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EPFL   Student Projects: Florent Cosandier
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Quantitative measure of chromatin condensation in 4D

Florent Cosandier
Section Microtechnique, EPFL

Semester project
February 2006

The goal of that project is to find a measure that correlates well the level of condensation of the chromatin by 4D imaging. The biologist do this judgment all days by eye, but the motivation is to improve an algorithm that make this judgment. (prophase-interphase)
Some statistical tests are made like the energy (most common measure realized by biologists), gradient energy, variance. Other tests are also made : optimal (in the least square sense) quantization ; for look in the relative level occupation of the gray levels. The last test is measure of the alpha parameter of the decreasing of the PSD (power spectral density). All measures give a curve that is fitted with a mathematical model. This fitting return one two or three parameters that contains the most part of the information about the brut 4D data. Other possibilities are available like the wavelets decomposition or granulometric analysis.