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// For Open Source Computer Vision Library
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#include "_cv.h"
static CvStatus CV_STDCALL
icvThresh_8u_C1R( const uchar* src, int src_step, uchar* dst, int dst_step,
CvSize roi, uchar thresh, uchar maxval, int type )
{
int i, j;
uchar tab[256];
switch( type )
{
case CV_THRESH_BINARY:
for( i = 0; i <= thresh; i++ )
tab[i] = 0;
for( ; i < 256; i++ )
tab[i] = maxval;
break;
case CV_THRESH_BINARY_INV:
for( i = 0; i <= thresh; i++ )
tab[i] = maxval;
for( ; i < 256; i++ )
tab[i] = 0;
break;
case CV_THRESH_TRUNC:
for( i = 0; i <= thresh; i++ )
tab[i] = (uchar)i;
for( ; i < 256; i++ )
tab[i] = thresh;
break;
case CV_THRESH_TOZERO:
for( i = 0; i <= thresh; i++ )
tab[i] = 0;
for( ; i < 256; i++ )
tab[i] = (uchar)i;
break;
case CV_THRESH_TOZERO_INV:
for( i = 0; i <= thresh; i++ )
tab[i] = (uchar)i;
for( ; i < 256; i++ )
tab[i] = 0;
break;
default:
return CV_BADFLAG_ERR;
}
for( i = 0; i < roi.height; i++, src += src_step, dst += dst_step )
{
for( j = 0; j <= roi.width - 4; j += 4 )
{
uchar t0 = tab[src[j]];
uchar t1 = tab[src[j+1]];
dst[j] = t0;
dst[j+1] = t1;
t0 = tab[src[j+2]];
t1 = tab[src[j+3]];
dst[j+2] = t0;
dst[j+3] = t1;
}
for( ; j < roi.width; j++ )
dst[j] = tab[src[j]];
}
return CV_NO_ERR;
}
static CvStatus CV_STDCALL
icvThresh_32f_C1R( const float *src, int src_step, float *dst, int dst_step,
CvSize roi, float thresh, float maxval, int type )
{
int i, j;
const int* isrc = (const int*)src;
int* idst = (int*)dst;
Cv32suf v;
int iThresh, iMax;
v.f = thresh; iThresh = CV_TOGGLE_FLT(v.i);
v.f = maxval; iMax = v.i;
src_step /= sizeof(src[0]);
dst_step /= sizeof(dst[0]);
switch( type )
{
case CV_THRESH_BINARY:
for( i = 0; i < roi.height; i++, isrc += src_step, idst += dst_step )
{
for( j = 0; j < roi.width; j++ )
{
int temp = isrc[j];
idst[j] = ((CV_TOGGLE_FLT(temp) <= iThresh) - 1) & iMax;
}
}
break;
case CV_THRESH_BINARY_INV:
for( i = 0; i < roi.height; i++, isrc += src_step, idst += dst_step )
{
for( j = 0; j < roi.width; j++ )
{
int temp = isrc[j];
idst[j] = ((CV_TOGGLE_FLT(temp) > iThresh) - 1) & iMax;
}
}
break;
case CV_THRESH_TRUNC:
for( i = 0; i < roi.height; i++, src += src_step, dst += dst_step )
{
for( j = 0; j < roi.width; j++ )
{
float temp = src[j];
if( temp > thresh )
temp = thresh;
dst[j] = temp;
}
}
break;
case CV_THRESH_TOZERO:
for( i = 0; i < roi.height; i++, isrc += src_step, idst += dst_step )
{
for( j = 0; j < roi.width; j++ )
{
int temp = isrc[j];
idst[j] = ((CV_TOGGLE_FLT( temp ) <= iThresh) - 1) & temp;
}
}
break;
case CV_THRESH_TOZERO_INV:
for( i = 0; i < roi.height; i++, isrc += src_step, idst += dst_step )
{
for( j = 0; j < roi.width; j++ )
{
int temp = isrc[j];
idst[j] = ((CV_TOGGLE_FLT( temp ) > iThresh) - 1) & temp;
}
}
break;
default:
return CV_BADFLAG_ERR;
}
return CV_OK;
}
static double
icvGetThreshVal_Otsu( const CvHistogram* hist )
{
double max_val = 0;
CV_FUNCNAME( "icvGetThreshVal_Otsu" );
__BEGIN__;
int i, count;
const float* h;
double sum = 0, mu = 0;
bool uniform = false;
double low = 0, high = 0, delta = 0;
float* nu_thresh = 0;
double mu1 = 0, q1 = 0;
double max_sigma = 0;
if( !CV_IS_HIST(hist) || CV_IS_SPARSE_HIST(hist) || hist->mat.dims != 1 )
CV_ERROR( CV_StsBadArg,
"The histogram in Otsu method must be a valid dense 1D histogram" );
count = hist->mat.dim[0].size;
h = (float*)cvPtr1D( hist->bins, 0 );
if( !CV_HIST_HAS_RANGES(hist) || CV_IS_UNIFORM_HIST(hist) )
{
if( CV_HIST_HAS_RANGES(hist) )
{
low = hist->thresh[0][0];
high = hist->thresh[0][1];
}
else
{
low = 0;
high = count;
}
delta = (high-low)/count;
low += delta*0.5;
uniform = true;
}
else
nu_thresh = hist->thresh2[0];
for( i = 0; i < count; i++ )
{
sum += h[i];
if( uniform )
mu += (i*delta + low)*h[i];
else
mu += (nu_thresh[i*2] + nu_thresh[i*2+1])*0.5*h[i];
}
sum = fabs(sum) > FLT_EPSILON ? 1./sum : 0;
mu *= sum;
mu1 = 0;
q1 = 0;
for( i = 0; i < count; i++ )
{
double p_i, q2, mu2, val_i, sigma;
p_i = h[i]*sum;
mu1 *= q1;
q1 += p_i;
q2 = 1. - q1;
if( MIN(q1,q2) < FLT_EPSILON || MAX(q1,q2) > 1. - FLT_EPSILON )
continue;
if( uniform )
val_i = i*delta + low;
else
val_i = (nu_thresh[i*2] + nu_thresh[i*2+1])*0.5;
mu1 = (mu1 + val_i*p_i)/q1;
mu2 = (mu - q1*mu1)/q2;
sigma = q1*q2*(mu1 - mu2)*(mu1 - mu2);
if( sigma > max_sigma )
{
max_sigma = sigma;
max_val = val_i;
}
}
__END__;
return max_val;
}
icvAndC_8u_C1R_t icvAndC_8u_C1R_p = 0;
icvCompareC_8u_C1R_cv_t icvCompareC_8u_C1R_cv_p = 0;
icvThreshold_GTVal_8u_C1R_t icvThreshold_GTVal_8u_C1R_p = 0;
icvThreshold_GTVal_32f_C1R_t icvThreshold_GTVal_32f_C1R_p = 0;
icvThreshold_LTVal_8u_C1R_t icvThreshold_LTVal_8u_C1R_p = 0;
icvThreshold_LTVal_32f_C1R_t icvThreshold_LTVal_32f_C1R_p = 0;
CV_IMPL double
cvThreshold( const void* srcarr, void* dstarr, double thresh, double maxval, int type )
{
CvHistogram* hist = 0;
CV_FUNCNAME( "cvThreshold" );
__BEGIN__;
CvSize roi;
int src_step, dst_step;
CvMat src_stub, *src = (CvMat*)srcarr;
CvMat dst_stub, *dst = (CvMat*)dstarr;
CvMat src0, dst0;
int coi1 = 0, coi2 = 0;
int ithresh, imaxval, cn;
bool use_otsu;
CV_CALL( src = cvGetMat( src, &src_stub, &coi1 ));
CV_CALL( dst = cvGetMat( dst, &dst_stub, &coi2 ));
if( coi1 + coi2 )
CV_ERROR( CV_BadCOI, "COI is not supported by the function" );
if( !CV_ARE_CNS_EQ( src, dst ) )
CV_ERROR( CV_StsUnmatchedFormats, "Both arrays must have equal number of channels" );
cn = CV_MAT_CN(src->type);
if( cn > 1 )
{
src = cvReshape( src, &src0, 1 );
dst = cvReshape( dst, &dst0, 1 );
}
use_otsu = (type & ~CV_THRESH_MASK) == CV_THRESH_OTSU;
type &= CV_THRESH_MASK;
if( use_otsu )
{
float _ranges[] = { 0, 256 };
float* ranges = _ranges;
int hist_size = 256;
void* srcarr0 = src;
if( CV_MAT_TYPE(src->type) != CV_8UC1 )
CV_ERROR( CV_StsNotImplemented, "Otsu method can only be used with 8uC1 images" );
CV_CALL( hist = cvCreateHist( 1, &hist_size, CV_HIST_ARRAY, &ranges ));
cvCalcArrHist( &srcarr0, hist );
thresh = cvFloor(icvGetThreshVal_Otsu( hist ));
}
if( !CV_ARE_DEPTHS_EQ( src, dst ) )
{
if( CV_MAT_TYPE(dst->type) != CV_8UC1 )
CV_ERROR( CV_StsUnsupportedFormat, "In case of different types destination should be 8uC1" );
if( type != CV_THRESH_BINARY && type != CV_THRESH_BINARY_INV )
CV_ERROR( CV_StsBadArg,
"In case of different types only CV_THRESH_BINARY "
"and CV_THRESH_BINARY_INV thresholding types are supported" );
if( maxval < 0 )
{
CV_CALL( cvSetZero( dst ));
}
else
{
CV_CALL( cvCmpS( src, thresh, dst, type == CV_THRESH_BINARY ? CV_CMP_GT : CV_CMP_LE ));
if( maxval < 255 )
CV_CALL( cvAndS( dst, cvScalarAll( maxval ), dst ));
}
EXIT;
}
if( !CV_ARE_SIZES_EQ( src, dst ) )
CV_ERROR( CV_StsUnmatchedSizes, "" );
roi = cvGetMatSize( src );
if( CV_IS_MAT_CONT( src->type & dst->type ))
{
roi.width *= roi.height;
roi.height = 1;
src_step = dst_step = CV_STUB_STEP;
}
else
{
src_step = src->step;
dst_step = dst->step;
}
switch( CV_MAT_DEPTH(src->type) )
{
case CV_8U:
ithresh = cvFloor(thresh);
imaxval = cvRound(maxval);
if( type == CV_THRESH_TRUNC )
imaxval = ithresh;
imaxval = CV_CAST_8U(imaxval);
if( ithresh < 0 || ithresh >= 255 )
{
if( type == CV_THRESH_BINARY || type == CV_THRESH_BINARY_INV ||
((type == CV_THRESH_TRUNC || type == CV_THRESH_TOZERO_INV) && ithresh < 0) ||
(type == CV_THRESH_TOZERO && ithresh >= 255) )
{
int v = type == CV_THRESH_BINARY ? (ithresh >= 255 ? 0 : imaxval) :
type == CV_THRESH_BINARY_INV ? (ithresh >= 255 ? imaxval : 0) :
type == CV_THRESH_TRUNC ? imaxval : 0;
cvSet( dst, cvScalarAll(v) );
EXIT;
}
else
{
cvCopy( src, dst );
EXIT;
}
}
if( type == CV_THRESH_BINARY || type == CV_THRESH_BINARY_INV )
{
if( icvCompareC_8u_C1R_cv_p && icvAndC_8u_C1R_p )
{
IPPI_CALL( icvCompareC_8u_C1R_cv_p( src->data.ptr, src_step,
(uchar)ithresh, dst->data.ptr, dst_step, roi,
type == CV_THRESH_BINARY ? cvCmpGreater : cvCmpLessEq ));
if( imaxval < 255 )
IPPI_CALL( icvAndC_8u_C1R_p( dst->data.ptr, dst_step,
(uchar)imaxval, dst->data.ptr, dst_step, roi ));
EXIT;
}
}
else if( type == CV_THRESH_TRUNC || type == CV_THRESH_TOZERO_INV )
{
if( icvThreshold_GTVal_8u_C1R_p )
{
IPPI_CALL( icvThreshold_GTVal_8u_C1R_p( src->data.ptr, src_step,
dst->data.ptr, dst_step, roi, (uchar)ithresh,
(uchar)(type == CV_THRESH_TRUNC ? ithresh : 0) ));
EXIT;
}
}
else
{
assert( type == CV_THRESH_TOZERO );
if( icvThreshold_LTVal_8u_C1R_p )
{
ithresh = cvFloor(thresh+1.);
ithresh = CV_CAST_8U(ithresh);
IPPI_CALL( icvThreshold_LTVal_8u_C1R_p( src->data.ptr, src_step,
dst->data.ptr, dst_step, roi, (uchar)ithresh, 0 ));
EXIT;
}
}
icvThresh_8u_C1R( src->data.ptr, src_step,
dst->data.ptr, dst_step, roi,
(uchar)ithresh, (uchar)imaxval, type );
break;
case CV_32F:
if( type == CV_THRESH_TRUNC || type == CV_THRESH_TOZERO_INV )
{
if( icvThreshold_GTVal_32f_C1R_p )
{
IPPI_CALL( icvThreshold_GTVal_32f_C1R_p( src->data.fl, src_step,
dst->data.fl, dst_step, roi, (float)thresh,
type == CV_THRESH_TRUNC ? (float)thresh : 0 ));
EXIT;
}
}
else if( type == CV_THRESH_TOZERO )
{
if( icvThreshold_LTVal_32f_C1R_p )
{
IPPI_CALL( icvThreshold_LTVal_32f_C1R_p( src->data.fl, src_step,
dst->data.fl, dst_step, roi, (float)(thresh*(1 + FLT_EPSILON)), 0 ));
EXIT;
}
}
icvThresh_32f_C1R( src->data.fl, src_step, dst->data.fl, dst_step, roi,
(float)thresh, (float)maxval, type );
break;
default:
CV_ERROR( CV_BadDepth, cvUnsupportedFormat );
}
__END__;
if( hist )
cvReleaseHist( &hist );
return thresh;
}
/* End of file. */