i want to detect circle in image and divide into 8 equal parts.and finally know the points where it cuts the circle

i want to detect circle in image and divide into 8 equal parts.and finally know the points where it cuts the circle

[Walter Roberson]

Explain the difference between this question and http://uk.mathworks.com/matlabcentral/answers/267265-dividing-a-circle-into-equal-8-parts-and-and-get-a-point-on-which-it-cuts-the-circle . If you were misunderstood in that other question why did you not respond with a clarification there instead of asking a new question?

[shikhar srivastava]

that question can only be implemented on circle with no background .i want to implement on image having circle. Basically i have image ,which i have uploaded .in this image i want to draw circle in a blank white space and then bisects the circle in 8 parts.and i want to know each points at which line touches the circles