How to measure plant dimensions

Abstract

To provide a method for measuring plant dimensions in order to efficiently and accurately measure the dimensions of dimension measurement point of the stem of a plant by improving a method for image analysis of an imaged plant stem.SOLUTION: A background plate 3 on which dimension references are written is arranged behind the plant when the imager is used to image the predetermined dimension measurement point on the stem of the plant. The dimensions of the stem of the plant at the dimension measurement points are calculated based on data obtained at a plurality of points along the stem of the plant in the analysis of the image.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for measuring the dimensions of a plant. [Background technology]

[0002] Conventionally, as an example of a method for measuring the dimensions of a plant, a method for measuring the diameter of a plant stem by contacting the stem with a measuring tool such as a tape measure or a vernier caliper has been implemented. However, since the plant is contacted during measurement, there is a risk of negatively affecting the vegetative growth of the plant. Furthermore, when the point where the diameter of the plant stem is to be measured is a branched part of the plant, this part becomes an obstacle, making it difficult to contact the measuring tool.

[0003] As an example of a plant-related measurement method, a system is provided in which an imaging unit captures an image of a target plant from above and measures characteristics of the plant's stem through image analysis (see, for example, Patent Document 1). By measuring plants through image analysis in this way, simple and highly accurate measurement is possible, and measurement can be performed with little or no contact with the plant.

[0004] As a method for measuring the dimensions of plants using image analysis, a method has been proposed in which a white background board marked with a black marker is placed behind the plant when the plant is imaged. However, in reality, due to the three-dimensional nature of the plant caused by the presence of branches and leaves, it is difficult to place the plant stem in close contact with the white background board, and as a result, there are cases in which measurement errors occur due to the distance between the plant stem and the white background board. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-104037 A Summary of the Invention [Problem to be solved by the invention]

[0006] Regarding the above-mentioned measurement method, in order to evaluate the degree of vegetative growth of a plant, it is conceivable to place a white background board behind the plant, take an image of the plant stem with an imaging device such as a digital camera, and measure the diameter of the plant stem using a specified image analysis program. In this case, even though there is actually a distance between the plant stem and the background board, a value is calculated assuming that the plant stem is in close contact with the white background board. For this reason, the measured value of the diameter of the plant stem using the image analysis program often exceeds the true value. In addition, it is difficult to measure the distance between the plant stem and the white background board using the image analysis program.

[0007] In view of the above-mentioned measurement error problem, the present invention aims to provide a method for measuring the dimensions of a plant by improving the method for imaging the stem of the plant and reducing the error in the measured value of the diameter of the stem of the plant. The final aim of the present invention is to enable the management of the vegetative growth of the plant based on the highly reliable measured value of the diameter of the stem of the plant.

[0008] Here, in the method for measuring the dimensions of a plant in the present invention, the parameter to be measured may be other than the diameter of the plant stem. [Means for solving the problem]

[0009] To solve the above problems, the present invention provides: A background board was placed behind the plant, and the stem of the plant was photographed with the camera at a predetermined measurement point. A method for measuring dimensions of a plant to calculate the dimensions of the plant, comprising the steps of: The background plate has dimensional standards written on it; The dimension is measured at a plurality of points along the stem, and the dimension at the dimension measurement point is calculated based on data obtained from the plurality of points. A method for measuring the dimensions of plants. According to the present invention, it is possible to calculate the dimensions at the dimension measurement point from the overall shape of the plant stem based on measurements at multiple points, rather than calculating the dimensions from the measurements at one point at the dimension measurement point. As a result, it is possible to calculate the dimensions at the dimension measurement point with high accuracy. Note that the measurements at multiple points in the present invention are based on the same dimensional standard marked on the background board.

[0010] The present invention may also be a method for measuring the dimensions of a plant, characterized in that the dimension measurement point is a portion of the plant below a predetermined length from the growing point, the dimension is the diameter or width of the stem, and the dimension at the dimension measurement point is calculated by obtaining an approximation curve of the relationship between the dimension and the length from the growing point at the plurality of points and the dimensions measured at the plurality of points. According to this, the value of the dimension is obtained from the approximation curve of the relationship between the length from the growing point and the dimension, so that the reliability of the value is high. In the present invention, the predetermined length may be, for example, 20 cm.

[0011] The present invention may also be a method for measuring the dimensions of a plant, characterized in that the background plate is marked with a mark indicating the position reference of the growth point and a plurality of indicators arranged at a predetermined length from the mark. This makes it easier for the measurer to recognize the position of the growth point when imaging the plant with an imaging device. It also makes it easier for the measurer to recognize the position of the plant stem, which is the dimension measurement point, from the growth point. In the present invention, a plurality of indicators may be marked within a range of, for example, 30 cm below the mark indicating the position reference of the growth point.

[0012] The present invention may also be a method for measuring the dimensions of a plant, characterized in that the background plate has an upside-down T shape consisting of a horizontal portion that extends horizontally when placed behind the plant and a vertical portion that extends vertically from the horizontal center of the horizontal portion, the dimension reference is placed on a portion of the horizontal portion that horizontally sandwiches the vertical portion, and the mark and the indicator indicating the position reference of the growth point are aligned vertically on the vertical portion. According to this, since the background plate has an upside-down T shape, it is easy to place the background plate behind the stem of the plant. Furthermore, compared to a background plate having a rectangular shape, the upside-down T shape background plate can suppress the distance between the stem of the plant and the background plate in the front-back direction from becoming long due to the three-dimensional nature of the growth point of the plant caused by the presence of branches and leaves, and can improve the measurement accuracy of the dimensions of the stem of the plant.

[0013] The present invention may also be a method for measuring the dimensions of a plant, characterized in that, in imaging the dimension measurement location, a frame-shaped imaging mask is displayed on the imaging screen of the imaging device, and, during imaging, the dimension measurement location and the dimension reference are positioned at predetermined positions inside the imaging mask on the imaging screen of the imaging device, thereby determining the positional relationship between the dimension measurement location and the dimension reference. This makes it easier to position the stem of a plant when imaging the stem of the plant, and makes it possible to prevent measurement errors caused by being too close to the end. Effect of the Invention

[0014] According to the present invention, it is possible to measure the dimensions of a plant efficiently and with high accuracy, and it is possible to more accurately manage the cultivation of the plant based on the obtained dimensional values. For example, in the case of measuring the diameter of a plant's stem, it is possible to more accurately determine whether the level of nutritional growth of the plant is appropriate or inappropriate from the obtained value, and more accurately determine the amount of water and fertilizer to be supplied. This makes it possible to easily adjust the [Brief description of the drawings]

[0015] [Figure 1]FIG. 1 is a schematic diagram showing how an image of a plant stem is captured using an imaging device. [Diagram 2] 1 is a schematic diagram showing the surface features of a background plate having a reference mark for aligning the position of a plant's growing point and an indicator showing the length below the growing point. FIG. [Diagram 3] FIG. 13 is a schematic diagram for explaining a method for measuring the diameter of a plant stem using an image analysis program after imaging. [Figure 4] 1 is a schematic diagram showing an imaging mask in an imaging screen seen by a measurer when an image of a plant stem and a background board is captured by an imaging device. FIG. [Diagram 5] 11A and 11B are schematic diagrams showing modified examples of the shape of the background plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Application example] In this application example, a method for measuring the diameter of a plant stem will be described as an example of a method for measuring the dimensions of a plant. In measuring the diameter of a plant stem, in order to obtain more accurate information on the position coordinates of the target measurement point, there is a method in which a white background board on which markers whose distances from each other are known are placed behind the plant stem. With the background board placed behind the plant stem to be measured, the plant stem and the background board are imaged, and in analyzing the image, the position of each measurement point of the plant stem on the image is obtained with high accuracy based on the distance between the markers on the white background board, and the diameter of the plant stem at each measurement point is measured.

[0017] When analyzing the captured image using an image analysis program, the top end of the plant stem is taken as the growth point of the target plant, and the diameter of the stem is measured at multiple points along the stem. An approximation curve equation is found from the data at multiple points, and the diameter of the stem, for example, 20 cm below the growth point, can be calculated using the approximation curve equation.

[0018] Example 1 Hereinafter, a plant dimension measuring method according to a first embodiment of the present invention will be described in detail with reference to the drawings. In the following, measurement of the diameter of a plant stem will be described as an example of measuring the plant dimension.

[0019] <Dimensional measurement method> FIG. 1 is a schematic diagram showing how a plant stem 2 is imaged using an imaging device 1. For example, a digital camera or the like is often used as the imaging device 1. A background board 3 is placed behind the plant stem 2, and the plant stem 2 is imaged using the imaging device 1. The measurement point is identified by image analysis, and the diameter of that part is measured. The background board 3 is often white, but it need only be a color similar to that of the plant stem 2 so that it can be distinguished from the plant stem 2. The width of the plant stem 2 is calculated based on the distance between markers 5 (not shown) placed on the background board 3, and the diameter is calculated from the width of the plant stem 2. Here, the growing point of the plant refers to a part at the tip of the plant stem where cell division is active.

[0020] In measuring the diameter of the plant stem 2, specifically, the diameter at 20 cm below the plant's growth point is stable, and the diameter measured at this position is highly reliable as the true value of the diameter of the plant stem 2. When taking an image using the imaging device 1 and analyzing using an image analysis program, it is desirable for the person making the measurement to be able to recognize the portion 20 cm below the growth point (hereinafter, this portion will also be referred to as the dimension measurement portion). A measurement line 8 (not shown) is marked on the background board 3, but this is used as a scale for auxiliary length measurement. In this embodiment, during analysis, the diameter of the plant stem 2 is measured at each predetermined length from the growth point, and an approximation curve is obtained from these values ​​to determine the diameter at the dimension measurement portion 20 cm below the growth point. Note that the shape of the surface of the background board 3 is shown as a rectangle. However, the shape is not limited to a rectangle.

[0021] Next, in this embodiment, when imaging a plant stem 2 using the imaging device 1, a background board is used in addition to the background board 3 shown in Figure 1, which has a reference mark for aligning the position of the plant's growth point and an indicator showing the length below the plant's growth point, as described below.

[0022] <Dimensional measurement method> FIG. 2 is a schematic diagram showing the surface characteristics of a background plate 3 having a mark serving as a reference for aligning the position of the growth point of a plant and an indicator showing the length below the growth point. As described above, the measurement of dimensions such as the diameter of a plant stem 2 is performed by placing the background plate 3 shown in FIG. 2 behind the plant, capturing an image of the plant with the camera 1, and analyzing the image after capturing the image. The background plate 3 has marker areas 4 in two places, the upper right and the upper left in the orientation of FIG. 2, and has multiple markers 5 in each of the marker areas 4. The orientation of the background plate 3 when capturing the image does not matter. The markers 5 may be placed on the lower end side in the orientation of FIG. 2. Here, the markers 5 correspond to the dimensional reference in the present invention.

[0023] In an image of a plant stem 2 captured with a background board 3 placed behind it, the reference position coordinates of the multiple markers 5 are determined in advance, and the diameter of the plant stem 2 can be measured from the number of pixels between the multiple markers 5 and the number of pixels in the width of the target plant stem 2. The distance between the markers 5, indicated as W in FIG. 2, is, for example, 30 cm. The shape of the marker 5 is often a circle filled with black. At least one marker 5 is required in each of the two marker areas 4. When capturing an image using the imaging device 1, the marker area 4 is set so that it is completely within the capture range. When capturing an image, the marker area 4 is set so that a shadow does not overlap it.

[0024] A growing point position point 6 is marked on the background board 3, and when the plant stem 2 is imaged, the position of the plant's growing point is aligned with the growing point position point 6. Furthermore, measurement indicators 7a to 7d are marked on the background board 3, and the distances from the growing point position point 6 to each measurement indicator are 10 cm, 15 cm, 20 cm, and 30 cm, respectively. In an analysis using an image analysis program, a position 20 cm below the growing point is the dimension measurement point of the plant stem 2, and when the plant is imaged by the imaging device 1, the person measuring can recognize the position of the measurement indicator 7c and use it as a guide for the dimension measurement point. Here, the measurement indicators 7a to 7d correspond to the indicators in the present invention.

[0025] The background board 3 also has measurement lines 8, which can be used to measure, for example, the width of the leaves of a plant. Note that the solid lines that intersect vertically vertically and horizontally on the background board 3 shown in Fig. 2 are all measurement lines, and scales used to assist in dimensional measurement are actually displayed, but are omitted in Fig. 2. Also, when capturing an image, as long as the marker area 4 is within the capturing range, the plant does not need to be positioned in the center, and the image may be captured at an angle.

[0026] FIG. 3 is a schematic diagram for explaining a method of measuring the diameter of a plant stem 2 using an image analysis program after imaging. Here, the image analysis program is a program prepared for calculating the diameter of the plant stem 2 at a dimension measurement point from an image including the plant stem 2 and a background board 3 captured by the imaging device 1. The image analysis program may be loaded into a general PC (not shown), stored in a memory such as a ROM of the PC, and executed by the CPU of the PC. When the imaging device 1 is a general digital camera, the image captured by the imaging device 1 is imported into the PC, and the image is called and analyzed by the image analysis program. When the imaging device 1 is, for example, a smartphone or a tablet PC, the image analysis program may also be loaded into the smartphone or tablet PC, and the image may be analyzed as it is after it is captured. FIG. 3(a) is a schematic diagram of a captured image of a plant stem 2. Image By executing the image analysis program and tracing downward from the top end of the captured plant in the direction of the plant stem 2, the traced path is displayed on the image. The traced path is displayed as a thick line as shown in Figure 3(a). The starting point of the traced path is set as the growth point of the plant, and the measurement point of the plant stem 2 is set to a part 20 cm below the growth point.

[0027] In the image analysis program, the diameters of the stems corresponding to the multiple points on the locus are measured to calculate the diameter of the stems 2 at the dimension measurement points. More specifically, the distances (number of pixels) between the ends of the stems on both sides of the multiple points on the locus in the horizontal direction are found based on the distances (number of pixels) between the markers 5 on the background board 3. The diameters of the stems corresponding to the multiple points are obtained by multiplying the found number of pixels by the pitch between the pixels.

[0028] Next, in the analysis using the image analysis program, as shown in FIG. 3(b), the values ​​of the stem diameter corresponding to the value of L at multiple points selected above and below each of the measurement indicators 7a to 7d shown in FIG. 3(a) are displayed fragmentarily as dots on the graph of the approximation curve. Then, an approximation curve is obtained from the displayed points, and the values ​​of the stem diameter corresponding to all values ​​of L are displayed together with the dots. Furthermore, the diameter of the stem when L=20 is calculated from the approximation curve as the measured value of the diameter of the plant stem 2. This is because the diameter of the stem at the dimension measurement point 20 cm below the growth point is highly reliable as a measured value of the stem diameter. In this way, by calculating the diameter of the stem at the dimension measurement point 20 cm below the growth point based on the data at multiple points, a more reliable value can be obtained. In this case, it is not necessary to include the measurement at the position using the measurement indicator 7c as a guide, and for example, the approximation curve may be obtained from multiple points using the measurement indicators 7b and 7d as guides, and the stem diameter at the dimension measurement point where L=20 may be calculated. The approximation curve may also be obtained from multiple other points. In this case, it is preferable to select a plurality of points above and below the dimension measurement point of L=20. This improves the accuracy of calculating the diameter at L=20. In addition, the approximation curve in this embodiment is a quartic function y=2E -08 x 4 -2E -05 x 3 +0.006x 2 An example would be -0.7284x+35.473.

[0029] In addition, when imaging, the stem 2 of the plant may overlap with the branches and leaves of the plant, and in the analysis, the stem 2 of the overlapping part of the plant may not be recognized, and the continuous stem 2 of the plant may be recognized as interrupted. Therefore, as a correction, it is possible to write a straight line or a spline curve into the analysis image later. In this way, in the image analysis, it is possible to recognize the stem 2 of the plant as continuous.

[0030] Figure 4 is a schematic diagram showing an imaging mask 9 in the imaging screen seen by the measurer when the imaging device 1 images the stem 2 of the plant and the background plate 3. In the imaging screen, since the alignment of the stem 2 of the plant is important, in order to facilitate it, a double-character "king" - shaped imaging mask 9 is displayed. Although shown simply in FIG. 4, only the inside of the frame of the imaging mask 9 is bright, and the outside of the frame is shaded and cannot be clearly seen by the measurer. It is a necessary condition at the time of imaging that the stem 2 of the plant and the marker area 4 are within the frame of the imaging mask 9. In this embodiment, in this way, when imaging by the imaging device 1, the imaging mask 9 is displayed on the imaging screen seen by the measurer, and by arranging the stem 2 of the plant and the marker area 4 within its frame, the positional relationship between the stem 2 of the plant and the background plate 3 can be easily determined, and the measurement accuracy of the diameter of the stem 2 of the plant can be improved. Note that the imaging mask 9 is merely a tool for facilitating the alignment of the stem 2 of the plant and is not necessarily essential in the imaging screen. Also, the shape of the imaging mask 9 does not have to be "king" - shaped as long as the stem 2 of the plant and the marker area 4 are within its frame, and for example, it may be "T" - shaped. It does not have to be in the shape of a character such as a "+" shape.

[0031] 〔Example 2〕 Next, Example 2 of the present invention will be described. In this example, when imaging the stem 2 of the plant using the imaging device 1, a background plate with a small surface area compared to the background plate 3 shown in Example 1 and in the shape of an upside - down "T" is used. Note that the background plate in the shape of an upside - down "T" is merely an example in this example and is not intended to limit the shape of the background plate. Hereinafter, the background plate in the shape of an upside - down "T" is regarded as corresponding to the background plate 3 of Example 1 and is simply referred to as the background plate 3.

[0032] FIG. 5 is a schematic diagram showing a modified shape of the background plate 3. The background plate 3 has a shape of an upside-down T, and when placed behind the plant stem 2 during imaging, it has a horizontal part that extends horizontally and a vertical part that extends vertically from the horizontal center of the horizontal part. Markers 5 are written on both ends of the horizontal part so as to sandwich the vertical part. The vertical part has a vertical row of growth point position points 6 and measurement indicators 7a to 7d. The background plate 3 in the shape of an upside-down T has a smaller surface area than the rectangular background plate 3 with the same vertical and horizontal widths, and can suppress the increase in the distance between the plant stem 2 and the background plate 3 in the front-to-back direction due to the three-dimensional nature of the plant's growth point caused by the presence of branches and leaves, making it possible to calculate the diameter of the dimension measurement point of the plant stem 2 with high reliability.

[0033] The dimension measuring method shown in this embodiment makes it possible to measure the diameter of the plant stem 2 with high accuracy without almost contacting the plant stem 2 other than for the purpose of fixing the plant stem 2. Generally, it is necessary for a plant to achieve an optimal growth balance for each growth stage, and measuring the diameter of the plant stem 2 is one of the indicators for managing the vegetative growth required for the growth balance. In the above embodiment, an example of measuring the diameter of the plant stem as the dimension of the plant stem has been described, but the dimension to be measured may be the radius or width of the plant. In addition, the approximation curve for calculating the diameter at the dimension measurement point from the diameter values ​​at multiple points in the image analysis program is not limited to the above-mentioned curve. Polynomials other than quartic functions, exponential functions, logarithmic functions, trigonometric functions, predetermined spline functions, and other functions may be used.

[0034] In the following, the components of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the components of the present invention with the configurations of the embodiments. <Invention 1> A method for measuring dimensions of a plant, comprising the steps of: placing a background plate (3) behind the plant; and calculating dimensions of a predetermined measurement point of a stem (2) of the plant captured by an image capture device (1), the method comprising the steps of: The background plate is marked with dimensional standards (5); The dimension is measured at a plurality of points along the stem, and the dimension at the dimension measurement point is calculated based on data obtained from the plurality of points. How to measure plant dimensions. [Explanation of symbols]

[0035] 1: Camera 2: Plant stem 3:Background board 4: Marker area 5: Marker 6: Growing point location point 7a-7d: Measurement index 8: Survey line 9: Image capture mask

Claims

1. A method for measuring dimensions of a plant, comprising the steps of: placing a background board behind the plant; and calculating dimensions of a predetermined measurement point of a stem of the plant captured by an image capture device, the method comprising the steps of: The dimension measurement location is a portion of the plant below a predetermined length from a growth point of the plant, The background plate has dimensional standards written on it; the dimension being the diameter or width of the stem, The dimension is measured at a plurality of points along the stem; The dimension at the dimension measurement point is calculated by obtaining an approximation curve of the relationship between the dimension and the length from the dimension measured at the multiple points and the length from the growth point at the multiple points. How to measure plant dimensions.

2. The background plate is provided with a mark indicating a position reference of the growth point and a plurality of indicators arranged at a predetermined length from the mark. The method for measuring dimensions of a plant according to claim 1.

3. the background board has an upside-down T-shape including a horizontal portion that extends horizontally when placed behind the plant and a vertical portion that extends vertically from a horizontal center of the horizontal portion; the dimensional reference is disposed on a portion of the horizontal portion that horizontally sandwiches the vertical portion, The mark indicating the position reference of the growth point and the indicator are arranged in parallel in a vertical direction on the vertical portion. The method for measuring dimensions of a plant according to claim 2.

4. displaying a frame-shaped imaging mask on an imaging screen of the imaging device in imaging the dimension measurement location; and determining a positional relationship between the dimension measurement location and the dimension reference by arranging the dimension measurement location and the dimension reference at a predetermined position inside the imaging mask on an imaging screen of the imaging device during imaging. A method for measuring dimensions of a plant according to any one of claims 1 to 3.

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