Texture-based estimation of galactic properties

The aim is to test whether texture descriptors can extract novel information about physical quantities of galaxies, which normally require spectroscopy to determine. The specific star formation rate (sSFR) is chosen as the quantity in question. Methods We use three sets of features: • Colours from five bandpass filters (no texture information). • Gradient orientation histograms computed at 8 scales, σ. • Shape index histograms computed at 8 scales, σ. Gradient orientation (GO) • GO, θ(x, y; σ), represents first order differential structure. • It is weighted by the scale normalized gradient magnitude, M(x, y; σ). • It is binned to histograms with 8 bins. θ(x, y; σ) = arcta