Pointcloud noncontact metrology of freeform optical surfaces. Dynamic metrology holds the key to overcoming several challenging limitations of conventional optical metrology, especially with regards to precision freeform optical elements. Demonstrates a method of using a laser tracker, a simple special fixture and a point source microscope psm to create a virtual spherical mounted retroreflector smr for situations where a smr cannot be attached to the surface to be measured. Singleshot deflectometry for dynamic 3d surface profile. Tiptilt tests by using eddy current measuring sensors. Anglescentroids fitting calibration and the centroid. Ci provides test benches or stations for electro optical eo systems composed of multiple sensors or channels.
The scots can be better understood as doing a traditional hartmann test with the light going through the system in reverse. Therefore, the necessary quantity of captured fringes is very large, especially for the fringe reflection technique frt, since a pair of phases should be unwrapped to get the slopes of two. A software configurable optical test system scots based on the geometry of the fringe reflection or phase measuring deflectometry method was developed for rapidly, robustly, and accurately measuring large, highly aspherical shapes such as solar collectors and primary mirrors for astronomical telescopes. A software configurable optical test system scots based on.
Burge1,2 1college of optical sciences, the university of arizona, tucson, arizona 85721, usa. Optical perspectives group, llc is an optical engineering consulting firm specializing in the hardware aspects of optics, particularly the fabrication, testing, assembly and. Research on the relationship of the probe system for the swing arm profilometer based on the point source microscope, m. Then, as a consequence, the spots are not focused on the measuring plane, as in the original hartmann test. Along with experimental data showing the capabilities of the instantaneous.
Scots uses a camera with an external stop to realize a hartmann test in reverse. A linear translator 50 controlled by processor 48 provides for relatively moving the test element 42 along a common optical axis 52 of the interferometer 10 and the test element 42. Measuring aspheric surfaces with reflection deflectometry. In its simplest configuration, all that is needed to perform the test is a laptop computer with a builtin camera. Method of alignment using a laser tracker system abstract. The ccd camera works as the point source and the screen has the function of the detector in a hartmann.
Software configurable optical test system advanced deflectometry system measuring surface slope with both high precision and large dynamic range. Fast temporal phase unwrapping method for the fringe. Phasemeasuring deflectometry pmd has been developed at erlangen to measure spatially resolved slope data of specular surfaces 1, 2 and 3. With the external camera stop as the reference, a coordinate measuring machine can be used to calibrate the. The work focuses on the structural design and performances of a unique optical test system ots used for measuring metrescale optical surfaces. A camera observes the image of a sinusoidal grating via reflection at the surface under test. We have developed a softwareconfigurable optical test system scots that. These benches are built to provide a comprehensive turnkey solution for all the sensors testing needs of the eo system in question. We propose a new concept of singleshot deflectometry for realtime measurement of threedimensional surface profile using a single composite pattern. And it seems there is a shack hartmann analyser, where can i download it. If the ruling is substituted by a dark screen with a rectangular array of holes, as in fig. Mar 01, 2014 read aspheric and freeform surfaces metrology with software configurable optical test system. A computerized reverse hartmann test article pdf available in applied optics 4923.
Point source microscope optical perspectives group. A software configurable optical test system scots based on the geometry of the fringe reflection or phase measuring deflectometry method was developed for rapidly, robustly, and accurately. Scots software configurable optical test system is a useful tool that can provide lens manufacturers with the ability to evaluate the net performance of a lens system without the use of complex metrology systems and setups. Software configurable optical test system scots1, a computerized reverse hartmann test, can rapidly quantitatively measure highly aspherical shapes such as solar collectors, giant magellan telescope gmt primary segment with accuracy to micron rms or better without complex calibration. A software configurable optical test system scots based on deflectometry was developed at the university of arizona for rapidly, robustly, and accurately measuring precision aspheric and freeform surfaces. Modal data processing for high resolution deflectometry. Accuracies in the range of 100 200 nrad rms have been achieved ref.
Computeraided highaccuracy testing of reflective surface. Hartmann test and b our softwareconfigurable optical test system scots. Aspheric and freeform surfaces metrology with software configurable optical test system. The laptop illuminates the test surface with a light pattern on the lcd screen and uses the reflected im. Us5416586a method of testing aspherical optical surfaces. In addition to using phase shifting methods for data collection and reduction, we explore. A lowcost, flexible, high dynamic range test for freeform. The deflectometry provides a feasible way for surface testing with a high dynamic range, and the calibration is a key issue in the testing. A new test for optical surfaces university of arizona. In traditional temporal phase unwrapping tpu algorithms, wrapped phases with different spatial frequencies are obtained from several groups of phase shift fringes to calculate the unwrapped phase.
This paper mainly elaborates application and development of wavefront sensing technology in different fields. Dec 01, 2015 software configurable optical test system scots is one of such pmd tests and has been applied for various astronomical optics including 8. Faststeering secondary mirror fsm will be installed to the giant magellan telescope gmt as a first generation secondary mirror. Page 1 of 2 interferometer software and hartmann test software posted in atm, optics and diy forum. The small imaging lens and the virtual object are at conjugate positions, where the lens is assumed to be working. A lowcost, flexible, high dynamic range test for free.
However, commonly used methods do not always ensure rapid and accurate measurement of different types of convex aspheric surfaces because it is difficult to collect. It is widely used in adaptive optics, laser beam quality diagnosis, laser atmospheric communication, optical element and optics system detection, quantitative phase microscope, human eye aberration measurement and other fields. Aspheric and freeform surfaces metrology with software configurable. A computerized reverse hartmann test peng su, manal a.
Software configurable optical test system scots is a simp le, lowcost yet highly flexible optical test that can be configured with software for almost any specular freeform surface. Integrated ray tracing simulation of the scots surface. Dominguez, alejandro maldonado, guillaume butel, yuhao wang, robert e. Both modal analysis of the entire ots and transmissibility function related to its use as an optical system are carried out and analysed. Journal preproof 3d shape measurement of convex aspheric surface using reverse hartmann test shanshan wang, yinlong hou, dawei li, qiudong zhu pii. In detail, if the tested mirror is described by equation z wx, y in a global coordinate system, an arbitrary point m on the test sample will have the coordinate mx m, y m, z m. The scots uses the same basic test geometry as the fringe reflection technique or phase measuring deflectometry pmd 2, 3. Application and development of wavefront sensor technology. In recent years, phase measuring deflectometry pmd, and software configurable optical test system scots,, have been developed to test the optical concave aspheric surfaces. The fsm implements a tiptilt mechanism which compensates image degradations caused by wind turbulence and structure jitter. Figure 1b shows schematically how the surface slope is measured and calculated. Pdf aspheric and freeform surfaces metrology with software.
In this paper, we develop an anglescentroids fitting acf system and the centroid algorithm to calibrate the reverse hartmann test rht with sufficient precision. Based on the finely engineered system hardware, a comprehensive system model was developed capable of characterizing the vertical displacement sensitivity and lateral scanning noise. Electro optical test systems optical test equipment ci. During a test, an intensity pattern is displayed on the lcd. Interferometer software and hartmann test software atm. The ronchi test 14, as the hartmann test, measures the transverse aberrations, but only in one direction, perpendicular to the lines in the ronchi ruling. Software configurable optical test system semantic scholar. The instantaneous method is based on multiplexing phase shifted fringe patterns with color, and decomposing them in x and y using fourier techniques.
A computeraided testing method based on reverse hartmann test, a fringeillumination deflectometry, is proposed for highaccuracy testing of reflective surfaces. In addition to these methods, another technique is the software configurable optical test system scots, which is based on a hartmann test and uses similar geometry principles as the nullscreen. Then, by taking a picture of the test mirror using a camera, we will know the position of the reflected point. Aspheric and freeform surfaces metrology with software. Software configurable optical test syst em scots, a computerized. Methodology of quantifying curvature of fresnel lenses and. The investigation was carried out through a modal analysis. Pdf measuring aspheric surfaces with reflection deflectometry. The flat display is set up with its screen near the. Quantitative deflectometry challenges interferometry. Su p, parks r e, wang l, angel r p and burge j h 2010 software configurable optical test system.
Scots uses the same basic test geometry as phasemeasuring or fringereflection deflectometry. A computerized reverse hartmann test, abstract a software configurable optical test system scots based on the geometry of the fringe reflection or phase measuring deflectometry method was developed for rapidly, robustly, and accurately measuring large, highly aspherical shapes such as solar collectors and primary mirrors for astronomical telescopes. Hi, i know atmosfringe, but it is expensive, is there other choice for interferometer software. Abstract software configurable optical test system scots1, a computerized reverse hartmann test, can rapidly, robustly and quantitatively measure complex 3dimensional specular surfaces, for instance large segmented solar collectors, faceted automotive headlight reflector or other freeform surfaces. The software configurable optical test system scots is a simple, inexpensive, yet highly flexible optical test that can be configured with software for almost any specular surface or lens system. Dynamic metrology and data processing for precision freeform. Nonnull full field xray mirror metrology using scots.
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