In this case, {HEAD ~ a density} of information in a record on the file medium undergone the data compression is different from a density of {TAIL ~ information} in the original image 
In this case , { HEAD ~ a density } of information in a record on the file medium undergone the data compression is different from a density of { TAIL ~ information } in the original image
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH