| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an electron beam device capable of recording an image at the same sample position and in a focused state over a long time in an unattended environment. <P>SOLUTION: Immediately after a video tape recording (VTR) start, a drift detection part 16 stores a sample image photographed by a TV camera 11 in its internal memory M<SB>A</SB>as an initial reference image. During the video tape recording, the detection part 16 introduces the sample image being currently photographed by the TV camera 11 into its internal memory M<SB>B</SB>as a present image at every time interval T<SB>1</SB>to correct a drift by detecting the displacement of the present image from the reference image. A focus deviation detection part 17 performs focusing at every time interval t<SB>2</SB>during the video tape recording. During the video tape recording, the detection part 16 updates the reference image in the memory M<SB>A</SB>by overwriting it with the sample image currently photographed by the TV camera 11 at every time interval t<SB>3</SB>. <P>COPYRIGHT: (C)2004,JPO</p> |
