Definition of parameters τ, ξ for m-ring model, along with respective marginalized uncertainties using Fisher information analysis. Left: A visualization of a stretched m-ring model with parameters τ=0.1, ξ=45^°, a brightness asymmetry of 0.23, and a diameter of d=46 μas, blurred with a Gaussian kernel with a full width at half maximum of 10 μas. The brightness position angle, η=45^°, is aligned with ξ. Right: Maps of marginalized uncertainties in the parameters τ (top row) and ξ (bottom row) for m-ring models with various values of τ and ξ, derived using Fisher information analysis on M87^* band 4 data.