title: matlab image uint8 Array, finding top most left/top/bottom/right pixel location
body: <p>How is the image data saved with an uint8 array? Say that I have an obscure circular image, instead of a rectangular, so there is no pixel data beyond the circle. How do I go about the top most pixel location? The bottom most? Etc... And this image does not have to be a circle, it could be something obscure and non-geometric.</p>