http://inperc.com/blog2/2007/10/12/lengths-of-digital-curves/ Computer vision, image analysis, and related mathematics Thu, 17 Feb 2011 13:25:51 +0000 hourly 1 http://wordpress.org/?v=3.1.3 http://inperc.com/blog2/2007/10/12/lengths-of-digital-curves/comment-page-1/#comment-19 Computer Vision for Dummies » Lengths of digital curves, part 4 Wed, 07 Nov 2007 15:21:54 +0000 http://inperc.com/blog2/2007/10/12/lengths-of-digital-curves/#comment-19 [...] From the three previous posts on the topic (Lengths of digital curves, parts 1, 2, 3) and a little presentation I gave recently I created an article for the wiki. In comparison, analysis is more extensive and there are more illustrations. At the end there are two examples of computation of roundness with Pixcavator 2.4. Circles have roundness close to 90, squares close to 80. It works quite well for large objects. You can now distinguish between circles and squares and between squares and elongated objects. For example, you have now a new way to automatically count (round) cells in the image and ignore (rough edged) noise. [...] [...] From the three previous posts on the topic (Lengths of digital curves, parts 1, 2, 3) and a little presentation I gave recently I created an article for the wiki. In comparison, analysis is more extensive and there are more illustrations. At the end there are two examples of computation of roundness with Pixcavator 2.4. Circles have roundness close to 90, squares close to 80. It works quite well for large objects. You can now distinguish between circles and squares and between squares and elongated objects. For example, you have now a new way to automatically count (round) cells in the image and ignore (rough edged) noise. [...]

]]> http://inperc.com/blog2/2007/10/12/lengths-of-digital-curves/comment-page-1/#comment-14 Computer Vision for Dummies » Lengths of digital curves, continued Sat, 20 Oct 2007 19:03:28 +0000 http://inperc.com/blog2/2007/10/12/lengths-of-digital-curves/#comment-14 [...] Recall that in the last post we observed that, since a curve in a digital image is represented as sequences of points, it is natural to think of its length as the total sum of distances between consecutive points. However, with this approach the length of a diagonally oriented segment will be overestimated by 40%. [...] [...] Recall that in the last post we observed that, since a curve in a digital image is represented as sequences of points, it is natural to think of its length as the total sum of distances between consecutive points. However, with this approach the length of a diagonally oriented segment will be overestimated by 40%. [...]

]]>