CN1746660A - Method and measuring instrument for measuring crop canopy pigment ratio - Google Patents

Abstract

A method for measuring pigment ratio of crop canopy includes detecting incoming light of sunlight and reflecting light of vegetation separately by utilizing sunlight as light source and by setting six photoelectric transducers with the same spectrum response character at three wavelength places of near infrared, `red light and blue light; using micro controller to solve out SIPI value according to SIPI value calculation formula after detected signal is A / D converted, and obtaining result characterizing state of crop growth based on SIPI calculation and displaying result on liquid crystal screen.

Description

Method and measuring instrument for measuring crop canopy pigment ratio

technical field

The invention belongs to the field of plant physiological instruments, in particular to a method for measuring the ratio of crop canopy pigments by using crop canopy reflection spectrum and an instrument designed based on the method, which can quickly and conveniently measure the ratio of crop canopy pigments, and accurately Evaluating the growth status of crops, and then implementing variable fertilization and irrigation according to the water and fertilizer requirements of crops in different growth periods, plays an important role in guiding crop cultivation.

Background technique

Predecessors have done a lot of research on remote sensing crop nutrient content monitoring. Blackmer et al. (1996) believed that the reflection spectrum and projection spectrum of single leaves are affected by nitrogen deficiency; Daughtry (2000) proposed that the reflection spectrum of crop canopies can be used to monitor Evaluation of canopy chlorophyll content, etc. Previous studies mainly carried out statistical analysis between the canopy spectrum and the nitrogen content measured in the same target laboratory, and screened sensitive bands and band combinations for remote sensing monitoring of canopy biochemical components. After analyzing a large number of experimental data, this study concluded that the structure-insensitive vegetation index (SIPI) can be used to invert the pigment ratio content of the crop canopy. For the pigment ratio, we choose the ratio of carotenoids and chlorophyll. Canopy Structure Insensitive Vegetation Index (SIPI) was developed in 1995 by and so on. Define SIPI as:

SIPI＝(R800-R445)/(R800-R680) (1)

Among them, R ₈₀₀ , R ₆₈₀ , and R ₄₄₅ are the spectral reflectance values at wavelengths of 800nm, 680nm, and 445nm, respectively. A large number of studies have shown that the near-infrared band 800nm can be used to reduce the influence of the structure of the blade surface and the internal part of the blade. The bands 445nm and 680nm are the absorption peaks of carotenoids and chlorophyll a, respectively. In this paper, the canopy structure-insensitive vegetation index (SIPI) was used to retrieve the ratio of canopy carotenoids and chlorophyll a. When crops are subjected to changes in physiological and biochemical substances and growth conditions caused by environmental stress, the relative contents of carotenoids and chlorophyll a in the crops will change, so the relative contents of carotenoids and chlorophyll a in the crops can reflect The growing state of the crop.

It can be seen from Figure 1 that there is a very significant linear correlation level between the canopy structure insensitive vegetation index at the flowering stage and the ratio of canopy carotenoids and chlorophyll a under different fertilizer and water conditions of different varieties. The coefficient of determination of the equation is 0.7207, and the number of samples for 64. The experimental research results on the relationship between carotenoids and chlorophyll a are consistent with the research results of Merzlyak (1999). It is believed that the decay rate of chlorophyll is faster than that of carotenoids in crops under stress and senescence. Figure 1 shows that the canopy structure-insensitive vegetation index (SIPI) can be used to retrieve the ratio of canopy carotenoids and chlorophyll a of crops.

At present, ground object spectrometers are often used to measure SIPI. The equipment required for this measurement method is complex in structure, heavy in weight, expensive in value, difficult to operate, and requires secondary processing of measurement data, so it is difficult to popularize and apply.

Contents of the invention

The purpose of this invention is to provide a new method for measuring the crop canopy pigment ratio of crop canopy, the crop canopy pigment ratio tester designed according to this method is light in weight, small in size, low in cost, simple in structure and easy to use , Suitable for mass production and application.

A new method for measuring the ratio of crop canopy pigments, using sunlight as a passive light source, respectively detecting the incident light of the sun and the reflected light of the measured vegetation at three characteristic wavelengths. The radiation signal intensity of the three characteristic bands of , red light and near-infrared, the six radiation analog signals are converted by A/D, and processed by the microcontroller according to the calculation formula of canopy structure insensitive vegetation index (SIPI), The SIPI value is obtained, and the final calculation result is displayed on a liquid crystal display. In addition, measurement results can be stored and uploaded. The key point of this method is to use interference filters to perform light filtering to generate the three characteristic wavelengths required in the present invention.

The crop canopy pigment ratio measuring instrument designed according to the above method includes six photodetectors 38,39,40,47,48,49 as in accompanying drawing 4, optical lens 53,54,55, A/D converter 42 , single-chip microcomputer 43, display 44, six narrow-band interference filters 35, 36, 37, 50, 51, 52; six narrow-band interference filters are divided into three groups, and each group is two filters with the same optical characteristics , and their central wavelengths are located in the near-infrared (0.795-0.805μm) and red (0.665-0.675μm) and blue (0.44-0.45μm) bands respectively; the three photodetectors that measure the incident light signal from the sun are respectively coupled to the near-infrared Optical filter 37, red light filter 36 and blue light filter 35, before optical filter 35,36,37, be provided with diffuser 32,33,34, to reduce the influence of sunlight incidence angle; Measure vegetation reflection Before the three photodetectors of the light signal, imaging objectives 53, 54, 55 are arranged, and the vegetation target at a distance of about 1.3m is imaged by the imaging objectives on the photosensitive surface of the light detector. Infrared filter 52 , red filter 51 and blue filter 50 . The detector and the optical part are connected into an airtight whole through the lens barrel.

The storage circuit on the instrument can store the measured data on the instrument, and the user can upload the data to the host computer through the RS232 serial port for further analysis and processing.

Extended LCD display on the single-chip microcomputer on the instrument, EEPROM memory that does not lose data after power failure, serial A/D converter, signal conditioning circuit, etc.

The operation panel of the instrument is separated from the main body of the instrument, and the operation panel is fixed on the handle of the instrument, which is close to the operator and is convenient to use. In addition, the connector between the handle and the instrument body has 3 rotational degrees of freedom.

The working principle of the instrument is as follows: using sunlight (sunlight) as a light source, through 6 photoelectric sensors, at three specific wavelengths of near-infrared and visible light, respectively detect the incident light of sunlight and the reflected light of the canopy of the vegetation to be measured. The six measured parameters are processed by a single-chip microcomputer to obtain the SIPI value after analog-to-digital conversion, and the obtained result is displayed by a liquid crystal display (LCD). In this application, if the instrument measures the incident light signal at the characteristic wavelength of 445nm as E ₄₄₅ , the corresponding wavelength of the vegetation reflected light signal is E _R445 ; the incident light signal at the 680nm characteristic wavelength is E ₆₈₀ , and the corresponding wavelength of the vegetation reflected light signal is E _R680 ; the incident light signal at the characteristic wavelength of 800nm is E ₈₀₀ , and the reflected light signal of vegetation at the corresponding wavelength is E _R800 , then:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 800</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}}<span\; class="notranslate">\; ;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 680</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 680</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 680</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 680</span>}}}<span\; class="notranslate">\; ;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 445</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}}$

In the formula, k ₈₀₀ , k ₆₈₀ and k ₄₄₅ are proportional constants (instrument parameters), which are determined by the optical system of the instrument (incident part and reflection part), photoelectric sensor and its adaptive amplifier and the characteristic parameters of its circuit. If k ₆₈₀ ＝k ₁ k ₈₀₀ , k ₄₄₅ ＝k ₂ k ₈₀₀ have

$\mathrm{<span\; class="notranslate">\; SIPI</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 800</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 445</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}}}{{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 800</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; 680</span>}}\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 680</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 680</span>}}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 800</span>}}{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="k"\; filenames="A20041007431100121.png"\; state="\{\{state\}\}">k</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 445</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 445</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 800</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="k"\; filenames="A20041007431100111.png"\; state="\{\{state\}\}">k</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 445</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 800</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Formula (2) shows that as long as the undetermined characteristic constants k ₁ and k ₂ of the instrument are determined, the SIPI value can be obtained from the signals measured by the six photoelectric sensors, and then the crop canopy pigment ratio can be obtained.

The function of the above-mentioned photoelectric sensor with special spectral response characteristic is to measure the energy of light of a specific wavelength. It can be seen from the calculation formula of SIPI that the key point of measuring SIPI is to obtain the energy of three specific wavelengths, and the measurement of the energy of three characteristic wavelengths is realized by photoelectric sensors. The photoelectric sensor is composed of narrow-band interference filter, silicon photoelectric sensor and its adaptation amplifier. Narrowband interference filter is a precision optical filter device based on the principle of optical thin film interference, which only allows light in the passband near the central wavelength to pass through, which produces three characteristic wavelengths. The six narrow-band interference filters are divided into three groups, and each group is two filters with the same characteristics. Their central wavelengths are respectively located in the near-infrared (0.795-0.805μm) and red (0.665-0.675μm) bands and blue ( 0.44-0.45μm), the bandwidth of the interference filter should ensure that there is no significant change in the spectral reflectance within the passband, so as to ensure the measurement accuracy of SIPI. Six silicon photoelectric sensors and six narrow-band interference filters form three groups of photoelectric sensors, which are respectively used for the detection of incident light and reflected light of vegetation at three characteristic wavelengths of near infrared, red light and blue light. It has high spectral sensitivity at the characteristic wavelength of visible light, and the size of its photosensitive surface should ensure sufficient signal output and linearity under different daylight lighting conditions. Three incident photoelectric sensors are installed above the instrument to measure the intensity of incident sunlight; three reflective photoelectric sensors are installed below the instrument, facing the measured vegetation, for measuring the intensity of plant reflected light.

The function of the above-mentioned optical system is to ensure the height and area of measurement. The optical system includes the frosted glass in front of the incident daylight signal sensor, the aperture and the receiving objective lens in front of the vegetation reflected light sensor. The focal length of the receiving objective determines the measurement height used. The optical system and the photoelectric sensor are fixed as a whole through the mirror.

The determination of the undetermined characteristic constants k ₁ and k ₂ of the above instrument can be obtained by calibrating the reference plate with equal spectral reflectance at the three characteristic wavelengths of near-infrared, red light and blue light. The size of the reference plate should match the detection range of the instrument match. In addition, it can also be calibrated by obtaining the reflectance with a surface object spectrometer.

The function of the A/D converter, memory, display, single-chip microcomputer and other parts of the above-mentioned instrument is to convert the analog signal output by the silicon photoelectric sensor adaptation amplifier circuit into a digital signal through the analog-to-digital converter, and then the single-chip computer according to the formula (3) Calculate and obtain the SIPI value from the liquid crystal display (LCD), and finally, obtain the growth status according to the linear correlation between the SIPI value and the fertilizer and water conditions for display. Measurement data can be stored in the memory of the instrument, and the data can be uploaded to the PC through the level conversion circuit.

Description of drawings

For a further understanding of the features and advantages of the present invention, reference should be made to the following description and accompanying drawings.

Fig. 1 is the relationship between the canopy structure insensitive vegetation index and the ratio of canopy carotenoids and chlorophyll a at the flowering stage and the different fertilizer and water conditions of different varieties;

Fig. 2 is the appearance structure diagram of the crop canopy pigment ratio measuring instrument;

Fig. 3 is the principle block diagram of crop canopy pigment ratio measuring instrument;

Fig. 4 is a schematic diagram of the internal structure of the crop canopy pigment ratio measuring instrument;

Fig. 5 is a circuit diagram of the crop canopy pigment ratio measuring instrument.

Fig. 6 is a layout diagram of the circuit board components of the crop canopy pigment ratio measuring instrument.

Detailed ways

The crop canopy pigment ratio measuring instrument is placed vertically downward at 1.3 meters away from the vegetation canopy, and its corresponding ground field of view range is 1m × 1m. 45watts/(m ² ), the spectral radiation intensity of sunlight received by sensor 39 in the (0.665-0.675μm) band is 90watts/(m ² ), and the spectral radiation intensity of sunlight received by sensor 40 in the (0.795-0.805μm) band The intensity is 80watts/(m ² ), the spectral reflection intensity of the vegetation canopy received by the sensor 47 in the (0.44-0.45μm) band is 2.25watts/(m ² ), the vegetation canopy received by the sensor 48 is in the (0.665-0.675μm ) band spectral reflection intensity is 45watts/(m ² ), and the spectral reflection intensity of the vegetation canopy received by sensor 49 in the (0.665-0.675μm) band is 20watts/(m ² ), then this can be calculated by formula (2) When the spectral reflectance of the vegetation canopy is 5% in the blue light band, 50% in the red light band, and 25% in the infrared light band, the SIPI of the vegetation canopy is calculated by formula (1) The value is -0.8. Then, according to the relationship between the SIPI value and the ratio of the pigment, the parameters representing the growth state of the crop are obtained. This parameter can be displayed, stored and uploaded.

When using it, the body should avoid blocking the sunlight, and it is recommended that the measurer wear dark clothes to reduce the influence of the reflected light of the clothes on the reflected light of the canopy.

Below we detail the implementation of the instrument:

Figure 1 shows the relationship between the canopy structure-insensitive vegetation index and the ratio of canopy carotenoids and chlorophyll a at the flowering stage, and the different fertilizer and water conditions of different varieties. This relationship is a summary of a large number of spectral test data, and the final displayed results are obtained from this relationship.

Figure 2 is the appearance structure diagram of the portable crop canopy pigment ratio measuring instrument. In the figure 1 is a 445nm incident light sensor, 2 is a 670nm incident light sensor, and 3 is an 800nm incident light sensor. These three sensors are vertically upward and measure sunlight at three The incident light intensity at a characteristic wavelength. 4 in the figure is the power switch of the instrument, and the instrument is powered by batteries. 5 in the figure is the RS232 serial port, which can be connected with the serial port of the computer through the serial port cable to complete the upload of the measurement data. In the figure, 6 is a 445nm reflected light sensor, 7 is a 670nm reflected light sensor, and 8 is an 800nm reflected light sensor. These three sensors are vertically downward to measure the reflected light energy of the canopy of the selected vegetation at the characteristic wavelength. 9 in the figure is the connector between the instrument and the handle 11, which has three degrees of freedom of rotation and is used to adjust the angle and height of the instrument and the handle. 10 among the figure is an operation panel, and the operation panel is fixed on the handle 11, which is convenient for the operation of the operator. The operation panel 10 has a liquid crystal display 13 and operation buttons 12, the liquid crystal display displays the measurement results, and the buttons are used to perform various operations on the instrument. 14 among the figure is the vegetation to be measured, and the measurement area specified in the present invention is 1m×1m, and the measurement height is 1.3m.

Fig. 3 is the functional block diagram of the portable crop canopy pigment ratio measuring instrument, among the figure 15 is the sensor for measuring the incident light signal at the infrared light characteristic wavelength place, 16 is the sensor for measuring the vegetation reflected light signal at the infrared light characteristic wavelength place Sensor, 17 is a sensor for measuring the incident light signal at the characteristic wavelength of red light, 18 is a sensor for measuring the reflected light signal of vegetation at the characteristic wavelength of red light, and 19 is the sensor for measuring the incident light at the characteristic wavelength of red light signal sensor, 20 is a sensor for measuring the vegetation reflected light signal at the characteristic wavelength of red light, 21-26 is an adaptation circuit for photoelectric sensors, and 27 is an A/D (analog-digital) conversion with a multi-channel analog switch Device, 28 are single-chip computers, 29 are numerical value liquid crystal displays for displaying and marking crop growth status, 30 are memory storages for data storage, and 31 are serial port level conversion chips that are adopted for data uploading.

Fig. 4 is a schematic diagram of the internal structure of the portable crop canopy pigment ratio measuring instrument. When in use, it is vertically downward as shown in the figure, and 32, 33 and 34 are diffusers of sand glass to reduce the influence of the incident angle of sunlight on the signal amplitude. 35, 36 and 37 below this diffuser are narrow-band interference filters for the corresponding wavelength ranges (0.795-0.805μm), (0.665-0.675μm) and (0.44-0.45μm) to filter out other wavelengths The incident light of the sun only allows the light at the characteristic wavelength to pass through, and 38, 39 and 40 are three identical photoelectric sensors to measure the blue light (0.44-0.45μm) and red light (0.665- 0.675 μm) and near-infrared light (0.795-0.805 μm) at the characteristic wavelength of sunlight, 53, 54 and 55 are three identical receiving objective lenses, and the field of view (FOV) is designed so that the detection range required by the instrument ( Such as 1m * 1m), at a certain distance (such as 1.3m) from the vegetation at the instrument, it is imaged on the photosensitive surfaces of the silicon photoelectric sensors 47, 48 and 49 at the focal plane of the objective lens, and 50, 51 and 52 are the same as 35, 36 and 37 The interference narrow-band filter is located in the middle of the receiving objective lens 53, 54, 55 and the photoelectric sensor 47, 48, 49, to produce the corresponding blue light (0.44-0.45 μm) and red light (0.665-μm) of the filter 50, 51, 52 0.675 μm) and near-infrared light (0.795-0.805 μm) at the vegetation reflection light at the characteristic wavelength place, photoelectric sensors 47, 48 and 49 respectively receive vegetation in blue light (0.44-0.45 μm), red light (0.665-0.675 μm) and Reflected light in the near-infrared light (0.795-0.805 μm) spectral range, 41 is a 9-volt common dry battery, which provides energy for the crop canopy pigment ratio diagnostic instrument, and 42 is an A/D converter with a multi-channel analog switch , it converts the analog signals of the six photoelectric sensors into digital signals and outputs them to the single-chip microcomputer 43, and the single-chip microcomputer 43 receives the blue light (0.44-0.45 μm), red light (0.665-0.675 μm) and near-infrared light obtained by the six photoelectric sensors (0.795-0.805 μ m) solar illumination intensity and vegetation reflection light intensity in characteristic wavelength range, calculate SIPI value according to formula (3), 44 is display screen, it shows the SIPI value that single-chip microcomputer outputs, and measurement data can be stored in data memory 45 , when needed, the measurement data can be transmitted to the upper computer PC through the serial port 46.

Figure 5 is the circuit diagram of the crop canopy pigment ratio measuring instrument, 56 is the serial port level conversion circuit, and the core chip is Maxim's MAX232. 57 is the core circuit of the single-chip microcomputer, including reset circuit, watchdog monitoring circuit, clock circuit, etc. 58 is an analog-to-digital conversion circuit, which adopts AD with 12-bit serial precision from Texas Instruments. The interface is simple and the precision meets the requirements. 59 is a photoelectric sensor and an adaptation circuit, and the amplifying circuit is connected into a circuit amplifying form. 60 is a memory circuit, which has adopted an EEPROM with an IIC bus, and the data will not be lost when the power is turned off. 61 is the liquid crystal interface circuit, has adopted 4 segment liquid crystals among the present invention, and the data interface is a serial format. 62 is a power supply circuit, adopt 7805 to convert the 9v direct current of battery into 5v supply system and use among the present invention. 63 is a button interface circuit.

Fig. 6 is a layout diagram of the circuit board components of the crop canopy pigment ratio measuring instrument. Among the figure, 64 is an operation button; 65 is an operational amplifier; 66 is a clamping diode; 67 is a sliding resistor; 68 is a memory; 69 is a microcontroller; 70 is a liquid crystal display interface; 71 is a level shifter; Watchdog chip; 73 is an A/D converter; 74 is a crystal oscillator; 75 is a serial port.

Claims (5)

1. method of measuring crop crown layer pigment ratio, it is characterized in that: adopt daylight as passive light source, respectively the reflected light of sun incident light and tested vegetation is surveyed at three characteristic wavelength places, record sun incident light and vegetation reflected light at blue light, the radiation signal intensity of ruddiness and three characteristic wave bands of near infrared, these six radiomimesis signals are changed through A/D, and handle by the computing formula of the insensitive vegetation index of canopy structure (SIPI) by microcontroller, obtain the SIPI value, final calculation result is passed through liquid crystal display displays, in addition, can store and upload measurement result; The key point of this method is to adopt interference filter to filter to produce three required characteristic wavelengths among the present invention.

2. crop crown layer pigment ratio measuring instrument that designs according to claim 1, it is characterized in that: it comprises six photodetectors (38), (39), (40), (47), (48), (49), optical lens (53), (54), (55), A/D converter (42), single-chip microcomputer (43), display (44), six spike interference filters (35), (36), (37), (50), (51), (52); Six spike interference filters are divided into three groups, and every group is two identical optical filters of optical characteristics, and their centre wavelength lays respectively near infrared (0.795-0.805 μ m) and ruddiness (0.665-0.675 μ m) and blue light (0.44-0.45 μ m) wave band; Near infrared filter (37), ruddiness optical filter (36) and blue filter (35) are coupled respectively before three photodetectors of measurement sun incident optical signal, optical filter (35), (36), (37) preceding diffuser (32), (33), (34) of being provided with are to reduce the influence of daylight incident angle; Be provided with image-forming objective lens (53), (54), (55) before three photodetectors of measurement vegetation reflected light signal, image-forming objective lens will be provided with near infrared filter (52), ruddiness optical filter (51) and blue filter (50) in the middle of image-forming objective lens and photodetector apart from the vegetation target imaging about 1.3m on the photosurface of the detector of light.Detector and opticator connect into an airtight integral body by lens barrel.

3. crop crown layer pigment ratio measuring instrument according to claim 2, it is characterized in that: the memory circuit on the instrument can be with the data storage measured on instrument, and the user can upload the data to by the RS232 serial ports and further analyze on the host computer PC and handle.

4. crop crown layer pigment ratio measuring instrument according to claim 2 is characterized in that: data are not lost after expansion LCD demonstration, the power down on the single-chip microcomputer eeprom memory, serial a/d converter, signal conditioning circuit.

5. crop crown layer pigment ratio measuring instrument according to claim 2 is characterized in that: guidance panel separates with apparatus subject, and guidance panel is fixed on the instrument handle, near the operator.In addition, handle has 3 rotary freedoms with the connector of apparatus subject.

Images