Februray 9th Friday (一月 九日 金曜日)

  How to smooth a bitmap file?  We can search out the adjacent eights points of a point, and work out the
averge value of these nine points.  It is essential to change the value of a point and make its value approximate
its neighbors.  In this way, edges in a picture can be smoothed.

  On the contrary, what if we make a point value set out of its neighbors?  It just is alike that a white
point at a black broad.  It that way, we can sharpen a picture.  Sharpening a picture we usually find some
noise points or lines in a picture at once.

  A pixel or a point on the screen usually maps a block in a printer or other output device.  The block is
called as "pixel".  A "pixel" includes many a point.  By the way, a "pixel" is so tiny that we usually consider
it as a point.  A "pixel"'s gray degree is represented by number of its including black points.  In other words,
the gray degree of a "pixel" varies from the number of its black points.