/* ******** nrrdAxisInfoPosRange() ** ** given a nrrd, an axis, and two (floating point) index space positions, ** return the range of positions implied the axis's min, max, and center ** The opposite of nrrdAxisIdxRange() */ void nrrdAxisInfoPosRange(double *loP, double *hiP, const Nrrd *nrrd, unsigned int ax, double loIdx, double hiIdx) { int center, flip = 0; size_t size; double min, max, tmp; if (!( loP && hiP && nrrd && ax <= nrrd->dim-1 )) { *loP = *hiP = AIR_NAN; return; } center = _nrrdCenter(nrrd->axis[ax].center); min = nrrd->axis[ax].min; max = nrrd->axis[ax].max; size = nrrd->axis[ax].size; if (loIdx > hiIdx) { flip = 1; tmp = loIdx; loIdx = hiIdx; hiIdx = tmp; } if (nrrdCenterCell == center) { *loP = AIR_AFFINE(0, loIdx, size, min, max); *hiP = AIR_AFFINE(0, hiIdx+1, size, min, max); } else { *loP = AIR_AFFINE(0, loIdx, size-1, min, max); *hiP = AIR_AFFINE(0, hiIdx, size-1, min, max); } if (flip) { tmp = *loP; *loP = *hiP; *hiP = tmp; } return; }
void nrrdAxisInfoSpacingSet(Nrrd *nrrd, unsigned int ax) { int sign; double min, max, tmp; if (!( nrrd && ax <= nrrd->dim-1 )) { return; } min = nrrd->axis[ax].min; max = nrrd->axis[ax].max; if (!( AIR_EXISTS(min) && AIR_EXISTS(max) )) { /* there's no actual basis on which to set the spacing information, but we have to set it something, so here goes .. */ nrrd->axis[ax].spacing = nrrdDefaultSpacing; return; } if (min > max) { tmp = min; min = max; max = tmp; sign = -1; } else { sign = 1; } /* the skinny */ nrrd->axis[ax].spacing = NRRD_SPACING(_nrrdCenter(nrrd->axis[ax].center), min, max, nrrd->axis[ax].size); nrrd->axis[ax].spacing *= sign; return; }
/* ** _nrrdResampleCheckInfo() ** ** checks validity of given NrrdResampleInfo *info: ** - all required parameters exist ** - both min[d] and max[d] for all axes d */ int _nrrdResampleCheckInfo(const Nrrd *nin, const NrrdResampleInfo *info) { char me[] = "_nrrdResampleCheckInfo", err[BIFF_STRLEN]; const NrrdKernel *k; int center, p, np; unsigned int ai, minsmp; if (nrrdTypeBlock == nin->type || nrrdTypeBlock == info->type) { sprintf(err, "%s: can't resample to or from type %s", me, airEnumStr(nrrdType, nrrdTypeBlock)); biffAdd(NRRD, err); return 1; } if (nrrdBoundaryUnknown == info->boundary) { sprintf(err, "%s: didn't set boundary behavior\n", me); biffAdd(NRRD, err); return 1; } if (nrrdBoundaryPad == info->boundary && !AIR_EXISTS(info->padValue)) { sprintf(err, "%s: asked for boundary padding, but no pad value set\n", me); biffAdd(NRRD, err); return 1; } for (ai=0; ai<nin->dim; ai++) { k = info->kernel[ai]; /* we only care about the axes being resampled */ if (!k) continue; if (!(info->samples[ai] > 0)) { sprintf(err, "%s: axis %d # samples (" _AIR_SIZE_T_CNV ") invalid", me, ai, info->samples[ai]); biffAdd(NRRD, err); return 1; } if (!( AIR_EXISTS(nin->axis[ai].min) && AIR_EXISTS(nin->axis[ai].max) )) { sprintf(err, "%s: input nrrd's axis %d min,max have not both been set", me, ai); biffAdd(NRRD, err); return 1; } if (!( AIR_EXISTS(info->min[ai]) && AIR_EXISTS(info->max[ai]) )) { sprintf(err, "%s: info's axis %d min,max not both set", me, ai); biffAdd(NRRD, err); return 1; } np = k->numParm; for (p=0; p<np; p++) { if (!AIR_EXISTS(info->parm[ai][p])) { sprintf(err, "%s: didn't set parameter %d (of %d) for axis %d\n", me, p, np, ai); biffAdd(NRRD, err); return 1; } } center = _nrrdCenter(nin->axis[ai].center); minsmp = nrrdCenterCell == center ? 1 : 2; if (!( nin->axis[ai].size >= minsmp && info->samples[ai] >= minsmp )) { sprintf(err, "%s: axis %d # input samples (" _AIR_SIZE_T_CNV ") or output samples (" _AIR_SIZE_T_CNV ") " " invalid for %s centering", me, ai, nin->axis[ai].size, info->samples[ai], airEnumStr(nrrdCenter, center)); biffAdd(NRRD, err); return 1; } } return 0; }
int nrrdSimpleResample(Nrrd *nout, Nrrd *nin, const NrrdKernel *kernel, const double *parm, const size_t *samples, const double *scalings) { char me[]="nrrdSimpleResample", err[BIFF_STRLEN]; NrrdResampleInfo *info; int p, np, center; unsigned ai; if (!(nout && nin && kernel && (samples || scalings))) { sprintf(err, "%s: not NULL pointer", me); biffAdd(NRRD, err); return 1; } if (!(info = nrrdResampleInfoNew())) { sprintf(err, "%s: can't allocate resample info struct", me); biffAdd(NRRD, err); return 1; } np = kernel->numParm; for (ai=0; ai<nin->dim; ai++) { info->kernel[ai] = kernel; if (samples) { info->samples[ai] = samples[ai]; } else { center = _nrrdCenter(nin->axis[ai].center); if (nrrdCenterCell == center) { info->samples[ai] = (size_t)(nin->axis[ai].size*scalings[ai]); } else { info->samples[ai] = (size_t)((nin->axis[ai].size - 1) *scalings[ai]) + 1; } } for (p=0; p<np; p++) info->parm[ai][p] = parm[p]; /* set the min/max for this axis if not already set to something */ if (!( AIR_EXISTS(nin->axis[ai].min) && AIR_EXISTS(nin->axis[ai].max) )) nrrdAxisInfoMinMaxSet(nin, ai, nrrdDefaultCenter); info->min[ai] = nin->axis[ai].min; info->max[ai] = nin->axis[ai].max; } /* we go with the defaults (enstated by _nrrdResampleInfoInit()) for all the remaining fields */ if (nrrdSpatialResample(nout, nin, info)) { sprintf(err, "%s:", me); biffAdd(NRRD, err); return 1; } info = nrrdResampleInfoNix(info); return 0; }
/* ******** nrrdAxisInfoIdx() ** ** given a nrrd, an axis, and a (floating point) world space position, ** return the index implied the axis's min, max, and center. ** Does the opposite of nrrdAxisPos(). ** ** does not use biff */ double nrrdAxisInfoIdx(const Nrrd *nrrd, unsigned int ax, double pos) { int center; size_t size; double min, max; if (!( nrrd && ax <= nrrd->dim-1 )) { return AIR_NAN; } center = _nrrdCenter(nrrd->axis[ax].center); min = nrrd->axis[ax].min; max = nrrd->axis[ax].max; size = nrrd->axis[ax].size; return NRRD_IDX(center, min, max, size, pos); }
/* ******** nrrdSpatialResample() ** ** general-purpose array-resampler: resamples a nrrd of any type ** (except block) and any dimension along any or all of its axes, with ** any combination of up- or down-sampling along the axes, with any ** kernel (specified by callback), with potentially a different kernel ** for each axis. Whether or not to resample along axis d is ** controlled by the non-NULL-ity of info->kernel[ai]. Where to sample ** on the axis is controlled by info->min[ai] and info->max[ai]; these ** specify a range of "positions" aka "world space" positions, as ** determined by the per-axis min and max of the input nrrd, which must ** be set for every resampled axis. ** ** we cyclically permute those axes being resampled, and never touch ** the position (in axis ordering) of axes along which we are not ** resampling. This strategy is certainly not the most intelligent ** one possible, but it does mean that the axis along which we're ** currently resampling-- the one along which we'll have to look at ** multiple adjecent samples-- is that resampling axis which is ** currently most contiguous in memory. It may make sense to precede ** the resampling with an axis permutation which bubbles all the ** resampled axes to the front (most contiguous) end of the axis list, ** and then puts them back in place afterwards, depending on the cost ** of such axis permutation overhead. */ int nrrdSpatialResample(Nrrd *nout, const Nrrd *nin, const NrrdResampleInfo *info) { char me[]="nrrdSpatialResample", func[]="resample", err[BIFF_STRLEN]; nrrdResample_t *array[NRRD_DIM_MAX], /* intermediate copies of the input data undergoing resampling; we don't need a full- fledged nrrd for these. Only about two of these arrays will be allocated at a time; intermediate results will be free()d when not needed */ *_inVec, /* current input vector being resampled; not necessarily contiguous in memory (if strideIn != 1) */ *inVec, /* buffer for input vector; contiguous */ *_outVec; /* output vector in context of volume; never contiguous */ double tmpF; double ratio, /* factor by which or up or downsampled */ ratios[NRRD_DIM_MAX]; /* record of "ratio" for all resampled axes, used to compute new spacing in output */ Nrrd *floatNin; /* if the input nrrd type is not nrrdResample_t, then we convert it and keep it here */ unsigned int ai, pi, /* current pass */ topLax, permute[NRRD_DIM_MAX], /* how to permute axes of last pass to get axes for current pass */ ax[NRRD_DIM_MAX+1][NRRD_DIM_MAX], /* axis ordering on each pass */ passes; /* # of passes needed to resample all axes */ int i, s, e, topRax, /* the lowest index of an axis which is resampled. If all axes are being resampled, then this is 0. If for some reason the "x" axis (fastest stride) is not being resampled, but "y" is, then topRax is 1 */ botRax, /* index of highest axis being resampled */ typeIn, typeOut; /* types of input and output of resampling */ size_t sz[NRRD_DIM_MAX+1][NRRD_DIM_MAX]; /* how many samples along each axis, changing on each pass */ /* all these variables have to do with the spacing of elements in memory for the current pass of resampling, and they (except strideIn) are re-set at the beginning of each pass */ nrrdResample_t *weight; /* sample weights */ unsigned int ci[NRRD_DIM_MAX+1], co[NRRD_DIM_MAX+1]; int sizeIn, sizeOut, /* lengths of input and output vectors */ dotLen, /* # input samples to dot with weights to get one output sample */ doRound, /* actually do rounding on output: we DO NOT round when info->round but the output type is not integral */ *index; /* dotLen*sizeOut 2D array of input indices */ size_t I, /* swiss-army int */ strideIn, /* the stride between samples in the input "scanline" being resampled */ strideOut, /* stride between samples in output "scanline" from resampling */ L, LI, LO, numLines, /* top secret */ numOut; /* # of _samples_, total, in output volume; this is for allocating the output */ airArray *mop; /* for cleaning up */ if (!(nout && nin && info)) { sprintf(err, "%s: got NULL pointer", me); biffAdd(NRRD, err); return 1; } if (nrrdBoundaryUnknown == info->boundary) { sprintf(err, "%s: need to specify a boundary behavior", me); biffAdd(NRRD, err); return 1; } typeIn = nin->type; typeOut = nrrdTypeDefault == info->type ? typeIn : info->type; if (_nrrdResampleCheckInfo(nin, info)) { sprintf(err, "%s: problem with arguments", me); biffAdd(NRRD, err); return 1; } _nrrdResampleComputePermute(permute, ax, sz, &topRax, &botRax, &passes, nin, info); topLax = topRax ? 0 : 1; /* not sure where else to put this: (want to put it before 0 == passes branch) We have to assume some centering when doing resampling, and it would be stupid to not record it in the outgoing nrrd, since the value of nrrdDefaultCenter could always change. */ for (ai=0; ai<nin->dim; ai++) { if (info->kernel[ai]) { nout->axis[ai].center = _nrrdCenter(nin->axis[ai].center); } } if (0 == passes) { /* actually, no resampling was desired. Copy input to output, but with the clamping that we normally do at the end of resampling */ nrrdAxisInfoGet_nva(nin, nrrdAxisInfoSize, sz[0]); if (nrrdMaybeAlloc_nva(nout, typeOut, nin->dim, sz[0])) { sprintf(err, "%s: couldn't allocate output", me); biffAdd(NRRD, err); return 1; } numOut = nrrdElementNumber(nout); for (I=0; I<numOut; I++) { tmpF = nrrdDLookup[nin->type](nin->data, I); tmpF = nrrdDClamp[typeOut](tmpF); nrrdDInsert[typeOut](nout->data, I, tmpF); } nrrdAxisInfoCopy(nout, nin, NULL, NRRD_AXIS_INFO_NONE); /* HEY: need to create textual representation of resampling parameters */ if (nrrdContentSet_va(nout, func, nin, "")) { sprintf(err, "%s:", me); biffAdd(NRRD, err); return 1; } if (nrrdBasicInfoCopy(nout, nin, NRRD_BASIC_INFO_DATA_BIT | NRRD_BASIC_INFO_TYPE_BIT | NRRD_BASIC_INFO_BLOCKSIZE_BIT | NRRD_BASIC_INFO_DIMENSION_BIT | NRRD_BASIC_INFO_CONTENT_BIT | NRRD_BASIC_INFO_COMMENTS_BIT | (nrrdStateKeyValuePairsPropagate ? 0 : NRRD_BASIC_INFO_KEYVALUEPAIRS_BIT))) { sprintf(err, "%s:", me); biffAdd(NRRD, err); return 1; } return 0; } mop = airMopNew(); /* convert input nrrd to nrrdResample_t if necessary */ if (nrrdResample_nrrdType != typeIn) { if (nrrdConvert(floatNin = nrrdNew(), nin, nrrdResample_nrrdType)) { sprintf(err, "%s: couldn't create float copy of input", me); biffAdd(NRRD, err); airMopError(mop); return 1; } array[0] = (nrrdResample_t*)floatNin->data; airMopAdd(mop, floatNin, (airMopper)nrrdNuke, airMopAlways); } else { floatNin = NULL; array[0] = (nrrdResample_t*)nin->data; } /* compute strideIn; this is actually the same for every pass because (strictly speaking) in every pass we are resampling the same axis, and axes with lower indices are constant length */ strideIn = 1; for (ai=0; ai<(unsigned int)topRax; ai++) { /* HEY scrutinize casts */ strideIn *= nin->axis[ai].size; } /* printf("%s: strideIn = " _AIR_SIZE_T_CNV "\n", me, strideIn); */ /* go! */ for (pi=0; pi<passes; pi++) { /* printf("%s: --- pass %d --- \n", me, pi); */ numLines = strideOut = 1; for (ai=0; ai<nin->dim; ai++) { if (ai < (unsigned int)botRax) { /* HEY scrutinize cast */ strideOut *= sz[pi+1][ai]; } if (ai != (unsigned int)topRax) { /* HEY scrutinize cast */ numLines *= sz[pi][ai]; } } sizeIn = sz[pi][topRax]; sizeOut = sz[pi+1][botRax]; numOut = numLines*sizeOut; /* for the rest of the loop body, d is the original "dimension" for the axis being resampled */ ai = ax[pi][topRax]; /* printf("%s(%d): numOut = " _AIR_SIZE_T_CNV "\n", me, pi, numOut); printf("%s(%d): numLines = " _AIR_SIZE_T_CNV "\n", me, pi, numLines); printf("%s(%d): stride: In=%d, Out=%d\n", me, pi, (int)strideIn, (int)strideOut); printf("%s(%d): sizeIn = %d\n", me, pi, sizeIn); printf("%s(%d): sizeOut = %d\n", me, pi, sizeOut); */ /* we can free the input to the previous pass (if its not the given data) */ if (pi > 0) { if (pi == 1) { if (array[0] != nin->data) { airMopSub(mop, floatNin, (airMopper)nrrdNuke); floatNin = nrrdNuke(floatNin); array[0] = NULL; /* printf("%s: pi %d: freeing array[0]\n", me, pi); */ } } else { airMopSub(mop, array[pi-1], airFree); array[pi-1] = (nrrdResample_t*)airFree(array[pi-1]); /* printf("%s: pi %d: freeing array[%d]\n", me, pi, pi-1); */ } } /* allocate output volume */ array[pi+1] = (nrrdResample_t*)calloc(numOut, sizeof(nrrdResample_t)); if (!array[pi+1]) { sprintf(err, "%s: couldn't create array of " _AIR_SIZE_T_CNV " nrrdResample_t's for output of pass %d", me, numOut, pi); biffAdd(NRRD, err); airMopError(mop); return 1; } airMopAdd(mop, array[pi+1], airFree, airMopAlways); /* printf("%s: allocated array[%d]\n", me, pi+1); */ /* allocate contiguous input scanline buffer, we alloc one more than needed to provide a place for the pad value. That is, in fact, the over-riding reason to copy a scanline to a local array: so that there is a simple consistent (non-branchy) way to incorporate the pad values */ inVec = (nrrdResample_t *)calloc(sizeIn+1, sizeof(nrrdResample_t)); airMopAdd(mop, inVec, airFree, airMopAlways); inVec[sizeIn] = AIR_CAST(nrrdResample_t, info->padValue); dotLen = _nrrdResampleMakeWeightIndex(&weight, &index, &ratio, nin, info, ai); if (!dotLen) { sprintf(err, "%s: trouble creating weight and index vector arrays", me); biffAdd(NRRD, err); airMopError(mop); return 1; } ratios[ai] = ratio; airMopAdd(mop, weight, airFree, airMopAlways); airMopAdd(mop, index, airFree, airMopAlways); /* the skinny: resample all the scanlines */ _inVec = array[pi]; _outVec = array[pi+1]; memset(ci, 0, (NRRD_DIM_MAX+1)*sizeof(int)); memset(co, 0, (NRRD_DIM_MAX+1)*sizeof(int)); for (L=0; L<numLines; L++) { /* calculate the index to get to input and output scanlines, according the coordinates of the start of the scanline */ NRRD_INDEX_GEN(LI, ci, sz[pi], nin->dim); NRRD_INDEX_GEN(LO, co, sz[pi+1], nin->dim); _inVec = array[pi] + LI; _outVec = array[pi+1] + LO; /* read input scanline into contiguous array */ for (i=0; i<sizeIn; i++) { inVec[i] = _inVec[i*strideIn]; } /* do the weighting */ for (i=0; i<sizeOut; i++) { tmpF = 0.0; /* fprintf(stderr, "%s: i = %d (tmpF=0)\n", me, (int)i); */ for (s=0; s<dotLen; s++) { tmpF += inVec[index[s + dotLen*i]]*weight[s + dotLen*i]; /* fprintf(stderr, " tmpF += %g*%g == %g\n", inVec[index[s + dotLen*i]], weight[s + dotLen*i], tmpF); */ } _outVec[i*strideOut] = tmpF; /* fprintf(stderr, "--> out[%d] = %g\n", i*strideOut, _outVec[i*strideOut]); */ } /* update the coordinates for the scanline starts. We don't use the usual NRRD_COORD macros because we're subject to the unusual constraint that ci[topRax] and co[permute[topRax]] must stay exactly zero */ e = topLax; ci[e]++; co[permute[e]]++; while (L < numLines-1 && ci[e] == sz[pi][e]) { ci[e] = co[permute[e]] = 0; e++; e += e == topRax; ci[e]++; co[permute[e]]++; } } /* pass-specific clean up */ airMopSub(mop, weight, airFree); airMopSub(mop, index, airFree); airMopSub(mop, inVec, airFree); weight = (nrrdResample_t*)airFree(weight); index = (int*)airFree(index); inVec = (nrrdResample_t*)airFree(inVec); } /* clean up second-to-last array and scanline buffers */ if (passes > 1) { airMopSub(mop, array[passes-1], airFree); array[passes-1] = (nrrdResample_t*)airFree(array[passes-1]); /* printf("%s: now freeing array[%d]\n", me, passes-1); */ } else if (array[passes-1] != nin->data) { airMopSub(mop, floatNin, (airMopper)nrrdNuke); floatNin = nrrdNuke(floatNin); } array[passes-1] = NULL; /* create output nrrd and set axis info */ if (nrrdMaybeAlloc_nva(nout, typeOut, nin->dim, sz[passes])) { sprintf(err, "%s: couldn't allocate final output nrrd", me); biffAdd(NRRD, err); airMopError(mop); return 1; } airMopAdd(mop, nout, (airMopper)nrrdNuke, airMopOnError); nrrdAxisInfoCopy(nout, nin, NULL, (NRRD_AXIS_INFO_SIZE_BIT | NRRD_AXIS_INFO_MIN_BIT | NRRD_AXIS_INFO_MAX_BIT | NRRD_AXIS_INFO_SPACING_BIT | NRRD_AXIS_INFO_SPACEDIRECTION_BIT /* see below */ | NRRD_AXIS_INFO_THICKNESS_BIT | NRRD_AXIS_INFO_KIND_BIT)); for (ai=0; ai<nin->dim; ai++) { if (info->kernel[ai]) { /* we do resample this axis */ nout->axis[ai].spacing = nin->axis[ai].spacing/ratios[ai]; /* no way to usefully update thickness: we could be doing blurring but maintaining the number of samples: thickness increases, or we could be downsampling, in which the relationship between the sampled and the skipped regions of space becomes complicated: no single scalar can represent it, or we could be upsampling, in which the notion of "skip" could be rendered meaningless */ nout->axis[ai].thickness = AIR_NAN; nout->axis[ai].min = info->min[ai]; nout->axis[ai].max = info->max[ai]; /* HEY: this is currently a bug: all this code was written long before there were space directions, so min/max are always set, regardless of whethere there are incoming space directions which then disallows output space directions on the same axes _nrrdSpaceVecScale(nout->axis[ai].spaceDirection, 1.0/ratios[ai], nin->axis[ai].spaceDirection); */ nout->axis[ai].kind = _nrrdKindAltered(nin->axis[ai].kind, AIR_TRUE); } else { /* this axis remains untouched */ nout->axis[ai].min = nin->axis[ai].min; nout->axis[ai].max = nin->axis[ai].max; nout->axis[ai].spacing = nin->axis[ai].spacing; nout->axis[ai].thickness = nin->axis[ai].thickness; nout->axis[ai].kind = nin->axis[ai].kind; } } /* HEY: need to create textual representation of resampling parameters */ if (nrrdContentSet_va(nout, func, nin, "")) { sprintf(err, "%s:", me); biffAdd(NRRD, err); return 1; } /* copy the resampling final result into the output nrrd, maybe rounding as we go to make sure that 254.9999 is saved as 255 in uchar output, and maybe clamping as we go to insure that integral results don't have unexpected wrap-around. */ if (info->round) { if (nrrdTypeInt == typeOut || nrrdTypeUInt == typeOut || nrrdTypeLLong == typeOut || nrrdTypeULLong == typeOut) { fprintf(stderr, "%s: WARNING: possible erroneous output with " "rounding of %s output type due to int-based implementation " "of rounding\n", me, airEnumStr(nrrdType, typeOut)); } doRound = nrrdTypeIsIntegral[typeOut]; } else { doRound = AIR_FALSE; } numOut = nrrdElementNumber(nout); for (I=0; I<numOut; I++) { tmpF = array[passes][I]; if (doRound) { tmpF = AIR_CAST(nrrdResample_t, AIR_ROUNDUP(tmpF)); } if (info->clamp) { tmpF = nrrdDClamp[typeOut](tmpF); } nrrdDInsert[typeOut](nout->data, I, tmpF); } if (nrrdBasicInfoCopy(nout, nin, NRRD_BASIC_INFO_DATA_BIT | NRRD_BASIC_INFO_TYPE_BIT | NRRD_BASIC_INFO_BLOCKSIZE_BIT | NRRD_BASIC_INFO_DIMENSION_BIT | NRRD_BASIC_INFO_CONTENT_BIT | NRRD_BASIC_INFO_COMMENTS_BIT | (nrrdStateKeyValuePairsPropagate ? 0 : NRRD_BASIC_INFO_KEYVALUEPAIRS_BIT))) { sprintf(err, "%s:", me); biffAdd(NRRD, err); return 1; } /* enough already */ airMopOkay(mop); return 0; }
/* ** _nrrdResampleMakeWeightIndex() ** ** _allocate_ and fill the arrays of indices and weights that are ** needed to process all the scanlines along a given axis; also ** be so kind as to set the sampling ratio (<1: downsampling, ** new sample spacing larger, >1: upsampling, new sample spacing smaller) ** ** returns "dotLen", the number of input samples which are required ** for resampling this axis, or 0 if there was an error. Uses biff. */ int _nrrdResampleMakeWeightIndex(nrrdResample_t **weightP, int **indexP, double *ratioP, const Nrrd *nin, const NrrdResampleInfo *info, unsigned int ai) { char me[]="_nrrdResampleMakeWeightIndex", err[BIFF_STRLEN]; int sizeIn, sizeOut, center, dotLen, halfLen, *index, base, idx; nrrdResample_t minIn, maxIn, minOut, maxOut, spcIn, spcOut, ratio, support, integral, pos, idxD, wght; nrrdResample_t *weight; double parm[NRRD_KERNEL_PARMS_NUM]; int e, i; if (!(info->kernel[ai])) { sprintf(err, "%s: don't see a kernel for dimension %d", me, ai); biffAdd(NRRD, err); *weightP = NULL; *indexP = NULL; return 0; } center = _nrrdCenter(nin->axis[ai].center); sizeIn = nin->axis[ai].size; sizeOut = info->samples[ai]; minIn = AIR_CAST(nrrdResample_t, nin->axis[ai].min); maxIn = AIR_CAST(nrrdResample_t, nin->axis[ai].max); minOut = AIR_CAST(nrrdResample_t, info->min[ai]); maxOut = AIR_CAST(nrrdResample_t, info->max[ai]); spcIn = NRRD_SPACING(center, minIn, maxIn, sizeIn); spcOut = NRRD_SPACING(center, minOut, maxOut, sizeOut); *ratioP = ratio = spcIn/spcOut; support = AIR_CAST(nrrdResample_t, info->kernel[ai]->support(info->parm[ai])); integral = AIR_CAST(nrrdResample_t, info->kernel[ai]->integral(info->parm[ai])); /* fprintf(stderr, "!%s(%d): size{In,Out} = %d, %d, support = %f; ratio = %f\n", me, d, sizeIn, sizeOut, support, ratio); */ if (ratio > 1) { /* if upsampling, we need only as many samples as needed for interpolation with the given kernel */ dotLen = (int)(2*ceil(support)); } else { /* if downsampling, we need to use all the samples covered by the stretched out version of the kernel */ if (info->cheap) { dotLen = (int)(2*ceil(support)); } else { dotLen = (int)(2*ceil(support/ratio)); } } /* fprintf(stderr, "!%s(%d): dotLen = %d\n", me, d, dotLen); */ weight = (nrrdResample_t*)calloc(sizeOut*dotLen, sizeof(nrrdResample_t)); index = (int*)calloc(sizeOut*dotLen, sizeof(int)); if (!(weight && index)) { sprintf(err, "%s: can't allocate weight and index arrays", me); biffAdd(NRRD, err); *weightP = NULL; *indexP = NULL; return 0; } /* calculate sample locations and do first pass on indices */ halfLen = dotLen/2; for (i=0; i<sizeOut; i++) { pos = AIR_CAST(nrrdResample_t, NRRD_POS(center, minOut, maxOut, sizeOut, i)); idxD = AIR_CAST(nrrdResample_t, NRRD_IDX(center, minIn, maxIn, sizeIn, pos)); base = (int)floor(idxD) - halfLen + 1; for (e=0; e<dotLen; e++) { index[e + dotLen*i] = base + e; weight[e + dotLen*i] = idxD - index[e + dotLen*i]; } /* ******** if (!i) { fprintf(stderr, "%s: sample locations:\n", me); } fprintf(stderr, "%s: %d (sample locations)\n ", me, i); for (e=0; e<dotLen; e++) { fprintf(stderr, "%d/%g ", index[e + dotLen*i], weight[e + dotLen*i]); } fprintf(stderr, "\n"); ******** */ } /* nrrdBoundaryPad, 1: fill with some user-specified value nrrdBoundaryBleed, 2: copy the last/first value out as needed nrrdBoundaryWrap, 3: wrap-around nrrdBoundaryWeight, 4: normalize the weighting on the existing samples; ONLY sensible for a strictly positive kernel which integrates to unity (as in blurring) */ /* figure out what to do with the out-of-range indices */ for (i=0; i<dotLen*sizeOut; i++) { idx = index[i]; if (!AIR_IN_CL(0, idx, sizeIn-1)) { switch(info->boundary) { case nrrdBoundaryPad: case nrrdBoundaryWeight: /* this will be further handled later */ idx = sizeIn; break; case nrrdBoundaryBleed: idx = AIR_CLAMP(0, idx, sizeIn-1); break; case nrrdBoundaryWrap: idx = AIR_MOD(idx, sizeIn); break; default: sprintf(err, "%s: boundary behavior %d unknown/unimplemented", me, info->boundary); biffAdd(NRRD, err); *weightP = NULL; *indexP = NULL; return 0; } index[i] = idx; } } /* run the sample locations through the chosen kernel. We play a sneaky trick on the kernel parameter 0 in case of downsampling to create the blurring of the old index space, but only if !cheap */ memcpy(parm, info->parm[ai], NRRD_KERNEL_PARMS_NUM*sizeof(double)); if (ratio < 1 && !(info->cheap)) { parm[0] /= ratio; } info->kernel[ai]->EVALN(weight, weight, dotLen*sizeOut, parm); /* ******** for (i=0; i<sizeOut; i++) { fprintf(stderr, "%s: %d (sample weights)\n ", me, i); for (e=0; e<dotLen; e++) { fprintf(stderr, "%d/%g ", index[e + dotLen*i], weight[e + dotLen*i]); } fprintf(stderr, "\n"); } ******** */ if (nrrdBoundaryWeight == info->boundary) { if (integral) { /* above, we set to sizeIn all the indices that were out of range. We now use that to determine the sum of the weights for the indices that were in-range */ for (i=0; i<sizeOut; i++) { wght = 0; for (e=0; e<dotLen; e++) { if (sizeIn != index[e + dotLen*i]) { wght += weight[e + dotLen*i]; } } for (e=0; e<dotLen; e++) { idx = index[e + dotLen*i]; if (sizeIn != idx) { weight[e + dotLen*i] *= integral/wght; } else { weight[e + dotLen*i] = 0; } } } } } else { /* try to remove ripple/grating on downsampling */ /* if (ratio < 1 && info->renormalize && integral) { */ if (info->renormalize && integral) { for (i=0; i<sizeOut; i++) { wght = 0; for (e=0; e<dotLen; e++) { wght += weight[e + dotLen*i]; } if (wght) { for (e=0; e<dotLen; e++) { /* this used to normalize the weights so that they summed to integral ("*= integral/wght"), which meant that if you use a very truncated Gaussian, then your over-all image brightness goes down. This seems very contrary to the whole point of renormalization. */ weight[e + dotLen*i] *= AIR_CAST(nrrdResample_t, 1.0/wght); } } } } } /* ******** fprintf(stderr, "%s: sample weights:\n", me); for (i=0; i<sizeOut; i++) { fprintf(stderr, "%s: %d\n ", me, i); wght = 0; for (e=0; e<dotLen; e++) { fprintf(stderr, "%d/%g ", index[e + dotLen*i], weight[e + dotLen*i]); wght += weight[e + dotLen*i]; } fprintf(stderr, " (sum = %g)\n", wght); } ******** */ *weightP = weight; *indexP = index; /* fprintf(stderr, "!%s: dotLen = %d\n", me, dotLen); */ return dotLen; }