ICDAR2009 Handwriting Segmentation Contest
Click on thumbnails to see the actual images.
Method Description for Line Segmentation
First the input image is sub-sampled by a factor of four in both dimensions while turning it into a gray-level image:
Then an anisotropic Gaussian filtering is applied (mainly horizontal). In the resulting fuzzy image, lines appear as dark shapes, that are regional minima:
The morphological watershed transform is computed, leading into a partition of the image into regions. Those regions form an over-segmentation of text lines. In the picture below, the watershed line is depicted in red, superimposed over the fuzzy image.
To obtain the segmentation into lines, a simple merging procedure is run on the region adjacency graph. Below, lines are colorized and depicted over the resized input image; the watershed line is shown in white.
Eventually a cleaning routine is applied to provide the final labeling image.
Method Description for Word Segmentation
First the input image is downsized and inverted.
Second a morphological structural closing is applied with a rectangle as structural element.
From the input image a distance map to characters is computed. An attribute morphological closing is then applied to merge altogether non-significant regional minima.
Last the morphological watershed transform is computed to obtain the segmentation into words. The watershed line is depicted below in red over the reduced input image.
The source code will be available on June 2009...