Pansharpening of images acquired with color filter arrays

International audienceIn remote sensing, a common scenario involves the simultaneous acquisition of a panchromatic (PAN), a broad-band high spatial resolution image, and a multispectral (MS) image, which is composed of several spectral bands but at lower spatial resolution. The two sensors mounted on the same platform can be found in several very high spatial resolution optical remote sensing satellites for Earth observation (e.g., Quickbird, WorldView and SPOT) In this work we investigate an alternative acquisition strategy, which combines the information from both images into a single band image with the same number of pixels of the PAN. This operation allows to significantly reduce the burden of data downlink by achieving a fixed compression ratio of 1/(1 + b/ρ 2) compared to the conventional acquisition modes. Here, b and ρ denote the amount of distinct bands in the MS image and the scale ratio between the PAN and MS, respectively (e.g.: b = ρ = 4 as in many commercial high spatial resolution satellites). Many strategies can be conceived to generate such a compressed image from a given set of PAN and MS sources. A simple option, which will be presented here, is based on an application of the color filter array (CFA) theory. Specifically, the value of each pixel in the spatial support of the synthetic image is taken from the corresponding sample either in the PAN or in a given band of the MS upsampled to the size of the PAN. The choice is deterministic and done according to a custom mask. There are several works in the literature proposing various methods to construct masks which are able to preserve as much spectral content as possible for conventional RGB images. However, those results are not directly applicable to the case at hand, since it deals with i) images with different spatial resolution, ii) potentially more than three spectral bands and, iii) in general, different radiometric dynamics across bands. A tentative approach to address these issues is presented in this work. The compressed image resulting from the proposed acquisition strategy will be processed to generate an image featuring both the spatial resolution of the PAN and the spectral bands of the MS. This final product allows a direct comparison with the result of any standard pansharpening algorithm; the latter refers to a specific instance of data fusion (i.e., fusion of a PAN and MS image), which differs from our scenario since both sources are separately taken as input. In our setting, the fusion step performed at the ground segment will jointly involve a fusion and reconstruction problem (also known as demosaicing in the CFA literature). We propose to address this problem with a variational approach. We present in this work preliminary results related to the proposed scheme on real remote sensed images, tested over two different datasets acquired by the Quickbird and Geoeye-1 platforms, which show superior performances compared to applying a basic radiometric compression algorithm to both sources before performing a pansharpening protocol. The validation of the final products in both scenarios allows to visually and numerically appreciate the tradeoff between the compression of the source data and the quality loss suffered

Joint demosaicing and fusion of multiresolution coded acquisitions: A unified image formation and reconstruction method

Novel optical imaging devices allow for hybrid acquisition modalities such as compressed acquisitions with locally different spatial and spectral resolutions captured by a single focal plane array. In this work, we propose to model the capturing system of a multiresolution coded acquisition (MRCA) in a unified framework, which natively includes conventional systems such as those based on spectral/color filter arrays, compressed coded apertures, and multiresolution sensing. We also propose a model-based image reconstruction algorithm performing a joint demosaicing and fusion (JoDeFu) of any acquisition modeled in the MRCA framework. The JoDeFu reconstruction algorithm solves an inverse problem with a proximal splitting technique and is able to reconstruct an uncompressed image datacube at the highest available spatial and spectral resolution. An implementation of the code is available at https://github.com/danaroth83/jodefu.Comment: 15 pages, 7 figures; regular pape

Image fusion and reconstruction of compressed data: A joint approach

International audienceIn the context of data fusion, pansharpening refers to the combination of a panchromatic (PAN) and a multispectral (MS) image, aimed at generating an image that features both the high spatial resolution of the former and high spectral diversity of the latter. In this work we present a model to jointly solve the problem of data fusion and reconstruction of a compressed image; the latter is envisioned to be generated solely with optical on-board instruments, and stored in place of the original sources. The burden of data downlink is hence significantly reduced at the expense of a more laborious analysis done at the ground segment to estimate the missing information. The reconstruction algorithm estimates the target sharpened image directly instead of decompressing the original sources beforehand; a viable and practical novel solution is also introduced to show the effectiveness of the approach

Wellbeing and Inclusion : Closeness in the Distance = Benessere e inlcusione: presenza nella distanza

L’inclusione scolastica, quale processo teso a strutturare dinamiche dialogiche e di partecipazione per tutti, non può essere ridotta ai soli interventi compensativi per l’apprendimento degli alunni con bisogni educativi speciali. In tal senso, la professionalità degli insegnanti assume un ruolo centrale quale supporto consapevole e attento alle diverse dimensioni del benessere. L’analisi di una serie di interviste rivolte ad un team di docenti della scuola primaria coinvolto in un progetto di ricerca-formazione evidenzia le attenzioni didattico-metodologiche e le consapevolezze professionali che, durante i percorsi di DAD, hanno permesso alle insegnanti di realizzare un concreto processo di inclusione e un ambiente di benessere per alunni e famiglie.As a process aimed to enhance dialogical and participative dynamics for all, school inclusion cannot be reduced to a mere provision of learning compensatory measures for pupils with special educational needs. In this sense, teachers’ professionalism takes a critical role as an aware and careful support towards the many dimensions of wellbeing. The analysis of the interviews, carried out with a primary school team of teachers involved in a research-training project, highlights the didactics attentions and the professional awareness that, during remote schooling, has allowed teachers to accomplish a concrete process of inclusion, and a wellbeing environment for pupils and families

Prospettive trasformative di educazione genitoriale: itinerari di sviluppo e traiettorie teorico-operative

Disability can modify family structure in organizational, relational and emotional terms and affect significantly parenting skills and resources. For this reason, it becomes relevant to prepare and implement effective interventions to help parents to face challenges, in order to support those inclusive processes with which families, schools and the whole society are called to confront themselves in a dynamic and continuous intervention, research and training. Through a review of the international literature, this paper presents the results of a qualitative research that highlights in what terms and in what ways, within the paradigm of adult education, the transformative approach has found concrete application in parent education. The review, conducted on ten studies, aimed to explore parents’ experiences and perceptions of parenting programs. Three main themes were identified: (1) parental transformation, (2) educational device and (3) parents transitions. Results reveal an intervention model that can affect meaning perspectives and educational and parenting practices, in line with transformative learning theory

The construction-development curve: evidence from a new international dataset

Using a new dataset of construction investment in world countries for the period 2000- 2011, this article provides novel evidence of a bell-shaped relationship between the share of construction in GDP and economic development. The relative level of construction activity tends to increase in developing countries, to peak during industrialization and to decrease at a slowing pace in industrialized countries, approaching stabilization in mature economies. The curve fits better if economic development is measured by alternative indicators instead of per-capita GDP, namely life expectancy and an Economic Development Index (EDI) which takes into account per capita income, life expectancy, maternal mortality ratio and the share of agriculture in employment. On average, the peak in construction activity is reached at a per capita income level of almost 5,000 Euro (PPP, 2011 prices), or when life expectancy in the country has reached around 67 years. At its peak, construction accounts for about 14% of a country's GDP. The curve is robust to the inclusion of control variables. Population density, demographic growth and credit expansion don't explain cross-country variation in the share of construction in output, while there is weak evidence that a less concentrated income distribution is positively related to the size of the construction sector

The construction-development curve: evidence from a new international dataset

Using a new dataset of construction investment in world countries for the period 2000- 2011, this article provides novel evidence of a bell-shaped relationship between the share of construction in GDP and economic development. The relative level of construction activity tends to increase in developing countries, to peak during industrialization and to decrease at a slowing pace in industrialized countries, approaching stabilization in mature economies. The curve fits better if economic development is measured by alternative indicators instead of per-capita GDP, namely life expectancy and an Economic Development Index (EDI) which takes into account per capita income, life expectancy, maternal mortality ratio and the share of agriculture in employment. On average, the peak in construction activity is reached at a per capita income level of almost 5,000 Euro (PPP, 2011 prices), or when life expectancy in the country has reached around 67 years. At its peak, construction accounts for about 14% of a country's GDP. The curve is robust to the inclusion of control variables. Population density, demographic growth and credit expansion don't explain cross-country variation in the share of construction in output, while there is weak evidence that a less concentrated income distribution is positively related to the size of the construction sector

Model-based demosaicking for acquisitions by a RGBW color filter array

Microsatellites and drones are often equipped with digital cameras whose sensing system is based on color filter arrays (CFAs), which define a pattern of color filter overlaid over the focal plane. Recent commercial cameras have started implementing RGBW patterns, which include some filters with a wideband spectral response together with the more classical RGB ones. This allows for additional light energy to be captured by the relevant pixels and increases the overall SNR of the acquisition. Demosaicking defines reconstructing a multi-spectral image from the raw image and recovering the full color components for all pixels. However, this operation is often tailored for the most widespread patterns, such as the Bayer pattern. Consequently, less common patterns that are still employed in commercial cameras are often neglected. In this work, we present a generalized framework to represent the image formation model of such cameras. This model is then exploited by our proposed demosaicking algorithm to reconstruct the datacube of interest with a Bayesian approach, using a total variation regularizer as prior. Some preliminary experimental results are also presented, which apply to the reconstruction of acquisitions of various RGBW cameras

Metaverse between object and metaphor: possible scenarios for inclusion

The metaverse is a complex concept, the use of which has evolved beyond Stephenson's 1992 vision, including aspects of the physical world, objects, actors, interfaces and networks that build and interact with virtual environments. Over the past year, the metaverse has stimulated interest in several fields of knowledge (Computer Science, Engineering, Social Sciences, Economics just to name a few), becoming an inter-intra disciplinary suitcase word. Starting with a brief historical overview that traces the prodromes and definitions of this extension of reality in a descriptive manner, this contribution problematizes the phenomenon from an inclusive perspective, outlining a dual characterization: on the one hand, the metaverse as object, on the other, as metaphor. This last aspect prompts further reflection, raising questions about both the use of technology for educational purposes, and possible future scenarios, in relation to key aspects such as accessibility and data privacy

Interferometer response characterization algorithm for multi-aperture Fabry-Perot imaging spectrometers

In recent years, the demand for hyperspectral imaging devices has grown significantly, driven by their ability of capturing high-resolution spectral information. Among the several possible optical designs for acquiring hyperspectral images, there is a growing interest in interferometric spectral imaging systems based on division of aperture. These systems have the advantage of capturing snapshot acquisitions while maintaining a compact design. However, they require a careful calibration to operate properly. In this work, we present the interferometer response characterization algorithm (IRCA), a robust three-step procedure designed to characterize the transmittance response of multi-aperture imaging spectrometers based on the interferometry of Fabry-Perot. Additionally, we propose a formulation of the image formation model for such devices suitable to estimate the parameters of interest by considering the model under various regimes of finesse. The proposed algorithm processes the image output obtained from a set of monochromatic light sources and refines the results using nonlinear regression after an ad-hoc initialization. Through experimental analysis conducted on four different prototypes from the Image SPectrometer On Chip (ImSPOC) family, we validate the performance of our approach for characterization. The associated source code for this paper is available at https://github.com/danaroth83/irca.Comment: 20 pages, 11 figures. (Revised structure, added experiments