CN114509004A - Measuring method and measuring device based on machine vision - Google Patents
Measuring method and measuring device based on machine vision Download PDFInfo
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- CN114509004A CN114509004A CN202210179367.9A CN202210179367A CN114509004A CN 114509004 A CN114509004 A CN 114509004A CN 202210179367 A CN202210179367 A CN 202210179367A CN 114509004 A CN114509004 A CN 114509004A
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- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G—PHYSICS
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- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
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- G—PHYSICS
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- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
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Abstract
The invention belongs to the technical field of machine vision, and particularly relates to a measuring method and a measuring device based on machine vision, wherein the device comprises a marking mechanism, a measuring trigger unit, a processing unit, a fast reflection mirror, an imaging system, a spectroscope and a distance measuring unit; the processing unit is respectively and electrically connected with the measurement trigger unit, the imaging system and the distance measuring unit; the marking mechanism is used for marking two marking points with fixed distance on the surface to be detected of the workpiece; the conveyor belt is preset with a measuring section; the fast reflection mirror is positioned in the measuring section and used for reflecting the detection surface image of the workpiece in the measuring section to the spectroscope; the distance measuring unit is positioned on one side of the reflected light of the spectroscope, and the imaging system is positioned on one side of the transmitted light of the spectroscope; and the reflection distance from the light spot on the surface of the spectroscope to the ranging unit is equal to the transmission distance from the light spot to the imaging system. The dynamic measurement of the workpiece surface to be measured can be stably realized.
Description
Technical Field
The invention belongs to the technical field of machine vision, and particularly relates to a measuring method and a measuring device based on machine vision.
Background
With the development of machine vision technology, machine vision measurement and detection have been widely used in industrial fields. When the dimension of the surface to be detected of the workpiece is measured, in order to ensure the measurement accuracy, the shooting direction of the camera is required to be perpendicular to the surface to be detected of the workpiece, and the surface to be detected is approximately static in an imaging picture.
If the workpiece is to be measured in the working process of the conveyor belt, the camera is required to continuously rotate to shoot the workpiece in the conveying process of the workpiece, so that the position of the workpiece in an imaging picture is relatively fixed, and the dimension measurement is carried out in the shooting direction of the camera and is vertical to the surface to be measured of the workpiece. However, the dynamic performance of the camera is poor, the rotation flexibility is poor, the inertia is large due to the large weight, the above process is very difficult to realize, and the stability is difficult to ensure.
Therefore, when the surface to be detected of the workpiece is measured at present, an independent detection station is arranged, the camera and the workpiece to be detected are kept relatively static during detection, and the shooting surface of the camera is perpendicular to the surface to be detected of the workpiece. However, such a detection method requires a special detection link, and is very inefficient.
Disclosure of Invention
The invention aims to provide a measuring device based on machine vision, which can improve the measuring efficiency of a surface to be measured of a workpiece.
The basic scheme provided by the invention is as follows:
a measuring device based on machine vision comprises a marking mechanism, a measuring trigger unit, a processing unit, a fast reflecting mirror, an imaging system, a spectroscope and a distance measuring unit; the processing unit is respectively and electrically connected with the measurement trigger unit, the imaging system and the distance measuring unit;
the marking mechanism is used for marking two marking points with fixed distance on the surface to be detected of the workpiece; the conveyor belt is preset with a measuring section; the fast reflection mirror is positioned in the measuring section and used for reflecting the detection surface image of the workpiece in the measuring section to the spectroscope; the distance measuring unit is positioned on one side of the reflected light of the spectroscope, and the imaging system is positioned on one side of the transmitted light of the spectroscope; the reflection distance from the light spot on the surface of the spectroscope to the ranging unit is equal to the transmission distance from the light spot to the imaging system;
the measuring trigger unit is arranged at the starting position of the measuring section of the conveyor belt and used for sending a starting signal to the processing unit when a workpiece on the conveyor belt is detected; the processing unit is used for controlling the fast reflecting mirror to rotate after receiving the starting signal, so that the fast reflecting mirror reflects the image of the surface to be measured of the workpiece to the spectroscope, transmits the image to the imaging system after being transmitted by the spectroscope, and transmits the image to the distance measuring unit after being reflected by the spectroscope;
the processing unit is also used for analyzing the midpoint of the connecting line of the two marking points on the image of the imaging system and recording the midpoint as the target midpoint; the processing unit is also used for analyzing a deviation value between a target center point and a reference point preset on imaging by combining the detection data of the ranging unit, and driving the fast reflecting mirror to rotate according to the deviation value so that the deviation value continuously approaches to zero; the processing unit also prestores the actual distance between the two marking points; the processing unit is also used for analyzing the real-time distance between two mark points on the imaging according to the detection data of the imaging and ranging unit of the imaging system, and is also used for measuring and calculating the surface to be measured of the workpiece according to the imaging at the moment and the detection data of the ranging unit at the moment when the real-time distance is equal to the actual distance.
Basic scheme theory of operation and beneficial effect:
because when directly measuring the face of awaiting measuring of the work piece in the transmission course on the conveyer belt, the dynamic property of camera can not satisfy the user demand, and the present technical improvement thinking of technical staff in the field improves camera itself and the actuating mechanism of camera to promote the dynamic property of camera. Because dynamic measurement can be realized as long as the dynamic performance of the camera is improved to the extent of meeting the requirements. But the current schedule is not ideal and very costly. The applicant breaks away from the thinking inertia, is not limited to the dynamic performance of the camera, changes a technical idea, starts with the scheme design from the picture received by the camera, does not need to move the camera, and realizes dynamic measurement in a simple and low-cost mode.
By using the device, a workpiece to be detected is marked with two mark points with fixed distance by a marking mechanism, and the workpiece is positioned on the conveying belt, and the surface to be detected faces the quick reflection mirror. When the workpiece is transferred to the start position of the measuring section, the measurement triggering unit detects the workpiece and sends a start signal to the processing unit. And the processing unit receives the starting signal and then controls the fast reflecting mirror to rotate, so that the fast reflecting mirror reflects the image of the surface to be measured of the workpiece to the spectroscope, and the image is transmitted to the imaging system for imaging after being transmitted by the spectroscope. Meanwhile, the image reflected by the spectroscope is sent to the distance measuring unit. Since the reflection distance of the spot on the surface of the beam splitter to the ranging unit is equal to the transmission distance of the spot to the imaging system. Through the detection data of the imaging and ranging unit, the processing unit can calculate the distance between two mark points on the imaging.
Then, the processing unit analyzes the midpoint of the connecting line of the two marking points on the image of the imaging system and records the midpoint as the target midpoint; and calculating a deviation value between the target midpoint and a reference point preset on imaging by combining the detection data of the ranging unit, and driving the fast reflecting mirror to rotate according to the deviation value so that the deviation value continuously approaches to zero. Equivalently, the position of the midpoint of the target on the imaging approaches to be static, so that the effect that the surface to be measured of the workpiece is approximately static on the imaging is achieved. In the above process, the processing unit may further continuously analyze the real-time distance between the two mark points on the image, and when the real-time distance is equal to the actual distance, it is described that the size of the surface to be measured in the image is exactly the same as the size of the actual surface to be measured (in other words, the surface to be measured is exactly perpendicular to the shooting angle of the imaging system at this time, and the image is not distorted).
This application realizes dynamic measurement through controlling the quick reflection mirror, and the quick reflection mirror is compared with the camera, and its dynamic behavior is very outstanding, its turned angle of control that can be very accurate and light. Besides, the factor driving the fast reflecting mirror to rotate is the deviation value of a target midpoint and a reference point on the image, the image is obtained after the fast reflecting mirror is reflected to an imaging system, and the reflection angle is equal to the incident angle, so that the fast reflecting mirror can complete the tracking of the surface to be measured of the workpiece only by rotating half of the angle compared with the direct rotating camera, the tracking efficiency is more efficient, and the control precision can be further ensured because the angular speed equivalent to the rotation is changed into half by rotating half of the angle. The imaging system does not need to rotate, and only needs to select the model with proper shooting capability, so that the cost can be effectively controlled.
To sum up, use this device, only need increase less cost, alright with the dynamic measurement of stable realization work piece face that awaits measuring, compare with artifical the detection, need not set up special static measurement link and station, can promote the measurement of work piece face that awaits measuring efficiency.
Further, the fast reflecting mirror is a single-axis fast reflecting mirror; the processing unit drives the fast reflecting mirror to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value of the X axis continuously approaches to zero; wherein, the positive direction of X axle is the direction of transfer of conveyer belt.
Has the advantages that: in the conveying process of the conveyor belt, the workpiece and the conveyor belt are relatively static and do not move in the width direction (namely the Y-axis direction) of the conveyor belt, so that the deviation value of the target midpoint and the reference point on the Y axis is stable originally, and even if the shooting angle changes, the change of the deviation value of the Y axis is very slow. Therefore, the aim that the position of the target midpoint on the imaging is close to static can be achieved only by tracking the X axis of the target midpoint. In addition, the driving of the fast reflecting mirror can be more concise and stable through the mode, and therefore the overall stability of dynamic detection is further improved.
Further, the device also comprises an ending triggering unit and an alarm unit which are respectively electrically connected with the processing unit; the end triggering unit is arranged at the end position of the measuring section of the conveyor belt and used for sending an end signal to the processing unit when the workpiece on the conveyor belt is detected; the processing unit is also used for controlling the alarm unit to give an alarm when the end signal is received but the surface to be measured of the corresponding workpiece is not measured.
Has the advantages that: if the workpiece reaches the end of the measuring section and the surface to be measured of the corresponding workpiece is not measured, the situation that the shooting angle is perpendicular to the surface to be measured does not occur in the whole measuring section, and the workpiece is placed in a problem. Therefore, an alarm is given, so that the working personnel can know the situation and measure the surface to be measured of the workpiece independently.
Further, the measurement trigger unit and the ending trigger unit are both photoelectric switch sensors.
Has the advantages that: the cost is lower, simple to operate and stable performance.
Further, the reference point is a center point of the imaging.
Has the advantages that: compare in other positions with setting up the reference point, can guarantee that the face of awaiting measuring of work piece is in the region that is close to the centre position all the time, chooses for use the camera of big image plane, little visual field can satisfy the demand, like this, can promote the formation of image resolution ratio, further guarantees measuring result's accuracy.
Further, the processing unit stores the initial angle of the fast reflecting mirror; the processing unit is also used for controlling the quick reflection mirror to recover to the initial angle after measuring the surface to be measured of the workpiece.
Has the advantages that: when the worker places the workpiece, the worker usually places the workpiece at a position close to the middle (the position corresponding to the Y axis is relatively fixed), and when the dynamic measurement is started, the workpiece is at the starting position of the measurement section (the position corresponding to the X axis is relatively fixed). In conclusion, after the dynamic measurement is started, the position of the workpiece on the conveyor belt is relatively fixed, and the fast reflecting mirror can accurately track the surface to be measured of the workpiece as early as possible by reasonably setting the initial angle of the fast reflecting mirror.
The invention also provides a measuring method based on machine vision, which uses the measuring device based on machine vision and comprises the following steps:
s1, marking two mark points with fixed distance on the surface to be detected of the workpiece by a marking mechanism, and enabling the surface to be detected of the workpiece to face the quick reflection mirror;
s2, after the workpiece is detected to reach the measuring section, the measuring trigger unit sends a starting signal to the processing unit; the processing unit receives the starting signal and then controls the fast reflecting mirror to rotate, so that the fast reflecting mirror reflects the image of the surface to be measured of the workpiece to the spectroscope, transmits the image to the imaging system after being transmitted by the spectroscope, and transmits the image to the distance measuring unit after being reflected by the spectroscope;
s3, the processing unit analyzes the midpoint of the connecting line of the two marking points on the image of the imaging system and marks the midpoint as a target midpoint, analyzes the deviation value between the target midpoint and a reference point preset on the image, and drives the fast reflection mirror to rotate according to the deviation value so that the deviation value continuously approaches to zero;
and S4, the processing unit analyzes the real-time distance between two marking points on the imaging according to the detection data of the imaging and ranging unit of the imaging system, and when the real-time distance is equal to the pre-stored actual distance, the processing unit measures and calculates the surface to be measured of the workpiece according to the imaging at the moment and the detection data of the ranging unit at the moment.
Has the advantages that: by using the method, the dynamic measurement of the surface to be measured of the workpiece can be stably realized only by increasing less cost, and compared with manual detection, the method does not need to set a special static measurement link and station, and can improve the measurement efficiency of the surface to be measured of the workpiece.
Further, in S3, the processing unit drives the fast-reflection mirror to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value of the X axis continuously approaches to zero; wherein, the positive direction of X axle is the direction of transfer of conveyer belt.
Has the advantages that: by the mode, the driving of the fast reflecting mirror can be more concise and stable, and the overall stability of dynamic detection is further improved.
Further, S5, when the workpiece on the conveyor belt is detected, the end trigger unit is set to send an end signal to the processing unit; and if the surface to be measured of the corresponding workpiece is not measured when the end signal is received, the processing unit controls the alarm unit to give an alarm.
Has the advantages that: if the workpiece reaches the end of the measuring section and the surface to be measured of the corresponding workpiece is not measured, the situation that the shooting angle is vertical to the surface to be measured does not occur in the whole measuring section, and therefore an alarm is given out to enable workers to know the situation.
Further, in S3, the reference point is the center point of the image.
Has the advantages that: like this, can choose for use the camera of big image plane, little visual field can satisfy the demand, like this, can promote the formation of image resolution ratio, further guarantee measuring result's accuracy.
Drawings
FIG. 1 is a schematic diagram of a first embodiment of the present invention;
fig. 2 is a logic block diagram of a first embodiment of the invention.
Detailed Description
The following is further detailed by the specific embodiments:
reference numerals in the drawings of the specification include: the device comprises a measurement trigger unit 1, an end trigger unit 2, a workpiece 3, a fast reflecting mirror 4, a spectroscope 5, an imaging system 6, a distance measuring unit 7 and a processing unit 8.
Example one
Because when directly measuring the face to be measured of work piece 3 in the transmission course on the conveyer belt, the dynamic property of camera can not satisfy the user demand, and the present technical improvement thinking of technical staff in the field improves camera itself and the actuating mechanism of camera to promote the dynamic property of camera. Because dynamic measurement can be realized as long as the dynamic performance of the camera is improved to the extent of meeting the requirements. But the current schedule is not ideal and very costly.
The applicant breaks away from the thinking inertia, is not limited to the dynamic performance of the camera, changes a technical idea, starts with the scheme design from the picture received by the camera, does not need to move the camera, and realizes dynamic measurement in a simple and low-cost mode. The specific scheme is as follows:
as shown in fig. 1 and 2, a measuring device based on machine vision includes a marking mechanism, a measurement trigger unit 1, a processing unit 8, a fast reflection mirror 4, an imaging system 6, a spectroscope 5 and a distance measuring unit 7. The imaging system 6, the distance measuring unit 7 and the measurement triggering unit 1 are electrically connected with the processing unit 8 respectively.
In this embodiment, the measurement triggering unit 1 is a photoelectric switch sensor, the processing unit 8 is an industrial PC, and the processing unit 8 may also use a PLC in other embodiments. The distance measuring unit 7 is an infrared distance measuring device. The marking mechanism is used for marking two marking points with fixed distance on the surface to be detected of the workpiece 3. In this embodiment, marking mechanism is manual marker, and marking mechanism is last to be equipped with two and to be used for drawing the touching point of mark point, and the appearance of touching the point can be similar to the writing brush, touches the face that awaits measuring of modes such as sharp accessible mark liquid to beat the mark to work piece 3. After the workpiece 3 is processed, a marking mechanism can be used for marking two marking points on the surface to be measured of the workpiece 3.
The conveyer belt is preset with a measuring section. It should be noted that the conveyor belt in the present embodiment is defaulted to a linear conveyor belt. The fast reflecting mirror 4 is positioned at the measuring section, the fast reflecting mirror 4 is arranged above the conveyor belt, and in other embodiments, the fast reflecting mirror can also be arranged at one side of the conveyor belt. The fast reflection mirror 4 is used for reflecting the image of the detection surface of the workpiece 3 in the measurement section to the spectroscope 5. The distance measuring unit 7 is positioned on one side of the reflected light of the spectroscope 5, and the imaging system 6 is positioned on one side of the transmitted light of the spectroscope 5; and the reflection distance of the spot on the surface of the beam splitter 5 to the ranging unit 7 is equal to the transmission distance of the spot to the imaging system 6.
The measurement trigger unit 1 is arranged at the start position of the measurement section of the conveyor belt and is used for sending a start signal to the processing unit 8 when the workpiece 3 on the conveyor belt is detected; the processing unit 8 is used for controlling the fast reflecting mirror 4 to rotate after receiving the start signal, so that the fast reflecting mirror 4 reflects the image of the surface to be measured of the workpiece 3 to the spectroscope 5, transmits the image to the imaging system 6 after being transmitted by the spectroscope 5, and transmits the image to the distance measuring unit 7 after being reflected by the spectroscope 5.
The processing unit 8 is further configured to analyze a midpoint of a connection line of the two marker points on the image of the imaging system 6, and record the midpoint as a target midpoint; the processing unit 8 is further configured to analyze a deviation value between the target midpoint and a reference point preset in imaging in combination with the detection data of the distance measuring unit 7, and drive the fast-reflection mirror 4 to rotate according to the deviation value, so that the deviation value continuously approaches to zero. In this embodiment, the reference point is the center point of the image. Compare in other positions with setting up the reference point, can guarantee that the face of awaiting measuring of work piece 3 is in the region that is close to the centre position all the time, chooses for use the camera of big image plane, little visual field can satisfy the demand, like this, can promote the formation of image resolution ratio, further guarantees measuring result's accuracy. The processing unit 8 also prestores the actual distance between the two marking points; the processing unit 8 is further configured to analyze a real-time distance between two mark points on the imaging according to the detection data of the imaging and ranging unit 7 of the imaging system 6, and is further configured to perform measurement calculation on the surface to be measured of the workpiece 3 according to the imaging at the time and the detection data of the ranging unit 7 at the time when the real-time distance is equal to the actual distance.
The application also provides a measuring method based on machine vision, and the measuring device based on machine vision comprises
S1, marking two mark points with fixed distance on the surface to be detected of the workpiece 3 by a marking mechanism, and enabling the surface to be detected of the workpiece 3 to face the quick reflection mirror 4;
s2, after detecting that the workpiece 3 reaches the measurement section, the measurement trigger unit 1 sends a start signal to the processing unit 8; the processing unit 8 receives the start signal and then controls the fast reflecting mirror 4 to rotate, so that the fast reflecting mirror 4 reflects the image of the surface to be measured of the workpiece 3 to the spectroscope 5, transmits the image to the imaging system 6 after being transmitted by the spectroscope 5, and transmits the image to the distance measuring unit 7 after being reflected by the spectroscope 5;
s3 and S3, the processing unit 8 analyzes the midpoint of the connecting line of the two marking points on the image of the imaging system 6, marks the midpoint as a target midpoint, analyzes the deviation value between the target midpoint and a reference point preset on the image, and drives the fast reflecting mirror 4 to rotate according to the deviation value so as to enable the deviation value to continuously approach to zero; wherein, the reference point is the central point of the imaging;
s4, the processing unit 8 analyzes the real-time distance between two mark points on the image according to the detection data of the imaging and distance measuring unit 7 of the imaging system 6, and when the real-time distance is equal to the pre-stored actual distance, the surface to be measured of the workpiece 3 is measured and calculated according to the imaging at the moment and the detection data of the distance measuring unit 7 at the moment.
The specific implementation process is as follows:
by using the scheme, the workpiece 3 to be detected is marked with two mark points with fixed distance by the marking mechanism, and the workpiece 3 is positioned on the conveying belt and the surface to be detected faces the quick reflection mirror 4. When the workpiece 3 is transferred to the start position of the measuring section, the measurement triggering unit 1 detects the workpiece 3 and sends a start signal to the processing unit 8. The processing unit 8 receives the start signal and controls the fast reflecting mirror 4 to rotate, so that the fast reflecting mirror 4 reflects the image of the surface to be measured of the workpiece 3 to the spectroscope 5, and the image is transmitted to the imaging system 6 for imaging after being transmitted by the spectroscope 5. Meanwhile, the image reflected by the beam splitter 5 is sent to the distance measuring unit 7. The reflection distance from the spot on the surface of the beam splitter 5 to the ranging unit 7 is equal to the transmission distance of the spot to the imaging system 6. The processing unit 8 can calculate the distance between two marked points on the image by the detection data of the imaging and ranging unit 7.
Then, the processing unit 8 analyzes the midpoint of the connecting line of the two marking points on the image of the imaging system 6 and records the midpoint as the target midpoint; and combining the detection data of the distance measuring unit 7, calculating a deviation value between the target midpoint and a reference point preset on imaging, and driving the fast reflecting mirror 4 to rotate according to the deviation value so that the deviation value continuously approaches to zero. Equivalently, the position of the target midpoint on the image is close to static, so that the effect that the surface to be measured of the workpiece 3 is close to static on the image is achieved. In the above process, the processing unit 8 may further continuously analyze the real-time distance between the two mark points on the image, and when the real-time distance is equal to the actual distance, it is described that the size of the surface to be measured in the image is exactly the same as the size of the actual surface to be measured (in other words, the surface to be measured is exactly perpendicular to the shooting angle of the imaging system 6, and the image is not distorted), so that the processing unit 8 measures the surface to be measured of the workpiece 3 according to the image at that time.
This application realizes dynamic measurement through controlling fast reflection mirror 4, and fast reflection mirror 4 compares with the camera, and its dynamic behavior is very outstanding, its turned angle of control that can be very accurate and light. Besides, because the factor driving the fast reflecting mirror 4 to rotate is the deviation value between the target midpoint and the reference point on the image, the image is obtained after the fast reflecting mirror 4 reflects the image to the imaging system 6, and the reflection angle is equal to the incident angle, then, compared with the direct rotating camera, the fast reflecting mirror 4 only needs to rotate half of the angle to complete the tracking of the surface to be measured of the workpiece 3, the tracking efficiency is more efficient, and because only needs to rotate half of the angle, the angular speed equivalent to the rotation is changed to half, the control precision can be further ensured. On the other hand, in the technical scheme of the application, the surface to be measured of the workpiece 3 on the picture received by the imaging system 6 is already in an approximately static state, and the imaging system 6 can realize dynamic measurement of the surface to be measured of the workpiece 3 without rotating. Since no rotation is required, there is no requirement for the dynamic performance of the imaging system 6, and only a camera with appropriate shooting capability needs to be selected.
By using the scheme, only less cost needs to be added, the dynamic measurement of the surface to be measured of the workpiece 3 can be stably realized, compared with manual detection, a special static measurement link and a special station do not need to be set, and the measurement efficiency of the surface to be measured of the workpiece 3 can be improved.
Example two
Compared with the first embodiment, the difference is that in the measuring device based on machine vision in the first embodiment, the fast reflecting mirror 4 is a single-axis fast reflecting mirror; the processing unit 8 drives the fast reflecting mirror 4 to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value of the X axis continuously approaches to zero; wherein, the positive direction of X axle is the direction of transfer of conveyer belt. In S3 of the machine vision-based measurement method of the present embodiment, the processing unit 8 drives the fast-reflection mirror 4 to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value on the X axis continuously approaches zero; wherein, the positive direction of the X axis is the conveying direction of the conveying belt. In other words, the deviation value of the target midpoint and the reference point on the Y axis tends to be stable originally, and even if the photographing angle changes, the change of the deviation value of the Y axis is very slow. Therefore, the aim that the position of the target midpoint on the imaging is close to static can be achieved only by tracking the X axis of the target midpoint. In addition, the driving of the fast reflecting mirror 4 can be more concise and stable in such a way, so that the overall stability of dynamic detection is further improved.
In addition, the processing unit 8 of the present embodiment stores the initial angle of the fast reflection mirror 4; the processing unit 8 is further configured to control the fast reflecting mirror 4 to return to the initial angle after measuring the surface of the workpiece 3 to be measured. When the worker places the workpiece 3, the worker usually places the workpiece at a position close to the middle (the position corresponding to the Y axis is relatively fixed), and when the dynamic measurement is started, the workpiece 3 is at the initial position of the measurement section (the position corresponding to the X axis is relatively fixed). In conclusion, after the dynamic measurement is started, the position of the workpiece 3 on the conveyor belt is relatively fixed, and the fast reflecting mirror 4 can accurately track the surface to be measured of the workpiece 3 as early as possible by reasonably setting the initial angle of the fast reflecting mirror 4.
EXAMPLE III
Different from the first embodiment, the present embodiment further includes an ending triggering unit 2 and an alarm unit electrically connected to the processing unit 8, respectively; the end triggering structure is a photoelectric switch sensor, the end triggering unit 2 is arranged at the end position of the measuring section of the conveyor belt and used for sending an end signal to the processing unit 8 when the workpiece 3 on the conveyor belt is detected; the processing unit 8 is further configured to control the alarm unit to issue an alarm when the end signal is received but the to-be-measured surface of the corresponding workpiece 3 has not been measured. The alarm unit in this embodiment is a loudspeaker.
The machine vision-based measuring method of the present embodiment further includes S5, when the workpiece 3 on the conveyor belt is detected, the end triggering unit 2 is configured to send an end signal to the processing unit 8; if the surface to be measured of the corresponding workpiece 3 has not been measured yet when the end signal is received, the processing unit 8 controls the alarm unit to give an alarm.
If the workpiece 3 has reached the end of the measurement section and the surface to be measured of the corresponding workpiece 3 is not measured yet, it indicates that the situation that the shooting angle is perpendicular to the surface to be measured does not occur in the whole measurement section, and the workpiece 3 is placed in a problem. Therefore, an alarm is given to let the worker know the situation and measure the surface to be measured of the workpiece 3 alone.
The foregoing is merely an example of the present invention, and common general knowledge in the field of known specific structures and characteristics is not described herein in any greater extent than that known in the art at the filing date or prior to the priority date of the application, so that those skilled in the art can now appreciate that all of the above-described techniques in this field and have the ability to apply routine experimentation before this date can be combined with one or more of the present teachings to complete and implement the present invention, and that certain typical known structures or known methods do not pose any impediments to the implementation of the present invention by those skilled in the art. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.
Claims (10)
1. A measuring device based on machine vision is characterized in that: the conveyor belt is preset with a measuring section; the device comprises a marking mechanism, a measurement trigger unit, a processing unit, a fast reflection mirror, an imaging system, a spectroscope and a distance measuring unit; the processing unit is respectively and electrically connected with the measurement trigger unit, the imaging system and the distance measuring unit;
the marking mechanism is used for marking two marking points with fixed distance on the surface to be detected of the workpiece; the fast reflection mirror is positioned in the measuring section and used for reflecting the detection surface image of the workpiece in the measuring section to the spectroscope; the distance measuring unit is positioned on one side of the reflected light of the spectroscope, and the imaging system is positioned on one side of the transmitted light of the spectroscope; the reflection distance from the light spot on the surface of the spectroscope to the ranging unit is equal to the transmission distance from the light spot to the imaging system;
the measuring trigger unit is arranged at the starting position of the measuring section of the conveyor belt and used for sending a starting signal to the processing unit when a workpiece on the conveyor belt is detected; the processing unit is used for controlling the fast reflecting mirror to rotate after receiving the starting signal, so that the fast reflecting mirror reflects the image of the surface to be measured of the workpiece to the spectroscope, transmits the image to the imaging system after being transmitted by the spectroscope, and transmits the image to the distance measuring unit after being reflected by the spectroscope;
the processing unit is also used for analyzing the midpoint of the connecting line of the two marking points on the image of the imaging system and recording the midpoint as the target midpoint; the processing unit is also used for analyzing a deviation value between a target center point and a reference point preset on imaging by combining the detection data of the ranging unit, and driving the fast reflecting mirror to rotate according to the deviation value so that the deviation value continuously approaches to zero; the processing unit also prestores the actual distance between the two marking points; the processing unit is also used for analyzing the real-time distance between two mark points on the imaging according to the detection data of the imaging and ranging unit of the imaging system, and is also used for measuring and calculating the surface to be measured of the workpiece according to the imaging at the moment and the detection data of the ranging unit at the moment when the real-time distance is equal to the actual distance.
2. The machine-vision based measurement device of claim 1, wherein: the fast reflecting mirror is a single-axis fast reflecting mirror; the processing unit drives the fast reflecting mirror to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value of the X axis continuously approaches to zero; wherein, the positive direction of X axle is the direction of transfer of conveyer belt.
3. The machine-vision based measurement device of claim 2, wherein: the system also comprises an ending triggering unit and an alarm unit which are respectively electrically connected with the processing unit; the end triggering unit is arranged at the end position of the measuring section of the conveyor belt and used for sending an end signal to the processing unit when the workpiece on the conveyor belt is detected; the processing unit is also used for controlling the alarm unit to give an alarm when the end signal is received but the surface to be measured of the corresponding workpiece is not measured.
4. The machine-vision based measurement device of claim 3, wherein: the measurement trigger unit and the ending trigger unit are both photoelectric switch sensors.
5. The machine-vision based measurement device of claim 4, wherein: the reference point is the center point of the image.
6. The machine-vision based measurement device of claim 5, wherein: the processing unit stores the initial angle of the fast reflecting mirror; the processing unit is also used for controlling the quick reflection mirror to recover to the initial angle after measuring the surface to be measured of the workpiece.
7. A measuring method based on machine vision is characterized in that: use of the machine vision based measuring device of any of claims 1-6, comprising:
s1, marking two mark points with fixed distance on the surface to be detected of the workpiece by a marking mechanism, and enabling the surface to be detected of the workpiece to face the quick reflection mirror;
s2, after the workpiece is detected to reach the measuring section, the measuring trigger unit sends a starting signal to the processing unit; the processing unit receives the starting signal and then controls the fast reflecting mirror to rotate, so that the fast reflecting mirror reflects the image of the surface to be measured of the workpiece to the spectroscope, transmits the image to the imaging system after being transmitted by the spectroscope, and transmits the image to the distance measuring unit after being reflected by the spectroscope;
s3, the processing unit analyzes the midpoint of the connecting line of the two marking points on the image of the imaging system and marks the midpoint as a target midpoint, analyzes the deviation value between the target midpoint and a reference point preset on the image, and drives the fast reflection mirror to rotate according to the deviation value so that the deviation value continuously approaches to zero;
and S4, the processing unit analyzes the real-time distance between two marking points on the imaging according to the detection data of the imaging and ranging unit of the imaging system, and when the real-time distance is equal to the pre-stored actual distance, the processing unit measures and calculates the surface to be measured of the workpiece according to the imaging at the moment and the detection data of the ranging unit at the moment.
8. The machine-vision based measurement method of claim 7, wherein: in S3, the processing unit drives the fast-response mirror to rotate according to the deviation value of the target midpoint and the reference point on the X axis, so that the deviation value of the X axis continuously approaches to zero; wherein, the positive direction of X axle is the direction of transfer of conveyer belt.
9. The machine-vision based measurement method of claim 8, wherein: s5, when the workpiece on the conveyor belt is detected, the end trigger unit is set to send an end signal to the processing unit; and if the surface to be measured of the corresponding workpiece is not measured when the end signal is received, the processing unit controls the alarm unit to give an alarm.
10. The machine-vision based measurement method of claim 9, wherein: in S3, the reference point is the center point of the image.
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