提出了一种改进型Dyson光谱成像系统，以克服传统Dyson光谱成像系统焦平面探测器安置困难的缺点。首先，基于折射球面罗兰圆理论，提出了这种改进型Dyson光谱成像系统的光学设计方法。然后，利用MATLAB软件编制了初始结构参数快速计算程序。 作为实例，设计了一个相对孔径为1/2，波段为200～1 000 nm的Dyson光谱成像系统。利用自己编制的MATLAB程序计算了初始结构参数，利用光学设计软件ZEMAX-EE对该光谱成像系统进行了光线追迹和优化设计，并对设计结果进行分析。分析结果表明，在整个工作波段(200～1 000 nm）内，点列图半径均方根值小于4.2 μm，实现了大相对孔径宽波段像散同时校正，在宽波段内同时获得了良好的成像质量，满足设计指标要求。得到的结果验证了所提出的光学设计方法是可行的。

A modified Dyson spectral imaging system was proposed to overcome the problems that the focal plane detector is hard to be arranged in a classical Dyson spectral imaging system. Firstly, the optical design method of the modified Dyson spectral imaging system was developed based on the Rowland circle theory of refractive spherical surface. Then, the initial parameter computing program was programmed using MATLAB software. As an example, a Dyson spectral imaging system operating in 200-1 000 nm with a relative aperture 1/2 was designed. The initial parameters were computed using proposed MATLAB program, and the ray tracing and optimization for the spectral imaging system were performed with ZEMAX-EE sofware. The analyzed results demonstrate that the Root Mean square(RMS) of a spot radius is less than 4.2 μm in the whole working waveband (from 200 nm to 1 000 nm), which implements astigmatism correction and obtains a good imaging quality in a wide spectral region and a large relative aperture. These results prove the feasibility of the optical design method proposed.