Fruit water core diagnostic method based on visible and near infrared spectrum characteristic wave bands
Technical field
The present invention relates to utilize optical instrument to come the method for analysis of material, especially relate to a kind of fruit water core diagnostic method based on visible and near infrared spectrum characteristic wave bands.
Background technology
Near infrared spectrum is meant the electromagnetic wave of wavelength at 780~2526nm, between visible region and mid-infrared light district.Because the sum of fundamental frequencies that contains hydrogen group (C-H, N-H) vibration near infrared spectrum district and the organic molecule and the absorption of frequencys multiplication at different levels are consistent, so the near infrared spectrum by scanning samples, can obtain the eigen vibration information that organic molecule in the sample contains hydrogen group.Compare with traditional chemical analysis method, the major technique characteristics of near-infrared spectrum technique are: analysis speed is fast, and simultaneous determination of multiponents, sample do not need pre-service, non-destructive analysis, and long distance is measured and real-time analysis, harmonic analysis cost and simple to operate.
As seen in the check and analysis of agricultural product and food, obtained using widely with near-infrared spectrum technique.In the fruit context of detection, people such as lammertyn utilize visible spectrum and near infrared spectrum to detect apple acidity, hardness and soluble solid content, and combine with the analysis that routinizes, and have set up the quantitative math-model of prediction apple sugar content and acidity.People such as McGlone utilize the 500-1100nm spectral range to detect Royal Gala apple internal composition---starch, soluble solid and acidity.People such as Lu utilize near infrared spectrum to detect Empire and Delicious apple hardness and pol, by spectrum is handled, and combine with the physico-chemical analysis of routine, have set up the mathematical model of prediction apple sugar content and acidity.Less relatively in research to the fruit water core.
Yet visible and the near infrared spectrum regional extent is bigger, though have now much be used for measuring whole as seen and the spectrometer of near infrared spectrum regional extent, these equipment are all bigger, are unfavorable for portable measurement.By discovering, existence can reflect the several features wave band of fruit water core degree, and its spectral information changes closely related with the water core degree.Therefore can objectively reflect the water core gradient of infection by the spectral information of measuring these characteristic wave bands, and not be subjected to the influence of other factors.Based on a large amount of tests, obtain the several features wave band of reflection water core degree in visible and near infrared spectrum zone, thereby design portable set based on microcontroller embedded system.By detecting the characteristic wave bands reflectivity information that these light sensors obtain, adopt simple homing method to replace chemometrics method to carry out modeling.Portable water core degree detecting instrument is made in the embedding of implementation model algorithm in single-chip microcomputer.
Summary of the invention
The object of the present invention is to provide a kind of fruit water core diagnostic method based on visible and near infrared spectrum characteristic wave bands, can gather the reflectivity information of tested fruit internal characteristic wave bands quickly and accurately, analysis obtains tested fruit water core gradient of infection, thereby realizes the fruit water core diagnostic system of real non-destructive.
The technical solution used in the present invention is that the step of this method is as follows:
1) probe with instrument shines tested fruit, by the fruit internal spectral reflectivity information on the light sensor acquisition characteristics wave band of instrument;
2) the fruit internal reflective information that collects is removed noise by data line through signal conditioning circuit, A/D converter input single-chip microcomputer;
3) the water core diagnostic routine inputs to the water core spectral model with the spectral reflectivity information that obtains, by the calculating of model, and output water core diagnostic result;
4) diagnostic result of LCD display output fruit water core.
The foundation of described water core spectral model may further comprise the steps:
1) obtains to reflect the several features wave band of water core gradient of infection by test.
2) set up water core spectral model between these characteristic wave bands spectral reflectance information and the water core gradient of infection.
Compare with traditional water worry detection means, the beneficial effect that the present invention has is:
(1) utilize spectral technique to carry out the water core diagnosis, as long as can find several spectral signature wave bands that can reflect the water core degree, thinking of the present invention can be applied to quick, accurate, stable, real-time, the nondestructive diagnosis of fruit water core.
(2) reduce the detection cost, accelerate analysis speed, reduce labor intensity, and can can't harm discriminating, need not destroy fruit analyzing samples.
(3) because the water core of system detects is the whole spectral informations that give several features wave band rather than whole visible and near infrared spectrum.Therefore need not to give calculated amount big chemometrics method, program is simple, can write to embed in the single-chip microcomputer.
(4) whole detection system is a portable system that has the embedded scm of several light sensors and LED lamp, is easy to carry about with one.
Description of drawings
Fig. 1 is a service system block diagram of the present invention.
Fig. 2 is the software flow pattern of system of the present invention.
Embodiment
As shown in Figure 1, a kind of fruit water core diagnostic system based on visible and near infrared spectrum characteristic wave bands comprises a portable system that has the embedded scm of several light sensors and LED lamp.System is the damascene structures of microcontroller with the single-chip microcomputer, with signal conditioning circuit signal of sensor is carried out filtering, the processing of amplification etc., make signal meet the input requirement of A/D converter, A/D converter in the system is realized the conversion of simulating signal to digital signal, uses for single-chip microcomputer, and keyboard is realized the input of external command in the system, the operation of control instrument, LCD display output water core diagnostic result.
With the probe irradiation fruit surface of instrument, the light sensor in the probe can be gathered the spectral reflectivity of the several features wave band that can reflect fruit water core degree in real time.Use the LED lamp as light source in the probe, by data line input single-chip microcomputer, the spectral analysis process software is analyzed the spectral information of water core in various degree.Obtain fruit water core gradient of infection by the water core spectral analysis program that embeds in the single-chip microcomputer.
The spectral measurement of system of the present invention is simple, only needs the tested fruit surface of system's probe irradiation can be carried out the detection of water core degree.
As shown in Figure 2, the water core spectral model in the water core spectral analysis process software is established as foundation, just sets up in the software development stage, may further comprise the steps:
1) acquisition correction sample set spectral information.Adopt the demarcation blank that the spectral information of gathering is demarcated before the spectral measurement.Concentrate the spectral reflectivity information of all band (400-2500nm) of fruit then by visible and near infrared spectrometer acquisition correction.
2) the spectrum pre-service of reflection water core gradient of infection.Because the original spectrum information that collects has certain noise, so adopt methods such as convolution is level and smooth, standardization, polynary scatter correction, differentiate, small echo to carry out the spectrum pre-service.
3) set up the spectrum correction model of fruit water core gradient of infection.The fruit that calibration samples is concentrated carries out the gradient of infection assessment of each fruit water core after gathering reflective information through visible and near infrared spectrometer through the water core diagnostic criteria.And set up the mathematical model of pretreated spectral reflectance information and water core gradient of infection by chemometrics method.Comprise: principal component regression, partial least squares regression, neural network model etc.
4) obtain to reflect the several features wave band of water core gradient of infection by a large amount of tests.By analyzing each wave band, select the big minority wave band of contribution rate to substitute whole spectral band in contribution rate to reflection water core gradient of infection.
5) by chemometrics method, set up the relational model between these characteristic wave bands spectral reflectivity information and the water core gradient of infection.Database model has good robustness and adaptability, can carry out practical application.
As shown in Figure 2, water core spectral analysis process software may further comprise the steps in actual applications:
1) by the fruit internal spectral reflectivity information on the light sensor acquisition characteristics wave band of instrument.
2) the water core diagnostic routine inputs to the water core spectral model with the spectral reflectivity information that obtains.By the calculating of model, output water core gradient of infection.
3) LCD display output water core degree diagnostic result.