Abstract: The Trigonometric-function operator is put forward as a novoel image segmentation arithmetic. It is deduced by the principle of optical interference and applied in fast image segmentation. The hardware of Trigonometric-function operator is analyzed. The pseud phase of input image is important for the operator and need to be translated from the intensity distribution by appropriate conversion rule. Various conversion manners are defined, including linearity, logarithm function, tangent function and arc tangent function. Numerical simulation results show that image segmentation effects of trigonometric-function operator vary with the manners of intensity-pseud phase translation and their parameters. When logarithm sigmoid tranfer function is used as intensity-phase conversion manner, the tri