Shiyuan YANG^* and Hiroaki TAKAJO^†

Department of Electrical Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata, Kitakyushu 804-8550, Japan

(Received October 5, 2004; Accepted January 30, 2005; Revised January 26, 2005)

An iterative speckle reduction method is proposed to reduce the speckle noise in the reconstruction of kinoforms. Because a kinoform only has phase modulation, the phase freedom of the reconstructed image is usually utilized for spectrum smoothing. We consider the speckle noise as isolated zeros among the discrete reconstructed points. An isolated zero leads to a 2π circle of the image phase differences. Our proposed iterative speckle reduction method changes the image phase to avoid the 2π circles in the reconstructed points. Computer simulations are shown to demonstrate the effect of our method.

Key words: computer-generated hologram, kinoform, speckle noise, isolated zero, 2π ambiguity, phase freedom, iterative dummy area algorithm

^*E-mail address: yang@elcs.kyutech.ac.jp
^†E-mail address: takajo@elcs.kyutech.ac.jp