// GUI calls this function when button "Clear" is pressed, or when new image is loaded
void reset_segm()
{
cout << "resetting 'contour' and 'region'" << endl;
// removing all region markings
region.reset(im.getWidth(),im.getHeight(),0);
// add your code below to remove all points from the "contour"
while(!contour.isEmpty())
contour.popBack();
closedContour = false;
}
// GUI calls this function when button "Clear" is pressed, or when new image is loaded
// THIS FUNCTION IS FULLY IMPLEMENTED, YOU DO NOT NEED TO CHANGE THE CODE IN IT
void reset_segm()
{
cout << "resetting 'contour' and 'region'" << endl;
// removing all region markings
region.reset(image.getWidth(),image.getHeight(),0);
// remove all points from the "contour"
while (!contour.isEmpty()) contour.popBack();
closedContour=false;
// resetting 2D tables "dist" and "toParent" (erazing paths)
dist.reset(image.getWidth(),image.getHeight(),INFTY);
toParent.reset(image.getWidth(),image.getHeight(),NONE);
// recomputing "penalties" from an estimate of image contrast at each pixel p=(x,y)
if (image.isEmpty()) {penalty.resize(0,0); return;}
Table2D<double> contrast = grad2(image); //(implicit conversion of RGB "image" to "Table2D<double>")
// NOTE: function grad2() (see Math2D.h) computes (at each pixel) expression Ix*Ix+Iy*Iy where Ix and Iy
// are "horizontal" and "vertical" derivatives of image intensity I(x,y) - the average of RGB values.
// This expression describes the "rate of change" of intensity, or local image "contrast".
penalty = convert(contrast,&fn); // "&fn" - address of function "fn" (defined at the top of this file)
// "convert" (see Math2D.h) sets penalty at each pixel according to formula "penalty[x][y] = fn (contrast[x][y])"
}
// This function is called at the end of "addToContourLast()". Function
// "contourInterior()" returns volume of the closed contour's interior region
// (including points on the contor itself), or -1 if contour is not closed yet.
// HINT: live-wire() adds to the contour "water-tight" paths of neighboring pixels
int contourInterior()
{
if (!closedContour || image.isEmpty()) return -1;
int counter = 0;
// write your code for computing correct mask (region)
// which should have 3 for pixels OUTSIDE the contour and 0
// for pixels INSIDE of the contour
// HINT: "grow" the "exterior region" from a single exterior point (e.g. a corner of the image).
// Make sure that the region does not grow across the contour (points in list "contour")
// ...
Queue<Point> active;
Point q(1,1);
active.enqueue(q);
region.reset(0);
for (unsigned i=1; i<=contour.getLength(); i++)
region[contour.retrieve(i)]=2;
while (!active.isEmpty())
{
Point p = active.dequeue();
region[p]=3;
counter++;
for (int i=0; i<4; i++)
{
Point j = p + shift[i];
if (image.pointIn(j) && region[j]!=2 && region[j]!=3)
{
active.enqueue(j);
region[j]=3;
}
}
if (view && counter%60==0) {draw(); Pause(20);}
}
for (unsigned i=1; i<=contour.getLength(); i++)
region[contour.retrieve(i)]=0;
return region.getWidth() * region.getHeight() - counter;
}
///////////////////////////////////////////////////////////////////////////////////
// computePaths() is a function for "precomputing" live-wire (shortest) paths from
// any image pixel to the given "seed". This method is called inside "addToContour"
// for each new mouse click. Optimal path from any pixel to the "seed" should accumulate
// the least amount of "penalties" along the path (each pixel p=(x,y) on a path contributes
// penalty[p] precomputed in "reset_segm()"). In this function you should use 2D tables
// "toParent" and "dist" that store for each pixel its "path-towards-seed" direction and,
// correspondingly, the sum of penalties on that path (a.k.a. "distance" to the seed).
// The function iteratively improves paths by traversing pixels from the seed until
// all nodes have direction "toParent" giving the shortest (cheapest) path to the "seed".
void computePaths(Point seed)
{
if (!image.pointIn(seed)) return;
region.reset(0); // resets 2D table "region" for visualization
// Reset 2D arrays "dist" and "toParent" (erazing all current paths)
dist.reset(INFTY);
toParent.reset(NONE);
dist[seed] = 0;
int counter = 0; // just for info printed at the bottom of the function
// THE CODE BELOW GENERATES 2d TABLE toParent WITH PATHS BASED ON !!!!!!!!
// BASIC BREDTH-FIRST_SEARCH TRAVERSAL FROM THE SEED. REPLACE THIS CODE !!!!!!!!
// SO THAT toParent CONTAINS PATHS FOLLOWING HIGH CONSTAST IMAGE BOUNDARIES !!!!!!!!
//
// Create a queue (or priority_queue) for "active" points/pixels and
// traverse pixels to improve paths stored in "toParent" (and "dist")
// .....
Queue<Point> active;
active.enqueue(seed);
while(!active.isEmpty())
{
Point p = active.dequeue();
region[p]=1;
counter++;
for (int i=0; i<4; i++)
{
Point q = p+shift[i]; //using overloaded operator+ for Points (see "Basic2D.h")
double t = dist[p] + penalty[p];
if (image.pointIn(q) && t<dist[q])
{
dist[q]=t;
toParent[q]=Reverse[i];
region[q]=2; // to visualize pixels added to the queue
active.enqueue(q);
}
}
if (view && counter%60==0) {draw(); Pause(20);} // visualization, skipped if checkbox "view" is off
}
// MY PRIORITY QUEUE METHOD WORKS IN THE SAME FASHION AS THE DEMO
// IT IS SLOWER THAN MY QUEUE METHOD, BUT I AM UNSURE IF THIS IS
// AN ISSUE WITH RELEASE MODE COMPARED TO DEBUG MODE
// COMMENT OUT THE ABOVE QUEUE METHOD AND UNCOMMENT THE BELOW METHOD
// TO TEST FUNCTIONALITY OF PRIORITY QUEUE METHOD
/*priority_queue<MyPoint> active;
MyPoint j(seed, dist[seed]);
active.push(j);
while(!active.empty())
{
Point p = active.top();
active.pop();
region[p]=1;
counter++;
for (int i=0; i<4; i++)
{
Point q = p+shift[i]; //using overloaded operator+ for Points (see "Basic2D.h")
double t = dist[p] + penalty[p];
if (image.pointIn(q) && t<dist[q])
{
dist[q]=t;
toParent[q]=Reverse[i];
region[q]=2; // to visualize pixels added to the queue
MyPoint b(q, dist[q]);
active.push(b);
}
}
if (view && counter%60==0) {draw(); Pause(20);} // visualization, skipped if checkbox "view" is off
}*/
// you can print out the number of times a point was removed from the queue
cout << "paths computed, number of 'pops' = " << counter
<< ", number of pixels = " << (region.getWidth()*region.getHeight()) << endl;
}