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arXiv 2209.03353eess.IVcs.LG
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基于广义倍频程卷积和互分辨率参数估计的学习图像压缩

Learned Image Compression with Generalized Octave Convolution and Cross-Resolution Parameter Estimation

Xi'an Jiaotong University(西安交通大学)

Haisheng Fu, Feng Liang

摘要:

上下文自适应熵模型的应用显着提高率失真(R-D)性能,其中超先验和自回归模型联合使用,以有效地捕获潜在表示的空间冗余。然而,潜在的表征仍然包含一些空间相关性。另外,这些基于上下文自适应熵模型的方法不能在解码过程中通过并行计算设备(例如FPGA或GPU)来加速。为了减轻这些限制,我们提出了一个学习的多分辨率图像压缩框架,它利用最近开发的倍频程卷积分解的潜在表示为高分辨率(HR)和低分辨率(LR)的部分,类似于小波变换,这进一步提高了R-D性能。为了加快解码速度,我们的方案不使用上下文自适应熵模型。相反,我们利用一个额外的超层,包括超编码器和超解码器,以进一步消除潜在表示的空间冗余。此外,交叉分辨率参数估计(CRPE)被引入到所提出的框架,以加强信息流,进一步提高率失真性能。提出了一个额外的信息保真度损失的总损失函数,以调整LR部分的最终比特流的贡献。实验结果表明,与现有的图像压缩方法相比,该方法的解码时间分别减少了约73.35%和93.44%,并且在较宽的比特率范围内,在PSNR和MS-SSIM指标上,R-D性能仍优于H. 266/VVC(4:2:0)和一些基于学习的方法。

英文摘要:

The application of the context-adaptive entropy model significantly improves the rate-distortion (R-D) performance, in which hyperpriors and autoregressive models are jointly utilized to effectively capture the spatial redundancy of the latent representations. However, the latent representations still contain some spatial correlations. In addition, these methods based on the context-adaptive entropy model cannot be accelerated in the decoding process by parallel computing devices, e.g. FPGA or GPU. To alleviate these limitations, we propose a learned multi-resolution image compression framework, which exploits the recently developed octave convolutions to factorize the latent representations into the high-resolution (HR) and low-resolution (LR) parts, similar to wavelet transform, which further improves the R-D performance. To speed up the decoding, our scheme does not use context-adaptive entropy model. Instead, we exploit an additional hyper layer including hyper encoder and hyper decoder to further remove the spatial redundancy of the latent representation. Moreover, the cross-resolution parameter estimation (CRPE) is introduced into the proposed framework to enhance the flow of information and further improve the rate-distortion performance. An additional information-fidelity loss is proposed to the total loss function to adjust the contribution of the LR part to the final bit stream. Experimental results show that our method separately reduces the decoding time by approximately 73.35 % and 93.44 % compared with that of state-of-the-art learned image compression methods, and the R-D performance is still better than H.266/VVC(4:2:0) and some learning-based methods on both PSNR and MS-SSIM metrics across a wide bit rates.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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