Saliency-driven rate-distortion optimization for 360-degree image coding

Chiang, Jui-Chiu; Yang, Chengyu; Dedhia, Bhishma; Char, Yi-Fan

doi:10.1007/s11042-020-10050-0

Cited by 3 publications

(1 citation statement)

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“…Based on the spatial-temporal joint saliency feature, the range of the quantization parameter was dynamically adjusted. In [ 15 ], Chiang et al proposed a saliency prediction model based on the stereographic projection method for 360-degree images. According to the saliency map, this model optimized the global rate-distortion to improve the image quality of Region-of-Interest (ROI) while reducing the overall bitrate.…”

Section: Introductionmentioning

confidence: 99%

Visual saliency guided perceptual adaptive quantization based on HEVC intra-coding for planetary images

2022

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Due to the limited storage space of spacecraft and downlink bandwidth in the data delivery during planetary exploration, an efficient way for image compression onboard is essential to reduce the volume of acquired data. Applicable for planetary images, this study proposes a perceptual adaptive quantization technique based on Convolutional Neural Network (CNN) and High Efficiency Video Coding (HEVC). This technique is used for bitrate reduction while maintaining the subjective visual quality. The proposed algorithm adaptively determines the Coding Tree Unit (CTU) level Quantization Parameter (QP) values in HEVC intra-coding using the high-level features extracted by CNN. A modified model based on the residual network is exploited to extract the saliency map for a given image automatically. Furthermore, based on the saliency map, a CTU level QP adjustment technique combining global saliency contrast and local saliency perception is exploited to realize a flexible and adaptive bit allocation. Several quantitative performance metrics that efficiently correlate with human perception are used for evaluating image quality. The experimental results reveal that the proposed algorithm achieves better visual quality along with a maximum of 7.17% reduction in the bitrate as compared to the standard HEVC coding.

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Section: Introductionmentioning

confidence: 99%