FOURIER SERIES AND LAPLACIAN NOISE-BASED QUANTIZATION ERROR COMPENSATION FOR END-TO-END LEARNING-BASED IMAGE COMPRESSION

Quantization is a core operation in lossy image compression. In the end-to-end learning-based image compression framework, quantization is conducted by a rounding operation during test, while it is replaced by additive uniform noise during training, leading to a mismatched problem between train and test. To address this problem, we propose a quantization error compensation method for the end-to-end learning-based image compression framework. The method uses Fourier series to approximate the periodic changes of the quantization error, and adds Laplacian noise to the quantized latent during test. The proposed method can be flexibly combined with different end-to-end learning-based image compression methods. Experimental results show that higher coding efficiency can be achieved by adding the proposed method with the state-of-the-art methods.