Current-division-type variable spatial filtering detector with multi-valued weighting functions

This paper presents a new type of two-dimensional spatial filtering detector (SFD) with variable weighting function and multiple weight values. This SFD was realized by the current-division method. To achieve the new SFD with variable and multi-valued weighting functions, the weighted-sum structure is used. R-2R ladder circuits are applied to realize current-division-type multi-valued weighting as dividing currents from a photodiode pixel. The digital memories are also used for achieving variable weight values. The weighted output signals of each of the photodiodes are summed up in one signal. We manufacture the current-division-type variable spatial filtering detector with multi-valued weighting functions (VSFDwMWF). Experiments show that VSFDwMWF can be operated as an SFD with basic characteristics and example results of weighting function setting.