Opto-Electronic Engineering, Volume. 50, Issue 7, 230040(2023)
Study of off-axis telescope misalignment correction method using out-of-focus spot
Figures & Tables(18)
Fig. 2. General implementation process of the method in this paper
Fig. 4. Wavefront statistics of misaligned samples. (a) Wavefront PV statistics; (b) Wavefront RMS statistics
Fig. 5. Test sample wavefront Information Statistics. (a) Wavefront PV statistics; (b) Wavefront RMS statistics
Fig. 6. Wavefront PV statistics after correction. (a) Sensitivity matrix method; (b) Defocus −15 mm; (c) Defocus −10 mm; (d) Defocus −5 mm
Fig. 7. Wavefront RMS statistics after correction. (a) Sensitivity matrix method; (b) Defocus −15 mm; (c) Defocus −10 mm; (d) Defocus −5 mm
Fig. 8. Statistics of correction results under 1% noise floor of the defocus −15 mm scheme. (a) Wavefront PV value statistics; (b) Wavefront RMS value statistics
Fig. 11. The average time-consuming of a single calculation on each hardware platform
Table 1. Telescope basic parameters table
View tableView in ArticleTable 1. Telescope basic parameters table
Parameter name Focal distance/mm F-number Caliber/mm Working wavelength/nm Parameter value 2427.12 16.3805 148 532
Table 2. Parameters of the telescope reflector
View tableView in ArticleTable 2. Parameters of the telescope reflector
Surface Mechanical diameter/mm Radius of curvature/mm Interval/mm Conic factor Off-axis parameters/mm Primary mirror 148 −1200 −480 −1 210 Secondary mirror 60 −240 260 −1 42
Table 3. Coefficient and distribution of the out-of-focus term
View tableView in ArticleTable 3. Coefficient and distribution of the out-of-focus term
−15 mm −10 mm −5 mm Defocus term coefficient −5.580 −3.307 −1.844 Coefficient distribution/φ [−7.0875, −3.8361] [−5.2038, −1.9909] [−3.3399, −0.1329] Coefficient distribution/φ' [4.0725, 7.3239] [1.4102,4.6231] [0.3471,3.5541]
Table 4. Summary table of network parameters
View tableView in ArticleTable 4. Summary table of network parameters
Parameter name Parameter Block stacked structure [2, 2, 4, 2] Loss function MSE Loss Optimizer AdamW Initial learning rate 10E-6 Training times 2000
Table 5. Hartmann parameter table
View tableView in ArticleTable 5. Hartmann parameter table
Technical parameters Value Technical parameters Value Aperture dimension 5.2 mm×7 mm Repeatability/rms <lambda/200 Number of sub-apertures dedicated for analysis 16×20 Wavefront measurement accuracy in absolute mode/rms Maximum between ~ lambda/100 and 6 nm Tilt dynamic range >±3°(600 lambda) Max acquisition frequency 20 Hz
Table 6. Predicted value and truth table of random misalignment
View tableView in ArticleTable 6. Predicted value and truth table of random misalignment
True value / Predictive value Group 1 Group 2 Group 3 Group 4 Group 5 Dx/mm 0.499 / 0.500 0.491 / 0.496 0.088 / 0.086 0.299 / 0.313 −0.472 / −0.471 Dy/mm −0.312 / −0.325 0.101 / 0.104 0.293 / 0.287 −0.323 / −0.328 0.427 / 0.428 Tx/degree 0.063 / 0.057 0.012 / 0.012 −0.114 / −0.113 0.053 / 0.450 −0.121 / −0.120 Ty/degree 0.128 / 0.124 0.118 / 0.118 −0.067 / −0.066 −0.134 / −0.113 0.078 / 0.074
Table 7. Statistical table of prediction misalignment residual data
View tableView in ArticleTable 7. Statistical table of prediction misalignment residual data
ΔDx/mm ΔDy/mm ΔTx/degree ΔTy/degree Maximum 0.0194 0.0147 0.0170 0.0198 Minimum 2.599E-5 2.099E-5 1.100E-5 1.800E-5 Average 0.0072 0.0045 0.0037 0.0055 Standard deviation 0.01421 0.00594 0.00557 0.01028
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Siheng Tian, Yongmei Huang, Yangjie Xu, Xinyuan Nan, Qiongyan Wu, Chunsheng Xiang, Wei Tang. Study of off-axis telescope misalignment correction method using out-of-focus spot[J]. Opto-Electronic Engineering, 2023, 50(7): 230040
Paper Information
Category: Article
Received: Feb. 23, 2023
Accepted: Apr. 11, 2023
Published Online: Sep. 25, 2023
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