Apparatus For Wavefront Error Sensor Measurement:
Apparatus for Wavefront Error Sensor Measurement:CDRDecember 12, 2017Authors: Robert Belter, Ali Colic, Jake Crouse, LucasDroste, Diego Gomes, Ankit Hriday, Owen Lyke,Brandon Noirot, Owen Shepherd, and Brandon StetlerCustomer: Eliot YoungSouthwest Research Institute&NASA Glenn Research Center
1.0 PROJECT PURPOSE ANDOBJECTIVES2
1.1 - IntroductionOptical systems are susceptible to small errorsimparted from the environment and the tolerancesin the systemActive optics (AO) uses wavefrontmeasurements to correct optical systems3
1.1 - Wavefront Sensors A wavefront is a continuous constant-phasesurface of light from one source At the focal point of the system, deviation fromspherical wavefront is wavefront error Shack-Hartmann Array (SHA) vs.Roddier Curvature Wavefront Sensor (RCWS)Shack-Hartmann Method(Below)Roddier Method (Left)4
1.1 - MotivationPotential benefits of RCWS: Simplicity in design: Optics systems generally have a system for changing the focal length No need to access the pupil Can use the main image detector The RCWS method has the potential to perform equally or even better thanthe currently used methods on aerial platforms as long as it meetsperformance expectations. Future missions could choose SHA or RCWS systems based onperformance data generated by a comparison5
1.2 - Objectives Quantitatively compare the SHA andRCWS wavefront sensors as a function ofsource intensity Measure the rate of response of detectedZernike polynomials to introduced error forboth sensors Design and build a test platform that facilitatesdata collection with required precision andaccuracy Develop a prototype Roddier sensor to beused in the comparison Use forward-predictive models to drive thedesign and validate results Present preliminary results6
1.3 - CONOPS7
1.3 - CONOPS Part 18
1.3 - CONOPS Part 29
1.3 - CONOPS Part 310
2.0 DESIGN SOLUTION11
2.0 - Design Solutions The following section presents at a high level the design solution chosen to proceedElementPurposeImage SourceProvide known conditioned state at the input to thesystemOptical SystemIntroduce wavefront error and focus image to sensorsShack-Hartmann ArrayTest Article #1Roddier Curvature WavefrontSensorTest Article #2TestbedAlign, isolate, and protect optical componentsEnvironmental Sensor SystemTrack environmental changesRCWS AlgorithmCompute RCWS Zernike amplitudes from RCWS dataTest Control SoftwareAutomate test procedure and perform data handling12
2.0 - FBD13
2.0 - FBD Part 114
2.0 - FBD Part 215
2.0 - System Overview16
2.1 - Image SourcePurpose: The image source provides aspherical source wavefront inorder to appear as a distant starto the image detectors. The source also tests thesensors over a range ofintensities to determine if andwhen their performancesdiverge.17
2.1 - Image SourceRequirements: The emitted wavefront must bespherical The source must emit a uniformintensity distribution The intensity of the source must bevariable to 1/128 of the maximumintensity18
2.1 - Image SourceLensOptical fiber entranceEmitter19
2.2 - Optical SystemPurpose: Forms an image of the apparentdistant image sourceIntroduces known wavefront error byrotation of mirror M2Requirements: RCWS24 in Must introduce wavefront error inincrements smaller than the desireddetection resolutionIntroduce useful combinations ofZernike polynomial coefficients to fullytest the RCWS algorithmMirror M2Beam SplitterSHAImage SourceYXMirror M1Z48 in20
2.2 - Optical SystemY - TranslationZ– TranslationX - TranslationAlignment Degrees of Freedom Minimizing the number of degrees of freedomto fully align the system reduces resourcesspent on costly precision stages.Mirror 1 is fixed to the testbed, mirror 2 usestwo rotational movements to align.The pellicle is large enough to remain fixed.The wavefront sensors must traverse to thefocal point of mirror 2 and tilt in two directionsto remove initial errorsThe image source must translate to the focalpoint of mirror 1.Y - RotationX - RotationYXZ21
2.3 - Wavefront SensorsPurpose: The wavefront sensors are the testarticles for the experiment.Shack-Hartmann Array:Requirements: A Shack-Hartmann Array sensor fromThorlabs will be provided A Roddier Curvature WavefrontSensor must be developed usingCOTS componentsRoddier Method:22
2.3 - Wavefront SensorsShack-Hartmann Array Provided by the customerInterfaces to a PC overUSBSupplied with software todetermine standardZernike coefficientsMay be operated without acollimating lens in adivergent or convergentbeamOperation of WFS150-7AR in a divergent/convergent beamThorlabsWFS150-7AR [7]Zernike coefficient output from Thorlabs provided software23
2.3 - Wavefront SensorsRoddier Curvature Wavefront Sensor Developed from COTS parts because no commercial RCWSexistComprised of CMOS camera and precise linear traverse fordefocusCMOS and travers interface to PC via USBTwo CMOS detectors provided by the customer ASI120MM QHY174MThorlabs PT1-Z8traverse [4], 50 nm stepsize, 1 inch travel5.86µm pixels:Low shot noise:3.75µm pixels:Small detector:QHY174M CMOSDetector [3]ASI120MMCMOS Detector [2]24
2.4 - Environmental SensorsPurpose: Record thermal and vibrational data during test sequence to verify that error sources are below threshold.Requirements: Accelerometers must be able to correctly capture frequencies up to 300 Hz, and sample at1kHz (Requirements: 6.1, 6.3) Temperature sensors must be able to measure at a minimum resolution of 0.15 K, aminimum accuracy of 0.5 K, and sample at a rate of 1Hz (Requirement: 6.2) Sensor data shall be communicated to the testbed control computer for the duration of thetest sequence (Requirement: 6.4)Overview 12 total sensors – 6 temperature and 6 accelerometers – will be placed throughout thetestbed and the optical components to collect local environmental data. The sensors will be interfaced with a microcontroller to relay data to a computer25
2.4 - Environmental Sensors Component Choices: Microcontroller: Teensy 3.6 PC Interface : Serial USBconnection Accelerometer: ADXL 344 Temperature Sensor:ADT7320 Overall SchematicADXL344 Requirements and PerformanceSampling RateSPI Data RateResolutionFiltering?Requirement:1 kHz0.55 MHzNAYesADXL-344Performance3.2 kHz(Maximum)5 MHz ( 5 𝑀𝑏𝑝𝑠) 3.9𝑚𝑔YesADT7320 Requirements and PerformanceSampling RateSPI Data RateResolution16 bit (13 bit) [ C]Accuracy [ C]Filtering?Requirement:1 Hz0.55 MHz 0.15 0.5NoADT73204 Hz (Maximum)5MHz ( 5𝑀𝑏𝑝𝑠) 0.0078( 0.0625) 0.31No26
Sensor Locations2.4 - Environmental Sensors1.5 in2 inADT7320PCB0.55 inADXL344PCB0.9 in27
2.5 - TestbedPurpose The testbed allows for alignment and structuralsupport of the optical elements.The testbed also provides thermal and vibrationaleffect damping.The testbed reduces external light contamination.Requirements The testbed must allow for alignment of individualelements to within 1% change in Strehl ratio.The test area must be contained within a 2' x 4'sectionOverview Degrees of freedom for alignment other than theRCWS traverse and M2 tip/tilt platform will be setusing manual PT1B traverses and KM100WFStip/tilt stages from Thorlabs.28
2.5 - TestbedTest Location: SwRI: 1050 Walnut St. Boulder CO. 1.5 miles from CU engineering center withpublic transit availableSharing optical table space (allotted 2'x4'section)Allotted 6 week minimum residenceOptical Table: Newport RS200010' x 5' x 2'1 inch spaced ¼-20 tapped holesTuned damping and CTEVibration isolating legsOptics table from Newport [1]29
2.6 - Test SoftwarePurpose: Automate test execution.Enable larger data sets to be collected.Reduce human error.Improve ease of recording andtransporting data.Requirements: Interface with motorized stagesInterface with wavefront sensorsInterface with environmental sensorsystemExecute a specified test plan given mirrortilts, RCWS defocus distances, andreceive intensitiesCompute Zernike amplitudes givenRCWS intensity and defocus dataCompare response on RCWS to SHA30
3.0 CRITICAL PROJECT ELEMENTS/4.0 DESIGN REQUIREMENTS AND THEIRSATISFACTION31
3/4 - Critical Project Elements and Design Requirements andSatisfactionTest Platform Considerations: Obtaining quality scientific data about the performance of the two sensors is key.Most critical elements are concerned with reducing or reporting error in the test.Other key CPE's stem from customer-specified requirements.In consideration the following section will present key CPE's alongside the models that validate the designchoices made in the platformDesign ElementKey Critical Project ElementsImage SourceImage Size, image Intensity, image variation, image stabilityOptical SystemIntroduction of Zernikes, resolution of introduced errorRoddier Curvature Wavefront SensorDefocus plan, image spillRCWS AlgorithmBi-directional operation, RCWS reading interpretationEnvironmental Sensor SystemThermal sensitivity, vibrational sensitivity, sensor placement, and data rate32
3.1/4.1 - Image SizeCritical Factor: The source must emit a spherical wavefront,otherwise the optimal alignment will exhibitwavefront error that may wash out intentionalaberrationsModel: The pinhole stops acting as a point sourcewhen the diameter exceeds the size out to thefirst minimum of the diffraction pattern.Pinhole diameter at 550nm center wavelengthcan be at most about 16 µm Worst case value using blue light (smallestwavelength) yields 13 µm Standard 10 µm pinhole suits needs, and isreadily available33
3.2/4.2 - Image Source Maximum Power Output RequiredCritical Factor: The image source must produce enough intensityto meet 10,000 photons per exposed pixel onaverage in order to obtain maximum SNR of 100Model: Developed MATLAB model to determine if sourcedesign can meet minimum light requirement Major assumptions: No Light scattering All light reflected off M1 hits M2 Only interested in first airy minimum, whichtypically contains 83% of intensity Results: 6.140663e-09 watts of light required out ofpinhole34
3.3/4.3 - Maximum Power Output Produced Major assumptions: LED emits isotropically Thin lens assumption Major equations: Thin lens equation: Trigonometry Results: This configuration can output 1.9496e-07watts This is more than enough to satisfy therequirement previously stated35
3.4/4.4 - Image Intensity VariationCritical Factor: The received intensity must vary across a range todetermine at what conditions the performance of the twowavefront sensors diverge.Model: Changing image intensity is most easily achieved by varyingexposure time of the detector Simple relationships where number of photons onto detectoris directly related to exposure time Results: Exposure 16.67ms (1/60 seconds) to 130.2µs (1/7680seconds) Both RCWS and SH array can accommodate this range RCWS Range: 50µs to 1800s SHA Range: 79µs to 65ms Full range of 1 to 1/128 of full intensity is achievable usingshutter speed adjustment in software36
3.5/4.5 - Image Source StabilityCritical Factor: Operation of the RCWS is based on the gradient of intensityover the defocus range. In the time spent translating by theRCWS detector intensity fluctuations from the image sourcemay impart unacceptable error in measured Zernike amplitudes.Model: Stability analysis was done to determine maximum allowablecurrent ripple of LED power supplyLED Intensity needs to go from full power to 1/128 in scales of ½Which gives smallest change in LED output power and thensmallest change in input currentResults: 15.5566 mA is the largest allowable current rippleChosen Meanwell HLG-60H-36A power supply has ripple ofapproximately 7mA37
3.6/4.6 - Optical System Error IntroductionCritical Factor: The customer has specified that theresolution of wavefront error at which thesensors shall be compared is a 1/50change in Strehl ratio. In order to makethis comparison the optical system mustintroduce error at least at this resolution.Model: Zemax used to obtain linearized Strehland Zernike sensitivities about aperfectly aligned system.Small angle approximation used todetermine tip and tilt that produce 1/100change in Strehl ratio.Results– Tip/tilt resolution minimum is 216 arcseconds Tip/tilt platform step size is 15 arcseconds38
3.7/4.7 - Tip/tilt to Zernike Transfer FunctionCritical Factor: Need to feed Zemax model actual mirror aberration in 6 DOF forresult verification.Unique Zernike modes need to be introduced to sufficiently test theRCWS algorithm.Model: Mechanical movement modeled geometrically.Introduced Zernike modes linearized about S 1 system usingZemax.Vector r gives both translational and rotational offsets of the mirror.Vector z gives first 12 Zernike mode coefficients.Sensitivities of Zernike modes to 6 DOF of mirror are given inmatrix M.39
3.7/4.7 - Tip/tilt to Zernike Transfer FunctionResult: A well-defined relationshipbetween the commanded pitchand yaw angles and the outputZernike amplitudes has beenfound.Can be applied to feed predictivemodels in the test phaseGiven enough mirror deflection itis possible to set any two Zernikeamplitudes.However there are limitingfactors such as beam spill andoptical table real estate that willlimit the reachable solutions.40
3.8/4.8 - RCWS Defocus PlanCritical Factor: Minimize error within the RCWS system with an optimal defocus distance.Model:Purpose: Experimentally determining the optimal defocus distance of the RCWS. This is difficult to determine analytically, so an experimental approach will be taken.Limitations: Compares performance to the Shack Hartmann Array. Uses discrete 0.05 inch jumps in RCWS defocus distance.Assumptions: The Shack Hartmann Array is correctly calibrated.Image intensity is constant over all tests.Image sensor exposure time is constant over all tests.Optimal translation distance for each intensity is constant over all tip/tilt angles.Rate of change over each set of tests is linear.41
3.8/4.8 - RCWS Defocus PlanTest # All 100 tests are conducted at the same intensity. These tests will then be repeated for each new intensity,as the optimal defocus could be different for eachintensity level. Each set of five tests will be utilized to determine the rateof change RCWS t -0.1350-0.1350-0.1350-0.1350-0.1350-0.1350-0.13542
3.8/4.8 - RCWS Defocus Plan The expected form of results from Defocustesting. The only variable is the RCWS defocus,which won't affect the performance of theSHA. As such, the SHA performance isconstant.43
3.9/4.9 - Detector Image SpillCritical Factor: The image must stay on the RCWS image sensor during the course of a capture cycle.Model:Purpose: Ray tracing program created to determine if the focused light from M2 is falling onto the RCWSboth fore and aft of the focus.Determine amount of tip and tilt can be achieved on M2 with the selected linear traverse.Determine required translation of RCWS linear traverse.Limitations: Breaks down at large tip/tilt angles.1 degree of freedom, so either tip or tilt, not both.Assumptions: Image on RCWS is always circular.Image occurs only within the optical cone.RCWS traverse is aligned with the optical axis of perfectly-aligned M2.44
3.9/4.9 - Detector Image Spill Result: The leftmost plots represent the image spots on the RCWS with no offset from M2 optical axis. With anadjustment of 0.5mm of the RCWS translational plane, the image can be shifted to be entirely on the RCWS.45
3.9/4.9 - Detector Image SpillRCWS Ray Tracing - Top View Top View showing possible rangeof the RCWS translational stage.Shown with M2 tilt 0.135 degree.46
3.10/4.10 - RCWS Interpretation AlgorithmCritical Factor: The RCWS algorithm must produce Zernike polynomials from image data.Model:Purpose: Calculate Zernike Coefficients from RCWS intensity matrix output.Assumptions: The RCWS defocused to the commanded defocus distance Auxiliary light sources are negligible.Limitations: As the defocus distance becomes too large, the blur decreases the image resolution. As the defocus distance becomes too small, the number of intensity values yielded are notsufficient to calculate higher order Zernike Coefficients.47
3.10/4.10 - RCWS Interpretation Algorithm Previously generated images were converted intoarrays of intensity values. These intensity values were then run through theRCWS interpretation algorithm to see if the sameZernike Coefficients were produced.This RCWS interpretation algorithm depends onthe Poisson Equation:This is difficult to solve, and two main methodsfor doing so: FFT Method Zernike Matrix Method48
3.11/4.11 - Zernike Amplitude to Defocused Image ModelCritical Factor: Independently validate Zernikes produced by RCWS algorithm.Potentially the assumption that the SHA gives "truth" could be refuted if RCWS and forward predictive modelresults match despite disagreement between SHA and RCWS.Provide increased confidence when observing defocused images in experiment.Model:Purpose: Simulate RCWS Images solely from Zernike polynomials.Validate the Zernikes produced by the RCWS system.Verifying the wavefront errors we are introducing will be detectable by image sensors.Assumptions: Zemax produces correct Zernike coefficients.Limitations: PROPER limits how small the RCWS defocus distance can be.Dependent on the resolution of the CMOS being modeled.49
3.11/4.11 - Zernike Amplitude to Defocused Image Model Example output at very small defocus distance. Few pixels illuminated Differences in intensity are largeTilt: 1 degreeDefocus: 100 micrometersTilt: 1 degreeDefocus: 200 micrometers50
3.11/4.11 - Zernike Amplitude to Defocused Image Model Example output at mid defocus distance. More pixels illuminated for more data points. Differences in intensity are less, potentially increasing error in determining Zernike amplitudesTilt: 1 degreeDefocus: 400 micrometersTilt: 1 degreeDefocus: 800 micrometers51
3.11/4.11 - Zernike Amplitude to Defocused Image ModelTilt: 1 degreeDefocus: 1600 micrometersTilt: 1 degreeDefocus: 3200 micrometersTilt: 1 degreeDefocus: 6400 micrometers52
3.12/4.12 - Testbed Thermal ModelCritical Factor:A relevant breadboard areaα coef. of planar thermal expansion Thermal effects may deform the optical system therebyT temperatureintroducing wavefront error that decreases the SNR. Minimumresolution of temperature data to avoid such errors will beTable 1: Change in Strehl ratio due to elongation in Z-axisdetermined.Image Source - M1M2 - SensorsModel:0.4735/mm0.2440/mmdS/dzPurpose: Identify significant sources of error or changes to optical pathResultsdue to thermal effects- A ΔT of 1.414K, the expansion creates a 1% Quantify the changes in testbed alignment due to thermalchange in Strehl ratioexpansionAssumptions:- Each 1K change in temperature causes a ΔZ of 2-D thermal expansion is sufficient8.87µm, and a ΔX of 3.70µmX Y-direction expansion insignificant Solid aluminum of uniform coefficient of thermal expansion of- Minimum accuracy of temp. sensors 1.0K23.6 µm / (m K) @ room temperature Main source of heat is surrounding airZ(Y is out of page) Image source location is remote to table53
3.12/4.12 - Testbed Thermal ModelΔZMirror M2Pellicle andSensorsImageSourceXΔXZ(Y is out of page)Mirror M1Optical breadboard experiencing uniform, planar thermalexpansion Increase in temperature ofbreadboard (chiefly due tosurrounding air) causesuniform expansion of the table. From the Zemax model used tovalidate the optical system:Overall elongation/contractionof all or some parts of theoptical path results in changeto the Strehl ratio This change is negative ifthe path expands, and viceversa54
3.13/4.13 - Testbed Vibrational ModelCritical Factor: Vibrations present on optical components cause displacements that introduce noise in wavefront measurements.Understanding the nature of these vibrations informs the environmental sensor system of necessary sensorresolution and placement, as well as test invalidating conditions.Model:Purpose: Model movement of the mirrors with respect to forcing function applied to the optical tableUsed to determine the maximum allowable forcing that can occur during a test while maintaining acceptable errorsCould predict settling time of the system if damping terms could be estimatedCould be used to predict the measurements made by accelerometersCan predict "initial condition" response without an input forceAssumptions: Only the two mirrors move because they are tall and massiveNo slop in mounting hardware consideredThe mirror and mount behind the mirror are rigid bodiesThe mount below the mirror acts as a torsional spring55
3.13/4.13 - Testbed Vibrational ModelLimitations: Does not consider effects of vibration on othercomponents and damping terms are assumed Only Strehl effects modelled, not effects onZernike amplitudes56
3.13/4.13 - Testbed Vibrational ModelTest ConditionsResultsConclusions: Unlikely to see harmonic forcing of the systemGain in Strehl ratio change is small so vibrationis not expected to be a significant factor inwavefront error noise levelsThe model is likely inappropriate due to lack ofmodelling damping effects of slop in systemFrequency gain response of change in Strehl ratio57
3.14/4.14 - Sensor Teensy Timing ModelCritical Factors:In order to meet the customer's requirement to sense up to 300 Hz vibrations the system must transmitdata at 1000 Hz. It is important to ensure that this rate is attainable with reasonable margin to allow themicrocontroller to handle other necessary tasks.Results: Worst case (temperature acceleration reading) cycle time must be within 1ms requirementFraction of cycle time spent sampling from sensors – 10%Fraction of cycle time spent transmitting data to the computer – 5%85 percent margin allows for necessary operations such as changing slave devices, sending framingbytes, and performing computations with the microcontrollerModel details on followingslide58
3.14/4.14 - Sensor Teensy Timing ModelTotal period sums to 1 ms for1000 Hz sampling frequency59
3.15/4.15 - Data Rate Testing Serial Read Data Rates were constructed using Pythonwith pyserial, Windows 10, and a Teensy 3.6. For Data checking, the Teensy had been set to countfrom 0 to 99 endlessly while streaming the data overserial. The data was detected to have zero errors. Tests were run with varying time intervals of 1, 5, 8, 10,12, 20, 30, 40, 50, and 60sSerial Testing ResultsAverage Data Total Number Total TimeRate: [kBps] of Bytes Sent Taken: c SPI Device Testing ResultsAverageAverage 48- Total NumberTestsSwitching bit Read Time of SwitchesConductedTime [µs][µs]and Reads0.510412.97646557210 SPI testing was completed with two genericaccelerometers, testing read time and the timerequired to switch between sensors60
3.15/4.15 - Data Cycle Test1 Cycle, Δ𝑡 1𝑚𝑠Actual System Cycle:1 Cycle, Δ𝑡 1𝑚𝑠Previously Tested /Simulated 1𝑚𝑠0.794𝑚𝑠61
5.0 PROJECT RISKS62
5.1 - Risk AnalysisPre-Mitigation Risk AnalysisLikelihoodSeverity 1. Testbed not alignedcorrectly 2. Algorithm does notcorrectly convert RCWSimages into ZernikePolynomials 3. Dust/fingerprints/damageintroduced to opticalcomponents 6. Non-consistent thermaland vibrational effects createinconsistent results63
5.1 - Risk Analysis Risk 1: Testbed not aligned correctly Severity: 5 Likelihood: 3Total: 15Description: Testbed may not align correctly, producing unintended errors in the wavefrontmeasurement and overall failure of our projectMitigation options:––– Response if risk occurs:–– Large amount of time spent planning and 3D modeling before system is builtWrite a detailed alignment procedureCareful assembly of the entire system according to planRealign the systemLook into alignment measurement devicesSeverity: 5Other risks detailedin back-up slidesPost Mitigation Risk AnalysisLikelihood: 2Total: 1064
5.1 - Risk AnalysisPre-Mitigation Risk AnalysisLikelihoodSeverity 1. Testbed not alignedcorrectly 2. Algorithm does notcorrectly convert RCWSimages into ZernikePolynomials 3. Dust/fingerprints/damageintroduced to opticalcomponents 6. Non-consistent thermaland vibrational effects createinconsistent results65
5.1 - Risk AnalysisPost-Mitigation Risk 8,119,12 1. Testbed not alignedcorrectly 2. Algorithm does notcorrectly convert RCWSimages into ZernikePolynomials 3. Dust/fingerprints/damageintroduced to opticalcomponents 6. Non-consistent thermaland vibrational effects createinconsistent results66
6. VERIFICATION AND VALIDATION67
6.1 - Optical Alignment SensitivityPurpose: Validate optical alignment sensitivities on Zernikes given by the optical path model in Zemax.Equipment: All optical components, image source, SHA, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Change orientations of M1 to check sensitivities of M1misalignment on Zernikes Change orientations of M2 to check sensitivities of M2misalignments on Zernikes68
6.2 - RCWS ImageryPurpose: Validate RCWS defocus locations are proper with no spillage and enough capture area to calculateZernikes.Equipment: All optical components, image source, RCWS, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Produce RCWS imagery at fore- and aft-focuspositions for initial and final experimental rotarypositions of M2 Check for spillage and that software can produceZernikes69
6.3 - Wavefront Sensor Read-out NoisePurpose: Determine baseline noise levels of the RCWS and SHA within the shroud.Equipment: SHA, RCWS, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Conduct zero-light tests within the shroud with variedexposure times for all seven octaves of light capture70
6.4 - RCWS Defocus SensitivityPurpose: Characterize sensitivity of Zernike read-out to non-ideal RCWS defocus.Equipment: All optical components, RCWS, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Produce initial fore-focus image from RCWS Produce Zernike sensitivities to non-ideal aft-focusposition imagery Compare to forward-predictive model71
6.5 - Power to Wavefront SensorsPurpose: Characterize exposure effect on signal to ensure power requirement.Equipment: All optical components, RCWS, SHA, image source, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Vary exposure times from RCWS and SHA todetermine saturation cap (if reached) andcharacterize signal curve with respect to exposure72
6.6 - Post-Pinhole WavefrontPurpose: Determine if the wavefront post-pinhole is spherical.Equipment: Image source, shroud, PCLocation: SwRI LabDark Room Required? YesTasks: Produce SHA imagery and calculate Zernikes tovalidate spherical wavefront post-pinhole73
6.7 - Vibrational EffectsPurpose: Obtain more accurate information about component vibrational responses.Equipment: Mirror mounts, sensor mounts, shaker table, accelerometers, shroud, PCLocation: ECAE BasementDark Room Required? NoTasks: Measure differential accelerations between top andbottom of each mount on shaker table Apply several different forcing's to retrieve a curve onthe max deflection effects74
6.8 - Environmental Sensor PerformancePurpose: Validate the performance of the environmental sensors.Equipment: Temperature sensors, accelerometers, PCLocation: ECAE BasementDark Room Required? NoTasks: Check operability of 12 sensors by running for threehours Check operability of Teensy 3.6 with timing andloading with 12 sensors75
7. PROJECT PLANNING76
7.1 - Organizational Chart77
7.2 - Work Breakdown Structure78
7.3 - Work Plan79
7.3 - Work Plan80
7.4 - Cost Plan81
7.5 - Test Plan82
QUESTIONS?83
REFERENCES84
[1] RS2000 Precision Tuned Damped Research Optical Tables. Newport, 4 Dec. al-tables.[2] “ASI120MM (Mono).” ZWO ASI, ZWO Company, 29 July 2015, 0mm/.[3] “QHY174M/C.” QHY174, QHYCCD, www.qhyccd.com/QHY174.html.[4] “PT1-Z8 - 25 Mm (0.98’) One-Axis Motorized Translation Stage, 1/4’-20 Taps.” Thorlabs, Thorlabs, Inc.,www.thorlabs.com/thorproduct.cfm?partnumber PT1-Z8.[5] Analog Devices, “Ultralow Power Digital MEMS Accelerometer”, ion/data-sheets/ADXL344.pdf, ADXL344 datasheet, 2012[6] Analog Devices, "16-Bit Digital SPI Temperature Sensor", ion/data-sheets/ADT7320.pdf, ADT7320 datasheet, 2012[7] “WFS150-7AR - Shack-Hartmann WFS, 150 Μm Pitch, AR Coated: 400 - 900 Nm.” Thorlabs, Thorlabs,Inc., www.thorlabs.com/thorProduct.cfm?partNumber WFS150-7AR.85
BACKUP SLIDES86
Table of Contents Project Purpose andObjectives Design Solution––––––Image SourceOptical SystemWavefront SensorsEnvironmental SensorsTestbedTest Software CPE/Design Requirements––––––ImageOptical SystemRCWSAlgorithm and SoftwareThermal/Vibration ModelTeensy Model Project Risks Verification and Validation Project Planning87
Image Source88
Zernike Space Characteristics:– A complete set of orthogonalpolynomials that arise in theexpansion of a wavefront function foroptical systems with circular pupils.– Happen to have the samecharacteristics that images have; theuse of Zernike polynomials are anapproximate analytical description ofthe optical wavefront– Represented as an infinite series, butthe first 11 terms are suffici
2.3 - Wavefront Sensors Purpose: The wavefront sensors are the test articles for the experiment. Requirements: A Shack-Hartmann Array sensor from Thorlabs will be provided A Roddier Curvature Wavefront Sensor must be developed using COTS components Shack-Hartmann Array: Roddier Method: 22
It can compensate the wavefront distortion caused by the following amplification and transmission. The Shack Hartmann wavefront sensor (Thorlabs WFS150-5C) is placed at the end to measure the output wavefront distribution. The cavity mirror position is the image relay plane. The DM and the Shack Hartmann wavefront sensor are both at the Figure 1.
Min Longitude Error: -67.0877 meters Min Altitude Error: -108.8807 meters Mean Latitude Error: -0.0172 meters Mean Longitude Error: 0.0028 meters Mean Altitude Error: 0.0066 meters StdDevLatitude Error: 12.8611 meters StdDevLongitude Error: 10.2665 meters StdDevAltitude Error: 13.6646 meters Max Latitude Error: 11.7612 metersAuthor: Rafael Apaza, Michael Marsden
a given wavefront sensor is the primary goal of the AWESoMe testbed. Figures 1 and 2 provide a visual representation of the method for measuring the wavefront errors as well as the physical hardware required to do so. 2.2.Roddier Curavture Wavefront Sensor Because the RCWS method is relatively new compared to the Shack-Hartmann array method .
Bruksanvisning för bilstereo . Bruksanvisning for bilstereo . Instrukcja obsługi samochodowego odtwarzacza stereo . Operating Instructions for Car Stereo . 610-104 . SV . Bruksanvisning i original
The pyramid wavefront sensor (1996 by Ragazzoni)6 is a pupil plane wavefront sensor that in e ect works as a 2-D Foucault knife-edge test. In commonly used con gurations, the focal plane . and OCAM2K were mounted on a coaxial rail system from ThorLabs. Custom mounting plates
Coded Wavefront Sensor: Analogy!12 [Ng et al. 2005] Lenslet light field camera [Veeraraghavan et al. 2007, Marwah et al. 2013] Mask-based light field cameras [Wang et al. 2017] Coded wavefront sensor [Shack and Platt 1971] Shack-Hartmann wavefront sensor
WISHED: Wavefront imaging sensor with high resolution and depth ranging Yicheng Wu , Fengqiang Li , Florian Willomitzer, Ashok Veeraraghavan, Oliver Cossairt Abstract—Phase-retrieval based wavefront sensors have been shown to reconstruct the complex field from an object with a high spatial resolution.
Super Locrian is often used in jazz over an Altered Dominant chord (b9, #9, b5, #5, #11, b13) Melodic Minor w h w, w w w h 1 w 2 h b3 w 4 w 5 w 6
