Plant canopy image analyzer

1. Application

The plant canopy image analyzer extracts canopy gap rates at multiple angles based on various image processing methods, uses a camera equipped with a fisheye lens to take canopy photos from under the canopy, and uses gap rate parameters to invert various canopy parameters, providing a reliable scientific basis for reasonable fertilization in the field and efficient management of modern farms. It is widely used in scientific research and production guidance in agriculture, forestry, plants, etc.

2. Test principles and methods

The plant canopy image analyzer adopts the principle that canopy porosity is related to canopy structure. It is based on Beer’s law that light is weakened when passing through a medium. Under the conditions of defining a series of assumptions for the plant canopy, a semi-theoretical and semi-empirical formula is used to calculate the canopy structure parameters through the determination of canopy porosity. This is the principle that various canopy meters in the world currently use unanimously. Under the above principle, the plant canopy image analyzer uses a method of measuring canopy porosity by analyzing the image of the sky dome hemisphere under the canopy. This method is the most accurate and labor-saving, time-saving, quick and convenient method among all kinds of methods.

3. Structural composition

The plant canopy image analyzer consists of a fisheye image capture probe (consisting of a fisheye lens and a CMOS image sensor), a measuring rod (rocker arm) with 25 built-in PAR sensors, a laptop computer, and image analysis software. The fisheye probe is installed on the top of a very light rocker arm, which can obtain fisheye images with a 180° viewing angle. The image display and storage are completed by the configured laptop computer.

Technical indicators

1. Measurable indicators:

Leaf area index

Average leaf inclination

Clustering index 1

Clustering index 2

Canopy openness

Sky scattered light transmittance

Direct radiation transmittance of plant canopy at different solar altitudes (clearance rate + transmittance)

Extinction coefficient of canopy at different solar altitudes

Azimuth distribution of leaf area density (opacity)

Photosynthetically active radiation (PAR)

2. Lens angle: 180°

3. Resolution: 2592 × 1944

4. Measurement range: Zenith angle from 0° to 90° (180° fisheye lens) can be divided into ten areas, and azimuth angle 360° can also be divided into ten areas

5. PAR sensing range: Sensing spectrum 400nm to 700nm

6. Measuring range 0 to 3000μmol/㎡•S

7. Analysis software: Plant canopy analysis system

8. Weight: 500g

9. Working and storage environment: -10℃~55℃ ≤85% relative humidity

10. Transmission interface: USB

Features

1. The fisheye lens can automatically maintain a horizontal state: the small fisheye camera lens designed specifically for plant canopy structure measurement is installed on a handheld universal balance joint, which can automatically keep the lens in a horizontal state without a tripod;

2. The fisheye lens can be extended into the canopy: the lens is installed at one end of the rocker arm. Due to its small size and the measuring rod, it can be easily extended horizontally forward or vertically upward to different heights of the canopy, and quickly perform layered measurements to measure the vertical distribution of light transmittance and leaf area index in the group;

3. Image analysis software: The image analysis software can arbitrarily define the image analysis area (the zenith angle can be divided into 10 areas, and the azimuth angle can be divided into 10 areas).

4. The unreasonable canopy part can be shielded: when performing regional analysis of the canopy in different directions, the ground object scene and the unreasonable canopy part (such as missing plants, side row problems, etc.) can be arbitrarily shielded.

5. Automatic threshold adjustment to avoid subjective threshold setting and increase error

6. Data browsing: historical data can be browsed

7. Built-in Chinese and English bilingual display, one-click switching

Configuration list: fisheye probe, measuring rod, laptop (built-in analysis software), computer bag, dongle, aluminum box, manual, certificate of conformity