如何在MATLAB中重现这个长方体图?

时间:2010-09-02 13:43:29

标签: matlab 3d plot

我倾倒了一些视频帧,想要从中生成一个长方体,如下面的示例图片所示:

alt text

我想知道是否存在MATLAB函数来做这样的情节?

1 个答案:

答案 0 :(得分:2)

目前尚不清楚视频帧的格式是什么,所以我假设它们作为电影帧的结构数组加载到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),首先向您展示如何将第一帧加载到图像中,以及如何从所有帧的顶部和侧边创建图像(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

上面的代码假设电影帧是RGB images而不是indexed images。如果它们是索引图像,则必须从函数FRAME2IM获取附加的colormap参数,然后使用该参数使用函数IND2RGB将图像转换为RGB图像。

接下来,您可以使用SURF函数将立方体的每一面绘制为纹理映射表面:

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]);

这是最终的数字:

alt text