Measurement of Noise Equivalent Quanta (NEQ) Using the Dead Leaves Technique

Noise Equivalent Quanta (NEQ) is an objective Fourier metric which evaluates the performance of an imaging system by detailing the effective equivalent quanta of an exposure versus spatial frequency [1]. Calculated via the modulation transfer function (MTF) and noise power spectrum (NPS), it is a valuable precursor for ranking the detection capabilities of systems and a fundamental metric that combines sharpness and noise performance of an imaging system into a single curve in a physically meaningful way.

The dead leaves measurement technique is able to provide an estimate of the MTF and NPS of an imaging system using a single target [2-7], and therefore a potentially convenient method for the assessment of NEQ. This work validates the use of the dead leaves technique to measure NEQ, firstly through simulation of an imaging system with known MTF and NPS, then via measurement of camera systems, both in the RAW domain and post-ISP. The dead leaves approach is shown to be a highly effective and practical method to estimate NEQ, ranking imaging systems performance both pre- and post-ISP.