In this paper, structure analysis with finite element method is carried out for a 4-m class honeycomb primary mirror. The mirror's baseline support system consists of 60 axial support actuators mounted at the mirror's back surface and 42 lateral actuators. The analysis includes static structural analysis under gravity load, support system sensitivity evaluation and simulation about correction ability of force actuators. The optimized deformation of the primary mirror meets the error budget. Though we find the honeycomb primary mirror is not so sensitive to variation of support forces, the mirror figure still can be compensated by adjusting the support forces.
Three typical calibration patterns, including checkerboard, Gaussian point grid, and crossed fringe patterns, are chosen to find a good one for camera calibration. Through computer simulation and camera intrinsic parameter calibration experiment, the crossed sine fringe pattern using fringe analysis method is defined as the one with the best precision. However, the phase information is obtained by Fourier transform (FT), which cannot detect the points located in the edge of the point grid. Thus, an innovative method uses phase shifting in the fringe analysis process is proposed, it can avoid the extraction misplacement in the edge of the point grid by the FT method, and make the crossed sine fringe pattern more usable in camera calibration. The camera extrinsic parameter calibration experiment proves the effectiveness of the recent method. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)