Abstract

Electronic speckle photography offers a simple and fast technique for measuring in-plane displacement fields in solid and fluid mechanics. Errors from undersampling, illumination divergence, and displacement magnitude have been analyzed and measured. The nature of the systematic error is such that a drift toward the closest integral pixel value is introduced. Because of the finite extent of the sensor area, considerable undersampling is tolerable before systematic errors occur. The random errors are mainly dependent on the effective f-number of the imaging system and speckle decorrelation introduced by object displacement. When sampling at a rate of ~70% of the Nyquist frequency, we avoided systematic errors and minimized random errors.

© 1994 Optical Society of America

Electronic speckle photography: increased accuracy by nonintegral pixel shifting

M. Sjödahl
Appl. Opt. 33(28) 6667-6673 (1994)

Electronic speckle photography: analysis of an algorithm giving the displacement with subpixel accuracy

M. Sjödahl and L. R. Benckert
Appl. Opt. 32(13) 2278-2284 (1993)

Accuracy in electronic speckle photography

M. Sjödahl
Appl. Opt. 36(13) 2875-2885 (1997)

Electronic speckle photography: measurement of in-plane strain fields through the use of defocused laser speckle

M. Sjödahl
Appl. Opt. 34(25) 5799-5808 (1995)

Measurement of shape by using projected random patterns and temporal digital speckle photography

Mikael Sjödahl and Per Synnergren
Appl. Opt. 38(10) 1990-1997 (1999)