Processing times were measured on an iMac with a 3.6 GHz 10-Core Intel Core i9 processor with 64 GB of RAM and an AMD Radeon Pro 5500 XT 8 GB GPU. Tensorflow was configured to use the AMD GPU according to [40]. The GPU was used in U-Net training and segmentation steps. The dataset analyzed is from [10] and consists of 26 GB of raw image data (12 hours, 262 time frames, 2 imaging planes, 34 FOVs, and ~35 growth channels per FOV). Note that while the Otsu segmentation method is slightly faster than the U-Net, it also requires a background subtraction step, such that the total runtimes of the two methods are comparable.