opticalflow.cpp 21.7 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539
/*
 * By downloading, copying, installing or using the software you agree to this license.
 * If you do not agree to this license, do not download, install,
 * copy or use the software.
 *
 *
 *                           License Agreement
 *                For Open Source Computer Vision Library
 *                        (3-clause BSD License)
 *
 * Copyright (C) 2012-2015, NVIDIA Corporation, all rights reserved.
 * Third party copyrights are property of their respective owners.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *
 *   * Neither the names of the copyright holders nor the names of the contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.
 *
 * This software is provided by the copyright holders and contributors "as is" and
 * any express or implied warranties, including, but not limited to, the implied
 * warranties of merchantability and fitness for a particular purpose are disclaimed.
 * In no event shall copyright holders or contributors be liable for any direct,
 * indirect, incidental, special, exemplary, or consequential damages
 * (including, but not limited to, procurement of substitute goods or services;
 * loss of use, data, or profits; or business interruption) however caused
 * and on any theory of liability, whether in contract, strict liability,
 * or tort (including negligence or otherwise) arising in any way out of
 * the use of this software, even if advised of the possibility of such damage.
 */

#include "common.hpp"
#include "saturate_cast.hpp"
#include <vector>
#include <float.h> // For FLT_EPSILON

namespace CAROTENE_NS {

#define CV_DESCALE(x,n)     (((x) + (1 << ((n)-1))) >> (n))

/*
 *        Pyramidal Lucas-Kanade Optical Flow level processing
 */
void pyrLKOptFlowLevel(const Size2D &size, s32 cn,
                       const u8 *prevData, ptrdiff_t prevStride,
                       const s16 *prevDerivData, ptrdiff_t prevDerivStride,
                       const u8 *nextData, ptrdiff_t nextStride,
                       u32 ptCount,
                       const f32 *prevPts, f32 *nextPts,
                       u8 *status, f32 *err,
                       const Size2D &winSize,
                       u32 terminationCount, f64 terminationEpsilon,
                       u32 level, u32 maxLevel, bool useInitialFlow, bool getMinEigenVals,
                       f32 minEigThreshold)
{
    internal::assertSupportedConfiguration();
#ifdef CAROTENE_NEON
    f32 halfWinX = (winSize.width-1)*0.5f, halfWinY = (winSize.height-1)*0.5f;
    s32 cn2 = cn*2;

    std::vector<s16> _buf(winSize.total()*(cn + cn2));
    s16* IWinBuf = &_buf[0];
    s32  IWinBufStride = winSize.width*cn;
    s16* derivIWinBuf = &_buf[winSize.total()*cn];
    s32  derivIWinBufStride = winSize.width*cn2;

    for( u32 ptidx = 0; ptidx < ptCount; ptidx++ )
    {
        f32 levscale = (1./(1 << level));
        u32 ptref = ptidx << 1;
        f32 prevPtX = prevPts[ptref+0]*levscale;
        f32 prevPtY = prevPts[ptref+1]*levscale;
        f32 nextPtX;
        f32 nextPtY;
        if( level == maxLevel )
        {
            if( useInitialFlow )
            {
                nextPtX = nextPts[ptref+0]*levscale;
                nextPtY = nextPts[ptref+1]*levscale;
            }
            else
            {
                nextPtX = prevPtX;
                nextPtY = prevPtY;
            }
        }
        else
        {
            nextPtX = nextPts[ptref+0]*2.f;
            nextPtY = nextPts[ptref+1]*2.f;
        }
        nextPts[ptref+0] = nextPtX;
        nextPts[ptref+1] = nextPtY;

        s32 iprevPtX, iprevPtY;
        s32 inextPtX, inextPtY;
        prevPtX -= halfWinX;
        prevPtY -= halfWinY;
        iprevPtX = floor(prevPtX);
        iprevPtY = floor(prevPtY);

        if( iprevPtX < -(s32)winSize.width || iprevPtX >= (s32)size.width ||
            iprevPtY < -(s32)winSize.height || iprevPtY >= (s32)size.height )
        {
            if( level == 0 )
            {
                if( status )
                    status[ptidx] = false;
                if( err )
                    err[ptidx] = 0;
            }
            continue;
        }

        f32 a = prevPtX - iprevPtX;
        f32 b = prevPtY - iprevPtY;
        const s32 W_BITS = 14, W_BITS1 = 14;
        const f32 FLT_SCALE = 1.f/(1 << 20);
        s32 iw00 = round((1.f - a)*(1.f - b)*(1 << W_BITS));
        s32 iw01 = round(a*(1.f - b)*(1 << W_BITS));
        s32 iw10 = round((1.f - a)*b*(1 << W_BITS));
        s32 iw11 = (1 << W_BITS) - iw00 - iw01 - iw10;

        s32 dstep = prevDerivStride/sizeof(s16);
        f32 A11 = 0, A12 = 0, A22 = 0;

        int16x4_t viw00 = vmov_n_s16((s16)iw00);
        int16x4_t viw01 = vmov_n_s16((s16)iw01);
        int16x4_t viw10 = vmov_n_s16((s16)iw10);
        int16x4_t viw11 = vmov_n_s16((s16)iw11);

        float32x4_t vA11 = vmovq_n_f32(0);
        float32x4_t vA12 = vmovq_n_f32(0);
        float32x4_t vA22 = vmovq_n_f32(0);

        s32 wwcn = winSize.width*cn;

        // extract the patch from the first image, compute covariation matrix of derivatives
        s32 x = 0;
        for(s32 y = 0; y < (s32)winSize.height; y++ )
        {
            const u8* src = prevData + prevStride*(y + iprevPtY) + iprevPtX*cn;
            const s16* dsrc = prevDerivData + dstep*(y + iprevPtY) + iprevPtX*cn2;

            s16* Iptr = IWinBuf + y*IWinBufStride;
            s16* dIptr = derivIWinBuf + y*derivIWinBufStride;

            internal::prefetch(src + x + prevStride * 2, 0);
            for(x = 0; x <= wwcn - 8; x += 8)
            {
                uint8x8_t vsrc00 = vld1_u8(src + x);
                uint8x8_t vsrc10 = vld1_u8(src + x + prevStride);
                uint8x8_t vsrc01 = vld1_u8(src + x + cn);
                uint8x8_t vsrc11 = vld1_u8(src + x + prevStride + cn);

                int16x8_t vs00 = vreinterpretq_s16_u16(vmovl_u8(vsrc00));
                int16x8_t vs10 = vreinterpretq_s16_u16(vmovl_u8(vsrc10));
                int16x8_t vs01 = vreinterpretq_s16_u16(vmovl_u8(vsrc01));
                int16x8_t vs11 = vreinterpretq_s16_u16(vmovl_u8(vsrc11));

                int32x4_t vsuml = vmull_s16(vget_low_s16(vs00), viw00);
                int32x4_t vsumh = vmull_s16(vget_high_s16(vs10), viw10);

                vsuml = vmlal_s16(vsuml, vget_low_s16(vs01), viw01);
                vsumh = vmlal_s16(vsumh, vget_high_s16(vs11), viw11);

                vsuml = vmlal_s16(vsuml, vget_low_s16(vs10), viw10);
                vsumh = vmlal_s16(vsumh, vget_high_s16(vs00), viw00);

                vsuml = vmlal_s16(vsuml, vget_low_s16(vs11), viw11);
                vsumh = vmlal_s16(vsumh, vget_high_s16(vs01), viw01);

                int16x4_t vsumnl = vrshrn_n_s32(vsuml, W_BITS1-5);
                int16x4_t vsumnh = vrshrn_n_s32(vsumh, W_BITS1-5);

                vst1q_s16(Iptr + x, vcombine_s16(vsumnl, vsumnh));
            }
            for(; x <= wwcn - 4; x += 4)
            {
                uint8x8_t vsrc00 = vld1_u8(src + x);
                uint8x8_t vsrc10 = vld1_u8(src + x + prevStride);
                uint8x8_t vsrc01 = vld1_u8(src + x + cn);
                uint8x8_t vsrc11 = vld1_u8(src + x + prevStride + cn);

                int16x4_t vs00 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(vsrc00)));
                int16x4_t vs10 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(vsrc10)));
                int16x4_t vs01 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(vsrc01)));
                int16x4_t vs11 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(vsrc11)));

                int32x4_t vsuml1 = vmull_s16(vs00, viw00);
                int32x4_t vsuml2 = vmull_s16(vs01, viw01);
                vsuml1 = vmlal_s16(vsuml1, vs10, viw10);
                vsuml2 = vmlal_s16(vsuml2, vs11, viw11);
                int32x4_t vsuml = vaddq_s32(vsuml1, vsuml2);

                int16x4_t vsumnl = vrshrn_n_s32(vsuml, W_BITS1-5);

                vst1_s16(Iptr + x, vsumnl);
            }

            internal::prefetch(dsrc + dstep * 2, 0);
            for(x = 0; x <= wwcn - 4; x += 4, dsrc += 4*2, dIptr += 4*2 )
            {
#if 0
                __asm__ (
                    "vld2.16 {d0-d1}, [%[dsrc00]]                         \n\t"
                    "vld2.16 {d2-d3}, [%[dsrc10]]                         \n\t"
                    "vld2.16 {d4-d5}, [%[dsrc01]]                         \n\t"
                    "vld2.16 {d6-d7}, [%[dsrc11]]                         \n\t"
                    "vmull.s16 q4, d3, %P[viw10]                           \n\t"
                    "vmull.s16 q5, d0, %P[viw00]                           \n\t"
                    "vmlal.s16 q4, d7, %P[viw11]                           \n\t"
                    "vmlal.s16 q5, d4, %P[viw01]                           \n\t"
                    "vmlal.s16 q4, d1, %P[viw00]                           \n\t"
                    "vmlal.s16 q5, d2, %P[viw10]                           \n\t"
                    "vmlal.s16 q4, d5, %P[viw01]                           \n\t"
                    "vmlal.s16 q5, d6, %P[viw11]                            \n\t"
                    "vrshrn.s32 d13, q4, %[W_BITS1]                       \n\t"
                    "vrshrn.s32 d12, q5, %[W_BITS1]                       \n\t"
                    "vmull.s16 q3, d13, d13                               \n\t"
                    "vmull.s16 q4, d12, d12                               \n\t"
                    "vmull.s16 q5, d13, d12                               \n\t"
                    "vcvt.f32.s32 q3, q3                                  \n\t"
                    "vcvt.f32.s32 q4, q4                                  \n\t"
                    "vcvt.f32.s32 q5, q5                                  \n\t"
                    "vadd.f32 %q[vA22], q3                                \n\t"
                    "vadd.f32 %q[vA11], q4                                \n\t"
                    "vadd.f32 %q[vA12], q5                                \n\t"
                    "vst2.16 {d12-d13}, [%[out]]                          \n\t"
                    : [vA22] "=w" (vA22),
                      [vA11] "=w" (vA11),
                      [vA12] "=w" (vA12)
                    : "0" (vA22),
                      "1" (vA11),
                      "2" (vA12),
                      [out] "r" (dIptr),
                      [dsrc00] "r" (dsrc),
                      [dsrc10] "r" (dsrc + dstep),
                      [dsrc01] "r" (dsrc + cn2),
                      [dsrc11] "r" (dsrc + dstep + cn2),
                      [viw00] "w" (viw00),
                      [viw10] "w" (viw10),
                      [viw01] "w" (viw01),
                      [viw11] "w" (viw11),
                      [W_BITS1] "I" (W_BITS1)
                    : "d0","d1","d2","d3","d4","d5","d6","d7","d8","d9","d10","d11","d12","d13"
                );
#else
                int16x4x2_t vdsrc00 = vld2_s16(dsrc);
                int16x4x2_t vdsrc10 = vld2_s16(dsrc + dstep);
                int16x4x2_t vdsrc01 = vld2_s16(dsrc + cn2);
                int16x4x2_t vdsrc11 = vld2_s16(dsrc + dstep + cn2);

                int32x4_t vsumy = vmull_s16(vdsrc10.val[1], viw10);
                int32x4_t vsumx = vmull_s16(vdsrc00.val[0], viw00);

                vsumy = vmlal_s16(vsumy, vdsrc11.val[1], viw11);
                vsumx = vmlal_s16(vsumx, vdsrc01.val[0], viw01);

                vsumy = vmlal_s16(vsumy, vdsrc00.val[1], viw00);
                vsumx = vmlal_s16(vsumx, vdsrc10.val[0], viw10);

                vsumy = vmlal_s16(vsumy, vdsrc01.val[1], viw01);
                vsumx = vmlal_s16(vsumx, vdsrc11.val[0], viw11);

                int16x4_t vsumny = vrshrn_n_s32(vsumy, W_BITS1);
                int16x4_t vsumnx = vrshrn_n_s32(vsumx, W_BITS1);

                int32x4_t va22i = vmull_s16(vsumny, vsumny);
                int32x4_t va11i = vmull_s16(vsumnx, vsumnx);
                int32x4_t va12i = vmull_s16(vsumnx, vsumny);

                float32x4_t va22f = vcvtq_f32_s32(va22i);
                float32x4_t va11f = vcvtq_f32_s32(va11i);
                float32x4_t va12f = vcvtq_f32_s32(va12i);

                vA22 = vaddq_f32(vA22, va22f);
                vA11 = vaddq_f32(vA11, va11f);
                vA12 = vaddq_f32(vA12, va12f);

                int16x4x2_t vsum;
                vsum.val[0] = vsumnx;
                vsum.val[1] = vsumny;
                vst2_s16(dIptr, vsum);
#endif
            }

            for( ; x < wwcn; x++, dsrc += 2, dIptr += 2 )
            {
                s32 ival = CV_DESCALE(src[x]*iw00 + src[x+cn]*iw01 +
                                      src[x+prevStride]*iw10 + src[x+prevStride+cn]*iw11, W_BITS1-5);
                s32 ixval = CV_DESCALE(dsrc[0]*iw00 + dsrc[cn2]*iw01 +
                                       dsrc[dstep]*iw10 + dsrc[dstep+cn2]*iw11, W_BITS1);
                s32 iyval = CV_DESCALE(dsrc[1]*iw00 + dsrc[cn2+1]*iw01 + dsrc[dstep+1]*iw10 +
                                       dsrc[dstep+cn2+1]*iw11, W_BITS1);
                Iptr[x] = (s16)ival;
                dIptr[0] = (s16)ixval;
                dIptr[1] = (s16)iyval;

                A11 += (f32)(ixval*ixval);
                A12 += (f32)(ixval*iyval);
                A22 += (f32)(iyval*iyval);
            }
        }

        f32 A11buf[2], A12buf[2], A22buf[2];
        vst1_f32(A11buf, vadd_f32(vget_low_f32(vA11), vget_high_f32(vA11)));
        vst1_f32(A12buf, vadd_f32(vget_low_f32(vA12), vget_high_f32(vA12)));
        vst1_f32(A22buf, vadd_f32(vget_low_f32(vA22), vget_high_f32(vA22)));
        A11 += A11buf[0] + A11buf[1];
        A12 += A12buf[0] + A12buf[1];
        A22 += A22buf[0] + A22buf[1];

        A11 *= FLT_SCALE;
        A12 *= FLT_SCALE;
        A22 *= FLT_SCALE;

        f32 D = A11*A22 - A12*A12;
        f32 minEig = (A22 + A11 - std::sqrt((A11-A22)*(A11-A22) +
                        4.f*A12*A12))/(2*winSize.width*winSize.height);

        if( err && getMinEigenVals )
            err[ptidx] = (f32)minEig;

        if( minEig < minEigThreshold || D < FLT_EPSILON )
        {
            if( level == 0 && status )
                status[ptidx] = false;
            continue;
        }

        D = 1.f/D;

        nextPtX -= halfWinX;
        nextPtY -= halfWinY;
        f32 prevDeltaX = 0;
        f32 prevDeltaY = 0;

        for(u32 j = 0; j < terminationCount; j++ )
        {
            inextPtX = floor(nextPtX);
            inextPtY = floor(nextPtY);

            if( inextPtX < -(s32)winSize.width || inextPtX >= (s32)size.width ||
               inextPtY < -(s32)winSize.height || inextPtY >= (s32)size.height )
            {
                if( level == 0 && status )
                    status[ptidx] = false;
                break;
            }

            a = nextPtX - inextPtX;
            b = nextPtY - inextPtY;
            iw00 = round((1.f - a)*(1.f - b)*(1 << W_BITS));
            iw01 = round(a*(1.f - b)*(1 << W_BITS));
            iw10 = round((1.f - a)*b*(1 << W_BITS));
            iw11 = (1 << W_BITS) - iw00 - iw01 - iw10;
            f32 b1 = 0, b2 = 0;

            viw00 = vmov_n_s16((s16)iw00);
            viw01 = vmov_n_s16((s16)iw01);
            viw10 = vmov_n_s16((s16)iw10);
            viw11 = vmov_n_s16((s16)iw11);

            float32x4_t vb1 = vmovq_n_f32(0);
            float32x4_t vb2 = vmovq_n_f32(0);

            for(s32 y = 0; y < (s32)winSize.height; y++ )
            {
                const u8* Jptr = nextData + nextStride*(y + inextPtY) + inextPtX*cn;
                const s16* Iptr = IWinBuf + y*IWinBufStride;
                const s16* dIptr = derivIWinBuf + y*derivIWinBufStride;

                x = 0;

                internal::prefetch(Jptr, nextStride * 2);
                internal::prefetch(Iptr, IWinBufStride/2);
                internal::prefetch(dIptr, derivIWinBufStride/2);

                for( ; x <= wwcn - 8; x += 8, dIptr += 8*2 )
                {
                    uint8x8_t vj00 = vld1_u8(Jptr + x);
                    uint8x8_t vj10 = vld1_u8(Jptr + x + nextStride);
                    uint8x8_t vj01 = vld1_u8(Jptr + x + cn);
                    uint8x8_t vj11 = vld1_u8(Jptr + x + nextStride + cn);
                    int16x8_t vI = vld1q_s16(Iptr + x);
                    int16x8x2_t vDerivI = vld2q_s16(dIptr);

                    int16x8_t vs00 = vreinterpretq_s16_u16(vmovl_u8(vj00));
                    int16x8_t vs10 = vreinterpretq_s16_u16(vmovl_u8(vj10));
                    int16x8_t vs01 = vreinterpretq_s16_u16(vmovl_u8(vj01));
                    int16x8_t vs11 = vreinterpretq_s16_u16(vmovl_u8(vj11));

                    int32x4_t vsuml = vmull_s16(vget_low_s16(vs00), viw00);
                    int32x4_t vsumh = vmull_s16(vget_high_s16(vs10), viw10);

                    vsuml = vmlal_s16(vsuml, vget_low_s16(vs01), viw01);
                    vsumh = vmlal_s16(vsumh, vget_high_s16(vs11), viw11);

                    vsuml = vmlal_s16(vsuml, vget_low_s16(vs10), viw10);
                    vsumh = vmlal_s16(vsumh, vget_high_s16(vs00), viw00);

                    vsuml = vmlal_s16(vsuml, vget_low_s16(vs11), viw11);
                    vsumh = vmlal_s16(vsumh, vget_high_s16(vs01), viw01);

                    int16x4_t vsumnl = vrshrn_n_s32(vsuml, W_BITS1-5);
                    int16x4_t vsumnh = vrshrn_n_s32(vsumh, W_BITS1-5);

                    int16x8_t diff = vqsubq_s16(vcombine_s16(vsumnl, vsumnh), vI);

                    int32x4_t vb1l = vmull_s16(vget_low_s16(diff), vget_low_s16(vDerivI.val[0]));
                    int32x4_t vb2h = vmull_s16(vget_high_s16(diff), vget_high_s16(vDerivI.val[1]));
                    int32x4_t vb1i = vmlal_s16(vb1l, vget_high_s16(diff), vget_high_s16(vDerivI.val[0]));
                    int32x4_t vb2i = vmlal_s16(vb2h, vget_low_s16(diff), vget_low_s16(vDerivI.val[1]));

                    float32x4_t vb1f = vcvtq_f32_s32(vb1i);
                    float32x4_t vb2f = vcvtq_f32_s32(vb2i);

                    vb1 = vaddq_f32(vb1, vb1f);
                    vb2 = vaddq_f32(vb2, vb2f);
                }

                for( ; x < wwcn; x++, dIptr += 2 )
                {
                    s32 diff = CV_DESCALE(Jptr[x]*iw00 + Jptr[x+cn]*iw01 +
                                          Jptr[x+nextStride]*iw10 + Jptr[x+nextStride+cn]*iw11,
                                          W_BITS1-5) - Iptr[x];
                    b1 += (f32)(diff*dIptr[0]);
                    b2 += (f32)(diff*dIptr[1]);
                }
            }

            f32 bbuf[2];
            float32x2_t vb = vpadd_f32(vadd_f32(vget_low_f32(vb1), vget_high_f32(vb1)), vadd_f32(vget_low_f32(vb2), vget_high_f32(vb2)));
            vst1_f32(bbuf, vb);
            b1 += bbuf[0];
            b2 += bbuf[1];

            b1 *= FLT_SCALE;
            b2 *= FLT_SCALE;

            f32 deltaX = (f32)((A12*b2 - A22*b1) * D);
            f32 deltaY = (f32)((A12*b1 - A11*b2) * D);

            nextPtX += deltaX;
            nextPtY += deltaY;
            nextPts[ptref+0] = nextPtX + halfWinX;
            nextPts[ptref+1] = nextPtY + halfWinY;

            if( ((double)deltaX*deltaX + (double)deltaY*deltaY) <= terminationEpsilon )
                break;

            if( j > 0 && std::abs(deltaX + prevDeltaX) < 0.01 &&
               std::abs(deltaY + prevDeltaY) < 0.01 )
            {
                nextPts[ptref+0] -= deltaX*0.5f;
                nextPts[ptref+1] -= deltaY*0.5f;
                break;
            }
            prevDeltaX = deltaX;
            prevDeltaY = deltaY;
        }

        if( status && status[ptidx] && err && level == 0 && !getMinEigenVals )
        {
            f32 nextPointX = nextPts[ptref+0] - halfWinX;
            f32 nextPointY = nextPts[ptref+1] - halfWinY;

            s32 inextPointX = floor(nextPointX);
            s32 inextPointY = floor(nextPointY);

            if( inextPointX < -(s32)winSize.width || inextPointX >= (s32)size.width ||
                inextPointY < -(s32)winSize.height || inextPointY >= (s32)size.height )
            {
                if( status )
                    status[ptidx] = false;
                continue;
            }

            f32 aa = nextPointX - inextPointX;
            f32 bb = nextPointY - inextPointY;
            iw00 = round((1.f - aa)*(1.f - bb)*(1 << W_BITS));
            iw01 = round(aa*(1.f - bb)*(1 << W_BITS));
            iw10 = round((1.f - aa)*bb*(1 << W_BITS));
            iw11 = (1 << W_BITS) - iw00 - iw01 - iw10;
            f32 errval = 0.f;

            for(s32 y = 0; y < (s32)winSize.height; y++ )
            {
                const u8* Jptr = nextData + nextStride*(y + inextPointY) + inextPointX*cn;
                const s16* Iptr = IWinBuf + y*IWinBufStride;

                for( x = 0; x < wwcn; x++ )
                {
                    s32 diff = CV_DESCALE(Jptr[x]*iw00 + Jptr[x+cn]*iw01 +
                                          Jptr[x+nextStride]*iw10 + Jptr[x+nextStride+cn]*iw11,
                                          W_BITS1-5) - Iptr[x];
                    errval += std::abs((f32)diff);
                }
            }
            err[ptidx] = errval / (32*wwcn*winSize.height);
        }
    }
#else
    (void)size;
    (void)cn;
    (void)prevData;
    (void)prevStride;
    (void)prevDerivData;
    (void)prevDerivStride;
    (void)nextData;
    (void)nextStride;
    (void)prevPts;
    (void)nextPts;
    (void)status;
    (void)err;
    (void)winSize;
    (void)terminationCount;
    (void)terminationEpsilon;
    (void)level;
    (void)maxLevel;
    (void)useInitialFlow;
    (void)getMinEigenVals;
    (void)minEigThreshold;
    (void)ptCount;
#endif
}

}//CAROTENE_NS