| 1 |
greg |
2.3 |
#ifndef lint |
| 2 |
rschregle |
2.5 |
static const char RCSid[] = "$Id: pmapbias.c,v 4.7 2015/11/16 13:32:03 taschreg Exp taschreg $"; |
| 3 |
greg |
2.3 |
#endif |
| 4 |
rschregle |
2.5 |
|
| 5 |
greg |
2.1 |
/* |
| 6 |
|
|
================================================================== |
| 7 |
|
|
Bias compensation for photon density estimates |
| 8 |
|
|
|
| 9 |
|
|
For background see: |
| 10 |
|
|
R. Schregle, "Bias Compensation for Photon Maps", |
| 11 |
|
|
Computer Graphics Forum, v22:n4, pp. 729-742, Dec. 2003. |
| 12 |
|
|
|
| 13 |
rschregle |
2.2 |
Roland Schregle ([email protected]) |
| 14 |
|
|
(c) Fraunhofer Institute for Solar Energy Systems |
| 15 |
greg |
2.1 |
================================================================== |
| 16 |
|
|
|
| 17 |
rschregle |
2.5 |
$Id: pmapbias.c,v 4.7 2015/11/16 13:32:03 taschreg Exp taschreg $ |
| 18 |
greg |
2.1 |
*/ |
| 19 |
|
|
|
| 20 |
|
|
|
| 21 |
|
|
|
| 22 |
|
|
#include "pmapbias.h" |
| 23 |
|
|
#include "pmap.h" |
| 24 |
|
|
#include "pmaprand.h" |
| 25 |
|
|
|
| 26 |
|
|
|
| 27 |
|
|
|
| 28 |
rschregle |
2.5 |
void squeuePartition (PhotonSearchQueueNode* squeue, unsigned lo, |
| 29 |
greg |
2.1 |
unsigned mid, unsigned hi) |
| 30 |
|
|
/* REVERSE Partition squeue such that all photons in |
| 31 |
|
|
squeue-hi+1..squeue-mid are farther than the median at squeue-mid+1, |
| 32 |
|
|
and those in squeue-mid+2..squeue-lo+1 are closer than the median. |
| 33 |
|
|
This means that squeue points to the END of the queue, and the (1-based) |
| 34 |
|
|
indices are offsets relative to it. This convoluted scheme is adopted |
| 35 |
|
|
since the queue is initially a maxheap, so reverse sorting is expected |
| 36 |
|
|
to be faster. */ |
| 37 |
|
|
{ |
| 38 |
rschregle |
2.5 |
unsigned l, h, p; |
| 39 |
|
|
PhotonSearchQueueNode *lp, *hp, *pp, tmp; |
| 40 |
|
|
float pivot; |
| 41 |
greg |
2.1 |
|
| 42 |
|
|
while (hi > lo) { |
| 43 |
|
|
/* Grab pivot node in middle as an educated guess, since our |
| 44 |
|
|
queue is sorta sorted. */ |
| 45 |
|
|
l = lo; |
| 46 |
|
|
h = hi; |
| 47 |
|
|
p = mid; |
| 48 |
|
|
lp = squeue - lo + 1; |
| 49 |
|
|
hp = squeue - hi + 1; |
| 50 |
|
|
pp = squeue - p + 1; |
| 51 |
rschregle |
2.5 |
pivot = pp -> dist2; |
| 52 |
greg |
2.1 |
|
| 53 |
|
|
/* l & h converge, swapping elements out of order with respect to |
| 54 |
|
|
pivot node. */ |
| 55 |
|
|
while (l < h) { |
| 56 |
rschregle |
2.5 |
while (lp -> dist2 <= pivot && l <= h && l < hi) |
| 57 |
greg |
2.1 |
++l, --lp; |
| 58 |
rschregle |
2.5 |
|
| 59 |
|
|
while (hp -> dist2 >= pivot && h >= l && h > lo) |
| 60 |
greg |
2.1 |
--h, ++hp; |
| 61 |
|
|
|
| 62 |
|
|
if (l < h) { |
| 63 |
|
|
/* Swap */ |
| 64 |
rschregle |
2.5 |
tmp.idx = lp -> idx; |
| 65 |
|
|
tmp.dist2 = lp -> dist2; |
| 66 |
|
|
lp -> idx = hp -> idx; |
| 67 |
|
|
lp -> dist2 = hp -> dist2; |
| 68 |
|
|
hp -> idx = tmp.idx; |
| 69 |
|
|
hp -> dist2 = tmp.dist2; |
| 70 |
greg |
2.1 |
} |
| 71 |
|
|
} |
| 72 |
|
|
|
| 73 |
|
|
/* Swap convergence and pivot node */ |
| 74 |
|
|
if (p > h) { |
| 75 |
|
|
/* Need this otherwise shit happens! |
| 76 |
rschregle |
2.5 |
Since lp -> dist2 > hp -> dist2, we swap either l or p depending |
| 77 |
greg |
2.1 |
on whether we're above or below p */ |
| 78 |
|
|
h = l; |
| 79 |
|
|
hp = lp; |
| 80 |
|
|
} |
| 81 |
|
|
|
| 82 |
rschregle |
2.5 |
tmp.idx = hp -> idx; |
| 83 |
|
|
tmp.dist2 = hp -> dist2; |
| 84 |
|
|
hp -> idx = pp -> idx; |
| 85 |
|
|
hp -> dist2 = pivot; |
| 86 |
|
|
pp -> idx = tmp.idx; |
| 87 |
|
|
pp -> dist2 = tmp.dist2; |
| 88 |
|
|
|
| 89 |
greg |
2.1 |
if (h >= mid) |
| 90 |
|
|
hi = h - 1; |
| 91 |
rschregle |
2.5 |
|
| 92 |
greg |
2.1 |
if (h <= mid) |
| 93 |
|
|
lo = h + 1; |
| 94 |
|
|
} |
| 95 |
|
|
|
| 96 |
|
|
/* Once lo & hi have converged, we have found the median! */ |
| 97 |
|
|
} |
| 98 |
|
|
|
| 99 |
|
|
|
| 100 |
|
|
|
| 101 |
|
|
void biasComp (PhotonMap* pmap, COLOR irrad) |
| 102 |
|
|
/* Photon density estimate with bias compensation -- czech dis shit out! */ |
| 103 |
|
|
{ |
| 104 |
rschregle |
2.5 |
unsigned i, numLo, numHi, numMid; |
| 105 |
|
|
float r, totalWeight = 0; |
| 106 |
|
|
COLOR fluxLo, fluxMid, irradVar, irradAvg, p, d; |
| 107 |
|
|
Photon *photon; |
| 108 |
|
|
PhotonSearchQueueNode *sqn, *sqEnd; |
| 109 |
|
|
PhotonBiasCompNode *hist, *histEnd; |
| 110 |
greg |
2.1 |
|
| 111 |
|
|
if (!pmap -> biasCompHist) { |
| 112 |
|
|
/* Allocate bias compensation history */ |
| 113 |
rschregle |
2.5 |
numHi = pmap -> maxGather - pmap -> minGather; |
| 114 |
|
|
for (i = pmap -> minGather + 1; numHi > 1; numHi >>= 1, ++i); |
| 115 |
|
|
pmap -> biasCompHist = calloc(i, sizeof(PhotonBiasCompNode)); |
| 116 |
|
|
|
| 117 |
greg |
2.1 |
if (!pmap -> biasCompHist) |
| 118 |
|
|
error(USER, "can't allocate bias compensation history"); |
| 119 |
|
|
} |
| 120 |
|
|
|
| 121 |
rschregle |
2.5 |
numLo = min(pmap -> minGather, pmap -> squeue.tail - 1); |
| 122 |
|
|
numHi = min(pmap -> maxGather, pmap -> squeue.tail - 1); |
| 123 |
|
|
sqn = sqEnd = pmap -> squeue.node + pmap -> squeue.tail - 1; |
| 124 |
greg |
2.1 |
histEnd = pmap -> biasCompHist; |
| 125 |
|
|
setcolor(fluxLo, 0, 0, 0); |
| 126 |
|
|
|
| 127 |
|
|
/* Partition to get numLo closest photons starting from END of queue */ |
| 128 |
rschregle |
2.5 |
squeuePartition(sqEnd, 1, numLo + 1, numHi); |
| 129 |
greg |
2.1 |
|
| 130 |
|
|
/* Get irradiance estimates (ignoring 1 / PI) using 1..numLo photons |
| 131 |
|
|
and chuck in history. Queue is traversed BACKWARDS. */ |
| 132 |
rschregle |
2.5 |
for (i = 1; i <= numLo; i++, sqn--) { |
| 133 |
|
|
/* Make sure furthest two photons are consecutive w.r.t. distance */ |
| 134 |
|
|
squeuePartition(sqEnd, i, i + 1, numLo + 1); |
| 135 |
|
|
photon = getNearestPhoton(&pmap -> squeue, sqn -> idx); |
| 136 |
|
|
getPhotonFlux(photon, irrad); |
| 137 |
greg |
2.1 |
addcolor(fluxLo, irrad); |
| 138 |
|
|
/* Average radius between furthest two photons to improve accuracy */ |
| 139 |
rschregle |
2.5 |
r = 0.25 * (sqn -> dist2 + (sqn - 1) -> dist2 + |
| 140 |
|
|
2 * sqrt(sqn -> dist2 * (sqn - 1) -> dist2)); |
| 141 |
greg |
2.1 |
/* Add irradiance and weight to history. Weights should increase |
| 142 |
|
|
monotonically based on number of photons used for the estimate. */ |
| 143 |
|
|
histEnd -> irrad [0] = fluxLo [0] / r; |
| 144 |
|
|
histEnd -> irrad [1] = fluxLo [1] / r; |
| 145 |
|
|
histEnd -> irrad [2] = fluxLo [2] / r; |
| 146 |
|
|
totalWeight += histEnd++ -> weight = BIASCOMP_WGT((float)i); |
| 147 |
|
|
} |
| 148 |
|
|
|
| 149 |
|
|
/* Compute expected value (average) and variance of irradiance based on |
| 150 |
|
|
history for numLo photons. */ |
| 151 |
|
|
setcolor(irradAvg, 0, 0, 0); |
| 152 |
|
|
setcolor(irradVar, 0, 0, 0); |
| 153 |
|
|
|
| 154 |
|
|
for (hist = pmap -> biasCompHist; hist < histEnd; ++hist) |
| 155 |
|
|
for (i = 0; i <= 2; ++i) { |
| 156 |
|
|
irradAvg [i] += r = hist -> weight * hist -> irrad [i]; |
| 157 |
|
|
irradVar [i] += r * hist -> irrad [i]; |
| 158 |
|
|
} |
| 159 |
|
|
|
| 160 |
|
|
for (i = 0; i <= 2; ++i) { |
| 161 |
|
|
r = irradAvg [i] /= totalWeight; |
| 162 |
|
|
irradVar [i] = irradVar [i] / totalWeight - r * r; |
| 163 |
|
|
} |
| 164 |
|
|
|
| 165 |
|
|
/* Do binary search within interval [numLo, numHi]. numLo is towards |
| 166 |
|
|
the END of the queue. */ |
| 167 |
|
|
while (numHi - numLo > 1) { |
| 168 |
|
|
numMid = (numLo + numHi) >> 1; |
| 169 |
|
|
/* Split interval to get numMid closest photons starting from the |
| 170 |
|
|
END of the queue */ |
| 171 |
rschregle |
2.5 |
squeuePartition(sqEnd, numLo, numMid, numHi); |
| 172 |
greg |
2.1 |
/* Make sure furthest two photons are consecutive wrt distance */ |
| 173 |
rschregle |
2.5 |
squeuePartition(sqEnd, numMid, numMid + 1, numHi); |
| 174 |
greg |
2.1 |
copycolor(fluxMid, fluxLo); |
| 175 |
rschregle |
2.5 |
sqn = sqEnd - numLo; |
| 176 |
greg |
2.1 |
|
| 177 |
|
|
/* Get irradiance for numMid photons (ignoring 1 / PI) */ |
| 178 |
rschregle |
2.5 |
for (i = numLo; i < numMid; i++, sqn--) { |
| 179 |
|
|
photon = getNearestPhoton(&pmap -> squeue, sqn -> idx); |
| 180 |
|
|
getPhotonFlux(photon, irrad); |
| 181 |
greg |
2.1 |
addcolor(fluxMid, irrad); |
| 182 |
|
|
} |
| 183 |
|
|
|
| 184 |
|
|
/* Average radius between furthest two photons to improve accuracy */ |
| 185 |
rschregle |
2.5 |
r = 0.25 * (sqn -> dist2 + (sqn + 1) -> dist2 + |
| 186 |
|
|
2 * sqrt(sqn -> dist2 * (sqn + 1) -> dist2)); |
| 187 |
greg |
2.1 |
|
| 188 |
|
|
/* Get deviation from current average, and probability that it's due |
| 189 |
|
|
to noise from gaussian distribution based on current variance. Since |
| 190 |
|
|
we are doing this for each colour channel we can also detect |
| 191 |
|
|
chromatic bias. */ |
| 192 |
|
|
for (i = 0; i <= 2; ++i) { |
| 193 |
|
|
d [i] = irradAvg [i] - (irrad [i] = fluxMid [i] / r); |
| 194 |
|
|
p [i] = exp(-0.5 * d [i] * d [i] / irradVar [i]); |
| 195 |
|
|
} |
| 196 |
|
|
|
| 197 |
|
|
if (pmapRandom(pmap -> randState) < colorAvg(p)) { |
| 198 |
|
|
/* Deviation is probably noise, so add mid irradiance to history */ |
| 199 |
|
|
copycolor(histEnd -> irrad, irrad); |
| 200 |
|
|
totalWeight += histEnd++ -> weight = BIASCOMP_WGT((float)numMid); |
| 201 |
|
|
setcolor(irradAvg, 0, 0, 0); |
| 202 |
|
|
setcolor(irradVar, 0, 0, 0); |
| 203 |
|
|
|
| 204 |
|
|
/* Update average and variance */ |
| 205 |
|
|
for (hist = pmap -> biasCompHist; hist < histEnd; ++hist) |
| 206 |
|
|
for (i = 0; i <= 2; i++) { |
| 207 |
|
|
r = hist -> irrad [i]; |
| 208 |
|
|
irradAvg [i] += hist -> weight * r; |
| 209 |
|
|
irradVar [i] += hist -> weight * r * r; |
| 210 |
|
|
} |
| 211 |
|
|
|
| 212 |
|
|
for (i = 0; i <= 2; i++) { |
| 213 |
|
|
r = irradAvg [i] /= totalWeight; |
| 214 |
|
|
irradVar [i] = irradVar [i] / totalWeight - r * r; |
| 215 |
|
|
} |
| 216 |
|
|
|
| 217 |
rschregle |
2.5 |
/* Need more photons --> recurse on [numMid, numHi] */ |
| 218 |
greg |
2.1 |
numLo = numMid; |
| 219 |
|
|
copycolor(fluxLo, fluxMid); |
| 220 |
|
|
} |
| 221 |
|
|
else |
| 222 |
rschregle |
2.5 |
/* Deviation is probably bias --> need fewer photons, |
| 223 |
greg |
2.1 |
so recurse on [numLo, numMid] */ |
| 224 |
|
|
numHi = numMid; |
| 225 |
|
|
} |
| 226 |
|
|
|
| 227 |
|
|
--histEnd; |
| 228 |
rschregle |
2.5 |
|
| 229 |
greg |
2.1 |
for (i = 0; i <= 2; i++) { |
| 230 |
|
|
/* Estimated relative error */ |
| 231 |
|
|
d [i] = histEnd -> irrad [i] / irradAvg [i] - 1; |
| 232 |
|
|
|
| 233 |
|
|
#ifdef BIASCOMP_BWIDTH |
| 234 |
|
|
/* Return bandwidth instead of irradiance */ |
| 235 |
|
|
irrad [i] = numHi / PI; |
| 236 |
|
|
#else |
| 237 |
|
|
/* 1 / PI required as ambient normalisation factor */ |
| 238 |
|
|
irrad [i] = histEnd -> irrad [i] / (PI * PI); |
| 239 |
|
|
#endif |
| 240 |
|
|
} |
| 241 |
|
|
|
| 242 |
|
|
/* Update statistix */ |
| 243 |
|
|
r = colorAvg(d); |
| 244 |
rschregle |
2.5 |
pmap -> rmsError += r * r; |
| 245 |
|
|
|
| 246 |
greg |
2.1 |
if (r < pmap -> minError) |
| 247 |
|
|
pmap -> minError = r; |
| 248 |
rschregle |
2.5 |
|
| 249 |
greg |
2.1 |
if (r > pmap -> maxError) |
| 250 |
|
|
pmap -> maxError = r; |
| 251 |
|
|
|
| 252 |
|
|
if (numHi < pmap -> minGathered) |
| 253 |
|
|
pmap -> minGathered = numHi; |
| 254 |
rschregle |
2.5 |
|
| 255 |
greg |
2.1 |
if (numHi > pmap -> maxGathered) |
| 256 |
|
|
pmap -> maxGathered = numHi; |
| 257 |
|
|
|
| 258 |
|
|
pmap -> totalGathered += numHi; |
| 259 |
|
|
++pmap -> numDensity; |
| 260 |
|
|
} |
| 261 |
|
|
|
| 262 |
|
|
|
| 263 |
|
|
|
| 264 |
rschregle |
2.5 |
/* Volume bias compensation disabled (probably redundant) */ |
| 265 |
|
|
#if 0 |
| 266 |
greg |
2.1 |
void volumeBiasComp (PhotonMap* pmap, const RAY* ray, COLOR irrad) |
| 267 |
|
|
/* Photon volume density estimate with bias compensation -- czech dis |
| 268 |
|
|
shit out! */ |
| 269 |
|
|
{ |
| 270 |
|
|
unsigned i, numLo, numHi, numMid = 0; |
| 271 |
|
|
PhotonSQNode *sq; |
| 272 |
|
|
PhotonBCNode *hist; |
| 273 |
|
|
const float gecc2 = ray -> gecc * ray -> gecc; |
| 274 |
|
|
float r, totalWeight = 0; |
| 275 |
|
|
PhotonSQNode *squeueEnd; |
| 276 |
|
|
PhotonBCNode *histEnd; |
| 277 |
|
|
COLOR fluxLo, fluxMid, irradVar, irradAvg, p, d; |
| 278 |
|
|
|
| 279 |
|
|
if (!pmap -> biasCompHist) { |
| 280 |
|
|
/* Allocate bias compensation history */ |
| 281 |
|
|
numHi = pmap -> maxGather - pmap -> minGather; |
| 282 |
|
|
for (i = pmap -> minGather + 1; numHi > 1; numHi >>= 1, ++i); |
| 283 |
|
|
pmap -> biasCompHist = (PhotonBCNode*)malloc(i * sizeof(PhotonBCNode)); |
| 284 |
|
|
if (!pmap -> biasCompHist) |
| 285 |
|
|
error(USER, "can't allocate bias compensation history"); |
| 286 |
|
|
} |
| 287 |
|
|
|
| 288 |
|
|
numLo = min(pmap -> minGather, pmap -> squeueEnd - 1); |
| 289 |
|
|
numHi = min(pmap -> maxGather, pmap -> squeueEnd - 1); |
| 290 |
|
|
sq = squeueEnd = pmap -> squeue + pmap -> squeueEnd - 1; |
| 291 |
|
|
histEnd = pmap -> biasCompHist; |
| 292 |
|
|
setcolor(fluxLo, 0, 0, 0); |
| 293 |
|
|
/* Partition to get numLo closest photons starting from END of queue */ |
| 294 |
|
|
squeuePartition(squeueEnd, 1, numLo, numHi); |
| 295 |
|
|
|
| 296 |
|
|
/* Get irradiance estimates (ignoring constants) using 1..numLo photons |
| 297 |
|
|
and chuck in history. Queue is traversed BACKWARDS. */ |
| 298 |
|
|
for (i = 1; i <= numLo; i++, sq--) { |
| 299 |
|
|
/* Make sure furthest two photons are consecutive wrt distance */ |
| 300 |
|
|
squeuePartition(squeueEnd, i, i + 1, numHi); |
| 301 |
|
|
|
| 302 |
|
|
/* Compute phase function for inscattering from photon */ |
| 303 |
|
|
if (gecc2 <= FTINY) |
| 304 |
|
|
r = 1; |
| 305 |
|
|
else { |
| 306 |
|
|
r = DOT(ray -> rdir, sq -> photon -> norm) / 127; |
| 307 |
|
|
r = 1 + gecc2 - 2 * ray -> gecc * r; |
| 308 |
|
|
r = (1 - gecc2) / (r * sqrt(r)); |
| 309 |
|
|
} |
| 310 |
|
|
|
| 311 |
|
|
getPhotonFlux(sq -> photon, irrad); |
| 312 |
|
|
scalecolor(irrad, r); |
| 313 |
|
|
addcolor(fluxLo, irrad); |
| 314 |
|
|
/* Average radius between furthest two photons to improve accuracy */ |
| 315 |
|
|
r = 0.25 * (sq -> dist + (sq - 1) -> dist + |
| 316 |
|
|
2 * sqrt(sq -> dist * (sq - 1) -> dist)); |
| 317 |
|
|
r *= sqrt(r); |
| 318 |
|
|
/* Add irradiance and weight to history. Weights should increase |
| 319 |
|
|
monotonically based on number of photons used for the estimate. */ |
| 320 |
|
|
histEnd -> irrad [0] = fluxLo [0] / r; |
| 321 |
|
|
histEnd -> irrad [1] = fluxLo [1] / r; |
| 322 |
|
|
histEnd -> irrad [2] = fluxLo [2] / r; |
| 323 |
|
|
totalWeight += histEnd++ -> weight = BIASCOMP_WGT((float)i); |
| 324 |
|
|
} |
| 325 |
|
|
|
| 326 |
|
|
/* Compute expected value (average) and variance of irradiance based on |
| 327 |
|
|
history for numLo photons. */ |
| 328 |
|
|
setcolor(irradAvg, 0, 0, 0); |
| 329 |
|
|
setcolor(irradVar, 0, 0, 0); |
| 330 |
|
|
|
| 331 |
|
|
for (hist = pmap -> biasCompHist; hist < histEnd; ++hist) |
| 332 |
|
|
for (i = 0; i <= 2; ++i) { |
| 333 |
|
|
irradAvg [i] += r = hist -> weight * hist -> irrad [i]; |
| 334 |
|
|
irradVar [i] += r * hist -> irrad [i]; |
| 335 |
|
|
} |
| 336 |
|
|
|
| 337 |
|
|
for (i = 0; i <= 2; ++i) { |
| 338 |
|
|
r = irradAvg [i] /= totalWeight; |
| 339 |
|
|
irradVar [i] = irradVar [i] / totalWeight - r * r; |
| 340 |
|
|
} |
| 341 |
|
|
|
| 342 |
|
|
/* Do binary search within interval [numLo, numHi]. numLo is towards |
| 343 |
|
|
the END of the queue. */ |
| 344 |
|
|
while (numHi - numLo > 1) { |
| 345 |
|
|
numMid = (numLo + numHi) >> 1; |
| 346 |
|
|
/* Split interval to get numMid closest photons starting from the |
| 347 |
|
|
END of the queue */ |
| 348 |
|
|
squeuePartition(squeueEnd, numLo, numMid, numHi); |
| 349 |
|
|
/* Make sure furthest two photons are consecutive wrt distance */ |
| 350 |
|
|
squeuePartition(squeueEnd, numMid, numMid + 1, numHi); |
| 351 |
|
|
copycolor(fluxMid, fluxLo); |
| 352 |
|
|
sq = squeueEnd - numLo; |
| 353 |
|
|
|
| 354 |
|
|
/* Get irradiance for numMid photons (ignoring constants) */ |
| 355 |
|
|
for (i = numLo; i < numMid; i++, sq--) { |
| 356 |
|
|
/* Compute phase function for inscattering from photon */ |
| 357 |
|
|
if (gecc2 <= FTINY) |
| 358 |
|
|
r = 1; |
| 359 |
|
|
else { |
| 360 |
|
|
r = DOT(ray -> rdir, sq -> photon -> norm) / 127; |
| 361 |
|
|
r = 1 + gecc2 - 2 * ray -> gecc * r; |
| 362 |
|
|
r = (1 - gecc2) / (r * sqrt(r)); |
| 363 |
|
|
} |
| 364 |
|
|
|
| 365 |
|
|
getPhotonFlux(sq -> photon, irrad); |
| 366 |
|
|
scalecolor(irrad, r); |
| 367 |
|
|
addcolor(fluxMid, irrad); |
| 368 |
|
|
} |
| 369 |
|
|
|
| 370 |
|
|
/* Average radius between furthest two photons to improve accuracy */ |
| 371 |
|
|
r = 0.25 * (sq -> dist + (sq + 1) -> dist + |
| 372 |
|
|
2 * sqrt(sq -> dist * (sq + 1) -> dist)); |
| 373 |
|
|
r *= sqrt(r); |
| 374 |
|
|
|
| 375 |
|
|
/* Get deviation from current average, and probability that it's due |
| 376 |
|
|
to noise from gaussian distribution based on current variance. Since |
| 377 |
|
|
we are doing this for each colour channel we can also detect |
| 378 |
|
|
chromatic bias. */ |
| 379 |
|
|
for (i = 0; i <= 2; ++i) { |
| 380 |
|
|
d [i] = irradAvg [i] - (irrad [i] = fluxMid [i] / r); |
| 381 |
|
|
p [i] = exp(-0.5 * d [i] * d [i] / irradVar [i]); |
| 382 |
|
|
} |
| 383 |
|
|
|
| 384 |
|
|
if (pmapRandom(pmap -> randState) < colorAvg(p)) { |
| 385 |
|
|
/* Deviation is probably noise, so add mid irradiance to history */ |
| 386 |
|
|
copycolor(histEnd -> irrad, irrad); |
| 387 |
|
|
totalWeight += histEnd++ -> weight = BIASCOMP_WGT((float)numMid); |
| 388 |
|
|
setcolor(irradAvg, 0, 0, 0); |
| 389 |
|
|
setcolor(irradVar, 0, 0, 0); |
| 390 |
|
|
|
| 391 |
|
|
/* Update average and variance */ |
| 392 |
|
|
for (hist = pmap -> biasCompHist; hist < histEnd; ++hist) |
| 393 |
|
|
for (i = 0; i <= 2; i++) { |
| 394 |
|
|
r = hist -> irrad [i]; |
| 395 |
|
|
irradAvg [i] += hist -> weight * r; |
| 396 |
|
|
irradVar [i] += hist -> weight * r * r; |
| 397 |
|
|
} |
| 398 |
|
|
for (i = 0; i <= 2; i++) { |
| 399 |
|
|
r = irradAvg [i] /= totalWeight; |
| 400 |
|
|
irradVar [i] = irradVar [i] / totalWeight - r * r; |
| 401 |
|
|
} |
| 402 |
|
|
|
| 403 |
|
|
/* Need more photons -- recurse on [numMid, numHi] */ |
| 404 |
|
|
numLo = numMid; |
| 405 |
|
|
copycolor(fluxLo, fluxMid); |
| 406 |
|
|
} |
| 407 |
|
|
else |
| 408 |
|
|
/* Deviation is probably bias -- need fewer photons, |
| 409 |
|
|
so recurse on [numLo, numMid] */ |
| 410 |
|
|
numHi = numMid; |
| 411 |
|
|
} |
| 412 |
|
|
|
| 413 |
|
|
--histEnd; |
| 414 |
|
|
for (i = 0; i <= 2; i++) { |
| 415 |
|
|
/* Estimated relative error */ |
| 416 |
|
|
d [i] = histEnd -> irrad [i] / irradAvg [i] - 1; |
| 417 |
|
|
/* Divide by 4 / 3 * PI for search volume (r^3 already accounted |
| 418 |
|
|
for) and phase function normalization factor 1 / (4 * PI) */ |
| 419 |
|
|
irrad [i] = histEnd -> irrad [i] * 3 / (16 * PI * PI); |
| 420 |
|
|
} |
| 421 |
|
|
|
| 422 |
|
|
/* Update statistix */ |
| 423 |
|
|
r = colorAvg(d); |
| 424 |
|
|
if (r < pmap -> minError) |
| 425 |
|
|
pmap -> minError = r; |
| 426 |
|
|
if (r > pmap -> maxError) |
| 427 |
|
|
pmap -> maxError = r; |
| 428 |
|
|
pmap -> rmsError += r * r; |
| 429 |
|
|
|
| 430 |
|
|
if (numMid < pmap -> minGathered) |
| 431 |
|
|
pmap -> minGathered = numMid; |
| 432 |
|
|
if (numMid > pmap -> maxGathered) |
| 433 |
|
|
pmap -> maxGathered = numMid; |
| 434 |
|
|
|
| 435 |
|
|
pmap -> totalGathered += numMid; |
| 436 |
|
|
++pmap -> numDensity; |
| 437 |
|
|
} |
| 438 |
rschregle |
2.5 |
#endif |
