Subset noise bias compensation for tone-mapping and up-scaling of JPEG images

The super resolution technique plays an important role in displaying a conventional low resolution (LR) image on a recently developed high resolution (HR) display. In its process, some of enhancement techniques such as de-noising, de-blurring and tone-mapping are combined to increase visual quality. This paper introduces a subset noise bias compensation (NBC) to an LR-to-HR up-conversion process which is composed of tone-mapping and up-scaling. In our system, 1) an LR image is encoded and decoded with JPEG, 2) pixels in the decoded noisy image are tone-mapped, 3) observed pixel values are classifies into subsets and the bias of each subset is compensated with an optimally designed compensation value, and 4) the images are up-scaled with a state-of-the-art super-resolution technique. Improvement by the proposed method is confirmed with PSNR and SSIM evaluation measures, respectively.