发明名称 |
Method and apparatus for viewing a shearographic image |
摘要 |
A shearogram representing an object and including a fringe pattern arising from a change in local surface strain brought about by an applied stress during the making of the shearogram is reconstructed by a special viewer. The viewer holds the shearogram transparency adjacent to a focusing lens having an optical axis, and projects off-axis white light through the lens and transparency to a focal plane where the resulting diffraction pattern is viewed directly on a screen or by a video camera and display monitor. By projecting the light from different positions around the axis a first position can be found which tunes the diffraction efficiency to an optimum for the best view of fringe patterns and a second position can be found which eliminates the fringe patterns and shows only a photographic image of the object. The light source is a rotatable disk with two apertures containing light diffusing elements which are illuminated by a lamp. The disk is rotated to change the projection angle.
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申请公布号 |
US5414512(A) |
申请公布日期 |
1995.05.09 |
申请号 |
US19930029163 |
申请日期 |
1993.03.10 |
申请人 |
GRANT ENGINEERING, INC. |
发明人 |
GRANT, RALPH M.;WRIGHT, FORREST |
分类号 |
G01B9/025;G01B11/16;(IPC1-7):G01B9/02 |
主分类号 |
G01B9/025 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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