opencv/modules/stitching/seam_finders.cpp

403 lines
16 KiB
C++

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#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 == GC_COLOR)
return new GraphCutSeamFinder(GraphCutSeamFinder::COST_COLOR);
if (type == GC_COLOR_GRAD)
return new GraphCutSeamFinder(GraphCutSeamFinder::COST_COLOR_GRAD);
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;
images_ = src;
corners_ = corners;
masks_ = masks;
for (size_t i = 0; i < src.size() - 1; ++i)
{
for (size_t j = i + 1; j < src.size(); ++j)
{
Rect roi;
if (overlapRoi(corners[i], corners[j], src[i].size(), src[j].size(), roi))
findInPair(i, j, roi);
}
}
}
void VoronoiSeamFinder::findInPair(size_t first, size_t second, Rect roi)
{
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);
Mat img1 = images_[first], img2 = images_[second];
Mat mask1 = masks_[first], mask2 = masks_[second];
Point tl1 = corners_[first], tl2 = corners_[second];
// 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 PairwiseSeamFinder
{
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 find(const vector<Mat> &src, const vector<Point> &corners, vector<Mat> &masks);
void findInPair(size_t first, size_t second, Rect roi);
private:
void setGraphWeightsColor(const Mat &img1, const Mat &img2,
const Mat &mask1, const Mat &mask2, GCGraph<float> &graph);
void setGraphWeightsColorGrad(const Mat &img1, const Mat &img2, const Mat &dx1, const Mat &dx2,
const Mat &dy1, const Mat &dy2, const Mat &mask1, const Mat &mask2,
GCGraph<float> &graph);
vector<Mat> dx_, dy_;
int cost_type_;
float terminal_cost_;
float bad_region_penalty_;
};
void GraphCutSeamFinder::Impl::find(const vector<Mat> &src, const vector<Point> &corners,
vector<Mat> &masks)
{
// Compute gradients
dx_.resize(src.size());
dy_.resize(src.size());
Mat dx, dy;
for (size_t i = 0; i < src.size(); ++i)
{
CV_Assert(src[i].channels() == 3);
Sobel(src[i], dx, CV_32F, 1, 0);
Sobel(src[i], dy, CV_32F, 0, 1);
dx_[i].create(src[i].size(), CV_32F);
dy_[i].create(src[i].size(), CV_32F);
for (int y = 0; y < src[i].rows; ++y)
{
const Point3f* dx_row = dx.ptr<Point3f>(y);
const Point3f* dy_row = dy.ptr<Point3f>(y);
float* dx_row_ = dx_[i].ptr<float>(y);
float* dy_row_ = dy_[i].ptr<float>(y);
for (int x = 0; x < src[i].cols; ++x)
{
dx_row_[x] = normL2(dx_row[x]);
dy_row_[x] = normL2(dy_row[x]);
}
}
}
PairwiseSeamFinder::find(src, corners, masks);
}
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);
}
}
// Set regular edge weights
const float weight_eps = 1.f;
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::setGraphWeightsColorGrad(
const Mat &img1, const Mat &img2, const Mat &dx1, const Mat &dx2,
const Mat &dy1, const Mat &dy2, 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);
}
}
// Set regular edge weights
const float weight_eps = 1.f;
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 grad = dx1.at<float>(y, x) + dx1.at<float>(y, x + 1) +
dx2.at<float>(y, x) + dx2.at<float>(y, x + 1) + weight_eps;
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))) / grad +
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 grad = dy1.at<float>(y, x) + dy1.at<float>(y + 1, x) +
dy2.at<float>(y, x) + dy2.at<float>(y + 1, x) + weight_eps;
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))) / grad +
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(size_t first, size_t second, Rect roi)
{
Mat img1 = images_[first], img2 = images_[second];
Mat dx1 = dx_[first], dx2 = dx_[second];
Mat dy1 = dy_[first], dy2 = dy_[second];
Mat mask1 = masks_[first], mask2 = masks_[second];
Point tl1 = corners_[first], tl2 = corners_[second];
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);
Mat subdx1(roi.height + 2 * gap, roi.width + 2 * gap, CV_32F);
Mat subdy1(roi.height + 2 * gap, roi.width + 2 * gap, CV_32F);
Mat subdx2(roi.height + 2 * gap, roi.width + 2 * gap, CV_32F);
Mat subdy2(roi.height + 2 * gap, roi.width + 2 * gap, CV_32F);
// 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);
subdx1.at<float>(y + gap, x + gap) = dx1.at<float>(y1, x1);
subdy1.at<float>(y + gap, x + gap) = dy1.at<float>(y1, x1);
}
else
{
subimg1.at<Point3f>(y + gap, x + gap) = Point3f(0, 0, 0);
submask1.at<uchar>(y + gap, x + gap) = 0;
subdx1.at<float>(y + gap, x + gap) = 0.f;
subdy1.at<float>(y + gap, x + gap) = 0.f;
}
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);
subdx2.at<float>(y + gap, x + gap) = dx2.at<float>(y2, x2);
subdy2.at<float>(y + gap, x + gap) = dy2.at<float>(y2, x2);
}
else
{
subimg2.at<Point3f>(y + gap, x + gap) = Point3f(0, 0, 0);
submask2.at<uchar>(y + gap, x + gap) = 0;
subdx2.at<float>(y + gap, x + gap) = 0.f;
subdy2.at<float>(y + gap, x + gap) = 0.f;
}
}
}
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;
case GraphCutSeamFinder::COST_COLOR_GRAD:
setGraphWeightsColorGrad(subimg1, subimg2, subdx1, subdx2, subdy1, subdy2,
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))
{
if (mask1.at<uchar>(roi.y - tl1.y + y, roi.x - tl1.x + x))
mask2.at<uchar>(roi.y - tl2.y + y, roi.x - tl2.x + x) = 0;
}
else
{
if (mask2.at<uchar>(roi.y - tl2.y + y, roi.x - tl2.x + x))
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::find(const vector<Mat> &src, const vector<Point> &corners,
vector<Mat> &masks)
{
impl_->find(src, corners, masks);
}