Blind Quality Assessment for 3D-synthesized Images by Measuring Geometric Distortions and Image Complexity

摘要

Free viewpoint video (FVV), owing to its comprehensive applications in immersive entertainment, remote surveillance and distanced education, has received extensive attention and been regarded as a new important direction of video technology development. Depth image-based rendering (DIBR) technologies are employed to synthesize FVV images in the "blind" environment. Therefore, a real-time reliable blind quality assessment metric is urgently required. However, existing stste-of-art quality assessment methods are limited to estimate geometric distortions generated by DIBR. In this research, a novel blind quality metric, measuring Geometric Distortions and Image Complexity (GDIC), is proposed for DIBR-synthesized images. Firstly, a DIBR-synthesized image is decomposed into wavelet subbands by using discrete wavelet transform. Then, we adopt canny operator to capture the edge of wavelet subbands and compute the edge similarity between low-frequency subband and highfrequency subbands. The edge similarity is used to quantify geometric distortions in DIBR-synthesized images. Secondly, a hybrid filter combining the autoregressive and bilateral filter is adopted to compute image complexity. Finally, the overall quality score is calculated by normalizing geometric distortions via image complexity. Experiments show that our proposed GDIC is superior to prevailing image quality assessment metrics, which were intended for natural and DIBR-synthesized images.