Hi everyone,
I am trying to apply gabor filter to a fingerprint for fingerprint enhancement using c.
My image size is 280x340.Gabor filter equation is :

F(x,y) = exp(-0.5*[x^2/sigma_x^2 + y^2/sigma_y^2]) * cos(2*PI*f*x);

I am able to execute this equation.But my problem is i am calculating the equation for 280x340 times and it is taking time(4 sec 2.93GHz 3GB ram).

Can any one told me how to reduce the executation time ?
What I know exp function is taking time. So is there any equivalent of exp which will take less time to execute ?

tanks in advance.