RSDI – PCA S/N density curve after having used the whole data set of SHARDDS per object; the Sthгel variable and the image similarity methods; and comparing it with the S/N values provided by the random selection (in green). The black curve corresponds to the full-frame method, the blue one to the optimization-zone method, and the green one to the random distribution; the dotted line corresponds to the maximum values per curve. The best performance is provided by the correlation with a median of 6.2 and a maximum S/N value of 9.1.