Algorithms for the reduction of the number of points required to represent a digitized line or its caricature

Authors: David H Douglas, Thomas K Peucker

Comments:

1.

Summary:

This paper suggests resampling of sketch data.

* Resampling based on removing duplicate points - remove points which lie with in threshold distance. might remove points which are important.

* Resampling based on selecting point - E.g. Selecting every 6th point in a line. Might remove important points

*Resampling by calculating perpendicular distances -

- take 2 points - anchor and floating point. find the perpendicular distance between all the points lying between them and the line formed by them.

- find the maximum of the perpendicular distances. If it lies within a threshold, the anchor and floating point can be deemed to be a line.

- this anchor and floating points window is moved across the stroke.

Discussion: 

Effective way of resampling strokes without losing sensitive points. Success of the algorithm greatly depends on the threshold chosen to limit the perpendicular distances. 

This algorithm gives a method to perform a straight line test over a set of points. A similar one is used in the Wolin's algorithm too.