Glad you figured it out: To clarify further: for a 'Good' field we're pretty sure the center pixel is the field, for a medium one the center pixel is the best guess for the field and for a low quality one we have no clue :)

thanks for reply

in data explanation there are note:

The imagery is all presented at 10m resolution, and the image is 41px a side. The center (im[20, 20]) is the field location.

but I found that some images have 40 or 42 pixels a side