CN104089902A - Beef freshness detection device and detection method - Google Patents

Abstract

The invention relates to a beef freshness detection device and detection method. The detection device comprises an opaque shell, a halogen lamp, a spectrometer, a light intensity adjustment instrument, and a light-emitting head, a bracket and a light-receiving instrument arranged in the shell. The bracket comprises a bottom plate, a sample support plate over the bottom plate, a light-transmitting plate disposed on the sample support plate and an L-shaped fixation arm disposed on the edge of the bottom plate. The L-shaped fixation arm includes a horizontal plate over the sample support plate and a vertical rod that passes through the sample support plate and is fixedly connected to the sample support plate. The horizontal plate's part over the light-transmitting plate is provided with a vertical extension arm extending toward the light-transmitting plate. The device and the method provided by the invention have the characteristics of fast detection speed, more detection points, and higher reliability and precision of detection data.

Description

A kind of pick-up unit of degree of beef freshness and detection method

Technical field

The present invention relates to measurement techniques for quality detection of meat detection technique field, especially relate to a kind of pick-up unit and detection method that can detect accurately and rapidly the whether corrupt degree of beef freshness of beef.

Background technology

Beef has feature nutritious and that mouthfeel is good, is deeply subject to liking of consumers in general.

But beef is easy to be polluted and goes bad.In storage process, along with propagation and a series of physicochemical change of microorganism, the freshness of beef decreases.The abundant nutritional labelings such as protein, fat and carbohydrates are utilized by bacterium and enzyme, produce the sour gas of ammonia, sulfuration ammonia, aldehydic acid, aldehyde, ketone, ethanethio, alcohol and carboxylic acid.Aldehyde, ketone, ester and other low molecular compound in metabolic product makes beef produce peculiar smell.

At present, conventionally adopt spectrum stimulus light source to irradiate sample (adopting a Halogen lamp LED of often opening or LED lamp to impinge upon on sample) both at home and abroad, and gather incident illumination be mapped to after sample diffuse or through the transmitted light of sample, diffuse reflection spectrum or transmitted spectrum are analyzed, finally realized the detection to sample quality; But this detection method exists the detection quantity of information collecting less, the lower deficiency of precision of detection.

Chinese patent Granted publication number: CN101769889A, July 7 2010 Granted publication day, the electric nasus system that a kind of quality of agricultural product detects is disclosed, comprise that one mainly completes the gas enrichment module that low concentration smell is collected, one is mainly converted into olfactory signal air chamber gas path module and the sensor array of electric signal, one mainly carries out filtering to sensor array output signal, analog to digital conversion, the Conditioning Circuits of Sensor of feature extraction and data preprocessing module, a pair of signal is identified and is judged, and with the embedded system of data storage, one shows and result output module, described gas enrichment module is made up of the adsorption tube, heating wire and the attemperating unit that are filled with adsorbent.This invention has function singleness, the deficiency that detection time is long.

Summary of the invention

The present invention is the deficiency in order to overcome the low and length consuming time of detection method precision of the prior art, and a kind of pick-up unit and detection method that can detect accurately and rapidly the whether corrupt degree of beef freshness of beef is provided.

To achieve these goals, the present invention is by the following technical solutions:

A pick-up unit for degree of beef freshness, described pick-up unit comprises light tight housing, Halogen lamp LED, spectrometer, light intensity regulating device, is located at light emitting head, support and optical pickup apparatus in housing; Described support comprises base plate, is positioned at the sample splint of base plate top, is located at the light-passing board on sample splint and is located at the L shaped fixed arm on bottom edge; Described L shaped fixed arm comprises and is positioned at the leveling board of sample splint top and the guide pole being slidably connected with sample splint, the position that is positioned at light-passing board top of leveling board is provided with the vertical adjutage extending to light-passing board, leveling board is provided with the first drive motor for driving vertical adjutage to horizontally rotate, and described vertical adjutage bottom is provided with the second drive motor for driving light emitting head to swing back and forth at vertical guide;

Leveling board is provided with the screw mandrel for driving sample splint lifting, and screw mandrel bottom is rotationally connected with the stationary pipes of being located on sample splint, and leveling board is provided with the 5th drive motor for driving screw mandrel rotation;

Described optical pickup apparatus comprise be located on base plate with the coaxial support column of vertical adjutage, be located at the guide rail on support column and be located on guide rail for receiving the light-receiving head of incident light through the transmitted light after sample, described guide rail is with swinging center taking light emitting head circular-arc as the center of circle; In described base plate, be provided with the 3rd drive motor for driving support column rotation, light-receiving head is provided with the 4th drive motor for driving light-receiving head to move in guide rail;

Light intensity regulating device, Halogen lamp LED and light emitting head are connected successively, and light-receiving head is electrically connected with spectrometer, on spectrometer and each drive motor, are equipped with the signal output port for being electrically connected with computing machine.

Light intensity regulating device of the present invention is for regulating the light intensity of the light source that Halogen lamp LED sends, computing machine is horizontally rotated, on vertical guide, rotated by first, second and the 5th drive motor control light emitting head and Quality control supporting plate moves up and down, computing machine horizontally rotates by the 3rd Electric Machine Control support column, catches transmitted light by the 4th Electric Machine Control light-receiving head; Thereby the present invention can be detected the multiple points on sample, adopt different incident angle, height of incidence to irradiate, and the detection signal that each point of irradiation is obtained carries out data analysis, and obtain the freshness of beef sample, that detects is wider, detection information more comprehensively, has improved the reliability of testing result.

Light detects the principle of learning degree of beef freshness: light beam is through after sample, because the different chemical characteristic group comprising in different freshness samples is different, therefore be different for the degree of absorption of different wave length incident light, thereby each wavelength light intensity is different in transmitted light, therefore can go to characterize according to these information the freshness of sample.But if the light intensity of incident light is fixed, incident light is stably radiated on sample, each chemical group in sample for the degree of absorption of different wavelengths of light in state of saturation, although can obtain detection information, quantity of information is abundant, and accurately determining of detection is lower.

The present invention adopts the incident light that light intensity constantly changes to irradiate sample, at incident light intensity gradually in the large or change procedure that reduces, different groups are gradually large or reduce to the absorption of respective wavelength light, now the degree of absorption of group is in unsaturation, saturated diminuendo process, in transmitted light, comprise more detection information, thereby make the detection signal obtaining can symbolize more accurately the freshness of beef.

Therefore, it is fast that the present invention has detection speed, and check point is more, and the reliability and the precision that detect data are higher.

As preferably, described light intensity regulating device comprises data collecting card and power amplifier, described data collecting card is provided with the signal input interface for being electrically connected with computing machine, described data collecting card is electrically connected with the input end of power amplifier, and the output terminal of described power amplifier is electrically connected with the power supply of Halogen lamp LED.

Computing machine produces the waveform for controlling intensity variation, data collecting card gathers this waveform signal, and output on power amplifier, the output terminal of power amplifier is electrically connected with the power supply of Halogen lamp LED, thereby realize the adjusting of the light intensity of the light source that Halogen lamp LED is sent by controlling the power supply of Halogen lamp LED, and pass through the incident light of light emitting head to sample irradiation Strength Changes.

As preferably, described guide rail comprises guiding base plate, be located at guiding plate upper surface and along the arc of guiding base plate to two spaced grooves that extend, described groove floor is provided with the tooth bar of uniformly-spaced arranging; Described light-receiving head bottom is provided with two gears that match with groove; Described the 4th drive motor is positioned at light-receiving head bottom, the rotating shaft of the 4th drive motor be located at two coupling shafts between gear and be connected.The structure of guide rail is arranged so that light-receiving head can move back and forth under the drive of the 4th drive motor in guide rail.

As preferably, described guiding base plate also comprises the first curved baffle, and second curved baffle relative with the first curved baffle is positioned at the 3rd baffle plate, the 4th baffle plate at first, second curved baffle two ends; The first arc, the second curved baffle are provided with corresponding guide chute; The coupling shaft two ends of described gear are provided with the outrigger shaft of the guide chute for inserting the first arc, the second curved baffle.

The setting of the guide chute of the first curved baffle and the second curved baffle, while making the motion of light-receiving head, stability is better.

As preferably, described drive motor is stepper motor; Support column is connected with base plate by bearing, and vertical adjutage is connected with leveling board by bearing, and light emitting head is connected with vertical adjutage by bearing.

A detection method for the pick-up unit of degree of beef freshness, comprises the steps:

(6-1) P that is preset with each motor that incoming position, height of incidence and the incident angle on sample is relevant to light emitting head in computing machine organizes anglec of rotation data, the initial rotation angle degree of each motor is 0, and the initial position of light emitting head is vertical state; Set detection position sequence number i=1;

According to CNS GB/T5009.44-2003, detect the total volatile basic nitrogen TVB-N value of different resting period beef samples, and obtain the freshness threshold value SNR corresponding with P group anglec of rotation data difference _thre1, SNR _thre2..., SNR _threp;

(6-2) sample preparation: take out sheet meat as detected sample from beef to be detected;

(6-3) detect: computing machine is electrically connected with spectrometer and each motor, sample is kept flat on light-passing board;

(6-3-1) first, second and the 5th drive motor of computer control drives light emitting head horizontally rotate, swing and drive sample splint to move up and down, light emitting head is radiated on the predetermined corresponding irradiation position of i group anglec of rotation data, and makes the 3rd drive motor drive support column to synchronize and rotate with adjutage;

(6-3-2) after light emitting head reaches predetermined incoming position, incident angle and height of incidence, the moving driven by motor light-receiving head of computer control 4 wheel driven moves on guide rail, and observe by spectrometer the light intensity that light-receiving head receives, computing machine be parked in guide rail by the moving Electric Machine Control light-receiving head of 4 wheel driven with the corresponding position of light intensity maximal value;

(6-3-3) computing machine regulates light emitting head output detections light by light intensity regulating device, and described detection light rises to maximal value MAT from 0 according to straight line, then drops to 0 from maximal value MAT according to sinusoidal curve; Spectrometer receives the detection signal Spect (t) corresponding with detecting light;

(6-3-4) as i < P, make i value increase by 1, repeating step (6-3-1), to (6-3-3), obtains P detection signal Spect (t);

(6-4) computing machine all does following data processing to P detection signal Spect (t):

(6-4-1) by detection signal Spect (t) input one deck accidental resonance model in, wherein, V (x, t) is potential function, x (t) is Brownian movement Particles Moving lopcus function, and a, b is the constant of setting, and ξ (t) is external noise, and D is external noise intensity, and N (t) grasps noise in being, for periodicity sinusoidal signal, A is signal amplitude, and f is signal frequency, and t is run duration, for phase place, establish

(6-4-2) computing machine calculates first order derivative and the second derivative of V (x, t) for x, and makes equation equal 0, obtains two layers of accidental resonance model:

Set noise intensity D=0, spect (t)=0, N (t)=0; The critical value that calculates A is

(6-4-3) by critical value substitution one deck accidental resonance model of A, and set X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck 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 _n(t) be the n order derivative of x (t), sn _n-1that the n-1 order derivative of S (t) is at the value at t=0 place, sn _n+1be the n+1 order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1; Obtain x ₁(t), x ₂(t) ..., x _n+1(t) value;

(6-4-4) computing machine is 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 one deck accidental resonance model and two layers of accidental resonance model composition _mvalue and x _mcorresponding resonance moment t ₁and and t ₁corresponding noise D ₁, D ₁for a value in D;

(6-4-5) computing machine utilizes formula $\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\&Delta;U}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\&Delta;U}\right)}^2/D_1}$ Calculate the signal to noise ratio (S/N ratio) of double-deck stochastic resonance system output; Wherein, Δ U=a ²/ 4b; Obtain P output signal-to-noise ratio SNR ₁, SNR ₂..., SNR _p;

(6-5) computing machine utilizes formula ${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\&times;100\%$ Calculate the corresponding output signal-to-noise ratio error of i group anglec of rotation data QE _i, wherein, i=1 ..., P;

Computing machine calculates and meets QE _ithe number M of≤5% output signal-to-noise ratio error ₁; Computing machine calculates and meets QE _ithe number M of the output signal-to-noise ratio error of > 5% ₂;

If (6-6) computing machine is made the judgement that sample is fresh;

If computing machine is made the stale judgement of sample;

Otherwise it is 1 that computing machine makes i value, return to step (6-3-1), sample is again detected and carries out data processing.

As preferably, the thickness of described sheet meat is 35 to 150mm.

As preferably, incident angle is 0 to 46 degree.

As preferably, the span of MAT is 110 luxs, lux to 210.

Therefore, the present invention has following beneficial effect: (1) detection speed is fast; (2) check point is more, and the reliability and the precision that detect data are higher.

Brief description of the drawings

Fig. 1 is a kind of structural representation of the present invention;

Fig. 2 is a kind of theory diagram of the present invention;

Fig. 3 is a kind of cut-open view of guide rail of the present invention;

Fig. 4 is a kind of vertical view of guide rail of the present invention;

Fig. 5 is that detection light intensity of the present invention changes schematic diagram;

Fig. 6 is a kind of process flow diagram of embodiments of the invention.

In figure: Halogen lamp LED 1, spectrometer 2, light intensity regulating device 3, support 4, optical pickup apparatus 5, base plate 6, sample splint 7, sample is placed net 8, L shaped fixed arm 9, leveling board 10, guide pole 11, vertical adjutage 12, the first drive motor 13, the second drive motor 14, support column 15, guide rail 16, light-receiving head 17, the 3rd drive motor 18, the 4th drive motor 19, data collecting card 20, power amplifier 21, computing machine 22, light emitting head 23, guiding base plate 161, groove 162, gear 163, coupling shaft 164, the first curved baffle 165, the second curved baffle 166, guide chute 167, outrigger shaft 168, the 3rd baffle plate 169, the 4th baffle plate 170, the 5th drive motor 24, stationary pipes 25, screw mandrel 26.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention will be further described.

Embodiment is as shown in Figure 1 and Figure 2 a kind of pick-up unit of degree of beef freshness, and pick-up unit comprises light tight housing, Halogen lamp LED 1, and spectrometer 2, light intensity regulating device 3, is located at light emitting head 23, support 4 and optical pickup apparatus 5 in housing; Support comprises base plate 6, is positioned at the sample splint 7 of base plate top, is located at the light-passing board 8 on sample splint and is located at the L shaped fixed arm 9 on bottom edge; L shaped fixed arm comprises and is positioned at the leveling board 10 of sample splint top and the guide pole 11 being slidably connected with sample splint, the position that is positioned at light-passing board top of leveling board is provided with the vertical adjutage 12 extending to light-passing board, leveling board is provided with the first drive motor 13 for driving vertical adjutage to horizontally rotate, and vertical adjutage bottom is provided with the second drive motor 14 for driving light emitting head to swing back and forth at vertical guide;

Leveling board is provided with the screw mandrel 26 for driving sample splint lifting, and screw mandrel bottom is rotationally connected with the stationary pipes 25 of being located on sample splint, and leveling board is provided with the 5th drive motor 24 for driving screw mandrel rotation;

Stationary pipes is for being with female vertical duct, and stationary pipes is fixedly connected with sample splint, thereby drives sample splint to move up and down in the time that screw mandrel rotates.

As shown in Figure 1, Figure 3, optical pickup apparatus comprise be located on base plate with the coaxial support column 15 of vertical adjutage, be located at the guide rail 16 on support column and be located on guide rail for receiving the light-receiving head 17 of incident light through the transmitted light after sample, guide rail is with swinging center taking light emitting head circular-arc as the center of circle; In base plate, be provided with the 3rd drive motor 18 for driving support column rotation, light-receiving head is provided with the 4th drive motor 19 for driving light-receiving head to move in guide rail;

As shown in Figure 2, light intensity regulating device comprises N1-6259 data collecting card 20 and power amplifier 21, data collecting card is provided with the signal input interface for being electrically connected with computing machine, data collecting card is electrically connected with the input end of power amplifier, and the output terminal of power amplifier is electrically connected with the power supply of Halogen lamp LED.

As shown in Fig. 1, Fig. 3, Fig. 4, guide rail comprises the base plate 161 that leads, is located at the arc of guiding plate upper surface edge guiding base plate to two spaced grooves 162 of extension, and groove floor is provided with the tooth bar of uniformly-spaced arranging; Light-receiving head bottom is provided with two gears that match with groove 163; The 4th drive motor is positioned at light-receiving head bottom, the rotating shaft of the 4th drive motor be located at two coupling shafts 164 between gear and be connected, be also provided with the 3rd baffle plate 169 and the 4th baffle plate 170.

Guiding base plate also comprises the first curved baffle 165 and second curved baffle 166 relative with the first curved baffle; The first arc, the second curved baffle are provided with corresponding guide chute 167; The coupling shaft two ends of gear are provided with the outrigger shaft 168 of the guide chute for inserting the first arc, the second curved baffle.

Drive motor is stepper motor; Support column is connected with base plate by bearing, and vertical adjutage is connected with leveling board by bearing, and light emitting head is connected with vertical adjutage by bearing; Light-passing board is the quartz glass plate of 0.4mm to 1mm.In the present embodiment, adopt the quartz glass plate of 0.4mm as light-passing board.

As shown in Figure 6, a kind of detection method of pick-up unit of degree of beef freshness, comprises the steps:

8 groups of anglec of rotation data that are preset with each motor that incoming position, height of incidence and the incident angle on sample is relevant to light emitting head in computing machine, the initial rotation angle degree of each motor is 0, and the initial position of light emitting head is vertical state; Set detection position sequence number i=1;

According to CNS GB/T5009.44-2003, detect the total volatile basic nitrogen TVB-N value of different resting period beef samples, and obtain the freshness threshold value SNR corresponding with P group anglec of rotation data difference _thre1=-75.45dB, SNR _thre2=-68.57dB, SNR _thre3=-62.37dB, SNR _thre4=-55.32dB, SNR _thre5=-48.41dB, SNR _thre6=-41.93dB, SNR _thre7=-34.51dB, SNR _thre8=-30.65dB;

Freshness threshold value SNR _thre1, SNR _thre2..., SNR _threpthe method obtaining is as follows:

Detect the total volatile basic nitrogen numerical value of the fresh beef of just having slaughtered, after having detected, beef is put in cold storage plant and is stored, second day, the 3rd day, ... take out beef and continue to detect the total volatile basic nitrogen numerical value of beef, detected at every turn and all put into cold storage plant and store, when the total volatile basic nitrogen numerical value of certain day sample exceeds standard for the first time, the sample of this day is adopted following step 100 to detect to 300,8 SNR that obtain are freshness threshold value SNR _thre1, SNR _thre2..., SNR _thre8.

Freshness threshold value is relevant to storage condition, to detect obtained freshness threshold value SNR at the beef sample of certain temperature, pressure and humidity storage _thre1, SNR _thre2..., SNR _thre8, can only be for detection of the freshness of the beef of storing under the same conditions.

Step 100, sample preparation: take out the sheet meat of 80mm as detected sample from beef to be detected;

Step 200, detects: computing machine is electrically connected with spectrometer and each motor, sample is kept flat on light-passing board;

Step 210, computer control first, second drive light emitting head horizontally rotate, swing and drive sample splint to move up and down with the 5th drive motor, light emitting head is radiated on the predetermined corresponding irradiation position of i group anglec of rotation data, and makes the 3rd drive motor drive support column to synchronize and rotate with adjutage;

Step 220, after light emitting head reaches predetermined incoming position and incident angle, the moving driven by motor light-receiving head of computer control 4 wheel driven moves on guide rail, and observe by spectrometer the light intensity that light-receiving head receives, computing machine be parked in guide rail by the moving Electric Machine Control light-receiving head of 4 wheel driven with the corresponding position of light intensity maximal value;

Step 230, computing machine regulates light emitting head output detections light by light intensity regulating device, as shown in Figure 5, within 10 second time, detect light and rise to maximal value 200 luxs from 0 according to straight line, then within 10 second time, dropped to 0 from maximal value 200 luxs according to sinusoidal curve; Spectrometer receives the detection signal Spect (t) corresponding with detecting light;

Step 240, as i < 8, makes i value increase by 1, and repeating step 210 to 230, obtains P detection signal Spect (t);

Step 300, computing machine all does following data processing to 8 detection signal Spect (t):

Step 310, by detection signal Spect (t) input one deck accidental resonance model in, wherein, V (x, t) is potential function, x (t) is Brownian movement Particles Moving lopcus function, a, and b is the constant of setting, ξ (t) is external noise, D is the external noise intensity with 0.01 stepping in [0,1] scope, and N (t) grasps noise in being for periodicity sinusoidal signal, A is signal amplitude, and f is signal frequency, and t is run duration, for phase place, establish

Step 320, computing machine calculates first order derivative and the second derivative of V (x, t) for x, and makes equation equal 0, obtains two layers of accidental resonance model:

Set noise intensity D=0, spect (t)=0, N (t)=0; The critical value that calculates A is

Step 330, (6-4-3) by critical value substitution one deck accidental resonance model of A, and sets X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck 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 _n(t) be the n order derivative of x (t), sn _nbe the n order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1; Obtain x ₁(t), x ₂(t) ..., x _n+1(t) value;

Step 340, computing machine is 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 one deck accidental resonance model and two layers of accidental resonance model composition _mvalue and x _mcorresponding resonance moment t ₁, and and t ₁corresponding noise D ₁, D ₁for a value in D; D is a function with 0.01 loop cycle stepping in [0,1] scope, and the value of D and time correlation, known t ₁moment, D ₁just determine.

Step 350, computing machine utilizes formula $\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\&Delta;U}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\&Delta;U}\right)}^2/D_1}$ Calculate the signal to noise ratio (S/N ratio) of double-deck stochastic resonance system output; Wherein, Δ U=a ²/ 4b; Obtain 8 output signal-to-noise ratio SNR ₁, SNR ₂..., SNR ₈;

Step 400, the error of calculation:

Computing machine utilizes formula ${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\&times;100\%$ Calculate the corresponding output signal-to-noise ratio error of i group anglec of rotation data QE _i, wherein, i=1 ..., 8;

Computing machine calculates and meets QE _ithe number M of≤5% output signal-to-noise ratio error ₁; Computing machine calculates and meets QE _ithe number M of the output signal-to-noise ratio error of > 5% ₂;

Step 500, judges:

If computing machine is made the judgement that sample is fresh;

If computing machine is made the stale judgement of sample;

Otherwise it is 1 that computing machine makes i value, returns to step 210, sample is again detected and carries out data processing.

M in the present embodiment ₁=7, therefore, computing machine is made the judgement that sample is fresh.

Should be understood that the present embodiment is only not used in and limits the scope of the invention for the present invention is described.In addition should be understood that those skilled in the art can make various changes or modifications the present invention after having read the content of the present invention's instruction, these equivalent form of values fall within the application's appended claims limited range equally.

Claims (9)

1. the pick-up unit of a degree of beef freshness, it is characterized in that, described pick-up unit comprises light tight housing, Halogen lamp LED (1), spectrometer (2), light intensity regulating device (3), is located at light emitting head (23), support (4) and optical pickup apparatus (5) in housing; Described support comprises base plate (6), is positioned at the sample splint (7) of base plate top, is located at the light-passing board (8) on sample splint and is located at the L shaped fixed arm (9) on bottom edge; Described L shaped fixed arm comprises and is positioned at the leveling board (10) of sample splint top and the guide pole (11) being slidably connected with sample splint, the position that is positioned at light-passing board top of leveling board is provided with the vertical adjutage (12) extending to light-passing board, leveling board is provided with the first drive motor (13) for driving vertical adjutage to horizontally rotate, and described vertical adjutage bottom is provided with the second drive motor (14) for driving light emitting head to swing back and forth at vertical guide;

Leveling board is provided with the screw mandrel (26) for driving sample splint lifting, screw mandrel bottom is rotationally connected with the stationary pipes (25) of being located on sample splint, and leveling board is provided with the 5th drive motor (24) for driving screw mandrel rotation;

Described optical pickup apparatus comprises the support column coaxial with vertical adjutage (15) be located on base plate, be located at the guide rail (16) on support column and be located on guide rail for receiving the light-receiving head (17) of incident light through the transmitted light after sample, described guide rail is with swinging center taking light emitting head circular-arc as the center of circle; In described base plate, be provided with the 3rd drive motor (18) for driving support column rotation, light-receiving head is provided with the 4th drive motor (19) for driving light-receiving head to move in guide rail;

Light intensity regulating device, Halogen lamp LED and light emitting head are connected successively, and light-receiving head is electrically connected with spectrometer, on spectrometer and each drive motor, are equipped with the signal output port for being electrically connected with computing machine (22).

2. the pick-up unit of a kind of degree of beef freshness according to claim 1, it is characterized in that, described light intensity regulating device comprises data collecting card (20) and power amplifier (21), described data collecting card is provided with the signal input interface for being electrically connected with computing machine, described data collecting card is electrically connected with the input end of power amplifier, and the output terminal of described power amplifier is electrically connected with the power supply of Halogen lamp LED.

3. the pick-up unit of a kind of degree of beef freshness according to claim 1, it is characterized in that, described guide rail comprises the base plate (161) that leads, is located at the arc of guiding plate upper surface edge guiding base plate to two spaced grooves (162) of extension, and described groove floor is provided with the tooth bar of uniformly-spaced arranging; Described light-receiving head bottom is provided with two gears that match with groove (163); Described the 4th drive motor is positioned at light-receiving head bottom, the rotating shaft of the 4th drive motor be located at two coupling shafts (164) between gear and be connected.

4. the pick-up unit of a kind of degree of beef freshness according to claim 3, it is characterized in that, described guiding base plate also comprises the first curved baffle (165), second curved baffle (166) relative with the first curved baffle, is positioned at the 3rd baffle plate (169), the 4th baffle plate (170) at first, second curved baffle two ends; The first arc, the second curved baffle are provided with corresponding guide chute (167); The coupling shaft two ends of described gear are provided with the outrigger shaft (168) of the guide chute for inserting the first arc, the second curved baffle.

5. according to the pick-up unit of a kind of degree of beef freshness described in claim 1 or 2 or 3 or 4, it is characterized in that, described drive motor is stepper motor; Support column is connected with base plate by bearing, and vertical adjutage is connected with leveling board by bearing, and light emitting head is connected with vertical adjutage by bearing.

6. a detection method that is applicable to the pick-up unit of degree of beef freshness claimed in claim 1, is characterized in that, comprises the steps:

(6-1) P that is preset with each motor that incoming position, height of incidence and the incident angle on sample is relevant to light emitting head in computing machine organizes anglec of rotation data, the initial rotation angle degree of each motor is 0, and the initial position of light emitting head is vertical state; Set detection position sequence number i=1;

According to CNS GB/T5009.44-2003, detect the total volatile basic nitrogen TVB-N value of different resting period beef samples, and obtain the freshness threshold value SNR corresponding with P group anglec of rotation data difference _thre1, SNR _thre2..., SNR _threp;

(6-2) sample preparation: take out sheet meat as detected sample from beef to be detected;

(6-3) detect: computing machine is electrically connected with spectrometer and each motor, sample is kept flat on light-passing board;

(6-3-1) first, second and the 5th drive motor of computer control drives light emitting head horizontally rotate, swing and drive sample splint to move up and down, light emitting head is radiated on the predetermined corresponding irradiation position of i group anglec of rotation data, and makes the 3rd drive motor drive support column to synchronize and rotate with adjutage;

(6-3-2) after light emitting head reaches predetermined incoming position, incident angle and height of incidence, the moving driven by motor light-receiving head of computer control 4 wheel driven moves on guide rail, and observe by spectrometer the light intensity that light-receiving head receives, computing machine be parked in guide rail by the moving Electric Machine Control light-receiving head of 4 wheel driven with the corresponding position of light intensity maximal value;

(6-3-3) computing machine regulates light emitting head output detections light by light intensity regulating device, and described detection light rises to maximal value MAT from 0 according to straight line, then drops to 0 from maximal value MAT according to sinusoidal curve; Spectrometer receives the detection signal Spect (t) corresponding with detecting light;

(6-3-4) as i < P, make i value increase by 1, repeating step (6-3-1), to (6-3-3), obtains P detection signal Spect (t);

(6-4) computing machine all does following data processing to P detection signal Spect (t):

(6-4-1) by detection signal Spect (t) input one deck accidental resonance model in, wherein, V (x, t) is potential function, x (t) is Brownian movement Particles Moving lopcus function, and a, b is the constant of setting, and ξ (t) is external noise, and D is external noise intensity, and N (t) grasps noise in being, for periodicity sinusoidal signal, A is signal amplitude, and f is signal frequency, and t is run duration, for phase place, establish

(6-4-2) computing machine calculates first order derivative and the second derivative of V (x, t) for x, and makes equation equal 0, obtains two layers of accidental resonance model:

Set noise intensity D=0, spect (t)=0, N (t)=0; The critical value that calculates A is

(6-4-3) by critical value substitution one deck accidental resonance model of A, and set X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck 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 _n(t) be the n order derivative of x (t), sn _n-1that the n-1 order derivative of S (t) is at the value at t=0 place, sn _n+1be the n+1 order derivative of S (t) in the value at t=0 place, n=0,1 ..., N-1; Obtain x ₁(t), x ₂(t) ..., x _n+1(t) value;

(6-4-4) computing machine is 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 one deck accidental resonance model and two layers of accidental resonance model composition _mvalue and x _mcorresponding resonance moment t ₁and and t ₁corresponding noise D ₁, D ₁for a value in D;

(6-4-5) computing machine utilizes formula $\mathrm{SNR}=\sqrt{2}{\left(\mathrm{\&Delta;U}\frac{{4a}^3/27b}{D_1}\right)}^2{e}^{-{\left(\mathrm{\&Delta;U}\right)}^2/D_1}$ Calculate the signal to noise ratio (S/N ratio) of double-deck stochastic resonance system output; Wherein, Δ U=a ²/ 4b; Obtain P output signal-to-noise ratio SNR ₁, SNR ₂..., SNR _p;

(6-5) computing machine utilizes formula ${\mathrm{QE}}_i=\left|\frac{{\mathrm{SNR}}_i-{\mathrm{SNR}}_{\mathrm{threi}}}{{\mathrm{SNR}}_{\mathrm{threi}}}\right|\&times;100\%$ Calculate the corresponding output signal-to-noise ratio error of i group anglec of rotation data QE _i, wherein, i=1 ..., P;

Computing machine calculates and meets QE _ithe number M of≤5% output signal-to-noise ratio error ₁; Computing machine calculates and meets QE _ithe number M of the output signal-to-noise ratio error of > 5% ₂;

If (6-6) computing machine is made the judgement that sample is fresh;

If computing machine is made the stale judgement of sample;

Otherwise it is 1 that computing machine makes i value, return to step (6-3-1), sample is again detected and carries out data processing.

7. the detection method of the pick-up unit of degree of beef freshness according to claim 6, is characterized in that, the thickness of described sheet meat is 30 to 150mm.

8. the detection method of the pick-up unit of degree of beef freshness according to claim 6, is characterized in that, incident angle is 0 to 46 degree.

9. according to the detection method of the pick-up unit of the degree of beef freshness described in claim 6 or 7 or 8, it is characterized in that, the span of MAT is 110 luxs, lux to 210.