CN101556244B - Measurement method for chlorophyll content in cucumber leaves based on RGB chlorophyll meter - Google Patents

Abstract

The invention belongs to the technical field of photoelectric measurement, relating to a chlorophyll measurement method based on RGB digital signals. The method comprises the following steps of: (1) according to a multiplex linear regression equation of chlorophyll content measurement in cucumber leaves, configuring parameters to a RGB chlorophyll meter and obtaining an embedded model of measuring the chlorophyll content by the chlorophyll meter: -34.54+13.79log10Rt-93.58log10Bt+56.51log10Gt=y, wherein Rt is transmitted red light intensity frequency, Gt is transmitted green light intensity frequency, Bt is transmitted blue light intensity frequency, and y is chlorophyll content in cucumber leaves; (2) measuring cucumber leaves to be measured by the RGB chlorophyll meter so as to obtain chlorophyll content and frequency signals of red light, green light and blue light; and (3) calculating chlorophyll content by the RGB chlorophyll meter according to the embedded model. The method has the characteristics of simple and stable lighting source, relatively accurate measured chlorophyll content and the like.

Description

Cucumber leaves chlorophyll content measuring method based on RGB chlorophyll instrument

Technical field

The invention belongs to the photoelectric measurement technical field, relate to a kind of measuring method of cucumber leaves chlorophyll content.

Background technology

Chlorophyll is that green plants carries out photosynthetic material base, is the important indicator of the growth of research plant, physiological metabolism and nutrition condition.The chlorophyll content of measuring plant leaf blade can be for the research physiological feature, recommend nitrogen application, tap the production potential and variety source etc. provides scientific basis.The plant leaf blade measuring chlorophyll content mainly contains three kinds of chemical analysis, computer vision method and chlorophyll instrument methods.This quantivative approach precision of chemical analysis is higher, need grind blade but produce chlorophyll solution, wastes time and energy, and has destroyed leaf tissue, is only applicable to laboratory measurement.The computer vision method can be applicable to vehicle-mounted farmland diagnostic system, is a kind of quick, non-contacting measuring method, but its realization needs the participation and the mass data storehouse deposit of host computer, and the total system volume is bigger, carries inconvenience.Chlorophyll instrument method is to see through light or catoptrical relevant information by what read plant leaf blade, draws a kind of method of plant leaf chlorophyll content.Chlorophyll instrument method has in real time, fast, does not destroy advantages such as blade.The most representative in the existing portable chlorophyll instrument is the SPAD502 of Japanese Minolta company.SPAD502 inside has sends the LED that wavelength is the light of 650nm and 940nm (LightEmitting Diode, light emitting diode), and chlorophyll has higher absorbance to the infrared light of 650nm, and extremely low to the infrared light absorbance of 940nm.The principle of work of SPAD502 is to be reference with the 940nm infrared light, measures the absorbance of blade at the 650nm place.Because SPAD502 only utilizes the photo measure of two wave bands, the absorbance information that obtains is limited, so measuring accuracy is lower.

Summary of the invention

Purpose of the present invention is exactly at the deficiencies in the prior art, and a kind of method that is applicable to that the cucumber leaves chlorophyll content is measured is provided, and it is simple, stable that it has a lighting source, and chlorophyll content is measured relatively accurate characteristics.

The present invention adopts following technical scheme:

A kind of cucumber leaves chlorophyll content measuring method based on RGB chlorophyll instrument, adopt following RGB chlorophyll measuring apparatus: its physical construction partly comprises light source, objective table, sensor holder, be placed with white light LEDs in the light source, the sensor holder bottom is placed with color sensor, and light source, objective table and sensor holder constitute lucifuge formula sonde configuration; Its circuit part comprises the light source module that drives white light LEDs, the digital signal sensors module, and the digital signal processing control module, light source module drives white light LEDs, makes it send stable test white light; The digital signal sensors module is utilized the color sensor acquisition time to see through ruddiness in the detection light of determinand, green glow, blue light intensity signal and light intensity signal is converted into square-wave signal, is sent to the digital signal processing control module; The digital signal processing control module is caught by three kinds of square-wave signals and processing obtains the correspondent frequency signal, and measures embedded model according to the chlorophyll that parameter configuration obtains, and calculates chlorophyll content, comprises the following steps:

4) multiple linear regression equations of measuring according to following cucumber chlorophyll content is carried out parameter configuration to RGB chlorophyll instrument, obtains the embedded model that RGB chlorophyll instrument is measured chlorophyll content:

-34.54+13.79log ₁₀(R _t)-93.58log ₁₀(B _t)+56.51log ₁₀(G _t)=y is in the formula: R _tIt is transmit red light intensity frequency; G _tIt is transmit green intensity frequency; B _tIt is transmit blue intensity frequency; Y is the cucumber leaves chlorophyll content;

5) utilize RGB chlorophyll instrument to measure cucumber leaves to be measured, obtain the frequency signal of chlorophyll content and ruddiness, green glow, blue light intensity signal;

6) utilize RGB chlorophyll instrument according to embedded model, calculate chlorophyll content.

The present invention is a light source with stable white light, utilize the color sensor acquisition time to see through ruddiness, green glow, the blue light intensity signal for the treatment of measuring plants, light source is simple, stable, and compares with chlorophyll instrument SPAD502, the information of obtaining is horn of plenty more, can reach higher degree of accuracy; The present invention constitutes a lucifuge formula sonde configuration together with light source, objective table, sensor holder, and this structure is for the chlorophyll content in leaf blades measurement provides the lucifuge environment, guarantees that the light near normal that light source sends beats on objective table and sensor.In a word, cucumber leaves chlorophyll measuring method of the present invention, it is simple, stable to have a lighting source, and chlorophyll content is measured advantages such as relatively accurate.

Description of drawings

Fig. 1 is the system architecture synoptic diagram;

Fig. 2 is the circuit diagram of light source module;

Fig. 3 is the TCS230 functional block diagram;

Fig. 4 is the digital signal sensors module circuit diagram;

Fig. 5 is a digital signal processing control module circuit diagram;

Fig. 6 is a main program flow chart;

Fig. 7 is the LCD MODULE circuit diagram;

Fig. 8 is a USB flash disk data memory module circuit diagram;

Fig. 9 is the voltage transformation module circuit diagram;

Figure 10 is the lithium cell charging module circuit diagram;

Figure 11 is the instrument mechanical construction drawing;

Figure 12 is objective table impeller structure figure;

Figure 13 is an objective table bacterium structural drawing.

Specific implementation method

The invention will be further described below in conjunction with drawings and Examples.

(1) functional module of instrument and circuit thereof

The chlorophyll measuring apparatus of this example, structure comprise the led light source module as shown in Figure 1, digital signal sensors module, digital signal processing control module, USB flash disk data memory module, LCD LCD MODULE, and the physical construction part of instrument.Testing light source is all band White LED, and light source module is used for LED and drives, and makes LED send stable test white light; The test white light is vertically beaten on plant leaf blade and is seen through plant leaf blade and received by digital signal sensors module main chip TCS230, TCS230 contains inside three kinds of optical filters corresponding to ruddiness (R), green glow (G), blue light (B), filter plate timesharing gating, the transmitted light light intensity signal is converted into square-wave signal, and square wave frequency is directly proportional with the transmitted light light intensity.Square-wave signal is input to the digital signal processing control module, this module main chip single-chip microcomputer utilizes inner integrated comparison/seizure/width modulation (CCP) module to carry out the seizure of square-wave signal, and adopt to survey periodic method and obtain R, G, the tripartite wave frequency of B, handle square wave frequency and calculate the chlorophyll content of institute's measuring plants blade according to its embedded mathematical model.

Below the selection of some functional modules is further described:

(1) light source module: adopting the high brightness full-spectrum LED is the instrument test radiant.LED test light light intensity changes with the variation of forward current, has guaranteed the stability of test light light intensity, and light-source system adopts special LED chip for driving---MAX1910 charge pump type LED chip for driving.This chip is transformed into the LED operating voltage with input voltage.Internal charge pump guarantees that SET end terminal voltage is 200mV, and the electric current of LED remains unchanged thereby assurance is flowed through, and has kept the brightness of LED.The MAX1910 volume is little, and peripheral circuit is simple, is that the ideal that is applied to portable instrument is selected.

Light source module has corresponding circuit, and as shown in Figure 2, its circuit is MAX1910 integrated circuit (IC) chip U5 by model, capacitor C 6-C10, and resistance R 9-R10, plug connector JP4, JP5 constitute; Capacitor C 6, C7 common end grounding, the other end links to each other by resistance R 9, the non-earth terminal of C7 directly links to each other with MAX1910 pin 2, pin 6, pin 8, the non-earth terminal of C6 links to each other with supply voltage VCC, 9 pin of 4 pin, the one termination U5 of one termination U5 of capacitor C 8,7 pin of 3 pin, the one termination U5 of capacitor C 9 one termination U5, the white light LEDs both positive and negative polarity links to each other with pin 2 with JP5 pin 1 respectively, JP5 pin 1 links to each other with capacitor C 10 1 ends and also receives 5 pin of U5, C10 other end ground connection, JP5 pin 2 receives 10 pin of U5 and by R10 ground connection, JP4 pin 2 links to each other with ground with voltage VCC respectively with pin 1.

(2) digital signal sensors module: receive to comprise the transmitted light of plant leaf blade chlorophyll content information and be converted into square-wave signal and export.Digital RGB color sensor is the TCS230 that U.S. TAOS company produces.It is industry first have the RBG color sensor of digital compatibility interface.TCS230 integrates photodiode array and electric current-frequency converter, light intensity signal is converted into the frequency signal of the square wave of dutycycle 50%.It has the output of 10 bit digital, and the resolving power height is that core sensor can be made spectrophotometric substitute products with it.TCS230 adopts the SOIC surface-adhered type encapsulation of 8 pins, and volume is little, and its peripheral circuit is simple, is applicable to portable equipment.The typical frequencies output area of TCS230 color sensor: 2Hz～500KHz, the gating of passage and output-scale-factor is configurable, can adapt to different measurement ranges.Select required wave filter by pin S2, S3, select 100%, 20%, 2% output-scale-factor or power remove pattern by pin S0, S1.The TCS230 structured flowchart as shown in Figure 3, Color Channel, output-scale-factor are selected as shown in table 1.

Table 1 Color Channel, output-scale-factor are selected

S0	S1	Output-scale-factor	S2	S3	Color
						L	L	Power remove	L	L	Red
L	H
			2％	L	H	Blue
H	L
			20％	H	L	Do not have
H	H							100％	H	H	Green

The digital signal sensors module has corresponding circuit, and as shown in Figure 4, it is the integrated circuit U4 of TCS230D by model, capacitor C 29, and single-pole double-throw switch (SPDT) S4-S5, resistance R 28 is formed; 6,7,8 pin of integrated circuit U4 are connected respectively to 17,2,3 pin that the single-chip microcomputer model is PIC18F4523,5 pin of U4 meet supply voltage VCC simultaneously, 3,4 pin ground connection, 1, the public pole of 2 pin order double-pole double throw switch S4 and S5, the other two ends of single-pole double-throw switch (SPDT) one end ground connection, the other end meets the anodal VCC of supply voltage by resistance R 28, and U4 pin 3, pin 4 link to each other and be connected to U4 pin 5 by C29.

(3) digital signal processing control module: finish collection and the processing and the control of system's medium frequency signal by single-chip microcomputer.Single-chip microcomputer model: the PIC18F4523 of MICROCHIP company.Advantages such as the PIC series monolithic adopts reduced instruction set computer, Harvard's bus structure, and gets finger with pipeline system, and it is strong to have an antijamming capability, and travelling speed is fast.The command byte of PIC18F4523 single-chip microcomputer is 16, belongs to the high-grade single-chip microcomputer of PIC series, can be implemented in line debugging and online programming.

Frequency collection is finished by the CCP module of PIC single-chip microcomputer.CCP (Capture/Compare/PWM) module is made as trap mode, going up of input square wave jumped along as interrupt event, set up array T[n].Jump on each along the place, single-chip microcomputer all produces interruption, and CCP1 catches this value of TMR1H:TMR1L constantly, and deposits it in T[n] in, cycle of square wave can be obtained thus.Single Chip Microcomputer (SCM) program adopts the C language compilation, under the MPLAB environment, carries out on-line debugging with ICD2.Main program flow chart as shown in Figure 5, S0, S1, S2, S3 are respectively reset key, initiating key, display key and reset key among the figure.

The digital signal processing control module has corresponding circuit, and as shown in Figure 6, it is the integrated circuit U1 chip of PIC18F4523 by model, capacitor C 11-C14, and crystal oscillator Y1, resistance R 12-R27, little button 1-4, plug connector JP10 forms; Capacitor C 11 and C12 parallel connection and terminate to 11 pin of U1 and meet the anodal VCC of supply voltage, the other end is received 12 pin and the ground connection of U1, U1 pin 13 connects 2 ends of crystal oscillator Y1 and passes through capacitor C 13, C14 connects 1 end of crystal oscillator and links to each other with 14 pin of U1, the 19-22 of U1, the 27-30 pin connects the supply voltage positive pole by pull-up resistor R20-R27, and be connected to the D0-D7 of LCD MODULE web member JP12 and the 15-22 pin of USB flash disk memory module U6 (CH375), keypad 2,3,42 end ground connection, 1 end is by resistance R 15, R17, R19 meets the anodal VCC of supply voltage, 34 of U1,35,6 pin are by resistance R 14, R16, R18 receives keypad 2,3,41 end, 2 end ground connection of keypad 1,1 end is by resistance R 12, R13 connects positive source, 1 termination R12 and the R13 connecting place of U1, and be connected to 1 pin of JP10, the 2 termination VCC of JP10,3 end ground connection, 4,5 termination U1 pin 40,39,6 ends are unsettled.

(4) LCD MODULE: this module is used for test data and shows, employing has that low-power consumption, volume are little, the LCD (LCD) of light weight, LCM128643 for Qingyun Chuangxin Science ﹠ Tech Co Ltd, Beijing, it adopts 8 bit parallel data transfer modes, include the DC-DC circuit, operating voltage is 5V, and the exemplary operation electric current is 2.7mA, adopt the COB encapsulation, show by Micro Controller Unit (MCU) driving LCD.The I/O mouth APORTD mouth of single-chip microcomputer PIC18F4523 directly is connected with the 8 bit data mouths of LCD, carries out exchanges data and instruction transmission.Simultaneously, single-chip microcomputer utilizes pin RB1, RB4, RB5, RC1, RC0 to link to each other with RS, RW, E, CSB, the CSA pin of LCD, the character and the direction of control data exchange.The inner integrated required negative voltage source of LCM128643 is in the circuit of reality, with V _oBe connected on the adjustable end of potentiometer, potentiometer two stiff ends are connected on V _OutOn the pin of GND, can be by regulating V _oVoltage change the brightness of LCD

LCD MODULE has corresponding circuit, and as shown in Figure 7, the plug connector JP12 of LCD MODULE circuit wherein links to each other with LCD LCM128643C, and the JP12 peripheral circuit is by resistance R 29-R32, single-pole double-throw switch (SPDT) S6, and capacitor C 19 is formed; 20 pin of 3 pin of slide rheostat R32 one termination JP12 and another termination of ground connection JP12, output terminal connects JP12 pin 5 in the middle of it, single-pole double-throw switch (SPDT) S6 common port connects for VCC and ground by R30, R31 respectively, S6 is the optional termination JP12 pin 17 in two ends in addition, JP12 pin 19 meets VCC by R29, by electrochemical capacitor C19 ground connection, and JP12 pin 18 ground connection, pin 4 meets VCC, and JP12 pin 1,2,6,7,8 connects U1 pin 15,16,34,37,38.

(5) the USB flash disk data memory module is used for the immediate access measurement data, this modular circuit as shown in figure 10, circuit is by integrated circuit (IC) chip U6, plug connector JP11, resistance R 26, R33, R34, capacitor C 22-C28, crystal oscillator Y2 forms; Integrated circuit U6 is the usb bus interface chip, model is CH375, U6 pin 28 meets VCC, VCC is by C26 ground connection, and U6 pin 2 meets VCC by C22, and U6 pin 9 is by C23 ground connection, U6 pin 13 is by C24 ground connection, pin 14 is by C25 ground connection, crystal oscillator Y2 one termination U6 pin 13, another termination U6 pin 14, U6 pin 24 is by resistance R 33 sending and receiving optical diode D2 negative poles, the D2 positive pole meets supply voltage VCC, U6 pin 5,12,23 equal ground connection, U6 pin 1,3,4,8,27 respectively with U1 pin 33,9,8,6,10 link to each other, JP11 pin 1 is by C28 ground connection and pass through R34, C27 ground connection, R34, the public termination supply voltage of C27 VCC, JP11 pin 2, pin 3 connects U6 pin 10, pin 11, JP11 pin 4 ground connection.This circuit input end connects single-chip microcomputer and can realize inserting at any time the function that computing machine carries out data read.

(6) voltage transformation module also has corresponding circuit, and as shown in Figure 9, wherein circuit is by integrated circuit M1 chip, resistance R 6-R8, and capacitor C 3-C5, diode D3-D5, plug connector JP2, JP3, single-pole double-throw switch (SPDT) S1, S2 form; Integrated circuit M1 is the voltage transitions chip, model is MAX667, single-pole double-throw switch (SPDT) S1 common port and diode D3, the D4 negative pole links to each other, and pass through D3, D4 respectively with anode (JP1 pin 2), DC voltage VCCS links to each other, S1 two ends in addition has an end by shunt capacitance C3, C4 ground connection also is connected to M1 pin 8, resistance R 6 one termination M1 pin 8, another termination M1 pin 3 also passes through R7 ground connection, resistance R 8 one termination M1 pin, 2 another termination M1 pin 7 also link to each other with D5 is anodal, and C5 one another termination of end ground connection M1 pin 2 also links to each other plug connector JP2 with the S2 public pole, the corresponding pin of JP3 pin links to each other, pin 1 connects one of S2 residue two ends, pin 2 ground connection, M1 pin 4,5,6 ground connection, the D5 minus earth.

(7) the lithium cell charging module is used for providing power supply to this instrument, is convenient to the open air and carries.This module has corresponding circuit, and as shown in Figure 8, lithium cell charging modular circuit wherein is BQ2057W by integrated circuit (IC) chip U2 model, resistance R 1-R5, and capacitor C 0-C2, triode Q1, diode D1, plug connector JP0, JP1 form; Integrated circuit U2 is the battery charge chip, triode Q1 model is FZT788B, pass through shunt capacitance C0 between DC voltage VCCS and the ground GND, C1 connects, C0, C1 DC voltage VCCS end links to each other with U2 pin 3, U2 pin 1 links to each other with dc voltage VCCS by resistance R 1, U2 pin 2 links to each other with anode, resistance R 2 one ends link to each other with DC voltage VCCS, and the other end connects U2 pin 4 and by R1 ground connection, diode D1 positive pole links to each other with U2 pin 5, negative pole is by resistance R 5 ground connection, U2 pin 6 ground connection, U2 pin 8 connect DC voltage VCCS end, and triode Q1 pin 3 connects U2 pin 1, pin 1 connects U2 pin 7 by resistance R 4, pin 2 and pin 4 are by capacitor C 2 ground connection and connect anode, and anode connects 2 ends of JP1, and negative pole connects 1 end of JP1, DC voltage VCCS connects 2 ends of JP0, and ground connects 1 end of JP0.

(2) the mechanical composition structure of instrument

Below the physical construction of this instrument is further described:

As shown in figure 11, instrument physical construction partly comprises casing 1, rotating shaft 2, and connecting rod 3, column 4, light source 5, objective table 6, sensor holder 7, plug 8 is equipped with white light LEDs in the light source 5.The bottom of sensor holder 7 wherein is fixed with color sensor TCS230.Light source 5, objective table 6, sensor holder 7 constitute a lucifuge formula sonde configuration together, this structure provides the lucifuge environment for the chlorophyll content in leaf blades measurement, this structure guarantees that the light near normal that light source sends beats on objective table and sensor, and light source 5 can lift the measurement that realizes the picking and placeing of blade, fixing and big blade.Objective table wherein has two kinds of structures: a kind of is objective table leaf 6.1, is used for the plant leaf blade nondestructive measurement, and this structure is a T stage formula structure, and upper and lower surface all is the plane, and there is one 4 * 4cm the centre ²Square hole, the structure of objective table leaf is as shown in Figure 1; Another kind of objective table is an objective table bacterium 6.2, be used for the measurement of various mushrooms, this structure is to dig two grooves that vary in size on objective table leaf upper surface basis, the vat 6.2.1 degree of depth is 2mm, the sulculus 6.2.2 degree of depth is 5mm, and it is that the screw thread of 1mm is used for fixing the wave carrier piece that is loaded with mushroom, dark externally threaded hollow cylinder 6.2.3 of 1mm and little groove fit that 5mm depth recess inside surface has internal diameter.The structure of objective table bacterium as shown in figure 13.Casing 1 is used for the installation of electronic circuit board in this physical construction, and connecting rod is by on the connecting rod, form under the connecting rod; Plug 8 is big by plug, the plug combo becomes.Rotating shaft 2, connecting rod 3, column 4, plug 8 are connected casing 1 with probe segment, their inside all has dead slot and realizes that circuit is connected between casing and probe segment electronic circuit board.

(3) based on the cucumber leaves chlorophyll content measuring method of this chlorophyll instrument

Before cucumber leaves to be measured is measured, at first according to the multiple linear regression equations that obtains:

-34.54+13.79log ₁₀(R _t)-93.58log ₁₀(B _t)+56.51log ₁₀(G _t)=y is in the formula: R _tIt is transmit red light intensity frequency; G _tIt is transmit green intensity frequency; B _tIt is transmit blue intensity frequency; Y is that the cucumber leaves chlorophyll content utilizes keyboard that chlorophyll measuring apparatus is carried out parameter configuration, the embedded regression equation when obtaining RGB chlorophyll instrument measurement cucumber leaves.

During measurement, the LED white light source is shone cucumber leaves measurement zone to be measured, the transmitted light that passes blade is received by color sensor module and exports three square-wave signals of corresponding transmitted light redness (R), green (G), blue (B) intensity signal by this module, and square wave frequency is directly proportional with light intensity.The digital signal processing control module is caught three kinds of square-wave signals and is handled the frequency that obtains square-wave signal, again according to frequency signal and embedded multiple linear regression equations, calculate chlorophyll content, last digital signal processing control module is sent to LCD liquid crystal display and USB flash disk data storage with square-wave signal frequency, chlorophyll content.

To utilize RGB chlorophyll instrument to compare below to the test of cucumber leaves and data processing and with SPAD502.

When obtaining the cucumber leaves chlorophyll content, cucumber leaves be to damage, therefore, when comparing RGB chlorophyll instrument and SPAD502 measurement effect, should before measuring the cucumber leaves chlorophyll content, rgb value, SPAD value be measured with spectrophotometer method.

Metering system: get two groups of cucumber leaves samples, first group of cucumber leaves is 21, and second group is 19.Every leaf is a sample, and each sample standard deviation is measured with RGB chlorophyll instrument, SPAD502, spectrophotometer, obtains rgb value, SPAD value, the chlorophyll content of every leaf respectively.Utilize card punch on every leaf, to get 8 small pieces subsamples (2 small pieces are got in top, middle and upper part, middle and lower part, bottom), be used for the measurement of rgb value, SPAD value, every subsample rgb value, SPAD value are the average of every subsample multimetering, every leaf rgb value, SPAD value are the mean value of 8 subsample rgb values, SPAD value, represent with Rt, Gt, Bt, SPAD respectively, carry out the mensuration of every leaf chlorophyll content again with spectrophotometer, represent with y.

Utilize Matlab that first group of cucumber leaves handled, obtain RGB chlorophyll apparatus measuring value and chlorophyll content relational expression

-34.54+13.79log ₁₀(R _t)-93.58log ₁₀(B _t)+56.51log ₁₀(G _t)＝y (1)

R wherein ²=0.57, R=0.755, n=21.R is a linearly dependent coefficient.According to the look-up table in the equation of linear regression test of significance approach equation of linear regression is significantly checked.Look-up table is the form that critical R value that the statist calculates according to significance of correlation coefficient t method of inspection is listed, and sees Table 2.Look-up table is that to look into degree of confidence according to degree of freedom n-2 be 0.05 and 0.01 o'clock critical R value, R _{0.05 (n-2)}, R _{0.01 (n-2)}, during check, with what calculate | R| and R _{0.05 (n-2)}, R _{0.01 (n-2)}Relatively, make statistical inference.Table look-up in this test R _{0.01 (n-2)}=0.665, R _{0.05 (n-2)}=0.575, by 0.755＞0.665, regression equation is for extremely remarkable, and the cucumber leaves chlorophyll content is measured regression model and set up.With second group of cucumber leaves RGB chlorophyll apparatus measuring value and chlorophyll content substitution formula (1), to cucumber leaves measure equation (1) checking, R at this moment ²=0.5619, R=0.75, n=22.Table look-up (2): R _{0.01 (n-2)}=0.652, R _{0.05 (n-2)}=0.563,0.75＞0.652, still for extremely remarkable, checking cucumber leaves measure equation (1) is set up.

Utilize Matlab to obtain relational expression between first group of cucumber leaves SPAD value and the chlorophyll content:

1.93SPAD+0.06＝y (2)

R ²＝0.7746，R＝0.88，n＝21。With second group of cucumber leaves measured value SPAD and chlorophyll content value substitution formula (2), R2=0.3668, R=0.6056, n=22.Linearly dependent coefficient when relatively second group of cucumber leaves measured, 0.727＞0.702, RGB chlorophyll instrument repeatability when measuring the cucumber leaves chlorophyll content is good than SPAD502.Show that RGB chlorophyll instrument can be used for the measurement of chlorophyll content in leaf blades, measurement effect can compare favourably with SPAD502.

The conspicuousness numerical value of table 2r and R

Claims (1)

1. cucumber leaves chlorophyll content measuring method based on RGB chlorophyll instrument, adopt following RGB chlorophyll measuring apparatus: its physical construction partly comprises light source, objective table, sensor holder, be placed with white light LEDs in the light source, the sensor holder bottom is placed with color sensor, and light source, objective table and sensor holder constitute lucifuge formula sonde configuration; Its circuit part comprises the light source module that drives white light LEDs, the digital signal sensors module, and the digital signal processing control module, light source module drives white light LEDs, makes it send stable test white light; The digital signal sensors module is utilized the color sensor acquisition time to see through ruddiness in the detection light of determinand, green glow, blue light intensity signal and light intensity signal is converted into square-wave signal, is sent to the digital signal processing control module; The digital signal processing control module obtains chlorophyll according to parameter configuration and measures embedded model, three kinds of square-wave signals is caught and processing obtains the correspondent frequency signal, and in conjunction with embedded model, calculate chlorophyll content, comprises the following steps:

1) multiple linear regression equations of measuring according to following cucumber leaves chlorophyll content is carried out parameter configuration to RGB chlorophyll instrument, obtains the embedded model that RGB chlorophyll instrument is measured chlorophyll content:

-34.54+13.79log ₁₀(R _t)-93.58log ₁₀(B _t)+56.51log ₁₀(G _t)=y is in the formula: R _tIt is transmit red light intensity frequency; G _tIt is transmit green intensity frequency; B _tIt is transmit blue intensity frequency; Y is the cucumber leaves chlorophyll content;

2) utilize RGB chlorophyll instrument to measure cucumber leaves to be measured, obtain the frequency signal of ruddiness, green glow, blue light intensity signal;

3) utilize RGB chlorophyll instrument according to embedded model, calculate chlorophyll content.

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