From f1e8aa70a01505939a6ded0fc75d5503bf146806 Mon Sep 17 00:00:00 2001 From: Rostislav Vasilikhin Date: Thu, 17 Aug 2017 02:14:42 +0300 Subject: [PATCH] added checksum-based test for Lab bit-exactness --- modules/imgproc/test/test_color.cpp | 320 ++++++++++++++++++++++++++++++++++++ 1 file changed, 320 insertions(+) diff --git a/modules/imgproc/test/test_color.cpp b/modules/imgproc/test/test_color.cpp index f18853a..4677b01 100644 --- a/modules/imgproc/test/test_color.cpp +++ b/modules/imgproc/test/test_color.cpp @@ -2110,6 +2110,326 @@ TEST(Imgproc_ColorLab_Full, accuracy) } } + +static uint32_t adler32(Mat m) +{ + uint32_t s1 = 1, s2 = 0; + for(int y = 0; y < m.rows; y++) + { + uchar* py = m.ptr(y); + for(size_t x = 0; x < m.cols*m.elemSize(); x++) + { + s1 = (s1 + py[x]) % 65521; + s2 = (s1 + s2 ) % 65521; + } + } + return (s2 << 16) + s1; +} + + +// taken from color.cpp + +static ushort sRGBGammaTab_b[256], linearGammaTab_b[256]; +enum { inv_gamma_shift = 12, INV_GAMMA_TAB_SIZE = (1 << inv_gamma_shift) }; +static ushort sRGBInvGammaTab_b[INV_GAMMA_TAB_SIZE], linearInvGammaTab_b[INV_GAMMA_TAB_SIZE]; +#undef lab_shift +// #define lab_shift xyz_shift +#define lab_shift 12 +#define gamma_shift 3 +#define lab_shift2 (lab_shift + gamma_shift) +#define LAB_CBRT_TAB_SIZE_B (256*3/2*(1<> (n)) + +static ushort LabToYF_b[256*2]; +static const int minABvalue = -8145; +static int abToXZ_b[LAB_BASE*9/4]; + +static void initLabTabs() +{ + static bool initialized = false; + if(!initialized) + { + static const softfloat lthresh = softfloat(216) / softfloat(24389); // 0.008856f = (6/29)^3 + static const softfloat lscale = softfloat(841) / softfloat(108); // 7.787f = (29/3)^3/(29*4) + static const softfloat lbias = softfloat(16) / softfloat(116); + static const softfloat f255(255); + + static const softfloat intScale(255*(1 << gamma_shift)); + for(int i = 0; i < 256; i++) + { + softfloat x = softfloat(i)/f255; + sRGBGammaTab_b[i] = (ushort)(cvRound(intScale*applyGamma(x))); + linearGammaTab_b[i] = (ushort)(i*(1 << gamma_shift)); + } + static const softfloat invScale = softfloat::one()/softfloat((int)INV_GAMMA_TAB_SIZE); + for(int i = 0; i < INV_GAMMA_TAB_SIZE; i++) + { + softfloat x = invScale*softfloat(i); + sRGBInvGammaTab_b[i] = (ushort)(cvRound(f255*applyInvGamma(x))); + linearInvGammaTab_b[i] = (ushort)(cvTrunc(f255*x)); + } + + static const softfloat cbTabScale(softfloat::one()/(f255*(1 << gamma_shift))); + static const softfloat lshift2(1 << lab_shift2); + for(int i = 0; i < LAB_CBRT_TAB_SIZE_B; i++) + { + softfloat x = cbTabScale*softfloat(i); + LabCbrtTab_b[i] = (ushort)(cvRound(lshift2 * (x < lthresh ? mulAdd(x, lscale, lbias) : cbrt(x)))); + } + + //Lookup table for L to y and ify calculations + static const int BASE = (1 << 14); + for(int i = 0; i < 256; i++) + { + int y, ify; + //8 * 255.0 / 100.0 == 20.4 + if( i <= 20) + { + //yy = li / 903.3f; + //y = L*100/903.3f; 903.3f = (29/3)^3, 255 = 17*3*5 + y = cvRound(softfloat(i*BASE*20*9)/softfloat(17*29*29*29)); + //fy = 7.787f * yy + 16.0f / 116.0f; 7.787f = (29/3)^3/(29*4) + ify = cvRound(softfloat(BASE)*(softfloat(16)/softfloat(116) + softfloat(i*5)/softfloat(3*17*29))); + } + else + { + //fy = (li + 16.0f) / 116.0f; + softfloat fy = (softfloat(i*100*BASE)/softfloat(255*116) + + softfloat(16*BASE)/softfloat(116)); + ify = cvRound(fy); + //yy = fy * fy * fy; + y = cvRound(fy*fy*fy/softfloat(BASE*BASE)); + } + + LabToYF_b[i*2 ] = (ushort)y; // 2260 <= y <= BASE + LabToYF_b[i*2+1] = (ushort)ify; // 0 <= ify <= BASE + } + + //Lookup table for a,b to x,z conversion + for(int i = minABvalue; i < LAB_BASE*9/4+minABvalue; i++) + { + int v; + //6.f/29.f*BASE = 3389.730 + if(i <= 3390) + { + //fxz[k] = (fxz[k] - 16.0f / 116.0f) / 7.787f; + // 7.787f = (29/3)^3/(29*4) + v = i*108/841 - BASE*16/116*108/841; + } + else + { + //fxz[k] = fxz[k] * fxz[k] * fxz[k]; + v = i*i/BASE*i/BASE; + } + abToXZ_b[i-minABvalue] = v; // -1335 <= v <= 88231 + } + + initialized = true; + } +} + +static int row8uRGB2Lab(const uchar* src_row, uchar *dst_row, int n, int cn, int blue_idx, bool srgb) +{ + int coeffs[9]; + softdouble whitept[3] = {Xn, softdouble::one(), Zn}; + + static const softdouble lshift(1 << lab_shift); + for(int i = 0; i < 3; i++) + { + coeffs[i*3 + (blue_idx^2)] = cvRound(lshift*RGB2XYZ[i*3 ]/whitept[i]); + coeffs[i*3 + 1 ] = cvRound(lshift*RGB2XYZ[i*3+1]/whitept[i]); + coeffs[i*3 + (blue_idx )] = cvRound(lshift*RGB2XYZ[i*3+2]/whitept[i]); + } + + const int Lscale = (116*255+50)/100; + const int Lshift = -((16*255*(1 << lab_shift2) + 50)/100); + const ushort* tab = srgb ? sRGBGammaTab_b : linearGammaTab_b; + for (int x = 0; x < n; x++) + { + int R = src_row[x*cn + 0], + G = src_row[x*cn + 1], + B = src_row[x*cn + 2]; + R = tab[R], G = tab[G], B = tab[B]; + int fX = LabCbrtTab_b[CV_DESCALE(R*coeffs[0] + G*coeffs[1] + B*coeffs[2], lab_shift)]; + int fY = LabCbrtTab_b[CV_DESCALE(R*coeffs[3] + G*coeffs[4] + B*coeffs[5], lab_shift)]; + int fZ = LabCbrtTab_b[CV_DESCALE(R*coeffs[6] + G*coeffs[7] + B*coeffs[8], lab_shift)]; + + int L = CV_DESCALE( Lscale*fY + Lshift, lab_shift2 ); + int a = CV_DESCALE( 500*(fX - fY) + 128*(1 << lab_shift2), lab_shift2 ); + int b = CV_DESCALE( 200*(fY - fZ) + 128*(1 << lab_shift2), lab_shift2 ); + + dst_row[x*3 ] = saturate_cast(L); + dst_row[x*3 + 1] = saturate_cast(a); + dst_row[x*3 + 2] = saturate_cast(b); + } + + return n; +} + + +int row8uLab2RGB(const uchar* src_row, uchar *dst_row, int n, int cn, int blue_idx, bool srgb) +{ + static const int base_shift = 14; + static const int BASE = (1 << base_shift); + static const int shift = lab_shift+(base_shift-inv_gamma_shift); + + int coeffs[9]; + softdouble whitept[3] = {Xn, softdouble::one(), Zn}; + + static const softdouble lshift(1 << lab_shift); + for(int i = 0; i < 3; i++) + { + coeffs[i+(blue_idx )*3] = cvRound(lshift*XYZ2RGB[i ]*whitept[i]); + coeffs[i+ 1*3] = cvRound(lshift*XYZ2RGB[i+3]*whitept[i]); + coeffs[i+(blue_idx^2)*3] = cvRound(lshift*XYZ2RGB[i+6]*whitept[i]); + } + ushort* tab = srgb ? sRGBInvGammaTab_b : linearInvGammaTab_b; + + for(int x = 0; x < n; x++) + { + uchar LL = src_row[x*3 ]; + uchar aa = src_row[x*3 + 1]; + uchar bb = src_row[x*3 + 2]; + + int ro, go, bo, xx, yy, zz, ify; + + yy = LabToYF_b[LL*2 ]; + ify = LabToYF_b[LL*2+1]; + + int adiv, bdiv; + //adiv = aa*BASE/500 - 128*BASE/500, bdiv = bb*BASE/200 - 128*BASE/200; + //approximations with reasonable precision + adiv = ((5*aa*53687 + (1 << 7)) >> 13) - 128*BASE/500; + bdiv = (( bb*41943 + (1 << 4)) >> 9) - 128*BASE/200+1; + + int ifxz[] = {ify + adiv, ify - bdiv}; + + for(int k = 0; k < 2; k++) + { + int& v = ifxz[k]; + v = abToXZ_b[v-minABvalue]; + } + xx = ifxz[0]; /* yy = yy */; zz = ifxz[1]; + + ro = CV_DESCALE(coeffs[0]*xx + coeffs[1]*yy + coeffs[2]*zz, shift); + go = CV_DESCALE(coeffs[3]*xx + coeffs[4]*yy + coeffs[5]*zz, shift); + bo = CV_DESCALE(coeffs[6]*xx + coeffs[7]*yy + coeffs[8]*zz, shift); + + ro = max(0, min((int)INV_GAMMA_TAB_SIZE-1, ro)); + go = max(0, min((int)INV_GAMMA_TAB_SIZE-1, go)); + bo = max(0, min((int)INV_GAMMA_TAB_SIZE-1, bo)); + + ro = tab[ro]; + go = tab[go]; + bo = tab[bo]; + + dst_row[x*cn ] = saturate_cast(bo); + dst_row[x*cn + 1] = saturate_cast(go); + dst_row[x*cn + 2] = saturate_cast(ro); + if(cn == 4) dst_row[x*cn + 3] = 255; + } + + return n; +} + +int row8uLabChoose(const uchar* src_row, uchar *dst_row, int n, bool forward, int blue_idx, bool srgb) +{ + if(forward) + return row8uRGB2Lab(src_row, dst_row, n, 3, blue_idx, srgb); + else + return row8uLab2RGB(src_row, dst_row, n, 3, blue_idx, srgb); +} + + +TEST(Imgproc_ColorLab_Full, bitExactness) +{ + int codes[] = { CV_BGR2Lab, CV_RGB2Lab, CV_LBGR2Lab, CV_LRGB2Lab, + CV_Lab2BGR, CV_Lab2RGB, CV_Lab2LBGR, CV_Lab2LRGB}; + string names[] = { "CV_BGR2Lab", "CV_RGB2Lab", "CV_LBGR2Lab", "CV_LRGB2Lab", + "CV_Lab2BGR", "CV_Lab2RGB", "CV_Lab2LBGR", "CV_Lab2LRGB" }; + + // need to be recalculated each time we change Lab algorithms, RNG or test system + const int nIterations = 8; + uint32_t hashes[] = { + 0xca7d94c4, 0x34aeb79a, 0x7272c2cf, 0x62c2efed, 0x047cab77, 0x5e8dfb85, 0x10fed613, 0x34d2f4aa, + 0x048bea9a, 0xbbe20ef2, 0x3274e88f, 0x710e9272, 0x9fd6cd59, 0x69d67639, 0x04742095, 0x9ef2b60b, + 0x75b78f5b, 0x3fda9801, 0x374cc472, 0x3239e8ad, 0x94749b2d, 0x9362ac0c, 0xa4d7dd36, 0xe25ef694, + 0x51d1b01d, 0xb0f6e3f5, 0x2b72a228, 0xb7429fa0, 0x799ba6bd, 0x2141d3d2, 0xb4dde471, 0x813b6e0f, + 0x9c029161, 0xb51eb5ec, 0x460c3a09, 0x27724f63, 0xb446c9a8, 0x3adf1b61, 0xe6b0d30f, 0xd1078779, + 0xfaa7525b, 0x5b6ea158, 0xdf3511f7, 0xf01dc02d, 0x5c663841, 0xce611ed4, 0x758ad851, 0xa43c3a1c, + 0xed30f68c, 0xcb6babd9, 0xf38262b5, 0x608cb3db, 0x13425e5a, 0x6dc5fdc7, 0x9519090a, 0x87aa73d0, + 0x8e9bf980, 0x46b98728, 0x0064591c, 0x7e1efc9b, 0xf0ec2465, 0x89a75c8d, 0x0d162fa7, 0xffea7a2f, + }; + + RNG rng(0); + // blueIdx x srgb x direction + for(int c = 0; c < 8; c++) + { + int v = c; + int blueIdx = (v % 2 != 0) ? 2 : 0; v /=2; + bool srgb = (v % 2 == 0); v /= 2; + bool forward = (v % 2 == 0); + + for(int iter = 0; iter < nIterations; iter++) + { + Mat probe(256, 256, CV_8UC3), result; + rng.fill(probe, RNG::UNIFORM, 0, 255, true); + + cvtColor(probe, result, codes[c]); + + uint32_t h = adler32(result); + + if(h != hashes[c*nIterations + iter]) + { + initLabTabs(); + cvtest::TS* ts = cvtest::TS::ptr(); + + vector goldBuf(probe.cols*4); + uchar* goldRow = &goldBuf[0]; + bool next = true; + for(int y = 0; next && y < probe.rows; y++) + { + uchar* probeRow = probe.ptr(y); + uchar* resultRow = result.ptr(y); + row8uLabChoose(probeRow, goldRow, probe.cols, forward, blueIdx, srgb); + + for(int x = 0; next && x < probe.cols; x++) + { + uchar* px = probeRow + x*3; + uchar* gx = goldRow + x*3; + uchar* rx = resultRow + x*3; + if(gx[0] != rx[0] || gx[1] != rx[1] || gx[2] != rx[2]) + { + next = false; + ts->printf(cvtest::TS::SUMMARY, "Error in: (%d, %d)\n", x, y); + ts->printf(cvtest::TS::SUMMARY, "Conversion code: %s\n", names[c].c_str()); + ts->printf(cvtest::TS::SUMMARY, "Reference value: %d %d %d\n", gx[0], gx[1], gx[2]); + ts->printf(cvtest::TS::SUMMARY, "Actual value: %d %d %d\n", rx[0], rx[1], rx[2]); + ts->printf(cvtest::TS::SUMMARY, "Src value: %d %d %d\n", px[0], px[1], px[2]); + ts->printf(cvtest::TS::SUMMARY, "Size: (%d, %d)\n", probe.rows, probe.cols); + + ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY); + ts->set_gtest_status(); + break; + } + } + } + if(next) + // this place should never be reached + throw std::runtime_error("Test system error: hash function mismatch when results are the same"); + } + } + } +} + static void test_Bayer2RGB_EdgeAware_8u(const Mat& src, Mat& dst, int code) { if (dst.empty()) -- 2.7.4