Extended Data Fig. 1: Visualization of color distribution among the three cohorts.
From: Deep learning-enabled assessment of cardiac allograft rejection from endomyocardial biopsies
a. Polar scatter plot depicts the differences in the train (US) and test (US, Turkish, Swiss) cohorts, each acquired with different scanners and staining protocols. The angle represents the color (i.e. hue) and the polar axis corresponds to the saturation. Each point represents average hue and saturation of an image patch selected from each cohort. To construct the figure, 100 WSIs were randomly selected from each cohort. For each selected slide, 4 patches of size 1024×1024 at ×10 magnification were randomly selected from the segmented tissue regions. A hue–saturation–density color transform is taken to correct for the logarithmic relationship between light intensity and stain amount. The Swiss cohort demonstrates a large variation in both hue and saturation whereas the US and Turkish cohorts have a relatively uniform saturation but variable hue. Examples of patches with diverse hue and saturation from each cohort are shown in subplots b. and c.
