Figure 1. Image Preprocessing: From original image to the one used for classification.

The original image is submitted to an ImageJ script (S1 Fig. for the code) which allows to automatically crop the zebrafish embryo into a square as far as possible. The embryo will be surrounded by a rectangle if it is placed near the sides of the original image. We use a connected-component labeling approach combined with different morphological transformations and binarizations, in order to localize the embryo.