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bit-exact tests written for Lab

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This commit is contained in:
Rostislav Vasilikhin 2017-08-15 18:43:55 +03:00
parent 758f914249
commit 375ec5ed7e
1 changed files with 255 additions and 8 deletions
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263
modules/imgproc/test/test_color.cpp
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@ -70,11 +70,11 @@ protected:
// called from default implementation of convert_backward
// for cases of bit-exact functions
virtual int convert_row_abc2bgr_8u_c3( const uchar* src_row, uchar* dst_row, int n );
virtual int convert_row_abc2bgr_8u_c3( const uchar* src_row, uchar* dst_row, int n, int cn );
// called from default implementation of convert_forward
// for cases of bit-exact functions
virtual int convert_row_bgr2abc_8u_c3(const uchar *src_row, uchar *dst_row, int n );
virtual int convert_row_bgr2abc_8u_c3(const uchar *src_row, uchar *dst_row, int n, int cn);
const char* fwd_code_str;
const char* inv_code_str;
@ -237,7 +237,7 @@ void CV_ColorCvtBaseTest::convert_forward( const Mat& src, Mat& dst )
const uchar* src_row = src.ptr(i);
uchar* dst_row = dst.ptr(i);
int processed = convert_row_bgr2abc_8u_c3( src_row, dst_row, cols );
int processed = convert_row_bgr2abc_8u_c3( src_row, dst_row, cols, cn );
if(processed != cols)
{
for( j = 0; j < cols; j++ )
@ -313,14 +313,14 @@ void CV_ColorCvtBaseTest::convert_row_abc2bgr_32f_c3( const float* /*src_row*/,
int CV_ColorCvtBaseTest::convert_row_abc2bgr_8u_c3(const uchar * /*src_row*/,
uchar * /*dst_row*/, int /*n*/ )
uchar * /*dst_row*/, int /*n*/, int /*cn*/ )
{
return 0;
}
int CV_ColorCvtBaseTest::convert_row_bgr2abc_8u_c3( const uchar* /*src_row*/,
uchar* /*dst_row*/, int /*n*/ )
int CV_ColorCvtBaseTest::convert_row_bgr2abc_8u_c3(const uchar* /*src_row*/,
uchar* /*dst_row*/, int /*n*/ , int /*cn*/)
{
return 0;
}
@ -349,7 +349,7 @@ void CV_ColorCvtBaseTest::convert_backward( const Mat& src, const Mat& dst, Mat&
const uchar* src_row = dst.ptr(i);
uchar* dst_row = dst2.ptr(i);
int processed = convert_row_abc2bgr_8u_c3(src_row, dst_row, dst_cols);
int processed = convert_row_abc2bgr_8u_c3(src_row, dst_row, dst_cols, cn);
if(processed != dst_cols)
{
@ -1027,6 +1027,57 @@ void CV_ColorXYZTest::convert_row_abc2bgr_32f_c3( const float* src_row, float* d
//// rgb <=> L*a*b*
// 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<<gamma_shift))
static ushort LabCbrtTab_b[LAB_CBRT_TAB_SIZE_B];
enum
{
lab_base_shift = 14,
LAB_BASE = (1 << lab_base_shift),
};
#define CV_DESCALE(x,n) (((x) + (1 << ((n)-1))) >> (n))
static ushort LabToYF_b[256*2];
static const int minABvalue = -8145;
static int abToXZ_b[LAB_BASE*9/4];
//all constants should be presented through integers to keep bit-exactness
static const softdouble gammaThreshold = softdouble(809)/softdouble(20000); // 0.04045
static const softdouble gammaInvThreshold = softdouble(7827)/softdouble(2500000); // 0.0031308
static const softdouble gammaLowScale = softdouble(323)/softdouble(25); // 12.92
static const softdouble gammaPower = softdouble(12)/softdouble(5); // 2.4
static const softdouble gammaXshift = softdouble(11)/softdouble(200); // 0.055
static inline softfloat applyGamma(softfloat x)
{
//return x <= 0.04045f ? x*(1.f/12.92f) : (float)std::pow((double)(x + 0.055)*(1./1.055), 2.4);
softdouble xd = x;
return (xd <= gammaThreshold ?
xd/gammaLowScale :
pow((xd + gammaXshift)/(softdouble::one()+gammaXshift), gammaPower));
}
static inline softfloat applyInvGamma(softfloat x)
{
//return x <= 0.0031308 ? x*12.92f : (float)(1.055*std::pow((double)x, 1./2.4) - 0.055);
softdouble xd = x;
return (xd <= gammaInvThreshold ?
xd*gammaLowScale :
pow(xd, softdouble::one()/gammaPower)*(softdouble::one()+gammaXshift) - gammaXshift);
}
static inline float applyGamma(float x)
{
return x <= 0.04045f ? x*(1.f/12.92f) : (float)std::pow((double)(x + 0.055)*(1./1.055), 2.4);
@ -1037,6 +1088,90 @@ static inline float applyInvGamma(float x)
return x <= 0.0031308 ? x*12.92f : (float)(1.055*std::pow((double)x, 1./2.4) - 0.055);
}
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;
}
}
class CV_ColorLabTest : public CV_ColorCvtBaseTest
{
public:
@ -1046,11 +1181,14 @@ protected:
double get_success_error_level( int test_case_idx, int i, int j );
void convert_row_bgr2abc_32f_c3( const float* src_row, float* dst_row, int n );
void convert_row_abc2bgr_32f_c3( const float* src_row, float* dst_row, int n );
int convert_row_bgr2abc_8u_c3( const uchar *src_row, uchar *dst_row, int n, int cn );
int convert_row_abc2bgr_8u_c3( const uchar *src_row, uchar *dst_row, int n, int cn );
};
CV_ColorLabTest::CV_ColorLabTest() : CV_ColorCvtBaseTest( true, true, false )
{
initLabTabs();
INIT_FWD_INV_CODES( BGR2Lab, Lab2BGR );
}
@ -1079,7 +1217,50 @@ void CV_ColorLabTest::get_test_array_types_and_sizes( int test_case_idx, vector<
double CV_ColorLabTest::get_success_error_level( int /*test_case_idx*/, int i, int j )
{
int depth = test_mat[i][j].depth();
return depth == CV_8U ? 16 : depth == CV_16U ? 32 : 1e-3;
// j == 0 is for forward code, j == 1 is for inverse code
return (depth == CV_8U) ? 0 :
//16u is forbidden
//(depth == CV_16U) ? 32 :
srgb ? ((j == 0) ? 0.4 : 0.0055) : 1e-3;
}
int CV_ColorLabTest::convert_row_bgr2abc_8u_c3(const uchar* src_row, uchar *dst_row, int n, int cn)
{
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<uchar>(L);
dst_row[x*3 + 1] = saturate_cast<uchar>(a);
dst_row[x*3 + 2] = saturate_cast<uchar>(b);
}
return n;
}
@ -1137,6 +1318,71 @@ void CV_ColorLabTest::convert_row_bgr2abc_32f_c3(const float* src_row, float* ds
}
}
int CV_ColorLabTest::convert_row_abc2bgr_8u_c3(const uchar* src_row, uchar *dst_row, int n, int cn)
{
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<uchar>(bo);
dst_row[x*cn + 1] = saturate_cast<uchar>(go);
dst_row[x*cn + 2] = saturate_cast<uchar>(ro);
if(cn == 4) dst_row[x*cn + 3] = 255;
}
return n;
}
void CV_ColorLabTest::convert_row_abc2bgr_32f_c3( const float* src_row, float* dst_row, int n )
{
int depth = test_mat[INPUT][0].depth();
@ -1226,6 +1472,7 @@ protected:
CV_ColorLuvTest::CV_ColorLuvTest() : CV_ColorCvtBaseTest( true, true, false )
{
initLabTabs();
INIT_FWD_INV_CODES( BGR2Luv, Luv2BGR );
}