Autoencoder

Image compression

Pattern recognition (psychology)

Codec

Quantization (signal processing)

Mathematics

JPEG 2000

Data compression

Algorithm

Image (mathematics)

Mathematical optimization

Artificial intelligence

Lossy compression

Computer science

Computer hardware

Data compression ratio

Computer vision

Artificial neural network

Rate–distortion theory

Lagrange multiplier

Image processing

In this paper, we propose a novel variable-rate learned image compression framework with a conditional autoencoder. Previous learning-based image compression methods mostly require training separate networks for different compression rates so they can yield compressed images of varying quality. In contrast, we train and deploy only one variable-rate image compression network implemented with a conditional autoencoder. We provide two rate control parameters, i.e., the Lagrange multiplier and the quantization bin size, which are given as conditioning variables to the network. Coarse rate adaptation to a target is performed by changing the Lagrange multiplier, while the rate can be further fine-tuned by adjusting the bin size used in quantizing the encoded representation. Our experimental results show that the proposed scheme provides a better rate-distortion trade-off than the traditional variable-rate image compression codecs such as JPEG2000 and BPG. Our model also shows comparable and sometimes better performance than the state-of-the-art learned image compression models that deploy multiple networks trained for varying rates.

Variable Rate Deep Image Compression With a Conditional Autoencoder