opencv/modules/stitching/seam_finders.cpp

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2011-05-04 13:09:42 +02:00
#include <opencv2/imgproc/imgproc.hpp>
#include <gcgraph.hpp>
#include "seam_finders.hpp"
#include "util.hpp"
using namespace std;
using namespace cv;
Ptr<SeamFinder> SeamFinder::createDefault(int type)
{
if (type == NO)
return new NoSeamFinder();
if (type == VORONOI)
return new VoronoiSeamFinder();
if (type == GRAPH_CUT)
return new GraphCutSeamFinder();
CV_Error(CV_StsBadArg, "unsupported seam finding method");
return NULL;
}
void PairwiseSeamFinder::find(const vector<Mat> &src, const vector<Point> &corners,
vector<Mat> &masks)
{
if (src.size() == 0)
return;
for (size_t i = 0; i < src.size() - 1; ++i)
{
for (size_t j = i + 1; j < src.size(); ++j)
{
int x_min = max(corners[i].x, corners[j].x);
int x_max = min(corners[i].x + src[i].cols - 1, corners[j].x + src[j].cols - 1);
int y_min = max(corners[i].y, corners[j].y);
int y_max = min(corners[i].y + src[i].rows - 1, corners[j].y + src[j].rows - 1);
if (x_max >= x_min && y_max >= y_min)
findInPair(src[i], src[j], corners[i], corners[j],
Rect(x_min, y_min, x_max - x_min + 1, y_max - y_min + 1),
masks[i], masks[j]);
}
}
}
void VoronoiSeamFinder::findInPair(const Mat &img1, const Mat &img2, Point tl1, Point tl2,
Rect roi, Mat &mask1, Mat &mask2)
{
const int gap = 10;
Mat submask1(roi.height + 2 * gap, roi.width + 2 * gap, CV_8U);
Mat submask2(roi.height + 2 * gap, roi.width + 2 * gap, CV_8U);
// Cut submasks with some gap
for (int y = -gap; y < roi.height + gap; ++y)
{
for (int x = -gap; x < roi.width + gap; ++x)
{
int y1 = roi.y - tl1.y + y;
int x1 = roi.x - tl1.x + x;
if (y1 >= 0 && x1 >= 0 && y1 < img1.rows && x1 < img1.cols)
submask1.at<uchar>(y + gap, x + gap) = mask1.at<uchar>(y1, x1);
else
submask1.at<uchar>(y + gap, x + gap) = 0;
int y2 = roi.y - tl2.y + y;
int x2 = roi.x - tl2.x + x;
if (y2 >= 0 && x2 >= 0 && y2 < img2.rows && x2 < img2.cols)
submask2.at<uchar>(y + gap, x + gap) = mask2.at<uchar>(y2, x2);
else
submask2.at<uchar>(y + gap, x + gap) = 0;
}
}
Mat collision = (submask1 != 0) & (submask2 != 0);
Mat unique1 = submask1.clone(); unique1.setTo(0, collision);
Mat unique2 = submask2.clone(); unique2.setTo(0, collision);
Mat dist1, dist2;
distanceTransform(unique1 == 0, dist1, CV_DIST_L1, 3);
distanceTransform(unique2 == 0, dist2, CV_DIST_L1, 3);
Mat seam = dist1 < dist2;
for (int y = 0; y < roi.height; ++y)
{
for (int x = 0; x < roi.width; ++x)
{
if (seam.at<uchar>(y + gap, x + gap))
mask2.at<uchar>(roi.y - tl2.y + y, roi.x - tl2.x + x) = 0;
else
mask1.at<uchar>(roi.y - tl1.y + y, roi.x - tl1.x + x) = 0;
}
}
}
class GraphCutSeamFinder::Impl
{
public:
Impl(int cost_type, float terminal_cost, float bad_region_penalty)
: cost_type_(cost_type), terminal_cost_(terminal_cost), bad_region_penalty_(bad_region_penalty) {}
void findInPair(const Mat &img1, const Mat &img2, Point tl1, Point tl2,
Rect roi, Mat &mask1, Mat &mask2);
private:
void setGraphWeightsColor(const Mat &img1, const Mat &img2, const Mat &mask1, const Mat &mask2,
GCGraph<float> &graph);
int cost_type_;
float terminal_cost_;
float bad_region_penalty_;
};
void GraphCutSeamFinder::Impl::setGraphWeightsColor(const Mat &img1, const Mat &img2, const Mat &mask1, const Mat &mask2,
GCGraph<float> &graph)
{
const Size img_size = img1.size();
// Set terminal weights
for (int y = 0; y < img_size.height; ++y)
{
for (int x = 0; x < img_size.width; ++x)
{
int v = graph.addVtx();
graph.addTermWeights(v, mask1.at<uchar>(y, x) ? terminal_cost_ : 0.f,
mask2.at<uchar>(y, x) ? terminal_cost_ : 0.f);
}
}
const float weight_eps = 1e-3f;
// Set regular edge weights
for (int y = 0; y < img_size.height; ++y)
{
for (int x = 0; x < img_size.width; ++x)
{
int v = y * img_size.width + x;
if (x < img_size.width - 1)
{
float weight = normL2(img1.at<Point3f>(y, x), img2.at<Point3f>(y, x)) +
normL2(img1.at<Point3f>(y, x + 1), img2.at<Point3f>(y, x + 1)) +
weight_eps;
if (!mask1.at<uchar>(y, x) || !mask1.at<uchar>(y, x + 1) ||
!mask2.at<uchar>(y, x) || !mask2.at<uchar>(y, x + 1))
weight += bad_region_penalty_;
graph.addEdges(v, v + 1, weight, weight);
}
if (y < img_size.height - 1)
{
float weight = normL2(img1.at<Point3f>(y, x), img2.at<Point3f>(y, x)) +
normL2(img1.at<Point3f>(y + 1, x), img2.at<Point3f>(y + 1, x)) +
weight_eps;
if (!mask1.at<uchar>(y, x) || !mask1.at<uchar>(y + 1, x) ||
!mask2.at<uchar>(y, x) || !mask2.at<uchar>(y + 1, x))
weight += bad_region_penalty_;
graph.addEdges(v, v + img_size.width, weight, weight);
}
}
}
}
void GraphCutSeamFinder::Impl::findInPair(const Mat &img1, const Mat &img2, Point tl1, Point tl2,
Rect roi, Mat &mask1, Mat &mask2)
{
const int gap = 10;
Mat subimg1(roi.height + 2 * gap, roi.width + 2 * gap, CV_32FC3);
Mat subimg2(roi.height + 2 * gap, roi.width + 2 * gap, CV_32FC3);
Mat submask1(roi.height + 2 * gap, roi.width + 2 * gap, CV_8U);
Mat submask2(roi.height + 2 * gap, roi.width + 2 * gap, CV_8U);
// Cut subimages and submasks with some gap
for (int y = -gap; y < roi.height + gap; ++y)
{
for (int x = -gap; x < roi.width + gap; ++x)
{
int y1 = roi.y - tl1.y + y;
int x1 = roi.x - tl1.x + x;
if (y1 >= 0 && x1 >= 0 && y1 < img1.rows && x1 < img1.cols)
{
subimg1.at<Point3f>(y + gap, x + gap) = img1.at<Point3f>(y1, x1);
submask1.at<uchar>(y + gap, x + gap) = mask1.at<uchar>(y1, x1);
}
else
{
subimg1.at<Point3f>(y + gap, x + gap) = Point3f(0, 0, 0);
submask1.at<uchar>(y + gap, x + gap) = 0;
}
int y2 = roi.y - tl2.y + y;
int x2 = roi.x - tl2.x + x;
if (y2 >= 0 && x2 >= 0 && y2 < img2.rows && x2 < img2.cols)
{
subimg2.at<Point3f>(y + gap, x + gap) = img2.at<Point3f>(y2, x2);
submask2.at<uchar>(y + gap, x + gap) = mask2.at<uchar>(y2, x2);
}
else
{
subimg2.at<Point3f>(y + gap, x + gap) = Point3f(0, 0, 0);
submask2.at<uchar>(y + gap, x + gap) = 0;
}
}
}
const int vertex_count = (roi.height + 2 * gap) * (roi.width + 2 * gap);
const int edge_count = (roi.height - 1 + 2 * gap) * (roi.width + 2 * gap) +
(roi.width - 1 + 2 * gap) * (roi.height + 2 * gap);
GCGraph<float> graph(vertex_count, edge_count);
switch (cost_type_)
{
case GraphCutSeamFinder::COST_COLOR:
setGraphWeightsColor(subimg1, subimg2, submask1, submask2, graph);
break;
default:
CV_Error(CV_StsBadArg, "unsupported pixel similarity measure");
}
graph.maxFlow();
for (int y = 0; y < roi.height; ++y)
{
for (int x = 0; x < roi.width; ++x)
{
if (graph.inSourceSegment((y + gap) * (roi.width + 2 * gap) + x + gap))
mask2.at<uchar>(roi.y - tl2.y + y, roi.x - tl2.x + x) = 0;
else
mask1.at<uchar>(roi.y - tl1.y + y, roi.x - tl1.x + x) = 0;
}
}
}
GraphCutSeamFinder::GraphCutSeamFinder(int cost_type, float terminal_cost, float bad_region_penalty)
: impl_(new Impl(cost_type, terminal_cost, bad_region_penalty)) {}
void GraphCutSeamFinder::findInPair(const Mat &img1, const Mat &img2, Point tl1, Point tl2,
Rect roi, Mat &mask1, Mat &mask2)
{
impl_->findInPair(img1, img2, tl1, tl2, roi, mask1, mask2);
}