A sinusoidal test pattern of modulation is imaged incoherently through a system whose…
PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Fourier optics and image formation · Fourier optics and image formation
What an Instrument Can See, Ch The transfer function of an imaging system
Problem
A sinusoidal test pattern of modulation m=0.80 is imaged incoherently through a system whose OTF has the value H=0.12 at the pattern's spatial frequency. The several pixels spanning one period of the pattern receive N=5000 photons in total over the exposure.
((a)) Compute the signal-to-noise ratio of the detected fringe at this spatial frequency, using the shot-noise result SNR=mHN/2.
((b)) State whether this spatial frequency is usably resolved, taking SNR≈3 as the practical threshold below which contrast is lost in the noise.