Multiscale decomposition using the starlet transform. Left panel: original image, similar to source galaxies in Sects. 5 and 6. Middle panels: scales of the starlet decomposition using 6 spatial scales, and normalised (max = 1) to enhance the contrast. In such a decomposition, a feature of a given scale is “brighter” in the corresponding image in the decomposition. Hence, keeping only highest pixels in each starlet scale filters out any insignificant signal over a large spectrum of spatial extents. All scale images have the same dimensions as the input image. Right panel: reconstructed image from all the decomposition scales, through co-addition of all decomposition scales. (https://github.com/aymgal/SLITronomy-papers/blob/master/paper_I/visualize_starlet_transform.ipynb.)