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Abstract The digital features of localized deformation of limestone are analyzed by using video images of uniaxial compression test. The original videos were record during the laboratory uniaxial compression test. The video images at loading stage were obtained by using load-time relation curves and converted into the video formats that can be recognized easily by computer. A particle image velocimetry(PIV) technique was used to compute the displacements of surface of limestone specimen in any time and in any location. The change history of tip displacement of the existing fissure was investigated；the processes of initiation and propagation of new fissures were also analyzed. The textural parameters of a single frame were selected as the digital features reflecting the deformation status of limestone. The change processes of these parameters with time were further investigated based on the grayscale histogram and grayscale co-occurrence matrix from video images. The results show that the phenomena of localized deformations of existing and new fissures are much obvious；the dividing point between stable and rapid deformation stages may be used to determinate the start point and to establish the initiate conditions for localized deformations；the textural parameters can reasonably reflect the change in the deformation status of the limestone under different loading stages and may be used to predict the initial time of localized deformations. Due to the reflection of image features on deformation/failure process of intact rocks or rock masses，the methods presented herein may provide a new research way of meso-scale mechanisms of the localized deformation and geological hazards in rock areas.
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Received: 14 May 2010
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2010, Vol. 29 
