We propose the first general framework to automatically correct different types of geometric distortion in a single input image. Our proposed method employs convolutional neural networks (CNNs) trained by using a large synthetic distortion dataset to predict the displacement field between distorted images and corrected images. A model fitting method uses the CNN output to estimate the distortion parameters, achieving a more accurate prediction. The final corrected image is generated based on the predicted flow using an efficient, high-quality resampling method. Experimental results demonstrate that our algorithm outperforms traditional correction methods, and allows for interesting applications such as distortion transfer, distortion exaggeration, and co-occurring distortion correction.
Multi-model distortion estimationThe GeoNetS network is only able to capture a specific distortion type with a distortion model at a time. For a new type, the entire network has to be retrained. Furthermore, the distortion type and model can be unknown in some cases. In view of these limitations, we designed a second network for multi-model distortion estimation. However, since the distortion model and the parameters ρ β can vary drastically across types, it is impossible to train a multimodel network with the model constraints. We train a network to regress the distortion flow without model constraints and at the same time classify the distortion type. The network is illustrated in Figure 3. The multi-model network N parameterized by θ is jointly trained for two tasks. The first task estimates the distortion flow, learning the mapping from the image domain I to the flow domain F. The second task classifies the distortion type, learning the mapping from image domain I to type domain T .Architecture The entire network adopts an encoderdecoder structure, which includes an encoder part, a decoder part, and a classification part. The input image is fed