Coding Scheme for the Transmission of Satellite Imagery

Abstract

The coding and transmission of the massive datasets captured by Earth Observation (EO) satellites is a critical issue in current missions. The conventional approach is to use compression on board the satellite to reduce the size of the captured images. This strategy exploits spatial and/or spectral redundancy to achieve compression. Another type of redundancy found in such data is the temporal redundancy between images of the same area that are captured at different instants of time. This type of redundancy is commonly not exploited because the required data and computing power are not available on board the satellite. This paper introduces a coding scheme for EO satellites able to exploit this redundancy. Contrary to traditional approaches, the proposed scheme employs both the downlink and the uplink of the satellite. Its main insight is to compute and code the temporal redundancy on the ground and transmit it to the satellite via the uplink. The satellite then uses this information to compress more efficiently the captured image. Experimental results for Landsat 8 images indicate that the proposed dual link image coding scheme can achieve higher coding performance than traditional systems for both lossless and lossy regimes.

Learned Representation of Satellite Image Series for Data Compression

“…Preliminary studies on using the prior knowledge to improve the compression efficiency mainly focus on using images as references. In this work, the reference image can be an original historical image [32,33] or a synthesized image [24,26,34]. In our previous works [2], we used the current Google Map image as the historical reference.…”

Dual Link Image Coding for Earth Observation Satellites

“…When lossless coding is employed, the coding system must employ reversible transformations to allow the perfect recovery of the data. The preliminary study carried out in [9] indicates that the use of a dual link image coding scheme may increase the compression efficiency of the coding system. Fig.…”

“…Fig. 3 reports some of the results achieved in [9]. Lossless coding performance is appraised in Fig.…”

“…The proposed coding scheme employs both the downlink and the uplink, so we refer to it as dual link image coding. This research is built upon our previous work [9]. That work provides a proof of concept and demonstrates that the proposed method is feasible, but it employs only simple test images, does not propose a practical implementation, and does not consider synchronization aspects that may significantly affect performance.…”

“…The rest of the paper is organized as follows. Section II formulates the problem and reviews our previous work [9]. Section III introduces a practical image codec that utilizes the dual link image coding scheme.…”