Example Av maps and N-PDFs. Left: Av maps of Ophiuchus and Cepheus I (Zucker et al. 2021). The orange contours trace A_V = 8 mag, while the blue contours trace N_threshold. The young embedded protostars (Class 0, I, and Flatspectrum sources) are presented as magenta crosses (Dunham et al. 2015). Ophiuchus is a good representative of nearby star-forming clouds, while Cepheus I presents an extreme case with very low SFR. Right: N-PDFs of the Ophiuchus and Cepheus I generated based on Herschel PACS and SPIRE images (black). The fittings of a lognormal component and a power-law tail are shown as an orange dashed line and a blue line. We plot the N-PDF of the pixels within the A_V = 8 mag contour in this panel, which is shown in the gray-blue area.