Speckle shear interferometry, or shearography, has been more and more frequently used in the aerospace and oil and gas industry for in-field nondestructive inspections of flaws in composite materials. Nowadays new applications have emerged demanding the ability to operate in harsher environments, requiring more robust systems to meet this type of application. A recent modified shearography device allows multiple and simultaneous measurements with different shearing directions on a single grabbed image. This work proposes a robust integration algorithm by error minimization to obtain full-field displacement measurement. Simulated images are used to validate the effectiveness of the integration algorithm. Further, experiments are performed on a clamped circular plate with uniform loading. The proposed algorithm leads to a more accurate estimate of defect size measurement in composite materials.