Sushi Detector

For those confused, see Not Hotdog :)

@junji_watanabe Cool. For object detection model, perhaps all we need might be just sushi detection since basic structure is the same (rice and fish). Two stage classification may improve accuracy.

@hiromichinomata Actually, it can detect classes (salmon, kohada, chu-toro at this moment). and supports multi objects in a screen. But yeah, yours is simpler.