CN117516415A

CN117516415A - Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection method, device and system

Info

Publication number: CN117516415A
Application number: CN202410017731.0A
Authority: CN
Inventors: 陶春
Original assignee: Nanjing Simite Optical Instruments Co ltd
Current assignee: Nanjing Simite Optical Instruments Co ltd
Priority date: 2024-01-05
Filing date: 2024-01-05
Publication date: 2024-02-06
Anticipated expiration: 2044-01-05
Also published as: CN117516415B

Abstract

The embodiment of the invention provides a method, a device and a system for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map, wherein the method comprises the following steps: acquiring a knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates; acquiring a knife-edge shadow map corresponding to each of a plurality of Y-axis knife-edge coordinates; for a knife-edge shadow map corresponding to each X-axis/Y-axis knife-edge coordinate, positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map, taking the plurality of pixel coordinates as a plurality of index positions of an X-axis/Y-axis cutting distribution matrix, taking the numerical value of the X-axis/Y-axis knife-edge coordinate as a matrix element, and writing the numerical value into the plurality of index positions in the X-axis/Y-axis cutting distribution matrix; applying a Zernike fitting differential phase fitting technology to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of the surface shape to be measured; judging whether the surface shape to be measured meets the precision requirement according to the surface shape matrix of the surface shape to be measured.

Description

Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection method, device and system

Technical Field

The invention relates to the technical field of optical precision measurement, in particular to a method, a device and a system for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map.

Background

The knife-edge shadow instrument is a high-precision optical detection instrument and is widely applied to the field of optical precision machining. Particularly, in the process of processing large-caliber aspheric surfaces and off-axis aspheric surfaces, the dynamic range is large, the reliability is high, and the device is often used as detection equipment in the rough polishing stage of the mirror surface. In addition, the knife edge shadow instrument has small volume and convenient carrying, and the light path is erected in a processing environment or an outfield environment, so the knife edge shadow instrument can also be used as a system image quality detection device. In summary, the knife-edge shadow instrument works as a spherical wave interferometer, but has a larger dynamic range than the spherical wave interferometer. At present, a knife edge shadow instrument is a qualitative detection technology.

In carrying out the present invention, the applicant has found that at least the following problems exist in the prior art:

the surface shape quality detection based on the knife edge shadow instrument in the prior art cannot quantitatively detect the surface shape quality and has low surface shape universality.

Disclosure of Invention

The embodiment of the invention provides a method, a device and a system for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map, which are also a method, a device and a system for detecting surface shape quality based on Zernike fitting, and also a method, a device and a system for detecting surface shape quality, and solve the problems that the surface shape quality detection based on a knife-edge shadow instrument in the prior art cannot be quantitatively detected and the surface shape universality is low.

In order to achieve the above objective, in a first aspect, an embodiment of the present invention provides a method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map, including:

acquiring a knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates, wherein the X-axis knife-edge coordinates are uniformly divided into light spots in the X-axis direction;

acquiring a knife-edge shadow map corresponding to each of a plurality of Y-axis knife-edge coordinates, wherein the plurality of Y-axis knife-edge coordinates equally divide light spots in the Y-axis direction;

positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in each X-axis knife-edge shadow map, taking the pixel coordinates as a plurality of index positions of an X-axis cutting distribution matrix, taking the numerical value of the X-axis knife-edge coordinate as a matrix element, and writing the numerical value into the index positions in the X-axis cutting distribution matrix;

for a knife-edge shadow map corresponding to each Y-axis knife-edge coordinate, positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map, taking the pixel coordinates as a plurality of index positions of a Y-axis cutting distribution matrix, taking the numerical value of the Y-axis knife-edge coordinate as a matrix element, and writing the numerical value into the index positions in the Y-axis cutting distribution matrix;

Applying a Zernike fitting differential phase fitting technology to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of the surface shape to be measured;

judging whether the surface shape to be measured meets the precision requirement according to the surface shape matrix of the surface shape to be measured;

wherein the light spot is a pinhole image formed at the knife edge of the knife edge shadow instrument on the surface to be measured; the X-axis knife edge coordinate is the X-axis coordinate of the knife edge on the knife edge shadow instrument; the Y-axis knife edge coordinate is the Y-axis coordinate of the knife edge on the knife edge shadow instrument; the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix are matrixes which initialize all matrix elements into invalid values in advance; the elements in the surface shape matrix of the surface shape to be measured represent surface shape deviation values of the surface shape to be measured relative to a preset standard surface shape.

In a second aspect, an embodiment of the present invention provides a Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device, including:

an X-axis knife edge shadow map obtaining unit, which is used for obtaining knife edge shadow maps corresponding to a plurality of X-axis knife edge coordinates respectively, wherein the X-axis knife edge coordinates are equally divided into light spots in the X-axis direction;

the Y-axis knife edge shadow map acquisition unit is used for acquiring knife edge shadow maps corresponding to a plurality of Y-axis knife edge coordinates respectively, wherein the plurality of Y-axis knife edge coordinates are equally divided into light spots in the Y-axis direction;

An X-axis cutting distribution matrix obtaining unit, configured to, for a knife-edge shadow map corresponding to each X-axis knife-edge coordinate, locate a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map, take the plurality of pixel coordinates as a plurality of index positions of an X-axis cutting distribution matrix, and write a numerical value of the X-axis knife-edge coordinate as a matrix element into the plurality of index positions in the X-axis cutting distribution matrix;

the Y-axis cutting distribution matrix acquisition unit is used for positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in each Y-axis knife-edge coordinate for the knife-edge shadow graph, taking the pixel coordinates as a plurality of index positions of a Y-axis cutting distribution matrix, taking the numerical value of the Y-axis knife-edge coordinate as a matrix element, and writing the numerical value into the index positions in the Y-axis cutting distribution matrix;

the surface shape matrix determining unit is used for applying a Zernike fitting differential phase fitting technology to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of a surface shape to be measured;

the surface shape accuracy judging unit is used for judging whether the surface shape to be detected meets the accuracy requirement according to the surface shape matrix of the surface shape to be detected;

In a third aspect, an embodiment of the present invention provides a Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection system, including: the device comprises a knife-edge shadow instrument, a Zernike fitting knife-edge shadow figure wavefront reconstruction surface shape detection device and a knife-edge shadow figure acquisition device, wherein the Zernike fitting knife-edge shadow figure wavefront reconstruction surface shape detection device is used for detecting the front surface shape of the knife-edge shadow figure;

the knife-edge shadow instrument is used for moving the knife-edge in the X-axis direction so as to form a knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates in the X-axis direction for the surface to be measured, and moving the knife-edge in the Y-axis direction so as to form a knife-edge shadow map corresponding to each of a plurality of Y-axis knife-edge coordinates in the Y-axis direction for the surface to be measured;

the knife-edge shadow map acquisition device is used for acquiring knife-edge shadow maps corresponding to the X-axis knife-edge coordinates and knife-edge shadow maps corresponding to the Y-axis knife-edge coordinates respectively during the movement of the knife edge of the knife-edge shadow instrument;

The Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection device is used for generating a surface shape matrix of a surface shape to be detected according to the knife-edge shadow maps corresponding to the X-axis knife-edge coordinates and the knife-edge shadow maps corresponding to the Y-axis knife-edge coordinates, and judging whether the surface shape to be detected meets the precision requirement according to the surface shape matrix of the surface shape to be detected.

The technical scheme has the following beneficial effects: the method comprises the steps of obtaining a plurality of knife-edge shadow maps in the X-axis and Y-axis directions, thereby comprehensively obtaining the transverse and longitudinal data of the surface shape, obtaining a surface shape matrix of the surface shape to be measured according to a knife-edge shadow image wavefront calculation method of Zernike fitting differential phase fitting technology based on the obtained knife-edge shadow maps in the X-axis and Y-axis directions, judging the quality precision of the surface shape to be measured according to the obtained surface shape matrix, providing quantized surface shape data, solving the problem of knife-edge shadow map wavefront calculation, and promoting the wide application of the knife-edge shadow instrument in the optical rough machining stage and the finish machining stage. The Zernike fitting knife-edge shadow wavefront calculation method is adopted, the type of the reflecting surface is not limited, and the universality is high. Can be used in combination with most digital incision instruments, and the subjective experience limitation is completely eliminated by automatically judging the result. The digital knife edge instrument can be used in rough repair and finish repair, and the application range of the digital knife edge instrument is increased.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection device according to one embodiment of the present invention;

FIG. 3 is a schematic diagram of a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection system according to one embodiment of the present invention;

FIG. 4 is a schematic top layout view of a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection system according to one embodiment of the present invention;

FIG. 5 is a knife-edge shadow view of a knife-edge at X-axis start coordinates in accordance with one embodiment of the present invention;

FIG. 6 is a knife-edge shadow view of a knife-edge at an X-axis end point coordinate in accordance with one embodiment of the present invention;

FIG. 7 is a knife-edge shadow view of a knife-edge at Y-axis start coordinates in accordance with one embodiment of the present invention;

FIG. 8 is a knife-edge shadow view of a knife-edge at the Y-axis end point coordinate in accordance with one embodiment of the present invention;

FIG. 9 is a knife-edge shadow view of a knife-edge at an X-axis knife-edge coordinate in accordance with one embodiment of the invention;

FIG. 10 is a knife-edge shadow view of a knife-edge at a certain Y-axis knife-edge coordinate in accordance with one embodiment of the invention;

FIG. 11 is an X-axis cut distribution plot from an X-axis cut distribution matrix plot in accordance with one embodiment of the present invention;

FIG. 12 is a Y-axis cut distribution plot from a Y-axis cut distribution matrix plot in accordance with one embodiment of the present invention;

FIG. 13 is a graph of the numerical values of coefficients plotted in a Zernike coefficient matrix according to one embodiment of the present invention;

FIG. 14 is a graph corresponding to a face matrix according to an embodiment of the present invention.

The reference numerals are expressed as: 30. a knife edge shadow instrument; 31. the Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device; 32. the knife edge shadow map acquisition device; 33. surface shape to be measured; 301. a knife edge; 302. a light source system; 303. a beam splitter; 304. an XY plane; 321. the photographing direction.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The inventor finds that the optical element, the optical system or the optical material in the prior art has defects at any part, and the judgment of the direction and the severity of the defects depends on the subjective experience of a detector, so that the surface shape quality of the detected optical element cannot be quantitatively given; the factor makes the processing personnel unable to obtain detection data through the knife edge shadow instrument in the rough polishing stage of the optical piece, so that the quick processing cannot be realized by using the digital processing equipment; the detection result depends on subjective judgment of a detector, so that the instrument test precision is low, and the application of the knife-edge shadow instrument in the precise detection stage of optical processing is limited. The inventor also finds that the digitization and the intellectualization of the knife-edge shadow instrument in the prior art are mostly aimed at a specific reflecting surface form in terms of algorithms, and have low universality.

In view of the above problems, as shown in fig. 1, an embodiment of the present invention provides a method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map, including:

s10, acquiring a knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates, wherein the X-axis knife-edge coordinates are equally divided into light spots in the X-axis direction;

s11, acquiring knife-edge shadow maps corresponding to a plurality of Y-axis knife-edge coordinates respectively, wherein the plurality of Y-axis knife-edge coordinates equally divide light spots in the Y-axis direction;

Step S12, positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in each X-axis knife-edge shadow graph, taking the pixel coordinates as a plurality of index positions of an X-axis cutting distribution matrix, taking the numerical value of the X-axis knife-edge coordinate as a matrix element, and writing the numerical value into the index positions in the X-axis cutting distribution matrix;

step S13, positioning a plurality of pixel coordinates corresponding to knife-edge shadow boundaries in a knife-edge shadow map according to a knife-edge shadow map corresponding to each Y-axis knife-edge coordinate, taking the pixel coordinates as a plurality of index positions of a Y-axis cutting distribution matrix, taking the numerical value of the Y-axis knife-edge coordinate as a matrix element, and writing the numerical value into the index positions in the Y-axis cutting distribution matrix;

s14, applying a Zernike fitting differential phase fitting technology to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of the surface shape to be measured;

step S15, judging whether the surface shape to be measured meets the precision requirement according to the surface shape matrix of the surface shape to be measured;

wherein the light spot is a pinhole image formed at the knife edge of the knife edge shadow instrument on the surface to be measured; the X-axis knife edge coordinate is the X-axis coordinate of the knife edge on the knife edge shadow instrument; the Y-axis knife edge coordinate is the Y-axis coordinate of the knife edge on the knife edge shadow instrument; the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix are matrixes which initialize all matrix elements into invalid values in advance; the elements in the surface shape matrix of the surface shape to be measured represent surface shape deviation values of the surface shape to be measured relative to a preset standard surface shape. Preferably, the dimension of the X-axis cutting distribution matrix is the same as the pixel dimension of the knife-edge shadow map corresponding to the X-axis knife-edge coordinate, and the dimension of the Y-axis cutting distribution matrix is the same as the pixel dimension of the knife-edge shadow map corresponding to the Y-axis knife-edge coordinate.

In some embodiments, fig. 4 is a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection system, which shows an optical path diagram of a knife-edge shadow instrument 30, wherein a light source system 302, a beam splitter 303, a measured mirror (surface shape 33 to be measured), a knife edge 301, and an image acquisition and processing system (including a knife-edge shadow acquisition device 32 and a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection device 31); the test light is emitted from the light source system 302, and reflected to a measured mirror (e.g., a spherical mirror to be measured) through the spectroscope 303. The detected mirror returns the light beam, and focuses the light beam to the position of the knife edge 301 through the spectroscope 303, in fig. 4, the XY plane 304 is a plane perpendicular to the photographing direction 321 of the knife edge shadow image collecting device 32 passing through the knife edge 301, the X axis direction is a horizontal direction in the XY plane 304, and the Y axis direction is a vertical direction in the XY plane 304. The knife edge 301 is cut along the X-axis direction and the Y-axis direction, the formed knife edge shadow map is collected by a knife edge shadow map collecting device 32 (an image collecting system), a Zernike fitting knife edge shadow map wavefront reconstruction surface shape detecting device 31 obtains the knife edge shadow map and generates a surface shape matrix of a surface shape to be detected, and whether the surface shape to be detected meets the precision requirement is judged according to the surface shape matrix of the surface shape to be detected. The knife-edge shadow instrument 30 can be manually adjusted manually or the knife-edge shadow instrument 30 can be automatically controlled (preferably, the knife-edge shadow instrument 30 can be automatically controlled to move along the X-axis direction or the Y-axis direction by the Zernike fitting knife-edge shadow-image wavefront reconstruction surface detection device 31), when the knife-edge is at each X-axis knife-edge coordinate, the knife-edge shadow image corresponding to the X-axis knife-edge coordinate in the field of view can be acquired by the knife-edge shadow-image acquisition device 32, and similarly, when the knife-edge is at each Y-axis knife-edge coordinate, the knife-edge shadow image corresponding to the Y-axis knife-edge coordinate in the field of view can be acquired by the knife-edge shadow-image acquisition device 32, and the knife-edge shadow images corresponding to the plurality of X-axis knife-edge coordinates acquired by the knife-edge shadow-image acquisition device 32 and the knife-edge wavefront reconstruction surface detection device 31 can be input to the Zernike by a manual input mode or an automatic transmission mode. Wherein, the invalid values for initializing the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix can be set to values which cannot occur in the Y-axis knife-edge coordinate or the X-axis knife-edge coordinate in the detection process.

The embodiment of the invention has the following technical effects: the method comprises the steps of obtaining a plurality of knife-edge shadow maps in the X-axis and Y-axis directions, thereby comprehensively obtaining the transverse and longitudinal data of the surface shape, obtaining a surface shape matrix of the surface shape to be measured according to a knife-edge shadow image wavefront calculation method of Zernike fitting differential phase fitting technology based on the obtained knife-edge shadow maps in the X-axis and Y-axis directions, judging the quality precision of the surface shape to be measured according to the obtained surface shape matrix, being universal for various surface shapes, being capable of carrying out surface shape deviation larger optical piece measurement and also carrying out surface shape deviation smaller optical piece measurement, providing quantized surface shape data, solving the problem of calculating the wave fronts of the knife-edge shadow maps, and promoting the wide application of the knife-edge shadow instrument in an optical rough machining stage and a finish machining stage. The Zernike fitting knife-edge shadow wavefront calculation method is adopted, the type of the reflecting surface is not limited, and the universality is high. Can be used in combination with most digital incision instruments, and the subjective experience limitation is completely eliminated by automatically judging the result. The digital knife edge instrument can be used in rough repair and finish repair, and the application range of the digital knife edge instrument is increased.

Further, the obtaining a knife-edge shadow map corresponding to each of the plurality of X-axis knife-edge coordinates, where the plurality of X-axis knife-edge coordinates equally divide the light spot in the X-axis direction includes:

controlling the knife edge to move along the X-axis direction, and recording X-axis starting point coordinates of the knife edge shadow just formed in the view field and X-axis end point coordinates of all cut light rays in the view field; the X-axis starting point coordinates and the X-axis ending point coordinates correspond to left and right boundaries of the light spots in the X-axis direction;

calculating the distance from the X-axis starting point coordinate to the X-axis ending point coordinate, and dividing the obtained distance by the preset X-axis stepping times to obtain an X-axis stepping distance;

controlling the knife edge to start from the X-axis starting point coordinate along the X-axis direction, taking the X-axis stepping distance as a step length to step until the knife edge reaches the X-axis end point coordinate, stopping stepping, and collecting a knife edge shadow map of the knife edge at each X-axis knife edge coordinate as a knife edge shadow map corresponding to the X-axis knife edge coordinate;

wherein the plurality of X-axis knife edge coordinates includes: x-axis start coordinates, X-axis start coordinates+x-axis step distances, X-axis start coordinates+2×x-axis step distances, X-axis start coordinates+3×x-axis step distances, &..the X-axis start coordinates+i×x-axis step distances, &..the X-axis end coordinates, wherein i is an integer of 0 or more and equal to or less than a preset X-axis step number.

Preferably, after the optical path is built, cutting the knife edge along the X direction and recording the cutting position to obtain X cutting range of-90-400 mu m (micrometers), namely X-axis starting point coordinates are more than or equal to-90 mu m, and X-axis end point coordinates are less than or equal to 400 mu m; setting the cutting step length (X-axis stepping distance) to be 10 mu m;

in some embodiments, a digital knife edge instrument is adopted to measure the mirror surface to be measured (surface shape to be measured), a one-dimensional guide rail for installing a knife edge is controlled to cut from left to right (along the X-axis direction), and the position of a knife edge shadow map which is just formed is recordedAnd the position in the field of view where the light is totally cut +.>For example, FIG. 5 shows the knife edge in position +.>The knife-edge shadow map in the time can be seen that the knife-edge shadow appears at the boundary of the upper left corner of FIG. 5, and FIG. 6 shows the knife-edge at the position +.>The knife-edge shadow map in this case shows that most of the shading in fig. 6 is a bright area left only at the boundary of the upper right corner. The knife edge cutting step length (X-axis stepping distance) can be calculated according to the formula (1) from the cutting length (the distance from the X-axis starting point coordinate to the X-axis ending point coordinate)>：

（1）

Wherein, N is the preset X-axis stepping times, the larger N is, the smaller the X-axis stepping distance is, the more knife-edge shadow pictures are obtained, the more accurate the detection result is, and preferably N is more than 35;

The knife edge is moved to the left again, the focal plane is cut from left to right under the control of an image acquisition and processing system (such as the Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection device 31 in figure 4), and the guide rail is moved to the position、、/>、……/>(i.e., the plurality of X-axis knife edge coordinates includes X-axis start point coordinates, X-axis start point coordinates+x-axis step distances, X-axis start point coordinates+2X-axis step distances, X-axis start point coordinates+3X-axis step distances,) X-axis start point coordinates+i X-axis step distances,) X-axis end point coordinates, where i is an integer greater than or equal to 0 and less than or equal to a preset X-axis step number) forming an X-direction knife edge shadow map as Px ₀ 、Px ₁ 、Px ₂ ……Px _N (i.e., a plurality of knife-edge shadow maps corresponding to the X-axis knife-edge coordinates respectively); when the surface shape to be detected has no deviation, a pinhole image formed at the ideal focal point position is a light spot, and the size of the light spot is far smaller than the stepping precision of the knife edge, so that the knife edge does not shade the light spot or completely shade the light spot as long as the knife edge moves the position at the focal point in a stepping way, and the obtained shadow map is either totally bright or totally dark; when the surface shape to be detected has deviation, a light spot is formed at the ideal focal position instead of a light spot, the light spot can be in various shapes, the size of the light spot in the X-axis direction and the Y-axis direction is larger than the stepping precision of the knife edge, so that when the knife edge position is outside the light spot, the obtained shadow map is full bright, when the knife edge position completely shields the light spot, the obtained shadow map of the knife edge is full dark, when the knife edge moves to a certain X-axis knife edge coordinate position of the middle position of the light spot, the knife edge shadow map shown in fig. 9 is obtained, the middle part of fig. 9 is mostly shadow, the upper right corner is provided with a crescent bright part, the lower left corner is provided with a small irregular bright part, and the quality problem of the surface shape area to be detected is indicated.

The embodiment of the invention has the following technical effects: the sampling density of the X-direction knife edge shadow map can be adjusted as required by setting the preset X-axis stepping times, and more detailed surface shape data can be obtained by sampling at the positions of a plurality of X-axis knife edge coordinates, so that more accurate surface shape matrixes can be obtained.

Further, the obtaining a knife-edge shadow map corresponding to each of the plurality of Y-axis knife-edge coordinates, where the plurality of Y-axis knife-edge coordinates equally divide the light spot in the Y-axis direction includes:

controlling the knife edge to move along the Y-axis direction, and recording the Y-axis starting point coordinate of the knife edge shadow just formed in the view field and the Y-axis end point coordinate of the light ray in the view field when all the light rays are cut; the Y-axis starting point coordinates and the Y-axis ending point coordinates correspond to left and right boundaries of the light spots in the Y-axis direction;

calculating the distance from the Y-axis starting point coordinate to the Y-axis ending point coordinate, and dividing the obtained distance by the preset Y-axis stepping times to obtain a Y-axis stepping distance;

controlling the knife edge to start from the Y-axis starting point coordinate along the Y-axis direction, taking the Y-axis stepping distance as a step length to step until the knife edge reaches the Y-axis end point coordinate, stopping stepping, and collecting a knife edge shadow map of the knife edge at each Y-axis knife edge coordinate as a knife edge shadow map corresponding to the Y-axis knife edge coordinate;

Wherein the plurality of Y-axis knife edge coordinates comprises: y-axis start coordinates, Y-axis start coordinates+y-axis step distances, Y-axis start coordinates+2×y-axis step distances, Y-axis start coordinates+3×y-axis step distances, &..the Y-axis start coordinates+j×y-axis step distances, &..the Y-axis end coordinates, where j is an integer of 0 or more and equal to or less than a preset Y-axis step number.

Preferably, after the light path is built, cutting the knife edge along the Y direction and recording the cutting position to obtain Y cutting range of-80-270 μm (micrometers), namely Y-axis starting point coordinates are more than or equal to-80 μm, and Y-axis end point coordinates are less than or equal to 270 μm; setting the cutting step length (Y-axis stepping distance) to be 10 mu m;

in some embodiments, a digital knife edge instrument is used for measuring a mirror surface to be measured (surface shape to be measured), a one-dimensional guide rail for installing a knife edge is controlled to cut from top to bottom (along the Y-axis direction), and the position of a knife edge shadow map which is just formed is recordedAnd the position in the field of view where the light is totally cut +.>The method comprises the steps of carrying out a first treatment on the surface of the For example, FIG. 7 shows the knife edge in position +.>The knife-edge shadow map in the time can be seen that the knife-edge shadow appears at the boundary of the upper right corner of FIG. 7, and FIG. 8 shows the knife-edge at the position +.>The knife-edge shadow map in this case shows that most of the shading in fig. 8 is the bright area remaining only on the lower boundary. The knife edge cutting step length (Y-axis stepping distance) can be calculated according to the formula (2) from the cutting length (the distance from the Y-axis starting point coordinate to the Y-axis ending point coordinate) >：

（2）

Wherein M is the preset Y-axis stepping times, the larger M is, the smaller Y-axis stepping distance is, the more knife-edge shadow maps are obtained, the more accurate the detection result is, and preferably M is more than 35;

the knife edge is moved to the upper side again, the focal plane is cut from top to bottom under the control of an image acquisition and processing system (such as a Zernike fitting knife-edge shadow wave front reconstruction surface shape detection device 31 in figure 4), and the guide rail is moved to a position、、/>、……/>(i.e., the plurality of Y-axis knife edge coordinates includes a Y-axis start point coordinate, a Y-axis start point coordinate + Y-axis step distance, a Y-axis start point coordinate +2 x Y-axis step distance, a Y-axis start point coordinate +3 x Y-axis step distance,) a Y-axis start point coordinate + j x Y-axis step distance,) a Y-axis end point coordinate, where j is an integer greater than or equal to 0 and less than or equal to a preset Y-axis step number) form a Y-direction knife edge shadow map as Py ₀ 、Py ₁ 、Py ₂ ……Py _M (i.e., the knife-edge shadow diagrams corresponding to the plurality of Y-axis knife-edge coordinates) are shown in fig. 10, and the knife-edge shadow diagram obtained at a certain Y-axis knife-edge coordinate in the middle position is mostly bright, and the small part is shadow in fig. 10, so that the quality problem of the surface shape area to be measured is illustrated.

The embodiment of the invention has the following technical effects: the sampling density of the Y-direction knife edge shadow map can be adjusted as required by setting the preset Y-axis stepping times, and more detailed surface shape data can be obtained by sampling at the positions of the plurality of Y-axis knife edge coordinates, so that more accurate surface shape matrixes can be obtained.

Further, the positioning, for each of the X-axis knife-edge shadow maps, a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map includes:

calculating the average value of the light intensity of the knife-edge shadow map corresponding to each X-axis knife-edge coordinate;

and traversing all pixels in the knife-edge shadow map, finding out pixels with the distance value from the light intensity value to the light intensity average value smaller than a preset light intensity threshold value, and taking the pixel coordinates of the found pixels in the knife-edge shadow map as the pixel coordinates corresponding to the knife-edge shadow boundary in the knife-edge shadow map.

There are many border processing algorithms in the prior art, such as the candy algorithm (one edge detection algorithm) and the sobel algorithm (another edge detection algorithm), but most of these algorithms are directed to sharp-border images. The inventor finds that the knife edge boundary of the knife edge shadow map does not belong to an image with sharp boundary, and is characterized in that the change from the gray value (light intensity value) of the image to the larger value of the image is linear change instead of step change, so that a better effect cannot be obtained by using an image processing algorithm. Some researchers in the prior art also research a knife edge shadow boundary extraction method, which is mainly used for detecting that a detected piece is an aspheric surface, and the inventor considers that the method lacks universality. In the prior art, a scholars also use a linear fitting method to extract the boundary, and the inventor finds that the fitting of the method needs reliable data on two sides of the boundary in a knife-edge shadow map, so that the method is actually aimed at the situation that the surface shape deviation of a mirror surface to be measured (the surface shape to be measured) is smaller, and the boundary error at the edge of an image is larger.

Based on the above findings, the embodiment of the invention is provided, overcomes the above limitations, does not need fitting, does not limit the object type of the mirror surface to be measured (surface shape to be measured), and can be suitable for larger surface shape errors and smaller surface shape errors. Through simulation comparison, the embodiment of the invention shows very high detection precision and reliability in knife edge shadow detection. The method comprises the following specific steps:

in some embodiments, the following operation is performed on the knife-edge shadow map corresponding to each X-axis knife-edge coordinate in the X-axis direction, so as to obtain an X-axis cutting distribution matrix Ex:

(a) For the coordinate position of the X-axis knife edgeKnife-edge shadow graph Pxi at position of light intensity average value +.>；

(b) Intensity of each pixel traversed in the knife-edge shadow map Pxi(wherein k represents the kth pixel), find to satisfy +.>Coordinates (Xk, yk) of the condition, and assigning index positions corresponding to (Xk, yk) in the X-axis cut distribution matrix Ex as +.>I.e., ex (Xk, yk) = = -x>；

(c) Traversing the knife-edge shadow map corresponding to each X-axis knife-edge coordinate position, and repeating the steps (a) - (b) to obtain a complete X-axis cutting distribution matrix Ex. As shown in fig. 11, the X-axis cut distribution matrix Ex is drawn as an X-axis cut distribution map, so that the data distribution in the X-axis cut distribution matrix Ex can be more intuitively observed.

The embodiment of the invention has the following technical effects: the embodiment of the invention provides a method for detecting surface shape quality by reconstructing a knife-edge shadow map wavefront based on Zernike fitting, which can be used in combination with most knife-edge instruments (knife-edge shadow instruments). The method adopts a knife edge position positioning technology based on light intensity information and a Zernike fitting differential phase fitting technology to realize wave front reconstruction in a knife edge shadow map. The method does not make any assumption on the surface shape to be detected, so that the method is suitable for detecting various reflection surfaces or system wave aberration. The method is suitable for the rough polishing stage and the finishing stage of the mirror surface, and expands the application range of the knife edge instrument.

Further, the positioning the plurality of pixel coordinates corresponding to the edge shadow boundary in the edge shadow map for the edge shadow map corresponding to each Y-axis edge coordinate includes:

calculating the average value of the light intensity of the knife-edge shadow map corresponding to the Y-axis knife-edge coordinate;

There are many boundary processing algorithms in the prior art, such as candy algorithm and sobel algorithm. But most of these algorithms are directed to sharp-boundary images. The inventor finds that the knife edge boundary of the knife edge shadow map does not belong to an image with sharp boundary, and is characterized in that the change from the gray value of the image to the larger value of the image is linear change instead of step change, so that a better effect cannot be obtained by using an image processing algorithm. Some researchers in the prior art also research a knife edge shadow boundary extraction method, which is mainly used for detecting that a detected piece is an aspheric surface, and the inventor considers that the method lacks universality. In the prior art, a scholars also use a linear fitting method to extract the boundary, and the inventor finds that the fitting of the method needs reliable data on two sides of the boundary in a knife-edge shadow map, so that the method is actually aimed at the situation that the surface shape deviation of a mirror surface to be measured (the surface shape to be measured) is smaller, and the boundary error at the edge of an image is larger.

In some embodiments, the following operations are performed on the knife-edge shadow map corresponding to each Y-axis knife-edge coordinate in the Y-axis direction, so as to obtain a Y-axis cutting distribution matrix Ey:

(a) For Y-axis knife edge coordinate positionKnife-edge shadow graph Pyj at position of light intensity average value +.>；

(b) Intensity of each pixel traversed in the knife-edge shadow map Pyj(wherein k represents the kth pixel), find to satisfy +.>Coordinates (Xk, yk) of the condition, and assigning index positions corresponding to (Xk, yk) in the Y-axis cut distribution matrix Ey as +.>I.e. Ey (Xk, yk) = = -> ；

(c) Traversing the knife-edge shadow map corresponding to each Y-axis knife-edge coordinate position, repeating the steps (a) - (b) to obtain a complete Y-axis cutting distribution matrix Ey, and drawing the Y-axis cutting distribution matrix Ey into a Y-axis cutting distribution map as shown in fig. 12, so that the data distribution condition in the Y-axis cutting distribution matrix Ey can be more intuitively observed.

Further, the applying a Zernike fitting differential phase fitting technique to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of the surface shape to be measured includes:

constructing a differential wavefront coefficient matrix by using a Zernike polynomial (Zernike polynomial);

aiming at the X-axis cutting distribution matrix, the Y-axis cutting distribution matrix and the differential wavefront coefficient matrix, a least square method is used to obtain a Zernike coefficient matrix of the surface shape to be detected;

and constructing a surface shape matrix of the surface shape to be detected according to the Zernike coefficient matrix and the Zernike polynomial of the surface shape to be detected.

In some embodiments, the differential wavefront coefficient matrix is constructed using Zernike polynomials:

（3）

wherein the method comprises the steps ofRepresenting the value of the j-th term Zernike polynomial at the i-th sampling point after the x is biased; wherein the method comprises the steps ofRepresenting the value of the j-th term Zernike polynomial at the i-th sampling point after carrying out bias derivative on y; v is the number of Zernike polynomials that participate in the calculation;

obtaining a Zernike coefficient matrix S of the surface shape to be measured by using a least square method according to a formula (4):

（4）

wherein the method comprises the steps ofR is the equivalent curvature radius of the surface shape to be measured. />And->The X-axis cutting distribution matrix and the Y-axis cutting distribution matrix are respectively arranged in a vector form; the Zernike coefficient matrix S stores the values of the Zernike coefficients, as shown in fig. 13, which illustrates the values of the coefficients in the Zernike coefficient matrix S obtained in an embodiment, the ordinate of fig. 13 is the values of the coefficients, and the abscissa is the sequence number of the coefficients in the Zernike coefficient matrix S, for example, the coefficients (elements) in the Zernike coefficient matrix S may be numbered according to the line direction preference to obtain the sequence numbers corresponding to the abscissa.

And reconstructing a surface shape matrix W of the surface shape to be measured by using the calculated Zernike coefficient matrix S and the Zernike polynomial according to the formula (5):

（5）

as shown in fig. 14, each element in the obtained surface shape matrix W is used as a pixel in a picture, so that the surface shape matrix W is displayed as the picture shown in fig. 14, and the quality of the surface shape to be measured can be more intuitively observed from the picture. If there is a significant difference in the gray values of the pixels on the picture, it can be intuitively observed that there is a significant deviation of the surface shape to be measured relative to the standard surface shape, whereas, in particular, in the case of fig. 14, it can be seen that the gray values in fig. 14 are significantly deviated, so that the surface shape to be measured corresponding to fig. 14 does not meet the accuracy requirement.

The Zernike polynomials have a certain correspondence with the primary aberrations and are easily linked to the Seidel aberration functions commonly used in optical design, which is also the reason why Zernike polynomials are commonly used in optical aberration analysis.

The Zernike coefficients are related to aberrations as shown in table 1 below:

TABLE 1 relationship table of Zernike coefficients and aberration

The aberrations of an optical system are typically described using a form of power series expansion. Since the form of the zernike polynomials and the aberration polynomials observed in optical detection are identical, it is often used to describe wavefront characteristics.

In a polar coordinate system, the Zernike polynomials are expressed as:

（6）

wherein,；/>is a term related to radial only, specifically equation (7); />Is a term related to only the argument, specifically equation (8); n is the order of the polynomial; m is a frequency number; />The value range is 0,1]；/>The value range is +.>；/>N and +.>Parity is the same->，/>Always even.

（7）

（8）

The embodiment of the invention has the following technical effects: the Zernike fitting knife-edge shadow wavefront calculation method is adopted, the type of the reflecting surface is not limited, and the universality is high. Can be used in combination with most digital incision instruments, and the subjective experience limitation is completely eliminated by automatically judging the result. The digital knife edge instrument can be used in rough repair and finish repair, and the application range of the digital knife edge instrument is increased.

Further, the determining whether the surface shape to be measured meets the precision requirement according to the surface shape matrix of the surface shape to be measured includes:

judging whether each element in the surface shape matrix of the surface shape to be detected is smaller than a preset precision threshold value or not;

if all elements in the surface shape matrix of the surface shape to be detected are judged to be smaller than a preset precision threshold, the surface shape to be detected meets the precision requirement, otherwise, the surface shape to be detected does not meet the precision requirement.

The embodiment of the invention has the following technical effects: can be used in combination with most digital incision instruments, and the subjective experience limitation is completely eliminated by automatically judging the result.

In a second aspect, as shown in fig. 2, an embodiment of the present invention provides a Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device, including:

an X-axis knife edge shadow map obtaining unit 200, configured to obtain knife edge shadow maps corresponding to a plurality of X-axis knife edge coordinates, where the plurality of X-axis knife edge coordinates are equally divided into light spots in the X-axis direction;

a Y-axis knife edge shadow map obtaining unit 201, configured to obtain knife edge shadow maps corresponding to a plurality of Y-axis knife edge coordinates, where the plurality of Y-axis knife edge coordinates are equally divided into light spots in a Y-axis direction;

an X-axis cutting distribution matrix obtaining unit 202, configured to locate, for a knife-edge shadow map corresponding to each X-axis knife-edge coordinate, a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map, take the plurality of pixel coordinates as a plurality of index positions of an X-axis cutting distribution matrix, and write a numerical value of the X-axis knife-edge coordinate as a matrix element into the plurality of index positions in the X-axis cutting distribution matrix;

A Y-axis cutting distribution matrix obtaining unit 203, configured to locate, for each knife-edge shadow map corresponding to a knife-edge shadow boundary in the knife-edge shadow map, a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map as a plurality of index positions of a Y-axis cutting distribution matrix, and write a numerical value of the Y-axis knife-edge coordinate as a matrix element into the plurality of index positions in the Y-axis cutting distribution matrix;

the surface shape matrix determining unit 204 is configured to apply a Zernike fitting differential phase fitting technique to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of a surface shape to be measured;

a surface shape accuracy judging unit 205, configured to judge whether the surface shape to be measured meets an accuracy requirement according to a surface shape matrix of the surface shape to be measured;

Further, the X-axis knife-edge shadow map obtaining unit 200 includes:

the spot X-axis boundary determining module is used for controlling the knife edge to move along the X-axis direction and recording the X-axis starting point coordinate of the knife edge shadow formed just before in the view field and the X-axis end point coordinate of the light ray cut in the view field; the X-axis starting point coordinates and the X-axis ending point coordinates correspond to left and right boundaries of the light spots in the X-axis direction;

the X-axis stepping distance determining module is used for calculating the distance from the X-axis starting point coordinate to the X-axis ending point coordinate, and dividing the obtained distance by the preset X-axis stepping times to obtain an X-axis stepping distance;

the X-axis knife edge shadow map acquisition module is used for controlling the knife edge to start from the X-axis starting point coordinate along the X-axis direction, taking the X-axis stepping distance as a step length to step until the knife edge reaches the X-axis end point coordinate, stopping stepping, and collecting the knife edge shadow map of the knife edge at each X-axis knife edge coordinate as a knife edge shadow map corresponding to the X-axis knife edge coordinate;

wherein the plurality of X-axis knife edge coordinates includes: x-axis start point coordinates, X-axis start point coordinates+x-axis step distance, X-axis start point coordinates+2×x-axis step distance, X-axis start point coordinates+3×x-axis step distance, &...

Further, the Y-axis knife-edge shadow map obtaining unit 201 includes:

the light spot Y-axis boundary determining module is used for controlling the knife edge to move along the Y-axis direction and recording the Y-axis starting point coordinate of the knife edge shadow formed just before in the view field and the Y-axis end point coordinate of the light ray cut in the view field; the Y-axis starting point coordinates and the Y-axis ending point coordinates correspond to left and right boundaries of the light spots in the Y-axis direction;

the Y-axis stepping distance determining module is used for calculating the distance from the Y-axis starting point coordinate to the Y-axis ending point coordinate, and dividing the obtained distance by the preset Y-axis stepping times to obtain a Y-axis stepping distance;

the Y-axis knife edge shadow map acquisition module is used for controlling the knife edge to start from the Y-axis starting point coordinate along the Y-axis direction, taking the Y-axis stepping distance as a step length to step until the knife edge reaches the Y-axis end point coordinate, stopping stepping, and collecting the knife edge shadow map of the knife edge at each Y-axis knife edge coordinate as a knife edge shadow map corresponding to the Y-axis knife edge coordinate;

wherein the plurality of Y-axis knife edge coordinates comprises: y-axis start coordinates, Y-axis start coordinates+y-axis step distances, Y-axis start coordinates+2 x Y-axis step distances, Y-axis start coordinates+3 x Y-axis step distances, &..the Y-axis start coordinates+j x Y-axis step distances, &..the Y-axis end coordinates, wherein j is equal to or less than a preset Y-axis step number.

Further, the X-axis cutting distribution matrix acquisition unit 202 includes:

the X-axis light intensity tie value determining module is used for calculating the light intensity average value of the knife-edge shadow map corresponding to each X-axis knife-edge coordinate;

the X-axis knife-edge shadow boundary determining module is used for traversing all pixels in the knife-edge shadow map, finding out pixels with the distance value from the light intensity value to the light intensity average value smaller than a preset light intensity threshold value, and taking the pixel coordinates of the found pixels in the knife-edge shadow map as a plurality of pixel coordinates corresponding to the knife-edge shadow boundary in the knife-edge shadow map.

Further, the Y-axis cutting distribution matrix acquisition unit 203 includes:

the Y-axis light intensity tie value determining module is used for calculating the light intensity average value of the knife-edge shadow map corresponding to each Y-axis knife-edge coordinate;

the Y-axis knife-edge shadow boundary determining module is used for traversing all pixels in the knife-edge shadow map, finding out pixels with the distance value from the light intensity value to the light intensity average value smaller than a preset light intensity threshold value, and taking the pixel coordinates of the found pixels in the knife-edge shadow map as a plurality of pixel coordinates corresponding to the knife-edge shadow boundary in the knife-edge shadow map.

Further, the profile matrix determining unit 204 includes:

the differential wavefront coefficient matrix construction module is used for constructing a differential wavefront coefficient matrix by using a Zernike polynomial;

the Zernike coefficient matrix determining module is used for obtaining the Zernike coefficient matrix of the surface shape to be detected by using a least square method aiming at the X-axis cutting distribution matrix, the Y-axis cutting distribution matrix and the differential wavefront coefficient matrix;

the surface shape matrix determining module is used for constructing the surface shape matrix of the surface shape to be detected according to the Zernike coefficient matrix and the Zernike polynomial of the surface shape to be detected.

Further, the surface shape accuracy judging unit 205 is specifically configured to: judging whether each element in the surface shape matrix of the surface shape to be detected is smaller than a preset precision threshold value or not; if all elements in the surface shape matrix of the surface shape to be detected are judged to be smaller than a preset precision threshold, the surface shape to be detected meets the precision requirement, otherwise, the surface shape to be detected does not meet the precision requirement.

The embodiment of the present invention is an embodiment of a device corresponding to the embodiment of the foregoing Zernike-fitted knife-edge shadow map wavefront reconstruction surface shape detection method, and may be understood according to the foregoing Zernike-fitted knife-edge shadow map wavefront reconstruction surface shape detection method embodiment, which is not described herein again.

In a third aspect, as shown in fig. 3, a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection system includes: a knife-edge shadow instrument 30, a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection device (i.e. a surface shape detection device) 31 and a knife-edge shadow acquisition device 32 as described above;

as shown in fig. 3 and 4, the knife-edge shadow instrument 30 is configured to move the knife-edge 301 in the X-axis direction to form a knife-edge shadow map corresponding to each of the plurality of X-axis knife-edge coordinates in the X-axis direction for the surface to be measured, and to move the knife-edge 301 in the Y-axis direction to form a knife-edge shadow map corresponding to each of the plurality of Y-axis knife-edge coordinates in the Y-axis direction for the surface to be measured;

the knife-edge shadow image acquisition device 32 is used for acquiring knife-edge shadow images corresponding to a plurality of X-axis knife-edge coordinates and knife-edge shadow images corresponding to a plurality of Y-axis knife-edge coordinates respectively during the movement of the knife edge 301 by the knife-edge shadow instrument 30;

the Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection device 31 is configured to generate a surface shape matrix of a surface shape 33 to be detected according to the knife-edge shadow maps corresponding to the plurality of X-axis knife-edge coordinates and the knife-edge shadow maps corresponding to the plurality of Y-axis knife-edge coordinates, and determine whether the surface shape 33 to be detected meets the accuracy requirement according to the surface shape matrix of the surface shape 33 to be detected.

The embodiment of the invention is an embodiment formed by the Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection device, and can be understood according to the Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection device, and is not repeated here.

It should be understood that the specific order or hierarchy of steps in the processes disclosed are examples of exemplary approaches. Based on design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate preferred embodiment of this invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. As will be apparent to those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The foregoing description includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, as used in the specification or claims, the term "comprising" is intended to be inclusive in a manner similar to the term "comprising". Furthermore, any use of the term "or" in the specification of the claims is intended to mean "non-exclusive or".

The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection method is characterized by comprising the following steps of:

2. The method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map according to claim 1, wherein the obtaining the knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates includes:

3. The method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map according to claim 1, wherein positioning a plurality of pixel coordinates corresponding to a knife-edge shadow boundary in the knife-edge shadow map for a knife-edge shadow map corresponding to each X-axis knife-edge coordinate comprises:

4. The method for detecting a wavefront reconstruction surface shape of a Zernike fitted knife-edge shadow map according to claim 1, wherein the applying a Zernike fitted differential phase fitting technique to the X-axis cutting distribution matrix and the Y-axis cutting distribution matrix to obtain a surface shape matrix of a surface shape to be detected includes:

constructing a differential wavefront coefficient matrix by using a Zernike polynomial;

5. The Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection method of claim 1, wherein the determining whether the surface shape to be measured meets an accuracy requirement according to the surface shape matrix of the surface shape to be measured comprises:

6. The Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device is characterized by comprising:

7. The Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device of claim 6, wherein the X-axis knife-edge shadow map acquisition unit comprises:

8. The Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device of claim 6, wherein the X-axis cutting distribution matrix acquisition unit comprises:

9. The Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection device of claim 6, wherein the surface shape matrix determination unit comprises:

10. A Zernike fitted knife-edge shadow map wavefront reconstruction surface shape detection system, comprising: a knife-edge shadow instrument (30), a Zernike fitted knife-edge shadow wavefront reconstruction surface shape detection device (31) as claimed in claim 6, and a knife-edge shadow acquisition device (32);

the knife-edge shadow instrument (30) is used for moving the knife-edge (301) in the X-axis direction so as to form a knife-edge shadow map corresponding to each of a plurality of X-axis knife-edge coordinates in the X-axis direction for the surface shape to be measured, and moving the knife-edge (301) in the Y-axis direction so as to form a knife-edge shadow map corresponding to each of a plurality of Y-axis knife-edge coordinates in the Y-axis direction for the surface shape to be measured;

The knife-edge shadow map acquisition device (32) is used for acquiring knife-edge shadow maps corresponding to the X-axis knife-edge coordinates and knife-edge shadow maps corresponding to the Y-axis knife-edge coordinates respectively during the movement of the knife edge (301) of the knife-edge shadow instrument (30);

the Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection device (31) is used for generating a surface shape matrix of a surface shape (33) to be detected according to the knife-edge shadow maps corresponding to the X-axis knife-edge coordinates and the knife-edge shadow maps corresponding to the Y-axis knife-edge coordinates, and judging whether the surface shape (33) to be detected meets the precision requirement according to the surface shape matrix of the surface shape (33) to be detected.