Real-time speckle correlation by holographic matched filtering for measurement of microstructure changes and motion...

A real-time optical-correlation system employing a holographic matched filter is introduced for the measurement of microstructure changes in rough surfaces that additionally may execute a translatory motion. Object motion is measured by evaluating the correlation peak position. Changes in the surface structure of the object area under test are determined from the correlation peak intensity after the original object position has been restored. A photothermoplastic material in the holographic filter recording permits fast response of the system. The performance of the apparatus is demonstrated, and its application to the study of biological specimens is discussed.