Fig. 1
a The initial contact map is repeatedly convolved with increasing 2D Gaussians to produce a scale-space representation of the image (shown on the left). Pairwise adjacent Gaussian images are subtracted to produce the difference-of-Gaussian (DoG) images (on the right). b Maxima of the difference-of-Gaussian images are detected by comparing each pixel to its 3 ×3×3 neighborhood in (x,y,σ) space. Note that DoG is a local maximum at (x,y) location at scales si and si+1 but not at scale si−1, therefore passing the first filtering step criteria. c Chromatin loops can be caused by the contact between pairs of DNA segments at different scales