CN106989689B - The sub-aperture stitching detection method of heavy-calibre planar optical elements face shape - Google Patents
The sub-aperture stitching detection method of heavy-calibre planar optical elements face shape Download PDFInfo
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Abstract
The invention proposes a kind of sub-aperture stitching detection technique of heavy-calibre planar optical elements face shape and devices.When measuring optical element using the technology, basic device includes multiple pinhole cameras, planar optical elements, display composition.The bar graph for showing a series of mechanical periodicity of sinusoidal codings over the display by multiple pinhole cameras while acquiring after tested surface reflects.For the interference for avoiding rear surface reflected light, reflection light is calculated in the coordinate of display plane using Power estimation algorithm, and introduce a ray tracing and the method that reference coordinate face is reference is asked to realize the accurate reset of the plane of reference and tested surface, to deduct test macro systematic error.The slope data that polyphaser obtains obtains the slope distribution on tested full aperture using sub-aperture stitching algorithm, and then integrates and obtain the distribution of heavy-calibre planar optical elements face shape.The test device structure of design is simple, and shock resistance is good, and measuring accuracy is high, can provide a kind of new approaches for heavy-calibre planar optical elements on-line checking.
Description
Technical Field
The invention relates to the technical field of optical element surface shape detection by Phase Measurement Deflection (PMD), in particular to a Phase measurement deflection for realizing large-aperture plane optical element surface shape precision detection based on Sub-aperture splicing technology (Sub-aperture splicing).
Background
Interferometric techniques have been a century ago as a viable and commonly used non-contact, high precision surface sensing technique. The reasons for its widespread use are mainly: (1) the high phase mapping relation in the measurement is simple and direct, (2) the measured object is measured by wavelength, so that the high phase mapping relation has high measurement precision. However, when the surface shape of a large-caliber element is measured, the requirement on the environment is very strict, accurate detection can be performed only in a controlled laboratory environment, the precise detection on the online state and the corresponding change process of the element is very difficult, and a compensating mirror or CGH is usually required when a free curve is measured, so that the interferometry is very inflexible and is expensive. Therefore, researchers have studied different methods. One possible idea is to measure the deflection of the beam after it has entered the reflecting surface, and thus to derive the surface shape of the reflecting surface. Methods based on the principle of the deflection technique include a foucault knife edge detection method and a shack-hartmann sensor. A recently proposed method for realizing high-resolution full-field measurement is Phase measurement deflection (Phase measurement deflection), which is based on the principle of grating reflection, and uses Phase shift fringes to replace binary gratings (International Society for Optics and photonics,2004: 366-. Similar to this method, but with a different nomenclature: SCOTS proposed by arizona optical center, which compares the polarization and hartmann measurement methods, and proposes a reverse hartmann optical test method (Software configurable optical test system) (application, opt.2010,49(23), 4404-; other names are structured light reflection, fringe reflection; or directly termed a flexography.
The deflection is easy to implement and is low in cost. It has also been developed to benefit from advances in the prior art, such as computer-controlled display to produce fringes, camera calibration techniques, etc., but is now used for spherical or aspherical element profile sensing with a center of curvature, and small-aperture planar element profile sensing.
When the phase measurement deflection technology is used for measuring the large-caliber plane optical element, three problems exist. (1) The large size of the measured object requires that the display for projecting the stripes is large enough, and the flatness of the display is difficult to ensure, and the self gravity can cause the display to deform.
(2) A standard reference plane mirror is usually selected to eliminate the system error, but if the reset error exists between the measured plane element and the reference plane, the system error between the measured plane element and the reference plane is not constant. (3) If both the front and back surfaces of the dut have fringe reflections, aliasing of the front and back surface reflection fringes occurs. These three problems can seriously affect the test accuracy.
Aiming at the problems in the aspects of the 3 aspects, the method for measuring the surface shape of the large-caliber plane optical element by using a multi-camera acquisition method and a sub-aperture splicing phase measurement deflection technology is provided, so that the use of a large-size display is avoided. By means of a reference surface auxiliary adjusting method, the measured plane element and the reference element are accurately reset, so that system errors are deducted, and meanwhile, the surface reflection interference is separated by using a spectrum estimation algorithm to improve the testing accuracy.
Disclosure of Invention
The invention aims to provide a method and a device for realizing large-aperture plane optical element surface shape detection by sub-aperture splicing phase measurement deflection technology. Aiming at the defects that a large-size display is needed in the traditional phase measurement deflection technology, the resetting precision is difficult to guarantee, the collected stripes are easy to be interfered by the rear surface and the like, the defects of the prior art are effectively overcome by introducing multi-camera collection, reference coordinate plane auxiliary adjustment and spectrum estimation algorithm separation front and rear surface interference. The method well integrates the advantages of the prior art such as phase measurement deflection, sub-aperture splicing technology, spectrum estimation algorithm and the like. The device has the characteristics of simple structure, strong environmental vibration resistance, large measurement dynamic range, high test precision and the like.
The technical scheme adopted by the invention for solving the technical problems is as follows: when the optical element is measured by using the phase measurement deflection technology, basic devices comprise a pinhole camera, a plane optical element to be measured and a display. The sine-coded fringe pattern is displayed on a display, is collected by a pinhole camera after being reflected by a measured surface, and is modulated by the surface shape of a reflector to deform. The surface shape of the measured surface can be obtained according to the deformation of the stripes.
The traditional deflection technique uses a phase shift algorithm to obtain the coordinates (x) of pixel points of the displays,ys) However, when the back surface also has reflection, the fringes of the front and back surfaces will be superimposed to obtain superimposed fringes, and the conventional phase shift calculation method will bring about a relatively large measurement error. One method is to perform blackening or roughening treatment on an optical element to be measured so as to avoid interference of back surface reflection on stripe phase extraction, but the interference causes complicated measurement process and even damages of an optical surface, so the method uses a spectrum estimation algorithm to replace the traditional phase shift algorithm calculation (x) in the inventions,ys). After the display is used for projecting the sine stripes, the signal reflected by the rear surface of the optical element to be measured is regarded as an interference term, and the light intensity signal detected by the CCD can be regarded as the sum of a useful signal and an interference signal. Then, the normalized position information of the projection point of the display required by the PMD to calculate the slope can be regarded as the frequencies of the two periodic signals, and the problem of the algorithmic separation of the interference signals caused by the back surface reflection is essentially the problem of the separation of the two periodic signals.
The specific implementation process is as follows: shooting a series of stripes with equal interval change in period; extracting a group of light intensity values of a single pixel point as a signal (comprising two periodic components) to be analyzed; and calculating Power Spectral Density (PSD), analyzing the frequency spectrum components in the PSD, and finally multiplying the PSD by the width (height) of a screen to obtain the coordinates of the projection point of the display. And then optimizing the coordinates of the projection points of the display calculated by the spectrum estimation method by adopting a direct search method in a nonlinear unconstrained optimization algorithm to finally obtain the coordinates of the pixels of the display.
The problem of back surface reflection interference can be solved by using the method, however, the phase measurement deflection technique is very sensitive to system calibration errors. The invention introduces a method for adjusting the element to be measured with high precision to realize accurate reset in order to ensure that the reference element and the element to be measured achieve good reset precision. It is based on (x) obtained by using calibrationm,ym) Coordinates, and mathematically establishing an ideal coordinate plane (x) on the display planes_ideal,ys_ideal). The coordinates obtained on the display surface by using the spectrum estimation algorithm are compared with the coordinates in an ideal coordinate plane, and the position and the posture of the optical element are repeatedly adjusted for many times, so that the difference between the coordinates is as small as possible, and the ideal resetting precision is achieved.
Using a multi-camera acquisition system to complete sub-aperture data measurement, and then using a splicing algorithm to complete the number of the slopes on the sub-apertures
And according to the splicing, the detection of the surface shape of the large-caliber plane optical element is realized.
Compared with the prior art, the invention has the remarkable advantages that:
(1) compared with the common interferometer, the interferometer is a non-interference measurement mode; the method can effectively inhibit environmental disturbance, has the advantages of large dynamic range of measurement, good anti-vibration capability, simple structure and low cost, and is expected to become a method for realizing online detection.
(2) Compared with the Hartmann subaperture splicing method, the Hartmann resolution is influenced by the size and the number of the micro-lens arrays, and the rate of the invention is only dependent on the resolution of the camera. And more data points are overlapped on adjacent sub-apertures, so that errors caused by splicing due to less data points in an overlapping region can be reduced.
(3) Compared with the traditional phase measurement deflection technology, the invention has three advantages: the rear surface of the planar optical element is not required to be coated with a film or blacked, and the signal separation of the front surface and the rear surface is realized by using a multi-frequency fringe projection method, so that the measurement process is simplified; the reference mirror and the measured mirror are accurately reset by using a simple adjusting method, so that expensive adjusting equipment is avoided; the multi-camera acquisition is used for building the sub-aperture splicing system, and data splicing is realized without using equipment such as a translation table, so that the measurement precision is improved.
Drawings
Fig. 1 is a schematic view of a measuring principle of a planar optical element based on phase measurement deflection.
Fig. 2 is a schematic diagram of a multi-camera phase measurement deflection surgery acquisition system.
FIG. 3 is a schematic diagram of the sub-aperture distribution of the measured surface.
FIG. 4 is a diagram of a designed subaperture splicing device of a large-aperture optical element.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings. It should be noted that the following examples are only for illustrative purposes and should not be construed as limiting the scope of the present invention, and that the skilled person in the art may make modifications and adaptations of the present invention without departing from the scope of the present invention.
The invention comprises an image acquisition system consisting of a plurality of cameras, wherein the principle of phase measurement deflection of one camera is shown in figure 1, and the basic devices of the system comprise a pinhole camera 1, a planar optical element 2 and a display 3. A stripe pattern of sine coding is displayed on a commercial display 3, the stripe pattern is collected by a pinhole camera 1 after being reflected by a measured surface 2, and the sine stripe is modulated by the surface shape of a reflector to deform. The surface to be measured can be obtained according to the deformation of the stripesAnd (5) surface shape. Formula (1) gives the calculation method of the slope value of the point to be measured in the graph. (x)m,ym) Is the coordinate on the measured surface corresponding to the CCD pixel. (x)s,ys) Is the coordinate of the pixel on the display that is lit, (x)c,yc) Is the position coordinate of the pinhole of the CCD camera. dm2sAnd dm2cThe distance from the position of the measured surface to the corresponding pixel point of the display and the aperture of the camera; z is a radical ofm2sAnd zm2cIs the z-direction distance from the vertex of the measured surface to the light source and the camera aperture.
CCD pinhole position (x)c,yc) Can be directly measured to obtain the coordinate (x) of the point M on the CCD pixel corresponding to the measured surfacem,ym) Can be calibrated by a machine vision method. If the coordinates (x) of the display pixel points can be obtaineds,ys) Then, the slope distribution of the measured surface 2 can be calculated by using the formula (1). The measured surface shape can be obtained by using a southwell algorithm or a Zernike polynomial fitting algorithm.
The traditional deflection technique uses a phase shift algorithm to obtain the coordinates (x) of pixel points of the displays,ys) However, when the back surface also has reflection, the fringes of the front and back surfaces will be superimposed to obtain superimposed fringes 4, and the conventional phase shift calculation method will bring about a relatively large measurement error. One method is to blacken or roughen the optical element 2 to be measured to avoid interference of the back surface reflection with the fringe phase extraction, but this is cumbersome. The present invention uses a spectrum estimation algorithm instead of the conventional phase shift algorithm to calculate (x)s,ys)。
(1) Spectral estimation method calculation (x)s,ys)
After projecting the sinusoidal fringe with the display, if the signal reflected by the back surface of the optical element to be measured is considered as an interference term, the light intensity signal detected by the CCD can be expressed as:
Iobs(k)＝Isignal(k)+Ijammer(k) (2) wherein IobsRepresenting the total light intensity, I, detected by the CCD pixelssignalRepresenting a useful signal, IjammerRepresenting The jammer signal (The jammer) and k The number of phase shift steps.
If the subscript "1" represents the useful signal and the subscript "2" represents the interference signal, in combination with the stripe encoding, taking vertical stripes as an example, the formula (2) can be further expressed as
WhereinBackground light intensity, M, of the useful signal and the interfering signal, respectively1，M2Is a corresponding amplitude modulation of the signal to be detected,respectively, the X-direction coordinates of the projection points of the display corresponding to the front and rear surface reflections, p is the fringe period length on the display,is an additional amount of phase shift related to the number of phase shift steps k.
Let wSIs the screen width, then the normalized X coordinate isAt this time, the process of the present invention,which is representative of the left edge of the display,representing the display right sideA rim.
Equation (3) can be written as
wsThe/p is the total number of stripes on the display, denoted by τ, and is considered as the normalized stripe spatial frequency. The constant terms are combined, thus
Wherein,background intensity of the superimposed fringes. By adopting the N-step phase-shifting method,further ignoring the phase shift term, the superimposed signal can be simply represented by the following equation
If τ (fringe spatial frequency) is taken as the independent variable, then the PMD calculates the normalized position information of the display proxels required for the slopeAndit can be regarded as the frequency of two periodic signals, the light intensity signal I detected by any pixel on the CCD is essentially two superimposed periodic signals, and the problem of algorithm separation of interference signals caused by back surface reflection is essentially the problem of separation of two periodic signals.
The specific implementation process is as follows: shooting a series of stripes with equal interval change in period; extracting a group of light intensity values of a single pixel point as a signal (comprising two periodic components) to be analyzed; and calculating Power Spectral Density (PSD), analyzing the frequency spectrum components in the PSD, and finally multiplying the PSD by the width (height) of a screen to obtain the coordinates of the projection point of the display.
The spectral estimation cannot achieve the desired separation accuracy. More importantly, the phase solving problem related to the formula (4) is actually a nonlinear inverse problem, and when a plurality of frequency components exist, the periodogram method is a biased estimation value of the signal power spectrum. Then, the result of the average periodogram method is used as an iteration starting point, a direct search method in a nonlinear unconstrained optimization algorithm is adopted to optimize the coordinates of the projection points of the display calculated by the spectrum estimation method, and finally the coordinates (x) of the pixels of the display are obtaineds,ys)。
The problem of back surface reflection interference can be solved by using the method, however, the phase measurement deflection technique is very sensitive to system calibration errors. The invention introduces a method for adjusting the reference coordinate plane with high precision to realize accurate reset in order to ensure that the reference element and the element to be measured achieve good reset precision.
(2) Accurate reset of reference surface light tracking adjustment method
In a measuring system where z is zmOn the plane of (A), firstly, the (x) of each point in the plane is obtained by utilizing the calibration technologym,ym) And (4) coordinates. Then the light comes from the pinhole (x)c,yc,zc) Emitted via z ═ zmAt a certain point (x) on the surfacem,ym,zm) The reflection reaches the display surface, so that the coordinate corresponding to the reflection point can be obtained on the display surface, and z is equal to zmAll reflection points on the plane of the display surface result in a coordinate plane, defined as the reference coordinate plane (x)s_ideal,ys_ideal). Then the reference element is placed onAdjusting on the adjusting device, shooting a fringe pattern, and forming (x) by using a reference element obtained by a spectrum estimation algorithms,ys) Subtracting the corresponding reference coordinate plane coordinates (x) respectivelys_ideal,ys_ideal) Order:
by adjusting the tilt and pitch of the plate to bring the RMS of dx and dy, respectively, close to zero and the PV to a minimum, a fine adjustment is achieved, the (x) obtained on this premises,ys) I.e. the coordinates that will ultimately participate in the calculation of the slope.
Then, the tested element is placed on the test platform and adjusted in the same way to realize the precise adjustment of the tested element, and the corresponding (x) is obtaineds,ys) I.e. the coordinates of the component which finally participates in the calculation of the slope and restores the surface shape.
Finally, subtracting the reference element profile data from the measured element profile, i.e. D ═ Dtest-DrefThe surface shape data in the sub-aperture can be obtained.
Through the periodogram method, the display coordinate calculation and the accurate adjustment processing method of the element to be detected, the high-precision surface shape detection can be realized on the optical element with small aperture. However, this method is not suitable for measuring optical elements with large aperture. The methods that can be used are: <1> a large-sized display is selected as a projection light source. <2> the PMD test apparatus was translated for splice measurements. And <3> translating the optical element to be measured to realize full aperture measurement. And <4> performing sub-aperture stitching measurement by adopting a multi-camera shooting method.
The method <1> selects a large-size display, which may have the flatness problem, and the gravity of the display itself may cause the display surface shape error, which causes unnecessary trouble to the system calibration. The method <2> carries out sub-aperture splicing measurement by moving the measuring equipment, but the requirement on the translation device is high, and the straightness and the translation precision of the guide rail directly influence the testing precision. The method <3> needs to adjust the position of the device to be tested by using the guide rail, and obviously, the device to be tested can not move even if online detection needs to be realized. Therefore, the method <4> is adopted, the multi-camera acquisition is adopted, and then the sub-aperture splicing method is carried out to realize the detection of the large-aperture planar optical element.
(3) And (3) multi-camera acquisition, and detection of the large-caliber planar optical element is realized by adopting a sub-aperture splicing algorithm.
The multi-camera acquisition system can be two or more, the number is not limited, and here, an acquisition system consisting of six pinhole cameras (numbered 5,6,7,8,9 and 10), a display 11 and a display adjusting device is provided, and schematic diagrams are shown in fig. 2(a), (b). The horizontal adjustment mechanism 12 and the rotation adjustment mechanism 13 of the display in fig. 2(b) enable the pixels in the display to be on the same plane, and the camera pinhole 14 in fig. 2(c) enables the measured surface of the element to be correctly selected through the camera orientation adjustment mechanisms 15, 16 and 17. After the above adjustment is completed, the measured planar optical element is assumed to have a length L and a width W. The situation that the sub-apertures of the covered tested elements are measured by 5,6,7,8,9 and 10 cameras is shown in FIG. 3, A5-A10 in FIG. 3 are ranges on the tested surface measured by 5-10 pinhole cameras respectively, and the length and width of the sub-apertures measured by each camera are L1 and W1 respectively. The grid area is the overlapping area between adjacent sub-apertures, and the diagonal stripe area is the non-overlapping data area of each sub-aperture. In the measurement process, the measured element and the multi-camera acquisition system are placed on an optical bench, and fig. 4 is a schematic diagram of the designed large-caliber planar optical element surface-shaped sub-aperture splicing detection technology and device. For accurate measurement, the present invention places the device under test on the adjusting device 18, as shown in fig. 4, where the horizontal adjusting mechanism 19, the device supporting plate 21, the device supporting plate fixing frame 24 and the device supporting plate orientation adjusting knobs 22 and 23 in fig. 4 can align the device under test 20 with the display 11 in the testing state.
Assuming two adjacent sub-apertures a5 and a6, the measured profile distributions are Φ 1 and Φ 2, respectively. Assuming that a5 is a reference plane, Φ 1 and Φ 2 satisfy the following relationship in the overlapping region:
Φ2＝Φ1+P+Txx+Tyy, (8)
wherein P represents the amount of translation, Tx and Ty represent the tilt coefficients in the x and y directions, respectively,
the partial derivatives in the x and y directions are obtained by the above formula
WhereinThe derivatives of a5 in the x and y directions, respectively.The derivatives of a6 in the x and y directions, respectively. Assume that the overlap region has n sample points in total. The corresponding matrix form of the formula (9) is
The tilt coefficients Tx and Ty in the x and y directions can be obtained by the least square data processing method, and the correction results of G2x and G2y can be obtained by equation (9). Then, the correction results of G2x and G2y are spliced with those of G1x and G1y, so that the splicing slope data of two adjacent regions can be obtained. By analogy, slope distribution on all sub-apertures can be obtained through similar splicing treatment, and further the surface shape of the large-aperture plane optical element to be detected is obtained.
Claims (4)
1. The sub-aperture splicing detection method for the surface shape of the large-aperture plane optical element is characterized by comprising the following steps of: the system comprises an image acquisition system consisting of a plurality of cameras, a display serving as a system device of a stripe projection device, and deformed stripes reflected and superposed by front and rear surfaces, wherein if a signal reflected by the rear surface of an optical element to be detected is regarded as an interference item, a light intensity signal detected by a CCD can be represented as follows:
Iobs(k)＝Isignal(k)+Ijammer(k) (1)
wherein IobsTo representTotal light intensity, I, detected by CCD pixelsignalRepresenting a useful signal, IjammerRepresenting the interference signal, k representing the number of phase shift steps; if the subscript "1" represents the useful signal and the subscript "2" represents the interfering signal, in combination with the stripe encoding, the formula (1) can be further expressed as follows, taking vertical stripes as an example:
whereinBackground light intensity, M, of the useful signal and the interfering signal, respectively1，M2Is a corresponding amplitude modulation of the signal to be detected,respectively, the X-direction coordinates of the projection points of the display corresponding to the front and rear surface reflections, p is the fringe period length on the display,is an additional amount of phase shift related to the number of phase shift steps k; let wSIs the screen width, then the normalized X coordinate isAt this time, the process of the present invention,which is representative of the left edge of the display,representing the right edge of the display; equation (2) can be written as:
wsp is an indicationThe total number of stripes on the device is represented by tau and is regarded as normalized stripe space frequency; the constant terms are combined, thus:
wherein,background light intensity of the superimposed stripes; by adopting the N-step phase-shifting method,further ignoring the phase shift term, the superimposed signal can be simply represented by the following equation:
if τ (fringe spatial frequency) is taken as the independent variable, then the PMD calculates the normalized position information of the display proxels required for the slopeAndthe method can be regarded as the frequency of two periodic signals, a light intensity signal I detected by any pixel on a CCD is essentially two superposed periodic signals, and the algorithm separation problem of interference signals caused by rear surface reflection is essentially the separation problem of the two periodic signals; the specific implementation process is as follows: shooting a series of stripes with equal interval change in period; extracting a group of light intensity values of a single pixel point as a signal (comprising two periodic components) to be analyzed; calculating Power Spectral Density (PSD), analyzing the frequency spectrum components in the PSD, and finally multiplying the PSD by the width (height) of a screen to obtain the coordinates of the projection point of the display; simultaneously, a reference coordinate plane is introduced when the optical element of the measured plane and the reference plane element are adjusted, so that the light of the measured plane is realizedThe optical element and the reference plane optical element are accurately reset through the adjusting device, the measured plane optical element data obtain the surface shape on a single aperture after deducting the surface shape data of the reference plane optical element, the slope data on the corresponding sub-aperture area shot by each multi-camera is obtained through the sub-aperture slope splicing algorithm, and then the full aperture surface shape distribution is obtained through reconstruction.
2. The method for detecting the surface shape of the large-caliber planar optical element according to claim 1, wherein a reference coordinate plane (x) is introduced into the display planes_ideal,ys_ideal) The precise resetting of the reference element and the measured optical element is realized through the adjusting device; the specific form is as follows:
in a measuring system where z is zmOn the plane of (A), firstly, the (x) of each point in the plane is obtained by utilizing the calibration technologym,ym) Coordinates; then the light comes from the pinhole (x)c,yc,zc) Emitted via z ═ zmAt a certain point (x) on the surfacem,ym,zm) The reflection reaches the display surface, so that the coordinate corresponding to the reflection point can be obtained on the display surface, and z is equal to zmAll reflection points on the plane of the display surface result in a coordinate plane, defined as the reference coordinate plane (x)s_ideal,ys_ideal) (ii) a Then the reference element is put on a test platform for adjustment, a fringe pattern is shot, and then the reference element obtained by a spectrum estimation algorithm is formed into (x)s,ys) Subtracting the corresponding reference coordinate plane coordinates (x) respectivelys_ideal,ys_ideal) Order:
then the pitch and the tilt of the reference plane element are adjusted by the adjusting device to respectively make dx and dy approach xs_idealAnd ys_idealThen calculating the RMS and PV, and finishing the fine adjustment of the reference element when the value is minimum; this is achieved byObtained when (x)s,ys) Namely, the coordinates which finally participate in the calculation of the slope and the surface shape is recovered; then, the measured element is placed on an adjusting device and adjusted in the same way as above to realize the precise adjustment of the measured element, and the corresponding (x) is obtaineds,ys) Namely, the element finally participates in calculating the coordinates of the slope and recovers the surface shape; finally, subtracting the reference element surface shape data from the measured element surface shape to obtain the surface shape data in the sub-aperture, and calculating according to the following formula:
D＝Dtest-Dref (7)
3. the large-aperture plane optical element surface shape sub-aperture splicing detection method according to claim 1, characterized in that a fringe pattern formed by reflection of each sub-aperture on the acquisition element is shot by a multi-camera to obtain surface shape data obtained on each sub-aperture, and then the surface shape detection of the large-aperture plane optical element is realized by using a sub-aperture splicing algorithm.
4. The method as claimed in claim 1, wherein a single camera of the apparatus is used to perform surface shape detection of the large aperture device after subtracting the surface shape data of the reference plane optical device from the data of the measured plane optical device.
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| CN108413894A (en) * | 2018-03-12 | 2018-08-17 | 四川大学 | A kind of phase measurement deviation art method of shearing dislocation absolute measurement |
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| CN114593693B (en) * | 2022-02-16 | 2022-11-01 | 苏州英示测量科技有限公司 | Optical deflection detection method, electronic device and optical deflection detection system |
| CN115164778B (en) * | 2022-07-07 | 2024-07-23 | 四川大学 | Device and method for measuring heavy caliber optical element gravity deformation based on deflection operation |
| CN117516415B (en) * | 2024-01-05 | 2024-03-08 | 南京施密特光学仪器有限公司 | Zernike fitting knife-edge shadow map wavefront reconstruction surface shape detection method, device and system |
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| CN100419399C (en) * | 2007-01-30 | 2008-09-17 | 北京理工大学 | Random pattern measuring method for statistic modulation transfer function |
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