Perceived depth quality - preserving visual comfort improvement method for stereoscopic 3D images

Abstract The improvement of visual comfort (VC) of stereoscopic three-dimensional (S3D) images is often accompanied with a decline in the perceived depth (PD) quality which involves three senses: presence, power, and realism. To address this problem, this paper proposes a novel PD quality - preserving VC improvement method for S3D images. First, an overall visual experience index termed 3D visual satisfaction which accounts for both VC and PD quality is defined. Then, a new viewing distance nonlinear shifting (VDNS) scheme is developed to improve the VC of S3D images and VDNS-based rendering method is proposed to generate new S3D images. A subjective assessment experiment is conducted on S3D image database, consisting of discomfort S3D images and their VDNS-based rendering images to obtain the corresponding ground truth 3D visual satisfaction scores. Based on the labeled dataset, an objective 3D visual satisfaction assessment model is presented, which integrates VC and PD quality and denotes as VCPD model. Using the VCPD model as guidance, VDNS is used to improve the VC and 3D visual satisfaction of S3D images in a stepwise manner without introducing geometric proportional distortion. As a result, the adjusted S3D image can provide better 3D visual satisfaction to viewers, i.e., improving the VC while preserving the PD quality. Experimental results show that the proposed method can achieve better comprehensive performance in improving both of VC and PD quality than other relevant methods as it can provide the optimal 3D visual satisfaction.