CN104089892A - Meat freshness detection system and method - Google Patents

Abstract

The invention relates to a meat freshness detection system and a detection method to solve the problems of subjective and inaccurate detection of beef freshness and complex detection process of detection equipment in the prior art. The system comprises a seat body, the seat body is provided with a bracket, and an irradiation light source is arranged above the bracket. The irradiation light source is rotatably connected to an adjustment mechanism for adjusting the position of the irradiation light source, and the adjustment mechanism is installed on the seat body. A receiving mechanism is disposed below the bracket, and a control unit is disposed in the seat body and is in connection with the irradiation light source, the adjustment mechanism and the receiving mechanism. By analyzing sample reflection or transmission spectrum data, the beef freshness can be judged. By adopting the spectrum detection mode, nondestructive detection can be carried out on samples. The device structure is simple, the operation is fast and simple, and the detection data are accurate.

Description

A kind of identifying meat freshness system and method

Technical field

The present invention relates to a kind of food inspection field, especially relate to a kind of simple in structure, operate fast and convenient, detect identifying meat freshness system accurately, and the detection method of this system.

Background technology

Consumption of meat is an important component part of food consumption always, is that consumers in general are than preferable food.In recent years, the transformation of people's philosophy of life, health perception constantly strengthens, quality and health conditions requiring to meat product are more and more stricter, the safety of meat product, concerns common people's life security and social stability, controls meat product quality and just becomes in daily life more and more important.At present the detection technique of freshness of meat is had to organoleptic detection, physics and chemistry detection etc.Organoleptic detection is often evaluated the impact of the factors such as expert's experience, psychology and physiology, different teacher of the evaluating is due to impacts such as its hobby, mood, sex and sense organ sensitivity, may be difficult to obtain consistent evaluation result, therefore the accuracy of evaluation result is often difficult to ensure.Physics and chemistry detects needs a series of equipment and device to complete, process complexity, and detection time is long, and equipment is also complicated.Also have in recent years in addition some scholars to develop gas-chromatography detection method, although detection sensitivity is also fine, this detection method damages.Therefore wish a kind of Apparatus and method for that can quick, easy, accurate Non-Destructive Testing freshness of meat, in an orderly manner meat is detected in time, to guarantee the safety of meat product.

Summary of the invention

The present invention solves identifying meat freshness to be existed in prior art subjective inaccurately, and has the problem of checkout equipment testing process complexity, provide a kind of simple in structure, operate fast and convenient, detect identifying meat freshness system accurately.

The present invention also provide a kind of operation fast and convenient, detect identifying meat freshness method accurately.

Above-mentioned technical matters of the present invention is mainly solved by following technical proposals: a kind of identifying meat freshness system, comprise pedestal, on pedestal, be provided with the bracket for placing sample, above bracket, be provided with radiation source, described radiation source is rotatably connected on the adjusting mechanism of adjusting radiation source position, adjusting mechanism is arranged on pedestal, below bracket, be provided with receiving mechanism, control module is set in pedestal, and control module is connected with radiation source, adjusting pole, receiving mechanism;

Radiation source: transmitting detects light beam to sample, and can receive the reflected light information on sample, feeds back to control module;

Receiving mechanism: remain with radiation source and align, receive the transmitted light of radiation source, and feed back to control module;

Control module: control radiation source, adjusting mechanism, receiving mechanism work, according to the spectral information of radiation source or receiving mechanism feedback, calculate sample signal to noise ratio (S/N ratio) by accidental resonance analysis meter, and with drawing sample freshness information after tables of data.

System of the present invention detects freshness of meat by spectral analysis, can detect quicker, easy, accurately freshness of meat.Radiation source is used for launching detecting light beam, also can receive irreflexive light on sample simultaneously.This radiation source is rotatably connected on adjusting mechanism, and radiation source can be rotated around axle, and adjusting mechanism can be rotated and highly regulate simultaneously, makes like this radiation source irradiation position can all cover sample.Receiving mechanism is for the transmitted light of receiving beam on sample, and in the time that radiation source irradiation position changes, receiving mechanism also will be adjusted position and remain with radiation source and align.Radiation source, adjusting mechanism, receiving mechanism all feed back to control module by information, and control module is according to their work of their information control.Control module also will carry out analytical calculation to the spectral information detecting simultaneously, draw snr value, in control module, also store the each freshness standard value of pre-set meat tables of data, by with the snr value calculating after draw sample freshness.Radiation source adopts Halogen lamp LED or generating laser.This device can can't harm meat is detected, and the scene that is applicable to is detected meat in enormous quantities.

As a kind of preferred version, between described radiation source and control module, be connected with control circuit for light source, control circuit for light source comprises keyboard, input block, function memory and power amplifier unit, described keyboard connects input block, input block contiguous function storer, function memory is connected with power amplifier unit, and power amplifier unit is connected with radiation source, and power amplifier unit is connected with control module.This input block is 8 pin input interfaces, and keyboard is connected with 8 pin input interfaces, and 8 pin input interface function storeies connect, and function memory is AT24C02 chip, for storing the function information from keyboard input.Power amplifier unit includes single chip computer AT 89C2051, three-terminal voltage-stabilizing pipe LM7805, the passive crystal oscillator of relay J RC4100,11.0592MHz, LED fluorescent tube.Arrive power amplifier by keyboard input function through function memory, controller changes according to input function by power amplifier unit control radiation source intensity.

As a kind of preferred version, described receiving mechanism includes receiver, slide and swingle, described slide is the arcuate structure taking radiation source rotating shaft as the center of circle, on slide, offer chute, described receiver is arranged in chute, on chute two side, be provided with gathering sill, on receiver both sides, correspondence is provided with angle sheave, gathering sill is provided with the gear teeth, angle sheave is arranged in gathering sill, and angle sheave is gear, and angle sheave is meshed and is connected with gathering sill, slide is fixed on swingle upper end, and swingle rotates and is arranged on pedestal.Receiver is used for receiving transmitted ray, this receiver will keep aliging with radiation source, in the time that radiation source moves, thereby by controlling angle sheave rotation, receiver is moved, because this slide is the arcuate structure taking radiation source rotating shaft as the center of circle, therefore mobile receiver can make receiver keep aliging with radiation source.This swingle can drive slide to be rotated, and in the time that radiation source is rotated, by controlling swingle synchronous rotary, makes receiver keep keeping aliging with radiation source.

As a kind of preferred version, in described receiver, be provided with the drive motor of output shafts, two output shafts of drive motor are connected with angle sheave respectively, connect the first motor that drives swingle to rotate in described swingle lower end, drive motor and the first motor are connected on control module, on receiver bottom, are provided with roller.Drive motor drives angle sheave to rotate, and receiver is moved.The first motor drives swingle to rotate.All controlled unit controls of drive motor and the first motor, control module is according to radiation source rotation information, and corresponding control slide rotates and receiver moves, and keeps receiver and radiation source to align.

As a kind of preferred version, described adjusting mechanism comprises first body of rod, second body of rod, rotary screw and guide pole, first body of rod vertically arranges, described radiation source is connected to by rotating shaft on the lower end of first body of rod, rotating shaft is connected with the second motor that driver rotates, the first body of rod upper end is through on clutch shaft bearing, be provided with the 3rd motor on bearing top, the 3rd motor output shaft is connected with the first body of rod upper end, described second body of rod and the perpendicular setting of first body of rod, the second lever front end is fixed on clutch shaft bearing, be disposed with thread bush and orienting sleeve in the second body of rod rear end, described rotary screw and guide pole are arranged side by side on pedestal, thread bush and orienting sleeve are nested with respectively on rotary screw and guide pole, be connected with the 4th motor in rotary screw lower end, rotary screw upper end connects the second bearing, guide pole upper end and the second bearing fix, the second motor, the 3rd motor and the 4th motor are connected on control module.This adjusting mechanism can be rotated first body of rod, can adjust the height of second body of rod simultaneously, thereby regulates the irradiation position of radiation source.The vertical insertion of rotating shaft is arranged on the first lever front end, rotating shaft front end is fixed on radiation source centre position, the second motor output shaft parallels with rotating shaft, and the second motor output shaft is aimed at rotating shaft rear end and is fixedly connected with it, the second Electric Machine Control radiation source rotational angle.The 3rd motor output shaft is parallel with second body of rod, and the 3rd motor output shaft is connected to the second body of rod upper end, makes second body of rod along its axis rotation.The 4th driven by motor screw mandrel rotation, screw mandrel rotation can drive cover thread bush thereon to move up and down, thereby makes the second body of rod oscilaltion, and orienting sleeve is enclosed within on guide pole, second body of rod is remained and do not rock and remain on lifting in same vertical plane.

A kind of identifying meat freshness method, comprises the following steps:

Step 1: detect in advance the volatile base nitrogen value of different resting period meat samples, obtain the freshness of meat threshold value corresponding with radiation source position with some groups;

Step 2: prepare meat sample, sample is placed on bracket, radiation source adopts the position identical with step 1 to be radiated on sample, then radiation source intensity decline according to sinusoidal curve according to tangent cutve increase during the course, control module collection reflection or transmittance spectra data, then adjust radiation source irradiation position, reflection or transmittance spectra data at the some variant points of sample collection like this; In this step to the anglec of rotation of its radiation source of sample detection with in step 1, obtain freshness of meat threshold operation in the anglec of rotation of radiation source respectively corresponding.

Step 3: by each check point spectroscopic data substitution accidental resonance model, by accidental resonance model being carried out to single order and second order differentiate, and single order accidental resonance model is passed through to quadravalence jade for asking rain Ge Kuta algorithm, calculate each check point signal to noise ratio (S/N ratio) output valve;

Step 4: each check point signal to noise ratio (S/N ratio) output valve freshness threshold value corresponding with it compared and draw each check point signal to noise ratio (S/N ratio) output error value, then each signal to noise ratio (S/N ratio) output error value is carried out to statistic of classification, whether judgement sample is fresh.

As a kind of preferred version, in step 1, detect in advance the volatile base nitrogen TVB-N value of different resting period meat samples, obtain the freshness of meat threshold value SNR corresponding with the radiation source anglec of rotation with some groups _thre1, SNR _thre2..., SNR _threi, i=1 ... m, m is check point quantity.

As a kind of preferred version, in step 3, by the each spectroscopic data difference substitution accidental resonance model gathering, its formula is as follows,

Wherein for input matrix, comprise periodically sinusoidal signal spectral measurement signal Spect (t), and in grasp noise N (t), A is signal amplitude, f is signal frequency, and D is external noise intensity, and ξ (t) is external noise, x (t) is Brownian movement Particles Moving lopcus function, and t is run duration;

Accidental resonance model is carried out to single order and second order differentiate is that V (x, t) carries out single order and second order differentiate for x, and to make its equation be 0, obtain formula and be,

Set noise intensity D=0, spect (t)=0, N (t)=0, the critical value that B=1 tries to achieve cyclical signal is

By A _cin substitution first derivation function, establish X ₀(t)=0, sn ₀=0;

With quadravalence jade for asking rain Ge Kuta Algorithm for Solving single order accidental resonance model, obtain:

$x_{n+1}\left(t\right)=x_n\left(t\right)+1/6[{\left(k_1\right)}_n+(2-\sqrt{2}){\left(k_2\right)}_n+(2+\sqrt{2}){\left(k_3\right)}_n+{\left(k_4\right)}_n]$

And calculate

${\left(k_1\right)}_n=4({\mathrm{ax}}_{n-1}\left(t\right)-{\mathrm{bx}}_{n-1}^3\left(t\right)+{\mathrm{sn}}_{n-1})$

${\left(k_2\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})}^3+{\mathrm{sn}}_{n-1}]$

${\left(k_3\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_2\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{\sqrt{2}-1}{2}{\left(k_1\right)}_{n-1}+\frac{2-\sqrt{2}}{2}{\left(k_2\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

${\left(k_4\right)}_n=4[a(x_{n-1}\left(t\right)+{\left(k_3\right)}_{n-1})-b{(x_{n-1}\left(t\right)-\frac{\sqrt{2}}{2}{\left(k_2\right)}_{n-1}+\frac{2+\sqrt{2}}{2}{\left(k_3\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

Wherein x _nfor the n order derivative value of x (t), sn _nbe the n order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1, a, b are the constant of setting, and calculate x ₁(t), x ₂(t) ..., x _n+1(t) value;

To x ₁(t), x ₂(t) ..., x _n+1(t) carry out integration, obtain x (t), and obtain the position x of x (t) in the double-deck stochastic system generation accidental resonance moment of single order and second order differentiate function composition _mvalue and x _mcorresponding resonance moment t1 and with the corresponding noise D1 of t1, D1 is a value in D; D is a function with 0.01 stepping in [0,1] scope, has known the t1 moment, and D1 has just determined.

Then pass through formula

$\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\ΔU}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\ΔU}\right)}^2/D_1}$

The signal to noise ratio (S/N ratio) of calculating each spectroscopic data output, obtains SNR ₁, SNR ₂..., SNR _i, wherein Δ U=a ²/ 4b.In Practical Project is measured, the data of measurement comprise echo signal and interference noise conventionally, if echo signal is covered by strong background noise, we cannot accurately detect.Under the help of accidental resonance, inside grasp the weakened echo signal feeble signal of noise and effectively amplified, echo signal is likely caught in.Sometimes because echo signal is too faint and ground unrest is too strong, individual layer accidental resonance can not effectively reduce system noise, therefore just individual layer accidental resonance output signal again need to be delivered in lower one deck stochastic resonance system and analyzed, the object that so finally realize target feeble signal is measured.

As a kind of preferred version, in step 4, output signal-to-noise ratio error is that each check point output signal-to-noise ratio is calculated with the freshness threshold value of corresponding check point, and its formula is

${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\×100\%.$

As a kind of preferred version, the process of adding up in step 5 meets QE for calculating _ithe number of≤5% output signal-to-noise ratio error, is designated as M ₁, calculate and meet QE _ithe number of the output signal-to-noise ratio error of >5%, is designated as M ₂if, make the judgement that sample is fresh, if make the stale judgement of sample, if all otherwise return to step 2 and sample is detected again and carry out data processing.

As a kind of preferred version, the testing process of freshness of meat threshold value is: the total volatile basic nitrogen numerical value that detects a meat every day, until the total volatile basic nitrogen numerical value of certain day sample exceeds standard for the first time, this day sample carried out to the operation of step 2 to step 3, the signal to noise ratio (S/N ratio) output obtaining is freshness threshold value, when detection, started by radiation source position for the first time, detect each time afterwards, radiation source angle increases by 5 degree.

Therefore, advantage of the present invention is: adopt spectral detection mode, can carry out Non-Destructive Testing to sample; Apparatus structure is simple, it is fast and convenient to operate, it is accurate to detect data.

Brief description of the drawings

Accompanying drawing 1 is a kind of structural representation of apparatus of the present invention;

Accompanying drawing 2 is a kind of structural representations of receiving mechanism in apparatus of the present invention;

Accompanying drawing 3 is a kind of cross-sectional view of receiving mechanism slide in the present invention;

Accompanying drawing 4 is the connecting frame schematic diagram between control module and receiving mechanism in the present invention, adjusting mechanism;

Accompanying drawing 5 is a kind of schematic flow sheets of method in the present invention;

Accompanying drawing 6 is a kind of frame diagrams of control circuit for light source of the present invention;

Accompanying drawing 7 is a kind of waveform schematic diagram of radiation source Strength Changes in the present invention.

1-pedestal 2-bracket 3-radiation source 4-adjusting mechanism 5-receiving mechanism 6-receiver 7-slide 8-swingle 9-chute 10-gathering sill 11-angle sheave 12-control module 13-drive motor 14-first motor 15-second motor 16-the 3rd motor 17-the 4th motor 18-first body of rod 19-second body of rod 20-rotary screw 21-guide pole 22-rotating shaft 23-clutch shaft bearing 24-thread bush 25-orienting sleeve 26-the second bearing 27-roller 28-keyboard 29-input block 30-function memory 31-power amplifier unit

Embodiment

Below by embodiment, and by reference to the accompanying drawings, technical scheme of the present invention is described in further detail.

Embodiment:

A kind of identifying meat freshness system of the present embodiment, as shown in Figure 1, comprises pedestal 1, is provided with the bracket 2 for placing sample on pedestal, and bracket is connected on pedestal by support column.Above bracket, be provided with radiation source 3, on pedestal, be provided with the adjusting mechanism 4 of adjusting radiation source position, radiation source is rotatably connected on adjusting mechanism 4, below bracket, be provided with receiving mechanism 5, control module 12 is set in pedestal, and control module is connected with radiation source, adjusting pole, receiving mechanism.As shown in Figure 6, between radiation source 3 and control module 12, be connected with control circuit for light source, control circuit for light source comprises keyboard 28, input block 29, function memory 30 and power amplifier unit 31, keyboard connects input block, input block contiguous function storer, function memory is connected with power amplifier unit, and power amplifier unit is connected with radiation source, and power amplifier unit is connected with control module.

As shown in Figures 2 and 3, receiving mechanism 5 includes receiver 6, slide 7 and swingle 8, slide is the arcuate structure taking radiation source rotating shaft as the center of circle, on slide, have and be provided with chute 9, receiver mobile link is in chute, on chute two side, be provided with gathering sill 10, on receiver both sides, correspondence is provided with angle sheave 11, gathering sill is provided with the gear teeth, angle sheave is arranged in gathering sill, and angle sheave is gear, and angle sheave is meshed and is connected with gathering sill, receiver is provided with roller 27 on bottom, and roller contacts with chute bottom.In receiver, be provided with the drive motor 13 of output shafts, two output shafts of drive motor are connected with angle sheave 11 respectively.Slide is fixed on swingle upper end, and swingle rotates and is arranged on pedestal 1, and swingle lower end connects the first motor 14 that drives swingle to rotate, and drive motor and the first motor are connected on control module 12.

As shown in Figure 1, adjusting mechanism 4 comprises first body of rod 18, second body of rod 19, rotary screw 20 and guide pole 21, first body of rod vertically arranges, radiation source 3 is connected to by rotating shaft 22 on the lower end of first body of rod, rotating shaft is connected with the second motor 15 that driver rotates, the first body of rod upper end is through on clutch shaft bearing 23, be provided with the 3rd motor 16 on bearing top, the 3rd motor output shaft is connected with the first body of rod upper end, second body of rod and the perpendicular setting of first body of rod, the second lever front end is fixed on clutch shaft bearing, be disposed with thread bush 24 and orienting sleeve 25 in the second body of rod rear end, rotary screw and guide pole are arranged side by side on pedestal, thread bush and orienting sleeve are nested with respectively on rotary screw and guide pole, be connected with the 4th motor 17 in rotary screw lower end, rotary screw upper end connects the second bearing 26, guide pole upper end and the second bearing fix, the second motor, the 3rd motor and the 4th motor are connected on control module 12.

Adjusting mechanism control radiation source position, radiation source can be rotated around the shaft under the second Electric Machine Control, controls radiation source irradiating angle.First body of rod can pivot under the 3rd Electric Machine Control, adjusts planar 360 degree rotations of radiation source, and rotary screw can be adjusted the second body of rod oscilaltion, adjusts the position of radiation source at height.Receive swingle in structure and rotated by the first Electric Machine Control, the control module control first motor anglec of rotation is the same with the 3rd motor anglec of rotation, makes first body of rod anglec of rotation the same with the slide anglec of rotation, makes the receiver radiation source that can align all the time.Drive motor drives receiver to move, and this receiver will keep aliging with radiation source, and receiver, when mobile, once receive the transmitted light of radiation source, stops moving, and now receiver and radiation source align.

As shown in Figure 5, identifying meat freshness method comprises the following steps:

Step 1: detect in advance the volatile base nitrogen value of different resting period meat samples, obtain the freshness of meat threshold value corresponding with radiation source position with some groups.It is specially the total volatile basic nitrogen TVB-N value that detects a meat every day, until the total volatile basic nitrogen numerical value of certain day sample exceeds standard for the first time, this day sample carried out to the operation of following steps two to step 3 in advance, the signal to noise ratio (S/N ratio) output SNR of each check point now obtaining _thre1, SNR _thre2..., SNR _threi, i=1 ... m, is freshness threshold value, and m is check point quantity, when detection, is started by radiation source position for the first time, detects each time afterwards, and radiation source angle increases by 5 degree.

Step 2: prepare meat sample, beef sample thickness is 15mm-20mm, this enforcement in example, adopt the sample of 18mm thickness.sample is placed on bracket, radiation source adopts the position identical with step 1 to be radiated on sample, as shown in Figure 7, then radiation source intensity decline and change according to sinusoidal curve according to tangent cutve increase during the course, control module collection reflection or transmittance spectra data, then adjust radiation source irradiation position, reflection or transmittance spectra data at the some variant points of sample collection like this;

Step 3: by each check point spectroscopic data substitution accidental resonance model, by accidental resonance model being carried out to single order and second order differentiate, and single order accidental resonance model is passed through to quadravalence jade for asking rain Ge Kuta algorithm, calculate each check point signal to noise ratio (S/N ratio) output valve.

In the each spectroscopic data difference substitution accidental resonance model gathering, its formula is as follows,

Wherein for input matrix, comprise periodically sinusoidal signal spectral measurement signal Spect (t), and in grasp noise N (t), A is signal amplitude, f is signal frequency, and D is external noise intensity, and ξ (t) is external noise, x (t) is Brownian movement Particles Moving lopcus function, and t is run duration.

Accidental resonance model is carried out to single order and second order differentiate is that V (x, t) carries out single order and second order differentiate for x, and to make its equation be 0, obtain formula and be,

Set noise intensity D=0, spect (t)=0, N (t)=0, the critical value that B=1 tries to achieve cyclical signal is

By A _cin substitution first derivation function, establish X ₀(t)=0, sn ₀=0;

With quadravalence jade for asking rain Ge Kuta Algorithm for Solving single order accidental resonance model, obtain:

$x_{n+1}\left(t\right)=x_n\left(t\right)+1/6[{\left(k_1\right)}_n+(2-\sqrt{2}){\left(k_2\right)}_n+(2+\sqrt{2}){\left(k_3\right)}_n+{\left(k_4\right)}_n]$

And calculate

${\left(k_1\right)}_n=4({\mathrm{ax}}_{n-1}\left(t\right)-{\mathrm{bx}}_{n-1}^3\left(t\right)+{\mathrm{sn}}_{n-1})$

${\left(k_2\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})}^3+{\mathrm{sn}}_{n-1}]$

${\left(k_3\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_2\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{\sqrt{2}-1}{2}{\left(k_1\right)}_{n-1}+\frac{2-\sqrt{2}}{2}{\left(k_2\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

${\left(k_4\right)}_n=4[a(x_{n-1}\left(t\right)+{\left(k_3\right)}_{n-1})-b{(x_{n-1}\left(t\right)-\frac{\sqrt{2}}{2}{\left(k_2\right)}_{n-1}+\frac{2+\sqrt{2}}{2}{\left(k_3\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

Wherein x _nfor the n order derivative value of x (t), sn _nbe the n order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1, a, b are the constant of setting, and calculate x ₁(t), x ₂(t) ..., x _n+1(t) value;

To x ₁(t), x ₂(t) ..., x _n+1(t) carry out integration, obtain x (t), and obtain the position x of x (t) in the double-deck stochastic system generation accidental resonance moment of single order and second order differentiate function composition _mvalue and x _mcorresponding resonance moment t1 and with the corresponding noise D1 of t1, D1 is a value in D.

Then pass through formula

$\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\ΔU}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\ΔU}\right)}^2/D_1}$

The signal to noise ratio (S/N ratio) of calculating each spectroscopic data output, obtains SNR ₁, SNR ₂..., SNR _i, wherein Δ U=a ²/ 4b.

Step 4: each check point signal to noise ratio (S/N ratio) output valve freshness threshold value corresponding with it compared and draw each check point signal to noise ratio (S/N ratio) output error value, then each signal to noise ratio (S/N ratio) output error value is carried out to statistic of classification, whether judgement sample is fresh.

Each check point output signal-to-noise ratio is calculated to output signal-to-noise ratio error with the freshness threshold value of corresponding check point, and its formula is ${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\×100\%$ 。The process of statistics meets QE for calculating _ithe number of≤5% output signal-to-noise ratio error, is designated as M ₁, calculate and meet QE _ithe number of the output signal-to-noise ratio error of >5%, is designated as M ₂if, make the judgement that sample is fresh, if make the stale judgement of sample, if all otherwise return to step 2 and sample is detected again and carry out data processing.

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendments or supplement or adopt similar mode to substitute described specific embodiment, but can't depart from spirit of the present invention or surmount the defined scope of appended claims.

Although more used the terms such as pedestal, bracket, radiation source, adjusting mechanism, receiving mechanism herein, do not got rid of the possibility that uses other term.Use these terms to be only used to describe more easily and explain essence of the present invention; They are construed to any additional restriction is all contrary with spirit of the present invention.

Claims (10)

1. an identifying meat freshness system, it is characterized in that: comprise pedestal (1), on pedestal, be provided with the bracket (2) for placing sample, above bracket, be provided with radiation source (3), described radiation source is rotatably connected on the adjusting mechanism (4) of adjusting radiation source position, adjusting mechanism is arranged on pedestal, below bracket, be provided with receiving mechanism (5), control module (12) is set in pedestal, and control module is connected with radiation source, adjusting pole, receiving mechanism;

Radiation source: transmitting detects light beam to sample, and can receive the reflected light information on sample, feeds back to control module;

Receiving mechanism: remain with radiation source and align, receive the transmitted light of radiation source, and feed back to control module;

Control module: control radiation source, adjusting mechanism, receiving mechanism work, according to the spectral information of radiation source or receiving mechanism feedback, calculate sample signal to noise ratio (S/N ratio) by accidental resonance analysis meter, and with drawing sample freshness information after tables of data.

2. a kind of identifying meat freshness system according to claim 1, it is characterized in that being connected with control circuit for light source between described radiation source (3) and control module (12), control circuit for light source comprises keyboard (28), input block (29), function memory (30) and power amplifier unit (31), described keyboard connects input block, input block contiguous function storer, function memory is connected with power amplifier unit, power amplifier unit is connected with radiation source, and power amplifier unit is connected with control module.

3. a kind of identifying meat freshness system according to claim 1, it is characterized in that described receiving mechanism (5) includes receiver (6), slide (7) and swingle (8), described slide is the arcuate structure taking radiation source rotating shaft as the center of circle, on slide, have and be provided with chute (9), described receiver is arranged in chute, on chute two side, be provided with gathering sill (10), on receiver both sides, correspondence is provided with angle sheave (11), gathering sill is provided with the gear teeth, angle sheave is arranged in gathering sill, angle sheave is gear, angle sheave is meshed and is connected with gathering sill, slide is fixed on swingle upper end, swingle rotates and is arranged on pedestal (1).

4. a kind of identifying meat freshness system according to claim 3, it is characterized in that being provided with in described receiver (6) drive motor (13) of output shafts, two output shafts of drive motor are connected with angle sheave (11) respectively, connect the first motor (14) that drives swingle to rotate in described swingle lower end, it is upper that drive motor and the first motor are connected to control module (12), on receiver bottom, is provided with roller (27).

5. a kind of identifying meat freshness system according to claim 1, it is characterized in that described adjusting mechanism (4) comprises first body of rod (18), second body of rod (19), rotary screw (20) and guide pole (21), first body of rod vertically arranges, described radiation source (3) is connected on the lower end of first body of rod by rotating shaft (22), rotating shaft is connected with the second motor that driver rotates, the first body of rod upper end is through on clutch shaft bearing (23), be provided with the 3rd motor (16) on bearing top, the 3rd motor output shaft is connected with the first body of rod upper end, described second body of rod and the perpendicular setting of first body of rod, the second lever front end is fixed on clutch shaft bearing, be disposed with thread bush (24) and orienting sleeve (25) in the second body of rod rear end, described rotary screw and guide pole are arranged side by side on pedestal, thread bush and orienting sleeve are nested with respectively on rotary screw and guide pole, be connected with the 4th motor (17) in rotary screw lower end, rotary screw upper end connects the second bearing (26), guide pole upper end and the second bearing fix, the second motor, the 3rd motor and the 4th motor are connected on control module (12).

6. an identifying meat freshness method, adopts the device in claim 1-5 any one, it is characterized in that: comprise the following steps:

Step 1: detect in advance the volatile base nitrogen value of different resting period meat samples, obtain the some groups of freshness of meat threshold values corresponding with radiation source position;

Step 2: prepare meat sample, sample is placed on bracket, radiation source adopts the position identical with step 1 to be radiated on sample, then radiation source intensity decline and change according to sinusoidal curve according to tangent cutve increase during the course, control module collection reflection or transmittance spectra data, then adjust radiation source irradiation position, reflection or transmittance spectra data at the some variant points of sample collection like this;

Step 3: by each check point spectroscopic data substitution accidental resonance model, by accidental resonance model being carried out to single order and second order differentiate, and single order accidental resonance model is passed through to quadravalence jade for asking rain Ge Kuta algorithm, calculate each check point signal to noise ratio (S/N ratio) output valve;

Step 4: each check point signal to noise ratio (S/N ratio) output valve freshness threshold value corresponding with it compared and draw each check point signal to noise ratio (S/N ratio) output error value, then each signal to noise ratio (S/N ratio) output error value is carried out to statistic of classification, whether judgement sample is fresh.

7. a kind of identifying meat freshness method according to claim 6, the volatile base nitrogen TVB-N value that it is characterized in that detecting in advance in step 1 different resting period meat samples, obtains the freshness of meat threshold value SNR corresponding with the radiation source anglec of rotation with some groups _thre1, SNR _thre2..., SNR _threi, i=1 ... m, m is check point quantity.

8. a kind of identifying meat freshness method according to claim 6, is characterized in that in step 3, the each spectroscopic data gathering being distinguished in substitution accidental resonance model, and its formula is as follows,

Wherein for input matrix, comprise periodically sinusoidal signal spectral measurement signal Spect (t), and in grasp noise N (t), A is signal amplitude, f is signal frequency, and D is external noise intensity, and ξ (t) is external noise, x (t) is Brownian movement Particles Moving lopcus function, and t is run duration;

Accidental resonance model is carried out to single order and second order differentiate is that V (x, t) carries out single order and second order differentiate for x, and to make its equation be 0, obtain formula and be,

Set noise intensity D=0, spect (t)=0, N (t)=0, the critical value that B=1 tries to achieve cyclical signal is

By A _cin substitution first derivation function, establish X ₀(t)=0, sn ₀=0;

With quadravalence jade for asking rain Ge Kuta Algorithm for Solving single order accidental resonance model, obtain:

$x_{n+1}\left(t\right)=x_n\left(t\right)+1/6[{\left(k_1\right)}_n+(2-\sqrt{2}){\left(k_2\right)}_n+(2+\sqrt{2}){\left(k_3\right)}_n+{\left(k_4\right)}_n]$

And calculate

${\left(k_1\right)}_n=4({\mathrm{ax}}_{n-1}\left(t\right)-{\mathrm{bx}}_{n-1}^3\left(t\right)+{\mathrm{sn}}_{n-1})$

${\left(k_2\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{{\left(k_1\right)}_{n-1}}{2})}^3+{\mathrm{sn}}_{n-1}]$

${\left(k_3\right)}_n=4[a(x_{n-1}\left(t\right)+\frac{{\left(k_2\right)}_{n-1}}{2})-b{(x_{n-1}\left(t\right)+\frac{\sqrt{2}-1}{2}{\left(k_1\right)}_{n-1}+\frac{2-\sqrt{2}}{2}{\left(k_2\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

${\left(k_4\right)}_n=4[a(x_{n-1}\left(t\right)+{\left(k_3\right)}_{n-1})-b{(x_{n-1}\left(t\right)-\frac{\sqrt{2}}{2}{\left(k_2\right)}_{n-1}+\frac{2+\sqrt{2}}{2}{\left(k_3\right)}_{n-1})}^3+{\mathrm{sn}}_{n+1}]$

Wherein x _nfor the n order derivative value of x (t), sn _nbe the n order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1, a, b are the constant of setting, and calculate x ₁(t), x ₂(t) ..., x _n+1(t) value;

To x ₁(t), x ₂(t) ..., x _n+1(t) carry out integration, obtain x (t), and obtain the position x of x (t) in the double-deck stochastic system generation accidental resonance moment of single order and second order differentiate function composition _mvalue and x _mcorresponding resonance moment t1 and with the corresponding noise D1 of t1, D1 is a value in D;

Then pass through formula

$\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\ΔU}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\ΔU}\right)}^2/D_1}$

The signal to noise ratio (S/N ratio) of calculating each spectroscopic data output, obtains SNR ₁, SNR ₂..., SNR _i, wherein Δ U=a ²/ 4b.

9. a kind of identifying meat freshness method according to claim 7, is characterized in that in step 4, output signal-to-noise ratio error is that each check point output signal-to-noise ratio is calculated with the freshness threshold value of corresponding check point, and its formula is ${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\×100\%$ , the process of statistics meets QE for calculating _ithe number of≤5% output signal-to-noise ratio error, is designated as M ₁, calculate and meet QE _ithe number of the output signal-to-noise ratio error of >5%, is designated as M ₂if, make the judgement that sample is fresh, if make the stale judgement of sample, if all otherwise return to step 2 and sample is detected again and carry out data processing.

10. according to a kind of identifying meat freshness method described in claim 6 or 7, the testing process that it is characterized in that freshness of meat threshold value is: the total volatile basic nitrogen numerical value that detects a meat every day, until the total volatile basic nitrogen numerical value of certain day sample exceeds standard for the first time, this day sample carried out to the operation of step 2 to step 3, the signal to noise ratio (S/N ratio) output obtaining is freshness threshold value, when detection, started by radiation source position for the first time, detect each time afterwards, radiation source angle increases by 5 degree clockwise.