Color Models and Illumination Changes

Color model representation allows characterizing in a quantitative manner, any defined color spectrum of visible light, i.e. with a wavelength between 400nm and 700nm. To accomplish that, each model, or color space, is associated with a function that allows mapping the spectral power distribution of the visible electromagnetic radiation, in a space defined by a set of discrete values that quantify the color components composing the model. Some color spaces are sensitive to changes in lighting conditions. Others assure the preservation of certain chromatic features, remaining immune to these changes. Therefore, it becomes necessary to identify the strengths and weaknesses of each model in order to justify the adoption of color spaces in image processing and analysis techniques. This chapter will address the topic of digital imaging, main standards and formats. Next we will set the mathematical model of the image acquisition sensor response, which enables assessment of the various color spaces, with the aim of determining their invariance to illumination changes.

Money laundering and virtual money: the bitcoin example

Money laundering operations faced multiple changes and become more complex, in line with financial innovation. Often, regulation does not follow that innovation, giving opportunity to take advantage of thes e gaps in less lawful activities. The bitcoin is a virtual currency that has grown significantly, both in value and in volume of transactions, in recent years. The dimension of the phenomenon led to an increasing surveillance from the financial supervisors . We search for evidence of the relationship between money laundering and transactions carried out in bitcoins, the most popular virtual currency at the moment. We analyse the official publications relating the two themes, academic research and the notori ety within the international media. The attitudes toward the bitcoin are diverse, but all share concerns about its future impact. Some sparse evidence indicates that bitcoin may be an opportunity for money laundering, however more data is required.