Fig. 1: Given the original image $mathbf{x}$, we would like to generate a compressed image $hat{mathbf{x}}$ such that the user’s action $mathbf{a}$ upon seeing the compressed image is similar to what it would have been had the user seen the original image instead. In a 2D top-down car racing video game with an extremely high compression rate (50%), our compression model learns to preserve bends and discard the road farther ahead.
Imagine remotely operating a Mars rover from a desk on Earth. The low-bandwidth network connection can make it challenging for the teleoperation system to provide the user with high-dimensional observations like images. One approach to this problem is to use data compression to minimize the number of bits that need to be communicated over the network: for example, the rover can compress the pictures it takes on Mars before sending them to the human operator on Earth. Standard lossy image compression algorithms would attempt to preserve the image’s appearance. However, at low bitrates, this approach can waste precious bits on information that the user does not actually need in order to perform their current task. For example, when deciding where to steer and how much to accelerate, the user probably only pays attention to a small subset of visual features, such as obstacles and landmarks. Our insight is that we should focus on preserving those features that affect user behavior, instead of features that only affect visual appearance (e.g., the color of the sky). In this post, we outline a pragmatic compression algorithm called PICO that achieves lower bitrates by intentionally allowing reconstructed images to deviate drastically from the visual appearance of their originals, and instead optimizing reconstructions for the downstream tasks that the user wants to perform with them (see Fig. 1).
Pragmatic Compression
The straightforward approach to optimizing reconstructions for a specific task would be to train the compression model
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