Deep Near Infrared Colorization with Semantic Segmentation and Transfer Learning

Although near infrared (NIR) images contain no color, they have abundant and clear textures. In this paper, we propose deep NIR colorization with semantic segmentation and transfer learning. NIR images are capable of capturing invisible spectrum (700-1000 nm) that is quite different from visible spectrum images. We employ convolutional layers to build relationship between single NIR images and three-channel color images, instead of mapping to Lab or YCbCr color space. Moreover, we use semantic segmentation as global prior information to refine colorization of smooth regions for objects. We use color divergence loss to further optimize NIR colorization results with good structures and edges. Since the training dataset is not enough to capture rich color information, we adopt transfer learning to get color and semantic information. Experimental results verify that the proposed method produces a natural color image from single NIR image and outperforms state-of-the-art methods in terms of peak signal-to-noise ratio (PSNR) and structural similarity (SSIM).