2D Gaussian structures injected on top of an fBm image with β = 2.4. The Gaussian functions all have an aspect ratio f = 0.2, a column density contrast between the peak of the 2D Gaussian and the mean value of the fBm, δ_c = 3, and a value of σ₁ that is varied between 150 and 16.67 pixels. Bottom-right figure: corresponding Δ-variance functions calculated for each case, and these are compared to the Δ-variance function calculated for the underlying fBm image.