Fig. 3

Binarization of reconstructed micro-CT images. Gray-scale reconstructed 2D image of a silk-based tissue engineering scaffold with a circular region of interest (ø 3 mm) (a), half-tone views (b, d, and f) and the corresponding binary images (c, e, and g) respectively if no gray-scale value is included that yields to complete black, if entire gray-scale values are included that yields to complete white, and if the right gray-scale values (that is in this case 38-255) are obtained by global thresholding that yields to a binary image showing the microstructure of the scaffold