Emmanuel Christophe

Google Inc. | Google · Engineering Department

The 2009–2010 Data Fusion Contest organized by the Data Fusion Technical Committee of the IEEE Geoscience and Remote Sensing Society was focused on the detection of flooded areas using multi-temporal and multi-modal images. Both high spatial resolution optical and synthetic aperture radar data were provided. The goal was not only to identify the be...

As the amount of data and the complexity of the processing rise, the demand for processing power in remote sensing applications is increasing. The processing speed is a critical aspect to enable a productive interaction between the human operator and the machine in order to achieve ever more complex tasks satisfactorily. Graphic processing units (G...

Lusi is a mud volcano in East Java, Indonesia, which started its eruption on 29th May 2006 and never stopped. To study this volcano, we used SAR interferometry with ALOS/Palsar satellite images from 2006 to 2010. By creation of a set of interferograms, and suppression of unwanted components, such as Earth curvature and elevation, we were able to co...

Hyperspectral data are a challenge for data compression. Several factors make the constraints particularly stringent and the challenge exciting. First is the size of the data: as a third dimension is added, the amount of data increases dramatically making the compression necessary at different steps of the processing chain. Also different propertie...

This paper discusses several ways in which a community of volunteers can be put together to generate good quality geographical information by the use of remote sensing image analysis tools. Three different scenarios are proposed and a system architecture, based on existing open source solutions, is suggested and discussed. The main objective of thi...

On September 30th, 2009, a major earthquake of magnitude 7.6 occurred near the west coast of Sumatra close to the city of Padang. On October 1st a significant aftershock (magnitude 6.6) occurred 270 km away. The casualties are estimated at 1200. This earthquake comes at a time when seismic activity in the region is particularly high. The purpose of...

Baseline calibration is needed in most of SAR interferometry processing. An iterative optimization of baseline with constrain of relative platform position is presented in this paper. The SAR passes which gives inaccurate platform position is successfully detected and calibrated using this algorithm. After processing, new estimated baseline improve...

Mangroves are an important part of the ecosystem in tropical region. Unfortunately, they are also under intense ecological pressure from fishing, tourism or logging. As they are often in not easily accessible places and scattered over large areas, satellite observation is an ideal solution to monitor the mangrove evolution over the past few years....

The 2008 Data Fusion Contest organized by the IEEE Geoscience and Remote Sensing Data Fusion Technical Committee deals with the classification of high-resolution hyperspectral data from an urban area. Unlike in the previous issues of the contest, the goal was not only to identify the best algorithm but also to provide a collaborative effort: The de...

Orfeo Toolbox, OTB, is a remote sensing image processing library developed by CNES, the French Space Agency. OTB is distributed as open source software and is therefore available for any remote sensing scientist or processing chain developer. This paper describes the main features of OTB, how it can be used and the expected evolutions in the coming...

Satellite observation is particularly enticing due to its large acquisition capabilities. However these large capabilities kindle new challenges for information analysis. Object counting is one of those. To help releasing constraints on the human operator, it is important to free him from repetitive tasks and focus his attention on the high level t...

High resolution remote sensing image segmentation is a great challenge in terms of potential applications, but also because of the difficulty of the task. Fully automatic algorithms are not able to extract all the desired features from complex images but visual image analysis is time consuming and tedious (therefore error prone). In this work we pr...

This paper presents the initial results of the algorithm performance contest that was organized as part of the 5th IAPR Workshop on Pattern Recognition in Remote Sensing (PRRS 2008). The focus of the 2008 contest was automatic building detection and digital surface model (DSM) extraction. A QuickBird data set with manual ground truth was used for b...

Hyperspectral images present some specific characteristics that should be used by an efficient compression system. In compression, wavelets have shown a good adaptability to a wide range of data, while being of reasonable complexity. Some wavelet-based compression algorithms have been successfully used for some hyperspectral space missions. This pa...

This paper deals with the optimization of a new technique of image compression. After the wavelet transform of an image, blocks of coefficients are further linearly decomposed using a basis selected in a dictionary. This dictionary is known by both the encoder and the decoder. This approach is a generalization of the bandelet transform. This paper...

End users of large volume image datasets are often interested only in certain features that can be identified as quickly as possible. For hyperspectral data, these features could reside only in certain ranges of spectral bands and certain spatial areas of the target. The same holds true for volume medical images for a certain volume region of the s...

Assessing the quality of a hyperspectral image is a difficult task. However, this assessment is required at different levels of the instrument design: evaluation of the signal to noise ratio necessary for a particular application, determining the acceptable level of losses from compression algorithms for example. It has been shown previously that a...

Future high resolution instruments planned by CNES for space remote sensing missions will lead to higher bit rates because of the increase in resolution, dynamic range and number of spectral channels for multispectral (up to 16 bands) and hyperspectral (hundreds of bands) imagery. Lossy data compression is then needed, with compression ratio goals...

Future high resolution instruments planned by CNES for space remote sensing missions will lead to higher bit rates because of the increase in resolution, dynamic range and number of spectral channels for multispectral (up to 16 bands) and hyperspectral (hundreds of bands) imagery. Lossy data compression is then needed, with compression ratio goals...

Zerotree based coders have shown a good ability to be successfully adapted to 3D image coding. This paper focuses on the adaptation of EZW for the compression of hyperspectral images with reduced complexity. The subordinate pass is removed so that the location of significant coefficients does not need to be kept in memory. To compensate the quality...

Zerotrees of wavelet coefficients have shown a good adaptability for the compression of three-dimensional images. EZW, the original algorithm using zerotree, shows good performance and was successfully adapted to 3D image compression. This paper focuses on the adaptation of EZW for the compression of hyperspectral images. The subordinate pass is su...

Automatic road extraction is a critical feature for an efficient use of remote sensing imagery in most contexts. This paper proposes a robust geometric method to provide a first step extraction level. These results can be used as an initialization for other algorithms or as a starting point for manual road extraction. Results of the extraction are...

With the increase of remote sensing images, fast access to some features of the image is becoming critical. This access could be some part of the spectrum, some area of the image, high spatial resolution. An adaptation of 3D-SPIHT image compression algorithm is presented to allow random access to some part of the image, whether spatial or spectral....

Hyperspectral sensors have been of a growing interest over the past few decades for Earth observation as well as deep space exploration. However, the amount of data provided by such sensors requires an efficient compression system which is yet to be defined. It is hoped that the particular statistical properties of such images can be used to obtain...

Hyperspectral data appear to be of a growing interest over the past few years. However, applications for hyperspectral data are still in their infancy as handling the significant size of the data presents a challenge for the user community. Efficient compression techniques are required, and lossy compression, specifically, will have a role to play,...

Hyperspectral data appears to be of a growing interest over the past few years. However, applications for hyperspectral data are still in their infancy. Handling the significant size of hyperspectral data presents a challenge for the user community. To enable efficient data compression without losing the potentiality of hyperspectral data, the noti...

Current state-of-the-art on-board image compression systems are based on the wavelet transform. However, redundancies can still be found between the wavelet coefficients. To exploit these remaining redundancies and increase the compression efficiency, the new post-transform compression scheme applies a second transform on blocks of coefficients. Th...

One of the main objectives of the Orfeo Toolbox (OTB) is the definition and the development of tools for the operational exploitation of the future sub-metric optic and radar images (rapid mapping, tridimensional aspects, change detection, texture analysis, pattern matching, optic and radar complementarities). The purpose of the OTB is to capitaliz...

La quantité de données produite par les capteurs hyperspectraux nécessite un algorithme de compression efficace qui restè a définir. Les propriétés statistiquesparticulì eres devraient permettre d'obtenir des algorithmes de compression efficaces Etant données ses propriétés et sa faible complexité, la transformée en ondelettes est un candidat prome...

For an efficient usage and distribution of high resolution satellite images, several problems need to be solved. The issue comes with the increasing size of these data. Constraints are different than those of the on-board compression, thus different solutions can be selected. For on-board compression, the main constraints are the computational comp...

Zerotrees of wavelet coefficients have shown a good adaptability for the compression of three dimensional images. EZW, the original algorithm using zerotree, shows good perfor- mance and was successfully adapted to 3D image compression. This paper focuses on the adaptation of EZW for the compression of hyperspectral images. The subordinate pass is...