Image Processing in Differential Digital Holography (DDH)

Accumulating dust on Charge-Coupled Device/Complementary Metal-oxide-Semiconductor (CCD/CMOS) sensors can cause problems in detecting defects on observed object in some industrial production. This paper describes Differential Digital Holography (DDH) and observed effect of cancelling the negative impact of dust on optical sensor. The laboratory setup for recording digital holograms is described and shown graphically later in paper. Differential digital holography method is presented step by step. Furthermore, negative effect of accumulating dust on CCD/CMOS sensor and cancelling effect due to DDH method is explained. DDH method comprises of both hardware and software parts. Digital hologram recording process takes place on hardware and all image, i.e., digital hologram, while processing is performed by intensive calculations on processor. Experiments were conducted and graphical results are shown.