キーポイントとドローネ三角形分割を使用して 2 つの画像を変形する単純なアルゴリズムを開発しています。アイデアは単純でなければなりません：
- ソース管理ポイントを選択する
- 目的地のコントロール ポイントを選択します
- ソース フレームと宛先フレームのドローネ三角形分割を取得する
- ソース画像の各ピクセル
- ピクセルが存在するソース三角形に関連するピクセルの重心座標を取得します
- ピクセルが位置する目的の三角形に関連するピクセルの重心座標を取得します
- 関係 Px = w1*v0x + w2*v1x + w3*v2x (y と宛先ピクセルも同じ) を使用して、OUT[PdestX,PdestY] = IN[Px,Py] を割り当てます。
しかし、それは動作しません X_X これは私の matlab ソースです:
function out = myMorph(im1, p_source, p_dest, tri_source, tri_dest)
[h w] = size(im1);
%get single column vectors for source and destination image control points
Psource_x = p_source(:,1);
Psource_y = p_source(:,2);
Pdest_x = p_dest(:,1);
Pdest_y = p_dest(:,2);
%for each intermediate frame...
out = zeros(size(im1));
%get triangles. Each array is 3n x 2, where n is the number of triangles
triangles_source = [];
triangles_dest = [];
for i= 1 : size(tri_source,1)
triangle_s = getTriangle(Psource_x,Psource_y,tri_source,i);
triangle_d = getTriangle(Pdest_x,Pdest_y,tri_dest,i);
triangles_source = cat(1,triangles_source,triangle_s);
triangles_dest = cat(1,triangles_dest,triangle_d);
end
%iterate each pixel
for x=1:h
for y=1:w
%get the source and destination triangle for pixel [x y]
%source triangle
for t = 1 : 3 : size(triangles_source, 1)-2
[w1,w2,w3,inTriangle] = inTri(x,y, ...
triangles_source(t,1),triangles_source(t,2), ...
triangles_source(t+1,1),triangles_source(t+1,2), ...
triangles_source(t+2,1),triangles_source(t+2,2));
if(inTriangle == 1)
break; %point [x,y] must belong to one (and only) triangle
end
end
%source triangle
for k = 1 : 3 : size(triangles_dest, 1)-2
[w1d,w2d,w3d,inTriangleD] = inTri(x,y, ...
triangles_dest(k,1),triangles_dest(k,2), ...
triangles_dest(k+1,1),triangles_dest(k+1,2), ...
triangles_dest(k+2,1),triangles_dest(k+2,2));
if(inTriangleD == 1)
break;
end
end
v_source = [w1*triangles_source(t,1) + ...
w2*triangles_source(t+1,1) + ...
w3*triangles_source(t+2,1), ...
w1*triangles_source(t,2) + ...
w2*triangles_source(t+1,2) + ...
w3*triangles_source(t+2,2)];
v_dest = [w1d*triangles_dest(k,1) + ...
w2d*triangles_dest(k+1,1) + ...
w3d*triangles_dest(k+2,1),...
w1d*triangles_dest(k,2) + ...
w2d*triangles_dest(k+1,2) + ...
w3d*triangles_dest(k+2,2)];
if(inTriangle ~= 1 && inTriangleD ~= 1)
continue;
end
v_source = round(v_source);
v_dest = round(v_dest);
if(v_source(1)>0 && v_source(1) <= h && ...
v_source(2)>0 && v_source(2) <= w && ...
v_dest(1)>0 && v_dest(1) <= h && ...
v_dest(2)>0 && v_dest(2) <= w)
disp('pixel warped')
out(v_dest(1),v_dest(2)) = im1(v_source(1),v_source(2));
end
% else
% out(x,y) = im1(x,y);
end
end
これらは、コントロール ポイントを取得するためのユーティリティ関数です。
%Get control points used to morph im into another image
%im -> source image
%im2 -> destination image
%linesNum -> number of lines
function [P] = getControlPoints(im, controlPtsNum)
close all
P = zeros(controlPtsNum, 2);
%select lines from source image
figure;
imshow(im,[]);title('select control points')
for i=1 : controlPtsNum
%get source control point
[x,y] = ginput(1);
P(i,:) = [x,y];
hold on
plot(x,y,'o','Color','r');
hold off
end
%Get control points used to morph im into another image and do delaunay
%triangulation using the control points
%im -> source image
%im2 -> destination image
%controlPtsNum -> number of control points
function [P,tri] = getControlPointsAndTriangulate(im, controlPtsNum)
P = getControlPoints(im, controlPtsNum);
[h w] = size(im);
%Add corners to control points
P = cat(1, P, [1 1]);
P = cat(1, P, [w 1]);
P = cat(1, P, [1 h]);
P = cat(1, P, [w h]);
tri = delaunay(P(:,1),P(:,2));
hold on
triplot(tri,P(:,1),P(:,2))
hold on
そして、この関数（私はネット上で見つけました）は、ポイントが特定の三角形上にあるかどうかをテストし、u、v、w の値を返します。
function [w1,w2,w3,r] = inTri(vx, vy, v0x, v0y, v1x, v1y, v2x, v2y)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% inTri checks whether input points (vx, vy) are in a triangle whose
% vertices are (v0x, v0y), (v1x, v1y) and (v2x, v2y) and returns the linear
% combination weight, i.e., vx = w1*v0x + w2*v1x + w3*v2x and
% vy = w1*v0y + w2*v1y + w3*v2y. If a point is in the triangle, the
% corresponding r will be 1 and otherwise 0.
%
% This function accepts multiple point inputs, e.g., for two points (1,2),
% (20,30), vx = (1, 20) and vy = (2, 30). In this case, w1, w2, w3 and r will
% be vectors. The function only accepts the vertices of one triangle.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
v0x = repmat(v0x, size(vx,1), size(vx,2));
v0y = repmat(v0y, size(vx,1), size(vx,2));
v1x = repmat(v1x, size(vx,1), size(vx,2));
v1y = repmat(v1y, size(vx,1), size(vx,2));
v2x = repmat(v2x, size(vx,1), size(vx,2));
v2y = repmat(v2y, size(vx,1), size(vx,2));
w1 = ((vx-v2x).*(v1y-v2y) - (vy-v2y).*(v1x-v2x))./...
((v0x-v2x).*(v1y-v2y) - (v0y-v2y).*(v1x-v2x)+eps);
w2 = ((vx-v2x).*(v0y-v2y) - (vy-v2y).*(v0x-v2x))./...
((v1x-v2x).*(v0y-v2y) - (v1y-v2y).*(v0x-v2x)+eps);
w3 = 1 - w1 - w2;
r = (w1>=0) & (w2>=0) & (w3>=0) & (w1<=1) & (w2<=1) & (w3<=1);
なにか提案を？さよなら！
