The linearmosaic tool (lm) provides a toolkit for stitching images in a weighted fashion. The default linear mosaic equation is defined by Equation (6) in Cornwell, Holdaway et al (Astronomy and Astrophysics, Vol. 271, p. 697 (1993)).

$I^{lm}(\theta)={{\sum_p A_p(\theta)(I_p(\theta)A_p(\theta))w_p}\over{\sum_p A_p^2(\theta)w_p}}$

where $A_p(\theta)$ is the primary beam (PB) of a given pointing $p$, $w_p$ is a sensitivity weight and the image of that pointing is $I_p(\theta)$; the linear mosaic being $I^{lm}(\theta)$