bounding_box_grouping_function

bool bounding_box_grouping_function (Rect a, Rect b, int threshold)

Given two rectangles a, b, and a given threshold distance (in pixels), returns True if the two rectangles are closer than threshold.

edit_distance

int edit_distance (str s1, str s2)

Computes the edit distance (also known as Levenshtein distance) between two strings.

This counts the number of character substitutions, additions and deletions necessary to transform one string into another. This plugin is a straightforward implementation of the classic algorithm by Wagner and Fischer, which has runtime complexity O(m*n), where m and n are the lengths of the two strings.

See R.A. Wagner, M.J. Fischer: The String-to-String Correction Problem. Journal of the ACM 21, pp. 168-173, 1974.

least_squares_fit

object least_squares_fit ([object points])

Performs a least squares fit on a given list of points.

The result is a tuple of the form (m, b, q) where m is the slope of the line, b is the y-offset, and q is the gamma fit of the line to the points. (This assumes the same statistical significance for all points).

See Numerical Recipes in C, section 15.2 for more information.

least_squares_fit_xy

object least_squares_fit_xy ([object points])

Identical to least_squares_fit for line angles below 45 degrees. For lines with a more vertical slope a least square fit of x = my + b is done instead.

The result is a tuple of the form (m, b, q, x_of_y) where m, b, q are the same as in least_squares_fit, but the integer value x_of_y determines the actual meaning of the parameters m and b:

When x_of_y is zero, y = mx + b. Otherwise x = my + b.

polar_distance

FloatVector polar_distance (Image [OneBit|GreyScale|Grey16|RGB|Float|Complex] other)

Returns a tuple containing the normalized distance, polar direction, and non-normalized polar distance to another glyph (based on center of bounding boxes).

polar_match

int polar_match (float r1, float q1, float r2, float q2)

shaped_grouping_function

bool shaped_grouping_function (Image [OneBit] a, Image [OneBit] b, int threshold)

Given two connected components a, b, and a given threshold distance (in pixels), returns True if any pixel in a are closer than threshold to any pixel in b.