A digital speckle pattern interferometry system for automatic measurement of deformations of a diffuse object is presented by using phase-stepping and digital signal processing technique. Computer is utilized to take data and calculate phase without an intermediate recording step. Phase frings are produced instead of speckle correlation frings. Noise data points caused by randomness of the speckle are removed by digital signal processing. Two experimental results for the measurement of in-plane and off-plane deformations are presented.