Fig. 2.

Synchronization of the CMOS and DLP and construction of a confocal image by averaging two complementary images. Imaging configuration I in (a) shows the spatiotemporal coordination of the DLP illumination lines with the CMOS rolling shutter aperture; the discrete nature of DLP scanning combined with the continuous sequential readout of CMOS rows introduces nonuniform exposure among the rows, as revealed in configuration I in (c) and the corresponding image (d). A complementary image (e) can be acquired by shifting the exposure distribution by $D/2$ in configuration II in (b). A confocal image without illumination artifacts is then constructed by averaging two complementary frames, as shown in (d), (e), and (f). Lens paper was imaged as a target. $D$, number of rows in the detection aperture; $T_s$, CMOS exposure time.