Learning document image binarization from data

We present a fully trainable solution for binarization of degraded document images using extremely randomized trees. Unlike previous attempts that often use simple features, our method encodes all heuristics about whether or not a pixel is foreground text into a high-dimensional feature vector and learns a more complicated decision function. We introduce two novel features, the Logarithm Intensity Percentile (LIP) and the Relative Darkness Index (RDI), and combine them with low level features, and reformulated features from existing binarization methods. Experimental results show that using small sample size (about 1.5% of all available training data), we can achieve a binarization performance comparable to manually-tuned, state-of-the-art methods. Additionally, the trained document binarization classifier shows good generalization capabilities on out-of-domain data.