我转储了视频的某些帧,并希望从中生成一个长方体,如以下示例图像所示:
我想知道是否存在一个MATLAB函数来绘制这样的图?
最佳答案
目前尚不清楚您的视频帧以什么格式开始,因此我假设它们以电影帧的结构数组形式加载到MATLAB中(如here所述)。我将创建一些示例电影数据(单个图像重复200次),以首先向您展示如何将第一帧加载到图像中以及如何在所有帧的顶部和侧面边缘之外创建图像(使用作为长方体的顶面和侧面):
M = repmat(im2frame(imread('peppers.png')),1,200); %# Sample movie data
nFrames = numel(M); %# The number of frames
face1 = frame2im(M(1)); %# Get the image for the front face
[R,C,D] = size(face1); %# Get the dimensions of the image
face2 = zeros(R,nFrames,3,'uint8'); %# Initialize the image for the side face
face3 = zeros(nFrames,C,3,'uint8'); %# Initialize the image for the top face
for k = 1:nFrames %# Loop over the frames
img = frame2im(M(k)); %# Get the image for the current frame
face2(:,k,:) = img(:,end,:); %# Copy the side edge to the side face image
face3(k,:,:) = img(1,:,:); %# Copy the top edge to the top face image
end
上面的代码假定影片帧是RGB images而不是indexed images。如果它们是索引图像,则必须从函数FRAME2IM获取其他colormap参数,然后使用该函数使用IND2RGB将其转换为RGB图像。
接下来,您可以使用SURF函数将立方体的每一边绘制为纹理映射的表面:
offset = nFrames/sqrt(2); %# The offset in pixels between the back
%# corners and front corners of the
%# displayed cuboid
surf([0 C; 0 C],... %# Plot the front face
[R R; 0 0],...
[0 0; 0 0],...
'FaceColor','texturemap',...
'CData',face1);
hold on; %# Add to the existing plot
surf([C C+offset; C C+offset],... %# Plot the side face
[R R+offset; 0 offset],...
[0 0; 0 0],...
'FaceColor','texturemap',...
'CData',face2);
surf([0 C; offset C+offset],... %# Plot the top face
[R R; R+offset R+offset],...
[0 0; 0 0],...
'FaceColor','texturemap',...
'CData',face3);
axis equal %# Make the scale on the x and y axes equal
view(2); %# Change the camera view
axis off %# Turn off display of the axes
set(gcf,'Color','w'... %# Scale the figure up
'Position',[50 50 C+offset+20 R+offset+20]);
set(gca,'Units','pixels',... %# Scale the axes up
'Position',[10 10 C+offset R+offset]);
这是结果图: