JP2007108124A - Freshness sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the point at issue wherein it is difficult to judge freshness of perishable foods on the handling spot of perishable foods in a real time or to perform the total inspection of the perishable foods because chemical analysis is performed in the conventional judge of freshness. <P>SOLUTION: This freshness sensor S1 is equipped with a spectroscope 2 for spectrally diffracting the reflected light from a measuring target A to form reflection spectrum, an image element 3 for receiving the reflection spectrum to convert it to an electric signal, a central control device 4 for converting the electric signal from the image element 3 to measuring data, and a memory device 5 for storing acquired reference data of the measuring target A, and is constituted so as to judge the freshness of the measuring target A on the basis of the measuring data and reference data in the central control device 4. This sensor can judge freshness in a non-destructive manner in a real time and correspond to the total inspection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly relates to a freshness sensor that is used to determine the freshness of a food whose freshness decreases with time, such as fresh food.

  Conventionally, as a method for determining the freshness of fresh food, there is a method of determining the freshness of fresh food by collecting a sample from fresh food, and chemically analyzing the sample to evaluate the chemical components of carbohydrates. It was.

  However, in the conventional freshness determination as described above, since chemical analysis is performed, the analytical equipment must be large, and it takes a long time to obtain the determination result, and handles fresh food. There is a problem that real-time freshness judgment cannot be performed on site, and since sampling is performed, a part of the fresh food is damaged as a result, and it is difficult to perform 100% inspection. It was.

  The present invention has been made in view of the above-described conventional situation, and in performing freshness determination of a measurement object such as fresh food, by utilizing the temporal change characteristic of the reflection spectrum, nondestructively and in real time. It is an object of the present invention to provide a freshness sensor that can perform freshness determination and can cope with downsizing of the apparatus and 100% inspection.

  A freshness sensor according to the present invention is a freshness sensor for a measurement object whose freshness decreases with time, a spectroscope that forms a reflection spectrum by dispersing reflected light from the measurement object, and a spectrometer Element that receives the reflection spectrum of the light and converts it into an electrical signal, a central controller that uses the electrical signal from the image element as measurement data of the reflection spectrum, and data of the reflection spectrum of the measurement object acquired in advance as reference data A storage device is provided, and the central controller determines the freshness of the measurement object based on the measurement data and the reference data from the storage device. The above configuration is a means for solving the conventional problems. .

  In addition, the freshness sensor according to the present invention is characterized in that it includes a light source that irradiates light to a measurement object as a more preferred embodiment, and the image element is an artificial retina LSI having a projection calculation function. And further comprising an external output terminal for outputting a freshness determination result obtained by the central control unit, and further comprising a multilayer electronic substrate comprising the spectroscope, the image element, the central control unit and the storage device. It is characterized in that it was provided.

  In the freshness determination method according to the present invention, when determining the freshness of a measurement object whose freshness decreases with time, the reflected light from the measurement object is dispersed to form a reflection spectrum. The data is measured data, and the reflection spectrum data of the measurement object acquired in advance is used as reference data, and the freshness of the measurement object is determined based on the measurement data and the reference data.

  The freshness sensor of the present invention can determine the freshness of the measurement object in a non-destructive manner in real time by using the time-dependent change characteristic of the reflection spectrum obtained from the measurement object such as fresh food. Compared with the conventional freshness determination that has been performed, it is possible to easily cope with downsizing of the apparatus and 100% inspection.

  In addition, since the freshness sensor of the present invention is provided with a light source, it has a compact structure, and can maintain a constant reflection spectrum formation condition by keeping the amount of light irradiated to the measurement object constant. The determination accuracy can be improved.

  Furthermore, the freshness sensor of the present invention employs an artificial retinal LSI having a projection calculation function in the image element, thereby reducing the load on the central controller and reducing the calculation processing time by performing image processing in an analog manner. Can do.

  Furthermore, since the freshness sensor of the present invention is provided with the external output terminal, the interface with the external device can be facilitated, and can be incorporated into various electronic devices, thereby expanding the application range.

  Furthermore, the freshness sensor of the present invention can make the entire apparatus more compact by providing each device on a multilayer electronic substrate, such as a portable electronic terminal device including a mobile phone, a refrigerator, a cooler box, etc. It can be incorporated into a storage device.

  Furthermore, according to the freshness determination method of the present invention, the freshness of the measurement object is determined non-destructively and in real time by using the time-dependent change characteristic of the reflection spectrum obtained from the measurement object such as fresh food. Compared with the conventional freshness determination in which chemical analysis is performed, the apparatus can be reduced in size and can also be used for 100% inspection of measurement objects.

  FIG. 1 is a diagram for explaining an embodiment of a freshness sensor according to the present invention.

  The illustrated freshness sensor S1 is a measurement object M whose freshness decreases with the passage of time. In brief, the light source 1 that irradiates the measurement object M with light, and the reflected light L from the measurement object M 2 which forms a reflection spectrum by splitting the spectrum, an image element 3 which receives the reflection spectrum from the spectrometer 2 and converts it into an electric signal, and an electric signal from the image element 3 is used as measurement data of the reflection spectrum. A central control device (CPU) 4 and a storage device 5 that stores the previously acquired reflection spectrum data of the measurement object M as reference data are provided.

  The freshness sensor S1 determines the freshness of the measurement object M on the basis of the measurement data and the reference data from the storage device 5 in the central control device 4. In addition to the above configuration, the central control device 4 A display device 6 for displaying the obtained freshness determination result and an external output terminal 7 for outputting the freshness determination result obtained by the central control device 4 are provided.

  As the light source 1, illumination that continuously generates constant light, a strobe that instantaneously generates constant light, or the like can be used.

  The spectroscope 2 includes a condensing lens 8, a slit plate 9 having a slit 9 a, and a diffraction unit 10. The spectroscope 2 divides the reflected light from the measurement object M to each wavelength region including the near infrared region. A reflection spectrum in which (color bands) are arranged in order is formed. This reflection spectrum is received by the image element 3 through the imaging lens 11.

  The image element 3 has a large number of pixels arranged in the X and Y directions. In this embodiment, an artificial retina LSI having a projection calculation function is used. When receiving the reflection spectrum, the image element 3 is in a state in which light intensity proportional to the reflection intensity density composed of a matrix of wavelengths (X axis) and slit width direction positions (Y axis) is distributed. The light intensity is converted into an electric signal (voltage), and at the same time, the electric signal averaging process at least in the Y-axis direction can be performed in an analog manner by the projection calculation function.

  The central control device 4 uses the electrical signal from the image element 3 as reflection spectrum measurement data, and compares this measurement data with reference data from the storage device 5. At this time, the measurement data of the reflection spectrum is a pattern indicating the relationship between the wavelength and the reflectance, and the entire pattern or a characteristic part of the pattern is used in comparison with the reference data.

  Therefore, a pattern indicating the relationship between the wavelength and the reflectance is used as the reference data of the storage device 5 as in the case of the measurement data. However, when a part of the pattern is used as the measurement data, a predetermined value is used as the reference data. It is also possible to set a threshold value.

  Further, the central control device 4 performs freshness determination based on the measurement data and the reference data. More specifically, the pattern recognition result, that is, the freshness of the measuring object M is graded and output to the display device 6, and an appropriate code such as a number is displayed on the display device 6.

  Here, the measuring object M whose freshness decreases with the passage of time is mainly fresh food. Among these fresh foods, raw meat, for example, has the property of absorbing light mainly in the blue wavelength range and emitting fluorescence in the wavelength range from red to the near infrared, and the pattern of the reflection spectrum over time. Changes. In addition, plants such as vegetables have a strong correlation between the reflection spectrum of chlorophyll (green) and the freshness, and the pattern of the reflection spectrum changes with time as shown in FIGS.

  FIG. 2 is a graph showing changes in the pattern of the reflection spectrum over time when cucumber is used as the measurement object M. FIG. In this case, in the initial stage when the freshness is good, a high reflectance is obtained in the wavelength region of 750 to 800 nm, but it can be seen that the reflectance in the same wavelength region decreases with time.

  FIG. 3 is a graph showing changes in the pattern of the reflection spectrum over time when a banana is used as the measurement object M. FIG. In this case, in the initial stage when the freshness is good, a high reflectance is obtained in the wavelength region of 550 to 800 nm, but it can be seen that the reflectance in the same wavelength region decreases with time.

  FIG. 4 is a graph showing the change in the pattern of the reflection spectrum with the passage of time when the plum is the measurement object M. In this case, in the initial stage when the freshness is good, a high reflectance is obtained in the wavelength region of 600 to 800 nm, and in particular, the reflectance is low in the vicinity of 660 nm. Can be seen to decrease.

  When plants such as vegetables are used as the measurement object M, the reflectance decreases with the passage of time as described above because the surface gradually becomes dark and the water content decreases as is well known. . Even when raw meat, raw fish, or the like is the measurement object M, the pattern of the reflection spectrum changes with time.

  Therefore, in the freshness sensor S1, for example, an initial (first day) reflection spectrum pattern shown in FIGS. 2 to 4 is stored in the storage device 5 as reference data, and when actually measured, In the central controller 4, the measurement data, which is a reflection spectrum pattern from the image element 3, is compared with the reference data. Thereby, the freshness of the measuring object M can be determined from the degree of decrease in reflectance.

  The central control device 4 grades freshness in the following manner. For example, as shown in FIG. 4, when the plum is the measurement object M, three wavelength regions A (460 to 510 nm), B (570 to 650 nm), and C (740 to 800 nm) are selected from the reflection spectrum pattern. The moisture index and freshness index are obtained based on the following formula.

Moisture index: (C + A) / 10 (C-B)
Freshness index: (C + B) / 10 (C-B)

  Then, in the central control unit 4, as shown in FIG. 5, based on the above moisture index and freshness index, the case where it is evaluated as fresh is regarded as equal first grade, and the case where it is evaluated that freshness starts to fall is regarded as equal second grade The case where it is evaluated as rotting is classified as the third grade, and these grades are selected and displayed on the display device 6.

  In this way, the freshness sensor S1 forms a reflection spectrum by splitting the reflected light from the measurement object M, and uses the reflection spectrum data as measurement data, as well as the previously acquired reflection spectrum of the measurement object M. Since the data is used as reference data, and the freshness of the measurement object M is determined based on the measurement data and the reference data, the freshness of the measurement object M can be determined nondestructively and in a very short time.

  The freshness sensor S1 eliminates the need for a large-scale analytical instrument as compared with the conventional freshness determination in which chemical analysis is performed, and it is easy to cope with downsizing of the apparatus, and samples are collected. Therefore, it is very easy to inspect all products in real time at the site where fresh foods are handled.

  In addition, since the freshness sensor S1 includes the light source 1, it is possible to keep the reflection spectrum formation condition constant by keeping the amount of light irradiating the measurement object M constant. Since the artificial retina LSI is used for the image element 3 and the averaging process of the electric signal in the Y-axis direction is performed in an analog manner, the load on the central control device 4 is reduced, and the small and low-power central control device 4 is provided. Even if it is used, the calculation processing time can be performed in a short time.

  Further, since the freshness sensor S1 can output the freshness determination result from the central control device 4 to the outside from the external output terminal 7, the interface with the external device is easy, and the data is incorporated into various electronic devices. The range of application can be expanded, such as forwarding.

  At this time, the external output terminal 7 can be wired or wirelessly interfaced with an external device, and has an input terminal for inputting reference data to the storage device 5 from the outside. It is also possible.

  FIG. 6 is a diagram for explaining another embodiment of the freshness sensor according to the present invention.

  The illustrated freshness sensor S2 includes a light source 1, a spectroscope 2, an image element 3, a central control device 4, a storage device 5, a display device 6, an external output terminal 7, and an imaging lens 11 provided on a multilayer electronic substrate. It has become.

  In this embodiment, first to fourth substrates P1 to P4 are provided. On the first substrate P1, a condensing lens 8 constituting the light source 1 and the spectroscope 2 is provided. The second substrate P2 is provided with a diffraction section 10 that constitutes the spectrometer 2, and a slit plate 9 that constitutes the spectrometer 2 is disposed between the first substrate P1 and the second substrate P2. . Further, the imaging lens 11 is provided on the third substrate, and the image element 3, the central control device 4, the storage device 5, the display device 6, and the external output terminal 7 are provided on the fourth substrate P4. .

  The freshness sensor S2 having the above-described configuration can obtain the same operations and effects as those of the previous embodiment, and can further improve the versatility by making the entire apparatus more compact. It can be easily incorporated into portable electronic terminal devices including telephones and storage devices such as refrigerators and cooler boxes.

  In addition, when incorporated in a mobile phone, a part of the configuration can be used in combination with an existing camera function. For example, the slit plate 9, the second and third substrates P2, P3 can be slid, Switching between normal shooting and freshness determination may be performed.

  It should be noted that the freshness sensor according to the present invention is not limited to the details of the configuration described above, and the configuration can be changed as appropriate without departing from the gist of the present invention.

It is explanatory drawing which shows one Example of the freshness sensor concerning this invention. It is a graph which shows a time-dependent change of the reflection spectrum at the time of setting cucumber as a measuring object. It is a graph which shows a time-dependent change of the reflection spectrum at the time of setting a banana as a measuring object. It is a graph which shows a time-dependent change of the reflection spectrum at the time of using a plum as a measuring object. It is a graph explaining freshness evaluation at the time of using a plum as a measuring object. It is explanatory drawing which shows the other Example of the freshness sensor concerning this invention.

Explanation of symbols

M measurement object P1 to P4 Substrate S1 S2 Freshness sensor 1 Light source 2 Spectrometer 3 Image element 4 Central controller 5 Storage device 7 External output terminal

Claims (6)

  A freshness sensor for a measurement object whose freshness decreases with time, a spectroscope that divides the reflected light from the measurement object to form a reflection spectrum, and receives the reflection spectrum from the spectroscope to receive electricity An image element for converting into a signal; a central control unit that uses the electrical signal from the image element as reflection spectrum measurement data; and a storage device that stores the reflection spectrum data of the measurement object acquired in advance as reference data. A freshness sensor characterized in that a freshness determination of a measurement object is performed based on measurement data and reference data from a storage device in a control device.   The freshness sensor according to claim 1, further comprising a light source that emits light to the measurement object.   The freshness sensor according to claim 1 or 2, wherein the image element is an artificial retina LSI having a projection calculation function.   The freshness sensor according to any one of claims 1 to 3, further comprising an external output terminal that outputs a freshness determination result obtained by the central control device.   The freshness sensor according to any one of claims 1 to 4, wherein the spectroscope, the image element, the central control device, and the storage device are provided on a multilayer electronic substrate.   When determining the freshness of a measurement object whose freshness decreases with time, the reflected light from the measurement object is dispersed to form a reflection spectrum, and this reflection spectrum data is used as measurement data. A freshness determination method characterized by using the acquired reflection spectrum data of a measurement object as reference data, and determining the freshness of the measurement object based on the measurement data and the reference data.

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