Hilbert Scan

The Hilbert curve has been applied to image processing as a scanning technique (Hilbert scan). 
This scan is guided by the Hilbert space filling curve. 

see also:
  http://en.wikipedia.org/wiki/Hilbert_curve
  http://rest-term.com/archives/1204/

スキャンオーダーにヒルベルト曲線を利用
8次で空間充填、ヒルベルトスキャン