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