It’s possible.
Scan the digital picture pixel by pixel and line by line until you find the first line with two black pixels ( the adjacent pixels is counted as only one ),name the two pixels a1(xa1,ya1) and b1(xb1,yb2), continue scaning and you will get a2(xa2,ya2) and b2(xb2,yb2), a3(xa3,ya3) and b3(xb3,yb3). If (ya2-ya1)/(xa2-xa1) = (ya3-ya2)/(xa3-xa2) , then a1 is the first intersection. Store the coordenate of a1. Otherwise, b1 is the first intersection. Continue scanning, you will surely find the second intersection and the coordinate of the centre of the circle. Since you got the 3 point of the triangle, you can caculate the theta angle now. And finally, caculate the arc length by PI*r*r*(theta/360) _____ 发件人: [email protected] [mailto:[EMAIL PROTECTED] 代表 Daniel Bastidas 发送时间: 2008年1月4日 10:19 收件人: [email protected] 主题: [algogeeks] arc length Hi everybody. How can I find the arc length (L) in the picture attach if the only thing I know is the radio of circumference. I don´t know the coordenates of the intersection between line and circumference neither the theta angle. Any idea, it is possible...?. Thanks --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/algogeeks -~----------~----~----~----~------~----~------~--~---
