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arXiv 2203.01941cs.CVcs.LG
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基于残差Quantization的自回归图像生成

Autoregressive Image Generation using Residual Quantization

POSTECH(浦项科技大学);Kakao Brain

Doyup Lee, Chiheon Kim, Saehoon Kim, Minsu Cho, Wook-Shin Han

摘要:

对于高分辨率图像的自回归(AR)建模,矢量量化(VQ)将图像表示为离散代码序列。短序列长度对于AR模型降低其计算成本以考虑代码的长程相互作用是重要的。然而,我们假设,以前的矢量量化不能缩短代码序列,并产生高保真度的图像在率失真权衡。在这项研究中,我们提出了两个阶段的框架,其中包括残余量化VAE(RQ VAE)和RQ变压器,有效地产生高分辨率的图像。给定一个固定的码书大小,RQ-VAE可以精确地近似图像的特征图,并表示为离散码的堆叠图的图像。然后,RQ-Transformer通过预测下一个代码堆栈来学习预测下一个位置的量化特征向量。由于RQ-VAE的精确近似,我们可以将256 $\times$ 256图像表示为8 $\times$ 8分辨率的特征图,并且RQ-Transformer可以有效地降低计算成本。因此,我们的框架优于现有的AR模型在各种基准的无条件和有条件的图像生成。我们的方法还具有比以前的AR模型更快的采样速度,以生成高质量的图像。

英文摘要:

For autoregressive (AR) modeling of high-resolution images, vector quantization (VQ) represents an image as a sequence of discrete codes. A short sequence length is important for an AR model to reduce its computational costs to consider long-range interactions of codes. However, we postulate that previous VQ cannot shorten the code sequence and generate high-fidelity images together in terms of the rate-distortion trade-off. In this study, we propose the two-stage framework, which consists of Residual-Quantized VAE (RQ-VAE) and RQ-Transformer, to effectively generate high-resolution images. Given a fixed codebook size, RQ-VAE can precisely approximate a feature map of an image and represent the image as a stacked map of discrete codes. Then, RQ-Transformer learns to predict the quantized feature vector at the next position by predicting the next stack of codes. Thanks to the precise approximation of RQ-VAE, we can represent a 256$\times$256 image as 8$\times$8 resolution of the feature map, and RQ-Transformer can efficiently reduce the computational costs. Consequently, our framework outperforms the existing AR models on various benchmarks of unconditional and conditional image generation. Our approach also has a significantly faster sampling speed than previous AR models to generate high-quality images.

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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