Research On Infrared Imaging Technology Based On Prism Scanning With Wide Field And High Resolution

For any optical system,the two important performance indicators are the field of view and the imaging resolution,such optical system which can work with a large field of view while still obtaining clear and detailed images has favored by more and more fields.However,for a conventional optical system,it is generally necessary to use a detector with higher resolution or a camera with better imaging performance to meet above two imaging requirements at the same time,but this will greatly increase the cost.Rotating double prism beam scanning technology uses the rotation of two prisms around the optical axis to control the orientation of the outgoing beam to obtain a field of view in different spaces.This technology has significant advantages in simplifying the system structure,reducing the system size,and performing fast,high-precision and large-area scanning.Therefore,in combination with a rotating double prism and the use of a back-end infrared high-resolution imaging system,it is possible to avoid a substantial increase in cost,while achieving wide-field work requirements and obtaining high-resolution images.Starting from the rotating double prism system,the subject design an achromatic rotating double prism system for the chromatic aberration caused by the prism,and correct the distortion caused by the prism,finally use image reconstruction technology to achieve wide field of view and high-resolution imaging target.First,by analyzing the working principle of the rotating double prism,the cause of the chromatic aberration is clarified,and the scheme to eliminate the chromatic aberration is determined.According to the given design index,a group of prism materials used for this index is determined,and according to this group of materials,the reverse optical path of the rotating double prism is analyzed,and the relationship between the incident angle,chromatic aberration and the wedge angle of the prism is determined by algorithm drawing.The wedge angle of the prism is determined according to the design index.The rotating double prism structure with the determined parameters is drawn on the optical design software,and the point diagram,MTF,PSF and vertical axis chromatic aberration of the system are analyzed.The results show that the designed rotating double prism structure meets the design specifications and can effectively eliminate chromatic aberration.Then,in view of the distortion caused by the rotating double prism,the relevant parameters of the rotating double prism are obtained using the design results of the software,and the prism distortion function is established,and the imaging model of the entire optical system is constructed by combining with the parameters of the infrared high-resolution imaging system.At the same time,the optical system is used to shoot the picture of bitmap to extract the pixel coordinates of every point,and the actual coordinates of each point are obtained.Then,with using the LM algorithm,the model's unknown parameters are solved,and finally the image distortion is corrected.The undistorted image is reconstructed using image registration and stitching algorithms,and obtain a wide field of view image.Finally,the scanning trajectory of the outgoing beam of the rotating double prism system is analyzed.In order to make the scanning blind area as small as possible,the size of the same area included in the instantaneous field of view is appropriate,and the scanning time is as short as possible,select and optimize the appropriate scanning method of the rotating double prism system,and it can achieve the desired effect.