Pixel-level mapping method in high dynamic range imaging system based on DMD modulation

In order to build pixel-to-pixel correspondence between the CCD camera and digital micromirror device (DMD) in high dynamic range (HDR) imaging system, we proposed an absolute phase mapping method based on the first partial derivatives of phase-shifted composite fringes in this paper. Compared with the conventional phase mapping method, the needed fringe patterns of our method are reduced by one time, which improves the mapping efficiency. Meanwhile, experimental results show the proposed method has an accuracy improvement over the existing methods. The root mean square error is within 0.11 pixels in both the horizontal and vertical directions, reaching the sub-pixel mapping accuracy and indicating the superiority of our method. Finally, we combined the proposed mapping method with the imaging system and achieved high dynamic range imaging by photographing the surface of highlighted object, which verified the validity and practicability of our method. •A novel phase mapping method is proposed based on phase-shifted composite fringes.•The phase mapping efficiency is increased by 50%.•The average mapping pixel deviation is 0.13 pixel, reaching the sub-pixel accuracy.•Pixel-level precise modulation imaging based on DMD for HDR scenes is achieved.