Michelson contrast

The Michelson contrast is commonly used for patterns where both bright and dark features are equivalent and take up similar fractions of the area. The Michelson contrast is defined as



\frac{I_\mathrm{max}-I_\mathrm{min}}{I_\mathrm{max}+I_\mathrm{min}}, $$

with $$ I_\mathrm{max} $$ and $$ I_\mathrm{min} $$ representing the highest and lowest luminance. The denominator represents twice the average of the luminance.