In the training set annotations file (training.csv), it seems that the x1,y1, x2, y2 columns specify the upleft point and the downright point of the location of a fish in an image.
But in the 215th row of training.csv, I saw x1= 259, y1=620, x2=432,y2= 621, so the width of fish is just one pixel if use y2 minus y1. I visualize the rectangle on the image and found it was not true. This phenomenon is not unique to the 215th row.
Could someone explain how to interpret x1, y1, x2, y2?