Created
June 22, 2017 21:12
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program blur | |
use pgmio | |
implicit none | |
double precision, parameter :: t=10.0d0, deltaT=0.2d0, k=5.0d0 | |
character*(*), parameter :: input='dif_tomography.pgm', output='dif_tomography_perona.pgm' | |
double precision, allocatable :: u(:,:), nu(:,:) | |
double precision :: north, south, east, west, level | |
integer :: w, h, offset, n, i, j | |
call pgmsize(input, w, h, offset) | |
allocate(u(0:w+1,0:h+1)) | |
u=0 | |
allocate(nu(w,h)) | |
call pgmread(input, offset, w, h, u, 0, 0) | |
level = 0 | |
do while (level<t) | |
do j=1,h | |
do i=1,w | |
north = u(i-1,j)-u(i,j) | |
south = u(i+1,j)-u(i,j) | |
east = u(i,j+1)-u(i,j) | |
west = u(i,j-1)-u(i,j) | |
nu(i,j) = u(i,j) + deltaT*(g(north)*north+g(south)*south+g(east)*east+g(west)*west) | |
end do | |
end do | |
u(1:w,1:h) = nu(1:w,1:h) | |
level = level + deltaT | |
end do | |
deallocate(u) | |
call pgmwriteheader(output, w, h) | |
call pgmappendbytes(output, nu, 1, 1) | |
deallocate(nu) | |
contains | |
function g(x) result(v) | |
implicit none | |
double precision, intent(in) :: x | |
double precision :: v | |
v = 1/(1+(x/k)**2) | |
end function g | |
end program blur |
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