Shadow-Free TILT for facade rectification

In this paper, we propose a shadow-free TILT method to rectify facade images corrupted by shadows. The proposed method is deduced from the original TILT, and improve it by introducing a multiplicative shadow factor. That is, in our method, the constraint is represented that the rectified image equals to the low-rank image multiplied by the shadow image, yet with the additive noise corruption. Moreover, the objective function is improved by incorporating the smooth shadow model. Experimental results on both synthetic and real images demonstrate that our method provides more accurate and stable rectification results as compared with the original TILT, especially when shadows are strong in the input images.