One of several improvements made to the word spotter was to use faster descriptor based on a few elements of the Fourier transform of radial lines with logarithmic sampling. This makes the descriptor much faster, but still robust enough. Actually, it must not be too precise as the shape of the words varies in the text. The figure shows three sample points to the left with the radial logarithmic sampling scheme (in red). Next is the result of the sampling and to the right is the resulting feature vector.
The sampling is done using a Gaussian mask so that sampling “between” pixels can be performed.
- Radial Line Fourier Descriptor for Handwritten Word Representation. Hast, A., Vats, E. Journal of WSCG, ISSN 1213-6972, vol 26, num 1. pp. 31-40. 2018.
@article{Has18a, author = {A. Hast and E. Vats}, title = {Radial Line Fourier descriptor for historical handwritten text representation}, journal = {Journal of WSCG, ISSN 1213-6972}, pages = {31--40}, volume = {26}, number = {1}, year = {2018}}
Anders Hast 