Optical System Design of an Integrated Dual-Line-Array Mapping Camera Based on Differential Evolution

Dual-line-array mapping cameras acquire remote sensing images with stereo geometry and serve as important payloads for obtaining high-precision three-dimensional surface information in applications such as topographic mapping, urban planning, and resource surveys. To address the strong dependence on experience, complex parameter adjustments, and susceptibility to local optima associated with the gradual conversion of coaxial configurations into off-axis configurations in conventional reflective system design, a method is proposed for directly searching for an initial configuration in the final off-axis operating state. The method constructs a merit function that accounts for both imaging performance and structural constraints and uses the differential evolution algorithm to globally search the system configuration parameters, yielding an off-axis initial configuration with favorable overall performance. Based on this method, an optical system is designed for an integrated dual-line-array mapping camera with a focal length of 9034 mm, an F-number of 11, a field of view of 5.6° × 0.5°, and a convergence angle of 25°. The initial configuration obtained by the algorithm is imported into software for verification. Its maximum RMS spot radius is 26.636 μm, and the maximum absolute distortion over the full field of view is 0.013% for both channels, referenced to the central field of each channel, providing an effective starting point for subsequent optimization. XY polynomial freeform surfaces are then introduced, and the system is optimized with constraints on image-space telecentricity and structural dimensions. The optimized system exhibits good imaging quality, with an MTF greater than 0.28 at 72 lp/mm over the full field of view of both channels and a maximum absolute distortion below 0.4%, referenced to the central field of each channel. Tolerance analysis is also performed, and the results verify the effectiveness of the proposed direct initial-configuration search method and its design procedure. No experimental testing has yet been conducted; the conclusions are therefore limited to feasibility demonstrated by simulation.