The difference in light intensity in an object or image; defined as (Imax – Imin)/(Imax + Imin), where Imax and Imin are the maximum and minimum intensities.
SPHERICAL VS. ASPHERIC LENSES
HOW THEY’RE USED IN IMAGING APPLICATIONS
Optical Lenses are often categorized by their shape. Two common surface shapes are spherical and aspherical. Each offers unique characteristics that make it suitable for different use cases.