1. A method for segmenting characters in a character string image, the method comprising the steps of determining a first starting point coordinate of a pixel contrasting to a background, generating a list of potential character widths dependent on a maximum character width and on characteristics of the portion of the character string image corresponding to the maximum character width, determining a second portion of the character string image corresponding to the first starting point coordinate and the first width on the list of potential character widths, applying a classification method on the second portion of the character string image providing a likelihood of error for the first width and a candidate character, comparing the likelihood of error with a first threshold determined by a trade-off between speed and accuracy; and selecting the candidate character as the character corresponding to the first width if the likelihood of error corresponding to the first width is lower than the threshold value.