From the threshold gap size of the Landolt C test symbol d (in m) and the distance between the test pattern and the camera D (in m) the smallest discernable detail ωc (in arcmin) is calculated as follows:
Le plus petit détail discernable ωc (arc-min) est calculé comme suit, à partir de la largeur seuil d (m) de la brisure de l &apos; anneau et de la distance entre le motif d &apos; essai et la caméra D (m):