The optical-mechanical model of the off-axis optical system with oscillating mirror is established. The stray light path is analyzed on the basis of the simulation results. According to various types of stray light paths, the main path of stray light are determined and the influence of important surfaces and illumination surfaces on stray light of the camera are clarified. Effective restraint measures are proposed without blocking the imaging light. After re-simulation, the veiling glare indexes of the two imaging channels are greatly reduced. PST (Point Source Transmittance) is used as an index to test the validity of stray light suppression measures. When the off-axis angle is 30 degrees, the PST of the camera reaches 10-8, which meets the design requirements.
The resolution and observing width of optical remote sensing camera can be enhanced by increasing the detector length of focal plane. Optical butting is used to increase the imaging length owing to its simple structure, low cost and the simultaneously-imaging detectors. But butting process is influenced by many factors, which result in imaging gaps, so overlapping pixels between adjacent detectors is the key. In this paper, the factors causing imaging gap are analyzed, and calculation of overlapping pixel number is given out based on the analysis. Firstly an optical-butting focal plane system is built on optical imaging principles. Then the factors causing imaging gap are listed and analyzed, under the consideration of telecentric and non-telecentric optical system. Based on the imaging gap analysis, a formula for overlapping pixel number calculation is obtained, with the MTF assurance in vignetting districts resulted from optical butting. Finally a calculation example of a camera is given.