sensor described in the prior art in order to simultaneously process the transmitted light of all the divided areas. It is possible to perform more accurate internal quality evaluation of fruits and vegetables. Further, in the configuration of the present invention, it is easy to increase the number of divisions in the frequency domain when more accurate measurement is required, and to reduce the number of divisions when accuracy may be low. However, it is also possible to adopt a configuration in which the number of divisions is changed while the apparatus is operated according to the size of the non-sample or the measurement conditions.

As described above, the method using the accumulation type sensor may cause a delay in the measurement time. However, if the internal quality measurement device is used for research and development, for example, where a relatively long measurement time is allowed, the above-mentioned accumulation type sensor array can generally divide the frequency domain very finely. The measurement method using this is useful. In particular, the method of setting the accumulation time for each frequency region as short as a few milliseconds and dividing and measuring the internal quality of fruits and vegetables in a fine range more accurately knows the quality of fruits and vegetables, and the profile of the intensity data described above. It is also possible to know it, and it is considered to be particularly useful in research and development.

According to the present invention, even when the storage type sensor is used, since the light receiving signal processing circuit is provided in parallel, the accumulated data is sequentially sent to the light receiving signal processing circuit without waiting for the signal processing for each frequency domain. Since it is possible to perform signal processing and initialization in quasi-parallel by sending, it is possible to increase the number of divisions of the frequency domain using a storage type sensor array consisting of a large number of light receiving elements and to Even when the accumulation time of the measurement is set to be as short as several milliseconds, the increase in the measurement time is actually slightly suppressed. In addition, the same effect is obtained that the amount of displacement of the measurement position can be reduced and the amount of transmitted light received per unit time can be increased.

As the frequency domain dividing means for dividing into a predetermined number of frequency domains, a spectroscope and a photo sensor may be used in combination with the light receiving means, and a CCD sensor or the like may be used as the light receiving means. That is, the light receiving means and the frequency domain dividing means do not need to be particularly distinguished depending on the application, and a plurality of electrical signals are divided by a function of dividing transmitted light into a predetermined frequency domain and a function of converting light energy into electrical signals. Any configuration that generates this may be used.

[0019]

FIG. 1 is a block diagram showing a signal processing according to a first embodiment of the present invention. It differs from the prior art until the light (hereinafter, referred to as light) having a predetermined frequency range irradiated from the light source 1 to the non-sample 5 from the light source 1 is transmitted from the non-sample 5. Since there is no portion, the description is omitted here. In this embodiment, the light transmitted through the non-sample 5 is divided into n frequency regions λa to λx by the diffraction grating 3 immediately before the photodiode 20. Further, the photodiodes 20 are arranged corresponding to the number of divided frequency regions, and transmitted light in a predetermined frequency region is measured by the predetermined photodiode 20. still,
The signal processing routine in the light-receiving signal processing circuit including the current-voltage conversion amplifier, the gain amplifier, the low-pass filter, the voltage-frequency converter, and the counter according to each photodiode 20 is the same in all the light-receiving elements. Hereinafter, a signal processing routine in the case of λ1 will be described.

The divided transmitted light is supplied to the photodiode 2
The current is converted to a current by 0, and the current is further converted to a voltage signal by the current / voltage conversion amplifier 22a. After the obtained voltage signal is amplified by the gain amplifier 23a, the noise component is cut by the low-pass filter 24a, and the frequency is converted by the voltage-frequency converter 25a. Thereafter, the frequency is counted by the counter 26a for a predetermined integration time t. The counted frequency is input to the CPU 27 as intensity data Da = fa × t of the transmitted light λa applied to the photodiode 20.

Next, FIG. 2 shows a signal block diagram according to a second embodiment of the present invention. The difference from the first embodiment is that a sensor array 7 including a plurality of MOS type image sensors (accumulation type sensors) is used instead of the photodiode 20. In this embodiment, the light transmitted through the non-sample 5 is divided into n frequency regions λ1 to λn by the diffraction grating 3 immediately before the sensor array 7. Charges (accumulated data) corresponding to the respective divided frequency regions are sequentially sent from the sensor array 7 serially to the corresponding current-voltage conversion amplifiers. The following signal processing is the same as in the first embodiment.

In this embodiment, since the stored data sent serially from the sensor array 7 is processed in a quasi-parallel manner, the signal processing time is greatly increased even if an optimum gain is selected for each stored data. Does not occur. For this reason, there is an effect that it is possible to analyze transmitted light in detail using a MOS image sensor in which the number of divided channels is generally several hundred or more. Further, if it becomes possible for the sensor array 7 to transmit the accumulated electric charge to the current-voltage conversion circuit connected in parallel, the same effect as in the first embodiment can be obtained.

In the second embodiment, the number of light receiving signal processing circuits is equal to the number of divisions. Manufacturing costs increase significantly and are impractical.
Therefore, in the third embodiment, as shown in the signal block diagram of FIG. 3, the charge corresponding to each frequency region is converted into a voltage signal by a current / voltage conversion amplifier, and then a single gain amplifier is passed through a multiplexer 28. 23 The voltage signal is transmitted. As a result, the same effect as in the second embodiment can be obtained without significantly increasing the manufacturing cost.

Further, in the third embodiment, when it becomes possible to transmit the stored electric charges to the current-to-voltage conversion circuit connected in parallel with respect to the sensor array 7, a multiplexer 28 is arranged and multiplexed. The timing at which the conversion process is performed is not limited to after the current-voltage conversion, but may be after the signal amplification that requires the most processing time. In this case, almost the same effects as in the first embodiment can be obtained.

The intensity data input to the CPU 27 is converted into internal quality data by performing a predetermined operation.
These are displayed as images on a CRT or the like. It should be noted that the image display may be in a form in which only the suitability of the shipping time of the subject 5 is displayed on the basis of a predetermined utility, and further, only the suitability data is output without performing the image display, and the display is continuously performed to the measuring apparatus. The screening of the subject 5 may be performed in the transport device.

[0026]

According to the present invention, the data processing and analysis of the transmitted light transmitted through the fruits and vegetables can be greatly reduced with respect to the processing time in the prior art, and the internal quality measurement of the fruits and vegetables can be performed in a short time. And with high accuracy.

[Brief description of the drawings]

FIG. 1 is a signal processing block diagram according to a first embodiment of the present invention.

FIG. 2 is a signal processing block diagram according to a second embodiment of the present invention.

FIG. 3 is a signal processing block diagram according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a schematic configuration of a method for measuring the internal quality of fruits and vegetables using near-infrared light.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Light receiving element 3 Diffraction grating 5 Subject 7 Sensor array 10 Carrier 11 Position sensor 12 Signal processing device 20 Photodiode 22 Current-voltage conversion amplifier 23 Gain amplifier 24 Low-pass filter 25 Voltage-frequency converter 26 Counter 27 CPU 28 Multiplexer

Claims (7)

[Claims] 1. Conveying means for conveying fruits and vegetables in a predetermined direction, light emitting means for projecting light having a predetermined frequency range to the fruits and vegetables, and light receiving means for receiving light transmitted through the fruits and vegetables. And a light-receiving signal processing circuit for calculating intensity data corresponding to the transmitted light received by the light-receiving means, and an internal quality calculation circuit for calculating an internal quality of the fruits and vegetables using the intensity data. In the apparatus, the fruit and vegetable internal quality measuring device further includes a frequency domain dividing unit that divides light having a predetermined frequency region transmitted through the vegetable into a predetermined number of frequency regions and guides the light to the light receiving unit, An apparatus for measuring the internal quality of fruits and vegetables, wherein the light reception signal processing circuit is provided for each of a predetermined number of frequency regions. 2. The apparatus for measuring the internal quality of fruits and vegetables according to claim 1, wherein said light receiving means is a photoelectric conversion element which receives each of the lights divided into the predetermined number of frequency regions. 3. The inside of a vegetable or vegetable according to claim 1, wherein said light receiving means is a sensor array comprising a charge storage type light receiving element for receiving light divided into said predetermined number of frequency regions. Quality measuring device. 4. A light receiving signal processing circuit comprising: a first light receiving signal processing circuit portion including a current-voltage converter; a multiplexer connected to the first light receiving signal processing circuit portion;
A second light receiving signal processing circuit portion connected to the multiplexer for calculating intensity data, wherein the first light receiving signal processing circuit portion is provided corresponding to each of the light receiving elements. Equipment for measuring internal quality of fruits and vegetables. 5. A step of projecting light having a predetermined frequency range onto the fruits and vegetables in a state where the fruits and vegetables are transported, and calculating intensity data based on light transmitted from the fruits and vegetables, the step of transporting the fruits and vegetables. In a method for measuring the internal quality of fruits and vegetables, which is performed continuously in each region of the fruits and vegetables, and calculates the internal quality data of the fruits and vegetables using the intensity data, the transmitted light from the fruits and vegetables is a predetermined number of frequency regions. And by processing each of them in parallel, the intensity data corresponding to the light divided into the predetermined number of frequency regions are simultaneously calculated, and the integration is performed based on the intensity data, whereby the inside of the fruits and vegetables is obtained. A method for measuring the internal quality of fruits and vegetables, comprising calculating quality data. 6. A step of projecting light having a predetermined frequency range onto the fruits and vegetables in a state where the fruits and vegetables are transported, and calculating intensity data based on transmitted light from the fruits and vegetables, the step of transporting the fruits and vegetables. In the method for measuring the internal quality of fruits and vegetables, which is performed continuously in each region of the fruits and vegetables and calculates the internal quality data of the fruits and vegetables using the intensity data, the transmitted light from the fruits and vegetables is a predetermined number of frequency regions. , Each of which is received by light receiving means comprising a charge storage type light receiving element, and signals from the light receiving means corresponding to the predetermined number of divided frequency regions are processed in parallel to obtain the predetermined number. A method for calculating the internal quality data of the fruits and vegetables by calculating the intensity data corresponding to the light divided into the frequency regions, and calculating the internal quality data of the fruits and vegetables by performing the integration based on the intensity data. 7. A step of projecting light having a predetermined frequency region onto the fruits and vegetables in a state where the fruits and vegetables are transported, and calculating intensity data based on transmitted light from the fruits and vegetables, the step of transporting the fruits and vegetables. In a method for measuring the internal quality of fruits and vegetables, which is performed continuously in each region of the fruits and vegetables, and calculates the internal quality data of the fruits and vegetables using the intensity data, the transmitted light from the fruits and vegetables is a predetermined number of frequency regions. , And each of them is received by a light receiving means comprising a charge storage type light receiving element, and signals from the light receiving means corresponding to the predetermined number of divided frequency regions are processed in parallel and multiplexed. Calculating the intensity data according to the light divided into the predetermined number of frequency regions, and calculating the internal quality data of the fruits and vegetables by performing the integration based on the intensity data. Parts quality measurement method.