Straight Lines Have To Be Straight: Erratum

This is an erratum for the following article: F. Devernay et O. Faugeras, Straight Lines Have to Be Straight: Automatic Calibration and Removal of Distortion from Scenes of Structured Environments, Machine Vision and Applications, 1, 2001, pp. 14-24 (PDF).

Formula (9) should read (in maple code):
rd := (R+sqrt(Delta))**(1/3)-Q/((R+sqrt(Delta))**(1/3)):
and not
rd := (R+sqrt(Delta))**(1/3)+Q/((R+sqrt(Delta))**(1/3)):