A 37-element solar adaptive optics （AO） system was built and installed at the 26-cm solar fine structure telescope of Yunnan Astronomical Observatory. The AO system is composed of a fine tracking loop with a tip/til...A 37-element solar adaptive optics （AO） system was built and installed at the 26-cm solar fine structure telescope of Yunnan Astronomical Observatory. The AO system is composed of a fine tracking loop with a tip/tilt mirror and a correlation tracker, a high-order correction loop with a 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor based on the absolute difference algorithm, and a real time controller. The system was completed on Sep. 28, 2009 and was used to obtain AO-corrected high-resolution solar images. The contrast and resolution of the images are clearly improved after wavefront correction by AO. To the best of out knowledge, this system is the first solar AO system in China.展开更多
We propose a sub-aperture stitching algorithm based on a frequency domain that can be denoted as a power spectral density （PSD）. Our algorithm is verified by the experimental data obtained from measuring a epl.23 m ...We propose a sub-aperture stitching algorithm based on a frequency domain that can be denoted as a power spectral density （PSD）. Our algorithm is verified by the experimental data obtained from measuring a epl.23 m mirror at the Changchun Institute of Optics, Fine Mechanics and Physics. Then, we apply it to the Great Steer- ing Science Mirror （GSSM） of the Thirty Meter Telescope （TMT） with the simulated data before the preliminary design phase, and obtain a more objective result on the frequency domain aberrations. Therefore, the sub-aperture stitching-based PSD is expected to be useful for specifying a large aperture mirror surface for mirror vendors.展开更多
This paper presents a modified multi-resolution telescopic search algorithm (MRTlcSA) for the block-matching motion estimation. A novel inverse telescopic search is substituted for the conventional telescopic search, ...This paper presents a modified multi-resolution telescopic search algorithm (MRTlcSA) for the block-matching motion estimation. A novel inverse telescopic search is substituted for the conventional telescopic search, that reduces the on-chip memory size and memory bandwidth for VLSI implementation. In addition, strategies of motion track and adaptive search window are applied to reduce the computational complexity of motion estimation. Simulation results show that, compared with the MRTleSA, the proposed algorithm reduces the computational load to only 30% while preserving almost the same image quality. Comparisons on hardware cost and power consumption of the VLSI implementations using the two algorithms are also presented in the paper.展开更多
A novel lens system with correction of secondary spectrum without using anomalous glasses is presented. The lens system comprises four separated lens components, with three of them being subapertures. Two examples of ...A novel lens system with correction of secondary spectrum without using anomalous glasses is presented. The lens system comprises four separated lens components, with three of them being subapertures. Two examples of apochromatic telescope are presented, both with the use of typical normal glasses, namely crown K9 and flint F5 glasses, and low-cost slightly anomalous dispersion glasses. Secondary spectrum and other chromatic aberrations of the two design examples are corrected.展开更多
The active control of 30-m ring interferometric telescope （RIT） needs edge sensing and tip sensing when its primary mirror is composed by trapezoid-shaped segments, and the imaging performance of the RIT is determin...The active control of 30-m ring interferometric telescope （RIT） needs edge sensing and tip sensing when its primary mirror is composed by trapezoid-shaped segments, and the imaging performance of the RIT is determined by the accuracy of these two detecting approaches. Considering the detecting accuracy available in current segmented telescope active control systems, the effect of these detecting approaches on the surface error of the RIT primary mirror is calculated from the point of error propagation. The corresponding effect on imaging performance （modulation transfer functions （MTFs） and point spread functions （PSFs） at several typical wavelengths） of the RIT primary mirror is also simulated. The results show that tip sensing is very important for increasing the active control quality of the RIT primary mirror under the present techniques.展开更多
A 127-element adaptive optical system has been developed and integrated into a 1.8-m astronomical telescope in September 2009.In addition,the first light on a high-resolution imaging for stars has been achieved（Septe...A 127-element adaptive optical system has been developed and integrated into a 1.8-m astronomical telescope in September 2009.In addition,the first light on a high-resolution imaging for stars has been achieved（September 23,2009）.In this letter,a 127-element adaptive optical system for 1.8-m telescope is described briefly.Moreover,star observation results in the first run are reported.Results show that the angular resolution of the system after adaptive optics correction can attain 0.1 arcsec,which approaches the diffraction limit of 1.8-m telescope at 700-900 nm band.展开更多
文摘A 37-element solar adaptive optics （AO） system was built and installed at the 26-cm solar fine structure telescope of Yunnan Astronomical Observatory. The AO system is composed of a fine tracking loop with a tip/tilt mirror and a correlation tracker, a high-order correction loop with a 37-element deformable mirror, a correlating Shack-Hartmann wavefront sensor based on the absolute difference algorithm, and a real time controller. The system was completed on Sep. 28, 2009 and was used to obtain AO-corrected high-resolution solar images. The contrast and resolution of the images are clearly improved after wavefront correction by AO. To the best of out knowledge, this system is the first solar AO system in China.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant No.11403022
文摘We propose a sub-aperture stitching algorithm based on a frequency domain that can be denoted as a power spectral density （PSD）. Our algorithm is verified by the experimental data obtained from measuring a epl.23 m mirror at the Changchun Institute of Optics, Fine Mechanics and Physics. Then, we apply it to the Great Steer- ing Science Mirror （GSSM） of the Thirty Meter Telescope （TMT） with the simulated data before the preliminary design phase, and obtain a more objective result on the frequency domain aberrations. Therefore, the sub-aperture stitching-based PSD is expected to be useful for specifying a large aperture mirror surface for mirror vendors.
文摘This paper presents a modified multi-resolution telescopic search algorithm (MRTlcSA) for the block-matching motion estimation. A novel inverse telescopic search is substituted for the conventional telescopic search, that reduces the on-chip memory size and memory bandwidth for VLSI implementation. In addition, strategies of motion track and adaptive search window are applied to reduce the computational complexity of motion estimation. Simulation results show that, compared with the MRTleSA, the proposed algorithm reduces the computational load to only 30% while preserving almost the same image quality. Comparisons on hardware cost and power consumption of the VLSI implementations using the two algorithms are also presented in the paper.
文摘A novel lens system with correction of secondary spectrum without using anomalous glasses is presented. The lens system comprises four separated lens components, with three of them being subapertures. Two examples of apochromatic telescope are presented, both with the use of typical normal glasses, namely crown K9 and flint F5 glasses, and low-cost slightly anomalous dispersion glasses. Secondary spectrum and other chromatic aberrations of the two design examples are corrected.
基金supported by the National Natural Science Foundation of China(Nos.10573035,10533040)the National "973" Program of China(No.2006CB806300).
文摘The active control of 30-m ring interferometric telescope （RIT） needs edge sensing and tip sensing when its primary mirror is composed by trapezoid-shaped segments, and the imaging performance of the RIT is determined by the accuracy of these two detecting approaches. Considering the detecting accuracy available in current segmented telescope active control systems, the effect of these detecting approaches on the surface error of the RIT primary mirror is calculated from the point of error propagation. The corresponding effect on imaging performance （modulation transfer functions （MTFs） and point spread functions （PSFs） at several typical wavelengths） of the RIT primary mirror is also simulated. The results show that tip sensing is very important for increasing the active control quality of the RIT primary mirror under the present techniques.
文摘A 127-element adaptive optical system has been developed and integrated into a 1.8-m astronomical telescope in September 2009.In addition,the first light on a high-resolution imaging for stars has been achieved（September 23,2009）.In this letter,a 127-element adaptive optical system for 1.8-m telescope is described briefly.Moreover,star observation results in the first run are reported.Results show that the angular resolution of the system after adaptive optics correction can attain 0.1 arcsec,which approaches the diffraction limit of 1.8-m telescope at 700-900 nm band.
