Abstract
Principles of coherent and non-coherent double exposure Speckle photography are presented with evaluation of shift changes in continuous and discrete areas. The aim of this work is to demonstrate that this computer method can be also employed in medical research. It may be transformed for the study of small deformations of the specimens of lumbar spines during applications of different physical strains.•Incoherent computer speckle interferometry was used to visualize small changes in the assessment of lumbar spine surgical fixation.•Vertebral movement is contactless monitored by two cheap CCD cameras and evaluated using computer technology.•The results obtained were verified on a cadaveric sample of human spine.