阅读说明：本技术 一种料流计量检测方法及系统 (Material flow metering detection method and system ) 是由 董霄剑 曾洪庆 于 2019-05-28 设计创作，主要内容包括：一种料流计量检测方法包括线激光投到传送带上物料；双目相机拍带线激光物料图像,得物料即时轮廓激光线；用线激光双目测量方法得即时轮廓激光线三维数据；传送带匀速运动,用线激光双目测量方法得各即时轮廓激光线三维数据,得三维数据组、点云数据；依点云数据确定数据边界,基于XOY平面将点云数据划为小域均匀采样,记采样点三维坐标；以小域面积为底面积采样点Z值为高算采样长方体体积；合计各采样长方体体积得物料体积。检测系统包括传送带、线激光发射器、双目相机、数据处理模块。本发明稳定获取料流轮廓激光线扫描处三维数据；采样及积分计算,减小体积计算误差；随传送带运行状态即时计量,实时性好；设备安装方便,简单易用,适用性广。(A material flow measuring and detecting method comprises the steps that linear laser is thrown to materials on a conveying belt; shooting a laser material image with a line by using a binocular camera to obtain a material instant profile laser line; obtaining real-time contour laser line three-dimensional data by using a line laser binocular measurement method; the conveyor belt moves at a constant speed, and real-time profile laser line three-dimensional data are obtained by a line laser binocular measurement method to obtain a three-dimensional data set and point cloud data; determining a data boundary according to the point cloud data, dividing the point cloud data into small domains based on an XOY plane for uniform sampling, and recording three-dimensional coordinates of sampling points; taking the small domain area as the bottom area, and taking the Z value of the sampling point as the height value to sample the volume of the cuboid; the volume of each sampling cuboid is summed to obtain the volume of the material. The detection system comprises a conveyor belt, a line laser transmitter, a binocular camera and a data processing module. The method stably obtains three-dimensional data at the position of material flow profile laser line scanning; sampling and integral calculation, and reducing volume calculation error; the measurement is carried out in real time along with the running state of the conveyor belt, and the real-time performance is good; the equipment is convenient to install, simple and easy to use, and wide in applicability.)

1. A method for measuring and detecting the flow of a material is characterized by comprising the following steps: projecting line laser to the material to be detected on the conveyor belt; a binocular camera is used for shooting a material image with line laser to obtain a material instant profile laser line; obtaining real-time contour laser line three-dimensional data by using a line laser binocular measurement method; the conveyor belt moves at a constant speed, and real-time profile laser line three-dimensional data are obtained by using a line laser binocular measurement method to obtain a three-dimensional data set so as to form point cloud data; determining a data boundary according to the point cloud data, dividing the point cloud data into micro areas based on an XOY plane, uniformly sampling, and recording three-dimensional coordinates of sampling points; calculating the volume of the sampling cuboid by taking the area of the micro region as the bottom area and the Z value of the sampling point as the height; and summing the volumes of the sampling cuboids to obtain the volume of the material passing through the line laser scanning part.

2. The line laser binocular measuring method of claim 1, comprising: carrying out three-dimensional calibration on the binocular camera; respectively acquiring a left material image and a right material image of the laser with lines through a left camera and a right camera of a binocular camera; performing stereo correction on the acquired left image and right image to align the corrected left image and right image; matching the corrected left image and the corrected right image to obtain a linear laser imaging matching point pair; and obtaining left and right image parallax according to the line laser imaging matching point pairs, and calculating three-dimensional material contour data at the laser line projection position according to the left and right image parallax.

3. The method of claim 1, wherein determining data boundaries from the point cloud data, partitioning the point cloud data into micro-regions based on an XOY plane and performing uniform sampling, and recording three-dimensional coordinates of sampling points comprises: determining a maximum data boundary according to the point cloud data, uniformly sampling the point cloud data in the boundary region based on an XOY plane, taking a point which is closest to the center of a sampling region in the sampling region as a sampling point, wherein a sampling interval delta D is a x D, and D is the maximum boundary length; where a is a constant less than 1 and the smaller a, the smaller the sampling interval, the smaller the sampling area, and the more accurate the calculation of the volume of the stream.

4. A material flow measurement sensing system, comprising: conveyer belt, line laser emitter, binocular camera, data processing module, wherein:

the conveyor belt moves at a constant speed, and conveyed materials are metered by the material flow metering and detecting system;

the line laser emitter projects line laser to the conveyor belt and materials on the conveyor belt so as to obtain instant profile laser lines of the materials;

the method comprises the following steps that a binocular camera acquires a left material image and a right material image of a strip line laser, and parameters of a left camera and parameters of a right camera of the binocular camera are the same;

the data processing module analyzes and processes the left image and the right image of the material with the laser to obtain three-dimensional data of the material profile at the laser line projection position;

the line laser emitter projects line laser perpendicular to the conveying plane of the conveyor belt.

Technical Field

The invention belongs to the technical field of material flow detection, and particularly relates to a material flow measurement detection method and a material flow measurement detection system.

Background

In the fields of food, medicine, agricultural products and industrial production, the conveying and metering of irregularly scattered granular or powdery solid materials are widely involved. In actual production, the metering of the granular or powdery solid materials is generally measured by adopting a weighing sensor weighing mode. The electronic belt scale is often used in the material conveying process to measure by adopting the weighing sensor principle, and signals of the weighing sensor are easily interfered when a belt runs, so that the measuring precision is difficult to guarantee.

Disclosure of Invention

Aiming at the defects, the invention provides a material flow metering detection method and a material flow metering detection system. The specific contents are as follows:

a method of flow metering detection comprising: projecting line laser to the material to be detected on the conveyor belt; a binocular camera is used for shooting a material image with line laser to obtain a material instant profile laser line; obtaining real-time contour laser line three-dimensional data by using a line laser binocular measurement method; the conveyor belt moves at a constant speed, and real-time profile laser line three-dimensional data are obtained by using a line laser binocular measurement method to obtain a three-dimensional data set so as to form point cloud data; determining a data boundary according to the point cloud data, dividing the point cloud data into micro areas based on an XOY plane, uniformly sampling, and recording three-dimensional coordinates of sampling points; calculating the volume of the sampling cuboid by taking the area of the micro region as the bottom area and the Z value of the sampling point as the height; and summing the volumes of the sampling cuboids to obtain the volume of the material passing through the line laser scanning part.

Further, the line laser binocular measuring method comprises the following steps: carrying out three-dimensional calibration on the binocular camera; respectively acquiring a left material image and a right material image of the laser with lines through a left camera and a right camera of a binocular camera; performing stereo correction on the acquired left image and right image to align the corrected left image and right image; matching the corrected left image and the corrected right image to obtain a linear laser imaging matching point pair; and obtaining left and right image parallax according to the line laser imaging matching point pairs, and calculating three-dimensional material contour data at the laser line projection position according to the left and right image parallax.

The invention also includes a system for measuring and detecting the flow of a material, comprising: the system comprises a conveyor belt, a line laser emitter, a binocular camera and a data processing module. Wherein:

the conveyor belt moves at a constant speed, and conveyed materials are metered by the material flow metering and detecting system;

the line laser emitter projects line laser to the conveyor belt and materials on the conveyor belt so as to obtain instant profile laser lines of the materials;

the method comprises the following steps that a binocular camera acquires a left material image and a right material image of a strip line laser, and parameters of a left camera and parameters of a right camera of the binocular camera are the same;

the data processing module analyzes and processes the left image and the right image of the material with the laser to obtain three-dimensional data of the material profile at the laser line projection position;

the line laser emitter projects line laser perpendicular to the conveying plane of the conveyor belt.

The invention has the beneficial effects that: the method and the system for detecting the material flow measurement can stably and reliably acquire three-dimensional data at the position of material flow profile laser line scanning; sampling and integral calculation are utilized, and the calculation error of the material flow volume is reduced; the measurement is carried out in real time along with the running state of the conveyor belt, and the real-time performance is good; the equipment is convenient to install, simple and easy to use, and wide in applicability.

Drawings

Fig. 1 is a schematic view of a material flow measurement detection method and system according to the present invention.

In the figure: 1. a conveyor belt; 2. a line laser transmitter; 3. a binocular camera; 4. a stream; 5. a flow profile laser line.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.

The invention aims to solve the technical problem that in the actual production at present, a weighing and metering method is usually adopted for metering granular or powdery solid materials, an electronic belt scale is often used for measuring in the material conveying process by adopting the weighing sensor principle, and signals of the weighing sensor are easily interfered when a belt runs, so that the measurement precision is difficult to ensure.

Aiming at the defect, the invention provides a material flow measurement detection method and a material flow measurement detection system, wherein a binocular line-adding laser detection method is adopted, three-dimensional data of a material flow profile on a conveyor belt is acquired, integration is carried out by utilizing the three-dimensional data to obtain the material flow volume, the material flow profile can be quickly and accurately acquired by utilizing line laser, the profile data and the integration calculation are calculated by combining a binocular stereo vision principle, the volume of the material flow can be quickly and accurately acquired, and the calculation of the material flow is completed.

Referring to fig. 1, the embodiment of the present invention specifically includes the following steps:

(1) and carrying out three-dimensional calibration on the binocular camera. The method specifically comprises the following steps:

respectively calibrating a left camera and a right camera of a binocular camera to obtain an internal reference matrix A of the binocular camera and a rotation matrix R of the left camera₁And a rotation matrix R of the right camera₂And the translation vector T of the left camera₁And a translation vector T of the right camera₂；

Calculating a rotation matrix R and a translation vector T between the left camera and the right camera according to the following formula:

(2) and opening the line laser transmitter, and controlling the line laser emitted by the line laser transmitter to project on the material to be detected on the conveyor belt.

(3) And respectively acquiring a left material image and a right material image of the laser with the line through a left camera and a right camera of the binocular camera.

(4) And performing stereo correction on the acquired left image and right image to align the corrected left image and right image. Performing stereo correction includes:

decomposing the rotation matrix R into two rotation matrices R₁And r₂Wherein r is₁And r₂The method comprises the steps that the left camera and the right camera are rotated by half respectively to enable the optical axes of the left camera and the right camera to be parallel;

aligning the left image and the right image is achieved by:

wherein R is_rectRotation matrix to align rows:

rotation matrix R_rectBy pole e₁Starting the direction, mainly using the original point of the left image, and taking the direction from the left camera to the translation vector of the right camera as a main point direction:

e₁and e₂Is orthogonal to e₁Normalized to unit vector:

wherein, T_xIs the component of the translation vector T in the horizontal direction in the plane of the binocular camera, T_yThe component of the translation vector T in the vertical direction in the plane where the binocular camera is located is taken as the translation vector T;

e₃and e₁And e₂Orthogonal, e₃Calculated by the following formula:

e₃＝e₂×e₁

according to the physical significance of the rotation matrix, the method comprises the following steps:

wherein alpha is the angle of the left camera and the right camera which need to rotate in the plane where the left camera and the right camera are located, and alpha is more than or equal to 0 and less than or equal to 180 degrees; for the left camera, make it wind e₃Direction rotation α', for the right camera, around e₃The direction is rotated by a ".

(5) And matching the corrected left image and the right image to obtain a line laser imaging matching point pair. The method specifically comprises the following steps:

determining a processing region ROI of the image according to the detection system and the position of the material flow to be detected;

preprocessing the corrected left image and the corrected right image, and respectively converting the preprocessed left image and the corrected right image into a left gray image and a right gray image;

respectively carrying out horizontal scanning on the parts of the left gray-scale image and the right gray-scale image, which are positioned in the ROI, and calculating the window energy of each scanning point:

wherein, (x, y) represents the scanning point coordinate, and is also the center coordinate of the calculation window; n represents the distance from the center to the edge of the selected window of the left gray map, and I (x + I, y + j) represents the gray value of the image at the image coordinates (x + I, y + j);

the maximum value of each scanning line E (x, y) is the imaging position of the line laser, M extreme values are obtained according to the number M of the line lasers, and the extreme values are sorted from left to right according to the x coordinate and are marked as (x, y)_k，k＝1，2，...M；

Scanning a horizontal polar line formed by horizontal scanning lines with the same coordinates y of the left gray-scale image and the right gray-scale image to obtain line laser imaging points (x) of the left gray-scale image and the right gray-scale image_L，y)_kAnd (x)_R，y)_kL and R denote a left gray map and a right gray map, respectively, and points where k is the same in the left and right sequences constitute a matching point pair.

(6) And obtaining left and right image parallax according to the line laser imaging matching point pairs, and calculating three-dimensional material contour data at the laser line projection position according to the left and right image parallax. The method specifically comprises the following steps:

the parallax of the line laser imaging on the horizontal polar line of the y-th line is calculated by the following formula:

d_yk＝x_L-x_R，k＝1，2，...M，

wherein d is_ykThe parallax of the k-th laser imaging point of the polar line with the ordinate of y;

and (3) calculating three-dimensional coordinates (Z, X, Y) of each point of the material outline at the laser line projection position in the space according to an internal reference matrix A and an external reference matrix [ R T ] of the binocular camera and the following formula:

where f is the extrinsic parameter matrix [ R T]The focal length of the middle binocular camera, B is the distance between the left camera and the right camera in the internal reference matrix A, and is given by calibration information; x_L-X_RDisparity between the left gray scale image and the right gray scale image for a point in space is given by matching information; (x, y) is the coordinate of the material contour point where the laser line is projected on the imaging plane.

(7) Keeping the conveyor belt moving at a constant speed, scanning materials on the conveyor belt by line laser, and sequentially shooting a left image and a right image of each instant profile laser line by a binocular camera.

(8) And (5) repeating the steps (4) to (7) to obtain the three-dimensional data of each instant profile laser line, and obtaining a three-dimensional data set to form point cloud data.

(9) And determining a data boundary according to the point cloud data, dividing the point cloud data into micro areas based on an XOY plane, uniformly sampling, and recording three-dimensional coordinates of sampling points. The method specifically comprises the following steps:

and determining a maximum data boundary according to the point cloud data, uniformly sampling the point cloud data in the boundary region based on an XOY plane, wherein a sampling interval delta D is a x D, D is the maximum boundary length, and taking a point closest to the center of the sampling region in the sampling region as a sampling point. Where a is a constant less than 1 and the smaller a, the smaller the sampling interval, the smaller the sampling area, and the more accurate the calculation of the volume of the stream.

(10) And calculating the volume of the sampling cuboid by taking the area of the micro region as the bottom area and the Z value of the sampling point as the height. The specific calculation method is as follows: v_n＝(Δd)²*Z_nIn which V is_nIs the volume of any sampling cuboid, and Zn is the height of the sampling cuboid.

(11) And summing the volumes of the sampling cuboids to obtain the volume of the material passing through the line laser scanning part. Namely:

the above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention with equivalent substitutions, changes, material substitutions, improvements, etc. within the technical scope of the present invention.