An optical sensor system includes a multi-color pyrometer in optical communication with a component. The pyrometer generates signals at least partially representative of radiation received from the component and from soot particles. The system includes at least one processing unit coupled to the pyrometer. The processing unit is programmed to receive the signals and distinguish portions of radiation received between at least two wavelength bands. The processing unit is also programmed to determine that a first portion of radiation within a first of the wavelength bands is representative of a temperature of soot particles and that a second portion of radiation within a second of the wavelength bands is representative of a temperature of the component. The processing unit is further programmed to filter out signals representative of the first portion of the radiation.