曲面复眼中对数型锥透镜成像特性研究

Imaging characteristics of logarithmic axicon for application in compound eye system

提出利用对数型锥透镜的焦线特性解决球面复眼系统成像过程中球透镜离焦问题。设计锥透镜焦深范围满足复眼系统各个子眼通道成像。通过仿真分析,研究了对数型锥透镜的轴上与离轴成像特性;利用金刚石切削技术和翻模技术实现该锥透镜的批量制造。实验检测结果表明,锥透镜焦线范围内轴上成像光斑直径保持一致;离轴成像时产生的十字光斑,可以通过提取交叉点,确定复眼系统子眼通道离轴成像光斑中心位置。该设计方案可用于消除球透镜固有离焦发散现象,提高复眼中各子眼对其视场内各方向光线成像光斑中心的定位精度,有效改善复眼成像质量。

Logarithmic axicon（LA） was proposed to overcome the defocus in the spherical compound eye imaging utilizing its focal line. The depth of field of LA was designed to meet the requirements of all the channels of the compound eye. On-axis and off-axis characteristics of LA were studied based on numerical simulation. Mass production of LA was achieved by diamond cutting and molding technology.Experimental results show that the on-axis point spread function（PSF） keeps constant along the propagation, while the off-axis PSF is cross-shaped. The intersection of the cross can be extracted and used to determine the spot centroid in off-axis imaging. The proposed method is helpful to eliminate the intrinsic defocus effects of spherical lens and improve the positioning accuracy and imaging quality of the spherical compound eye system.