CN112082450B - Cylinder diameter measuring method and device - Google Patents
Cylinder diameter measuring method and device Download PDFInfo
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- CN112082450B CN112082450B CN202010997037.1A CN202010997037A CN112082450B CN 112082450 B CN112082450 B CN 112082450B CN 202010997037 A CN202010997037 A CN 202010997037A CN 112082450 B CN112082450 B CN 112082450B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/08—Measuring arrangements characterised by the use of mechanical techniques for measuring diameters
Abstract
The embodiment of the invention provides a method and a device for measuring the diameter of a cylinder. The method comprises the following steps: irradiating the cylinder to be measured by monochromatic parallel beams, and respectively acquiring Fresnel diffraction patterns of the diameter edge of the cylinder to be measured at two positions on an optical axis to generate a first diffraction light intensity diagram and a second diffraction light intensity diagram; acquiring the diameter of the cylinder to be measured according to the first diffraction light intensity diagram and the second diffraction light intensity diagram; the optical axis is perpendicular to a bus of the cylinder to be measured. According to the method and the device for measuring the diameter of the cylinder, provided by the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction effect of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Description
Technical Field
The invention relates to the field of optical measurement, in particular to a method and a device for measuring the diameter of a cylinder.
Background
In industrial application, the measurement of one-dimensional dimension such as the diameter of a cylinder is more in demand, such as the measurement of the diameter of a workpiece such as a rolling bearing, a steel pipe, a round blank and the like. The measurement range of the requirements is large, the precision requirement is high, and the method is an important research direction in geometric measurement. With the rapid development of computer technology and image sensor technology, the application of image-based non-contact cylinder diameter measurement is more and more extensive; the method has the advantages of high measurement speed and no damage to the surface of the measured piece, and has very important application value in industrial production.
Image-based cylinder diameter measurement is mainly achieved by imaging the edge profile of the cylinder. Currently, an imaging system is generally used to image a cylinder to be measured, and boundary processing is performed on the acquired image to measure the diameter of the cylinder. However, the boundary extraction accuracy is low due to the boundary blurring caused by the beam diffraction, which affects the measurement accuracy of the final measurement result.
Disclosure of Invention
The embodiment of the invention provides a method and a device for measuring the diameter of a cylinder, which are used for solving or at least partially solving the defect of low measurement precision in the prior art.
In a first aspect, an embodiment of the present invention provides a cylinder diameter measurement method, including:
irradiating the cylinder to be measured by monochromatic parallel beams, and respectively acquiring Fresnel diffraction patterns of the diameter edge of the cylinder to be measured at two positions on an optical axis to generate a first diffraction light intensity diagram and a second diffraction light intensity diagram;
acquiring the diameter of the cylinder to be detected according to the first diffraction light intensity diagram and the second diffraction light intensity diagram;
and the optical axis is vertical to a bus of the cylinder to be detected.
Preferably, the specific step of obtaining the diameter of the cylinder to be measured according to the first diffracted light intensity map and the second diffracted light intensity map includes:
respectively obtaining the distance between light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph;
and acquiring the diameter of the cylinder to be detected according to the wavelength of the monochromatic parallel light beams, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph.
Preferably, the specific step of obtaining the diameter of the cylinder to be measured according to the wavelength of the monochromatic parallel light beam, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffracted light intensity graph and the second diffracted light intensity graph includes:
obtaining the diameter of the cylinder to be measured by the following formula
Wherein D represents the diameter of the cylinder to be measured; λ represents the wavelength of the monochromatic parallel beam; dx represents the distance between the two positions; l is1Representing the distance between light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity diagram; l is2Representing the intensity of the second diffraction to be measuredDistance between light intensity peak points of the diameter edges of the cylinders.
Preferably, the step of irradiating the cylinder to be measured with the monochromatic parallel light beams, respectively obtaining fresnel diffraction patterns at the diameter edge of the cylinder to be measured at two positions on the optical axis, and the step of generating the first diffraction light intensity pattern and the second diffraction light intensity pattern includes:
if the diameter of the cylinder to be detected is known to be larger than the effective diameter of the monochromatic parallel light beams through estimation, a first edge of the diameter of the cylinder to be detected is irradiated by a first sub monochromatic parallel light beam, Fresnel diffraction patterns of the first edge are respectively obtained at two positions on a first optical axis, a first sub light intensity pattern and a second sub light intensity pattern are generated, a second edge of the diameter of the cylinder to be detected is irradiated by a second sub monochromatic parallel light beam, Fresnel diffraction patterns of the second edge are respectively obtained at two positions on a second optical axis, and a third sub light intensity pattern and a fourth sub light intensity pattern are generated;
wherein the first optical axis is parallel to the second optical axis; in a plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis; the two positions on the first optical axis are respectively the same as the two positions on the second optical axis; the first diffracted intensity pattern comprises the first sub-intensity pattern and the third sub-intensity pattern; the second diffracted light intensity pattern comprises the second sub-light intensity pattern and the fourth sub-light intensity pattern.
Preferably, the specific step of respectively obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffracted light intensity map and the second diffracted light intensity map includes:
according to the distance between the light intensity peak point of the first edge and the first optical axis in the first sub-light intensity map, the distance between the peak point of the intensity of the second edge and the second optical axis in the third sub-intensity map, and the distance between the first optical axis and the second optical axis, obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph, and according to the distance between the light intensity peak point of the first edge in the second sub-light intensity graph and the first optical axis, the distance between the peak point of the intensity of the second edge and the second optical axis in the fourth sub-intensity map, and the distance between the first optical axis and the second optical axis is used for obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the second diffraction light intensity graph.
Preferably, the step of irradiating the cylinder to be measured with the monochromatic parallel light beam, acquiring fresnel diffraction patterns at the diameter edge of the cylinder to be measured at two positions on the optical axis, and generating the first diffraction light intensity pattern and the second diffraction light intensity pattern further includes:
if the diameter of the cylinder to be measured is known to be smaller than the effective diameter of the monochromatic parallel light beams through estimation, the cylinder to be measured is irradiated through the first sub-monochromatic parallel light beams, Fresnel diffraction patterns on the diameter edge of the cylinder to be measured are respectively obtained at two positions on the first optical axis, and the first diffraction light intensity graph and the second diffraction light intensity graph are generated.
In a second aspect, an embodiment of the present invention provides a cylinder diameter measuring apparatus, including:
the monochromatic parallel beam module is used for emitting monochromatic parallel beams to irradiate the cylinder to be detected;
and the image sensor is used for acquiring the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured on the optical axis.
Preferably, the monochromatic parallel beam module comprises a first monochromatic parallel beam submodule and a second monochromatic parallel beam submodule; the image sensor comprises a first sub-image sensor and a second sub-image sensor;
the first monochromatic parallel beam submodule is used for emitting a first sub-monochromatic parallel beam to irradiate a first edge of the diameter of the cylinder to be detected;
the first sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of the first edge at two positions on a first optical axis to generate a first sub-light intensity diagram and a second sub-light intensity diagram;
the second monochromatic parallel beam submodule is used for emitting a second sub-monochromatic parallel beam to irradiate a second edge of the diameter of the cylinder to be measured;
the second sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of the second edge at two positions on a second optical axis to generate a third sub-light intensity diagram and a fourth sub-light intensity diagram;
wherein the first optical axis is parallel to the second optical axis; in a plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis.
Preferably, the monochromatic parallel beam module comprises a monochromatic point light source and a collimating lens.
Preferably, the first monochromatic parallel beam submodule comprises a monochromatic point light source and a collimating lens; the second monochromatic parallel beam submodule comprises a monochromatic point light source and a collimating lens.
According to the method and the device for measuring the diameter of the cylinder, provided by the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction effect of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved. Furthermore, fewer devices are needed for measurement, and the cost is lower.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a schematic flow chart of a method for measuring a diameter of a cylinder according to an embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating distances between light intensity peak points in a cylinder diameter measurement method according to an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating distances between light intensity peak points in a cylinder diameter measurement method according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a cylinder diameter measuring apparatus according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to overcome the above problems in the prior art, an embodiment of the present invention provides a method and an apparatus for measuring a diameter of a cylinder, and the inventive concept is to provide a method for measuring a diameter of a cylinder based on a monochromatic parallel light beam diffraction profile processing, wherein a shadow map formed by projection is received by a corresponding image sensor by projecting a small-sized monochromatic parallel light beam to an edge of the cylinder, and then an edge profile in the shadow map is detected according to a light intensity distribution characteristic under a light beam diffraction effect, so as to achieve a diameter measurement purpose. The method has high measurement precision, is not influenced by the size of the light beam, and has a large measurement size range.
Fig. 1 is a schematic flow chart of a cylinder diameter measuring method according to an embodiment of the present invention. As shown in fig. 1, the method includes: step S101, a cylinder to be measured is irradiated by monochromatic parallel light beams, Fresnel diffraction patterns of the diameter edge of the cylinder to be measured are respectively obtained at two positions on an optical axis, and a first diffraction light intensity graph and a second diffraction light intensity graph are generated.
The optical axis is perpendicular to a bus of the cylinder to be measured.
Specifically, a cylinder to be measured is placed in a cylinder diameter measuring device. The cylinder diameter measuring device may include: a monochromatic parallel beam module and an image sensor.
The monochromatic parallel beam module is used for emitting monochromatic parallel beams to irradiate the cylinder to be detected;
and the image sensor is used for acquiring the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured on the optical axis.
The coordinate system is oxyz. The optical axis of the monochromatic parallel beam module is parallel to the ox axis and passes through the center of the image sensor and is perpendicular to the sensor plane.
The image sensor can be moved along the ox axis by a distance denoted dx. The wavelength of the light source (i.e., the wavelength of the monochromatic parallel beams) is denoted as λ, and the effective diameter of each monochromatic parallel beam is a.
The image sensor does not include a lens. The image sensor can be a CCD or CMOS image sensor.
The monochromatic parallel light beams irradiate the cylinder to be detected to form Fresnel diffraction patterns on two edges of the cylinder to be detected, and the image sensor collects the Fresnel diffraction patterns at two positions with a distance of dx and records the Fresnel diffraction patterns as a first diffraction light intensity graph 1_0 and a second diffraction light intensity graph 2_0 respectively.
S102, acquiring the diameter of the cylinder to be measured according to the first diffraction light intensity diagram and the second diffraction light intensity diagram;
specifically, according to the light intensity distribution characteristics under the action of light beam diffraction, a first diffraction light intensity graph and a second diffraction light intensity graph are respectively processed, and the edge profiles of cylinders in the first diffraction light intensity graph and the second diffraction light intensity graph are determined; and then based on the optical principle, obtaining the diameter of the cylinder to be measured according to the edge profiles of the cylinders in the first diffraction light intensity diagram and the second diffraction light intensity diagram.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved. Furthermore, fewer devices are needed for measurement, and the cost is lower.
Based on the content of the above embodiments, the specific step of obtaining the diameter of the cylinder to be measured according to the first diffraction light intensity diagram and the second diffraction light intensity diagram includes: and respectively obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph.
Specifically, fig. 2 is a schematic diagram of distances between light intensity peak points in the cylinder diameter measurement method according to the embodiment of the present invention, and as shown in fig. 2, the interval of the light intensity peak points of two edges of the cylinder in the first diffracted light intensity graph 1_0 in the oy axis direction, that is, the distance L between the light intensity peak points is calculated1(ii) a Calculating the interval of the light intensity peak points of the two edges of the cylinder in the second diffracted light intensity graph 2_0 in the oy axis direction, i.e. the distance L between the light intensity peak points2。
The dotted circle represents the cylinder to be measured.
And acquiring the diameter of the cylinder to be measured according to the wavelength of the monochromatic parallel light beams, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph and the second diffraction light intensity graph.
In particular, based on optical principles, according to L1、L2And calculating the wavelength lambda and dx of the monochromatic parallel light beams to obtain the diameter of the cylinder to be measured.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Based on the content of each embodiment, the specific steps of obtaining the diameter of the cylinder to be measured according to the wavelength of the monochromatic parallel light beam, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph and the second diffraction light intensity graph include:
the diameter of the cylinder to be measured is obtained by the following formula
Wherein D represents the diameter of the cylinder to be measured; λ represents the wavelength of the monochromatic parallel beam; dx represents the distance between the two positions; l is1Representing the distance between light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity diagram; l is2And the distance between light intensity peak points of the diameter edge of the cylinder to be measured in the second diffraction light intensity diagram is shown.
In particular, according to L1、L2The wavelengths lambda and dx of the monochromatic parallel beams, and the formula for calculating the diameter D of the cylinder to be measured is
According to the principle of Fresnel diffraction, the distance between the peak value of the light intensity distribution of the straight-edge Fresnel diffraction under the irradiation of parallel monochromatic light and the geometric edge is
(where λ is the wavelength of the parallel monochromatic light and x is the distance between the edge of the cylinder diameter and the image sensor), i.e., D ═ L02m (D is the diameter of the cylinder, L)0The distance between two peak points).
It will be appreciated that the diametrical edge of the cylinder may be considered a straight line and may be approximated as a straight line.
For the case where the image sensor is located at two different locations:
wherein x is1Representing the distance between the diameter edge of the cylinder and the image sensor when in the first position.
If x1>>dx is then
Therefore, the air conditioner is provided with a fan,
therefore, the temperature of the molten metal is controlled,
according to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Based on the content of each embodiment, the cylinder to be measured is irradiated by the monochromatic parallel light beams, the fresnel diffraction patterns of the diameter edge of the cylinder to be measured are respectively obtained at two positions on the optical axis, and the specific steps of generating the first diffraction light intensity diagram and the second diffraction light intensity diagram comprise: if the diameter of the cylinder to be measured is larger than the effective diameter of the monochromatic parallel light beams through prediction, a first edge of the diameter of the cylinder to be measured is irradiated by the first sub monochromatic parallel light beams, Fresnel diffraction patterns of the first edge are respectively obtained at two positions on a first optical axis, a first sub light intensity pattern and a second sub light intensity pattern are generated, a second edge of the diameter of the cylinder to be measured is irradiated by the second sub monochromatic parallel light beams, Fresnel diffraction patterns of the second edge are respectively obtained at two positions on a second optical axis, and a third sub light intensity pattern and a fourth sub light intensity pattern are generated.
The first optical axis is parallel to the second optical axis; in the plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis; two positions on the first optical axis which are respectively the same as two positions on the second optical axis; the first diffracted intensity pattern comprises a first sub-intensity pattern and a third sub-intensity pattern; the second diffracted intensity pattern comprises a second sub-intensity pattern and a fourth sub-intensity pattern.
In particular, the monochromatic parallel beam module may include a first and a second identical monochromatic parallel beam sub-module; the image sensor includes a first sub-image sensor and a second sub-image sensor.
The optical axes of the first monochromatic parallel beam submodule and the second monochromatic parallel beam submodule are parallel, are respectively a first optical axis and a second optical axis, and are parallel to the ox axis. The first optical axis and the second optical axis respectively pass through the centers of the first sub-image sensor and the second sub-image sensor and are respectively perpendicular to the sensor surfaces of the first sub-image sensor and the second sub-image sensor.
The interval between the first optical axis and the second optical axis in the oy axis direction is denoted as L.
The relative position of the first monochromatic parallel beam submodule and the second monochromatic parallel beam submodule in the ox axis direction is 0.
The placement rule of the cylinder to be tested comprises: and (3) estimating the relation between the diameters D and a of the cylinder, if D is larger than or equal to a, adjusting the interval L between the first optical axis and the second optical axis to ensure that two edges (such as upper and lower edge points) of the cylinder to be detected are respectively positioned at the positions of the first optical axis and the second optical axis as far as possible, and recording the numerical value of L.
The first monochromatic parallel light beam submodule emits a first sub monochromatic parallel light beam to irradiate a first edge (such as an upper edge) of the diameter of the cylinder to be detected, the first sub image sensor respectively acquires Fresnel diffraction patterns of the first edge at two positions which are away from each other by dx in the ox axis direction on the first optical axis, and a first sub light intensity graph and a second sub light intensity graph are generated.
The first sub-intensity map is a portion of the first diffracted intensity map and the second sub-intensity map is a portion of the first diffracted intensity map.
The second monochromatic parallel light beam submodule emits a second sub monochromatic parallel light beam to irradiate a second edge (such as a lower edge) of the diameter of the cylinder to be detected, the second sub image sensor respectively acquires Fresnel diffraction patterns of the second edge at two positions which are away from each other by dx in the ox axis direction on the second optical axis, and a third sub light intensity diagram and a fourth sub light intensity diagram are generated.
The third sub intensity map is a portion of the first diffracted intensity map and the fourth sub intensity map is a portion of the first diffracted intensity map.
It should be noted that, the position where the first sub-image sensor acquires the first sub-intensity map and the position where the second sub-image sensor acquires the third sub-intensity map are set to be 0 relative to each other in the ox axis direction; the position of the first sub-image sensor for acquiring the second sub-intensity map and the position of the second sub-image sensor for acquiring the fourth sub-intensity map are set to be 0 in the ox axis direction.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Based on the content of each embodiment, the specific steps of respectively obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph and the second diffraction light intensity graph include: and acquiring the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity diagram according to the distance between the light intensity peak point of the first edge and the first optical axis in the first sub-light intensity diagram, the distance between the light intensity peak point of the second edge and the second optical axis in the third sub-light intensity diagram and the distance between the first optical axis and the second optical axis in the fourth sub-light intensity diagram and the distance between the first optical axis and the second optical axis in the second diffraction light intensity diagram.
Specifically, fig. 3 is a schematic diagram of distances between light intensity peak points in the cylinder diameter measuring method according to the embodiment of the present invention, as shown in fig. 3, a distance between a light intensity peak point of a first edge in a first sub-light intensity diagram and a first optical axis, a distance between a light intensity peak point of a second edge in a third sub-light intensity diagram and a second optical axis, a distance between a light intensity peak point of a first edge in a second sub-light intensity diagram and a first optical axis, and a distance between a light intensity peak point of a second edge in a fourth sub-light intensity diagram and a second optical axis are respectively denoted as L11、L12、L21、L22。
The optical axes correspond to the centers of the sensors in the oy direction, respectively, so that the optical axes (dotted lines) in fig. 3 also indicate the center positions of the two sensors.
Therefore, in the first diffraction light intensity diagram, the distance L between the light intensity peak points of the diameter edge of the cylinder to be measured1Is calculated by the formula L1＝L+L11+L12(ii) a In the second diffraction light intensity diagram, the distance L between the light intensity peak points of the diameter edge of the cylinder to be measured2Is calculated by the formula L2＝L+L21+L22。
In addition, L is11、L12、L21、L22The signs of (A) are specified as: the first optical axis is located between the light intensity peak point of the first edge and the light intensity peak point of the second edge, then L11And L21Is positive, the first optical axis is located outside the light intensity peak point of the first edge and the light intensity peak point of the second edge, then L11And L21The sign of (a) is negative; the second optical axis is located between the light intensity peak point of the first edge and the light intensity peak point of the second edge, and L12And L22Is positive, the second optical axis is located outside the light intensity peak point of the first edge and the light intensity peak point of the second edge, then L12And L22The sign of (a) is negative.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Based on the content of each embodiment, the cylinder to be measured is irradiated by the monochromatic parallel light beam, the fresnel diffraction patterns at the diameter edge of the cylinder to be measured are respectively obtained at two positions on the optical axis, and the specific steps of generating the first diffraction light intensity diagram and the second diffraction light intensity diagram further include: if the diameter of the cylinder to be measured is smaller than the effective diameter of the monochromatic parallel light beams through prediction, the cylinder to be measured is irradiated by the first sub-monochromatic parallel light beams, Fresnel diffraction patterns of the diameter edge of the cylinder to be measured are respectively obtained at two positions on the first optical axis, and a first diffraction light intensity graph and a second diffraction light intensity graph are generated.
Specifically, the placement rule of the cylinder to be tested further includes: and (3) estimating the relation between the diameters D and a of the cylinder, if D < a, placing the cylinder to be measured in a measuring system, and simultaneously ensuring that two edges of the diameter can be simultaneously received by corresponding sensors in the measuring system.
The measuring system is formed by a first monochromatic parallel beam submodule and a first sub-image sensor, or formed by a second monochromatic parallel beam submodule and a second sub-image sensor.
It can be understood that the measurement of a cylinder of small dimensions is performed by using one of the sets of monochromatic parallel beam projections + image acquisition systems; the large-size cylinder can be measured by adjusting the distance between the two sets of systems, the distance between the two sets of systems is adjustable, and the measurement of the large-scale size can be realized. The method has high measurement precision, is not influenced by the size of the light beam, and has a large measurement size range.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved.
Fig. 4 is a schematic structural diagram of a cylinder diameter measuring apparatus according to an embodiment of the present invention. Based on the content of the above embodiments, as shown in fig. 4, the apparatus includes a monochromatic parallel beam module 401 and an image sensor 402, wherein:
the monochromatic parallel beam module 401 is used for emitting monochromatic parallel beams to irradiate the cylinder to be detected;
and the image sensor 402 is used for acquiring a Fresnel diffraction pattern of the diameter edge of the cylinder to be measured on the optical axis.
Specifically, the coordinate system is oxyz. The optical axis of the monochromatic parallel beam module 401 is parallel to the ox axis and passes through the center of the image sensor 402 and is perpendicular to the sensor plane.
The image sensor 402 can move along the ox axis by a distance denoted dx. The wavelength of the light source (i.e., the wavelength of the monochromatic parallel beams) is denoted as λ, and the effective diameter of each monochromatic parallel beam is a.
The image sensor does not include a lens. The image sensor can be a CCD or CMOS image sensor.
The monochromatic parallel light beams irradiate the cylinder to be detected to form Fresnel diffraction patterns on two edges of the cylinder to be detected, and the image sensor collects the Fresnel diffraction patterns at two positions with a distance of dx and records the Fresnel diffraction patterns as a first diffraction light intensity graph 1_0 and a second diffraction light intensity graph 2_0 respectively.
According to the light intensity distribution characteristics under the action of light beam diffraction, the first diffraction light intensity graph and the second diffraction light intensity graph are respectively processed, and the edge profiles of the cylinders in the first diffraction light intensity graph and the second diffraction light intensity graph are determined; and then based on the optical principle, obtaining the diameter of the cylinder to be measured according to the edge profiles of the cylinders in the first diffraction light intensity diagram and the second diffraction light intensity diagram.
The specific method and process for implementing the corresponding function of each module included in the cylinder diameter measuring device provided in the embodiments of the present invention are described in the embodiments of the cylinder diameter measuring method, and are not described herein again.
The cylinder diameter measuring apparatus is used for the cylinder diameter measuring method of the foregoing embodiments. Therefore, the description and definition in the cylinder diameter measuring method in the foregoing embodiments can be used for understanding the execution modules in the embodiments of the present invention.
According to the embodiment of the invention, the diameter of the cylinder to be measured is obtained according to the Fresnel diffraction pattern of the diameter edge of the cylinder to be measured, the influence of the diffraction action of the cylinder edge under the irradiation of the monochromatic parallel light beams is considered, the edge of the cylinder can be more accurately extracted, a more accurate measurement result can be obtained, and the measurement precision can be improved. Furthermore, fewer devices are needed for measurement, and the cost is lower.
Based on the content of the above embodiments, the monochromatic parallel beam module comprises a first monochromatic parallel beam submodule and a second monochromatic parallel beam submodule; the image sensor comprises a first sub-image sensor and a second sub-image sensor;
the first monochromatic parallel beam submodule is used for emitting a first sub monochromatic parallel beam to irradiate a first edge of the diameter of the cylinder to be measured;
the first sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of a first edge at two positions on a first optical axis to generate a first sub-light intensity diagram and a second sub-light intensity diagram;
the second monochromatic parallel beam submodule is used for emitting a second sub monochromatic parallel beam to irradiate a second edge of the diameter of the cylinder to be measured;
the second sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of a second edge at two positions on a second optical axis to generate a third sub-light intensity diagram and a fourth sub-light intensity diagram;
the first optical axis is parallel to the second optical axis; in the plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis.
In particular, the monochromatic parallel beam module may include a first monochromatic parallel beam submodule and a second monochromatic parallel beam submodule; the image sensor may include a first sub-image sensor and a second sub-image sensor.
The optical axes of the first monochromatic parallel beam submodule and the second monochromatic parallel beam submodule are parallel, are respectively a first optical axis and a second optical axis, and are parallel to the ox axis. The first optical axis and the second optical axis respectively pass through the centers of the first sub-image sensor and the second sub-image sensor and are respectively perpendicular to the sensor surfaces of the first sub-image sensor and the second sub-image sensor.
The interval between the first optical axis and the second optical axis in the oy axis direction is denoted as L.
The relative position of the first monochromatic parallel beam submodule and the second monochromatic parallel beam submodule in the ox axis direction is 0.
The first monochromatic parallel beam submodule and the first sub-image sensor form a measuring system 1, and the second monochromatic parallel beam submodule and the second sub-image sensor form a measuring system 2.
Based on the content of the above embodiments, the monochromatic parallel beam module includes the monochromatic point light source and the collimating lens.
Specifically, the monochromatic parallel light beam module may include a monochromatic point light source and a collimating lens, and monochromatic light emitted from the monochromatic point light source passes through the collimating lens to obtain a monochromatic parallel light beam.
The device needed by the measurement is less, and the cost is lower.
Based on the content of the above embodiments, the first monochromatic parallel beam submodule includes a monochromatic point light source and a collimating lens; the second monochromatic parallel beam submodule includes a monochromatic point light source and a collimating lens.
Specifically, the first monochromatic parallel beam submodule may include a monochromatic point light source and a collimating lens, and monochromatic light emitted from the monochromatic point light source passes through the collimating lens to obtain a first sub-monochromatic parallel beam.
The second monochromatic parallel beam submodule can comprise a monochromatic point light source and a collimating lens, and monochromatic light emitted by the monochromatic point light source passes through the collimating lens to obtain a second sub-monochromatic parallel beam.
The device needed by the measurement is less, and the cost is lower.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. It is understood that the above-described technical solutions may be embodied in the form of a software product, which may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method of the above-described embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (6)
1. A cylinder diameter measuring method, comprising:
irradiating the cylinder to be measured by monochromatic parallel beams, and respectively acquiring Fresnel diffraction patterns of the diameter edge of the cylinder to be measured at two positions on an optical axis to generate a first diffraction light intensity diagram and a second diffraction light intensity diagram;
acquiring the diameter of the cylinder to be detected according to the first diffraction light intensity diagram and the second diffraction light intensity diagram;
the optical axis is perpendicular to a bus of the cylinder to be detected;
the specific step of obtaining the diameter of the cylinder to be measured according to the first diffraction light intensity diagram and the second diffraction light intensity diagram comprises the following steps:
respectively obtaining the distance between light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph;
acquiring the diameter of the cylinder to be detected according to the wavelength of the monochromatic parallel light beams, the distance between the two positions and the distance between light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph;
the cylinder to be measured is irradiated through monochromatic parallel light beams, Fresnel diffraction patterns of the diameter edge of the cylinder to be measured are respectively obtained at two positions on an optical axis, and the specific steps of generating a first diffraction light intensity diagram and a second diffraction light intensity diagram comprise:
if the diameter of the cylinder to be detected is known to be larger than the effective diameter of the monochromatic parallel light beams through estimation, a first edge of the diameter of the cylinder to be detected is irradiated by a first sub monochromatic parallel light beam, Fresnel diffraction patterns of the first edge are respectively obtained at two positions on a first optical axis, a first sub light intensity pattern and a second sub light intensity pattern are generated, a second edge of the diameter of the cylinder to be detected is irradiated by a second sub monochromatic parallel light beam, Fresnel diffraction patterns of the second edge are respectively obtained at two positions on a second optical axis, and a third sub light intensity pattern and a fourth sub light intensity pattern are generated;
wherein the first optical axis is parallel to the second optical axis; in a plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis; the two positions on the first optical axis are respectively the same as the two positions on the second optical axis; the first diffracted intensity pattern comprises the first sub-intensity pattern and the third sub-intensity pattern; the second diffracted intensity pattern comprises the second sub-intensity pattern and the fourth sub-intensity pattern; the monochromatic parallel beams comprise the first sub-monochromatic parallel beams and the second sub-monochromatic parallel beams;
the specific steps of respectively obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph and the second diffraction light intensity graph comprise:
according to the distance between the light intensity peak point of the first edge and the first optical axis in the first sub-light intensity map, the distance between the peak point of the intensity of the second edge and the second optical axis in the third sub-intensity map, and the distance between the first optical axis and the second optical axis, obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph, and according to the distance between the light intensity peak point of the first edge in the second sub-light intensity graph and the first optical axis, the distance between the peak point of the intensity of the second edge and the second optical axis in the fourth sub-intensity map, and the distance between the first optical axis and the second optical axis is used for obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the second diffraction light intensity graph.
2. The cylinder diameter measuring method according to claim 1, wherein the specific step of obtaining the diameter of the cylinder to be measured according to the wavelength of the monochromatic parallel light beam, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first and second diffracted light intensity graphs comprises:
obtaining the diameter of the cylinder to be measured by the following formula
Wherein D represents the diameter of the cylinder to be measured; λ represents the wavelength of the monochromatic parallel beam; dx represents the distance between the two positions; l is1Representing the distance between light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity diagram; l is2And the distance between light intensity peak points of the diameter edge of the cylinder to be measured in the second diffraction light intensity diagram is shown.
3. The method for measuring the diameter of the cylinder according to claim 1, wherein the steps of irradiating the cylinder to be measured with the monochromatic parallel light beams, obtaining fresnel diffraction patterns of the diameter edge of the cylinder to be measured at two positions on the optical axis, and generating the first diffraction intensity pattern and the second diffraction intensity pattern further comprise:
if the diameter of the cylinder to be measured is smaller than the effective diameter of the monochromatic parallel light beams through prediction, the cylinder to be measured is irradiated by the first sub-monochromatic parallel light beams, Fresnel diffraction patterns of the diameter edge of the cylinder to be measured are respectively obtained at two positions on the first optical axis, and the first diffraction light intensity graph and the second diffraction light intensity graph are generated.
4. A cylinder diameter measuring device, comprising:
the monochromatic parallel beam module is used for emitting monochromatic parallel beams to irradiate the cylinder to be detected;
the image sensor is used for acquiring a Fresnel diffraction pattern of the diameter edge of the cylinder to be detected on an optical axis;
the monochromatic parallel beam module comprises a first monochromatic parallel beam submodule and a second monochromatic parallel beam submodule; the image sensor comprises a first sub-image sensor and a second sub-image sensor;
the first monochromatic parallel beam submodule is used for emitting a first sub-monochromatic parallel beam to irradiate a first edge of the diameter of the cylinder to be detected;
the first sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of the first edge at two positions on a first optical axis to generate a first sub-light intensity diagram and a second sub-light intensity diagram;
the second monochromatic parallel beam submodule is used for emitting a second sub-monochromatic parallel beam to irradiate a second edge of the diameter of the cylinder to be measured;
the second sub-image sensor is used for respectively acquiring Fresnel diffraction patterns of the second edge at two positions on a second optical axis to generate a third sub-light intensity diagram and a fourth sub-light intensity diagram;
wherein the first optical axis is parallel to the second optical axis; in a plane where the first optical axis and the second optical axis are located, the first optical axis and the second optical axis are perpendicular to a bus of the cylinder to be detected; the emission position of the first sub-monochromatic parallel light beam on the first optical axis is the same as the emission position of the second sub-monochromatic parallel light beam on the second optical axis; the first diffracted intensity pattern comprises the first sub-intensity pattern and the third sub-intensity pattern; the second diffracted light intensity pattern comprises the second sub light intensity pattern and the fourth sub light intensity pattern; the monochromatic parallel beams comprise the first sub-monochromatic parallel beams and the second sub-monochromatic parallel beams;
the cylinder diameter measuring device further comprises:
computer equipment for calculating the distance between the peak point of the light intensity of the first edge in the first sub-intensity map and the first optical axis, the distance between the peak point of the intensity of the second edge and the second optical axis in the third sub-intensity map, and the distance between the first optical axis and the second optical axis, obtaining the distance between the light intensity peak points of the diameter edge of the cylinder to be measured in the first diffraction light intensity graph, and according to the distance between the light intensity peak point of the first edge in the second sub-light intensity graph and the first optical axis, the distance between the peak point of the intensity of the second edge and the second optical axis in the fourth sub-intensity map, and the distance between the first optical axis and the second optical axis, and acquiring the distance between light intensity peak points of the diameter edge of the cylinder to be detected in the second diffraction light intensity graph; and acquiring the diameter of the cylinder to be detected according to the wavelength of the monochromatic parallel light beams, the distance between the two positions, and the distance between the light intensity peak points of the diameter edge of the cylinder to be detected in the first diffraction light intensity graph and the second diffraction light intensity graph.
5. The cylinder diameter measuring device according to claim 4, wherein the monochromatic parallel beam module includes a monochromatic point light source and a collimating lens.
6. The cylinder diameter measuring device according to claim 4, wherein the first monochromatic parallel beam sub-module comprises a monochromatic point light source and a collimating lens; the second monochromatic parallel beam submodule comprises a monochromatic point light source and a collimating lens.
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