void
project(
float *obj, int ox, int oy, int oz,
float *data, int dx, int dy, int dz, float *center, float *theta,
int istart, int iend)
{
float *gridx = (float *)malloc((oy+1)*sizeof(float));
float *gridy = (float *)malloc((oz+1)*sizeof(float));
float *coordx = (float *)malloc((oz+1)*sizeof(float));
float *coordy = (float *)malloc((oy+1)*sizeof(float));
float *ax = (float *)malloc((oy+oz)*sizeof(float));
float *ay = (float *)malloc((oy+oz)*sizeof(float));
float *bx = (float *)malloc((oy+oz)*sizeof(float));
float *by = (float *)malloc((oy+oz)*sizeof(float));
float *coorx = (float *)malloc((oy+oz)*sizeof(float));
float *coory = (float *)malloc((oy+oz)*sizeof(float));
float *dist = (float *)malloc((oy+oz)*sizeof(float));
int *indi = (int *)malloc((oy+oz)*sizeof(int));
assert(coordx != NULL && coordy != NULL &&
ax != NULL && ay != NULL && by != NULL && bx != NULL &&
coorx != NULL && coory != NULL && dist != NULL && indi != NULL);
int s, p, d;
int quadrant;
float theta_p, sin_p, cos_p;
float mov, xi, yi;
int asize, bsize, csize;
preprocessing(oy, oz, dz, center[0],
&mov, gridx, gridy); // Outputs: mov, gridx, gridy
// For each projection angle
for (p=istart; p<iend; p++)
{
// Calculate the sin and cos values
// of the projection angle and find
// at which quadrant on the cartesian grid.
theta_p = fmod(theta[p], 2*M_PI);
quadrant = calc_quadrant(theta_p);
sin_p = sinf(theta_p);
cos_p = cosf(theta_p);
for (d=0; d<dz; d++)
{
// Calculate coordinates
xi = -oy-oz;
yi = (1-dz)/2.0+d+mov;
calc_coords(
oy, oz, xi, yi, sin_p, cos_p, gridx, gridy,
coordx, coordy);
// Merge the (coordx, gridy) and (gridx, coordy)
trim_coords(
oy, oz, coordx, coordy, gridx, gridy,
&asize, ax, ay, &bsize, bx, by);
// Sort the array of intersection points (ax, ay) and
// (bx, by). The new sorted intersection points are
// stored in (coorx, coory). Total number of points
// are csize.
sort_intersections(
quadrant, asize, ax, ay, bsize, bx, by,
&csize, coorx, coory);
// Calculate the distances (dist) between the
// intersection points (coorx, coory). Find the
// indices of the pixels on the object grid.
calc_dist(
oy, oz, csize, coorx, coory,
indi, dist);
// For each slice
for (s=0; s<dy; s++)
{
// Calculate simdata
calc_simdata(p, s, d, oy, oz, dy, dz,
csize, indi, dist, obj,
data); // Output: simulated data
}
}
}
free(gridx);
free(gridy);
free(coordx);
free(coordy);
free(ax);
free(ay);
free(bx);
free(by);
free(coorx);
free(coory);
free(dist);
free(indi);
}
void
ospml_hybrid(const float* data, int dy, int dt, int dx, const float* center,
const float* theta, float* recon, int ngridx, int ngridy, int num_iter,
const float* reg_pars, int num_block, const float* ind_block)
{
if(dy == 0 || dt == 0 || dx == 0)
return;
float* gridx = (float*) malloc((ngridx + 1) * sizeof(float));
float* gridy = (float*) malloc((ngridy + 1) * sizeof(float));
float* coordx = (float*) malloc((ngridy + 1) * sizeof(float));
float* coordy = (float*) malloc((ngridx + 1) * sizeof(float));
float* ax = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* ay = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* bx = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* by = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* coorx = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* coory = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* dist = (float*) malloc((ngridx + ngridy) * sizeof(float));
int* indi = (int*) malloc((ngridx + ngridy) * sizeof(int));
assert(coordx != NULL && coordy != NULL && ax != NULL && ay != NULL && by != NULL &&
bx != NULL && coorx != NULL && coory != NULL && dist != NULL && indi != NULL);
int s, q, p, d, i, m, n, os;
int quadrant;
float theta_p, sin_p, cos_p;
float mov, xi, yi;
int asize, bsize, csize;
float* simdata;
float upd;
int ind_data, ind_recon;
float* sum_dist;
float sum_dist2;
float *E, *F, *G;
int ind0, ind1, indg[8];
float totalwg, wg[8], mg[8], rg[8], gammag[8];
int subset_ind1, subset_ind2;
for(i = 0; i < num_iter; i++)
{
simdata = (float*) calloc((dt * dy * dx), sizeof(float));
// For each slice
for(s = 0; s < dy; s++)
{
preprocessing(ngridx, ngridy, dx, center[s], &mov, gridx,
gridy); // Outputs: mov, gridx, gridy
subset_ind1 = dt / num_block;
subset_ind2 = subset_ind1;
// For each ordered-subset num_subset
for(os = 0; os < num_block + 1; os++)
{
if(os == num_block)
{
subset_ind2 = dt % num_block;
}
sum_dist = (float*) calloc((ngridx * ngridy), sizeof(float));
E = (float*) calloc((ngridx * ngridy), sizeof(float));
F = (float*) calloc((ngridx * ngridy), sizeof(float));
G = (float*) calloc((ngridx * ngridy), sizeof(float));
// For each projection angle
for(q = 0; q < subset_ind2; q++)
{
p = ind_block[q + os * subset_ind1];
// Calculate the sin and cos values
// of the projection angle and find
// at which quadrant on the cartesian grid.
theta_p = fmodf(theta[p], 2.0f * (float) M_PI);
quadrant = calc_quadrant(theta_p);
sin_p = sinf(theta_p);
cos_p = cosf(theta_p);
// For each detector pixel
for(d = 0; d < dx; d++)
{
// Calculate coordinates
xi = -ngridx - ngridy;
yi = 0.5f * (1 - dx) + d + mov;
calc_coords(ngridx, ngridy, xi, yi, sin_p, cos_p, gridx, gridy,
coordx, coordy);
// Merge the (coordx, gridy) and (gridx, coordy)
trim_coords(ngridx, ngridy, coordx, coordy, gridx, gridy, &asize,
ax, ay, &bsize, bx, by);
// Sort the array of intersection points (ax, ay) and
// (bx, by). The new sorted intersection points are
// stored in (coorx, coory). Total number of points
// are csize.
sort_intersections(quadrant, asize, ax, ay, bsize, bx, by, &csize,
coorx, coory);
// Calculate the distances (dist) between the
// intersection points (coorx, coory). Find the
// indices of the pixels on the reconstruction grid.
calc_dist(ngridx, ngridy, csize, coorx, coory, indi, dist);
// Calculate simdata
calc_simdata(s, p, d, ngridx, ngridy, dt, dx, csize, indi, dist,
recon,
simdata); // Output: simdata
// Calculate dist*dist
sum_dist2 = 0.0f;
for(n = 0; n < csize - 1; n++)
{
sum_dist2 += dist[n] * dist[n];
sum_dist[indi[n]] += dist[n];
}
// Update
if(sum_dist2 != 0.0f)
{
ind_data = d + p * dx + s * dt * dx;
ind_recon = s * ngridx * ngridy;
upd = data[ind_data] / simdata[ind_data];
for(n = 0; n < csize - 1; n++)
{
E[indi[n]] -= recon[indi[n] + ind_recon] * upd * dist[n];
}
}
}
}
// Weights for inner neighborhoods.
totalwg = 4 + 4 / sqrt(2);
wg[0] = 1 / totalwg;
wg[1] = 1 / totalwg;
wg[2] = 1 / totalwg;
wg[3] = 1 / totalwg;
wg[4] = 1 / sqrt(2) / totalwg;
wg[5] = 1 / sqrt(2) / totalwg;
wg[6] = 1 / sqrt(2) / totalwg;
wg[7] = 1 / sqrt(2) / totalwg;
// (inner region)
for(n = 1; n < ngridx - 1; n++)
{
for(m = 1; m < ngridy - 1; m++)
{
ind0 = m + n * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 - 1;
indg[2] = ind1 + ngridy;
indg[3] = ind1 - ngridy;
indg[4] = ind1 + ngridy + 1;
indg[5] = ind1 + ngridy - 1;
indg[6] = ind1 - ngridy + 1;
indg[7] = ind1 - ngridy - 1;
for(q = 0; q < 8; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
}
}
// Weights for edges.
totalwg = 3 + 2 / sqrt(2);
wg[0] = 1 / totalwg;
wg[1] = 1 / totalwg;
wg[2] = 1 / totalwg;
wg[3] = 1 / sqrt(2) / totalwg;
wg[4] = 1 / sqrt(2) / totalwg;
// (top)
for(m = 1; m < ngridy - 1; m++)
{
ind0 = m;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 - 1;
indg[2] = ind1 + ngridy;
indg[3] = ind1 + ngridy + 1;
indg[4] = ind1 + ngridy - 1;
for(q = 0; q < 5; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
}
// (bottom)
for(m = 1; m < ngridy - 1; m++)
{
ind0 = m + (ngridx - 1) * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 - 1;
indg[2] = ind1 - ngridy;
indg[3] = ind1 - ngridy + 1;
indg[4] = ind1 - ngridy - 1;
for(q = 0; q < 5; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
}
// (left)
for(n = 1; n < ngridx - 1; n++)
{
ind0 = n * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 + ngridy;
indg[2] = ind1 - ngridy;
indg[3] = ind1 + ngridy + 1;
indg[4] = ind1 - ngridy + 1;
for(q = 0; q < 5; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
}
// (right)
for(n = 1; n < ngridx - 1; n++)
{
ind0 = (ngridy - 1) + n * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 - 1;
indg[1] = ind1 + ngridy;
indg[2] = ind1 - ngridy;
indg[3] = ind1 + ngridy - 1;
indg[4] = ind1 - ngridy - 1;
for(q = 0; q < 5; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
}
// Weights for corners.
totalwg = 2 + 1 / sqrt(2);
wg[0] = 1 / totalwg;
wg[1] = 1 / totalwg;
wg[2] = 1 / sqrt(2) / totalwg;
// (top-left)
ind0 = 0;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 + ngridy;
indg[2] = ind1 + ngridy + 1;
for(q = 0; q < 3; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
// (top-right)
ind0 = (ngridy - 1);
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 - 1;
indg[1] = ind1 + ngridy;
indg[2] = ind1 + ngridy - 1;
for(q = 0; q < 3; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
// (bottom-left)
ind0 = (ngridx - 1) * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 + 1;
indg[1] = ind1 - ngridy;
indg[2] = ind1 - ngridy + 1;
for(q = 0; q < 3; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
// (bottom-right)
ind0 = (ngridy - 1) + (ngridx - 1) * ngridy;
ind1 = ind0 + s * ngridx * ngridy;
indg[0] = ind1 - 1;
indg[1] = ind1 - ngridy;
indg[2] = ind1 - ngridy - 1;
for(q = 0; q < 3; q++)
{
mg[q] = recon[ind1] + recon[indg[q]];
rg[q] = recon[ind1] - recon[indg[q]];
gammag[q] = 1 / (1 + fabs(rg[q] / reg_pars[1]));
F[ind0] += 2 * reg_pars[0] * wg[q] * gammag[q];
G[ind0] -= 2 * reg_pars[0] * wg[q] * gammag[q] * mg[q];
}
q = 0;
for(n = 0; n < ngridx * ngridy; n++)
{
G[q] += sum_dist[n];
q++;
}
for(n = 0; n < ngridx; n++)
{
for(m = 0; m < ngridy; m++)
{
q = m + n * ngridy;
if(F[q] != 0.0)
{
ind0 = q + s * ngridx * ngridy;
recon[ind0] = (-G[q] + sqrt(G[q] * G[q] - 8 * E[q] * F[q])) /
(4 * F[q]);
}
}
}
free(sum_dist);
free(E);
free(F);
free(G);
}
}
free(simdata);
}
free(gridx);
free(gridy);
free(coordx);
free(coordy);
free(ax);
free(ay);
free(bx);
free(by);
free(coorx);
free(coory);
free(dist);
free(indi);
}
void
fbp(
float *data, int dx, int dy, int dz, float *center, float *theta,
float *recon, int ngridx, int ngridy, char *fname,
int istart, int iend)
{
float *gridx = (float *)malloc((ngridx+1)*sizeof(float));
float *gridy = (float *)malloc((ngridy+1)*sizeof(float));
float *coordx = (float *)malloc((ngridy+1)*sizeof(float));
float *coordy = (float *)malloc((ngridx+1)*sizeof(float));
float *ax = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *ay = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *bx = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *by = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *coorx = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *coory = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *dist = (float *)malloc((ngridx+ngridy)*sizeof(float));
int *indi = (int *)malloc((ngridx+ngridy)*sizeof(int));
assert(coordx != NULL && coordy != NULL &&
ax != NULL && ay != NULL && by != NULL && bx != NULL &&
coorx != NULL && coory != NULL && dist != NULL && indi != NULL);
int s, p, d, n;
int quadrant;
float theta_p, sin_p, cos_p;
float mov, xi, yi;
int asize, bsize, csize;
float* simdata;
int ind_data, ind_recon;
simdata = (float *)calloc((dx*dy*dz), sizeof(float));
// For each slice
for (s=istart; s<iend; s++)
{
preprocessing(ngridx, ngridy, dz, center[s],
&mov, gridx, gridy); // Outputs: mov, gridx, gridy
// For each projection angle
for (p=0; p<dx; p++)
{
// Calculate the sin and cos values
// of the projection angle and find
// at which quadrant on the cartesian grid.
theta_p = fmod(theta[p], 2*M_PI);
quadrant = calc_quadrant(theta_p);
sin_p = sinf(theta_p);
cos_p = cosf(theta_p);
// For each detector pixel
for (d=0; d<dz; d++)
{
// Calculate coordinates
xi = -ngridx-ngridy;
yi = (1-dz)/2.0+d+mov;
calc_coords(
ngridx, ngridy, xi, yi, sin_p, cos_p, gridx, gridy,
coordx, coordy);
// Merge the (coordx, gridy) and (gridx, coordy)
trim_coords(
ngridx, ngridy, coordx, coordy, gridx, gridy,
&asize, ax, ay, &bsize, bx, by);
// Sort the array of intersection points (ax, ay) and
// (bx, by). The new sorted intersection points are
// stored in (coorx, coory). Total number of points
// are csize.
sort_intersections(
quadrant, asize, ax, ay, bsize, bx, by,
&csize, coorx, coory);
// Calculate the distances (dist) between the
// intersection points (coorx, coory). Find the
// indices of the pixels on the reconstruction grid.
calc_dist(
ngridx, ngridy, csize, coorx, coory,
indi, dist);
// Calculate simdata
calc_simdata(p, s, d, ngridx, ngridy, dy, dz,
csize, indi, dist, recon,
simdata); // Output: simdata
// Calculate dist*dist
float sum_dist2 = 0.0;
for (n=0; n<csize-1; n++)
{
sum_dist2 += dist[n]*dist[n];
}
// Update
if (sum_dist2 != 0.0)
{
ind_recon = s*ngridx*ngridy;
ind_data = d+s*dz+p*dy*dz;
for (n=0; n<csize-1; n++)
{
recon[indi[n]+ind_recon] += data[ind_data]*dist[n];
}
}
}
}
}
free(simdata);
free(gridx);
free(gridy);
free(coordx);
free(coordy);
free(ax);
free(ay);
free(bx);
free(by);
free(coorx);
free(coory);
free(dist);
free(indi);
}
void
bart(
float *data, int dx, int dy, int dz, float *center, float *theta,
float *recon, int ngridx, int ngridy, int num_iter,
int num_block, float *ind_block)
{
float *gridx = (float *)malloc((ngridx+1)*sizeof(float));
float *gridy = (float *)malloc((ngridy+1)*sizeof(float));
float *coordx = (float *)malloc((ngridy+1)*sizeof(float));
float *coordy = (float *)malloc((ngridx+1)*sizeof(float));
float *ax = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *ay = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *bx = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *by = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *coorx = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *coory = (float *)malloc((ngridx+ngridy)*sizeof(float));
float *dist = (float *)malloc((ngridx+ngridy)*sizeof(float));
int *indi = (int *)malloc((ngridx+ngridy)*sizeof(int));
assert(coordx != NULL && coordy != NULL &&
ax != NULL && ay != NULL && by != NULL && bx != NULL &&
coorx != NULL && coory != NULL && dist != NULL && indi != NULL);
int s, q, p, d, i, m, n, os;
int quadrant;
float theta_p, sin_p, cos_p;
float mov, xi, yi;
int asize, bsize, csize;
float *simdata;
float upd;
int ind_data, ind_recon;
float *sum_dist;
float sum_dist2;
float *update;
int subset_ind1, subset_ind2;
for (i=0; i<num_iter; i++)
{
simdata = (float *)calloc((dx*dy*dz), sizeof(float));
// For each slice
for (s=0; s<dy; s++)
{
preprocessing(ngridx, ngridy, dz, center[s],
&mov, gridx, gridy); // Outputs: mov, gridx, gridy
subset_ind1 = dx/num_block;
subset_ind2 = subset_ind1;
// For each ordered-subset num_subset
for (os=0; os<num_block+1; os++)
{
if (os == num_block)
{
subset_ind2 = dx%num_block;
}
sum_dist = (float *)calloc((ngridx*ngridy), sizeof(float));
update = (float *)calloc((ngridx*ngridy), sizeof(float));
// For each projection angle
for (q=0; q<subset_ind2; q++)
{
p = ind_block[q+os*subset_ind1];
// Calculate the sin and cos values
// of the projection angle and find
// at which quadrant on the cartesian grid.
theta_p = fmod(theta[p], 2*M_PI);
quadrant = calc_quadrant(theta_p);
sin_p = sinf(theta_p);
cos_p = cosf(theta_p);
// For each detector pixel
for (d=0; d<dz; d++)
{
// Calculate coordinates
xi = -1e6;
yi = -(dz-1)/2.0+d+mov;
calc_coords(
ngridx, ngridy, xi, yi, sin_p, cos_p, gridx, gridy,
coordx, coordy);
// Merge the (coordx, gridy) and (gridx, coordy)
trim_coords(
ngridx, ngridy, coordx, coordy, gridx, gridy,
&asize, ax, ay, &bsize, bx, by);
// Sort the array of intersection points (ax, ay) and
// (bx, by). The new sorted intersection points are
// stored in (coorx, coory). Total number of points
// are csize.
sort_intersections(
quadrant, asize, ax, ay, bsize, bx, by,
&csize, coorx, coory);
// Calculate the distances (dist) between the
// intersection points (coorx, coory). Find the
// indices of the pixels on the reconstruction grid.
calc_dist(
ngridx, ngridy, csize, coorx, coory,
indi, dist);
// Calculate simdata
calc_simdata(p, s, d, ngridx, ngridy, dy, dz,
csize, indi, dist, recon,
simdata); // Output: simdata
// Calculate dist*dist
sum_dist2 = 0.0;
for (n=0; n<csize-1; n++)
{
sum_dist2 += dist[n]*dist[n];
sum_dist[indi[n]] += dist[n];
}
// Update
if (sum_dist2 != 0.0)
{
ind_data = d+s*dz+p*dy*dz;
upd = (data[ind_data]-simdata[ind_data])/sum_dist2;
for (n=0; n<csize-1; n++)
{
update[indi[n]] += upd*dist[n];
}
}
}
}
m = 0;
for (n = 0; n < ngridx*ngridy; n++) {
if (sum_dist[n] != 0.0) {
ind_recon = s*ngridx*ngridy;
recon[m+ind_recon] += update[m]/sum_dist[n];
}
m++;
}
free(sum_dist);
free(update);
}
}
free(simdata);
}
free(gridx);
free(gridy);
free(coordx);
free(coordy);
free(ax);
free(ay);
free(bx);
free(by);
free(coorx);
free(coory);
free(dist);
free(indi);
}
void
art(const float* data, int dy, int dt, int dx, const float* center, const float* theta,
float* recon, int ngridx, int ngridy, int num_iter)
{
if(dy == 0 || dt == 0 || dx == 0)
return;
float* gridx = (float*) malloc((ngridx + 1) * sizeof(float));
float* gridy = (float*) malloc((ngridy + 1) * sizeof(float));
float* coordx = (float*) malloc((ngridy + 1) * sizeof(float));
float* coordy = (float*) malloc((ngridx + 1) * sizeof(float));
float* ax = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* ay = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* bx = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* by = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* coorx = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* coory = (float*) malloc((ngridx + ngridy) * sizeof(float));
float* dist = (float*) malloc((ngridx + ngridy) * sizeof(float));
int* indi = (int*) malloc((ngridx + ngridy) * sizeof(int));
float* simdata = (float*) malloc((dy * dt * dx) * sizeof(float));
assert(coordx != NULL && coordy != NULL && ax != NULL && ay != NULL && by != NULL &&
bx != NULL && coorx != NULL && coory != NULL && dist != NULL && indi != NULL &&
simdata != NULL);
int s, p, d, i, n;
int quadrant;
float theta_p, sin_p, cos_p;
float mov, xi, yi;
int asize, bsize, csize;
float upd;
int ind_data, ind_recon;
for(i = 0; i < num_iter; i++)
{
// initialize simdata to zero
memset(simdata, 0, dy * dt * dx * sizeof(float));
preprocessing(ngridx, ngridy, dx, center[0], &mov, gridx,
gridy); // Outputs: mov, gridx, gridy
// For each projection angle
for(p = 0; p < dt; p++)
{
// Calculate the sin and cos values
// of the projection angle and find
// at which quadrant on the cartesian grid.
theta_p = fmodf(theta[p], 2.0f * (float) M_PI);
quadrant = calc_quadrant(theta_p);
sin_p = sinf(theta_p);
cos_p = cosf(theta_p);
// For each detector pixel
for(d = 0; d < dx; d++)
{
// Calculate coordinates
xi = -ngridx - ngridy;
yi = 0.5f * (1 - dx) + d + mov;
calc_coords(ngridx, ngridy, xi, yi, sin_p, cos_p, gridx, gridy, coordx,
coordy);
// Merge the (coordx, gridy) and (gridx, coordy)
trim_coords(ngridx, ngridy, coordx, coordy, gridx, gridy, &asize, ax, ay,
&bsize, bx, by);
// Sort the array of intersection points (ax, ay) and
// (bx, by). The new sorted intersection points are
// stored in (coorx, coory). Total number of points
// are csize.
sort_intersections(quadrant, asize, ax, ay, bsize, bx, by, &csize, coorx,
coory);
// Calculate the distances (dist) between the
// intersection points (coorx, coory). Find the
// indices of the pixels on the reconstruction grid.
calc_dist(ngridx, ngridy, csize, coorx, coory, indi, dist);
// Calculate dist*dist
float sum_dist2 = 0.0f;
for(n = 0; n < csize - 1; n++)
{
sum_dist2 += dist[n] * dist[n];
}
if(sum_dist2 != 0.0f)
{
// For each slice
for(s = 0; s < dy; s++)
{
// Calculate simdata
calc_simdata(s, p, d, ngridx, ngridy, dt, dx, csize, indi, dist,
recon,
simdata); // Output: simdata
// Update
ind_data = d + p * dx + s * dt * dx;
ind_recon = s * ngridx * ngridy;
upd = (data[ind_data] - simdata[ind_data]) / sum_dist2;
for(n = 0; n < csize - 1; n++)
{
recon[indi[n] + ind_recon] += upd * dist[n];
}
}
}
}
}
}
free(gridx);
free(gridy);
free(coordx);
free(coordy);
free(ax);
free(ay);
free(bx);
free(by);
free(coorx);
free(coory);
free(dist);
free(indi);
free(simdata);
}
