Research On High Dynamic Range Imaging Technology With Digital Micromirror Device

Dynamic range is one of the most important characters in photoelectric imaging equipment.Generally,dynamic range of photoelectric imaging equipment can reach 48 db.It is difficult to satisfy the space target imaging detection,while imaging science application require more than100 db.How to improve the dynamic range of imaging system is one of the optical detection imaging equipment's key issues to be solved.To solve the problem,multiple exposures fitting method still has limitations.But optical modulation before imaging technology is a good solution in real time and on line,which has many advantages and broad application prospects.It becomes the research hotspot in the field of machine vision.Using DMD in optical modulation,which can make visual measuring system realize more flexible range of visual space,wider dynamic range and higher accuracy of measurement and measuring efficiency.This paper proposes a high dynamic adaptive imaging system based on DMD,main research contents including:Set up DMD high dynamic range imaging system.Analyzing DMD structure and the working situation,basing its working principle,put forward a kind of DMD high dynamic range imaging system.Design optical path system,select the lens model,carry on the shell design and implement encapsulation,succeeded in building a new generation of DMD camera.Research the system correction and internal algorithm.Match and correct system with moire fringe method,to achieve a good match.Calibrate system with Harris.In view of high precision mapping problem based on the DMD and CCD imaging system of,put forward the DLT direct linear algorithm,a nonlinear polynomial distortion fitting algorithm and BP neural network algorithm.The three algorithms of matching can all be achieved through experiment,while the polynomial algorithm has better precision.It can make the final error correction in 1.02 pixels,meeting the needs of mapping at pixel level.Study high dynamic range imaging.To achieve the adaptive high dynamic imaging,it will be able to control the DMD each mirror's deflection.Including fixed step method,adaptive space design method,the mask area method,choose mask area method to control DMD.In order to achieve the purpose of adaptive control,choose PID control.Design reasonable system PID control,through the parameters setting,to get the adaptive mask generation scheme.According to this formula,upload mask,to generate the adaptive high dynamic image.