an image data obtaining unit that obtains image data including {HEAD ~ pixel data} corresponding to {TAIL ~ a plurality} of pixels forming the image 
corresponding to
an image data obtaining unit that obtains image data including { HEAD ~ pixel data } corresponding to { TAIL ~ a plurality } of pixels forming the image
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH