15,963,927 members
Home / Discussions / Algorithms

# Algorithms

 Re: Threshholding ? David Crow24-Apr-07 3:39 David Crow 24-Apr-07 3:39
 Loop MoustafaS21-Apr-07 9:21 MoustafaS 21-Apr-07 9:21
 Re: Loop MoustafaS21-Apr-07 10:27 MoustafaS 21-Apr-07 10:27
 Re: Loop Frank Kerrigan2-May-07 5:45 Frank Kerrigan 2-May-07 5:45
 Image Recognition Algorithm softwaremonkey19-Apr-07 5:42 softwaremonkey 19-Apr-07 5:42
 Re: Image Recognition Algorithm Luc Pattyn19-Apr-07 6:24 Luc Pattyn 19-Apr-07 6:24
 Re: Image Recognition Algorithm [modified] Rilhas19-May-07 9:43 Rilhas 19-May-07 9:43
 Some ideas given here seem good, but they will tend to be computationally heavy. My work involves real time image processing in many domains, and in general most algorithms that are called "transform" are usually unacceptably slow (even for modern computers or DSP's). This, of course, depends on wether or not you can distribute the algorithm through various machines. In general I can't. Anyway, without more details on your case I simply imagine white sheets of paper with concentric circles drawn in them. If this is the case then finding the center is a very fast and efficient operation. Simply compute the mass center of all "pen" pixels. For example, if they are black then just sum the positions where you find them (keep X and Y separate) and in the end just divide the result by the image size. For example: mass_center_x=0; mass_center_y=0; total_found=0; for(y=0; y0) { mass_center_x/=total_found; mass_center_y/=total_found; } At this point the "mass_center_x" and "mass_center_y" contain the coordinates of the center of the concentric circles. This algorithm is very fast because each pixel is analyzed only once, and so runs in an amount of time directly proportional to the number of pixels. Also note that Y is the outer loop so as to exploit the CPU cache in the most efficient manner. I hope this helps, Rilhas -- modified at 8:28 Sunday 20th May, 2007
 help genetic algo clemzug15-Apr-07 1:12 clemzug 15-Apr-07 1:12
 Re: help genetic algo cp987615-Apr-07 2:31 cp9876 15-Apr-07 2:31
 Re: help genetic algo clemzug15-Apr-07 2:44 clemzug 15-Apr-07 2:44
 Re: help genetic algo cp987615-Apr-07 16:01 cp9876 15-Apr-07 16:01
 Re: help genetic algo Tim Craig15-Apr-07 18:08 Tim Craig 15-Apr-07 18:08
 Answer for this algorithm MoustafaS13-Apr-07 4:24 MoustafaS 13-Apr-07 4:24
 Re: Answer for this algorithm CPallini13-Apr-07 4:37 CPallini 13-Apr-07 4:37
 Re: Answer for this algorithm MoustafaS13-Apr-07 4:40 MoustafaS 13-Apr-07 4:40
 Re: Answer for this algorithm [modified] Leslie Sanford13-Apr-07 4:46 Leslie Sanford 13-Apr-07 4:46
 Re: Answer for this algorithm cp987613-Apr-07 4:47 cp9876 13-Apr-07 4:47
 Re: Answer for this algorithm MoustafaS13-Apr-07 4:51 MoustafaS 13-Apr-07 4:51
 Re: Answer for this algorithm cp987613-Apr-07 4:59 cp9876 13-Apr-07 4:59
 Re: Answer for this algorithm MoustafaS13-Apr-07 5:02 MoustafaS 13-Apr-07 5:02
 Skip List Indexing Leslie Sanford12-Apr-07 5:55 Leslie Sanford 12-Apr-07 5:55
 Re: Skip List Indexing Luc Pattyn12-Apr-07 9:30 Luc Pattyn 12-Apr-07 9:30
 Re: Skip List Indexing Leslie Sanford12-Apr-07 10:44 Leslie Sanford 12-Apr-07 10:44
 The Perfect Circle Bassam Abdul-Baki10-Apr-07 4:15 Bassam Abdul-Baki 10-Apr-07 4:15
 Last Visit: 31-Dec-99 18:00     Last Update: 9-Aug-24 20:52 Refresh ᐊ Prev1...256257258259260261262263264265 Next ᐅ