int dsigma(float *image,
int nx,
int ny,
int sp,
float *sigma)
{
float tot;
int i,j,dx,dy, ndiff;
if(nx==1 && ny==1) {
(*sigma)=0.;
return(0);
}
dx=50;
if(dx>nx/4) dx=nx/4;
if(dx<=0) dx=1;
dy=50;
if(dy>ny/4) dy=ny/4;
if(dy<=0) dy=1;
diff=(float *) malloc(2*nx*ny*sizeof(float));
ndiff=0;
for(j=0;j<ny;j+=dy) {
for(i=0;i<nx;i+=dx) {
if(i<nx-sp) {
diff[ndiff]=fabs(image[i+j*nx]-image[i+sp+j*nx]);
ndiff++;
}
if(j<ny-sp) {
diff[ndiff]=fabs(image[i+j*nx]-image[i+(j+sp)*nx]);
ndiff++;
}
}
}
if(ndiff<=1) {
(*sigma)=0.;
return(0);
}
if(ndiff<=10) {
tot=0.;
for(i=0;i<ndiff;i++)
tot+=diff[i]*diff[i];
(*sigma)=sqrt(tot/(float) ndiff);
return(0);
}
(*sigma)=(dselip((int) floor(ndiff*0.68),ndiff,diff))/sqrt(2.);
FREEVEC(diff);
return(1);
} /* end dsigma */
int dmedsmooth(const float *image,
const uint8_t *masked,
int nx,
int ny,
int halfbox,
float *smooth)
{
int i, j, ip, jp, ist, jst, nb, ind, jnd, sp;
int xoff, yoff, nm, nxgrid, nygrid;
int ypsize, ymsize, xpsize, xmsize;
float dx, dy, xkernel, ykernel;
float *arr = NULL;
int *xgrid = NULL;
int *ygrid = NULL;
float *grid = NULL;
int *xlo = NULL;
int *xhi = NULL;
int *ylo = NULL;
int *yhi = NULL;
/* get grids */
sp = halfbox;
nxgrid = MAX(1, nx / sp) + 2;
//printf("nxgrid %i\n", nxgrid);
// "xgrid" are the centers.
// "xlo" are the (inclusive) lower-bounds
// "xhi" are the (inclusive) upper-bounds
// the grid cells may overlap.
xgrid = (int *) malloc((size_t)nxgrid * sizeof(int));
xlo = (int *) malloc((size_t)nxgrid * sizeof(int));
xhi = (int *) malloc((size_t)nxgrid * sizeof(int));
xoff = (nx - 1 - (nxgrid - 3) * sp) / 2;
for (i = 1;i < nxgrid - 1;i++)
xgrid[i] = (i - 1) * sp + xoff;
xgrid[0] = xgrid[1] - sp;
xgrid[nxgrid - 1] = xgrid[nxgrid - 2] + sp;
for (i = 0;i < nxgrid;i++) {
xlo[i] = MAX(xgrid[i] - sp, 0);
xhi[i] = MIN(xgrid[i] + sp, nx-1);
//printf("xlo[%i],xhi[%i] = %i,%i\n", i, i, xlo[i], xhi[i]);
}
nygrid = MAX(1, ny / sp) + 2;
//printf("nygrid %i\n", nygrid);
ylo = (int *) malloc(nygrid * sizeof(int));
yhi = (int *) malloc(nygrid * sizeof(int));
ygrid = (int *) malloc(nygrid * sizeof(int));
yoff = (ny - 1 - (nygrid - 3) * sp) / 2;
for (i = 1;i < nygrid - 1;i++)
ygrid[i] = (i - 1) * sp + yoff;
ygrid[0] = ygrid[1] - sp;
ygrid[nygrid - 1] = ygrid[nygrid - 2] + sp;
for (i = 0;i < nygrid;i++) {
ylo[i] = MAX(ygrid[i] - sp, 0);
yhi[i] = MIN(ygrid[i] + sp, ny-1);
//printf("ylo[%i],yhi[%i] = %i,%i\n", i, i, ylo[i], yhi[i]);
}
// the median-filtered image (subsampled on a grid).
grid = (float *) malloc((size_t)(nxgrid * nygrid) * sizeof(float));
arr = (float *) malloc((size_t)((sp * 2 + 5) * (sp * 2 + 5)) * sizeof(float));
for (j=0; j<nygrid; j++) {
for (i=0; i<nxgrid; i++) {
nb = 0;
for (jp=ylo[j]; jp<=yhi[j]; jp++) {
const float* imageptr = image + xlo[i] + jp * nx;
float f;
if (masked) {
const uint8_t* maskptr = masked + xlo[i] + jp * nx;
for (ip=xlo[i]; ip<=xhi[i]; ip++, imageptr++, maskptr++) {
if (*maskptr)
continue;
f = (*imageptr);
if (!isfinite(f))
continue;
arr[nb] = f;
nb++;
}
} else {
for (ip=xlo[i]; ip<=xhi[i]; ip++, imageptr++) {
f = (*imageptr);
if (!isfinite(f))
continue;
arr[nb] = f;
nb++;
}
}
}
if (nb > 1) {
nm = nb / 2;
grid[i + j*nxgrid] = dselip(nm, nb, arr);
} else {
grid[i + j*nxgrid] = image[(long)xlo[i] + ((long)ylo[j]) * nx];
}
}
}
FREEVEC(xlo);
FREEVEC(ylo);
FREEVEC(xhi);
FREEVEC(yhi);
FREEVEC(arr);
for (j = 0;j < ny;j++)
for (i = 0;i < nx;i++)
smooth[i + j*nx] = 0.;
for (j = 0;j < nygrid;j++) {
jst = (long) ( (float) ygrid[j] - sp * 1.5);
jnd = (long) ( (float) ygrid[j] + sp * 1.5);
if (jst < 0)
jst = 0;
if (jnd > ny - 1)
jnd = ny - 1;
ypsize = sp;
ymsize = sp;
if (j == 0)
ypsize = ygrid[1] - ygrid[0];
if (j == 1)
ymsize = ygrid[1] - ygrid[0];
if (j == nygrid - 2)
ypsize = ygrid[nygrid - 1] - ygrid[nygrid - 2];
if (j == nygrid - 1)
ymsize = ygrid[nygrid - 1] - ygrid[nygrid - 2];
for (i = 0;i < nxgrid;i++) {
ist = (long) ( (float) xgrid[i] - sp * 1.5);
ind = (long) ( (float) xgrid[i] + sp * 1.5);
if (ist < 0)
ist = 0;
if (ind > nx - 1)
ind = nx - 1;
xpsize = sp;
xmsize = sp;
if (i == 0)
xpsize = xgrid[1] - xgrid[0];
if (i == 1)
xmsize = xgrid[1] - xgrid[0];
if (i == nxgrid - 2)
xpsize = xgrid[nxgrid - 1] - xgrid[nxgrid - 2];
if (i == nxgrid - 1)
xmsize = xgrid[nxgrid - 1] - xgrid[nxgrid - 2];
for (jp = jst;jp <= jnd;jp++) {
// Interpolate with a kernel that is two parabolas spliced
// together: in [-1.5, -0.5] and [0.5, 1.5], 0.5 * (|y|-1.5)^2
// so at +- 0.5 it has value 0.5.
// at +- 1.5 it has value 0.
// in [-0.5, 0.5]: 0.75 - (y^2)
// so at +- 0.5 it has value 0.5
// at 0 it has value 0.75
dy = (float)(jp - ygrid[j]);
if (dy >= 0) {
dy /= (float)ypsize;
} else {
dy /= (float)(-ymsize);
}
if ((dy >= 0.5) && (dy < 1.5))
ykernel = 0.5 * (dy - 1.5) * (dy - 1.5);
else if (dy < 0.5)
ykernel = 0.75 - (dy * dy);
else
// ykernel = 0
continue;
for (ip = ist; ip <= ind; ip++) {
dx = (float)(ip - xgrid[i]);
if (dx >= 0) {
dx /= (float)xpsize;
} else {
dx /= (float)(-xmsize);
}
if ((dx >= 0.5) && (dx < 1.5))
xkernel = 0.5 * (dx - 1.5) * (dx - 1.5);
else if (dx < 0.5)
xkernel = 0.75 - (dx * dx);
else
// xkernel = 0
continue;
smooth[ip + jp*nx] += xkernel * ykernel * grid[i + j * nxgrid];
}
}
}
}
FREEVEC(grid);
FREEVEC(xgrid);
FREEVEC(ygrid);
return 1;
}