Hot-rolled coil speed measuring method combining linear-area array camera
阅读说明：本技术 一种线面阵相机相结合的热轧卷测速方法 (Hot-rolled coil speed measuring method combining linear-area array camera ) 是由 杨朝霖 邓能辉 徐科 周鹏 于 2020-04-24 设计创作，主要内容包括：本发明提供一种线面阵相机相结合的热轧卷测速方法,能够降低对面阵相机采集帧速率的要求。所述方法包括：通过测速标定确定线阵相机的固定采集线速率；触发线面阵相机同时采集待测速的热轧卷图像,利用线阵相机在不同运动速度下使用同一固定采集线速率会造成图像变形的特点,将面阵相机采集的单张图像和线阵相机采集的图像进行对比,根据采集的图像中变化区域的变形情况,确定热轧卷的实际运动速度；其中,线面阵相机包括：面阵相机和线阵相机,线面阵相机都位于热轧钢板的正上方,且线面阵相机位于同一高度同一水平位置。本发明涉及机器视觉应用技术领域。(The invention provides a hot-rolled coil speed measuring method combining a linear-area-array camera, which can reduce the requirement on the acquisition frame rate of the linear-area-array camera. The method comprises the following steps: determining the fixed acquisition linear velocity of the linear array camera through speed measurement calibration; triggering a linear-area camera to simultaneously acquire images of a hot rolled coil to be measured, comparing a single image acquired by the linear-area camera with an image acquired by the linear-area camera by utilizing the characteristic that the linear-area camera can cause image deformation by using the same fixed acquisition linear velocity at different movement speeds, and determining the actual movement speed of the hot rolled coil according to the deformation condition of a change area in the acquired image; wherein, line area array camera includes: the hot-rolled steel plate hot-rolling device comprises an area-array camera and a linear array camera, wherein the linear array camera is positioned right above the hot-rolled steel plate, and the linear array camera is positioned at the same height and the same horizontal position. The invention relates to the technical field of machine vision application.)
1. A hot rolled coil speed measurement method combining a linear-area array camera is characterized by comprising the following steps:
determining the fixed acquisition linear velocity of the linear array camera through speed measurement calibration;
triggering a linear-area camera to simultaneously acquire images of a hot rolled coil to be measured, comparing a single image acquired by the linear-area camera with an image acquired by the linear-area camera by utilizing the characteristic that the linear-area camera can cause image deformation by using the same fixed acquisition linear velocity at different movement speeds, and determining the actual movement speed of the hot rolled coil according to the deformation condition of a change area in the acquired image;
wherein, line area array camera includes: the hot-rolled steel plate hot-rolling device comprises an area-array camera and a linear array camera, wherein the linear array camera is positioned right above the hot-rolled steel plate, and the linear array camera is positioned at the same height and the same horizontal position.
2. The method for measuring the speed of a hot rolled coil by combining a linear-area-array camera with a linear-area-array camera according to claim 1, wherein the acquisition area of the area-array camera is M1×N1Wherein M is1Represents the acquisition range of the area-array camera in the width direction of the steel plate, N1Representing the acquisition range of the area-array camera in the length direction of the steel plate;
the resolution of the photosensitive device of the area-array camera is W1×L1；
Accuracy α of area-array camera in steel plate width direction1＝M1/W1；
Precision sigma of area-array camera in length direction of steel plate1＝N1/L1；
Wherein, α1＝σ1。
3. The hot-rolled coil speed measuring method combining linear and planar array cameras as claimed in claim 1, wherein the accuracy of the linear array cameras in the width direction of the steel plate is α2＝M2/W2Wherein M is2Represents the acquisition range of the linear array camera in the width direction of the steel plate, W2Representing the resolution of a photosensitive device of the line camera;
wherein M is2>＝M1The position of the acquisition line is positioned in the acquisition range N of the area array camera in the length direction of the steel plate1And (4) the following steps.
4. The method for measuring the speed of the hot rolled coil by combining the linear-area array camera according to claim 1, wherein before the fixed acquisition linear rate of the linear-area array camera is determined by speed measurement calibration, the method further comprises the following steps:
determining a pixel position mapping relation between linear-area cameras in the width direction of the steel plate, wherein the determined pixel position mapping relation between the linear-area cameras is expressed as:
WP2＝(WP1×α1)/α2
wherein, WP1The pixel position of the area-array camera in the width direction of the steel plate, WP2α for the pixel position of the line camera in the width direction of the steel plate1α for the accuracy of the area-array camera in the width direction of the steel sheet2The accuracy of the linear array camera in the width direction of the steel plate is obtained.
5. The method for measuring the speed of the hot rolled coil by combining the linear-area array camera according to claim 1, wherein the step of determining the fixed acquisition linear rate of the linear-area array camera through speed measurement calibration comprises the following steps:
passing the hot-rolled coil through a speed measuring position at a constant speed according to a known calibration speed v, and sending external trigger signals with different frequencies to an area-array camera and a line at the same time by using a dual-path PWM signal generatorThe array camera carries out image acquisition, wherein within a calibrated acquisition time t, the two-way PWM signal generator sends 1 pulse square wave to the area array camera, the pulse square wave triggers the area array LED light source to carry out high-brightness illumination, the area array camera starts to acquire a single image of the hot rolled coil at the rising edge of the pulse square wave, and the linear array camera starts to acquire a single image of the hot rolled coil according to a fixed pulse frequency f sent by the two-way PWM signal generator at the same time1Collecting an image of a hot rolled coil;
determining the height L of an image acquired by a line-scan camera2And the precision sigma of the linear array camera in the length direction of the steel plate2The relationship between them is: sigma2＝N1/L2＝ν/f1Wherein N is1Denotes the acquisition range of the area-array camera in the longitudinal direction of the steel sheet, α2The accuracy of the linear array camera in the width direction of the steel plate is shown;
according to α2＝σ2For a fixed pulse frequency f1Correcting to obtain corrected fixed pulse frequency f2＝f1×(β1/β2) Wherein, β1Area of variation delta in acquired images for area-array camera1Pixel aspect ratio of β2Is Δ2Pixel aspect ratio of region, Δ2The area is a change area delta obtained according to the pixel position mapping relation between the linear area array cameras1The same acquisition region of the corresponding linear array camera;
will f is2As a fixed acquisition line rate for the line camera.
6. A method for measuring the speed of a hot rolled coil by combining a linear-area-array camera and a linear-area-array camera according to claim 5, characterized in that a group of area-array cameras equipped with narrow-band color filters, linear-array cameras and monochromatic area-array LED light sources are used.
7. The method for measuring the speed of the hot rolled coil combined by the linear-area array camera according to claim 5, wherein the triggering the linear-area array camera to simultaneously acquire images of the hot rolled coil to be measured, the characteristic that the linear-area array camera uses the same fixed acquisition linear velocity to cause image deformation under different movement speeds is utilized to compare a single image acquired by the linear-area array camera with an image acquired by the linear-area array camera, and the determining the actual movement speed of the hot rolled coil according to the deformation condition of a variation area in the acquired image comprises:
the hot rolled coil to be tested passes through a speed measuring position, and external trigger signals with different frequencies are sent to the area-array camera and the linear array camera at the same time by utilizing the double-path PWM signal generator to carry out image acquisition;
the method comprises the steps of comparing a single image acquired by an area-array camera with an image acquired by the line-array camera by utilizing the characteristic that the image deformation is caused by the same fixed acquisition linear velocity of the line-array camera at different motion speeds to acquire a change area delta in the image of a hot-rolled coil to be tested acquired by the area-array camera1Obtaining a corresponding area delta in the acquired image of the linear array camera according to the pixel position mapping relation between the linear array cameras2；
Determination of Delta1Pixel aspect ratio β of region1And delta2Pixel aspect ratio β of region2；
According to the determined delta1Pixel aspect ratio β of region1、Δ2Pixel aspect ratio β of region2And calibrating the speed v, and determining the actual movement speed of the hot-rolled coil.
8. The linear-area-array-camera-combined hot-rolled coil speed measurement method according to claim 7, wherein the determined actual moving speed of the hot-rolled coil is represented as:
ν1＝ν×(β1/β2)
wherein, v1Representing the actual movement speed of the hot rolled coil.
Technical Field
The invention relates to the technical field of machine vision application, in particular to a hot-rolled coil speed measuring method combining a linear-area array camera.
Background
In order to ensure accurate positioning of the position of the defect, the accurate speed of the hot rolled coil at the detection position needs to be obtained, the speed received from the production line level 1 or level 2 at present often cannot accurately correspond to the speed of the detection position, certain deviation can be caused, an independent speed measuring device needs to be installed, the cost of a laser speed measuring mode is high, a plurality of images need to be collected in a common single-sided array image speed measuring mode, the movement of an object is judged according to the change condition of a superposition area, the moving speed of the hot rolled strip steel is high and reaches about 15m/s, in order to ensure that the images have the superposition area, a very high collection frame rate is needed for an area array camera, the cost of the area array camera with the high collection frame rate can be much higher, and the excessively high collection frame rate can cause the exposure time of the camera to be too short, so that.
Disclosure of Invention
The invention aims to solve the technical problem of providing a hot-rolled coil speed measurement method combining a linear-area-array camera, so as to solve the problems that the prior art needs an area-array camera with a high acquisition frame rate, and the excessive acquisition frame rate causes image quality reduction and affects speed measurement precision.
In order to solve the technical problem, an embodiment of the present invention provides a hot rolled coil speed measurement method combining a linear-area array camera, including:
determining the fixed acquisition linear velocity of the linear array camera through speed measurement calibration;
triggering a linear-area camera to simultaneously acquire images of a hot rolled coil to be measured, comparing a single image acquired by the linear-area camera with an image acquired by the linear-area camera by utilizing the characteristic that the linear-area camera can cause image deformation by using the same fixed acquisition linear velocity at different movement speeds, and determining the actual movement speed of the hot rolled coil according to the deformation condition of a change area in the acquired image;
wherein, line area array camera includes: the hot-rolled steel plate hot-rolling device comprises an area-array camera and a linear array camera, wherein the linear array camera is positioned right above the hot-rolled steel plate, and the linear array camera is positioned at the same height and the same horizontal position.
Further, the acquisition area of the area-array camera is M1×N1Wherein M is1Represents the acquisition range of the area-array camera in the width direction of the steel plate, N1Representing the acquisition range of the area-array camera in the length direction of the steel plate;
the resolution of the photosensitive device of the area-array camera is W1×L1；
Accuracy α of area-array camera in steel plate width direction1＝M1/W1；
Precision sigma of area-array camera in length direction of steel plate1＝N1/L1；
Wherein, α1＝σ1。
Further, the accuracy α of the line camera in the width direction of the steel plate2＝M2/W2Wherein M is2Represents the acquisition range of the linear array camera in the width direction of the steel plate, W2Representing the resolution of a photosensitive device of the line camera;
wherein M is2>＝M1The position of the acquisition line is positioned in the acquisition range N of the area array camera in the length direction of the steel plate1And (4) the following steps.
Further, before determining the fixed acquisition linear velocity of the line camera through speed measurement calibration, the method further comprises:
determining a pixel position mapping relation between linear-area cameras in the width direction of the steel plate, wherein the determined pixel position mapping relation between the linear-area cameras is expressed as:
WP2＝(WP1×α1)/α2
wherein, WP1The pixel position of the area-array camera in the width direction of the steel plate, WP2α for the pixel position of the line camera in the width direction of the steel plate1α for the accuracy of the area-array camera in the width direction of the steel sheet2The accuracy of the linear array camera in the width direction of the steel plate is obtained.
Further, the determining the fixed acquisition linear velocity of the line camera through speed measurement calibration comprises:
the method comprises the steps of enabling a hot-rolled coil to pass through a speed measuring position at a constant speed according to a known calibration speed v, sending external trigger signals with different frequencies to an area-array camera and a linear array camera at the same time by utilizing a double-path PWM signal generator to carry out image acquisition, wherein within a calibrated acquisition time t, the double-path PWM signal generator sends 1 pulse square wave to the area-array camera, and the pulse square wave triggersThe area array LED light source performs high-brightness illumination, the area array camera starts to acquire images of the hot-rolled coil at the rising edge of the pulse square wave, and the linear array camera transmits a fixed pulse frequency f at the same time according to the double-path PWM signal generator1Collecting an image of a hot rolled coil;
determining the height L of an image acquired by a line-scan camera2And the precision sigma of the linear array camera in the length direction of the steel plate2The relationship between them is: sigma2＝N1/L2＝ν/f1Wherein N is1Denotes the acquisition range of the area-array camera in the longitudinal direction of the steel sheet, α2The accuracy of the linear array camera in the width direction of the steel plate is shown;
according to α2＝σ2For a fixed pulse frequency f1Correcting to obtain corrected fixed pulse frequency f2＝f1×(β1/β2) Wherein, β1Area of variation delta in acquired images for area-array camera1Pixel aspect ratio of β2Is Δ2Pixel aspect ratio of region, Δ2The area is a change area delta obtained according to the pixel position mapping relation between the linear area array cameras1The same acquisition region of the corresponding linear array camera;
will f is2As a fixed acquisition line rate for the line camera.
Further, a set of an area camera equipped with a narrow-band color filter, a line camera, and a monochromatic area-array LED light source is employed.
Further, triggering the linear-area camera to simultaneously acquire images of the hot rolled coil to be tested, comparing a single image acquired by the linear-area camera with an image acquired by the linear-area camera by using the characteristic that the same fixed acquisition linear velocity of the linear-area camera causes image deformation at different movement velocities, and determining the actual movement velocity of the hot rolled coil according to the deformation condition of a variation area in the acquired image comprises:
the hot rolled coil to be tested passes through a speed measuring position, and external trigger signals with different frequencies are sent to the area-array camera and the linear array camera at the same time by utilizing the double-path PWM signal generator to carry out image acquisition;
the method comprises the steps of comparing a single image acquired by an area-array camera with an image acquired by the line-array camera by utilizing the characteristic that the image deformation is caused by the same fixed acquisition linear velocity of the line-array camera at different motion speeds to acquire a change area delta in the image of a hot-rolled coil to be tested acquired by the area-array camera1Obtaining a corresponding area delta in the acquired image of the linear array camera according to the pixel position mapping relation between the linear array cameras2；
Determination of Delta1Pixel aspect ratio β of region1And delta2Pixel aspect ratio β of region2；
According to the determined delta1Pixel aspect ratio β of region1、Δ2Pixel aspect ratio β of region2And calibrating the speed v, and determining the actual movement speed of the hot-rolled coil.
Further, the determined actual moving speed of the hot rolled coil is expressed as:
ν1＝ν×(β1/β2)
wherein, v1Representing the actual movement speed of the hot rolled coil.
The technical scheme of the invention has the following beneficial effects:
in the scheme, the high acquisition linear rate of the linear array camera is utilized, the characteristics of simultaneous acquisition of the linear array camera and the area camera are combined, images acquired by the linear array camera and the area camera are overlapped inevitably, and the characteristics that the linear array camera uses the same fixed acquisition linear rate to cause image deformation under different movement speeds are utilized to compare and analyze a single image acquired by the area camera with the image acquired by the linear array camera, determining the actual moving speed of the hot-rolled coil according to the deformation condition of the change area in the acquired image, therefore, the actual movement speed of the hot-rolled coil can be accurately calculated only by using a single area-array camera image, the calculation of the speed can be completed under the condition that the front image and the rear image acquired at different moments are overlapped compared with the traditional area-array camera speed measurement, and the requirement on the acquisition frame rate of the area-array camera under the condition that the hot-rolled coil moves at a high speed is reduced.
Drawings
Fig. 1 is a schematic flow chart of a hot-rolled coil speed measurement method combining a linear-area-array camera according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a hardware structure involved in a hot-rolled coil speed measurement method provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram of a two-way PWM signal according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a variation area of a line-area array camera according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides a hot-rolled coil speed measurement method combining a linear-area-array camera, aiming at the problems that the prior area-array camera with high acquisition frame rate reduces image quality and affects speed measurement precision due to overhigh acquisition frame rate.
As shown in fig. 1, a method for measuring speed of a hot rolled coil by combining a linear-area-array camera provided in an embodiment of the present invention includes:
s101, determining a fixed acquisition linear velocity of the linear array camera through speed measurement calibration;
s102, triggering a linear-area camera to simultaneously acquire images of a hot rolled coil to be tested, comparing a single image acquired by the area camera with an image acquired by the linear-array camera by utilizing the characteristic that the linear-array camera can cause image deformation by using the same fixed acquisition linear velocity at different movement velocities, and determining the actual movement velocity of the hot rolled coil according to the deformation condition of a variation area in the acquired image;
wherein, line area array camera includes: the hot-rolled steel plate hot-rolling device comprises an area-array camera and a linear array camera, wherein the linear array camera is positioned right above the hot-rolled steel plate, and the linear array camera is positioned at the same height and the same horizontal position.
The hot rolling roll speed measurement method combining the linear-array camera and the area-array camera in the embodiment of the invention utilizes the high linear acquisition rate of the linear-array camera and combines the characteristics of the linear-array camera and the area-array camera for simultaneous acquisition, images acquired by the linear-array camera and the area-array camera are overlapped inevitably, and utilizes the characteristic that the linear-array camera uses the same fixed linear acquisition rate to cause image deformation under different movement speeds to compare and analyze a single image acquired by the area-array camera with the image acquired by the linear-array camera, determining the actual moving speed of the hot-rolled coil according to the deformation condition of the change area in the acquired image, therefore, the actual movement speed of the hot-rolled coil can be accurately calculated only by using a single area-array camera image, the calculation of the speed can be completed under the condition that the front image and the rear image acquired at different moments are overlapped compared with the traditional area-array camera speed measurement, and the requirement on the acquisition frame rate of the area-array camera under the condition that the hot-rolled coil moves at a high speed is reduced.
The embodiment of the invention provides a hot-rolled coil speed measurement method combining a linear-area array camera, and relates to equipment comprising the following steps: 1 line camera, 1 area camera, an area LED (Light Emitting Diode) Light source and a dual channel PWM (Pulse Width Modulation) signal generator, as shown in fig. 2.
In the foregoing specific embodiment of the method for measuring speed of hot rolled coil by combining linear-area-array cameras, further, the acquisition area of the area-array camera is M1×N1Wherein M is1Represents the acquisition range of the area-array camera in the width direction of the steel plate, N1Representing the acquisition range of the area-array camera in the length direction of the steel plate;
the resolution of the photosensitive device of the area-array camera is W1×L1；
Accuracy α of area-array camera in steel plate width direction1＝M1/W1；
Precision sigma of area-array camera in length direction of steel plate1＝N1/L1；
Wherein, α1＝σ1。
As shown in fig. 2, before speed measurement, an area-array camera and a line-array camera need to be installed right above a hot rolled steel plate, and the line-array cameras are located at the same height and the same horizontal position, so that an acquisition area which can be realized by the area-array camera is M1×N1，M1、N1Using millimeters (mm) as a unit; photosensitive device for area-array cameraThe resolution of the piece may use pixels (piexl) as a unit.
In the foregoing specific embodiment of the method for measuring speed of hot rolled coil by combining linear-area cameras, further, the accuracy α of the linear-area cameras in the width direction of the steel plate2＝M2/W2Wherein M is2Represents the acquisition range of the linear array camera in the width direction of the steel plate, W2Representing the resolution of a photosensitive device of the line camera;
wherein M is2>＝M1The position of the acquisition line (the shooting view of the linear array camera is a slender strip line) is positioned in the acquisition range N of the area array camera in the length direction of the steel plate1And (4) the following steps.
In this embodiment, the line camera and the area camera are installed at the same height and the same horizontal position, and are located right above the hot rolled steel sheet, and the acquisition range M of the line camera in the width direction of the steel sheet2Resolution W of linear array camera photosensitive device in millimeter (mm) unit2In units of pixels (piexl).
In this example, M2>＝M1The linear array camera can cover the acquisition area of the area array camera in the width direction of the steel coil, the acquisition environment is ensured to be consistent as much as possible, and the position image contrast possibility is provided.
In a specific embodiment of the foregoing method for measuring speed of a hot rolled coil by combining a linear-area array camera, further, before determining a fixed acquisition linear velocity of the linear-area array camera through speed measurement calibration, the method further includes:
determining a pixel position mapping relation between linear-area cameras in the width direction of the steel plate, wherein the determined pixel position mapping relation between the linear-area cameras is expressed as:
WP2＝(WP1×α1)/α2
wherein, WP1The pixel position of the area-array camera in the width direction of the steel plate, WP2α for the pixel position of the line camera in the width direction of the steel plate1α for the accuracy of the area-array camera in the width direction of the steel sheet2The accuracy of the linear array camera in the width direction of the steel plate is obtained.
In this embodiment, the determining the fixed acquisition linear velocity of the line scan camera through speed measurement calibration may specifically include the following steps:
a1, passing a hot-rolled coil through a speed measurement position at a constant speed according to a known calibration speed v, sending external trigger signals with different frequencies to an area-array camera and a linear array camera at the same time by using a double-path PWM signal generator for image acquisition, wherein within a calibrated acquisition time t, the double-path PWM signal generator sends 1 pulse square wave to the area-array camera, the pulse square wave triggers an area-array LED light source for high-brightness illumination, the area-array camera starts to acquire a single image of the hot-rolled coil at the rising edge of the pulse square wave, and the linear array camera sends a fixed pulse frequency f at the same time according to the double-path PWM signal generator1Acquiring an image of a hot rolled coil, as shown in FIG. 3; the calibrated acquisition time t and the calibrated speed v have the following relationship:
t＝N1/ν
a2, determining the height L of the image collected by the line camera2And the precision sigma of the linear array camera in the length direction of the steel plate2The relationship between them is: sigma2＝N1/L2＝ν/f1Wherein L is2＝f1×t＝f1×N1/ν，N1Denotes the acquisition range of the area-array camera in the longitudinal direction of the steel sheet, α2The accuracy of the linear array camera in the width direction of the steel plate is shown;
a3, according to α2＝σ2For a fixed pulse frequency f1Correcting to obtain corrected fixed pulse frequency f2＝f1×(β1/β2) Wherein, β1Area of variation delta in acquired images for area-array camera1Pixel aspect ratio of β2Is Δ2Pixel aspect ratio of region, Δ2The area is a change area delta obtained according to the pixel position mapping relation between the linear area array cameras1The same acquisition region of the corresponding linear array camera;
a4, mixing f2As a fixed acquisition line rate for the line camera.
In this embodiment, in step a3, a single image acquired by the area-array camera may be compared with an image acquired by the line-array camera by using the characteristic that the same fixed acquisition linear velocity of the line-array camera may cause image deformation at different motion speeds, so as to obtain a variation area Δ in the image acquired by the area-array camera1Then, according to the pixel position mapping relation between the linear-area cameras, obtaining the same acquisition region delta of the corresponding linear-area cameras2，Δ1And Δ2Corresponding to the same physical area and therefore having the same size, considering that the area-array camera has the same acquisition area precision, namely α1＝σ1Let a1The pixel aspect ratio of the region is β1＝h1/w1，Δ2The pixel aspect ratio of the region is β2＝h2/w2α, the requirement for ensuring equal precision of linear array camera acquisition regions2＝σ2For a fixed pulse frequency f1Correcting to obtain corrected fixed pulse frequency f2＝f1×(β1/β2) As shown in fig. 4.
In this embodiment, the speed measurement calibration work is completed at a certain known calibration speed v according to the steps a1-a4, and a suitable fixed acquisition linear velocity of the line camera is determined.
In the specific implementation mode of the hot-rolled coil speed measuring method combining the linear-area array camera, a group of area array cameras provided with narrow-band color filters, linear-area cameras and monochromatic area array LED light sources are further adopted.
In the embodiment, the monochromatic area array LED light source is combined with the narrow-band color filter to filter the interference of hot-rolled red background light.
In a specific implementation manner of the aforementioned hot rolled coil speed measurement method combining linear-area-array cameras, further, triggering the linear-area-array camera to simultaneously acquire images of a hot rolled coil to be speed measured, comparing a single image acquired by the area-array camera with an image acquired by the linear-array camera by using a characteristic that the same fixed acquisition linear velocity of the linear-array camera causes image deformation at different motion speeds, and determining an actual motion speed of the hot rolled coil according to a deformation condition of a variation area in the acquired image includes:
the hot rolled coil to be tested passes through a speed measuring position, and external trigger signals with different frequencies are sent to the area-array camera and the linear array camera at the same time by utilizing the double-path PWM signal generator to carry out image acquisition;
the method comprises the steps of comparing a single image acquired by an area-array camera with an image acquired by the line-array camera by utilizing the characteristic that the image deformation is caused by the same fixed acquisition linear velocity of the line-array camera at different motion speeds to acquire a change area delta in the image of a hot-rolled coil to be tested acquired by the area-array camera1Obtaining a corresponding area delta in the acquired image of the linear array camera according to the pixel position mapping relation between the linear array cameras2；
Determination of Delta1Pixel aspect ratio β of region1And delta2Pixel aspect ratio β of region2；
According to the determined delta1Pixel aspect ratio β of region1、Δ2Pixel aspect ratio β of region2And calibrating the speed v, and determining the actual movement speed of the hot-rolled coil.
In this embodiment, in the linear array camera, under the condition that the acquisition linear velocity is fixed, the characteristic that the image region is stretched and deformed when the object velocity changes is still present, an image may still be acquired by using the area-array camera, a region with changed image content is searched, and the length-width ratio of pixels in the region is obtained β1Aspect ratio β of pixels corresponding to the same region of the line camera acquired image2Then according to β1、β2And calibrating the speed v, and determining the actual movement speed of the hot-rolled coil, namely calculating the actual movement speed of the hot-rolled coil by analyzing the deformation degree of the images of the same region acquired by the area-array camera and the linear-array camera.
In the foregoing embodiment of the method for measuring speed of hot-rolled coil by combining linear-area-array cameras, further, the determined actual moving speed of the hot-rolled coil is represented as:
ν1＝ν×(β1/β2)
wherein, v1To representActual speed of movement of the hot rolled coil.
In this embodiment, the hot rolled coil does not have a backward movement, and therefore, it is not necessary to consider the forward and backward conditions of the speed.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
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