Catadioptric zoom panoramic annulus optical system and design method thereof

The invention relates to a catadioptric zoom panoramic annulus optical system and a design method thereof, belongs to the technical field of optical system design, and aims to solve the problem that a pipeline detection system cannot realize large-view-field coarse detection and small-view-field fine detection. The method comprises the following steps: deducing a relational expression between the curvature radius of a front-end reflector and the view field angle of a zoom lens group, and determining an initial structure of the front-end reflector; the positions of a sagittal image point and a meridian image point after a certain detected point passes through the front-end reflector are obtained through derivation, the optimal image point is located between the meridian image point and the sagittal image point and is close to the one-third position of the meridian image point, and the optimal image point position of the front-end reflector is solved; fitting the optimal image points corresponding to different