Input dataset for the GTN tutorial titled 'Voronoi segmentation'. The dataset contains two images: Grayscale image (L mode): A grayscale version of the original three-channel image, obtained using pillow python package Seed image: generated through the following preprocessing steps: Increasing the dynamic range Smoothing Histogram equalization Thresholding These images are processed versions of the original sky image part of Legacy Survey DR 10 that can be directly downloaded using this link. This image is taken around the region defined by R.A.=53.16216667 deg. and Dec.=-27.79149167 deg. with a pixel scale of 0.262 arcsec. The original image is published under Creative Commons Attribution 4.0 International License licence by Legacy Surveys / D. Lang (Perimeter Institute). Acknowledgments for all Data from the Legacy Surveys. An overview of the Legacy Surveys is available in Dey et al. (2019).