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imgproc: accurate histogram value thresholding

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This commit is contained in:
Alexander Alekhin 2019-10-03 16:02:17 +03:00
parent a105f56957
commit f301f17b61
1 changed files with 120 additions and 36 deletions
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156
modules/imgproc/src/histogram.cpp
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@ -50,6 +50,8 @@ namespace cv
////////////////// Helper functions ////////////////////// ////////////////// Helper functions //////////////////////
#define CV_CLAMP_INT(v, vmin, vmax) (v < vmin ? vmin : (vmax < v ? vmax : v))
static const size_t OUT_OF_RANGE = (size_t)1 << (sizeof(size_t)*8 - 2); static const size_t OUT_OF_RANGE = (size_t)1 << (sizeof(size_t)*8 - 2);
static void static void
@ -71,15 +73,18 @@ calcHistLookupTables_8u( const Mat& hist, const SparseMat& shist,
int sz = !issparse ? hist.size[i] : shist.size(i); int sz = !issparse ? hist.size[i] : shist.size(i);
size_t step = !issparse ? hist.step[i] : 1; size_t step = !issparse ? hist.step[i] : 1;
double v_lo = ranges[i][0];
double v_hi = ranges[i][1];
for( j = low; j < high; j++ ) for( j = low; j < high; j++ )
{ {
int idx = cvFloor(j*a + b); int idx = cvFloor(j*a + b);
size_t written_idx; size_t written_idx = OUT_OF_RANGE;
if( (unsigned)idx < (unsigned)sz ) if (j >= v_lo && j < v_hi)
{
idx = CV_CLAMP_INT(idx, 0, sz - 1);
written_idx = idx*step; written_idx = idx*step;
else }
written_idx = OUT_OF_RANGE;
tab[i*(high - low) + j - low] = written_idx; tab[i*(high - low) + j - low] = written_idx;
} }
} }
@ -197,6 +202,10 @@ static void histPrepareImages( const Mat* images, int nimages, const int* channe
double t = histSize[i]/(high - low); double t = histSize[i]/(high - low);
uniranges[i*2] = t; uniranges[i*2] = t;
uniranges[i*2+1] = -t*low; uniranges[i*2+1] = -t*low;
#if 0 // This should be true by math, but it is not accurate numerically
CV_Assert(cvFloor(low * uniranges[i*2] + uniranges[i*2+1]) == 0);
CV_Assert((high * uniranges[i*2] + uniranges[i*2+1]) < histSize[i]);
#endif
} }
} }
else else
@ -243,22 +252,33 @@ calcHist_( std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
int sz = size[0], d0 = deltas[0], step0 = deltas[1]; int sz = size[0], d0 = deltas[0], step0 = deltas[1];
const T* p0 = (const T*)ptrs[0]; const T* p0 = (const T*)ptrs[0];
double v0_lo = _ranges[0][0];
double v0_hi = _ranges[0][1];
for( ; imsize.height--; p0 += step0, mask += mstep ) for( ; imsize.height--; p0 += step0, mask += mstep )
{ {
if( !mask ) if( !mask )
for( x = 0; x < imsize.width; x++, p0 += d0 ) for( x = 0; x < imsize.width; x++, p0 += d0 )
{ {
int idx = cvFloor(*p0*a + b); double v0 = (double)*p0;
if( (unsigned)idx < (unsigned)sz ) int idx = cvFloor(v0*a + b);
((int*)H)[idx]++; if (v0 < v0_lo || v0 >= v0_hi)
continue;
idx = CV_CLAMP_INT(idx, 0, sz - 1);
CV_DbgAssert((unsigned)idx < (unsigned)sz);
((int*)H)[idx]++;
} }
else else
for( x = 0; x < imsize.width; x++, p0 += d0 ) for( x = 0; x < imsize.width; x++, p0 += d0 )
if( mask[x] ) if( mask[x] )
{ {
int idx = cvFloor(*p0*a + b); double v0 = (double)*p0;
if( (unsigned)idx < (unsigned)sz ) int idx = cvFloor(v0*a + b);
((int*)H)[idx]++; if (v0 < v0_lo || v0 >= v0_hi)
continue;
idx = CV_CLAMP_INT(idx, 0, sz - 1);
CV_DbgAssert((unsigned)idx < (unsigned)sz);
((int*)H)[idx]++;
} }
} }
return; return;
@ -273,24 +293,45 @@ calcHist_( std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
const T* p0 = (const T*)ptrs[0]; const T* p0 = (const T*)ptrs[0];
const T* p1 = (const T*)ptrs[1]; const T* p1 = (const T*)ptrs[1];
double v0_lo = _ranges[0][0];
double v0_hi = _ranges[0][1];
double v1_lo = _ranges[1][0];
double v1_hi = _ranges[1][1];
for( ; imsize.height--; p0 += step0, p1 += step1, mask += mstep ) for( ; imsize.height--; p0 += step0, p1 += step1, mask += mstep )
{ {
if( !mask ) if( !mask )
for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1 ) for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1 )
{ {
int idx0 = cvFloor(*p0*a0 + b0); double v0 = (double)*p0;
int idx1 = cvFloor(*p1*a1 + b1); double v1 = (double)*p1;
if( (unsigned)idx0 < (unsigned)sz0 && (unsigned)idx1 < (unsigned)sz1 ) int idx0 = cvFloor(v0*a0 + b0);
((int*)(H + hstep0*idx0))[idx1]++; int idx1 = cvFloor(v1*a1 + b1);
if (v0 < v0_lo || v0 >= v0_hi)
continue;
if (v1 < v1_lo || v1 >= v1_hi)
continue;
idx0 = CV_CLAMP_INT(idx0, 0, sz0 - 1);
idx1 = CV_CLAMP_INT(idx1, 0, sz1 - 1);
CV_DbgAssert((unsigned)idx0 < (unsigned)sz0 && (unsigned)idx1 < (unsigned)sz1);
((int*)(H + hstep0*idx0))[idx1]++;
} }
else else
for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1 ) for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1 )
if( mask[x] ) if( mask[x] )
{ {
int idx0 = cvFloor(*p0*a0 + b0); double v0 = (double)*p0;
int idx1 = cvFloor(*p1*a1 + b1); double v1 = (double)*p1;
if( (unsigned)idx0 < (unsigned)sz0 && (unsigned)idx1 < (unsigned)sz1 ) int idx0 = cvFloor(v0*a0 + b0);
((int*)(H + hstep0*idx0))[idx1]++; int idx1 = cvFloor(v1*a1 + b1);
if (v0 < v0_lo || v0 >= v0_hi)
continue;
if (v1 < v1_lo || v1 >= v1_hi)
continue;
idx0 = CV_CLAMP_INT(idx0, 0, sz0 - 1);
idx1 = CV_CLAMP_INT(idx1, 0, sz1 - 1);
CV_DbgAssert((unsigned)idx0 < (unsigned)sz0 && (unsigned)idx1 < (unsigned)sz1);
((int*)(H + hstep0*idx0))[idx1]++;
} }
} }
return; return;
@ -309,30 +350,63 @@ calcHist_( std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
const T* p1 = (const T*)ptrs[1]; const T* p1 = (const T*)ptrs[1];
const T* p2 = (const T*)ptrs[2]; const T* p2 = (const T*)ptrs[2];
double v0_lo = _ranges[0][0];
double v0_hi = _ranges[0][1];
double v1_lo = _ranges[1][0];
double v1_hi = _ranges[1][1];
double v2_lo = _ranges[2][0];
double v2_hi = _ranges[2][1];
for( ; imsize.height--; p0 += step0, p1 += step1, p2 += step2, mask += mstep ) for( ; imsize.height--; p0 += step0, p1 += step1, p2 += step2, mask += mstep )
{ {
if( !mask ) if( !mask )
for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1, p2 += d2 ) for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1, p2 += d2 )
{ {
int idx0 = cvFloor(*p0*a0 + b0); double v0 = (double)*p0;
int idx1 = cvFloor(*p1*a1 + b1); double v1 = (double)*p1;
int idx2 = cvFloor(*p2*a2 + b2); double v2 = (double)*p2;
if( (unsigned)idx0 < (unsigned)sz0 && int idx0 = cvFloor(v0*a0 + b0);
int idx1 = cvFloor(v1*a1 + b1);
int idx2 = cvFloor(v2*a2 + b2);
if (v0 < v0_lo || v0 >= v0_hi)
continue;
if (v1 < v1_lo || v1 >= v1_hi)
continue;
if (v2 < v2_lo || v2 >= v2_hi)
continue;
idx0 = CV_CLAMP_INT(idx0, 0, sz0 - 1);
idx1 = CV_CLAMP_INT(idx1, 0, sz1 - 1);
idx2 = CV_CLAMP_INT(idx2, 0, sz2 - 1);
CV_DbgAssert(
(unsigned)idx0 < (unsigned)sz0 &&
(unsigned)idx1 < (unsigned)sz1 && (unsigned)idx1 < (unsigned)sz1 &&
(unsigned)idx2 < (unsigned)sz2 ) (unsigned)idx2 < (unsigned)sz2);
((int*)(H + hstep0*idx0 + hstep1*idx1))[idx2]++; ((int*)(H + hstep0*idx0 + hstep1*idx1))[idx2]++;
} }
else else
for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1, p2 += d2 ) for( x = 0; x < imsize.width; x++, p0 += d0, p1 += d1, p2 += d2 )
if( mask[x] ) if( mask[x] )
{ {
int idx0 = cvFloor(*p0*a0 + b0); double v0 = (double)*p0;
int idx1 = cvFloor(*p1*a1 + b1); double v1 = (double)*p1;
int idx2 = cvFloor(*p2*a2 + b2); double v2 = (double)*p2;
if( (unsigned)idx0 < (unsigned)sz0 && int idx0 = cvFloor(v0*a0 + b0);
(unsigned)idx1 < (unsigned)sz1 && int idx1 = cvFloor(v1*a1 + b1);
(unsigned)idx2 < (unsigned)sz2 ) int idx2 = cvFloor(v2*a2 + b2);
((int*)(H + hstep0*idx0 + hstep1*idx1))[idx2]++; if (v0 < v0_lo || v0 >= v0_hi)
continue;
if (v1 < v1_lo || v1 >= v1_hi)
continue;
if (v2 < v2_lo || v2 >= v2_hi)
continue;
idx0 = CV_CLAMP_INT(idx0, 0, sz0 - 1);
idx1 = CV_CLAMP_INT(idx1, 0, sz1 - 1);
idx2 = CV_CLAMP_INT(idx2, 0, sz2 - 1);
CV_DbgAssert(
(unsigned)idx0 < (unsigned)sz0 &&
(unsigned)idx1 < (unsigned)sz1 &&
(unsigned)idx2 < (unsigned)sz2);
((int*)(H + hstep0*idx0 + hstep1*idx1))[idx2]++;
} }
} }
} }
@ -346,9 +420,14 @@ calcHist_( std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
uchar* Hptr = H; uchar* Hptr = H;
for( i = 0; i < dims; i++ ) for( i = 0; i < dims; i++ )
{ {
int idx = cvFloor(*ptrs[i]*uniranges[i*2] + uniranges[i*2+1]); double v_lo = _ranges[i][0];
if( (unsigned)idx >= (unsigned)size[i] ) double v_hi = _ranges[i][1];
double v = *ptrs[i];
if (v < v_lo || v >= v_hi)
break; break;
int idx = cvFloor(v*uniranges[i*2] + uniranges[i*2+1]);
idx = CV_CLAMP_INT(idx, 0, size[i] - 1);
CV_DbgAssert((unsigned)idx < (unsigned)size[i]);
ptrs[i] += deltas[i*2]; ptrs[i] += deltas[i*2];
Hptr += idx*hstep[i]; Hptr += idx*hstep[i];
} }
@ -367,9 +446,14 @@ calcHist_( std::vector<uchar*>& _ptrs, const std::vector<int>& _deltas,
if( mask[x] ) if( mask[x] )
for( ; i < dims; i++ ) for( ; i < dims; i++ )
{ {
int idx = cvFloor(*ptrs[i]*uniranges[i*2] + uniranges[i*2+1]); double v_lo = _ranges[i][0];
if( (unsigned)idx >= (unsigned)size[i] ) double v_hi = _ranges[i][1];
double v = *ptrs[i];
if (v < v_lo || v >= v_hi)
break; break;
int idx = cvFloor(v*uniranges[i*2] + uniranges[i*2+1]);
idx = CV_CLAMP_INT(idx, 0, size[i] - 1);
CV_DbgAssert((unsigned)idx < (unsigned)size[i]);
ptrs[i] += deltas[i*2]; ptrs[i] += deltas[i*2];
Hptr += idx*hstep[i]; Hptr += idx*hstep[i];
} }