Phos is a dataset forevaluating illumination invariance: 15 scenes, 14 types of illumination (with shadows) + Ground Truth. It is a color image database of 15 scenes captured under different illumination conditions. More particularly, every scene of the database contains 15 different images: 9 images captured under various strengths of uniform illumination, and 6 images under different degrees of non-uniform illumination. The images contain objects of different shape, color and texture and can be used for illumination invariant feature detection and selection.Related publications:V. Vonikakis, D. Chrysostomou, R. Kouskouridas and A. Gasteratos, "A biologically inspired scale-space for illumination invariant feature selection" Measurement Science and Technology, vol. 24, no. 7, p. 074024 (13pp), 2013.V. Vonikakis, D. Chrysostomou, R. Kouskouridas and A. Gasteratos, "Improving the Robustness in Feature Detection by Local Contrast Enhancement", in Proceedings of the IEEE International Conference on Imaging Systems and Techniques (IST '12), pp. 158 - 163, Manchester, United Kingdom, 16-17 July 2012.