If i've an image like : http://img836.imageshack.us/img836/6417/1zw.gif How can i identify the major two arcs in that image .
If the arcs can be modeled by y=(ax)^1/2 +b where a and b are constants such that a∈[250,400] and b∈[0,50] where b is an integer number as it represents the y-intercept of the arc in the image.
Output should be a 2-pixel thicker version of the detected arcs over the original image
May this will done by Hough Transform
Any Demo for doing that !please
Just filter out the grid points - they seem to be at fixed positions so it will be very easy to find them but just summing vertically and horizontally and look for high sums
verticalProfile = sum(grayImage, 2); horizontalProfile = sum(grayImage, 1); gridLocations = verticalProfile > 50; % or whatever. grayImage(gridLocations, :) = 0; % Make those rows black.
etc. doing the same for the vertical grid lines.....
Then you have just the curves. Find each one and use polyfit() or whatever.