Patch-based image colorization

Image colorization consists in adding colors to grayscale images. Two approaches are mainly used: the first one consists in using manually pre-defined color inputs while the second consider an entire colored image as color example to transfer. The work presented here is in the second category. Indeed, we propose a simple patch-based image colorization based on an input image as a color example. First, we introduce a general colorization model in which many methods of literature can be casted within this framework. Second, we describe our method which is based on patch descriptors of luminance features and a color prediction model with a general distance selection strategy. We also propose to perform a Total Variation (TV) regularization on the colorized image to ensure the spatial color coherency of the final result. Finally, experiments show the potentiality of our proposition in order to automatically colorize grayscale images. Comparisons with methods from the literature are also provided.