Fine granularity access in interactive compression of 360-degree images based on rate-adaptive channel codes
This work addresses the need for efficient and interactive transmission of 360-degree images, which is incremental as it builds on existing compression methods with a novel adaptation.
The paper tackles the problem of interactive compression for 360-degree images by proposing a scheme that balances efficient compression with random access, using rate-adaptive channel codes to enable flexible data extraction based on user requests. Experimental results show it achieves a better transmission rate than state-of-the-art tile-based methods with a small storage cost and avoids staircase effects.
In this paper, we propose a new interactive compression scheme for omnidirectional images. This requires two characteristics: efficient compression of data, to lower the storage cost, and random access ability to extract part of the compressed stream requested by the user (for reducing the transmission rate). For efficient compression, data needs to be predicted by a series of references that have been pre-defined and compressed. This contrasts with the spirit of random accessibility. We propose a solution for this problem based on incremental codes implemented by rate-adaptive channel codes. This scheme encodes the image while adapting to any user request and leads to an efficient coding that is flexible in extracting data depending on the available information at the decoder. Therefore, only the information that is needed to be displayed at the user's side is transmitted during the user's request, as if the request was already known at the encoder. The experimental results demonstrate that our coder obtains a better transmission rate than the state-of-the-art tile-based methods at a small cost in storage. Moreover, the transmission rate grows gradually with the size of the request and avoids a staircase effect, which shows the perfect suitability of our coder for interactive transmission.