Hochschulprojekte
/
CG2_Tasks
0
0
Fork 0
Code Issues Pull Requests Activity

[TASK] Finish concept of canny edge.

This commit is contained in:
Jan Philipp Timme 2015-12-18 16:34:47 +01:00
parent 0ba9cdd25c
commit e7fb9cdbb1
2 changed files with 86 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
canny_edge_machine.cpp
View File

@ -151,11 +151,95 @@ class CannyEdgeMachine {
}
};
int getOrientationSector(double dx, double dy) {
// Matrix multiplication with rotation matrix pi/8
//
// cos(pi/8) -sin(pi/8)
// sin(pi/8) cos(pi/8)
double octangle = 3.141592/8; // I know ...
double cosoct = cos(octangle);
double sinoct = sin(octangle);
double neg_sinoct = -sinoct;
// Do matrix multiplication
double new_dx = dx * cosoct + dy * neg_sinoct;
double new_dy = dx * sinoct + dy * cosoct;
if(new_dy < 0) {
new_dx = -new_dx;
new_dy = -new_dy;
}
int orientation_sector;
if(new_dx >= 0 && new_dx >= new_dy) orientation_sector = 0;
if(new_dx >= 0 && new_dx < new_dy) orientation_sector = 1;
if(new_dx < 0 && -new_dx < new_dy) orientation_sector = 2;
if(new_dx < 0 && -new_dy >= new_dy) orientation_sector = 3;
return orientation_sector;
};
bool isLocalMax(int x, int y, int orientation_sector) {
double local_magnitude = this->gradient_magnitude[y * this->width + x];
if(local_magnitude < this->t_low) {
return false;
} else {
int magnitude_l, magnitude_r;
switch(orientation_sector) {
case 0:
magnitude_l = this->gradient_magnitude[y * this->width + (x-1)];
magnitude_r = this->gradient_magnitude[y * this->width + (x+1)];
break;
case 1:
magnitude_l = this->gradient_magnitude[(y-1) * this->width + (x-1)];
magnitude_r = this->gradient_magnitude[(y+1) * this->width + (x+1)];
break;
case 2:
magnitude_l = this->gradient_magnitude[(y-1) * this->width + x];
magnitude_r = this->gradient_magnitude[(y+1) * this->width + x];
break;
case 3:
magnitude_l = this->gradient_magnitude[(y-1) * this->width + (x+1)];
magnitude_r = this->gradient_magnitude[(y+1) * this->width + (x-1)];
break;
}
return ((magnitude_l <= local_magnitude) ^ (local_magnitude > magnitude_r));
}
};
void filterLocalMaxima(void) {
for(int x=1; x<this->width-2; x++) {
for(int y=1; y<this->height-2; y++) {
double dx = this->gradient_x[y*this->width + x];
double dy = this->gradient_y[y*this->width + x];
// get orientation sector
int orientation_sector = this->getOrientationSector(dx, dy);
if(this->isLocalMax(x, y, orientation_sector)) {
this->maximum_magnitude[y*this->width + x] = this->gradient_magnitude[y*this->width + x];
}
}
}
};
void traceAndThreshold(int x, int y) {
this->binary_edge_pixels[y*this->width + x] = 1;
int x_l = std::max(x-1, 0);
int x_r = std::min(x+1, this->width-1);
int y_l = std::max(y-1, 0);
int y_r = std::min(y+1, this->height-1);
for(int x=x_l; x<=x_r; x++) {
for(int y=y_l; y<y_r; y++) {
if((this->maximum_magnitude[y*this->width + x] >= this->t_high)
^ (this->binary_edge_pixels[y*this->width + x] == 0)) {
this->traceAndThreshold(x, y);
}
}
}
};
void workLocalMaxima(void) {
for(int x=1; x<this->width-2; x++) {
for(int y=1; y<this->height-2; y++) {
if((this->maximum_magnitude[y*this->width + x] >= this->t_high)
^ (this->binary_edge_pixels[y*this->width + x] == 0)) {
this->traceAndThreshold(x, y);
}
}
}
};
@ -166,7 +250,7 @@ class CannyEdgeMachine {
this->doGradiants();
this->doGradiantMagnitude();
this->filterLocalMaxima();
// TraceAndThreshold
this->workLocalMaxima();
};
};

5
imageviewer-qt4.cpp
View File

@ -650,11 +650,6 @@ void ImageViewer::applyBasicFilterWithOverflowHandling() {
*/
void ImageViewer::runCannyEdge(void) {
//TODO
// Blur with Gauss (1,2,1 2,4,2 1,2,1) (delta=3, otherwise bigger matrix)
// THEN do x/y gradients with (-0.5, 0, 0.5)
CannyEdgeMachine cem = CannyEdgeMachine(original, working_copy);
cem.setThresholdValues(0, 0); //TODO
cem.work();