opencv/modules/imgproc/src/canny.cpp

350 lines
12 KiB
C++

/*M///////////////////////////////////////////////////////////////////////////////////////
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#include "precomp.hpp"
CV_IMPL void cvCanny( const void* srcarr, void* dstarr,
double low_thresh, double high_thresh,
int aperture_size )
{
cv::Ptr<CvMat> dx, dy;
cv::AutoBuffer<char> buffer;
std::vector<uchar*> stack;
uchar **stack_top = 0, **stack_bottom = 0;
CvMat srcstub, *src = cvGetMat( srcarr, &srcstub );
CvMat dststub, *dst = cvGetMat( dstarr, &dststub );
CvSize size;
int flags = aperture_size;
int low, high;
int* mag_buf[3];
uchar* map;
ptrdiff_t mapstep;
int maxsize;
int i, j;
CvMat mag_row;
if( CV_MAT_TYPE( src->type ) != CV_8UC1 ||
CV_MAT_TYPE( dst->type ) != CV_8UC1 )
CV_Error( CV_StsUnsupportedFormat, "" );
if( !CV_ARE_SIZES_EQ( src, dst ))
CV_Error( CV_StsUnmatchedSizes, "" );
if( low_thresh > high_thresh )
{
double t;
CV_SWAP( low_thresh, high_thresh, t );
}
aperture_size &= INT_MAX;
if( (aperture_size & 1) == 0 || aperture_size < 3 || aperture_size > 7 )
CV_Error( CV_StsBadFlag, "" );
size = cvGetMatSize( src );
dx = cvCreateMat( size.height, size.width, CV_16SC1 );
dy = cvCreateMat( size.height, size.width, CV_16SC1 );
cvSobel( src, dx, 1, 0, aperture_size );
cvSobel( src, dy, 0, 1, aperture_size );
/*if( icvCannyGetSize_p && icvCanny_16s8u_C1R_p && !(flags & CV_CANNY_L2_GRADIENT) )
{
int buf_size= 0;
IPPI_CALL( icvCannyGetSize_p( size, &buf_size ));
CV_CALL( buffer = cvAlloc( buf_size ));
IPPI_CALL( icvCanny_16s8u_C1R_p( (short*)dx->data.ptr, dx->step,
(short*)dy->data.ptr, dy->step,
dst->data.ptr, dst->step,
size, (float)low_thresh,
(float)high_thresh, buffer ));
EXIT;
}*/
if( flags & CV_CANNY_L2_GRADIENT )
{
Cv32suf ul, uh;
ul.f = (float)low_thresh;
uh.f = (float)high_thresh;
low = ul.i;
high = uh.i;
}
else
{
low = cvFloor( low_thresh );
high = cvFloor( high_thresh );
}
buffer.allocate( (size.width+2)*(size.height+2) + (size.width+2)*3*sizeof(int) );
mag_buf[0] = (int*)(char*)buffer;
mag_buf[1] = mag_buf[0] + size.width + 2;
mag_buf[2] = mag_buf[1] + size.width + 2;
map = (uchar*)(mag_buf[2] + size.width + 2);
mapstep = size.width + 2;
maxsize = MAX( 1 << 10, size.width*size.height/10 );
stack.resize( maxsize );
stack_top = stack_bottom = &stack[0];
memset( mag_buf[0], 0, (size.width+2)*sizeof(int) );
memset( map, 1, mapstep );
memset( map + mapstep*(size.height + 1), 1, mapstep );
/* sector numbers
(Top-Left Origin)
1 2 3
* * *
* * *
0*******0
* * *
* * *
3 2 1
*/
#define CANNY_PUSH(d) *(d) = (uchar)2, *stack_top++ = (d)
#define CANNY_POP(d) (d) = *--stack_top
mag_row = cvMat( 1, size.width, CV_32F );
// calculate magnitude and angle of gradient, perform non-maxima supression.
// fill the map with one of the following values:
// 0 - the pixel might belong to an edge
// 1 - the pixel can not belong to an edge
// 2 - the pixel does belong to an edge
for( i = 0; i <= size.height; i++ )
{
int* _mag = mag_buf[(i > 0) + 1] + 1;
float* _magf = (float*)_mag;
const short* _dx = (short*)(dx->data.ptr + dx->step*i);
const short* _dy = (short*)(dy->data.ptr + dy->step*i);
uchar* _map;
int x, y;
ptrdiff_t magstep1, magstep2;
int prev_flag = 0;
if( i < size.height )
{
_mag[-1] = _mag[size.width] = 0;
if( !(flags & CV_CANNY_L2_GRADIENT) )
for( j = 0; j < size.width; j++ )
_mag[j] = abs(_dx[j]) + abs(_dy[j]);
/*else if( icvFilterSobelVert_8u16s_C1R_p != 0 ) // check for IPP
{
// use vectorized sqrt
mag_row.data.fl = _magf;
for( j = 0; j < size.width; j++ )
{
x = _dx[j]; y = _dy[j];
_magf[j] = (float)((double)x*x + (double)y*y);
}
cvPow( &mag_row, &mag_row, 0.5 );
}*/
else
{
for( j = 0; j < size.width; j++ )
{
x = _dx[j]; y = _dy[j];
_magf[j] = (float)std::sqrt((double)x*x + (double)y*y);
}
}
}
else
memset( _mag-1, 0, (size.width + 2)*sizeof(int) );
// at the very beginning we do not have a complete ring
// buffer of 3 magnitude rows for non-maxima suppression
if( i == 0 )
continue;
_map = map + mapstep*i + 1;
_map[-1] = _map[size.width] = 1;
_mag = mag_buf[1] + 1; // take the central row
_dx = (short*)(dx->data.ptr + dx->step*(i-1));
_dy = (short*)(dy->data.ptr + dy->step*(i-1));
magstep1 = mag_buf[2] - mag_buf[1];
magstep2 = mag_buf[0] - mag_buf[1];
if( (stack_top - stack_bottom) + size.width > maxsize )
{
int sz = (int)(stack_top - stack_bottom);
maxsize = MAX( maxsize * 3/2, maxsize + 8 );
stack.resize(maxsize);
stack_bottom = &stack[0];
stack_top = stack_bottom + sz;
}
for( j = 0; j < size.width; j++ )
{
#define CANNY_SHIFT 15
#define TG22 (int)(0.4142135623730950488016887242097*(1<<CANNY_SHIFT) + 0.5)
x = _dx[j];
y = _dy[j];
int s = x ^ y;
int m = _mag[j];
x = abs(x);
y = abs(y);
if( m > low )
{
int tg22x = x * TG22;
int tg67x = tg22x + ((x + x) << CANNY_SHIFT);
y <<= CANNY_SHIFT;
if( y < tg22x )
{
if( m > _mag[j-1] && m >= _mag[j+1] )
{
if( m > high && !prev_flag && _map[j-mapstep] != 2 )
{
CANNY_PUSH( _map + j );
prev_flag = 1;
}
else
_map[j] = (uchar)0;
continue;
}
}
else if( y > tg67x )
{
if( m > _mag[j+magstep2] && m >= _mag[j+magstep1] )
{
if( m > high && !prev_flag && _map[j-mapstep] != 2 )
{
CANNY_PUSH( _map + j );
prev_flag = 1;
}
else
_map[j] = (uchar)0;
continue;
}
}
else
{
s = s < 0 ? -1 : 1;
if( m > _mag[j+magstep2-s] && m > _mag[j+magstep1+s] )
{
if( m > high && !prev_flag && _map[j-mapstep] != 2 )
{
CANNY_PUSH( _map + j );
prev_flag = 1;
}
else
_map[j] = (uchar)0;
continue;
}
}
}
prev_flag = 0;
_map[j] = (uchar)1;
}
// scroll the ring buffer
_mag = mag_buf[0];
mag_buf[0] = mag_buf[1];
mag_buf[1] = mag_buf[2];
mag_buf[2] = _mag;
}
// now track the edges (hysteresis thresholding)
while( stack_top > stack_bottom )
{
uchar* m;
if( (stack_top - stack_bottom) + 8 > maxsize )
{
int sz = (int)(stack_top - stack_bottom);
maxsize = MAX( maxsize * 3/2, maxsize + 8 );
stack.resize(maxsize);
stack_bottom = &stack[0];
stack_top = stack_bottom + sz;
}
CANNY_POP(m);
if( !m[-1] )
CANNY_PUSH( m - 1 );
if( !m[1] )
CANNY_PUSH( m + 1 );
if( !m[-mapstep-1] )
CANNY_PUSH( m - mapstep - 1 );
if( !m[-mapstep] )
CANNY_PUSH( m - mapstep );
if( !m[-mapstep+1] )
CANNY_PUSH( m - mapstep + 1 );
if( !m[mapstep-1] )
CANNY_PUSH( m + mapstep - 1 );
if( !m[mapstep] )
CANNY_PUSH( m + mapstep );
if( !m[mapstep+1] )
CANNY_PUSH( m + mapstep + 1 );
}
// the final pass, form the final image
for( i = 0; i < size.height; i++ )
{
const uchar* _map = map + mapstep*(i+1) + 1;
uchar* _dst = dst->data.ptr + dst->step*i;
for( j = 0; j < size.width; j++ )
_dst[j] = (uchar)-(_map[j] >> 1);
}
}
void cv::Canny( InputArray image, OutputArray _edges,
double threshold1, double threshold2,
int apertureSize, bool L2gradient )
{
Mat src = image.getMat();
_edges.create(src.size(), CV_8U);
CvMat c_src = src, c_dst = _edges.getMat();
cvCanny( &c_src, &c_dst, threshold1, threshold2,
apertureSize + (L2gradient ? CV_CANNY_L2_GRADIENT : 0));
}
/* End of file. */