A system, apparatus, and method for analyzing photon emission data to discriminate between photons emitted by transistors and photons emitted by background sources. The analysis involves processing of integrated circuit computer aided design data to identify transistors within the CAD data. The analysis may further involve the use of Boolean operators to process the CAD data to particularly identify, such as through a channel, the location of the NMOS and PMOS gates, the location of the drain and source, or some combination of the location of the gate and drain or source to particularly identify the pinch-off region.