Infrared and Laser Engineering, Volume. 51, Issue 12, 20220238(2022)
Defocus diagnosis method of LAMOST spectrograph based on multi-object image definition evaluation
Figures & Tables(14)
Fig. 2. A part of the LAMOST spectrometer calibration lamp spectrum
Fig. 3. (a) Normal spots; (b) Pixel depth distribution curve about normal spots in the
Fig. 5. (a) Fitting comparison of normal spots in the
Fig. 6. (a) FWHM distribution of all spots under the normal condition; (b) FWHM distribution of all spots in the defocus
Fig. 9. Comparison diagram of normalized image definition evaluation curve
Table 1.
R 2 of three types of spots under the different terms of four functional modelsView tableView in ArticleTable 1.
R 2 of three types of spots under the different terms of four functional modelsFunction model R2 of three types of spots Normal Slightly defocus Excessively defocus Fourier 1 0.91 0.97 0.82 2 0.98 0.98 0.98 3 0.99 0.98 0.98 Polynomial 1 0.02 0 0 2 0.52 0.73 0.82 3 0.59 0.73 0.83 Sum of sine 1 0.62 0.80 0.82 2 0.98 0.97 0.95 3 0.99 0.98 0.98 GMM 1 0.98 0.97 0.76 2 0.98 0.98 0.98 3 0.99 0.98 0.98
Table 2. FWHM values of three types of spots under four functional models
View tableView in ArticleTable 2. FWHM values of three types of spots under four functional models
Spot type FWHM theoretical value Function model GMM Fourier Sum of sine Polynomial Normal 5.4 5.3 5.2 4.9 9.4 Slightly defocus 6.5 6.4 6.6 6.6 8.4 Excessively defocus 10.6 10.1 10.4 10.4 11.3
Table 3. The number of spots identified by spectra at different defocus amount
View tableView in ArticleTable 3. The number of spots identified by spectra at different defocus amount
Defocusing distance/μm 0 25 50 100 125 150 175 Number of spots 553 544 537 468 402 251 150
Table 4. The comparison of image definition function evaluation criterion
View tableView in ArticleTable 4. The comparison of image definition function evaluation criterion
Method R MSE α β Roberts 1.41 0.18 0 3 DCT 1.67 0.55 0 3 Entropy 1.04 0.86 2 Vollaths 2.23 0.22 0 2 Multi-objective 108.30 0.17 0 3
Tools
Get Citation
Copy Citation Text
Xiaojie Zhang, Wei Wei, Yonghui Hou, Yong Zhang, Hangxin Ji, Xiaofei Li, Qishuai Lu, Kang Huang, Yuyao Liu. Defocus diagnosis method of LAMOST spectrograph based on multi-object image definition evaluation[J]. Infrared and Laser Engineering, 2022, 51(12): 20220238
Paper Information
Category: Image processing
Received: Apr. 7, 2022
Accepted: --
Published Online: Jan. 10, 2023
The Author Email: Wei Wei (wwei@niaot.ac.cn)
© Copyright 2018-2021 | Chinese Laser Press.
All Rights Reserved 沪ICP备15018463号-20