CN1952599A

CN1952599A - A flat leaf area nondestructive measuring system and method thereof

Info

Publication number: CN1952599A
Application number: CN 200510086647
Authority: CN
Inventors: 滕军; 胡包钢
Original assignee: Institute of Automation of Chinese Academy of Science
Current assignee: Institute of Automation of Chinese Academy of Science
Priority date: 2005-10-20
Filing date: 2005-10-20
Publication date: 2007-04-25
Anticipated expiration: 2025-10-20
Also published as: CN100443856C

Abstract

The invention relates to the field of plane area measurement technology, in particular to the non-destructive measurement system and method of the plane blade area for a single image. The system comprises: image acquisition unit, image correction unit, blade image division unit, blade area calculation unit. The method includes: the flat blade image which is attached to the demarcating board can be gained from the image acquisition unit; the projective corresponding relationship between the image element and the object can be calculated based on the isonym point of the image and the demarcating board by the image correction unit, the orthographic correction of the image is also done; the image of the blade can be separated from the background by the blade image division unit; the area of the blade image which is after the orthographic correction can be computed based on the projective corresponding relationship by the blade area calculation unit.

Description

A non-destructive measurement system and method for planar blade area

技术领域technical field

本发明涉及平面面积测量技术领域，特别是一种使用单幅图像，进行平面叶片面积无损测量系统及其方法。The invention relates to the technical field of plane area measurement, in particular to a system and method for nondestructively measuring plane blade area by using a single image.

背景技术Background technique

叶片面积是作物栽培和育种操作的常用指标之一，也是农作物产量和品质的重要评价指标。关于叶片面积的测量一直是农业领域中的热点之一。现有的传统叶面积测量方法，包括利用方格板测量叶面积法、利用叶重量估计叶面积法、利用回归方程计算叶面积法，分别存在着操作复杂费时、破坏叶片和单个叶片测量误差大的缺点。而利用进口的叶面积仪测定叶面积，虽然操作简单快速，结果准确，但是价格昂贵，不适宜普遍推广应用。Leaf area is one of the commonly used indicators in crop cultivation and breeding operations, and is also an important evaluation indicator for crop yield and quality. The measurement of leaf area has always been one of the hotspots in the field of agriculture. Existing traditional leaf area measurement methods, including the method of measuring leaf area by grid plate, the method of estimating leaf area by using leaf weight, and the method of calculating leaf area by regression equation, respectively have complex and time-consuming operations, damaged leaves, and large measurement errors for individual leaves. Shortcomings. However, the imported leaf area meter is used to measure the leaf area, although the operation is simple and quick, and the result is accurate, but the price is expensive, and it is not suitable for widespread application.

一种替代方法是使用扫描仪将叶片进行扫描，然后计算叶片面积，但是这种方法只能进行破坏性测量。An alternative is to use a scanner to scan the leaf and calculate the leaf area, but this method is only destructive.

发明内容Contents of the invention

本发明的目的在于无特殊昂贵的扫描仪器的条件下，准确、快速地对单个叶片进行面积测量和分析，从而获得相关的叶片面积、叶片周长、叶片长度、叶片宽度和叶片长宽比等相关参数。本发明的目的旨在为用户提供一个价格便宜、操作简单、测量结果准确的叶片面积测量系统。The object of the present invention is to accurately and quickly measure and analyze the area of a single blade without special and expensive scanning instruments, so as to obtain relevant blade area, blade circumference, blade length, blade width and blade aspect ratio, etc. Related parameters. The purpose of the present invention is to provide users with a blade area measurement system with low price, simple operation and accurate measurement results.

本发明使用自行设计的印刷电路板(PCB)作为标定板，通过单幅图像，进行处理，从而计算得出叶片面积。不需要相机定标和图像匹配这些可以带来误差的步骤。同时由于系统构成所用的部件，使得其成本得到控制。在保证成本的同时，系统可以达到0.5％的重复测量精度，满足了绝大部分的测量需要。The present invention uses a self-designed printed circuit board (PCB) as a calibration board, processes a single image, and calculates the blade area. Error-inducing steps such as camera calibration and image matching are not required. At the same time, due to the components used in the system, the cost is controlled. While ensuring the cost, the system can achieve a repeated measurement accuracy of 0.5%, which meets most of the measurement needs.

$(\begin{matrix} {X x}_{u u}^{Ob Ob} & {X x}_{v v}^{Ob Ob} & 11 & 00 & 00 & 00 & - - {X x}_{u u}^{Ob Ob} \cdot \cdot {X x}_{t t}^{Im Im} & - - {X x}_{u u}^{Ob Ob} \cdot \cdot {X x}_{t t}^{Im Im} \\ 00 & 00 & 00 & {X x}_{u u}^{Ob Ob} & {X x}_{v v}^{Ob Ob} & 11 & - - {X x}_{j j}^{Im Im} \cdot \cdot {X x}_{u u}^{Ob Ob} & - - {X x}_{j j}^{Im Im} \cdot \cdot {X x}_{v v}^{Ob Ob} \end{matrix}) \cdot \cdot (\begin{matrix} {m m}_{1111} \\ {m m}_{1212} \\ {m m}_{1313} \\ {m m}_{21 twenty one} \\ {m m}_{22 twenty two} \\ {m m}_{23 twenty three} \\ {m m}_{3131} \\ {m m}_{3232} \end{matrix}) = = (\begin{matrix} {X x}_{t t}^{Im Im} \\ {X x}_{j j}^{Im Im} \end{matrix})$

图像校正单元计算射影矩阵公式。其中(x_u ^Ob，x_v ^Ob)的物体坐标，(x_i ^Im，x_j ^Im)是对应的像素坐标，公式给出了这两个点之间的射影关系。给出4个(x_u ^Ob，x_v ^Ob)，(x_i ^Im，x_j ^Im)对，就可以求解(m₁₁，m₁₂，m₁₃，m₂₁，m₂₂，m₂₃，m₃₁，m₃₂)。考虑到误差的因素，用户可以给出多于4个(x_u ^Ob，x_v ^Ob)，(x_i ^Im，x_j ^Im)对，图像校正单元会采用SVD方法求出最优的(m₁₁，m₁₂，m₁₃，m₂₁，m₂₂，m₂₃，m₃₁，m₃₂)。所以用户要建立是用户配置文件，在其中中给出(x_u ^Ob，x_v ^Ob)，并且在图像中选取对应的(x_i ^Im，x_j ^Im)。The image correction unit calculates a projective matrix formula. Where (x _u ^Ob , x _v ^Ob ) is the object coordinate, (x _i ^Im , x _j ^Im ) is the corresponding pixel coordinate, and the formula gives the projective relationship between these two points. Given 4 (x _u ^Ob , x _v ^Ob ), (x _i ^Im , x _j ^Im ) pairs, we can solve (m ₁₁ , m ₁₂ , m ₁₃ _, m _{21 , m 22} , m ₂₃ , m ₃₁ , m ₃₂ ). Considering the error factor, the user can give more than 4 (x _u ^Ob , x _v ^Ob ), (x _i ^Im , x _j ^Im ) pairs, and the image correction unit will use the SVD method to find the optimal (m ₁₁ , m ₁₂ , m ₁₃ , m ₂₁ , m ₂₂ , m ₂₃ , m ₃₁ , m ₃₂ ). Therefore, the user needs to create a user configuration file, in which (x _u ^Ob , x _v ^Ob ) is given, and the corresponding (x _i ^Im , x _j ^Im ) is selected in the image.

${x x}_{i i}^{Im Im} = = \frac{{m m}_{1111} \cdot &Center Dot; {X x}_{u u}^{Ob Ob} + + {m m}_{1212} \cdot &Center Dot; {X x}_{ν ν}^{Ob Ob} + + {m m}_{1313}}{{m m}_{3131} \cdot &Center Dot; {X x}_{u u}^{Ob Ob} + + {m m}_{3232} \cdot \cdot {X x}_{ν ν}^{Ob Ob} + + 11}$

${x x}_{j j}^{Im Im} = = \frac{{m m}_{21 twenty one} \cdot &Center Dot; {X x}_{u u}^{Ob Ob} + + {m m}_{22 twenty two} \cdot \cdot {X x}_{ν ν}^{Ob Ob} + + {m m}_{23 twenty three}}{{m m}_{3131} \cdot \cdot {X x}_{u u}^{Ob Ob} + + {m m}_{3232} \cdot \cdot {X x}_{ν ν}^{Ob Ob} + + 11}$

图像坐标和物体坐标的关系，其中，(x_i ^Im，x_j ^Im)是像素坐标，(x_u ^Ob，x_v ^Ob)是物体坐标，(m₁₁，m₁₂，m₁₃，m₂₁，m₂₂，m₂₃，m₃₁，m₃₂)是图像校正单元计算出的8个常数。对于图像上的每个像素，这个公式给出了其在标定板上的坐标系上的真实坐标。The relationship between image coordinates and object coordinates, where (x _i ^Im , x _j ^Im ) is the pixel coordinates, (x _u ^Ob , x _v ^Ob ) is the object coordinates, (m ₁₁ , m ₁₂ , m ₁₃ , m ₂₁ , m ₂₂ , m ₂₃ , m ₃₁ , m ₃₂ ) are eight constants calculated by the image correction unit. For each pixel on the image, this formula gives its true coordinates on the coordinate system on the calibration plate.

技术方案Technical solutions

本发明的目的是通过下述技术方案实现的：The purpose of the present invention is achieved through the following technical solutions:

该系统包括图像采集单元，图像校正单元，叶片图像分割单元，叶片面积计算单元。The system includes an image acquisition unit, an image correction unit, a leaf image segmentation unit, and a leaf area calculation unit.

通过图像采集装置得到附着在标定板上的平面叶片图像，对于拍照的数码相机没有特定的要求。The image of the plane leaf attached to the calibration plate is obtained by the image acquisition device, and there is no specific requirement for the digital camera that takes pictures.

图像校正装置根据图像和标定板上的同名点，计算出图像上的像素和实际物体的射影对应关系。The image correction device calculates the projective correspondence between the pixels on the image and the actual object according to the same-named points on the image and the calibration plate.

叶片图像分割装置将叶片的图像从背景中分离出来。The leaf image segmentation device separates the image of the leaf from the background.

叶片面积计算装置根据射影对应关系，计算出校正后的叶片图像的面积。The blade area calculation device calculates the area of the corrected blade image according to the projective correspondence.

图像采集模块由标定板、相机、相机控制软件模块组成，图像校正单元、叶片图像分割单元、叶片面积计算单元为软件模块，集成在一个单元，其中，图像采集单元，图像校正单元，叶片图像分割单元，叶片面积计算单元，上述单元依次顺序连接。The image acquisition module is composed of a calibration board, a camera, and a camera control software module. The image correction unit, the leaf image segmentation unit, and the leaf area calculation unit are software modules that are integrated into one unit. Among them, the image acquisition unit, the image correction unit, and the leaf image segmentation unit, a blade area calculation unit, and the above units are sequentially connected.

一种平面叶片面积无损测量方法，其步骤如下：A method for non-destructive measurement of plane blade area, the steps are as follows:

通过图像采集单元得到附着在标定板上的平面叶片图像；The image of the plane blade attached to the calibration plate is obtained through the image acquisition unit;

图像校正单元根据图像和标定板上的同名点，计算出图像上的像素和实际物体的射影对应关系；The image correction unit calculates the projective correspondence between the pixels on the image and the actual object according to the same name point on the image and the calibration plate;

叶片图像分割单元将叶片的图像从背景中分离出来；The blade image segmentation unit separates the image of the blade from the background;

叶片面积计算单元根据射影对应关系，计算出正射校正后的叶片图像的面积。The blade area calculation unit calculates the area of the blade image after orthorectification according to the projective correspondence.

附图说明Description of drawings

图1是标定板及所拍摄的照片图。Figure 1 is the calibration board and the photos taken.

图2是本发明的平面叶片面积无损测量系统图。Fig. 2 is a diagram of the non-destructive measurement system for plane blade area of the present invention.

图3是本发明的平面叶片面积无损测量方法流程图。Fig. 3 is a flow chart of the method for non-destructive measurement of plane blade area of the present invention.

具体实施方式Detailed ways

图1是标定板及所拍摄的照片，图中为待测叶片附着在标定板上。Figure 1 is the calibration plate and the photos taken, in which the blade to be tested is attached to the calibration plate.

图2平面叶片面积无损测量系统包括图像采集装置，图像校正装置，叶片图像分割装置，叶片面积计算装置。其中，图像采集单元，图像校正单元，叶片图像分割单元，叶片面积计算单元，上述单元依次顺序连接。Fig. 2 The planar blade area non-destructive measurement system includes an image acquisition device, an image correction device, a blade image segmentation device, and a blade area calculation device. Wherein, the image acquisition unit, the image correction unit, the leaf image segmentation unit, and the leaf area calculation unit are sequentially connected to each other.

图3平面叶片面积无损测量方法的具体操作过程为：The specific operation process of the non-destructive measurement method of plane blade area in Fig. 3 is:

(1)将待测量的叶片附着在标定板上，展平，使用数码相机拍摄一幅标定板图像；(1) Attach the blade to be measured to the calibration plate, flatten it, and use a digital camera to take an image of the calibration plate;

(2)用户建立与图像同名点对应的物体坐标文件；(2) The user creates an object coordinate file corresponding to the point with the same name in the image;

(3)装入图像和对应的同名点文件；(3) Load image and corresponding point file with the same name;

(4)用户通过3种方法进行叶片图像的分割(4) The user divides the leaf image by 3 methods

RGB(红、绿、蓝)色彩空间分割：用户指定种子像素和容差，叶片图像分割单元会自动从种子像素开始，把和种子像素颜色相近并且拓扑上具有相邻关系的像素分离出来；RGB (red, green, blue) color space segmentation: the user specifies the seed pixel and tolerance, and the blade image segmentation unit will automatically start from the seed pixel to separate the pixels that are similar in color to the seed pixel and have a topologically adjacent relationship;

HSI(色度、饱和度、亮度)色彩空间分割：方法同RGB色彩空间分割，只是色彩空间的选区为HSI空间。HSI (hue, saturation, brightness) color space segmentation: the method is the same as that of RGB color space, except that the selection area of color space is HSI space.

多边形分割：用户使用多边形框住叶片图像，叶片图像分割单元会自动对多边形内部进行填充，分割出叶片图像。Polygonal segmentation: the user uses a polygon to frame the leaf image, and the leaf image segmentation unit will automatically fill the interior of the polygon to segment the leaf image.

(5)用户通过软件用户界面，进行图像正射校正；(5) The user performs image orthorectification through the software user interface;

(6)用户通过软件用户界面，进行叶片面积计算。(6) The user calculates the blade area through the software user interface.

平面叶片面积无损测量方法，可以采用三种不同的方法及其组合分割出叶片图像，从而得到精确的叶片面积结果。The plane leaf area non-destructive measurement method can use three different methods and their combinations to segment the leaf image, so as to obtain accurate leaf area results.

发明特点Invention Features

本系统是通过单幅图像，对于平面叶片面积进行无损测量的系统，其特点是：This system is a system for non-destructive measurement of the plane blade area through a single image, and its characteristics are:

1、通过单幅图像进行平面叶片面积测量，避免了相机定标和图像匹配，减小了误差。1. Measure the plane leaf area through a single image, avoiding camera calibration and image matching, and reducing errors.

2、由于系统的构成没有使用昂贵的器件，因此整个系统的硬件成本控制在300元以内。2. Since the system does not use expensive devices, the hardware cost of the whole system is controlled within 300 yuan.

3、使用印刷电路板及其上面的丝网层作为标定的尺度，由于其自身的精度，保证了系统的精度。3. Using the printed circuit board and the silk screen layer on it as the calibration scale, due to its own precision, the accuracy of the system is guaranteed.

4、采用多种图像分割的方法组合分割叶片图像，保证了计算的精度。4. Multiple image segmentation methods are used to combine and segment leaf images to ensure the accuracy of calculation.

5、用先计算，后校正的方法，系统具有可扩展性，不仅可以精确计算平面叶片面积，而且可以在图像上直接测量出长度，角度等几何量。5. With the method of calculating first and then correcting, the system is scalable, not only can accurately calculate the plane blade area, but also can directly measure geometric quantities such as length and angle on the image.

Claims

1. A non-destructive measurement system for plane blade area, characterized in that: the system includes an image acquisition unit, an image correction unit, a blade image segmentation unit, and a blade area calculation unit,

Obtain the plane leaf image attached to the calibration plate through the image acquisition unit,

The image correction unit calculates the projective correspondence between the pixels on the image and the actual object according to the same name point on the image and the calibration plate,

The blade image segmentation unit separates the image of the blade from the background,

The blade area calculation unit calculates the area of the blade image after orthorectification according to the projective correspondence,

The image acquisition module is composed of a calibration board, a camera, and a camera control software module. The image correction unit, the leaf image segmentation unit, and the leaf area calculation unit are software modules that are integrated into one unit. Among them, the image acquisition unit, the image correction unit, and the leaf image segmentation unit, a blade area calculation unit, and the above units are sequentially connected.

2. A method for non-destructive measurement of plane blade area, the steps of which are as follows:

The image of the plane blade attached to the calibration plate is obtained through the image acquisition unit;

The image correction unit calculates the projective correspondence between the pixels on the image and the actual object according to the same name point on the image and the calibration plate;

The blade image segmentation unit separates the image of the blade from the background;

The blade area calculation unit calculates the area of the blade image after orthorectification according to the projective correspondence.

3. The method for non-destructive measurement of plane blade area according to claim 2, wherein the specific steps are as follows:

(1) Attach the blade to be measured to the calibration plate, flatten it, and take an image of the calibration plate;

(2) The user creates an object coordinate file corresponding to the point with the same name in the image;

(3) Load image and corresponding point file with the same name;

(4) The user divides the leaf image through three methods;

(5) The user performs image orthorectification through the software user interface;

(6) The user calculates the blade area through the software user interface.

4. The non-destructive measurement method for planar leaf area according to claim 3, characterized in that three different methods and combinations thereof can be used to segment the leaf image, so as to obtain accurate leaf area results.

5. The method for non-destructive measurement of plane blade area according to claim 3 or 4, wherein the segmentation of the blade image in step (4) comprises:

RGB color space segmentation: the user specifies the seed pixel and tolerance, and the leaf image segmentation unit will automatically start from the seed pixel to separate the pixels that are similar in color to the seed pixel and have a topologically adjacent relationship;

HIS color space segmentation: the method is the same as RGB color space segmentation, but the color space adopts HSI space;

Polygon segmentation: the user uses a polygon to frame the leaf image, and the leaf image segmentation unit will automatically fill the interior of the polygon to segment the leaf image.