a) Our CNN (b) Ground truth Figure 1: Our convolutional neural network performs the entire processing involved in an image signal processing (ISP) pipeline including denoising, white balancing, exposure correction, demosaicing, color transform, and gamma encoding. Results for our method and ground truth image are shown: (a) our CNN-based ISP and (b) ground truth image. In each image, a zoomed in view of the white rectangular region is displayed in the top left hand corner (inside the black rectangle). It can be seen that the CNN output looks almost identical to the ground truth image.
ABSTRACTA conventional camera performs various signal processing steps sequentially to reconstruct an image from a raw Bayer image. When performing these processing in multiple stages the residual error from each stage accumulates in the image and degrades the quality of the final reconstructed image. In this paper, we present a fully convolutional neural network (CNN) to perform defect pixel correction, denoising, white balancing, exposure correction, demosaicing, color transform, and gamma encoding. To our knowledge, this is the first CNN trained end-to-end to perform the entire image signal processing pipeline in a camera. The neural network was trained using a large image database of raw Bayer images. Through extensive experiments, we show that the proposed CNN based image signal processing system performs better than the conventional signal processing pipelines that perform the processing sequentially.