Measurement error caused by speckle noise in heterodyne and quasi-heterodyne holographic interferometry.

In heterodyne and quasi-heterodyne holographic interferometry, the measuring accuracy is limited by speckle noise. It is important to know the relation between measurement accuracy and speckle noise in both theory and application. This problem has been discussed in the past under the assumption that the speckle noise produces only a small measuring error. However, this assumption is not reasonable in practice. The effect of speckle noise on the measurement accuracy is analyzed by the use of a general statistical method. The results obtained reveal the general relation between the measuring accuracy and system parameters, and thus constitute important guidelines to the application of these techniques.